title: Technical difficulties and their prediction in 2-portal endoscopic carpal tunnel release for idiopathic carpal tunnel syndrome.
abstract: OBJECTIVE
  This study aimed to identify technical difficulties encountered during 2-portal endoscopic carpal tunnel release (ECTR) and to determine their incidence. Furthermore, we assessed the possibility of preoperatively predicting such technical difficulties.
  
  
  METHODS
  We retrospectively reviewed the records of 311 hands of 311 patients with idiopathic carpal tunnel syndrome who underwent ECTR with our modified Chow 2-portal technique. Any technical difficulties during the procedure were reviewed and correlated with preoperative physical findings, nerve conduction studies, and magnetic resonance imaging findings, by use of the t test, χ(2) test, and binary regression analysis.
  
  
  RESULTS
  One or more difficulties were encountered in 139 of 311 hands (44.7%), whereas surgery in the remaining 172 hands (55.3%) was performed without any difficulties. Technical difficulties encountered were as follows: tight access in 61 hands, difficulty in identifying the distal part of the transverse carpal ligament through the exit portal in 35 hands, synovial tissue being caught at the cannula tip when pulling it out of the carpal tunnel in 39 hands, steep angle of the cannula assembly with difficulty in emerging from the exit portal in 29 hands, and other difficulties. Postoperative worsening of symptoms was observed in 8 hands (2.6%), in all of which technical difficulties were encountered. Tight access was noted in younger patients and those with a small cross-sectional area at the hook-of-hamate level. The entire ECTR procedure for older female patients was more likely to be easily performed.
  
  
  CONCLUSIONS
  The surgeon may face a variety of technical difficulties during ECTR. Technical difficulties were most often encountered during introduction of the cannula assembly into the carpal tunnel and pulling it out of the exit portal. Older female patients may be the best candidates for 2-portal ECTR.
  
  
  METHODS
  Level IV, therapeutic case series.
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan. sigeuti@shinshu-u.ac.jp
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Uchiyama
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Toshiro
authors.initials: T
authors.lastname: Itsubo
authors.forename: Hironori
authors.initials: H
authors.lastname: Murakami
authors.forename: Masanori
authors.initials: M
authors.lastname: Hayashi
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Imaeda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kato
mesh_terms: D000368:Aged; D001182:Arthroscopy / Q000009:adverse effects / Q000379:methods*; D002349:Carpal Tunnel Syndrome / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies