Thoracic and Lumbar Trauma

By admin On Apr 5, 2024

Ovid: Spine

Editors: Bono, Christopher M.; Garfin, Steven R.

Title: Spine, 1st Edition

> Table of Contents > Section II – Trauma > 5 – Thoracic and Lumbar Trauma

Thoracic and Lumbar Trauma

Kern Singh

Alexander R. Vaccaro

The thoracolumbar spine is the most common site of
spinal injuries. Most of these injuries occur in males (15 to 29 years
old) usually as the result of significant force impact, such as motor
vehicle accidents. Most injuries (52%) occur between T11 and L1,
followed by L1-5 (32%) and T1-10 (16%). Depending on the type of
fracture, associated injuries occur in 50% of patients mainly as a
result of a distraction force. Associated injuries include
intraabdominal bleeding from liver and splenic injuries, vessel
disruption, and pulmonary injuries (20% of patients). Contiguous and
noncontiguous spine injuries are present in 6% to 15% of patients.

THORACOLUMBAR ANATOMY

The thoracic spinal cord is protected from injury by the
surrounding paraspinal musculature, the vertebral elements, and the
thoracic rib cage. The sternum and the rib cage significantly limit
motion in the thoracic spine. As a result of the significant amount of
force necessary to disrupt the protective enclosure of the thoracic
spinal cord, spinal injuries in this region are associated with a high
incidence of neurologic injury. This high incidence also is a function
of the decreased spinal canal diameter to spinal cord diameter ratio,
particularly between T2 and T10. High-energy injuries in this area
usually result in a 6:1 ratio of complete to incomplete neural
deficits. The physiologic kyphosis of the thoracic spine may predispose
it to flexion/axial load injuries.

The thoracolumbar junction is a transitional region
between the less mobile thoracic spine and the more flexible lumbar
spine. In this junctional region, the rib cage no longer provides
protection and support to the vertebral column. Also, the thoracic
vertebral bodies are not as large as the lumbar vertebral bodies; they
are less able to resist deformity after specific load applications.
These factors render the thoracolumbar junction more vulnerable to
injury and make it the most common location for burst-type fractures.

INITIAL TREATMENT AND EXAMINATION

Initial evaluation should begin with the ABCs (airway,
breathing, circulation) of trauma care. A cervical collar should be
placed and any extremity injuries splinted when the airway is secured.
The patient now can be logrolled carefully, and the spine can be
palpated for tenderness, step-offs, swelling, or visual deformities. Of
patients with persistent localized tenderness after trauma to the
thoracolumbar spine and absence of an obvious radiographic deformity,
30% may have an occult spinal fracture.

The detailed neurologic exam should include motor
testing, dermatomal sensory testing, lumbar and sacral root motor
evaluation, and examination of reflexes. Spinal shock
refers to flaccid paralysis due to a physiologic disruption of all
spinal cord function. The presence of the bulbocavernosus reflex
heralds the end of spinal shock and allows for an accurate assessment
of the patient’s neurologic status typically 48 hours after the injury.
The bulbocavernosus reflex is tested by squeezing the glans penis or
clitoris and observing for reflex anal sphincter contracture. It also
may be tested by tugging on an indwelling catheter and observing for an
“anal wink.”

A complete neurologic injury
is marked by a total absence of sensory and motor function below the
anatomic level of injury in the absence of spinal shock. In an incomplete
lesion, residual spinal cord or nerve root function exists below the
anatomic level of injury. An incomplete spinal cord lesion may manifest
as one of four syndromes (Table 5-1).

Hypotension secondary to neurogenic or hemorrhagic shock
must be reversed through fluid or blood replacement, with or without
the use of vasopressors. Intravenous methylprednisolone is administered
routinely within 8 hours of a spinal cord injury in the absence of
specific contraindications (Table 5-2).

Deep venous thrombosis prophylaxis is paramount. The use
of intermittent external pneumatic compression devices, static
compression stockings, and, in select patients, subcutaneous (5000 U
subcutaneously every 12 hours) or intravenous low-molecular-weight
heparin helps to minimize potentially fatal pulmonary emboli.

RADIOLOGIC EVALUATION

The radiographic evaluation begins with plain radiographs of the entire spine (anteroposterior and lateral views). The

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posterior vertebral body line should be assessed on the lateral
radiograph. Disruption of this line may signal spinal canal compromise
from a burst-type fracture. Other radiologic signs suggesting a
compression spinal injury include buckling of the cortical margins,
loss of vertebral body height, and an intravertebral vacuum sign. If
the cervicothoracic junction (C7-T1) is difficult to visualize, a
swimmer’s view (lateral view with a maximally abducted arm) or an
oblique view may help define the vertebral anatomy.

TABLE 5-1 SPINAL CORD INJURY SYNDROMES

Syndrome	Characteristics	Prognosis
Central	Most common. UE > LE. Motor and sensory loss	Fair
Anterior	Loss of motor function with possible sparing of proprioception and pressure sensation	Poor
Posterior	Very rare. Loss of proprioception and pressure sensation. No motor loss	Good
Brown-Séquard	Ipsilateral motor loss and contralateral pain and temperature loss	Best
LE, lower extremity; UE, upper extremity.

Vertebral alignment also should be assessed on the
anteroposterior view. Vertebral body cortical disruption may suggest a
lateral compression fracture. The spinous processes should be in the
midline with a relatively consistent interpedicular distance.
Displacement (i.e., spreading) may represent significant posterior
element injury and spinal instability.

Further clarification of the degree of tissue disruption
may require the use of computed tomography (CT) or magnetic resonance
imaging (MRI). CT is useful in evaluating the integrity of the middle
(posterior vertebral body) and posterior (posterior elements) columns
of the vertebral body. On plain radiographs, approximately 25% of burst
fractures may be misdiagnosed as stable compression fractures owing to
lack of clear visualization of the vertebral bony anatomy. The greatest
disadvantage of CT is its limited sensitivity in showing consistently
specific soft tissue injuries (disc herniation, epidural hematoma,
ligamentous disruption, or spinal cord injury) (Table 5-3).

TABLE 5-2 METHYLPREDNISOLONE DOSING

Time from Injury (h)	Dose of Methylprednisolone (mg/kg/h)	Duration (h)
< 3	5.4	24
3-8	5.4	48
> 8	No treatment	No treatment

MRI is useful when visualization of the nonbone
structures of the spine is necessary. MRI is the definitive diagnostic
modality in the evaluation of spinal cord injury. It is extremely
useful in all cases with neurologic deficit to assess for intrinsic and
extrinsic spinal cord pathology. MRI can help illustrate and elucidate
the various spinal cord parenchymal findings, such as edema, hematoma,
and physical transection of the neural elements.

Edema is seen as a fusiform enlargement of the spinal
cord with increased signal intensity on T2-weighted images. Hematoma is
characterized by decreased signal intensity on T2-weighted images
acutely and often is surrounded by a halo of T2-weighted enhancement
from adjacent edema. Edema extending more than two vertebral levels and
the presence of hematoma within the spinal cord are considered poor
prognostic signs for potential functional motor recovery.

MRI also can help define acute ligamentous disruption. A
“black stripe sign” may indicate disruption of the posterior
longitudinal ligament or supraspinous ligament. A bright signal within
the substance of the interspinous space reliably represents ligamentous
injury. MRI is helpful in the evaluation of acute traumatic disc
disruptions, especially in the setting of a facet dislocation. MRI also
may be useful in the postinjury period in cases of late development or
worsening of a preexisting neurologic injury. In these situations, a
treatable posttraumatic cyst or syrinx often can be diagnosed.

CLASSIFICATION SCHEMES

The three-column theory of spinal instability by Denis
is used commonly to define vertebral column injuries. The anatomic
spine in this system is divided into three columns. Denis divided
thoracic and lumbar spinal injuries into minor and major injuries.
Fractures of the spinous and transverse processes, the pars
interarticularis, and the facet articulations were categorized as minor
injuries. Major spinal injuries were divided into compression
fractures, burst fractures, flexion/distraction injuries, and
fracture-dislocations (Figs. 5-1, 5-2, 5-3 and 5-4).

McAfee et al described a CT-based classification system.
Their system included six fracture types based on the failure mode of
the middle column: wedge-compression, stable burst, unstable burst,
Chance, flexion/distraction, and translational fractures (Table 5-4).

Ferguson and Allen presented a mechanistic
classification of thoracolumbar injuries. They described seven injury
patterns: compressive-flexion, distractive-flexion, lateralflexion,
translational, vertical-compression, and distractive-extension
injuries. This system categorizes injuries by the forces that create
them and is useful in guiding nonoperative and operative treatment
strategies (Table 5-5).

SURGICAL DECISION MAKING

Surgical management of thoracolumbar injuries attempts
to shorten hospitalization; maximize function; facilitate nursing care;
and prevent deformity, instability, or pain. White and Panjabi defined
clinical instability as the “loss of the ability of the spine under
physiologic loads to maintain relationships between vertebrae in such a
way that there is neither damage nor subsequent irritation to the
spinal cord or nerve roots, and in addition, there is no development of
incapacitating deformity or pain.”

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TABLE 5-3 DIAGNOSTIC IMAGING MODALITIES

Imaging Modality	Advantages	Disadvantages
Plain radiograph	Inexpensive, quick	Poor visualization of cervicothoracic junction and middle spinal column
CT	Excellent visualization of bony anatomy, particularly middle spinal column and cervicothoracic junction. Assesses spinal canal patency	Poor visualization of soft tissues
MRI	Excellent visualization of soft tissues, including ligaments, disc, and spinal cord	Poor visualization of detailed bony anatomy
CT, computed tomography; MRI, magnetic resonance imaging.

Figure 5-1 Denis’s classification of thoracolumbar compression injuries. These fractures may involve both end plates, type A (A); the superior end plate only, type B (B); the inferior end plate only, type C (C); or a buckling of the anterior cortex with both end plates intact, type D (D).

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Figure 5-2 Denis’s classification of thoracolumbar burst fractures. Types A, B, and C represent fractures of both end plates (A), the superior end plate (B), and the inferior end plate (C). Type D fracture is a combination of a type A burst fracture with rotation (D),
which is best appreciated on an anteroposterior radiograph. The
superior or inferior end plate, or both, may be involved with this
fracture. Type E fractures are burst fractures with lateral translation
or flexion (E).

Surgical intervention often is determined by the
assessment of the integrity of the posterior osteoligamentous complex.
In a typical burst fracture, if there is marked widening of the
posterior spinous processes with an obvious kyphotic malalignment, this
would be considered an unstable fracture with the potential for
deformity progression. Denis defined instability
as a disruption of two or more of the three spinal columns and
categorized instability into three groups: mechanical, neurologic, and
combined. Mechanical instability included multiple column injuries in
which the posterior elements were disrupted in distraction, and late
kyphosis was a potential. Neurologic instability described a neurologic
deficit in the setting of a spinal fracture. Combined instability
described an unstable mechanical fracture in the setting of a
neurologic deficit.

The optimal timing for medical or surgical intervention
(decompression and stabilization) is unclear. A critical window of
opportunity (possibly <3 hours) may exist in which the decompression
of extrinsic pressure on the spinal cord and spinal stabilization may
enhance functional neurologic outcome. Vaccaro et al
reported the only controlled, prospective, randomized study on the
timing of surgical intervention in cervical spinal cord injury. The
authors found no significant difference in functional neural recovery
when patients were operated on either early (<3 days) or late (>5
days). Progressive neurologic loss associated with an unstable fracture
pattern with significant spinal cord compression is an indication for
emergent surgical intervention.

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Figure 5-3 Denis’s classification of flexion/distraction injuries. These may occur at one level through the bone (A), at one level through the ligaments and disc (B), at two levels with the middle column injured through the bone (C), or at two levels with the middle column injured through the ligament and disc (D).

SURGICAL SPINAL DECOMPRESSION

The role of surgical decompression of thoracolumbar
spinal injuries with symptomatic neural compression is unclear. Despite
varied opinions, there is no direct correlation between the percentage
of canal occlusion shown radiographically and the severity of
neurologic deficit after burst fractures. Instead the initial force
imparted to the spinal cord or the cauda equina, along with the
associated hematoma, edema, and vascular ischemia perpetuated by
various neurotrophic and vasoactive agents may be the underlying cause
of neurologic injury.

Approximately 60% of patients with neurologic injury
below T12 gain some return of neurologic function with nonoperative
treatment. Neurologic recovery is more predictable, however, following
an anterior decompression in spinal cord compression. Late
decompression, even several years after injury, may enhance neurologic
recovery of the spinal cord, conus medullaris, and cauda equina.

The posterior approach is an indirect method of
relieving canal compression via ligamentotaxis. This method is
accomplished more efficiently if performed in the early peritrauma
period. Several studies have shown that the spinal canal remodels or
enlarges with time in nonoperatively treated and operatively treated
fractures in a predictable fashion

The spinal level, degree and nature of canal compromise,
and experience of the surgeon dictate the choice of surgical approach.
Multiple variations on the approach to the thoracolumbar spine exist
based on three methods to decompress the thecal sac: anterior,
posterior, and posterolateral (Table 5-6).

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Figure 5-4 Denis’s classification of fracture-dislocations. These injuries may occur at one level through the bone (A), at one level through the ligaments and disc (B), or at two levels with the middle column injured through the ligament and disc (C).

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TABLE 5-4 THE McAFEE CLASSIFICATION SYSTEM

Type of Fracture				Mechanism
Columns	Anterior	Middle	Posterior
Wedge compression	Compression	None	None	Forward flexion
Stable burst	Compression	Compression	None	Compressive load
Unstable burst	Compression	Compression	Compression, lateral flexion, rotation	Compression, lateral flexion, rotation
Chance	Tension	Tension	Tension	Horizontal avulsion
Flexion distraction	Compression	Tension	Tension	Flexion distraction
Translational	Shear	Shear	Shear	Shear

TABLE 5-5 THE FERGUSON AND ALLEN CLASSIFICATION SYSTEM FOR SPINAL FRACTURES

Type of Fracture
Columns		Anterior	Middle	Posterior
Compressive flexion
	Type I	Compression	None	None
	Type II	Compression	None	Tension
	Type III	Compression	“Blown out”^*	Tension
Distractive flexion		Tension	Tension	Tension
Lateral flexion
	Type I	Unilateral compression	Unilateral compression	None
	Type II	Unilateral compression	Unilateral compression	Ipsilateral compression/contralateral tension
Translational		Shear	Shear	Shear
Torsional flexion		Compression/rotation	Disrupted	Tension/rotation
Vertical compression		Compression	Bony compression	Bony involvement
Distractive extension		Tension		Compression
^*“Blown out”—evidence of middle column bone rotated into the neural canal between pedicles.

TABLE 5-6 SURGICAL APPROACHES TO SPINAL DECOMPRESSION

Approach	Advantages	Comments
Anterior	Easier access to retropulsed vertebral bone and discal material	Anterolateral approach—transthoracic T4-9, thoracoabdominal T10-L1, retroperitoneal T12-L5
	Direct visualization of compressed neural tissue	Right-sided approach—above T10 to avoid great vessels
	Minimal manipulation of spinal cord	Right-sided approach—above T10 to avoid great vessels
Posterior	Effective when using distractive instrumentation to reduce retropulsed bone fragments	Posterior indirect reduction via ligamentotaxis is more efficient if done within 2-3 days of injury
Posterolateral	Instrumentation can be performed without the need for a second anterior staged procedure	One is able to access the thecal sac via the pedicle
		Difficult anterior column reconstruction
	Advantageous in lower lumbar fractures and lateralized nerve root entrapment	Increased risk of neural injury secondary to neural manipulation

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SPINAL INSTRUMENTATION

Since the introduction of Harrington rod internal
fixation, there has been progressive development of various spinal
fixation systems based on segmental fixation of the spine. The choice
of spinal implant is determined by the nature, degree, or biomechanics
of the existing instability; the quality (bone density) of the spinal
elements; and the medical condition of the patient.

Anterior Instrumentation

Approximately 80% of the axial load transmitted through
the spine is through the intact anterior column. Direct restoration of
the load-bearing function of the anterior spine is paramount in
addressing spinal instability secondary to thoracolumbar trauma.
Indications for anterior spinal surgery in patients with thoracolumbar
injuries include unstable fractures requiring anterior column support,
bony or discal compression of the thecal sac in the setting of a
neurologic injury best addressed anteriorly, and unstable fractures
(select burst injuries) that require stabilization best achieved
through an anterior approach to preserve spinal motion segments (Fig. 5-5).

Interbody spacers inserted in an intracolumnar position
act as a load-sharing device restoring axial stability until
arthrodesis is obtained. With a deficient anterior column and no
structural interbody spacer, a posterior spinal construct bears most of
the axially applied loads leading to the potential for nonunion and
instrument failure.

Figure 5-5
Postoperative radiograph after completion of an anterior thoracolumbar
decompression and stabilization procedure using autologous iliac crest
bone graft and an anterior thoracolumbar plate and screws.

The most commonly used interbody spacer is an autologous
tricortical iliac crest, although allograft sources, such as a tibial
or femoral shaft or metallic mesh cages, are gaining popularity. Iliac
crest interbody grafts allow for a faster rate of bony incorporation
owing to their biocompatibility than do allograft strut grafts.
Allograft strut grafts are able to withstand greater physiologic loads,
however, in the erect spine in the early reconstruction and healing
period. Several authors have reported successful results using anterior
cortical allograft strut grafts in thoracolumbar fractures with fusion
rates approaching greater than 90% at greater than 5-year follow-up
with minimal graft subsidence and change in sagittal alignment.

A functional posterior osteoligamentous complex is
crucial to the success of an anterior spinal construct. In the presence
of posterior ligamentous injury, an anterior stand-alone procedure
using a structural interbody graft followed by adjunctive internal
fixation (i.e., a dual rod or plating fixation device) may be adequate
in restoring enough stability until bone healing occurs. If significant
posterior instability still exists, however, a staged posterior
stabilization procedure should be done.

Anterior thoracolumbar decompression procedures followed
by reconstruction are technically demanding procedures not without
significant potential complications. Vascular complication rates of
5.8% have been reported, accompanied by a 2.4% rate of deep venous
thrombosis and a 10% rate of dural laceration.

Posterior Instrumentation

Posterior spinal approaches allow for efficient
realignment of the spine, direct and indirect decompression of the
neural elements, and protection against late deformity and instability
through the application of spinal instrumentation and subsequent
fusion. Posterior spinal instrumentation allows for application of
specific vector forces to the spine to correct or improve spinal
alignment. The most commonly applied vector forces are cantilever
bending and distraction. With a prudent distraction force, restoration
of vertebral body height and partial clearance of bone or discal
fragments from within the spinal canal by ligamentotaxis can be
achieved. Spinal canal clearance through ligamentotaxis optimally is
achieved within the first 2 to 3 days after injury. Posterior
distraction techniques may enlarge the compromised canal 40% to 75%.

Biomechanically, a longer applied longitudinal component
(rod) reduces the risk of terminal implant cutout or dislodgment by
increasing the distance from the fracture site, decreasing the forces
on the hook. Especially with hook-based systems, this often requires
the immobilization of five or six motion segments that may contribute
to increased global spinal stiffness and subsequent junctional
degeneration. Historically, in an attempt to preserve the motion of
uninjured motion segments, the “rod long-fuse short” technique was
introduced. With this method, only one level above and one level below
the fracture were fused, and three levels above and below the injury
were spanned by instrumentation, which was removed at 1 year after
surgery. This technique eventually lost popularity as gross and
histologic findings of osteoarthritis were noted along the unfused

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but instrumented spinal segments at the time of implant removal.

Shortcomings of distraction rod-hook techniques for
fracture reduction and stabilization include hook dislodgment, late
vertebral collapse, and progressive kyphosis after rod removal.
Overdistraction with long rods may lead to iatrogenic loss of lumbar
lordosis and the development of a painful flat back deformity. Various
modifications of hook-rod constructs were initiated to address these
issues. More square hooks, which prevented rod rotation, allowed for
gentle contouring of the rod and as such decreased hook cutout. Edward
sleeves, made of high-density polyethylene, which were placed along the
rod, were developed to provide an anterior vector moment to the spine
through three-point or four-point bending strategies.

The development of pedicle screw anchors provided an
additional method of stabilizing an unstable three-column spinal injury
through three-column bone fixation. Pedicle screw implants potentially,
in nonosteoporotic patients, allow for shorter posterior fixation
lengths, while conferring adequate spinal stability. Experimental data
confirmed that short-segment pedicle screw constructs provide
torsional, flexural, and compressive rigidity comparable to longer
hook-rod constructs. Despite the increased rigidity of pedicle screw
systems, posterior short-segment fixation of unstable thoracolumbar
fractures has resulted in high failure rates.

The best candidates for posterior short-segment pedicle
screw fixation (one level above and one level below the fracture level)
seem to be patients with flexion/distraction injuries or lower lumbar
burst fractures in which the weight-bearing line is posterior to the
posterior vertebral body wall. Transpedicular intracorporeal grafting
combined with short-segment instrumentation has been offered as an
alternative to a staged anterior column reconstruction procedure. This
technique has not been shown to decrease the incidence of loss of
sagittal plane alignment or instrumentation failure, however, compared
with nonintracorporeal grafted cases at long-term follow-up.

FRACTURE SUBTYPES

Spinal injuries can be divided into several categories
based on their biomechanical and anatomic characteristics and the
patient’s neurologic status (Table 5-7).

Minor Injuries

Transverse process, spinous process, and articular
process fractures resulting from direct trauma or severe muscular
contractions may be treated symptomatically with or without a brace for
comfort. The importance of assessing for spinal stability after an
initial immobilization period, if deemed necessary, with
flexion/extension plain radiographs cannot be overemphasized. Care must
be taken to avoid undertreatment and missing a potentially unstable
spinal injury. An acute isolated fracture of the pars interarticularis
should be immobilized in a well-molded total contact thoracolumbosacral
orthosis. If the fracture is below L3, a unilateral thigh extension
usually is recommended.

Compression Fractures

Surgical stabilization may be indicated in compression
(wedge) fractures if there is greater than 20 to 30 degrees of initial
kyphosis (significant posterior osteoligamentous disruption) and
greater than 50% loss of anterior vertebral body height (Fig. 5-6).
Ferguson-Allen type I compressive flexion injuries typically can be
treated with an extension cast or orthosis and early ambulation. If the
fracture is proximal to T7, a cervical extension to the brace or cast
is recommended. Type II and type III compressive flexion injuries
without a neurologic deficit generally are stabilized with posterior
nonsegmental or segmental instrumentation. Ferguson-Allen type II
compressive flexion injuries at the thoracolumbar junction often are
treated with posterior compression instrumentation, with the intact
middle column being used as a hinge to restore lordosis. Type III
injuries (which are burst fractures) without significant canal
compromise and evidence of significant posterior osteoligamentous
disruption (i.e., kyphosis >20 to 30 degrees or anterior loss of
vertebral body height >50% or both) may be treated with the use of
distraction-lordosis instrumentation to restore anterior and middle
column height. Care must be taken to avoid overdistraction in patients
with posterior column. A tension force placed on the neural elements
from overdistraction can result in significant neurologic injury. Often
a posterior interspinous wire is placed at the level of the posterior
ligamentous injury, preventing overdistraction, while accomplishing
fracture realignment through subsequent spinal distraction. If
short-segment fixation strategies are chosen, strict postoperative
immobilization in a custom-molded hyperextension orthosis or body cast
for a minimum of 3 months is recommended to decrease the potential for
spinal deformity recurrence and internal fixation failure.

Many surgeons continue to use the time-honored procedure
of segmental fixation using sublaminar wires (Luque rods [rectangle]
and sublaminar wires). This procedure rarely is performed in the
setting of an intact or incomplete neurologic examination. If this
technique is chosen, the Luque rectangle is prebent in mild
hyphokyphosis to reduce the segmental kyphosis at the level of injury.
This technique generally incorporates three levels above and two to
three levels below the level of injury.

More recently, the use of percutaneous cement
augmentation in symptomatic osteoporotic compression fractures has been
reported (vertebroplasty or kyphoplasty, which uses balloon elevation
of the vertebral end plates before cement insertion). Currently the
indications of these techniques for traumatic fractures of the thoracic
and lumbar spine are unclear.

Burst Fractures

Nonoperative treatment of burst fractures usually
involves a period of bed rest until resolution of initial symptoms,
followed by progressive ambulation in a full contact orthosis or cast
for 12 to 24 weeks with or without a unilateral thigh extension for the
initial 6 weeks of treatment. Several studies have evaluated back pain
associated with burst fractures and nonoperative management. Most
studies have concluded

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that
the back pain is due to progressive degenerative changes as a result of
the initial injury. Residual symptomatic foraminal stenosis, segmental
instability, or sagittal plane deformity is a rare late manifestation
of a healed thoracolumbar burst fracture.

TABLE 5-7 MANAGEMENT OF THORACOLUMBAR FRACTURES

Type	Nonsurgical Management	Surgical Indications	Comments
Minor injuries	TLSO—fracture below L3 add unilateral thigh extension	Instability on flexion/extension plain x-rays	Minor injuries are transverse/spinous/articular process fractures
Compression fractures	Extension TLSO cast or orthosis Early ambulation If fracture proximal to T7, add a cervical extension to the brace or cast	>20-30 degrees of initial kyphosis (significant posterior osteoligamentous disruption) > 50% loss of anterior vertebral body height	Use nonsegmental hook-rod construct to apply distraction-lordosis force vectors for reduction Short-segment pedicle screw construct may be used if followed by immobilization in a custom-molded hyperextension orthosis or body cast for a minimum of 3 m
Burst fracture	Bed rest until resolution of constitutional symptoms Progressive ambulation in a full-contact orthosis or cast for 12-24 wk with or without a unilateral thigh extension (fracture L3 or lower) for the initial 6 wk of treatment	Neurologically intact Kyphosis >20 degrees Facet subluxation or spreading of the interspinous process distance >50% loss of anterior vertebral body height Neurologically compromised Surgical decompression with imaging documentation of significant neural compression	No definitive evidence that correlates the degree of neural impingement with the severity of neurologic deficit after thoracolumbar trauma Anterior approach affords best canal decompression, should be followed by anterior column reconstruction ± anterior and/or posterior instrumentation
Distraction/flexion Injury	Rarely indicated in an adult patient owing to the unpredictable nature of healing of this injury subtype	A compression force vector is used to reduce the injury deformity. Care should be taken not to cause iatrogenic retropulsion of bone or discal material into the canal	ALL serves as a tension band with this injury Look for associated intraabdominal viscous injury with this injury mechanism
Fracture-dislocations	Rarely indicated owing to the significant degree of instability and deformity associated with this injury subtype	Posterior facet fracture-dislocation, rotational instability or a translational shear injury in the absence of a neurologic deficit requires an initial posterior segmental reduction and stabilization procedure before considering the need for an anterior decompressive and stabilization procedure	Awake intubation may minimize neurologic injury associated with positioning
Distraction/extension injury	Consider an attempt to reproduce the preinjury sagittal profile of the patient regardless of neurologic status through bedding supplements or skeletal traction	Surgical stabilization with segmental internal fixation initially via a posterior approach Consider a staged anterior stabilization procedure if a significant anterior column defect is present	High association with metabolic bone disease and a preexisting spinal deformity, e.g., ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis
ALL, anterior longitudinal ligament; TLSO, thoracolumbosacral orthosis.

In a neurologically intact patient with significant
disruption of the posterior osteoligamentous complex (i.e., initial
kyphosis >20 degrees), the presence of facet subluxation or
spreading of the interspinous process distance, or greater than 50%
loss of anterior vertebral body height, surgical stabilization may help
to restore and maintain adequate spinal alignment. Surgical
intervention also is performed in an acute burst fracture with imaging
documentation of significant neural compression in the setting of an
incomplete neurologic deficit. Neurologic improvement has been seen 2
years after an injury following a late decompression (Fig. 5-7)

From the literature, no conclusive evidence supports a
direct relationship between preinjury canal size and the force imparted
to the spine at the time of trauma and a

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patient’s
resulting neurologic status. The degree of canal diameter and area is
significantly more compromised at the time of trauma than that noted on
postinjury MRI or CT evaluation.

Figure 5-6
Segmental pedicle screw construct used to treat a compression fracture
that involved loss of greater than 50% of anterior vertebral height and
disruption of the posterior interspinous ligaments.

Distraction/Flexion Injuries

Distraction/flexion injuries with disruption of the
interspinous ligaments and posterior longitudinal ligament (and
possibly disc space) heal slowly and unpredictably and often benefit
from surgical stabilization. Most posterior spinal implant techniques
immobilize the vertebral level above and below the injury or at the
vertebral level of injury and the level below if the injury is located
anatomically below the pedicle of the cephalad vertebrae. Caution in
the use of this reduction maneuver must be exercised if the middle
column is comminuted for the fear of retropulsion of bone or disc
material into the spinal canal or if the posterior facets are
incompetent, which may prevent a controlled anatomic reduction. If the
axis of rotation is posterior to the anterior spinal column and
anterior column compression failure is present, a distraction maneuver
may be applied at levels above and below the injury level when the
posterior elements at the fracture site are stabilized to prevent
posterior element distraction. The anterior longitudinal ligament in
this case serves as a stabilizing tension band.

Fracture-Dislocations

Any evidence of posterior facet fracture-dislocation,
rotational instability, or a translational shear injury in the absence
of a neurologic deficit requires an initial posterior segmental
reduction and stabilization procedure before considering the need for
an anterior decompressive and stabilization procedure. When reduction
is complete, a neutralization spinal implant strategy may be employed
to confer optimal stability and to prevent future fracture displacement
(Fig. 5-8). An awake intubation followed by
awake patient positioning is helpful in the absence of a complete
spinal cord injury to help protect the neural elements from further
injury due to voluntary patient splinting and afford real-time
surveillance of the neurologic exam.

Figure 5-7 (A)
Sagittal MRI of a 34-year-old man who sustained a burst fracture to the
T12 vertebral body. Note the retropulsion of the posterior vertebral
body with compression of the anterior thecal sac. (B) Axial CT scan of the T12 burst fracture shows middle column failure with approximately 25% to 30% canal occlusion.

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Figure 5-8 (A)
Sagittal CT reconstruction of a fracture-dislocation of the
thoracolumbar spine shows marked vertebral body displacement and canal
narrowing. (B) Sagittal MRI of the injury
shows marked canal narrowing. Note the draping of the spinal cord over
the posterosuperior edge of the caudal thoracic vertebrae. (C)
Postoperative lateral radiograph shows reduction of the spinal
deformity followed by a fusion and stabilization with segmental pedicle
screw anchors spanning three levels above and below the level of injury.

Distraction/Extension Injuries

Distraction/extension injuries are uncommon. Patients
typically have an underlying metabolic bone disease and a preexisting
spinal deformity (i.e., ankylosing spondylitis or diffuse idiopathic
skeletal hyperostosis). Immobilization alone is inadequate because
these are highly unstable injuries with a high likelihood of
progression and neurologic worsening. Supine positioning may exacerbate
the spinal deformity and cause neurologic decline due to the existence
of a preinjury kyphotic spinal deformity. A principle of emergency
management of this spinal injury is to attempt to reproduce the
preinjury sagittal profile of the patient regardless of neurologic
status through bedding supplements or skeletal traction. When

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reduced, surgical stabilization with segmental internal fixation may be performed (Fig. 5-9).

Figure 5-9 (A) Sagittal T2-weighted MRI of a complete fracture-dislocation through the L5 vertebral body. (B)
Lateral postoperative radiograph shows adequate reduction of the
fracture-dislocation stabilized with pedicle screw instrumentation from
L4-S1.

CONCLUSION

Despite advancements in spinal implants and radiographic
imaging, controversy continues regarding the indications for surgical
intervention, the timing of intervention, and the approach with which
to correct any existing spinal deformity. Nevertheless, the basic
tenets of trauma surgery should be strictly adhered to. When the
patient is medically stabilized, a detailed neurologic exam and careful
radiographic evaluation should be performed. The surgeon should be
aware of the biomechanics of the thoracolumbar spine, the mechanism of
injury, and the various implants available for treatment. Most
thoracolumbar injuries, in the absence of a neurologic deficit, are
stable and can be treated successfully nonoperatively. For the rare
unstable spinal fracture, with or without a neurologic deficit,
surgical treatment often is beneficial in improving patient
mobilization and early functional return to society. The ultimate goals
in managing thoracolumbar injuries are to maximize neurologic recovery
and to stabilize the spine expeditiously for early rehabilitation and
an early return to a productive lifestyle.