ORIGINAL ARTICLE Does Wallis implant reduce adjacent segment degeneration above lumbosacral instrumented fusion?

Abstract Delayed complications following lumbar spine fusion may occur amongst which is adjacent segment degeneration (ASD). Although interspinous implants have been successfully used in spinal stenosis to authors’ knowledge such implants have not been previously used to reduce ASD in instrumented lumbar fusion. This prospec-tive controlled study was designed to investigate if the implantation of an interspinous implant cephalad to short lumbar and lumbosacral instrumented fusion could elimi-nate the incidence of ASD and subsequently the related re-operation rate. Groups W and C enrolled initially each 25 consecutive selected patients. Group W included patients, who received the Wallis interspinous implant in the unfused vertebral segment cephalad to instrumentation and the group C selected age-, diagnosis-, level-, and instrumentation