title: Ultrasound measurement of median nerve cross-sectional area at the inlet and outlet of carpal tunnel after carpal tunnel release compared to electrodiagnostic findings.
abstract: BACKGROUND
  Ultrasound measurement of the cross-sectional area (CSA) of the median nerve can give information about regeneration of the nerve after carpal tunnel release (CTR), but the changes at selected follow-up points up to 1 year compared to electrodiagnostic findings are not known. We postoperatively measured the CSA of the median nerve with ultrasound and compared the measurements with electrophysiological findings over 12 months after open CTR.
  
  
  METHODS
  In 21 hands that underwent open CTR, the CSA of the median nerve was measured at the inlet (proximal CSA) and outlet (distal CSA) of the carpal tunnel at 3- 6- and 12-month follow-up. The respective ratios [(CSA postoperatively/CSA preoperatively) × 100] were calculated and correlated with distal motor latency (DML) and sensory nerve conduction velocity (SCV).
  
  
  RESULTS
  The proximal CSA ratio was 88.9, 84.5, and 78.4 % at 3-, 6-, and 12-month follow-up, respectively. Each value was significantly lower than that before surgery. The distal CSA ratio was 104.3, 99.1, and 91.8 % at 3-, 6-, and 12-month follow-up, respectively. The values were not significantly different compared to preoperative values.
  
  
  CONCLUSIONS
  The proximal CSA of the median nerve decreased continuously over the time after CTR while the distal CSA increased up to 3 months before it decreased continuously, too.
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan. ainui@med.kobe-u.ac.jp.
authors.forename: Atsuyuki
authors.initials: A
authors.lastname: Inui
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Hanako
authors.initials: H
authors.lastname: Nishimoto
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Mifune
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kokubu
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Sakata
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002349:Carpal Tunnel Syndrome / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000000981:diagnostic imaging* / Q000601:surgery; D008875:Middle Aged; D009431:Neural Conduction; D012720:Severity of Illness Index; D014463:Ultrasonography
keywords: Carpal tunnel release; Carpal tunnel syndrome; Electrodiagnostic testing; Ultrasound