Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.
Title: 5-Minute Orthopaedic Consult, 2nd Edition
Copyright ©2007 Lippincott Williams & Wilkins
> Table of Contents > Spine Fusion
Spine Fusion
David B. Cohen MD
Andrew P. Manista MD
BasicsDescription
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Spine fusion is a surgical procedure that causes 2 or more vertebral levels to be joined with solid bony healing in the spine.
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It is performed to correct spinal
instability from traumatic, degenerative, or iatrogenic causes and to
prevent spinal deformity progression.
Epidemiology
Incidence
Over the last 2 decades, the incidence of spinal fusion in the United States has more than doubled in the adult population (1).
Risk Factors
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Diabetes mellitus leads to increased risk of infection in patients undergoing spine fusion.
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Diabetes mellitus or tobacco use (2) leads to high rates of pseudarthrosis (nonunion).
Etiology
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Spinal fusions often are indicated for (3):
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Congenital scoliosis
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Idiopathic scoliosis
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Spondylolisthesis
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Degenerative scoliosis
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Spinal fractures
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Postsurgical instability
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DiagnosisSigns and Symptoms
Imaging
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Plain radiographs are used to assess the adequacy and maturation of a spinal fusion (4).
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The presence of continuous bridging bone over the fusion site is the best evidence of a well-healed fusion.
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When failure to heal (pseudarthrosis) is suspected, the following are indicated:
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CT scan
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3D reconstructions of a CT scan
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Conventional radiographs, often with flexion and extension views
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TreatmentGeneral Measures
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Success of an individual fusion depends on:
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Patient age
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Surgical technique
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Use of bone graft (5)
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Patient’s nutritional status
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Patient’s smoking status: Cigarette smoking can increase the rate of pseudarthrosis by up to 8-fold (2).
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Special Therapy
Physical Therapy
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Physical therapy helps increase walking ability and improve aerobic conditioning.
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It is not required after spinal fusion.
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Individual surgeon preference
Surgery
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The choice of surgical approach (anterior
or posterior) depends on the requirements of an individual case (e.g.,
the need for correction of rigid versus flexible deformities or the
need to decompress neural elements) (6). -
Fusion can be facilitated by combining
instrumentation techniques (e.g., pedicle screws, pedicle hooks,
sublaminar wires) and various types of bone graft (e.g., local, iliac
crest, rib, fibula, or allograft).
Follow-up-
During the 1st year after spinal fusion
surgery, patients require follow-up with the treating surgeon every 2–3
months for healing assessment. -
Once solidly healed, patients should be
followed every few years to monitor for developing pseudarthrosis or
problems related to early degenerative changes at levels adjacent to
the fused levels.
Prognosis
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The prognosis varies greatly, depending on:
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Diagnosis
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Smoking status
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Surgical technique
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Patients with impending litigation and
those injured at work tend to have less favorable results than patients
without these conditions (7).
P.415
Complications (8)
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Depending on the indications for surgery:
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Failure to return to normal function
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Pseudarthrosis
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Depending on the surgical technique:
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Pseudarthrosis rates of 10% are not uncommon in the literature, but not all pseudarthroses are painful or require treatment.
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Spinal fusion increases load and stresses
at levels adjacent to the fusion, a situation that can lead to an
increased rate of early degeneration at the junctional levels (9). -
Neurologic injury
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Patient Monitoring
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Activity:
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For 6 weeks after surgery (during healing
and maturation of the fusion), patients often have activity
restrictions, which vary from surgeon to surgeon. -
By 6 months after surgery, most patients
are released to unlimited activities, but most physicians advise
against high-impact activities such as running, downhill skiing, and
lifting heavy weights.
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Follow-up care:
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In general, bone is the slowest healing tissue in the human body, but it has the ability to heal completely without a scar.
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Healing of the spinal fusion is similar to fracture healing.
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Spinal instrumentation and appropriate immobilization limit the local motion, which allows a fusion to heal.
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In adults, it takes up to 6 months for a fusion to become solid and up to 2 years for it to attain full strength.
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In children, bone heals more rapidly, and full fusion strength can occur in 6–12 months.
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References
1. Deyo RA, Gray DT, Kreuter W, et al. United States trends in lumbar fusion surgery for degenerative conditions. Spine 2005;30:1441–1445.
2. Glassman SD, Anagnost SC, Parker A, et al. The effect of cigarette smoking and smoking cessation on spinal fusion. Spine 2000;25:2608–2615.
3. Hanley
EN, Jr, David SM. Who should be fused? Lumbar spine. In: Frymoyer JW,
ed. The Adult Spine: Principles and Practice, 2nd ed. Philadelphia:
Lippincott-Raven, 1997:2157–2174.
EN, Jr, David SM. Who should be fused? Lumbar spine. In: Frymoyer JW,
ed. The Adult Spine: Principles and Practice, 2nd ed. Philadelphia:
Lippincott-Raven, 1997:2157–2174.
4. Hilibrand AS, Dina TS. The use of diagnostic imaging to assess spinal arthrodesis. Orthop Clin North Am 1998;29:591–601.
5. Louis-Ugbo
J, Boden SD. Spinal fusion. In: Bono CM, Garfin SR, Tornetta P, et al.,
eds. Spine. Philadelphia: Lippincott Williams & Wilkins,
2004:297–324.
J, Boden SD. Spinal fusion. In: Bono CM, Garfin SR, Tornetta P, et al.,
eds. Spine. Philadelphia: Lippincott Williams & Wilkins,
2004:297–324.
6. Liew
SM, Simmons ED, Jr. Thoracic and lumbar deformity: Rationale for
selecting the appropriate fusion technique (anterior, posterior, and
360°). Orthop Clin North Am 1998;29:843–858.
SM, Simmons ED, Jr. Thoracic and lumbar deformity: Rationale for
selecting the appropriate fusion technique (anterior, posterior, and
360°). Orthop Clin North Am 1998;29:843–858.
7. Atlas
SJ, Chang Y, Kammann E, et al. Long-term disability and return to work
among patients who have a herniated lumbar disc: The effect of
disability compensation. J Bone Joint Surg 2000; 82A:4–15.
SJ, Chang Y, Kammann E, et al. Long-term disability and return to work
among patients who have a herniated lumbar disc: The effect of
disability compensation. J Bone Joint Surg 2000; 82A:4–15.
8. Brown CA, Eismont FJ. Complications in spinal fusion. Orthop Clin North Am 1998;29:679–699.
9. Hilibrand
AS, Carlson GD, Palumbo MA, et al. Radiculopathy and myelopathy at
segments adjacent to the site of a previous anterior cervical
arthrodesis. J Bone Joint Surg 1999;81A:519–528.
AS, Carlson GD, Palumbo MA, et al. Radiculopathy and myelopathy at
segments adjacent to the site of a previous anterior cervical
arthrodesis. J Bone Joint Surg 1999;81A:519–528.
MiscellaneousPatient Teaching
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Spinal fusion predisposes to additional spinal difficulties.
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Generalized total body fitness, avoiding
smoking, and preventing osteoporosis are important factors for
minimizing these problems.
FAQ
Q: How are spinal fusions obtained?
A:
Spinal fusions occur as a result of the process of incorporating bone
graft between adjacent spinal segments while maintaining a stable
spinal segment, often with spinal instrumentation.
Spinal fusions occur as a result of the process of incorporating bone
graft between adjacent spinal segments while maintaining a stable
spinal segment, often with spinal instrumentation.
Q: What are 2 factors that increase the rates of pseudarthrosis (nonunion) after a spine fusion.
A: Diabetes mellitus and smoking.