Adjacent Segment Failure above Lumbosacral Fusions Instrumented to L1or L2

Purpose: Adjacent segment degeneration has been recognized as a problem in lumbar fusion surgery. Little has been reported on adjacent segment degeneration as it relates to the level of lumbar fusion. This review was designed to evaluate the rate of adjacent segment problems in patients with instrumented lumbar fusions from the sacrum to L2.

Methods: 20 adult patients from 1994-2001 who underwent lumbosacral fusions from the sacrum to L1 or L2 for a variety of spinal pathologies including degenerative spinal stenosis and scoliosis, postlaminectomy syndrome, pseudarthrosis, and spondylolisthesis were retrospectively reviewed from a prospectively gathered computerized database. Clinical outcomes, including reoperations, and radiographic analysis was performed for all patients with a minimum two year follow up or reoperation.

Results: Reoperations were required in 7 patients, 4 for fracture at or above the most superior instrumented vertebra, 2 for adjacent segment degeneration and spinal stenosis, 1 for infection. One other patient had a pedicle fracture above his fusion treated nonperatively, and two more patients have developed symptomatic adjacent segment degeneration requiring further nonoperative care. Only two patients had a good or excellent clinical result.

Conclusion: Instrumented lumbosacral fusions that begin at L1 or L2 have an unacceptably high mechanical failure rate in adult patients and cannot be recommended at this time.