Evaluation of learning curves of uniportal coaxial large-channel and unilateral biportal endoscopic lumbar interbody fusions

English Keywords:Lumbar interbody fusion  Endoscopic  Learning curve  Uniportal  Biportal

English Abstract:

  【Abstract】 Objectives: To evaluate the learning curve difference between uniportal coaxial large-channel endoscopic lumbar interbody fusion(UCLE-LIF) and unilateral biportal endoscopic lumbar interbody fusion(UBE-LIF). Methods: The clinical data of 90 patients with lumbar degenerative diseases(LDD) treated with endoscopic lumbar interbody fusion in our hospital from October 2018 to February 2021 were retrospectively analyzed. The operations were all performed by one same surgeon. The patients were divided into UCLE-LIF group(n=45 cases) and UBE-LIF group(n=45 cases) according to the operation method, and each group was divided into 3 subgroups in accordance with the order of operation: a(cases 1-15), b(cases 16-30) and c(cases 31-45). The operative time, complications, low back and leg pain visual analogue scale(VAS) and Oswestry disability index(ODI) in each subgroup of both UCLE-LIF group and UBE-LIF group were recorded and analyzed, as well as the fusion status at 1 year follow-up; Polynomial regression model and learning curve were constructed. Results: The patients in both groups completed at least 1 year of follow-up. The operative time of subgroups a, b and c in UCLE-LIF group were 264.85±43.52min, 220.56±22.44min and 175.27±15.50min, respectively, and there was no statistical difference between subgroups a and b(P>0.05), while there was statistical difference between subgroups a and c(P<0.05); The operative time of subgroups a, b and c in UBE-LIF group were 248.32±30.42min, 185.76±18.13min and 169.17±12.26min, respectively, which differed significantly between subgroups a, b, and c(P<0.05). The incidence of surgery-related complications of subgroup a was higher than that of subgroups b and c in both two groups, but there was no significant difference between subgroups(P>0.05). There was no significant difference in the improvement of VAS score between subgroups in UCLE-LIF group(P>0.05), while the improvement of VAS score in UBE-LIF group was higher in subgroup a than in subgroups b and c, and the difference was statistically significant(P<0.05). There was no significant difference in the improvement of ODI scores between subgroups both in UCLE-LIF group and UBE-LIF group(P>0.05). According to Bridwell criteria, all subgroups achieved grade Ⅰ or Ⅱ fusion at 1 year follow-up. The learning curve polynomial regression models for UCLE-LIF group and UBE-LIF group were y=259.440e^(-0.14t)(R2=0.683) and y=274.088-6.744t+0.105t2(R2=0.878), respectively. Conclusions: Both UCLE-LIF and UBE-LIF can achieve satisfactory clinical efficacy in the treatment of LDD. UBE-LIF is steep in learning curve and easy to learn, while UCLE-LIF is relative flat in learning curve which needs a slightly longer learning cycle.