Is selective nerve root block necessary for learning percutaneous endoscopic lumbar discectomy: a comparative study using a cumulative summation test for learning curve

Purpose The aim of this study was to investigate the effect of lumbar spine selective nerve root block (SNRB) experience on the learning efficiency of percutaneous endoscopic lumbar discectomy (PELD) for junior trainees. Methods A total of 480 patients undergoing single-level PELD performed by eight junior trainees were included. The trainees were divided into two groups based on whether they had previous SNRB experience (group A, yes; group B, no). Surgical proficiency was defined as total operation time less than 65 minutes and cumulative radiation exposure time no more than 40 seconds. The learning curve was analyzed by cumulative summation (CUSUM) test. Clinical evaluations included Macnab classification, visual analog scale (VAS)-low back score, VAS-leg score, and Oswestry Disability Index (ODI). Follow-up information at 12 months was also obtained. Results Integral number of cases before achieving an acceptable surgical level in group A (47.75 ± 2.50 cases) was significantly smaller than that in group B (56.50 ± 1.29 cases, p < 0.05), along with less accumulated failure (18.75 ± 0.96 cases vs. 25.50 ± 1.75 cases, p < 0.05). The two groups were comparable in clinical outcomes. Forty-seven cases of complications were observed, with 17 in group A and 30 in group B ( p < 0.05). Conclusion Previous experience of SNRB improved the performance of PELD with shorter operation time and less radiation exposure. SNRB practice may reduce the complication rate without a significant effect on the recurrence of symptoms and reoperation.