Long Term Clinical and Radiographic Results of Lumbar Spinal Stenosis with Grade I Degenerative Spondylolisthesis after Microsurgical Bilateral Decompression via Unilateral Laminotomy

ABSTRACT

OBJECTIVE: The purpose of this study was to assess long-term clinical outcomes and radiographic changes in patients with lumbar spinal stenosis with grade I degenerative spondylolisthesis who underwent microsurgical bilateral decompression via unilateral laminotomy, as a minimally invasive surgery. Method: Medical records of twenty-five patients who underwent the surgery between 1999 and 2005 were retrospectively evaluated. Clinical outcomes were evaluated through interviews over telephone with standardized questionnaires. Preoperative and postoperative radiographs were taken from all patients in neutral and dynamic lateral views. The mean follow-up period after surgery was 38.5 months(range 9-57 months). RESULTS: Seventy-two percent of patients were either pain free(48%) or doing well with occasional acetaminophens(24 %), and satisfied with the treatment. The most improved preoperative symptom was neurogenic intermittent claudication, which was ameliorated in 94.7% of patients(excellent 84.2%, good 10.5%, fair 5.3%). Postoperative vertebral slippage was also measured and appeared to be slightly increased but this was not statistically significant. Postoperative dynamic angulation did not change significantly compared to the preoperative value. CONCLUSION: Microsurgical bilateral decompression via unilateral laminotomy achieved a satisfactory decompression and symptomatic relief without extensive destruction of the weight-bearing structures and functional mobile segments. This treatment can be an effective modality for patients with lumbar spinal stenosis associated with mild degenerative spondylolisthesis.