[Retrospective study of complication of interspinous implants for degenerative lumbar disease]

To summarize and analyze the complications of interspinous implants for degenerative lumbar disease.

From September 2007 to September 2011, 177 cases with degenerative lumbar diseases were treated with interspinous implants. There were 99 male patients and 78 female patients, the average age was 44.5 years (26 - 71 years). According to the application interspinous dynamic stabilization system type were divided into the Wallis group (136 cases) and Coflex group (41 cases). The clinical results were assessed by visual analog scale (VAS) of pain on lumbar and lower limbers, lumbar Japanese Orthopedic Association (JOA) score and Prolo functional score. The radiological results including segmental lodosis and segement movement degree were assessed by lumbar X ray and dynamic X ray. Summarize and analyze the complications both during operation and post operation. Quantitative datas were compared by paried-samples t test and complication rate was compared by χ(2) test.

There were 168 cases had completed follow-up and the average time was 34.7 months (3 - 50 months). In the final follow-up, lumbar pain VAS, lower limber pain VAS, lumbar JOA score and Prolo functional score were better than pre-operation (t = 10.7, 7.9, 13.4 and 8.8, P < 0.01). Segment lodosis angles was 14° ± 4° which was less than pre-operation 19° ± 4° (t = 9.4, P < 0.01).Segment movement degree was larger in Coflex group (12.6° ± 3.1°) than in Wallis group (9.7° ± 2.7°) (t = 8.6, P < 0.05). Complication rate was 10.7% (18/168), which of Wallis group was 6.2% (8/130) and Coflex group was 26.3% (10/38) (χ(2) = 12.5, P < 0.01). In Wallis group, there were 3 cases with dura tear and cerebrospinal fluid leakage, 1 case with nerve root injury and foot drop, 2 cases with spacer breakage when implantation and change the implants and 2 cases with recurrence of lumbar disc herniation. In Coflex group, there was 1 case with dura tear and cerebrospinal fluid leakage, 2 cases with mild displacement post operation, 1 case with debridement for aseptic wound exudates, 1 case with implant removal for breakage 1 week post operation, 4 cases with recurrence of lumbar disc herniation and 1 case with lumbar disc herniation 6 months post operation of lumbar stenosis.

The application of interspinous implants for degenerative lumbar diseases is effective and relative safe, but would suffer from the risk of complications.