Wednesday, September 26, 2018 1:00 PM – 2:00 PM What's New in MIS: 40. Clinical and radiological outcomes of unilateral biportal endoscopic decompression by 30° endoscopy in lumbar spinal stenosis: minimum 2-years follow-up

Abstract

BACKGROUND CONTEXT Open laminectomy or open laminectomy and lumbar spinal fusion has been regarded as the standard surgical method to date in degenerative spinal stenosis. The conventional method has been associated with complications such as paraspinal muscle damage, bleeding and infection. Several surgical techniques including microendoscopic decompression have been introduced to solve these problems. PURPOSE The aim of this study is to introduce a new spinal surgical technique using a 30° endoscopy through unilateral biportal endoscopic decompression technique and to report the results of patients who have been on follow-up for more than 2 years. STUDY DESIGN/SETTING Retrospective study. PATIENT SAMPLE Fifty-five patients who were suffering from neurologic symptoms by degenerative lumbar spinal stenosis were included even after preoperative conservative treatment. Patients with foraminal stenosis requiring an extraforaminal approach were excluded from the study. OUTCOME MEASURES Clinical outcomes were analyzed in view of modified-Macnab criteria, Oswestry Disability Index (ODI), Visual Analog Scale (VAS), and postoperative complications were analyzed. Plain X-ray studies before and after surgery were compared to confirm disc height reduction and progression of spondylolithesis. METHODS Two or three portals were used for each level. One portal was used for viewing, the others, for working of certain instruments. Unilateral laminotomy was followed by bilateral decompression under 30° endoscopy. RESULTS Eighty-one percent of the patients improved over a level based on the Macnab criteria. There were not any case of infection. The interverbral angle was significantly reduced from 6.26±3.54° to 5.58±3.23° at 2 years postoperatively, the dynamic intervertebral angle was slightly decreased by 6.54±3.71° at 6.76±3.59°, but was not statistically significant. No significant change in percentage slip was observed (3.76±5.01% preoperatively vs. 3.81±5.28% at the last follow-up). The dynamic percentage slip (gap in percentage slip between flexion and extension X-ray exams) did not change significantly from 2.65±3.37 to 2.76±3.71%. However, at 2 years postoperatively, intervertebral distance was significantly reduced from 10.43±2.23 mm to 10.0±2.24 mm. CONCLUSIONS Full endoscopic decompression using 30° endoscopy demonstrated a satisfactory clinical outcome after surgery. This technique was able to reduce infection, and was a good procedure without postoperative segmental instability. It could be alternative method of microscopic decompression. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.