The degree of decompressive relief and its relation to clinical outcome inpatients undergoing surgery for lumbar spinal stenosis

Study Design. A cross-sectional, clinical study to evaluate surgical decomp ression of the stenotic area monitored by computed tomographic scan and its relation to clinical variables in patients operated on for lumbar spinal s tenosis. Objective. To study in patients with lumbar spinal stenosis the influence o f the degree of compressive relief on the patients' clinical outcome. Summary of Background Data. The goal of surgical treatment in lumbar spinal stenosis is to decompress the stenotic area. Although the decompression sh ould be adequate, there are no clear guidelines to determine the extent of necessary decompression. In fact, there is clinical evidence that there is a discrepancy between the surgical outcome in the patient with lumbar spina l stenosis and postoperative radiologic findings. Methods. In 92 patients with lumbar spinal stenosis who had had no prior ba ck surgery, preoperative and postoperative computed tomographic scans were obtained to determine the degree of decompression. The postoperative scan f indings were classified according to the degree of decompression into a no- stenosis group (n = 35), an adjacent-stenosis group (n = 27), and a residua l-stenosis group (n = 30), The postoperative instability of the lumbar spin e was investigated by functional radiography. The subjective disability of the patients was assessed using the Oswestry score and the severity of pain using the visual analog scale. Walking capacity was evaluated by a treadmi ll test. The patients' estimations of the results of surgery were classifie d into groups of satisfied patients and dissatisfied patients. Results. The mean Oswestry score in all 92 patients was 27.1, and mean walk ing capacity was 630 m. In the satisfied patients, the Oswestry score was 1 8.8 and in the dissatisfied patients, 34.9 (P < 0.0000). Walking capacity w as 690 m and 594 m, respectively. There were 30 patients with postoperative spinal instability, but it had no influence on surgical outcome. There wer e no differences in the Oswestry score, walking capacity, and patients' sat isfaction among the postoperative CT groups. In the linear regression analy sis, the satisfied patient corresponded significantly with the Oswestry sco re. Conclusions. The satisfaction of the patients with the results of surgery w as more important in surgical outcome than the degree of decompression dete cted on computed tomographic scan.