Operative treatment of the degenerated segment adjacent to a lumbar fusion.

Fourteen patients with a previous lumbosacral fusion underwent neural decompression and fusion of degenerated adjacent motion segment. The most common level was L3-L4, and there was an average of 3.2 (range 1-7) previous lumbosacral surgical procedures. The average interval from the first fusion until operative intervention on the degenerated adjacent segment was 11.5 years (range 3-29 years). Five patients had an uninstrumented fusion, of which only one progressed to arthrodesis. Three of these five patients with pseudarthrosis after uninstrumented fusion--and the remaining nine patients--had fusions with instrumentation. Ten of twelve instrumented fusions progressed to solid arthrodesis. The pseudoarthrosis rate of 80% was decreased to 17% with the use of supplemental instrumentation. There was a significant number of complications and poor results, especially in patients with advanced osteoporosis and those with a short interval between adjacent segment degeneration, respectively. Eleven of 14 patients reported some postoperative pain relief.