title: Learning curves of percutaneous endoscopic lumbar discectomy in transforaminal approach at the L4/5 and L5/S1 levels: a comparative study.
abstract: OBJECTIVE
  This study aimed to compare the learning curves of percutaneous endoscopic lumbar discectomy (PELD) in a transforaminal approach at the L4/5 and L5/S1 levels.
  
  
  METHODS
  We retrospectively reviewed the first 60 cases at the L4/5 level (Group I) and the first 60 cases at the L5/S1 level (Group II) of PELD performed by one spine surgeon. The patients were divided into subgroups A, B, and C (Group I: A cases 1-20, B cases 21-40, C cases 41-60; Group II: A cases 1-20, B cases 21-40, C cases 41-60). Operation time was thoroughly analyzed.
  
  
  RESULTS
  Compared with the L4/5 level, the learning curve of transforaminal PELD at the L5/S1 level was flatter. The mean operation times of Groups IA, IB, and IC were (88.75±17.02), (67.75±6.16), and (64.85±7.82) min, respectively. There was a significant difference between Groups A and B (P<0.05), but no significant difference between Groups B and C (P=0.20). The mean operation times of Groups IIA, IIB, and IIC were (117.25±13.62), (109.50±11.20), and (92.15±11.94) min, respectively. There was no significant difference between Groups A and B (P=0.06), but there was a significant difference between Groups B and C (P<0.05). There were 6 cases of postoperative dysesthesia (POD) in Group I and 2 cases in Group IIA (P=0.27). There were 2 cases of residual disc in Group I, and 4 cases in Group II (P=0.67). There were 3 cases of recurrence in Group I, and 2 cases in Group II (P>0.05).
  
  
  CONCLUSIONS
  Compared with the L5/S1 level, the learning curve of PELD in a transforaminal approach at the L4/5 level was steeper, suggesting that the L4/5 level might be easier to master after short-term professional training.
authors.affiliation: Orthopedic Department, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.
authors.forename: Xin-Bo
authors.initials: XB
authors.lastname: Wu
authors.affiliation: Orthopedic Department, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.
authors.forename: Guo-Xin
authors.initials: GX
authors.lastname: Fan
authors.affiliation: Orthopedic Department, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Gu
authors.affiliation: Orthopedic Department, the Chinese People's Liberation Army No. 98 Hospital, Huzhou 313000, China.
authors.forename: Tu-Gang
authors.initials: TG
authors.lastname: Shen
authors.affiliation: Orthopedic Department, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.
authors.forename: Xiao-Fei
authors.initials: XF
authors.lastname: Guan
authors.affiliation: Orthopedic Department, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.
authors.forename: An-Nan
authors.initials: AN
authors.lastname: Hu
authors.affiliation: Orthopedic Department, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.
authors.forename: Hai-Long
authors.initials: HL
authors.lastname: Zhang
authors.affiliation: Orthopedic Department, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.
authors.forename: Shi-Sheng
authors.initials: SS
authors.lastname: He
mesh_terms: D000328:Adult; D017587:Diskectomy, Percutaneous / Q000193:education* / Q000379:methods; D005260:Female; D006801:Humans; D059032:Learning Curve; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D064232:Visual Analog Scale
keywords: Learning curve; Percutaneous endoscopic lumbar discectomy; Transforaminal approach