Analysis of the learning curve for lumbar discoblock guided by C-arm fluoroscopy

English Keywords:Low back pain  Lumbar discoblock  Learning curve

English Abstract:

  【Abstract】 Objectives: The purpose of the present study was to determine the learning curve for lumbar discoblock guided by C-arm fluoroscopy using a learning curve cumulative summation test(LC-CUSUM), and compare the differences between L2-L5 and L5/S1 segment. Methods: A retrospective design was used. This study comprised 120 patients who underwent a single level lumbar discblock from October 2017 to December 2019. Patients were divided into group L2-L5 and group L5/S1 according to the operation segment and each group was operated by different orthopedic surgeon. Surgery success was defined as: operative time of group L2－L5 <20 minutes, group L5/S1 ＜25 minutes, and accordingly the acceptable procedure was completed within 5 and 7 times of C-arm fluoroscopy. The LC-CUSUM was used to analyze the data. The operative time, numbers of radioactive exposure, numbers of nerve root irritation syndromes during operation and VAS improvement rate between the two groups were compared respectively, and the differences of these indexes between the different learning stage were compared respectively either. Results: The mean operative time in the two groups was 17.9±3.7min vs 24.1±3.8min respectively(P＜0.05). The average numbers of radioactive exposure in the two groups were 5.0±1.5 vs 6.0±1.6 respectively(P＜0.05). The average numbers of nerve root irritation syndromes during operation in the two groups were 3.2±1.5 vs 4.1±1.6(P＜0.05). The mean operative time(19.2±4.2min vs 16.0±1.6min), the average numbers of radioactive exposure(5.5±1.8 vs 4.4±0.7), the average numbers of nerve root irritation syndromes(4.1±1.2 vs 1.9±1.0) between the early and late learning stage of L2-L5 segment showed significant differences respectively(P＜0.05). The mean operative time(25.3±4.0min vs 21.7±1.8min), the average numbers of radioactive exposure(6.4±1.7 vs 5.1±0.8), the average numbers of nerve root irritation syndromes(4.9±1.3 vs 2.6±1.2) between the early and late learning stage of L5/S1 segment showed significant differences respectively(P＜0.05). No significant differences were found in the VAS improvement rate of the two groups[(63.5±9.5)% vs (64.5±8.5)%, P=0.52] and the two learning stage[L2-L5: (63.8±8.9)% vs (62.6±10.5)%, P=0.65; L5/S1: (64.0±9.7)% vs (64.8±5.5)%, P=0.7]. Conclusions: The LC-CUSUM analysis demonstrated that a substantial learning period maybe necessary before an adequate level of performance is achieved for the discoblock technique guided by C-arm fluoroscopy in L2-L5 and L5/S1 segment: 33-36 and 40-44 cases respectively.