Postlaminectomy Kyphosis in the Skeletally Immature Achondroplast

STUDY DESIGN: Retrospective review. OBJECTIVES: To determine the risk of postlaminectomy thoracolumbar kyphosis in skeletally immature achondroplasts and evaluate the need for concurrent fusion at multilevel decompression. SUMMARY OF BACKGROUND DATA: Spinal stenosis is a relatively common complication of achondroplasia. Although most achondroplasts do not develop symptomatic spinal stenosis until the third or fourth decades, some patients become symptomatic before skeletal maturity. While postlaminectomy kyphosis typically does not occur in the adult achondroplast, it is not known if it occurs in the skeletally immature achondroplast. METHODS: The charts and radiographs of 10 consecutive skeletally immature achondroplasts that underwent surgical treatment for symptomatic spinal stenosis during a 10-year period were retrospectively reviewed. The average age of the 6 male and 4 female patients at surgery was 9.2 years (range 6-16). All patients had preoperative lateral radiographs. Decompression consisted of multilevel (5-8) thoracolumbar laminectomies. More than 50% of each medial facet was preserved bilaterally to maintain spinal stability. RESULTS: Postlaminectomy thoracolumbar kyphoses developed in all 10 patients (100%). The postlaminectomy kyphoses ranged from 78 degrees to 135 degrees (mean 94 degrees ). All patients underwent spinal fusions with instrumentation, performed from 10 months to 2.6 years after the decompressions, to stabilize the kyphoses. CONCLUSIONS: Skeletally immature achondroplasts are at high risk for developing postlaminectomy thoracolumbar kyphoses. Therefore, concurrent spinal fusion is indicated in skeletally immature achondroplasts who undergo thoracolumbar laminectomies of at least 5 levels.