Ovid: Chapman’s Orthopaedic Surgery

Editors: Chapman, Michael W.
Title: Chapman’s Orthopaedic Surgery, 3rd Edition
> Table of Contents > SECTION
VIII – THE SPINE > Principles and Anatomy > CHAPTER 138 –

Robert G. Watkins
R. G. Watkins: Los Angeles, California, 90033.
As late as 1980, spinal surgeons, and therefore spinal
patients, were severely limited in the options available to them for
surgical treatment. The source of this limitation was a combination of
technology and the experience in surgical approaches. Very few spinal
surgeons had the ability to approach every aspect of the spine with the
optimal exposure. Spinal access surgeons were few and far between. The
microscopic and endoscopic approaches that protect normal tissue and
speed recovery were scarcely available to unavailable. The evolution of
spinal surgery now allows the surgeon to approach their pathology so as
to optimize the resection of a pathologic lesion and reconstruct the
spine to optimal biomechanical advantage. Perfecting the approach is
the first step to perfecting the surgery and a major step in protecting
the patient.
  • For the posterior cervical exposure of
    any level, position the patient’s head in the self-retaining
    neurosurgical head fixation device that is attached to the surgical
    table. Attach the drapes to the patient’s neck with stay sutures. Neck
    flexion will increase exposure, but flexion is limited by the type of
    pathologic process present, usually to a neutral, slightly flexed
    position. In the presence of spinal instability, confirm the position
    of the spine with radiographs.
  • Incise the skin and subcutaneous tissue
    in the midline to the fascia, and obtain hemostasis with rapid
    application of hemostats and electrocautery. Insert self-retaining
  • Deepen the incision with the cautery
    knife, staying within the thin white median raphe; avoid cutting muscle
    tissue. The medial raphe of the cervical spine is a


    structure that does not follow a straight path. Open the median raphe
    to the spinous processes of C-2 and C-3, the occiput, or any level
    needed. In children, expose no spinal levels unnecessarily to avoid
    spontaneous fusion at adjacent levels, including the occiput.

  • With a #15 blade or cutting cautery,
    expose the bulbous bifid tips of the spinous processes. The ligamentous
    attachments to C-2 are very prominent. The large spinous process of C-7
    and T-1 can be identified. Identify any spina bifida of the cervical
    spine on preoperative radiographs and be aware of these areas at
    surgery. Insert the Cobb elevator, first facing up to elevate the tip
    of the spinous process subperiosteally, then facing down to complete
    the subperiosteal elevation from medial to lateral for a width of
    approximately 1 inch (2.5 cm) at each level. At levels below C-2,
    identify the medial edge of the facet joint at the base of the lamina
    and pack each level as it is exposed. When necessary, expose the
    occiput with elevators. Insert the self-retaining retractors to expose
    the base of the skull and the dorsal spine of C-2. The area in between
    will contain the ring of C-1. This is often very deep compared with the
    spinous process of C-2.
  • Maintaining firm lateral retraction of
    the wound, identify the posterior tubercle of C-1 longitudinally in the
    midline by probing with a sharp Cobb elevator. Begin the subperiosteal
    dissection to expose the bone.
  • Often the C-1 ring is very thin, and
    direct pressure can fracture it or cause the instrument to slip off the
    ring and penetrate the atlantooccipital membrane. Elevation on this
    ring can be very dangerous if there is subluxation with constriction of
    the posterior dura under this ring. The dura may be vulnerable on both
    the superior and inferior edges of the ring of C-1.
  • At the level of C-1, dissect laterally
    only approximately 1.5 cm. The second cervical ganglion is an important
    landmark on the ring of C-1 laterally; it lies approximately 1.5 cm
    laterally on the lamina of C-1 in the area of the groove for the
    vertebral artery. Carefully identify the most medial aspect of the
    groove for the vertebral artery and vein on the superior border of the
    C-1 ring. The bluish color of the vein is visualized first. By seeing
    the initial ridge or the vein, damage to the artery can be avoided.
    There is seldom any indication for dissection lateral to the groove of
    the vertebral artery on C-1. The vertebral artery and vein are
    vulnerable in the groove; in addition, as the artery passes from the
    foramen transversarium of C-2 to that of C-1, it is in close proximity
    laterally and posteriorly to the joint (29) (Fig. 138.1 and Fig. 138.2).
    Figure 138.1.
    The course of the vertebral artery is from the foramen transversarium
    of C-1 posteriorly in the region of the C1–C2 articulation through the
    transversarium of C-1, then posteromedially to the posterior rim of C-1.
    Figure 138.2.
    The anterior view without vertebral bodies emphasizes the formation of
    the anterior spinal artery. There are numerous variations in this
    formation, ranging from a unilateral vertebral artery contribution to
    no contribution.
  • The vertebral artery enters the foramen
    transversarium at the sixth vertebra and progresses cephalad. It exits
    through the foramen transversarium of C-1 and progresses posteriorly as
    well as medially in the groove of the superior border of C-1 toward the
    midline, then turns cephalad along the spinal cord to enter the foramen
    magnum. The vertebral artery can be damaged by penetrating the
    atlanto-occipital membrane off the superior border of the ring of C-1
    more lateral than the usually safe 1.5 cm from the midline.
  • Following exposure of the ring of C-1 and
    exposure to bone of the posterior occiput, different operative
    procedures require exposure of the dura under the edge of the foramen
    magnum (17,25,26).
    Never attempt to decompress the posterior fossa under the edge of the
    foramen magnum without sufficient visualization of the area cephalad to
    the foramen. This is best accomplished by placing two burr holes just
    off the midline of each side of the skull (Fig. 138.3).
    The caudal extent of the holes is usually determined by the angle of
    the drill on the skull as limited by the patient’s shoulders.
    Figure 138.3. Posterior approach to the foramen magnum.
  • In the posterior approach to the foramen
    magnum, first place burr holes in the occiput above the foramen magnum.
    Two parasagittal holes allow removal of bone from the dura with a
    Harrison-type rongeur. Careful dissection medially from the burr holes
    provides protection from the often significant fragile venous sinus,
    and dissection caudally approaches the foramen magnum. After removal of
    the occiput including the bony rim of the foramen magnum, which is a
    sharp-lipped structure projecting directly anterior in the transverse
    plane, the fibrous attachment of the inner periosteum of the skull to
    the dura at the rim of the foramen magnum is encountered. When a
    transverse venous sinus in this area



    torn, bleeding can be significant. Attachment to the dura in this area
    produces a dural leak unless the area is carefully dissected.

  • Penetrate to the inner periosteum and the
    bone edge with a small dissector. Expand the hole caudally to the
    foramen with rongeurs. The edge itself curves under and projects
    anteriorly. The periosteum of the skull at this point is often
    conjoined with the dura of the spinal cord. There is a median venous
    sinus in the midline, and the fascial attachment of the periosteum of
    the skull to the dura often contains a transverse sinus as well.
  • Passing instruments under the edge of the
    foramen can produce dangerous bleeding in the posterior fossa with no
    means of control. Therefore, resect the bone down to this edge from
  • For a more lateral approach to the C1–C2
    facet joint, the vertebral artery between C-1 and C-2 must be
    identified. In rotatory dislocations of C1–C2, the artery is stretched
    tightly across the joint on the side that C-1 is anterior to C-2, and
    it is easily damaged (29).
  • For nerve root exposure below C-2,
    identify the junction of the lamina and the inferior facet. Then
    identify the junction of the interlaminar area and the facet joint.
    Expanding these areas with a burr or a micro-Kerrison rongeur allows
    entry into the intervertebral foramen and exposure of the nerve root.
For preoperative preparation, take oral and nasal cultures of the patient in case problems develop later (1).
Use standard prophylactic antibiotics because no special antibiotic
coverage for normal oral flora is needed. I do not use preoperative
antiseptic gargles or tetracycline (7).
Always perform a tracheostomy, using a short-cuffed tube.
  • Position the patient supine with the head
    slightly flexed on occipital pads, or put the head into a halo. A more
    upright position can be used with certain precautions.
  • The Boyle-Davis or McIver ear, nose, and
    throat (ENT) retractor allows depression of the tongue and
    self-retaining retraction of the mouth. The lips and teeth should be
    adequately padded.
  • Incise the soft palate with a curvilinear
    incision around the uvula, and retract the cut edges with stay sutures
    to the lateral walls of the oropharynx or to an especially bent,
    blunt-tipped Gelpi retractor (7,14). Prep the oropharynx with povidone-iodine (Betadine) solution and reculture it.
  • Enhanced hemostasis by injecting the posterior pharyngeal tissue with a solution of 5% lidocaine and 1:500,000 epinephrine.
  • After palpation and radiographic
    confirmation of the ring of C-1, make a vertical incision from
    approximately 1 cm cephalad to the tip of the odontoid to 2 cm distal
    to the anterior tubercle of C-1. Incise the four layers (posterior
    pharyngeal mucosa, superior constrictor muscle of the pharynx, the
    prevertebral fascia, and the anterior longitudinal ligaments) directly
    to the bone.
  • Bluntly dissect the soft tissue off the body of C-2 below the odontoid and off the anterior tubercle of C-1.
  • Caution: The longus
    colli muscle inserts on the anterior tubercle of C-1, and sharp
    dissection may be needed to remove it. Venous bleeding may arise from
    the recesses just lateral to the base of the odontoid.
  • When necessary, the lateral masses of C1–C2 can be exposed by bluntly dissecting the bone both transversely and vertically.
  • Caution: Avoid
    plunging lateral to the facet joints. To avoid damage to the internal
    carotid, do not pass a stay suture too deeply into the lateral
    pharyngeal wall.
  • Remember, this is a deep wound, requiring
    long instruments with fine tips. Most operations done with this
    exposure require use of the microscope for lighting and magnification.
  • After the bony work is completed and good
    hemostasis is obtained, close the posterior pharynx in a single layer
    with interrupted absorbable sutures.
  • Position the patient supine with the
    appropriate support for the cervical spine mentioned earlier. For two
    levels of pathology, it is a transverse incision, one fingerbreadth
    medial to the medial border of the sternocleidomastoid. Open layers in
    a fashion similar to that used with the standard cervical approaches.
  • For higher anterior approaches to C-1,
    C-2, and C-3, identify the superior thyroid artery and vein. The
    superior thyroid artery arises from the external carotid artery at
    approximately the level of the hyoid bone. It crosses through the
    carotid triangle, arches deep to the strap muscles, and enters the
    lateral superior aspect of the thyroid gland. Retract the superior
    thyroid artery and vein inferiorly.
  • Identify and retract the hypoglossal
    nerve. The hypoglossal nerve is found passing from lateral to medial
    superficial to the external carotid, lingual, and facial arteries (Fig. 138.4).
    It exits the skull in close proximity to the vagus nerve and courses
    beneath the internal carotid artery and internal jugular vein, becoming
    superficial at the angle of the mandible. After the usual point of
    identification of the hypoglossal nerve over the arteries, it passes
    deep to the tendon of the digastric muscle and stylohyoid muscle for
    distribution to the muscles


    of the tongue. Retract the hypoglossal nerve cephalad; usually, the superior thyroid artery and vein are retracted caudad.

    Figure 138.4.
    Dissected anatomy of the carotid triangle and area just below
    emphasizes the importance of identification of the hypoglossal nerve
    before ligation of the arterial structures in this area. The most
    common approach is cephalad to the superior thyroid artery and caudad
    to the digastric muscle. SCM, sternocleidomastoid.
  • Be certain of the identification of the
    hypoglossal nerve before ligating any structure. It is a superficial
    structure, first coursing vertically and parallel to the carotid
    sheath, then horizontally, crossing medially over the carotid and its
  • Identify the lingual artery, which arises
    from the external carotid. From the level of the hyoid, it crosses
    under the digastric and stylohyoid muscles in its ascent to the oral
  • Identify and ligate the facial artery.
    The facial artery next leaves the external carotid artery, coursing
    under the ramus to the mandible within the carotid triangle. It passes
    deep into the digastric muscle and enters the face at the anterior edge
    of the mastoid after crossing on the submandibular gland.
  • Identify the digastric muscle. This
    muscle is easily retracted cephalad with the hypoglossal nerve. When
    necessary, divide the stylofascial band running from the stylohyoid
    process to the posterior pharynx.
  • Difficulties may be encountered with the
    superior laryngeal nerve, both external and internal branches, and the
    pharyngeal branches of the vagus nerve. These nerves should be
    identified and retracted, but they frequently suffer from the
    retraction. Continue to use finger palpation to identify the spine and
    the carotid artery.
  • Retract the carotid sheath and the
    ligated stumps of the lingual and facial arteries laterally, and
    retract the musculovisceral column medially with deep right-angle,
    hand-held blunt retractors.
  • With a Kittner dissector, make a careful, blunt dissection at this point, to identify the prevertebral fascia.
  • Elevate the fibers of the longus colli
    muscle and fascia off the vertebral body in a lateral and cephalad
    direction. Insert the sharp claw blades of the Cloward retractor under
    the longus colli. The smooth-tipped blades can be used if firm fixation
    cannot be obtained under the longus colli (3). Deep hand-held retractors are also quite effective (Fig. 138.5).
    Figure 138.5. The spine is exposed with deep retractor blades.
The external investing fascia forms the anterior and posterior sheaths of the sternocleidomastoid muscle and


the fascial covering of the visceral structures of the neck (10).
This investing layer of cervical fascia is attached inferiorly to the
acromion, clavicle, and manubrium of the sternum in an outer and inner
layer superiorly to the hyoid bone, posteriorly to the mandible and
mastoid processes, and superior to the nuchal line. The interval
between the two laminae of the external investing fascia is called the
suprasternal space, or the space of Burns. This space, which contains
the anterior jugular veins and sternal head of the sternocleidomastoid,
is referred to as the cul-de-sac of Bruger. Communication between the
anterior and external jugular veins is channeled through this inner
laminar area.

The middle cervical fascia attaches to the carotid
sheath and joins the external investing fascia at the posterior border
of the sternocleidomastoid muscle. Inferiorly, the middle cervical
fascia attaches to the posterior surface of the sternum, as do the
muscles that they cover. It is the middle cervical fascia that attaches
to the clavicle and forms the loop for the inferior belly of the
omohyoid muscle.
The prevertebral fascia is continuous with the
endothoracic fascia caudally, and laterally it covers the levator
scapulae and splenius muscles. It extends posteriorly to attach to the
spinous processes of the vertebrae. In the neck and throughout the
spinal column, it covers the longus colli and capitus muscles and is
secured to the tips of the transverse processes.
The origin of the anterior scalene muscle rises from the
anterior tubercles of the transverse processes of C-3, C-4, C-5, and
C-6. It inserts into the scalene tubercle on the inner border of the
first rib and into the ridge on the cranial surface of the rib ventral
to the subclavian groove. The scalenus medius originates from the
posterior tubercle of the transverse processes of the last six cervical
vertebrae and inserts into the first rib.
The scalenus medius is a muscular reinforcement of
Sibson’s fascia. These fascial connections and the scalenus minimus
connect the transverse processes of the seventh cervical vertebra to
the first rib. Sibson’s fascia, as a portion of the prevertebral
fascia, becomes continuous with the endothoracic fascia on the inner
surface of the first rib. Extending medially between the anterior
scalene muscle and the spine is the all-important retropharyngeal
fascial cleft. This is the space beneath the visceral structures,
superficial to the prevertebral fascia; it is in this space that
retraction and work on the anterior portion of the spine takes place.
  • Position Gardner-Wells tongs or
    headhalter traction for cervical traction. Position the head in slight
    extension and rotation to the right. Contour a small, curved sand bag
    under the neck to support the spine. Drape off the entire neck with
    adhesive towel drapes. Select the level of the skin incision.
    Superficial landmarks are used to determine the appropriate placement
    of the skin incision over the appropriate level of the spine. For
    approaches to C-1, C-2, and C-3, start the incision midline extended to
    the lateral border of the carotid sheath, one fingerbreadth below the
    angle of the madible. For approaches to C2–C3 start the incision at the
    midline and extend it to the lateral border of the sternocleidomastoid
    at the level of the cephalad margin of the thyroid cartilage. For
    C4–C5, start the incision at the midline and extend it to the medial
    border of the sternocleidomastoid at the level half way between the
    cricoid cartilage and the superior border of the tyroid cartilage. For
    C5–C6, start the incision at the midline on the cephalad margin of the
    cricoid cartilage and extend it to the medial border of the
    sternocleidomastoid. For C6–C7, start the incision at the midline of
    the caudal margin of the cricoid cartilage and extend it to the medial
    border of the sternocleidomastoid. For C7–T1, start the incision at the
    midline; extend it just lateral of the medial border of the
    sternocleidomastoid, halfway between the cricoid cartilage and the
    clavicle. We prefer the midline starting point, because retraction of
    the medial muscular visceral column is the strongest structure
    requiring retraction. Having the skin open to the midline eases that
    retraction. The self-retaining retractor is


    placed in the midline. Having the skin open to the midline aids in that retraction.

  • After making a transverse skin incision at the appropriate level (Fig. 138.6),
    dissect through the subcutaneous tissue to the platysma muscle. Elevate
    the platysma muscle with Adson forceps, and open it carefully, in the
    line of the fibers, when possible. Beware of damage to veins and the
    sternocleidomastoid muscle (2,21). Insert a spring retractor.
    Figure 138.6.
    The more cosmetically suitable transverse incision is made at the
    appropriate level and should allow exposure of up to two discs and
    three vertebrae. A vertical incision can be used for an even greater
  • Open the superficial cervical fascia and identify the medial border of the sternocleidomastoid muscle (25).
    The first key to successful exposure is adequate identification of the
    medial border of the sternocleidomastoid so that it may be retracted
    laterally (23) (Fig. 138.7).
    With identification of this medial border, bluntly develop the interval
    between the sternocleidomastoid muscle and the sternohyoid muscles.
    Retract the posterior cutaneous nerves. Bluntly dissect the soft tissue
    and spread it vertically in this interval.
    Figure 138.7.
    The key to the dissection at this point is to identify the medial
    border of the sternocleidomastoid muscle. With lateral retraction of
    the sternocleidomastoid, the interval between this muscle and the
    medial strap msucles is delineated.
  • Retract the sternocleidomastoid laterally
    and the strap musculature medially with angled retractors. Identify the
    middle cervical fascia. The omohyoid muscle crosses from proximal
    medial to lateral distal through the middle cervical fascia at C6–C7.
    Retract the omohyoid; when necessary, divide it and later repair it in
    its midportion.
  • After retracting the sternocleidomastoid
    muscle laterally and the strap musculature medially, identify the
    arteriovenous structures of the middle cervical fascial layer (Fig. 138.8).
    Palpate the carotid pulse. Open the midline cervical fascia medial to
    the carotid artery. Ligate and tie the medial thyroid vein. Retract
    cephalad the superior thyroid artery and retract caudad the inferior
    thyroid artery to expose the midcervical spine.
    Figure 138.8. Arteriovenous structures of the middle cervical fascial layer.
  • Spread the middle cervical fascia just medial to the carotid sheath (23), with finger dissection spreading vertically and horizontally (3).
    Identify the inconstant middle thyroid vein crossing at approximately
    C-5, and ligate and divide it when needed. Identify the spine with
    finger palpation of the anterior surface of the vertebral body. Insert
    a blunt, nonlipped Cloward hand-held retractor into the wound directly
    down to the spine. Hold the retractor on the right longus colli. Beware
    of entering the tracheoesophageal groove (and thereby damaging the
    recurrent laryngeal nerve with the retractor tip) (19).
  • Distally retract the inferior thyroid
    artery and vein at the C6–C7 level, and proximally retract the superior
    thyroid artery and vein with the superior laryngeal nerve at C3–C4.
  • Do not mistake the transverse process for
    the anterior surface of the vertebral body because an incision deep in
    this area will damage the longus colli, the sympathetic chain, and
    possibly the vertebral artery. An incision into the longus colli
    produces bleeding.
  • Palpate a disc in the midline of the
    spine and open the prevertebral fascia with a small dissector
    longitudinally until the disc can be identified. If the finger dissects
    directly to the spine and the retractor is then inserted, the esophagus
    cannot be seen. The empty esophagus is only a soft, flat ribbon-like
    structure simulating the musculature over the anterior portion of the
    spine. Always use either an esophageal stethoscope or a nasotracheal
    tube to identify the esophagus.
  • Insert a needle into a disc for lateral radiographic confirmation of the level.
  • Retract the esophagus, trachea, and
    anterior strap muscles medially and the carotid sheath and
    sternocleidomastoid muscle laterally.
  • Incise the prevertebral tissue in the
    midline on the disc. Use a bipolar coagulator along the medial edge of
    the longus colli as needed. Using sharp periosteal elevators, fashion a
    flap of muscle under which the retractor can be inserted laterally from
    the midline. Insert the clawed blades of the Cloward deep
    self-retaining retractor under the longus colli on both sides of the
    spine. To expose the desired disc, use the blunt-tipped Cloward
    retractor vertically (3).
  • Insert the clawed retractor first. Hold
    it down on the spine while inserting the near retractor. The Cloward
    curved periosteal elevator can lift up the flap for insertion of the
    blade retractor.
  • After hemostasis has been achieved, close
    the deep wound by removing the retractors. Use subcuticular skin
    closure, and always use a closed suction wound drainage system.



  • Place the patient in the supine position
    with the neck slightly hyperextended and rotated away from the side of
    the approach. Use an inflatable cervical pillow for support; a small
    roll under the shoulder often helps to extend the neck.
  • Caution: Location of
    the thoracic duct and recurrent laryngeal nerve becomes even more
    important at this level. Approaches from the left for C6–T2 are
    directly in the vicinity of the thoracic duct. Identify the thoracic
    duct when possible and protect it. A large fatty meal the day before
    surgery will help. If the thoracic duct is inadvertently divided,
    double ligate both ends well. The approach to the right definitely
    requires identification and protection of the recurrent laryngeal
    nerve. I recommend the left supraclavicular approach to avoid risk to
    the recurrent laryngeal nerve.
  • Make a transverse incision approximately
    one fingerbreadth above the clavicle from the midline to the posterior
    border of the sternocleidomastoid muscle. After the skin and
    subcutaneous tissue are divided and small skin self-retaining
    retractors are placed, incise the playtsma muscle in the line of the
    incision. As in the higher approaches, identification of the medial
    border of the sternocleidomastoid muscle is imperative.
  • In addition, identify and define the
    anterior and posterior borders of the sternocleidomastoid muscle. The
    external jugular vein, although somewhat variable, is usually directly
    in the operative field, and the anterior jugular vein is positioned
    more medially. Divide it, if necessary.
  • Incise the external investing fascia.
    Pass a probe or finger laterally from the medial border of the
    sternocleidomastoid to clear off the venous structures underneath the
    clavicular head of the sternocleidomastoid.
  • Divide the sternocleidomastoid laterally to medially 1 inch from its insertion, watching for the internal jugular vein (12).
    If required for visualization, remove the sternal head of the
    sternocleidomastoid muscle in the same fashion. Eventual reattachment
    depends on suturing the fascial covering of the muscle.
  • Retract the divided sternocleidomastoid
    in a cephalad-caudad direction with self-retaining blunt retractors.
    The floor of the incision, at this point, consists of the middle
    cervical fascia, which contains the omohyoid and the sternohyoid
  • Enter the middle cervical fascia lateral
    to the carotid sheath. Bluntly dissect to the surface of the anterior
    scalene muscle. The superficial surfaces of the anterior scalene are
    composed of the outer layer of prevertebral fascia, which is the third
    and deepest of the fascial layers dealt with in this approach. Lying on
    the surface of the anterior scalene muscle is the phrenic nerve. The
    phrenic nerve crosses from lateral to medial, and cephalad to caudad.
    Retract the phrenic nerve medially after freeing it from the surface of
    the anterior scalene muscle. Identify the large internal jugular vein
    medially and feel for the carotid pulse. Although retraction of the
    carotid sheath is possible laterally, attempt to retract the internal
    jugular vein and carotid sheath medially (24).
    Retract the phrenic nerve to obtain good visualization of the anterior
    scalene, which is between the phrenic nerve and the middle scalene. The
    brachial plexus and suprascapular nerves are more superficial at the
    lateral border of the anterior scalene.
  • Delineate the medial and lateral borders
    of the anterior scalene muscle. The fascia on the deep surface of the
    anterior scalene is Sibson’s fascia, a continuation of the prevertebral
    fascia that encloses this muscle. The apex of the parietal pleura and
    lung form the undersurface of Sibson’s fascia.
  • Retract the anterior scalene laterally.
    Now carry out blunt dissection medially under the retracted carotid
    sheath. Stay on the prevertebral fascia of the spine.
  • If more exposure is needed, carefully
    approach under the anterior scalene without violating the major
    portions of Sibson’s fascia, and divide the anterior scalene muscle.
    The scalene can be retracted cephalad to caudad with self-retaining
    blunt retractors. Sibson’s fascia now makes up the floor of the wound;
    the large internal jugular vein and the carotid sheath are located
    medially; the apex of the lung is beneath Sibson’s fascia in the floor
    of the wound; and laterally, the brachial plexus courses superficial to
    the scalenus medius. The proximal portion of the anterior scalenus
    muscle may be dissected from the anterior tubercle of the transverse
    processes to allow greater exposure of the spine or brachial plexus (22).
  • Incise Sibson’s fascia at the transverse
    processes and bluntly retract it inferiorly. This retracts the pleura
    of the lung, which is usually at the T-1 level. Mobilize the recurrent
    laryngeal nerve medially with the carotid sheath and medial visceral
    column. Expose the spine by opening the fascia in the midline over the
    body. The transverse processes and rib heads can be exposed (18).
  • Dissect to the second and third rib
    heads. This produces a rather lateral exposure of the spine. From the
    rib heads, dissect medially to enter the retropharyngeal fascial cleft
    on the anterior surface of the spine without having to dissect the
    longus colli muscle. Identify the vertebral artery entering the spine
    at C-6. The subclavian vein courses on the floor of the wound.
  • If the approach is done from the left,
    the junction of the internal jugular veins and the subclavian veins
    will contain the thoracic duct. Identify the thoracic duct. In case of
    damage, double ligate it proximally and distally. Chylothorax can be
    prevented with proper ligation.


    a more judicious approach involves blunt dissection, progressing
    cephalad to caudad, as has been described for the transverse processes
    of C-5, C-6, and C-7, to the rib head of the first rib down on the
    spine. This will sweep most of these structures cephalad to caudad. The
    danger, of course, lies in cutting restraining structures that cross
    the field. The sympathetic chain (stellate ganglion at C-7) lies on the
    rib heads in a lateral position. Avoid damage by dissecting more

Third rib resection is used for the transthoracic
approach to the T1–T4 area. Resection of the third rib allows greater
spreading of the intercostal area than does second rib resection (13).
The cephalad extension of the exposure is enhanced with kyphosis
deformity of the cervicothoracic junction area. The second rib can be
removed if the operative exposure is inadequate.
  • Place the patient in the lateral
    decubitus position, with the left side up. Prep and drape the entire
    left upper extremity in a sterile manner (Fig. 138.9).
    Figure 138.9. Skin incision for third rib resection for the transthoracic approach.
  • Incise the skin and subcutaneous tissue
    from the lateral paraspinous area at T-2, along the medial caudal
    border of the scapula, under the axilla to the costal cartilage of the
    third rib.
  • Carefully divide each subsequent muscle
    layer down to the level of the rib, sectioning portions of the
    trapezius, latissimus dorsi, rhomboid major, and serratus posterior as
    needed. Careful dissection with electrocautery and meticulous
    cauterization of each muscle bleeding point allows exposure to the
    outer periosteum of the third rib with a minimal amount of bleeding. As
    the muscle layers are divided, retract the scapula cephalad and
    medially to tense the muscle tissue for easier cutting. Palpate the
    chest wall cephalad for identification of the third rib. Remember that
    the first rib is situated inside the second; this is important for
    reaching the correct rib level (Fig. 138.10).
    Figure 138.10. Elevation of the scapula aids in the division of the muscles attached to the scapula and allows visualization of the third rib.
  • Dissect the external periosteum off the third rib with periosteal elevators. Excise the third rib from the angle


    of the rib to the costal cartilage. Open the rib bed as in the standard thoracotomy approach (Fig. 138.11).
    The rib bed consists of periosteum, endothoracic fascia, and parietal
    pleura. Incise the parietal pleura, carefully avoiding damage to the
    underlying lung. Pick up the inner periosteum of the rib bed with Adson
    forceps and open the rib bed with scissor tips or fine dissection with
    a knife blade. To avoid lung and pleural adhesions just under the rib,
    complete the opening of the rib bed with semiclosed scissors, using a
    finger to clear lung from the undersurface.

    Figure 138.11. Excise the third rib from the angle of the rib to the costal cartilage.
  • Use the Feochetti rib spreader to open the intercostal area. Deflate or retract the lung with a spatula-type retractor (Fig. 138.12).
    Figure 138.12. With the rib bed open, place the Feochetti rib-separating retractor and retract the lung with a spatula lung retractor.
  • Identify the aorta, spine, ribs, parietal
    pleura, and veins under the parietal pleura in the wound. The highest
    intercostal vein is usually seen.
  • Use an Adson forceps and Metzenbaum scissors to open the parietal pleura delicately over the costovertebral articulations.
  • Identify the prominent soft or white
    tissue of the intervertebral disc. This is a relatively avascular,
    safer plane for dissection than the surface of the vertebral body. Make
    an intraoperative radiograph to verify the level.
  • P.3644

  • Dissect each intercostal vessel, tying
    and ligating it over the vertebral body. Bluntly dissect the soft
    tissue from the vertebral body (Fig. 138.13).
    Figure 138.13.
    After the parietal pleura is opened, bluntly dissect its edges off the
    spine with a “peanut” or sponge. The parietal pleura may be sutured
    back laterally with stay sutures when necessary for continued
  • Fully expand the lung and visualize in
    all areas before closure. Close the parietal pleura over the spine
    whenever possible. Place the chest tube through a separate aperture,
    preferably in the ninth intercostal space. Protect the lung during
    closure. Close the chest with the rib approximator. Close the rib bed
    with interrupted permanent braided Dacron sutures. The chest tube can
    usually be removed within 48 to 72 hours, depending on drainage and
    expansion of the lung.
The standard thoracotomy approach is used for safe
exposure of vertebral levels T-2 to L-2. Rib selection depends on the
location and extent of the pathologic process. Anatomic variations at
the cervicothoracic and thoracolumbar junction dictate the rib to be
taken. Choose the rib to be resected for a certain vertebral level by
one of two methods:
  • When the pathology dictates a direct
    anterior approach to the vertebral column (e.g., kyphotic tuberculous
    abscess), choose the rib directly horizontal to the vertebral level at
    the midaxillary line in an anteroposterior chest radiograph. The rib
    removed must be cephalad to the lesion to give adequate proximal
    exposure of the lesion (13).
  • When direct access to the spinal canal is
    needed at one disc (e.g., ninth rib to the T8–T9 disc), use a left
    approach because it is much easier to deal with the aorta and the
    segmental vessels from the left side. For patients with a large abscess
    in the right chest or in other circumstances that dictate a right
    thoracic approach, be prepared to mobilize the vena cava and associated
    veins from that side.
    • Place the patient on the bean bag. Use a
      double-branched endotracheal tube into the right and left mainstem
      bronchi to allow selective collapse of the left lung. Center the
      midthorax of the patient over the break in the table. Pad the dependent
      axilla, and pad and protect the left arm. Stabilize the pelvis with a
      strap to the table. Place a pillow between the legs, and pad all the
      bony prominences. Flex the table to allow better exposure.
    • Open the skin and subcutaneous tissue
      from the lateral border of the paraspinous musculature to the
      sternocostal junction over the rib to be resected. Inject the incision
      with 1:500,000 epinephrine. Place the thoracotomy incision slightly
      tangential to the rib to be resected, allowing easier resection of more
      than one rib if necessary.
    • After inserting the self-retaining
      retractors, extend the wound with the electrocautery down through the
      muscle layers to the thorax. When necessary for full exposure, the
      latissimus dorsi, trapezius, and rhomboid major and minor muscles can
      be sectioned.
    • After the chest wall is exposed, count
      the ribs from the twelfth up to the appropriate rib or from the first
      rib downward. The first rib appears to be inside the second when one is
      palpating from this angle, and it is often difficult to find. Each rib
      articulates with the superior portion of the body in the area of the
      disc space of the level above. Therefore, the twelfth rib inserts
      closer to the T11–T12 intervertebral disc space. Confirm identification
      of the rib with a radiograph.
    • P.3645

    • Expose the outer periosteum of the rib
      with the electrocautery and cut directly to the bone through the
      periosteum from the angle of the rib to the costal cartilage. Elevate
      the periosteum off the outer rib surface. Use the curved-tip rib
      elevator to strip the superior and inferior borders of the rib,
      maintaining an intact elevated periosteum. Elevate the inner periosteum
      of the undersurface of the rib with the Doyen elevator.
    • Caution: Avoid
      damaging the intercostal vessels that course on the inferior surface of
      the rib. Elevate the periosteum of the rib by cutting with the elevator
      directly on bone. Avoid plunges that might inadvertently enter the
    • With the intact periosteum freed from the
      rib, cut the rib with the rib cutter as far posteriorly as necessary
      between the costotransverse joint and the angle of the rib and
      anteriorly at the costal junction. Remove the rib and save it for bone
      graft. Lightly wax the bone on the end of the rib after rasping to make
      sure there are no ragged edges. Tie a sponge on the tip of the stump to
      protect the surgeon during the procedure.
    • Pick up the inner periosteum of the rib
      bed with Adson forceps and open the rib bed with scissor tips. Avoid
      lung and pleural adhesions. Complete the opening of the rib bed with a
      semiclosed scissors after using a finger to clear lung from the
      undersurface. When pleural adhesions exist, first attempt to dissect
      the adhesions bluntly with the finger or sponge stick. If necessary,
      sharply dissect dense adhesions and ligate vascular structures.
    • Retract the lung medially with a spatula
      lung retractor or deflate it. Retraction of the lung should be removed
      at least every 20 minutes to allow adequate expansion of the lung and
      to prevent postoperative atelectasis. Insert the Feochetti separator in
      the rib resection defect, with moist lap sponges over the edges. Expand
      the Feochetti separator to allow adequate visualization inside the
      thoracic cavity. Flexion of the table may be of benefit.
    • The anatomy of the spine at this point is
      obscured by the reflection of the parietal pleura as it covers the
      soft-tissue structures over the spinal column. Elevate the parietal
      pleura with Adson forceps and open it with Metzenbaum scissors. Extend
      the opening of the parietal pleura cephalad and caudad on the spine by
      cutting over a peon dissected under the pleura. The presence of a large
      paravertebral abscess at this point means only that the abscess should
      be exposed just as the spine would be. When an abscess is present, cut
      its outer wall longitudinally and approach the spine through the
    • The disc is the more prominent, softer,
      white structure of the spine. The discs are relatively avascular and a
      much safer area for dissection. An intercostal vein and artery cross
      the midportion of each vertebral body.
    • Bluntly dissect the edges of the parietal
      pleura off the spine with a Kittner dissector or sponge. Elevate the
      pleura on the discs and lift it off the vessels on the vertebral body.
      Dissection begun over the disc is less likely to cause bleeding. Make a
      radiograph at this point to verify the level. After the parietal pleura
      is opened, it may be sutured back on itself laterally with two stay
    • Separate, sever, and ligate each of the
      intercostal vessels over the vertebral body. If a large paravertebral
      abscess is present, the arteries enter the abscess. Take care to avoid
      clamping segmental arteries too close to the aorta so as to lose the
      tie or too close to the intervertebral foramen. Tie arteries and veins
      separately or together, depending on their size. Pass a right-angled
      clamp under the vessels, and use a braided 2-0 suture in a free tie to
      tie off first the medial and then the lateral exposed vessels; use
      vascular clamps in a similar fashion.
    • Caution: Take care
      to dissect adequately under the vessels. A common mistake is to have
      both ligature sutures in the same place under the vessel and not have
      adequate room for cutting between them. Handle every segmental vessel
      in the area of where bony work will be done in this manner. Paralysis
      due to ligation of a segmental artery on the vertebral body has not
      been a problem
    • Caution: Do not dissect into the intervertebral foramen.
    • Bluntly expose the outer surface of the
      spine after division of the segmental vessels. When bone and disc
      exposure is needed, cut with the cautery directly to bone. Use the
      periosteal elevator to dissect the annulus off the disc and the
      periosteum off the bone medially and laterally, exposing the entire
      disc and vertebral column. The tendency is not to dissect the soft
      tissue laterally enough off the spine. The rib head articulates with
      the cephalad half of its appropriate vertebral body and the disc space
      above. Access to the posterior disc and spinal column can be gained by
      resecting the rib head (Fig. 138.14). Removal
      of the head of the rib and its articulation allows excellent exposure
      of the posterolateral aspect of the intervertebral disc. After the rib
      head and disc are removed, identify the intercostal nerve, dural sac,
      posterior vertebral body wall, and spinal canal. The costal vertebral
      articulation is a major stabilizing structure in the thoracic spine.
      Identifying the left pedicle in a left-sided approach helps locate the
      spinal canal for orientation. The vertebral body can be completely
      exposed by resecting the disc above and below to identify the posterior
      body wall and spinal canal and dissected laterally to identify the
      pedicle and spinal canal.
      Figure 138.14.
      The rib articulates with the cephalad half of its appropriate numbered
      vertebral body and with the disc space above. Therefore, the tenth rib
      articulates at T9–T10.
    • Visualize the lung fully expanded in all
      areas before closure. Close the parietal pleura over the spine whenever
      possible. Place the chest tube through a separate aperture, preferably
      in the ninth intercostal space. Protect the lung during closure. Close
      the chest with the rib approximator. Close the rib bed with interrupted


      braided Dacron sutures. The chest tube connects to the water seal. With
      the lung re-expanded, the chest tube can usually be removed within 48
      to 72 hours, depending on drainage and expansion of the lung.

The rules for resecting the best rib for exposure of the
thoracolumbar junction are much the same as in the rest of the thoracic
spine. Hodgson and Rau (13,14) recommend a ninth rib resection for T10–L1. Dwyer et al. (6)
recommend a tenth rib resection with the standard thoracolumbar
approach for the T10–L1 area. For exposure of the T12–L1 area, Perry (19)
recommends a tenth rib resection. Ideally, choosing the rib in the
midaxillary line opposite the lesion or the apex of a curve allows
adequate proximal exposure for working “down” or caudad on the lesion.
Transthoracic resection of the ninth rib is usually best
for maximum exposure of T11–T12. A tenth rib thoracoabdominal approach
is preferred for exposure of the T12–L1 area. Both techniques involve
detaching the diaphragm at its circumference. A twelfth rib approach is
used in cases in which less exposure is needed or when it is imperative
that the diaphragm not be taken down. A twelfth rib extrapleural
retroperitoneal approach is recommended for exposure of L1–L2.
The approach through the eleventh rib, a more demanding
approach with less expansive exposure, is the highest practical,
extrapleural, retroperitoneal anterior approach for the exposure of the
T10–L2 area. It is ideally used in severely ill patients in whom
avoiding opening the pleural cavity and cutting the diaphragm is an
advantage. Another alternative for limited extrapleural exposure with
low morbidity is the posterior costotransversectomy approach. The
vertebral body and spinal canal can be exposed by following the twelfth
subcostal nerve to T12–L1. Unless at least two levels are exposed with
the approach, the visualization necessary to perform total discectomy,
vertebrectomy, and strut grafting is extremely poor compared with the
anterior approach.
A third approach that may be used in special situations
is the tenth rib thoracolumbar approach for long exposures of the
thoracic and lumbar spine. This approach allows proximal and distal
extension for multilevel operations and optimum exposure for bony work.
  • Place the patient in the lateral
    decubitus position. Make the approach from the convexity of the
    scoliosis or from the left side, when possible (Fig. 138.15).
    A left-sided approach is preferred because of ease of mobilization of
    the aorta compared with the vena cava and because splenic retraction is
    easier than hepatic reconstruction. Open the skin and subcutaneous
    tissue from the lateral


    border of the paraspinous musculature over the tenth rib to the junction of the tenth rib and costal cartilage (20).
    Curve the incision anteriorly from the tip of the tenth rib to the
    lateral rectus sheath and distally down the edge of the sheath as far
    as necessary for exposure. Use electrocautery to slowly extend the
    incision through each muscle layer while an assistant aggressively
    picks up bleeders with two Adson forceps.

    Figure 138.15. Skin incision for a tenth rib thoracoabdominal approach.
  • Open the superficial periosteum of the
    tenth rib to the costal cartilage. Use the sharp, curved periosteal
    elevator to remove the superficial and deep periosteum off the rib.
    Take care to avoid the neurovascular bundle on the inferior surface of
    the rib. Cut posteriorly at the angle of the rib, and cut at the
    junction of the rib and costal cartilage. Remove the rib. On opening
    the pleural space, retract the lung and fully open the rib bed with
    scissors (Fig. 138.16). At this point, the intrapleural cavity is opened and the retroperitoneal cavity is still closed.
    Figure 138.16. With the rib removed, carefully delineate the costal cartilage.
  • Split the costal cartilage with a knife
    along its length. Open the undersurface of the costal cartilage and
    retract the two tags of cartilage (5,6,20) (Fig. 138.17).
    Figure 138.17.
    Split the costal cartilage. Open the most superficial layer of soft
    tissue under the costal cartilage enough to allow retraction of the
    cartilage tips.
  • Identify the peritoneum and
    retroperitoneal space by blunt dissection under the retracted split
    tips of the costal cartilage. The guide to the retroperitoneal space is
    the light areolar tissue of the retroperitoneal fat (Fig. 138.18).
    Figure 138.18.
    Retract the split tips of costal cartilage. Identify the insertion of
    the diaphragm into the cephalad cartilage tip and the insertion of the
    abdominal musculature into the caudad cartilage tip.
  • Bluntly dissect the peritoneum off the inferior surface of the diaphragm (Fig. 138.19).
    The peritoneum is swept, using a sponge, first from the undersurface of
    the diaphragm, then from the transversalis fascia, and finally from the
    abdominal wall.
    Figure 138.19. Bluntly dissect the periosteum off the inferior surface of the diaphragm.
  • After the peritoneum is retracted,
    carefully open the abdominal musculature (the external oblique, the
    internal oblique, and the transversus abdominis) one layer at a time,
    with complete hemostasis. At this point the chest and retroperitoneal
    space are open and the diaphragm is the intervening structure in the
  • Incise the diaphragm from inside the
    chest with clear visualization under the diaphragm in the
    retroperitoneal space. Extend the incision in the diaphragm
    circumferentially, 1 inch from its peripheral attachment to the chest
    wall (28). Use marker clips throughout the take-down of the diaphragm to allow accurate reapproximation.
  • P.3648

  • For work on T2–L1, resect the diaphragm
    to the spine. Cut the crus of the diaphragm and elevate it off the
    spinal column. Use protected Deaver retractors to retract the
    peritoneal sac anteriorly. Identify the psoas muscle with its most
    cephalad attachment to the transverse process of L, and protect the
    muscle because the lumbosacra plexus is under it. With a large rib
    retractor, such as the Feochetti, open the tenth rib incision in the
    chest. The spine will be visualized from approximately T-6 as far
    distally in the lumbar spine as necessary. In the lumbar spine, remove
    the crus of the diaphragm and the attachments of the psoas muscle, if
    needed, for proper visualization of the spine. In the thoracic spine,
    the parietal pleura is opened as in a standard thoracotomy approach.
    Tie and ligate the intercostal artery and vein to allow mobilization of
    the major vascular trunks. If it is identified as in the operative
    area, the thoracic duct, which usually crosses right to left around
    T4–T5, is tied off. Avoid the sympathetic plexus. After the intercostal
    vessels are removed, cut directly to the spine. Dissection is carried
    out on the spine, and soft tissue is removed laterally.
  • The key to closure is the reapproximation
    of the costal cartilage. After the diaphragm is resutured with multiple
    interrupted sutures and the split cartilage is reapproximated, insert
    the chest tube in the eighth intercostal


    and pass it posterosuperiorly. Attached to the cephalad half of the
    costal cartilage is the insertion of the diaphragm and the
    interthoracic fascia. Inserting into the distal split of costal
    cartilage is the transverse abdominal fascia and attachment for the
    abdominal musculature. With the costal cartilage reapproximated, the
    layers of the abdominal musculature are better defined. Close each
    layer of the abdominal wall separately when possible, and close the
    chest as in a standard thoracotomy.

  • Position the patient supine on the table with the lower lumbar spine at the level of the kidney rests.
  • Make a lower abdominal pararectus
    incision through the skin and subcutaneous tissue. The most immediate
    layers are those of the external oblique with its transition into the
    linea semilunaris, which leads to the fascia of the rectus sheath. The
    linea semilunaris is composed of the aponeurosis of the three layers of
    the abdominal musculature and their fascia.
  • Incise the fibers of the external
    oblique, the internal oblique, and the small thin layer of transversus
    abdominis muscles laterally to the semilunaris in line with the skin
  • Identify the transversalis fascia, which
    is the internal investing fascial layer of the abdominal cavity.
    Dissect the outer surface of the transversalis fascia to the edge of
    the rectus sheath. The transversalis fascia splits at this point to
    form the lamina of the rectus sheath. The posterior lamina of the
    rectus sheath forms the endoabdominal fascia in this area.
  • Carefully incise the transversalis fascia laterally to the linea semilunaris, and identify the peritoneum through the incision.
  • Begin the incision in line with the skin
    incision. Dissect the peritoneum with a sponge or gloved hand off the
    undersurface of the transversalis fascia. Open the abdominal wall after
    the peritoneum has been identified and cleared.
  • Bluntly dissect the peritoneum from the
    lateral abdominal wall, progressing posteriorly. Identify the psoas
    muscle, as in any retroperitoneal approach to the spine. Retract the
    peritoneum off the left iliac artery and vein by use of the surgeon’s
    hand, a padded deaver retractor, or sponge sticks. Sweep the peritoneum
    with the ureter from left to right, and expose the left common iliac
    artery and vein. Insert Freebody pins or special retractors.
  • Palpate and identify the intervertebral
    disc. Remember that this is a relatively avascular area. With any
    approach to the L4–S1 area, identify the left iliolumbar vein and
    ligate it when necessary. Dissection within the bifurcation of the
    aorta should be blunt and as avascular as possible. Remember, the left
    common iliac vein lies in the bifurcation over the L4–S1 disc. The
    variation in inferior vena cava and lumbar veins often dictates the
    exact approach from this point.
  • Bluntly retract and protect the hypogastric plexus.
  • Allowing the peritoneal sac to fall into
    place, close the muscle layers with a running suture. The transversus
    abdominis and the internal oblique may be closed together.
For the retroperitoneal exposure of the lumbar spine, an
anterior pararectus vertical incision, a J-shaped renal incision, or a
horizontal lateral abdominal incision can be used (Fig. 138.20). I prefer the horizontal oblique incision.
Figure 138.20.
For retroperitoneal exposure of the lumbar spine, an anterior
pararectus vertical incision, a J-shaped renal incision, or a
horizontal lateral abdominal incision can be used.
  • Place the patient in the supine position
    over the kidney rests. For patients with a large abdominal pannus, the
    left lateral decubitus position can be used. In the lateral position,
    too much hip flexion at this point will limit the operative exposure
  • Start the incision equidistant between
    the lowest rib and the superior iliac crest in the midaxillary line,
    and extend it approximately to the edge of the rectus sheath. The level
    of the incision varies according to the level of the spine approached:
    L5–S1 is in the lower half of the distance between umbilicus and
    symphysis, L4–5 is in the upper half, L3–4 is at the umbilicus, and
    L2–3 is above the umbilicus. The length of the incision can vary
    according to the surgeon’s experience, the exposure needed, and the
    operation to be done.
  • Muscle relaxation allows greater mobility to the abdominal


    wall and decreases the contractility of the muscle as it is incised.
    First, open the muscle layers as laterally as possible because they are
    thicker here and there is less chance of penetrating the peritoneum.
    The muscle layers thin out, and the layers of the fascia become almost
    joined medially. The peritoneum is very superficial. Inadvertent
    penetration of the peritoneum is most likely just lateral to the rectus
    sheath. Dissect through the external oblique and the internal oblique
    muscle. Inferior to the internal oblique is the transversus abdominis.
    Use care in inserting self-retaining retractors into the muscle layers
    so as not to damage the peritoneum. Often, the transversus abdominis
    muscle is a very thin or absent muscle layer. Bluntly spread this thin
    muscle in line with its fibers to expose the transversalis fascia.

  • Open the transversalis fascia in the lateral portion of the wound (Fig. 138.21).
    Lift the transversalis fascia with Adson forceps and carefully open it
    with blunt scissors. The retroperitoneal fat allows room to enter the
    extraperitoneal space.
    Figure 138.21.
    Open the transversalis fascia in the lateral portion of the wound. Lift
    it with Adson forceps and carefully open it with blunt scissors.
  • Enter the retroperitoneal space
    laterally. Identify the peritoneum and the fat of the peritoneal space.
    Remove the peritoneum from the remaining transversalis fascia with
    blunt dissection. Extend the incision after the peritoneum has been
    safely removed. The sheath may be incised for added exposure. Torn
    peritoneum should be repaired promptly (19).
  • Identification of the psoas muscle is the
    key to the retroperitoneal approach. Pass your hand directly to the
    psoas. Avoid opening the retropsoas space, which is a blind pouch. The
    genitofemoral nerve can be identified on the psoas. The spine is
    immediately medial to the psoas and can be partially obscured by it.
    Palpate and identify the psoas muscle, the intervertebral disc, the
    aorta, and the vertebral body. The paravertebral sympathetic chain lies
    medial to the psoas muscle. The ureter will be reflected medially with
    the undersurface of the peritoneum. If a retroperitoneal abscess is
    well developed, open it and dissect inside the abscess to the spine.
  • The key at this point is to identify the
    raised, white, softer disc by direct palpation with the finger, as
    opposed to the lower, concave vertebral body, where the lumbar vessels
    are found. The discs are the hills, and the vertebral bodies are the
    valleys. The vessels are in the valleys.
  • Once the lumbar disc can be identified,
    insert a blunt elevator or padded small retractor to sweep the soft
    tissue from left to right across the disc space. The lumbar veins are a
    horizontal tether. Variations in formation of the inferior vena cava
    and lumbar veins are the rule rather than the exception (11).
    The most important of these veins is the iliolumbar vein, which crosses
    the body of L-5 from right to left and ascends in the left paraspinous
    area (13). This vessel is a direct tether to the left-to-right retraction of the aorta off the spine and is very vulnerable to avulsion.
  • For operations on the L4–L5 disc space, identify the iliolumbar vein early in the dissection (Fig. 138.22).
    Ligate it after clamping the vein with angled tonsil clamps and passing
    two or three ligatures around the vein. These ligatures should not be
    tied too close to the vena cava because a sidewall injury can occur.
    Transect the vein after securing the permanent ties. Greater
    mobilization of the vena cava and venous structures, left to right, is
    thereby obtained. The iliolumbar vein consistently requires ligation.
    Figure 138.22. For operations on the L4–L5 disc space, identify the iliolumbar vein early in the dissection.
  • Lumbar veins of varying sizes at various
    positions are always present. Some may be directly posterior to the
    vena cava and of quite large diameter. Dissection on the anterior spine
    consists of gentle stretching and pulling of the structures, blunt
    dissection, direct pressure over many small bleeding areas with a
    sponge, and a minimum of electrocautery. The paraspinous sympathetic
    plexus between the spine and the psoas muscle


    in size and number of fibers. Branches course between the preaortic and
    paraspinous chains. Preserve paraspinous sympathetic fibers that do not
    impede dissection.

  • Dissect with the fingertip and blunt
    elevators all the vascular structures from left to right to give
    adequate visualization of the end plate of the vertebral body above the
    disc (27).
  • Use malleable Deaver-type retractors or
    blade spike retractors around the disc space. Alternatively, prepare
    four Freebody Steinmann pin retractors with rubber sleeves and mount
    them in a Steinmann pin holder (9). For any
    sharp stay-retractor that is driven into the body, stabilize the pin on
    the finger and engage the tip into the vertebral body under direct
    vision. The assistant taps the pin into the body while the surgeon
    maintains control of the pin. Avoid the tendency for the pin to enter
    the disc space by directing the tip of the pin horizontal to the disc
    space. Allow a sufficient distance from the endplate to allow work on
    the disc space without dislodging the pin. Place the superior and
    inferior right-sided pins before placing the left-sided pins.
  • Expose the annulus of the disc (Fig. 138.23).
    There should have been minimal sharp dissection and cautery in this
    area. Now prepare the disc for the operative procedure. The vena cava
    and iliac artery and vein are held by the retractors.
    Figure 138.23. Expose the annulus of the disc.
  • Special curved or malleable retractors can be used between the stay retractors for protection of the vena cava.
  • Extract the retractors with the same
    amount of care as when they were inserted. The sheath and a finger must
    guard the tip; otherwise the vena cava will be torn as the sharp tip
    passes the vessel that is tented around it.
  • Remember:
    • When making the incision, follow the skin guidelines for optimum spine exposure.
    • Achieve careful hemostasis in the muscle layers.
    • Incise the transversus abdominus muscle layer and the transversalis fascia in the lateral portion of the wound.
    • Beware of thinning muscle layers and the peritoneum’s superficial position medially near the rectus sheath.
    • Pass directly to the psoas muscle.
    • Identify the raised, soft, white disc.
    • Identify, ligate, and divide the iliolumbar vein.
    • Sweep prevertebral tissue left to right across the disc.
    • Insert the Steinmann pin after placing it directly on bone with the fingertip.
    • Retract the Steinmann pin, again with the fingertip preventing the tip of the pin from damaging the left iliac artery.
  • Palpate the spine with a finger and find
    a disc for orientation. Usually, it is the L4–L5 disc. With
    identification of the L4–L5 disc, palpate the pulse of the left common
    iliac artery and the aortic bifurcation. The bifurcation of the aorta
    is critical in determining the exact approach


    from this point. The usual bifurcation at the L4–L5 disc level was present in 69% of anatomic dissections performed by Harmon (11), but great variation exists.

  • Palpate the left common iliac artery and
    pass over it medially to the L5–S1 disc. By placement of the finger and
    a subsequent blunt retractor such as a sponge-covered elevator, develop
    a plane just to the right of the left common iliac artery.
  • The left iliac vein lies within the
    aortic bifurcation. It often courses directly on the surface of the
    L5–S1 disc and may be flattened against the disc or L-5 body, with its
    venous character obscured. Mobilize it to the left and cephalad with
    the left iliac artery.
  • The middle sacral artery and veins are
    present in the bifurcation. The key to handling these structures is
    blunt dissection just to the right of the left common iliac artery,
    sweeping from left to right the prevertebral tissue, including the
    middle sacral vessels and superior hypogastric plexus, off the
    lumbosacral disc. Occasionally, the middle sacral vessels are of
    formidable size, but seldom do they have to be ligated (4).
  • An additional structure in the bifurcation is the superior hypogastric sympathetic plexus.
  • The thoracolumbar sympathetic chain
    extends down anterior to the aorta and vertebral bodies in the
    retroperitoneal space as the preaortic sympathetic plexus. At
    approximately the L3–L4 level, the inferior hypogastric plexus extends
    to L4–S1 as the superior hypogastric plexus (Fig. 138.24).
    The structure of the superior hypogastric plexus varies considerably
    because the preponderance of the superior hypogastric plexus fibers is
    usually closer to the left iliac artery as they arch over the L5–S1
    disc in the bifurcation of the aorta (Fig. 138.25) (16).
    There may be multiple strands or one predominant large simple nerve
    trunk. The superior hypogastric plexus contains the sympathetic
    function for the urogenital system. The S1–S4 nerve roots that
    contribute to the pelvic splenic nerves provide parasympathetic
    function for the urogenital system. The pudendal nerve covers somatic
    function from S-1, S-2, S-3, and S-4.
    Figure 138.24.
    Sweep the prevertebral tissue bluntly off the front of the L5–S1 disc.
    The superior hypogastric plexus may be a diffuse plexiform nerve
    formation that is retracted with the other tissue, or it can be a
    discrete well-defined presacral nerve.
    Figure 138.25. The superior hypogastric plexus is within the bifurcation of the aorta.
  • Ejaculation is predominantly a
    sympathetic function, whereas through control of the vasculature of the
    penis, erection is predominantly a parasympathetic function. Retrograde
    ejaculation and sterility result from disruption to the sympathetic
    plexus. The main effect of damage to the superior hypogastric plexus is
    improper closing of the bladder neck, with resultant retrograde
    ejaculation, although the sympathetic fibers also have some effect on
    the motility of the vas deferens, which is important in the
    transportation of the spermatozoa from the epididymis to the seminal
    vesicle (15).
  • The prognosis for recovery from retrograde ejaculation is good (8).
    Sperm can be obtained in refractory cases by bladder aspiration
    techniques. Damage to the superior hypogastric plexus should not
    produce impotence or failure of erection. Avoid damaging the
    hypogastric plexus by doing the following (4):
    • For the transperitoneal midline approach,
      carefully open the posterior peritoneum and bluntly dissect the
      prevertebral tissue from left to right (9).
    • Visualize and retract the prevertebral
      tissues by opening the posterior peritoneum higher over the bifurcation
      and then extending the opening down over the sacral promontory (4,8,9,15).
    • P.3653

    • Remove the prevertebral tissue from the L5–S1 disc with blunt dissection, retraction, and spreading.
    • Attempt to retract the middle sacral
      artery and vein without electrocautery by spreading and blunt
      dissection. Use vascular clips or tie ligation when this vessel is of
      considerable size.
    • Until the annulus of the disc is clearly exposed, make no transverse scalpel cuts on the front of the L5–S1 disc.
    • Do not use electrocautery within the aortic bifurcation.
  • The key to avoid damaging the superior
    hypogastric plexus is to avoid transverse cuts on the face of the disc
    until all the prevertebral tissue has been elevated from the annulus
    and to avoid electrocautery on the surface of the L5–S1 disc. Small
    bleeding points are encountered when doing this dissection, but they
    are usually easily controlled by direct finger pressure or packing with
    hemostatic gauze. Usually, the left iliac artery and vein will be
    retracted to the left, but it may require retraction to the right on
  • Locate and ligate the iliolumbar vein before any mobilization of the left iliac artery to the right.
  • Always obtain radiographic confirmation
    of the level. It can be done easily by inserting a #22-gauge spinal
    needle and taking a radiograph. Because the L5–S1 disc and the sacrum
    are often angled very horizontally, the body of L-5 can be mistaken for
    the sacrum.
  • Insert appropriate Freebody Steinmann pin stay-retractors, blade-point retractors, or hand-held retractors.
  • For the transperitoneal exposure, use
    either a vertical midline incision or a transverse “smile” incision.
    The “smile” is better cosmetically and gives excellent exposure, but it
    requires transection of the rectus abdominus sheath. Identify and open
    the rectus sheath, and transect the rectus abdominus muscle. The
    posterior rectus sheath, the abdominal fascia, and the peritoneum are
    conjoined in this area. Carefully open the posterior rectus sheath and
    abdominal fascia to the peritoneum.
  • Pick up the peritoneum. Open the length of the wound carefully, avoiding damage to the bowel. Identify the


    posterior peritoneum over the sacral promontory after packing off the bowel.

  • Palpate the aorta and both iliac vessels through the posterior peritoneum. Feel the softer texture of the L5–S1 disc.
  • Inject the retroperitoneal space with saline to achieve separation of the peritoneum from the vascular structures.
  • Pick up the peritoneum with Adson forceps; handle it delicately.
  • Avoid use of the electrocautery anterior
    to L5–S1 to prevent damage to the superior hypogastric plexus, despite
    the fact that there is bleeding in this area. The left common iliac
    vein often lies as a flat, white, bloodless ribbon across the L5–S1
    disc within the aortic bifurcation.
  • After the left common iliac artery and
    left common iliac vein are identified, use blunt dissection to the
    right of the left iliac artery and hypogastric plexus and soft tissue,
    moving from left to right (Fig. 138.26).
    Figure 138.26. Exposure of the L5–S1 disc. See text for a description of the technique.
  • Bluntly dissect the middle sacral artery
    and vein from left to right without sacrifice at this point.
    Longitudinal blunt dissection allows better mobilization of these
    vascular structures. When bleeding is encountered, use direct finger
    and sponge pressure for a short time, followed by blunt dissection.
    Control hemorrhage with packing and pressure. Divide and tie the middle
    sacral artery and vein, if necessary.
  • Position the patient to allow full chest
    excursion, to maintain the neck in a safe position, and to allow the
    abdomen to hang completely free of pressure. Flex the hips and knees
    enough to relieve nerve root tension but not so much as to obstruct
    arterial flow to the legs or to produce any abdominal pressure. I
    prefer the Andrews frame.
  • Obtain a skin marker radiograph by
    inserting two #20-gauge spinal needles perpendicular to the skin
    approximately three fingerbreadths lateral to the spine. Using the
    alignment of the needles, put the skin incision in the midline over the
    disc space. Paraspinous needles allow a more accurate skin incision
    than a spinous process marker.
  • Use a skin marking pencil to draw a
    vertical, midline skin incision relative to the two needles over the
    disc space. Make a dermal skin incision only. The average length is 3.2
    cm for a one-level microscopic discectomy, longer for a more extensive
    decompression. Inject 25 to 50 ml 1:500,000 epinephrine through the
    dermal incision into the subcuticular tissue and directly down to the
    lamina into the paraspinous muscle mass. Cut with a scalpel directly to
    the fascial layer. Preserve the lumbodorsal fascial attachments to the
    spinous process, the interspinous ligament, and the supraspinous
    ligaments by making a paraspinous fascial incision that can be sutured
    at closure without tension. This is preferable to removing all
    soft-tissue fascial attachments from the spinous process, unless a
    total laminectomy is to be done, in which the fascia is totally removed
    from the spinous process and lamina with the electrocautery.
  • The lumbodorsal fascia is critical for
    stability of the spine. Maintaining the fascial attachments to the
    spine is important and should be done when possible. The abdominal,
    trunk, and gluteal muscles contract and tense the lumbodorsal fascia;
    the fascia attachment to the spine allows these muscles to stabilize
    the spine.
  • Make an incision into the lumbodorsal
    fascia just lateral to the bulbous tips of the spinous processes.
    Lengthen the fascial incision. Insert a Cobb elevator, with the tip
    turned upward, onto the spinous process just under its bulbous tip, and
    start the subperiosteal dissection. Then turn the elevator bevel down.
    Dissect, identify by touch the cephalad and then the caudad lamina, and
    clear the interlaminar area. Take care not to cut through the outer
    cortex of the lamina. Sweep the superficial soft tissue off the
    interlaminar area laterally out to the facet joint capsule. Do not
    damage the capsule. Protect the facet joint capsule. Remember that the
    two laminae and their interlaminar areas are the only areas that need
    be exposed for an operation on one intervertebral disc.
  • P.3655

  • Following exposure of the intralaminar
    area, place a Williams self-retaining retractor with the blade
    retracting laterally over the facet joint capsule with the pointed tip
    placed medially. For larger, bilateral exposures, I use the Wiltse
    retractors with both sides exposed similarly.
  • The superficial ligamentum flavum blends
    laterally into the facet joint capsule. Incise the superficial
    ligamentum flavum with the #15 blade or electrocautery laterally or at
    the junction of the superficial ligamentum flavum and the facet joint
    capsule. Use a curet to elevate the superficial ligamentum flavum from
    the deep ligament moving from lateral to medial. Remove the superficial
    ligament with a pituitary rongeur. The vertical striations of the
    yellow deep ligamentum flavum can be seen in the depths of the
    interlaminar area. Use an angled curet to clear under the caudal edge
    of the cephalad lamina and a straight curet to define the ligamentum
    flavum attachment to the caudad lamina (Fig. 138.27). Expose the deep portion of the ligamentum flavum’s vertical striations.
    Figure 138.27.
    This underview of the posterior elements from the intervertebral canal
    demonstrates the ligamentum flavum and its insertion on the lamina.
  • Several factors concerning the anatomy of the ligamentum flavum are important:
    • It has a deep and superficial portion.
    • It blends with the facet joint capsule laterally.
    • It inserts over the caudal 50% of the undersurface of the cephalad lamina.
    • It inserts on the cephalad edge of the caudad lamina.
    • Its undersurface is the ideal dural covering.
    • It has a vertical, parasagittal
      orientation deep in the lateral recess under the superior facet that
      may contribute to lateral recess stenosis.
    • It is the main stabilizing ligament of
      the posterior column, and preservation of as much of it as possible
      will benefit spine stability at that motion segment.
    • It is the soft-tissue roof of the intervertebral foramina.
  • Perform as much of the lateral wall
    resection and laminectomy as possible before opening the ligamentum
    flavum. Estimate the size of the interlaminar area that will be needed
    for correcting the pathologic process. A portion of the caudad edge of
    the cephalad lamina can be removed if it is believed that exploration
    of the spinal canal will require greater cephalad exposure. The walls
    of the interlaminar area may be the area to be removed. Progressing
    from dorsal to ventral, the lateral wall of the interlaminar area is
    composed of the facet joint capsule, the inferior facet, the
    intra-articular space of the facet joint, the superior facet, the deep
    capsule and ligamentum flavum, the nerve root, the blood vessels, and
    the floor of the canal. The preoperative CT scan should determine the
    amount of lateral recess stenosis and how much of a medial facetectomy
    is needed. Remove as much bone as necessary. For a standard L5–S1
    discectomy, I seldom remove any bone. At L3–L4, a centimeter of
    cephalad lamina is often removed. Evaluate the CT scan for cephalad
    migration of a disc fragment that would require the removal of more
    lamina. To allow a more lateral approach to a larger extruded disc
    fragment, remove a small portion of the medial facet. More extensive
    exposure may be required depending on the pathology.
  • P.3656

  • For a discectomy, make an incision with a
    #15 blade into the deep portion of the ligamentum flavum, approximately
    50% of the width of the interlaminar area. Incise the ligamentum flavum
    by feathering the knife blade, allowing one to see the edge of the
    knife cutting into the ligamentum flavum. Make the incision by long
    cuts into the ligamentum flavum reaching from lamina to lamina with
    careful observation for any sign of the white undersurface of the
    ligamentum flavum, followed by the bluish hue of the dura. Once the
    undersurface is reached, use the handle of the knife or a Penfield 4
    elevator to open the last few underlayers of the ligamentum flavum. Use
    the Penfield 4 elevator to separate the entire length of the ligamentum
    flavum. Under the ligamentum flavum is usually a layer of epidural fat
    over the dura, but with a large space-occupying lesion in the canal,
    the dura may be immediately adjacent to the undersurface of the
    ligamentum flavum. Pass the Penfield 4 elevator under the lateral leaf
    of the ligamentum flavum, and retract the dura medially away from the
    lateral leaf of the ligamentum flavum. A cottonoid can be placed under
    the lateral leaf of the ligamentum flavum. With a Kerrison rongeur
    angled 40° in the dominant hand and the Penfield 4 elevator in the
    other hand, pass the Kerrison rongeur under the lateral ligamentum
    flavum and remove the lateral ligamentum flavum.
  • The epidural fat, the dura, the nerve
    root, and the longitudinal blood vessels in the lateral recess can
    usually be identified after the lateral half of the ligamentum flavum
    is removed. The deep portion of the ligamentum flavum runs vertically
    in the lateral recess and attaches to the facet joint capsule. Position
    the cottonoid or Penfield 4 elevator between this portion of the
    ligament and the underlying nerve root. This stage of entering the
    canal is often an anxious one because of fear of bleeding and damaging
    the nerve root. The more delicate the approach, the less bone that is
    cut, and the less vigorous the removal of the lateral ligamentum
    flavum, the less bleeding there will be. Magnification is of tremendous
    value in identifying vessels and allowing safe, accurate retraction and
    bipolar coagulation, if needed. Removal of fat causes bleeding and
    later scarring. Bleeding often starts when exposing the disc or nerve
    root. When lateral exposure is obtained out to the pedicle, the
    longitudinal vessels lateral to the root can be identified and
    cauterized with the bipolar cautery. Cottonoids placed laterally at the
    cephalad and caudad extremes of the exposure can collapse the vessels
    and allow work in the area between the cottonoids.
  • A transverse or horizontal vascular
    supply exits each intervertebral foramen. The most consistent vascular
    leash is found just caudad to the nerve root exiting in the caudal
    portion of the intervertebral foramen at the cephalad portion of the
    disc. For large exposures, when the dural sac needs to be retracted to
    the midline, identify and coagulate the vascular leash with a bipolar
    cautery. Minimize the use of electrocautery because the more that is
    used, the more scarring there will be. The use of cottonoids, Surgicel,
    and thrombin-soaked Gelfoam retards bleeding. I prefer not to leave
    Gelfoam and Surgicel packing in the spinal canal. Cottonoids remove
    epidural fat and should be used judiciously.
  • The surgeon needs to know where the disc and root are without undue exploration. The key to intracanal anatomy is the pedicle (Fig. 138.28).
    The pedicle is deep to the caudad third of the inferior facet. After
    the ligamentum flavum is removed, palpate into the canal with a nerve
    hook or dental tool. Often, the pedicle is lateral


    an overhanging roof of superior facet. In fact, the superior facet may
    be mistaken for the pedicle. To remove the roof of the lateral recess
    and to relieve lateral recess stenosis, remove the facet joint with the
    Kerrison rongeur medially to the parasagittal plane of the medial
    border of the pedicle.

    Figure 138.28.
    The pedicle is the key to the intracanal anatomy. Identification of the
    pedicle will lead to the location of the disc and nerve root.
  • Knowing the location of the pedicle tells you the following:
    • The disc space is less than 1 cm cephalad to the pedicle. It often appears to be immediately cephalad adjacent to the pedicle.
    • The intervertebral foramen above the
      pedicle is for the exiting nerve root and the intervertebral foramen
      below the pedicle is the foramen for the transversing nerve root.
    • Dorsal and immediately cephalad to the
      pedicle is the superior facet. The superior facet is the roof of the
      intervertebral foramen for the exiting nerve root.
    • Just medial to the pedicle is the traversing nerve root.
  • Extensive probing should not be done in
    the medial pedicular area because the pedicular plexus will bleed.
    Remember, at higher lumbar levels, the disc is farther cephalad
    relative to the interlaminar space. Therefore, the L5–S1 disc is
    approximately at the level of the interlaminar space between L-5 and
    S-1. The L2–L3 disc space is well cephalad under the lamina of L-2
    rather than at the level of the interlaminar space between L-2 and L-3.
    The ligamentum flavum covers the interlaminar area.
  • Often, it is imperative to expose the
    disc space. The disc is a raised, white, soft structure that may be
    covered by epidural fat, veins, and the nerve root. Feel for the disc
    using the Penfield 4 elevator. It causes little bleeding and allows for
    palpation of the disc with the tip of the instrument. Reach out
    laterally and feel for the floor of the canal. Gently retract medially
    with the Penfield 4 elevator. Feel for obstruction to this medial
    retraction. Do not retract against a major obstruction. Retract gently,
    and insert the microsucker retractor. Lift the root up and medial with
    the nondominant hand; expose the disc with the Penfield 4 elevator in
    the dominant hand.
  • When there is difficulty in finding the
    disc or retracting the nerve root, several methods have been used to
    prevent damage to the nerve root. Knowing the location of the pedicle
    in the canal is probably the most significant way to avoid major damage
    to the nerve root. Find the pedicle. The transversing nerve root is
    adjacent medially to the pedicle. Identify the nerve root medial to the
    pedicle. If the root cannot be retracted because it is tightly against
    the medial wall of the pedicle, proceed cephalad to a point slightly
    lateral to the medial wall of the pedicle. The transversing nerve root
    should not be lateral to the medial wall of the pedicle. Exposing the
    disc cephalad to the pedicle and lateral to the medial wall of the
    pedicle can avoid nerve damage. The nerve root exiting in this
    intervertebral foramen cephalad to the pedicle will usually be further
    cephalad, just under the pedicle above. The exiting nerve root runs
    obliquely across the intervertebral disc laterally in or lateral to the
    intervertebral foremen. The farther lateral on the intervertebral disc,
    the more likely the cephalad exiting nerve root is reached. A lateral
    disc herniation may trap the exiting nerve root in the intervertebral
    foramen. A conjoined root may totally fill the entire foramen from
    pedicle to pedicle. An exiting conjoined nerve root limits exposure of
    the disc. It can usually be identified preoperatively on the myelogram
    and contrast CT scan. The key to avoiding damage to a conjoined nerve
    root is recognition. This is facilitated by lateral exposure of the
    traversing root shoulder.
  • For further exposure of the disc,
    determine the amount of tension in the nerve root. Do not retract the
    root against a solid obstruction. If it can be retracted easily,
    retract it medially with the nerve root retractor. If it is tight, it
    will feel like you are retracting against a solid wall.
    There are five common methods of dealing with a tight nerve root:
    • Explore the axilla of the transversing
      root with the Penfield 4 elevator. The axilla is in the caudal part of
      the exposure between the root and the dural sac. If a fragment is
      found, remove it with the nerve hook. Bleeding may be encountered.
    • Obtain more lateral exposure. Be sure you
      have identified the pedicle and have exposure lateral to the medial
      wall of the pedicle. The traversing nerve root should not be lateral to
      the medial wall of the pedicle.
    • Enter the disc space lateral to the root,
      and try to decompress the disc and pull disc material from under the
      root through the disc space.
    • Be sure that the root is free cephalad to
      the disc and that the ligamentum flavum or undersurface of the cephalad
      lamina is not a factor. Remove enough lamina and ligament cephalad to
      expose the shoulder of the nerve root.
    • The nerve root may be tethered caudally
      in the foramen below the pedicle. Remove the roof (the junction of the
      caudad lamina and the superior facet) over the transversing root as it
      exits around the pedicle. A foraminotomy of the foramen below may allow
      better retraction of the root.
  • Gently lift and retract the nerve root
    with a sucker retractor in the nondominant hand and explore the disc
    area with a nerve hook in the dominant hand. Take great care not to
    stretch the nerve root. Exploration underneath the dural sac may reveal
    a large fragment


    herniated disc that can be pulled out from under the nerve root with
    the nerve hook. The lateral exposure allows this fragment of disc to be
    pulled laterally rather than vertically. Removing the fragment
    laterally from under the nerve root will decrease the nerve root
    tension and allow better visibility and protection for the nerve root.
    Large dilated vessels often decrease in size and not bleed when the
    fragment is removed, relieving vascular distention.

  • Expose the annulus with the Penfield 4
    elevator. Determine the texture of the annulus, amount of bulge,
    presence of herniation, or presence of a hole in the annulus, and
    perform a discectomy.
  • More exposure is needed for significant spinal stenosis or central, lateral recess or foraminal stenosis.
  • When a total laminectomy is needed to
    expose the dura and nerve roots, remove the fascia entirely from the
    tip of the spinous process bilaterally. Extend the exposure laterally
    from the spinous process to the lamina with the Cobb elevators.
    Carefully protect the facet joint capsule. The exposure may be to the
    tips of the transverse processes if a fusion is to be done.
  • Note: The
    most important structure that must be exposed and clearly seen is the
    pars interarticularis. Identification of the pars is imperative to
    prevent its transection with subsequent spinal instability. By
    continually visualizing the pars, removal of the lamina can be done
    quickly and safely. The bone cutters remove the spinous process. I
    prefer to use the Midas Rex AM1 (Medix Rex Pneumatic Tools, Inc., Fort
    Worth, TX) to remove all of the lamina over the ligamentum flavum and
    down to a 1 mm thin shell over the dura. Alternatively, I use the Luxel
    rongeur by inserting it under the caudad edge of the cephalad lamina
    and rotate the instrument cephalad, rolling a bite of lamina off. This
    allows visualization under the instrument to see a possible inadvertent
    dura pinch early. Before using the Midas Rex tool, I expose the pars by
    curetting the caudal tip of the inferior facet. Seeing the articular
    surface of the superior facet and the pars at each level allows full
    removal of lamina and medial portion of the facet without danger of
    cutting the pars. Identify the pedicle as soon as possible to avoid
    removing too much facet.
  • To expose the lateral portion of the
    spinal canal, remember that the lateral wall may protrude significantly
    into the spinal canal. If the partial medial facetectomy is to be done,
    use the Midas Rex AM1 or AM3, the Kerrison rongeur, the Cloward chisel,
    or the Pheasant discotome. Starting medially on the lamina, cut the
    caudal portion of the lamina and continue laterally onto the inferior
    facet. The amount of inferior facet removed varies according to the
    pathology. If the chisel is used, insert it to remove the appropriate
    amount of the medial portion of the inferior facet and twist the
    chisel, removing the bone medially. This allows visualization of the
    facet join space and the superior facet. The shiny cartilaginous floor
    is the superior facet. The ligamentum flavum inserts on the superior
    facet. The nerve root may be under this superior facet.
  • The ligamentum should be opened at this
    point by one of numerous methods. Use the curet to detach the lateral
    ligamentum flavum from the edge of the superior facet. Position the
    Penfield 4 elevator, Penfield 3 elevator, or the cottonoid under the
    superior facet to protect the nerve. Use the Kerrison rongeur to remove
    the medial portion of the superior facet and the most lateral
    ligamentum flavum. The chisel is quite safe on the inferior facet
    because the superior facet provides a guard from possibly injuring the
    nerve root. With skill and experience, the superior facet likewise can
    be removed with a chisel by cutting over the pedicle with the Penfield
    elevator, protecting the nerve. With lateral recess stenosis, remove
    the medial facet to the parasagittal level of the medial wall of the
  • I prefer to use the Midas Rex bone cutter
    because it causes less splintering. Cut the lamina down centrally with
    the AM1. With the AM3, extend the bone removal laterally over the
    ligamentum flavum and foramen.
  • After the lamina is burred down to a thin
    layer over the dura and totally off the ligamentum flavum, open the
    ligament with a Penfield 3 elevator and clasp it with a ligamentum
    flavum clamp. Pass a cottonoid between the ligament and the dura.
    Remove the major portion of the ligament with a large, straight curet
    from the opposite side of the table. The most lateral ligament is
    removed by undercutting with the angled kerrison chisel from across the
    table. Position the cottonoid and have the assistant remove the
    ligamentum flavum with a 45° Kerrison rongeur from the other side of
    the table. Remove the medial edge of the superior facet with the
    lateral-most ligamentum flavum. The assistant on the opposite side of
    the table also can position this cottonoid very effectively using the
    sucker and the bayonet. Use the 90° Kerrison rongeur to remove this
    lateral portion of the ligamentum flavum.
  • The ligamentum flavum can be detached
    with a curet from its caudad and lateral attachments, and a curved
    osteotome can be used to free the cephalad attachment of the ligamentum
    flavum from the undersurface of the cephalad lamina. Use a nerve hook
    to pull the detached cephalad edge of the ligamentum flavum into the
    intralaminar area. Use a straight curet to detach the caudad edge of
    the ligamentum flavum from the edge of the caudad lamina and an angled
    curet to detach the lateral ligamentum flavum. With this detaching
    method, the ligamentum flavum can be retracted intact with a medial


    to the ligamentum flavum from the opposite side, allowing access to the
    spinal canal without excision of the ligamentum flavum. Although the
    ligamentum flavum, being elastic, will shrink from its original
    attachment, it will still provide an excellent dural covering when
    reapproximated on closing. There is some danger in detaching this
    ligamentum flavum in the lateral recess because of the nerve root. Be
    careful over the “critical angle,” which is the junction of the base of
    the superior facet and the caudad lamina, because the nerve root exits
    under this angle.

  • The key to a safe, effective foraminotomy
    is to expand the intervertebral foramen without damaging the pars
    interarticularis or the facet joint. A foraminotomy begins after
    removal of the lateral recess, identification of the pedicle, and
    identification of the pars interarticularis. The medial caudal aspect
    of the pedicle is the beginning of the intervertebral foramen. The pars
    forms part of the bony roof of the intervertebral foramen. The root
    exits around the pedicle, and it is the roof over that root as it exits
    that must be expanded first. I use the Midas Rex AM3 or M8 to an arc
    over the root, leaving a thin shell of bone over the root and plenty of
    the facet undersurface. Then insert the Kerrison rongeur on the root
    and remove the bone touching the nerve and any ligamentum flavum
    attached to it. Probe the foramen until it is clear. I use gallbladder
    probes up to 5 mm in diameter or a Woodson probe. Often, the tip of the
    superior facet compresses the nerve root from below. I routinely remove
    the cephalad tip of the superior facet with the Cloward chisel. The
    curved Kerrison rongeur removes more of the roof of the foramen
    laterally. Protect the pars. A portion of its undersurface can be
    carefully expanded to open the intervertebral foramen.
  • Uncinate ventral spurs may arise from the
    caudal vertebral body, caudal to the pedicle, at the edge of the disc
    space below; they are seen on CT foraminal reconstructions. The root
    can be tented over the spur and tethered laterally by foraminal
    ligaments. Removing the roof is not enough to relieve this nerve root
    tension. The spur under the root should be removed. Although these
    spurs can be removed from cephalad to caudad by putting a chisel under
    the root, they are more easily approached from the level below.
    Remember, these spurs are under the annulus of the disc below and
    covered with soft tissue, making removal with a chisel more difficult.
    Putting a knife under the nerve root is dangerous.
  • Expose the disc below. Working from
    caudad to cephalad, identify the exiting root. Open the disc with a
    knife laterally. Use the chisel and curet to burrow under the spur and
    then the endplate of the vertebra. Hollow out a space. Insert an angled
    curet between the root and the annulus-covered spur, and knock the spur
    into the hole. Leave it in the hole or remove it. It is safer to remove
    it after the root tension is relieved.
  • The foraminotomy can be performed from
    the “outside in.” Move to a paraspinous position through the same
    incision. Identify the superior facet and transverse processes above
    and below the pars. Several tacks can be taken from this point. One is
    to remove the intertransverse ligament, identify the nerve, and follow
    it back into the canal, removing any obstructions for a foraminotomy. I
    prefer to expose the caudal surface of the pedicle above, using the
    pars and transverse process as guides. Identify the nerve there and
    expand the intervertebral foramen. If there is a foraminal herniated
    nucleus pulposus, expose the cephalad surface of the pedicle below, and
    work cephalad to identify the disc, the nerve, and the herniation.
  • After the discectomy, the delicacy of the
    approach will determine how much fat is left covering the nerve root.
    Supplement this procedure with a free fat graft taken from the layer
    above the fascia in the caudal portion of the wound. When fat is not
    available, I use Depo-Medrol–soaked Gelfoam.
  • After closing any dead space left by the
    fat graft, close the fascia with interrupted 0 Vicryl. When midline
    fascial structures have been removed from the spinous process, reattach
    them. The layers above the fascia are closed with multiple layers of
    interrupted 2-0 Vicryl. Close the subcutaneous fat in at least two
    layers, tacking each layer to the lower layer. I usually drain both the
    subfascial and suprafascial layers. Close the subcutaneous layer
    immediately adjacent to the subcuticular layer. Close the skin with
    subcuticular sutures, benzoin, and Steristrips. Retract and cut off the
    sutures after the Steristrips are applied.
  • Position the patient on a standard operating frame.
  • Use skin-marking needles to identify the
    pedicles of the involved segment with a lateral radiograph. For L4–L5,
    align the needle markers over the pedicle at L-4 and the pedicle at
    L-5. Make the incision one fingerbreadth lateral to the spinous
    process, spanning between the pedicles of the involved segment (Fig. 138.29).
    Figure 138.29. Make the incision one fingerbreadth lateral to the spinous process, spanning between the pedicles of the involved segment.
  • Carry the incision through the skin and
    subcutaneous tissue. Open the fascia enough to admit an index finger
    that dissects down in a muscle-splitting dissection to the cephalad
    transverse processes. Use a Penfield 1 instrument or a small Cobb
    elevator to identify the transverse processes, but do not carry out
    vigorous muscle dissection at this point. Use your finger to palpate


    the cephalad-transverse process to the area of the pars
    interarticularis, just cephalad to the facet joint. Rest the Penfield 1
    on the more cephalad transverse process and position the McCulloch
    blade-spike retractor by placing the blade laterally against the soft
    tissue, then placing the spike medially just dorsal to the pars
    interarticularis. Do not hook it under the pars interarticularis.

  • By opening the retractor, visualize the
    transverse process. Obtain a lateral radiograph with a needle on the
    transverse process to confirm levels.
  • Use the Bovie and curet to dissect the soft tissue off the pars interarticularis and the base of the transverse process.
  • It is important to see the bone of the
    pars interarticularis. Too often, the dissection is carried out too far
    laterally. The transverse process is cleared off, but the actual
    location of the pedicle is more medial, and too much time is wasted in
    a more lateral position. Identify the pars and follow the bone of the
    transverse process back to the dorsal surface of the pedicle. At this
    point, there are times when a portion of the cephalad facet joint, or
    cephalad lateral portion of the inferior facet, has to be removed with
    Kerrison rongeur to provide proper exposure of the intertransverse
    area. For better exposure, laterally retract the muscle off the
    intertransverse ligament and hold it with the lateral blade retractor (Fig. 138.30).
    Figure 138.30.
    For better exposure of the intertransverse area, laterally retract the
    muscle of the intertransverse ligament. (Note: The illustration depicts
    a larger field of visualization than actually performed.) After opening
    the fascia, use finger dissection to clear the transverse process.
    Insert the retractor.
  • Using a straight and an angled curet,
    detach the intertransverse ligament from the cephalad-transverse
    process, the dorsal surface of the pedicle, and the lateral surface of
    the pars interarticularis. Identify this ligament, hook it with a blunt
    nerve hook, pull it laterally, and free it up with the small Kerrison
    rongeur under direct visualization.
  • Caution: Sometimes, distinguishing the ligament from the nerve is not easy. Proceed carefully.
  • Identify the nerve as it exits around and just caudal to the cephalad pedicle (Fig. 138.31).
    Figure 138.31.
    Identify the cephalad transverse process, then expose the part
    interarticularis medially. Detach the intertransverse ligament.
    Identify the pedicle, then the nerve exiting just caudal to the
    pedicle. The disc is caudal to the nerve.
  • Use the Penfield 4 elevator to palpate
    gently cephalad to the nerve, starting at the medial wall of the
    pedicle and progressing laterally. Beware of bleeding in this area.
  • Identify the caudal aspect of the nerve and use the microsucker retractor to retract the nerve cephalad. Using


    the Penfield 4 elevator, identify the disc caudal to the nerve. Be
    aware that the dorsal ganglion of the nerve may feel like a disc
    fragment under the nerve. Carefully identify the nerve and the disc (Fig. 138.31). Follow the nerve laterally to insure removal of any lateral disc fragments.

  • Remember:
    • Identify the cephalad transverse process.
    • Identify the pars interarticularis to stay medially.
    • The pedicle is the key landmark.
    • Laterally retract the intertransverse ligament.
Each reference is categorized according to the following
scheme: *, classic article; #, review article; !, basic research
article; and +, clinical results/outcome study.
+ 1. Apuzzo MJ, Weiss MH, Hyden JS. Transoral Exposure of the Atlanto-Axial Joint. J Neurosurg 1978;3:201.
+ 2. Bailey RW, Bagley CD. Stabilization of the Cervical Spine by Anterior Fusion. J Bone Joint Surg Am 1960;42:565.
+ 3. Cloward R. Ruptured Cervical Intervertebral Discs. Codman Signature Series 4. Codman and Shurtleff, 1974.
+ 4. Duncan HMM, Jonck LM. The Presacral Plexus in Anterior Lumbar Fusion of the Lumbar Spine. S Afr J Surg 1965;3:93.
+ 5. Dwyer AF. Experience of Anterior Correction of Scoliosis. Clin Orthop 1973;93:192.
+ 6. Dwyer AF, Newton NC, Sherwood AA. An Anterior Approach to Scoliosis. Clin Orthop 1969;62:192.
+ 7. Fang HSY, Ong BG. Direct Anterior Approach to the Upper Cervical Spine. J Bone Joint Surg 1962;44-A:1588.
+ 8. Flynn JC, Hoque A. Anterior Fusion of the Lumbar Spine. J Bone Joint Surg 1979;61-A:1143.
+ 9. Freebody D, Bedall R, Taylor RD. Anterior Transperitoneal Lumbar Fusion. J Bone Joint Surg 1971;53-B:617.
# 10. Goss CM, ed. Gray’s Anatomy of the Human Body, 29th ed. Philadelphia: Lea & Febiger, 1973.
+ 11. Harmon PH. Anterior Extraperitoneal Lumbar Disc Excision and Vertebral Bone Fusion. Clin Orthop 1963;16:169.
# 12. Henry AK. Extensive Exposure. Baltimore, Williams & Wilkins, 1959.
# 13. Hodgson AR, Rau ACM. Anterior Surgical Approaches to the Spinal Column. In: Apley AG, ed. Recent Advances in Orthopedics. Baltimore, Williams & Wilkins, 1964:326.
+ 14. Hodgson AR, Rau ACM. Anterior Approach to the Spinal Column. Recent Advances in Orthopaedics IX 1969;9:289.
+ 15. Johnson RM, McGuire EJ. Urogenital Complications of Anterior Approaches to the Lumbar Spine. Clin Orthop 1981;154:114.
+ 16. LaBate JS. The Surgical Anatomy of the Superior Hypogastric Plexus-Presacral Nerve. Surg Gynecol Obstet 1938;67:199.
# 17. Logue V. Compressive Lesions at the Foramen Magnum. In: Ruge D, Wiltse L, eds. Spinal Disorders: Diagnosis and Treatment. Philadelphia, Lea & Febiger, 1977:249.
+ 18. Nanson EM. The Anterior Approach to Upper Dorsal Sympathectomy. Surg Gynecol Obstet 1957;104:118.
# 19. Perry J. Surgical Approaches to the Spine. In: Pierce D, Nichols V, eds. The Total Care of Spinal Cord Injuries. Boston: Little, Brown & Co., 1977:53.
+ 20. Riceborough EJ. The Anterior Approach to the Spine for Correction of the Axial Skeleton. Clin Orthop 1973;93:207.
+ 21. Riley L. Surgical Approaches to the Cervical Spine. Clin Orthop 1973;91:16.


+ 22. Riley L. Surgical Approaches to the Anterior Structures of the Cervical Spine. Clin Orthop 1973;91:10.
# 23. Robinson RA. The Craft of Surgery, 2nd ed. Boston: Little, Brown & Co., 1971.
# 24. Robinson RA. Approaches to the Cervical Spine C1-T1. In: Schmidek HH, Sweet WH, eds. Current Techniques in Operative Neurosurgery. New York: Grune & Stratton, 1978.
# 25. Robinson RA, Southwick WO. Surgical Approaches to the Cervical Spine. Instr Course Lect 1960;17:299.
# 26. Rothman R. The Spine, Vol I. Philadelphia: W.B. Saunders, 1975.
+ 27. Royal ND. A New Operative Procedure in the Treatment of Spastic Paralysis and Its Experimental Basis. Med J Anat 1924;77:30.
+ 28. Scott R. Innervation of the Diaphragm and Its Practical Aspects in Surgery. Thorax 1965;20:357.
# 29. Watkins RG, O’Brien JP. Anatomy of the Cervical Spine (Sound/Slide Program). Atlanta, American Academy of Orthopaedic Surgeons, 1980.

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More