Bilateral Decompression via Microscopic TubularCrossing Laminotomy (MTCL) for Lumbar Spinal Stenosis: Technique and Early Surgical Result.

The purpose of this study was to determine the feasibility and efficacy of bilateral decompression procedure via microscopic tubular crossing laminotomy (MTCL) for treating lumbar spinal stenosis (LSS). Seventeen patients with LSS underwent bilateral decompression via an MTCL procedure in which tubular retractor was placed. The mean age was 72 (range 59-84) years and there were 10 men and 7 women. All patients underwent pre- and postoperative dynamic lumbar x-ray, magnetic resonance (MR) image, and computed tomography. To verify the efficacy of this technique, pre- and postoperative cross-sectional area (CSA) of thecal sac, facet resection, and fatty infiltration (FI) of multifidus were measured. Clinical results were evaluated using Oswestry Disability Index (ODI), back and leg visual analog scale (VAS). The mean follow-up period was 17.5 months (range 12.1-21.2). 70.5% of MTCL was performed at the level of L4-5 and one case of dural violation (5.8%) was noted at the level of L5-S1. The mean preoperative CSA was 70.5 mm(2) (range 25.1-87.6) and it increased to 198.8 mm(2) (range 177.3-219.2) postoperatively (p = 0.00). The mean facet resection rate was 18.4% (range 9.9-26.9) and no radiological instability was noted postoperatively. MR image showed no increase in FI of the multifidus after 12 months of follow-up (p = 0.53). Preoperative clinical symptoms improved significantly at postoperative 6 months and 12 months of follow-up. These results indicate that an MTCL with use of tubular retractor system can be an effective procedure to achieve neural decompression for the treatment of LSS and it may be beneficial in preserving both facet joint and multifidus muscle.