Bilateral decompression via unilateral fenestration and interbody fusion for complex lumbar spinal stenosis with mobile microendoscopic discectomy technique

Objective To evaluate the feasibility and clinical efficacy of bilateral decompression via unilateral fenestration and interbody fusion for complex lumbar spinal stenosis with mobile microendoscopic discectomy (MMED) technique. Methods Sixty-eight complex lumbar spinal stenosis patients with an average age of 67 years old (range, 56-76), including 39 men and 29 women, were treated by this procedure using MMED technique. Among them, 49 and 19 of these patients had degenerative spondylolisthesis and scoliosis respectively. All patients complained of lumbar or leg pain combined with intermittent claudication, and the index levels L4, 5 involved in 57 patients, L5S1 in 6 patients, L3-L5 in 4 patients and L4-S1 in 1 patient. Pre-operative Oswestry disability index (ODI) was 43.8%±10.4%, visual analogue scale (VAS) 6.3±3.3 for lumbar pain, and 6.1±3.8 for leg pain. Through a 2.5-3.5 cm incision medial to puncture sites of pedicle, unilateral fenestration and bilateral decompression was performed under MMED, and the disc space was curetted and prepared adequately. The inner tube was removed, and the disc space was released, tested and grafted, followed by suitable cage, whose position was confirmed under fluoroscopy. Percutaneous transpedicular screws were installed under fluoroscopy, followed by reduction and fixation. The operative time and blood loss were recorded, and the patients were followed to evaluate the clinical results. Results Surgery was successful in all patients, without nerve injury or conversion to open surgery. The mean operative time was 120 min (range, 100-180 min), with a mean blood loss of 100 ml (range, 50-200 ml). The post-operative X-ray and CT scans showed sufficient decompression and improvement of spinal alignment, with the ratio of spondylolisthesis improved from 17.9±6.2 to 11.8±4.8. All patients were followed up for more than 6 months, while 61 of them were followed for 12-24 months, with ODI score of 8.9±7.4, VAS of lumbar 1.2±1.1 and VAS of leg 0.9± 0.9 at final follow-up, that were significantly decreased compared to pre-operative scores. The clinical results were excellent in 41 cases, good in 25, and fair in 2 based on the MacNab scale. Conclusion Complex lumbar spinal stenosis can be treated by bilateral decompression via unilateral fenestration and interbody fusion with MMED technique. This procedure can also provide satisfactory results in short-term follow-up. Key words: Lumbar vertebrae; Spinal stenosis; Decompression, surgical; Spinal fusion; Surgical procedures, minimally invasive