The Utility of Diagnostic Tests for Digital Nerve Injury.

Purpose: The purpose of this study was to present the sensitivity and specificity of 6 clinical tests for the diagnosis of digital nerve injury. The clinical tests are as follows: light touch, pinprick, static and dynamic 2-point discrimination (D2PD), Semmes-Weinstein monofilament, and wrinkle test.

Methods: We reviewed the charts of all the patients who were admitted to our department with hand lacerations and/or suspicions of digital nerve injury that were examined before surgery with the 6-sensation test, comparing the results to the surgical findings.

Results: The study included 70 patients with 85 injured nerves overall. Of the 85 nerves, 51 were found with full cut, 9 with partial cut, and 25 with no cut. Only 2 variables were significantly associated with the study outcome: D2PD > 4 (P = 0.0141, odds ratio = 3.9, 95% confidence interval = 1.3-11.8, sensitivity = 80.7%, specificity = 48%) and wrinkle test (P = 0.0098, odds ratio = 4.0, 95% confidence interval = 1.4-11.6, sensitivity = 69.5%, specificity = 62.5%).Multivariable logistic regression included these variables and revealed the predictive probability for a nerve injury to be 92% if both risk factors exist and 43% if none of these risk factors exist. If one risk factor exists, the predictive probability for a cut is still very high (75%).

Conclusions: The combination of positive wrinkle test and D2PD > 4 gave a predictive probability for a nerve injury as 92% in the cases in our study and should be considered in the evaluation of patients with hand lacerations and suspicions of digital nerve injury.