Mid-term Results of Posterior Decompression for Spinal Stenosis due to Degenerative Lumbar Spondylolisthesis

Abstract

Objective:The purpose of this study was to evaluate radiological and clinical results in patients with lumbar spinal canal stenosis due to degenerative spondylolisthesis who had undergone posterior decompressive surgery without fusion. We report our findings in 31 patients who were followed for at least 3 years after surgery. Patients and methods:We evaluated 31 consecutive patients who underwent posterior decompressive surgery without fusion between 2001 and 2005. The mean follow-up was 62.3 months. Clinical results were evaluated using the Japanese Orthopaedic Association(JOA)score and the recovery rate. The radiographic parameters we assessed were the change in % slip and the slip angle on lateral neutral films, and translation and dynamic angulation on lateral flexion and extension films obtained before and after surgery. Results:The symptom recovery rate assessed with the JOA scoring system was 76.6%. There was no statistically significant difference between preand postoperative measurements with respect to the slip angle, translation, and dynamic angulation. The postoperative % slip was statistically larger than the preoperative value(p<0.01), although the progression of slippage and instability after surgery did not affect the clinical results. We performed reoperation in 2 patients(6.5%); they underwent posterior decompression. None of the 31 patients required secondary fusion. Conclusion:In the mid-term we obtained good operative results in patientswho had undergone decompression without fusion to treat lumbar spinal canal stenosis due to degenerative spondylolisthesis. Our findings suggest that posterior decompression wide enough to reach the lateral recesses but performed without damage to the articular processes does not routinely require spinal fusion and provides satisfactory clinical results. (Received:July 29, 2008;accepted:April 6, 2009)