Review Question - QID 3704

This patient has kyphosis from previous laminectomy.

The incidence of postlaminectomy kyphosis is estimated to be between 6-47%, with the highest incidence occurring in skeletally-immature children (nearly 100%). The risk is increased with preoperative kyphosis or sagittal instability and facet resection (especially >30-50%). The development of kyphosis is attributed to (1) loss of the posterior tension band with redistribution of load through the posterior facets and anterior vertebral body, and (2) loss or denervation of posterior cervical musculature.

Albert et al. reviewed postlaminectomy kyphosis. They advocate prophylactic fusion for multi-level decompressions, facet resection, skeletal immaturity, and when laminectomy is performed in a neutral (non-lordotic) spine. They advise against posterior procedures if preoperative sagittal alignment is not neutral or lordotic.

McAllister et al. review the need for fusion with laminectomy. They recommend laminectomy and fusion if there is <10 degrees of lordosis, sagittal instability, axial neck pain, young patients (<70y), no comorbidities and postop radiation is required. They recommend laminectomy alone if there is at least 10deg of lordosis, no instability or neck pain, in elderly patients (>70y) with comorbidities, and where radiation is not necessary.

Deutsch et al. discuss treatment options for postlaminectomy kyphosis. The anterior approach allows for deformity correction via either corpectomy or discectomy with disc interspace distraction. The posterior approach allows for lateral mass instrumentation, and is necessary to supplement long strut grafts and unstable spines. Corrective osteotomies (Smith-Peterson or pedicle subtraction) can also be performed to reduce kyphotic deformity. Combined anterior-posterior approaches are necessary for procedures involving more than a two-level corpectomy, or in unstable spines.

Figures A, B and C show a kyphotic spine with missing spinous processes. This indicates that there was previous cervical laminectomy. Illustration A shows a sagittal MRI demonstrating postlaminectomy kyphosis with spinal cord compression at C3. Illustration B shows the anterior bone formation with preservation of disc space consistent with DISH. Illustration C shows ossification within the disc space consistent with ankylosing spondylitis.

Incorrect Answers:
Answer 1: There is no evidence of ankylosing spondylitis.
Answer 2: There is no evidence of Occipitocervical instability.
Answer 3: There is no evidence of diffuse idiopathic skeletal hyperostosis.
Answer 4: There is no evidence of rheumatoid arthritis. Rheumatoid cervical spondylitis includes atlantoaxial subluxation, basilar invagination and subaxial subluxation.