Controlled clinical trial on whether or not to reserve ligament flavum in micro endoscopy discectomy

Objective To discuss clinical results and effect on epidural fibrosis of preservation of ligament flavum in micro endoscopy discectomy (MED). Methods From January 2005 to January 2011, 206 cases which med the inclusion and exclusion criteria were treated by retrospective study method and were divided into two groups. A group was treated with standarded operation in MED; B group was treated with remaining ligament flavum in MED. The visual analogue scale(VAS), Oswestry disability index(ODI), and angle of straight leg raising(SLR) were recorded 1 day before and 4 weeks after operation. The early curative effect evaluation was achieved in the 4th week. The questionnaire survey was conducted and CT was used to evaluate epidural fibrosis and recorded score 1 year after operation. Results One day before operation, VAS, ODI, and SLR in A group and B group were 7.75±1.23 and 7.84±1.27, 71.8%±9.4% and 72.3%±9.1%, 25.1°±2.33° and 24.6°±2.28°, (50.59±5.59)min and (51.03±6.18)min, (43.56±8.02)mL and (42.88±8.76)mL, respectively. There were no statistical differences (t=0.512, 0.386, 0.893, 0.529, 0.574, respectively, all P values>0.05). There were no statistical differences in intraoperative complication and postoperation complication between A group and B group (χ2=0.042, 0.042, respectively, all P values>0.05). Four weeks after operation, VAS, ODI, and SLR in A group and B group were 3.13±1.24 and 2.32±1.20, 29.4%±6.7% and 23.3%±7.6%, 65.2°±4.84°and 74.4°±4.92°, respectively. There were, statistically significant differences (t= 4.741, 6.025, 13.423, respectively, all P values<0.01). On early curative effect evaluation, A group was better than B group(Z=-3.058, P<0.01). On CT score, mean of A group was 1.80, mean of A group was 1.15(Z=-5.435, P<0.05). Conclusions Whether or not to preserve ligament flavum in discectomy in MED, clinical symptoms have great improvement when compared with its own. While the operation of remaining ligament flavum has better outcome, less epidural fibrosis. Key words: Diskectomy, percutaneous; Intervertebral disc displacement; Micro endoscopic; Ligamentum flavum; Dura mater; Fibrosis