Proximal Segment Degeneration Following Posterior Lumbosacral Fusions (L4-S1 and L5-S1)

Controversy exists regarding the degeneration of adjacent segments following posterior spinal fusion. The purpose of this study was to determine the survivorship of proximal segments after lumbosacral fusions.

Fifty-five patients having L4-S1 and 30 patients having L5-S1 posterior spinal fusions by a single surgeon were included in this study. Average follow-up was 6.9 years.

Sixty-three patients did not require additional surgery. Two patients developed spinal stenosis and underwent decompressions approximately 14 years postoperatively. Twenty patients required further fusion surgery an average of 11 years postoperatively. Thirteen patients underwent fusion extension to the immediately proximal level, 5 required extension two levels proximally, and 2 underwent fusion ending distally at L3. The most common cause for reoperation was adjacent segment degeneration.

Adjacent segment disease is a concern following lumbosacral posterior spinal fusion. At an average follow-up of 6.9 years, 26% of patients required reoperation, with 91% needing proximal lumbar fusions.