Surgical outcomes of a modified Marmot operation with transverse cutting of the spinal process in patients with degenerative lumbar spinal stenosis

Abstract

ObjectiveThe authors developed a minimally invasive spinal surgery technique—a microscope-assisted modified Marmot operation combined with transverse cutting of the spinal process—to increase surgical field exposure and improve surgical outcomes in patients with degenerative lumbar spinal stenosis. Materials and methodsWe retrospectively analyzed 45 patients with degenerative lumbar spinal stenosis who underwent a microscope-assisted modified Marmot operation combined with spinal process transverse cutting laminectomy from February 2009 to June 2011. Pre- and postoperative evaluations of the patients were conducted using the Oswestry Disability Index (ODI) questionnaire and visual analog scale (VAS) scores for back pain. Operation time, blood loss, and postoperative time until ambulation were also measured. ResultsThe age of the patients was 68.2 ± 7.2 years. The follow-up period was 15.3 ± 4.5 months. The postoperative hospital stay was 3.5 ± 2.2 days. The VAS scores of low back pain and leg pain were 72.1 ± 18.3 mm and 75.6 ± 20.1 mm preoperative, and 18.6 ± 17.3 and 23.8 ± 14.6 postoperative, respectively. The ODI questionnaire scores before and after the operation were 63.1 ± 6.8 and 26.5 ± 5.0, respectively. Patients had significant improvement in both VAS and ODI questionnaire scores after surgical decompression (p < 0.05). Operation time was 134.2 ± 19.6 minutes. Intraoperative blood loss was 66.5 ± 35.3 mL. No perioperative complication such as dural tear, hematoma, surgical site infection, or neurological deterioration was noted. All patients were able to walk within 2.4 ± 1.5 days. ConclusionsA microscope-assisted modified Marmot operation combined with spinal process transverse cutting laminectomy was an effective procedure for spinal decompression. As the procedure produces only unilateral muscular trauma, patients can ambulate early. Overall, the procedure is safe and effective. It provides good surgical field exposure and satisfactory neurological and functional outcomes.