title: Baseline Characteristics of the Median Nerve on Ultrasound Examination.
abstract: Background:Previous studies using ultrasound for diagnosis of carpal tunnel syndrome have reported on relatively small series of patients, leading to large standard deviations and/or confidence intervals for the mean cross-sectional area of the median nerve. The purpose of this study is to define the CSA of the median nerve in a large cohort of patients.Methods:Patients (n = 175) without history of carpal tunnel release were recruited. All participants were evaluated using the Carpal Tunnel Syndrome-6 questionnaire, a validated clinical diagnostic tool, with a score of 12 or greater considered positive for CTS. Ultrasound examination was performed on both wrists of all participants using a 13-6 MHz linear array transducer.Results:The mean median nerve CSA was significantly larger (P < .001) for patients with a positive (mean = 11.16, SD = 2.51) versus negative CTS-6 result (mean = 6.91, SD = 2.06). There was a significant correlation (.527, P < .001, n = 349) between CSA and CTS-6 score. Logistic regression analysis determined that a CSA of 10 mm2 optimized sensitivity and specificity at 80% and 88%, respectively. Accuracy was 87.9%.Conclusions:A significant difference in mean CSA was found between patients with and without CTS. Median nerve CSA showed a statistically significant positive correlation with CTS-6. Similar to prior studies, a CSA of 10 mm2 was determined to be the optimal cutoff. In this large series of patients, ultrasound was a sensitive, specific, and accurate test for confirmation of a clinical diagnosis of CTS.
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Tiffany J
authors.initials: TJ
authors.lastname: Pan
authors.affiliation: Hand & UpperEx Center, Wexford, PA, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: White
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Caiyan
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Hand & UpperEx Center, Wexford, PA, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Hagberg
authors.affiliation: Hand & UpperEx Center, Wexford, PA, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Imbriglia
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Fowler
mesh_terms: D002349:Carpal Tunnel Syndrome / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008875:Middle Aged; D012015:Reference Standards; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D014953:Wrist
keywords: carpal tunnel syndrome; diagnosis; median nerve; sonography; ultrasound