Minimally Invasive Microscopic Decompression with Tubular Retractor System in Lumbar Spinal Stenosis - Results Comparing with Open Microscopic Decompression -

Abstract

Purpose: To compare the two methods of decompression using a microscope with a tubular retractor system and open microscopic decompression in lumbar spinal stenosis. Materials and Methods: The records of patients that had undergone decompression from May 2000 to April 2005 were reviewed. The average follow-up period was 29 months (460 months). The duration of hospital stay, estimated blood loss, relief of pain, and operating time were reviewed retrospectively. Analysis was conducted by telephone interview and chart review (McNab’s criteria). Preand post-operative Visual Analogue Scale (VAS) scores and JOA scores were also evaluated. Results: Of the total 53 patients, open microscopic decompression was performed on 27 patients, and 26 patients received surgery using microscopic decompression with tubular retractors. There were no patients who had serious complications such as infection or nerve root injury in either of the groups. The average estimated blood loss was 205 cc for the open microscopic decompression group versus 120 cc in the minimally invasive microscopic decompression (MIMD) group (p=0.019). The mean operating time was 2.5 hours in the open microscopic decompression group and 2.2 hours in the MIMD group (p=0.048). As shown by the clinical results, good or excellent results were shown by the McNab’s criteria after operation, 85.1% for the open microscopic decompression group and 94.7% for the MIMD group, respectively. The JOA score improved after surgery, with average scores of 14.5 to 24.5 in the open microscopic decompression group, and 15.9 to 25.6 in the MIMD group. The VAS score was reduced after surgery, with an average score of 8.0 to 3.7 in the open microscopic decompression group, and 8.3 to 2.6 in the MIMD group. Conclusion: In terms of blood loss, the MIMD group showed significantly better results than the open microscopic decompression group. The clinical results showed no statistically significant difference between the two groups.