Indirect Decompression for the Treatment of Degenerative Lumbar Stenosis.

backgroundSurgical treatment of symptomatic lumbar stenosis has traditionally included laminectomy for direct decompression. With increasing options for lumbar interbody fusion, there has been growing interest in indirect decompression to treat degenerative stenosis. The primary purpose of this study was to determine whether indirect decompression via anterior lumbar interbody fusion (ALIF) can provide symptomatic relief in patients with lumbar spinal stenosis. Secondary purposes were to (1) identify risk factors for failure of indirect decompression and (2) to identify risk factors for failure to obtain relief and to compare outcomes between patients undergoing stand-alone ALIF versusand those in whom ALIF was supplemented with posterior instrumentation.

methodsChart review was performed on a consecutive series of 568 patients undergoing single-level ALIF without posterior decompression to treat degenerative stenosis during a 5-year period. Failure of indirect decompression was defined as return to the operating room for direct decompression. Subgroup analysis was performed to compare patients who underwent stand-alone ALIF (n = 247) vs those in whom supplemental posterior instrumentation was used (ALIF + PI; n = 321).

resultsReoperation due to failure of indirect decompression occurred in 4.0% (23/568) of patients. The only factor related to failure was age. Patients older than 60 years were more likely to fail indirect decompression than were younger patients (7.0% vs 3.1%,

conclusionsIndirect decompression via ALIF was effective in treating appropriately selected patients with degenerative lumbar spinal stenosis. Older patients are at higher risk for failure of indirect decompression-potentially because of greater osseous stenosis as well as subsidence due to age-related diminished bone density with subsequent loss of distraction. LEVEL OF EVIDENCE: 4. CLINICAL RELEVANCE: This study supports that indirect decompression via ALIF is a viable alternative to direct decompression in appropriately selected patients with degenerative stenosis.