Object: The authors undertook this study to document the clinical outcomes of microendoscopic laminotomy, a minimally invasive decompressive surgical technique using spinal endoscopy for lumbar decompression, in patients with lumbar spinal stenosis (LSS).
Methods: A total of 366 patients were enrolled in the study and underwent microendoscopic laminotomy between 2007 and 2010. Indications for surgery were single- or double-level LSS, persistent neurological symptoms, and failure of conservative treatment. Microendoscopy provided wide visualization through oblique lenses and allowed bilateral decompression via a unilateral approach, through partial resection of the base of the spinous process, thereby preserving the supraspinous and interspinous ligaments and contralateral musculature. Clinical symptoms and signs of low-back pain were evaluated prior to and following surgical intervention by applying the Japanese Orthopaedic Association (JOA) scoring system, Roland-Morris Disability Questionnaire (RMDQ), Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), and 36-Item Short Form Health Survey (SF-36). These items were evaluated preoperatively and 2 years postoperatively.
Results: Effective circumferential decompression was achieved in all patients. The 2-year follow-up evaluation was completed for 310 patients (148 men and 162 women; mean age 68.7 years). The average recovery rate based on the JOA score was 61.3%. The overall results were excellent in 34.9% of the patients, good in 34.9%, fair in 21.7%, and poor in 8.5%. The mean RMDQ score significantly improved from 11.3 to 4.8 (p < 0.001). In all categories of both JOABPEQ and SF-36, scores at 2 years' follow-up were significantly higher than those obtained before surgery (p < 0.001). Twelve surgery-related complications were identified: dural tear (6 cases [1.9%]), wrong-level operation (1 [0.3%]), transient neuralgia (4 [1.3%]), and infection (1 [0.3%]). All patients recovered, and there were no serious postoperative complications.
Conclusions: Microendoscopic laminotomy is a safe and very effective minimally invasive surgical technique for the treatment of degenerative LSS.