Metrx microendoscopic discectomy system

The records of 130 LSS patients who underwent minimally invasive lumbar decompression surgery were retrospectively reviewed to investigate the clinical impact of RLS on the outcomes after surgery. All patients underwent bilateral decompression via a unilateral approach to decompress the central and bilateral lateral recess using a microscope or the METRx^® Microendoscopic Discectomy System (Medtronic, Dublin, Ireland) as previously described [25 (link),26 (link)]. Clinical outcomes were evaluated with the Japanese Orthopaedic Association (JOA) score and visual analog scale (VAS) score for lower back pain, leg pain, and leg numbness preoperatively and at the last follow-up. The JOA score was developed by the JOA to measure outcomes for patients with lower back problems. It consists of 29 points and has been widely utilized to evaluate the functional results of many types of intervention for patients with lumbar disorders [27 (link)]. The improvement rate for the JOA scores was calculated as: (postoperative JOA score−preoperative JOA score)/(29−preoperative JOA score) × 100 (%) [28 (link)].

All patients underwent bilateral decompression via a unilateral approach to decompress the central and bilateral lateral recess using a microscope or the METRx Microendoscopic Discectomy System (Medtronic Sofamor Danek, Warsaw, Indiana, USA), performed as previously described^{9 (link),10 (link)}. The radiological indications were LSS, degenerative lumbar spondylolisthesis (DS) with a Meyerding grade ≤1 and a posterior opening ≤5° during anterior flexion of the affected intervertebral level and degenerative lumbar scoliosis (DLS) with a Cobb’s angle ≥10° or ≤20°. Laminotomy was performed on the side of the approach in the area of the ligamentum flavum insertion, and resection of the articular process was performed in a trumpeted manner until the inner aspect of the pedicle, with slight tilting of the microscope or tubular retractor laterally. Laminotomy was performed on the approach side using an air drill, Kerrison rongeur and an osteotome. Decompression was then performed on the contralateral side after tilting the operating table and the microscope or the tubular retractor.