title: Does the ulnar nerve enlarge after surgical transposition?
abstract: OBJECTIVE
  The purpose of this study was to test the hypothesis that symptomatic transposed ulnar nerves have a larger average cross-sectional area (CSA) than symptomatic in situ ulnar nerves.
  
  
  METHODS
  We conducted a retrospective review of the charts and sonograms of 68 patients who had failed ulnar nerve transposition compared to 48 patients with cubital tunnel syndrome who had not undergone surgical management. In addition, postoperative sonograms were compared with preoperative studies when available. Failure was defined as persistence or recurrence of symptoms of ulnar neuropathy postoperatively. The cross-sectional area of the nerve, subjective echogenicity, and residual sites of compression were recorded. Groups were subsequently compared by t tests.
  
  
  RESULTS
  The failed ulnar nerve transposition group showed a mean cross-sectional area ± SD of 17.26 ± 9.93 mm(2), whereas the control group showed a mean cross-sectional area of 13.45 ± 7.33 mm(2). This difference was statistically significant (P= .018). Nontransposed nerves were more likely to have identifiable sites of compression (P< .05). There was a trend toward postoperative enlargement in the 6 patients with available preoperative imaging (P = .17). No difference in subjective echogenicity was found in this analysis.
  
  
  CONCLUSIONS
  Patients with failed ulnar nerve transposition show a significantly enlarged cross-sectional area when compared to symptomatic nerves in situ. Although a specific etiology for this difference cannot be determined, the data suggest that the reference ranges for the cross-sectional area of the ulnar nerve may need to be revised for those who have undergone surgery.
authors.affiliation: Departments of Orthopedic Surgery (M.M.V., T.D.T., A.M.I.) and Diagnostic Radiology (L.N.N.), Thomas Jefferson University Hospital, Philadelphia, Pennsylvania USA. michael.vosbikian@gmail.com.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Vosbikian
authors.affiliation: Departments of Orthopedic Surgery (M.M.V., T.D.T., A.M.I.) and Diagnostic Radiology (L.N.N.), Thomas Jefferson University Hospital, Philadelphia, Pennsylvania USA.
authors.forename: T David
authors.initials: TD
authors.lastname: Tarity
authors.affiliation: Departments of Orthopedic Surgery (M.M.V., T.D.T., A.M.I.) and Diagnostic Radiology (L.N.N.), Thomas Jefferson University Hospital, Philadelphia, Pennsylvania USA.
authors.forename: Levon N
authors.initials: LN
authors.lastname: Nazarian
authors.affiliation: Departments of Orthopedic Surgery (M.M.V., T.D.T., A.M.I.) and Diagnostic Radiology (L.N.N.), Thomas Jefferson University Hospital, Philadelphia, Pennsylvania USA.
authors.forename: Asif M
authors.initials: AM
authors.lastname: Ilyas
mesh_terms: D000328:Adult; D000368:Aged; D001837:Body Weights and Measures / Q000379:methods*; D020430:Cubital Tunnel Syndrome / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014459:Ulnar Nerve / Q000000981:diagnostic imaging* / Q000601:surgery*; D014463:Ultrasonography; D055815:Young Adult
keywords: cross-sectional area; cubital tunnel syndrome; failed ulnar nerve transposition; musculoskeletal ultrasound; sonography; ulnar neuropathy