Instrumented slip reduction and fusion for painful unstable isthmic spondylolisthesis in adults

Background Context: Although in situ posterolateral fusion is considered the gold standard for surgical treatment of low-grade adult spondylolisthesis, correction of the sagittal translation by instrumented slip reduction is more controversial in adults; nevertheless it may delay adjacent level disc degeneration. Purpose: The present study was undertaken to evaluate the safety and clinical outcome of operative instrumented slip reduction in 12 adults with isthmic spondylolisthesis accompanied by advanced disc degeneration at that level. Study Design: This study was a retrospective review of 12 consecutive lumbar or lumbosacral isthmic slip, which underwent operative slip reduction in our institute. Patient Sample: All adult patients having operative instrumented slip reduction of isthmic spondylolisthesis from January 2000 to December 2005 were assessed. Outcome Measures: Outcome measures included the Oswestry Disability Index (ODI) for low back pain and the visual analog scale (VAS) of back and leg pain. Patient outcome was assessed by work status, participation in sports activities and intake of pain medications. Methods: Between January 2000 and December 2005, we performed slip reduction on 12 adults aged 28 to 62 years (average 47) with symptomatic lumbar or lumbosacral isthmic spondylolisthesis. The indications for surgery were long-standing low back and leg pain that had not responded to nonoperative management. Results: The vertebral slip ranged between 15% and 90% (average 34%). Radiologic evidence of adult slip progression was available in 5 patients, one had a de novo slip formation and the others had increased sagittal translation on flexion-extension lateral x-rays. All 12 patients underwent posterior decompression, pedicle screw fixation, slip reduction, and posterior lumbar interbody fusion. The slip was anatomically reduced by 100% in 5 patients and between 90% and 95% in 7 (average 95% for the group). X-rays revealed no evidence of instrumentation failure at a mean follow-up of 38 months (range: 18 to 72). Minimal loss of correction (5%) was observed in 2 cases. No neurologic complications were encountered. The mean preoperative ODI of 49 dropped to 12 postoperatively (range: 0 to 20). The mean preoperative VAS for back pain of 7.3 dropped to 1.6 after surgery (range: 0 to 3). The mean preoperative VAS for leg pain of 8 dropped to 1 after surgery (range: 0 to 4). Five patients were followed for more than 3 years: none had evidence of adjacent level disc disease. Conclusions: Our results may support performing slip reduction in selected adults with isthmic spondylolisthesis.