Reliability of provocative tests in determining the severity of carpal tunnel syndrome

Abstract

Background & Objectives: Electrodiagnostic study is the most frequently used diagnostic tool in confirming and grading carpal tunnel syndrome (CTS) severity. However, limited availability of electrodiagnostic tools in rural areas hinders its applicability in CTS diagnosis and grading. This study intends to seek the relationship between CTS provocative tests and the degree of CTS severity.

Methods: This is a cross-sectional study. Patients with symptoms of CTS were included in the study. Provocative tests (Tinel sign and Phalen’s test) were done in clinical setting followed by electroneurography in both hands of each patient. The Phalen test was performed with the wrist held in maximum passive flexion for 60 seconds, and the Tinel sign was elicited by tapping over the volar wrist crease. Both tests were considered positive if paresthesia or numbness in the median nerve distribution was reproduced. CTS diagnosis was confirmed by electroneurography (ENG) using standard nerve conduction criteria, and CTS severity was graded using Bland’s Neurophysiological grading scale. The relationship between provocative tests and CTS severity were analyzed using bivariate chi-square analysis.

Results: Forty-eight patients (87 hands) were included in this study. Most patients had bilateral CTS. Neurophysiological study confirmed 87 median nerve impingements, mostly of grade III. Positive provocative test (either Tinel/Phalen or both) was significantly related to CTS severity. The number of positive provocative tests according to CTS severity were as follows: 1/18 (5.6%) positive for one test in grade I, 14/17 (82.4%) positive for one test in grade II, 25/30 (83.3%) positive for one test and 5/30 (16.7%) positive for both tests in grade III, and 17/17 (100%) positive for both tests in grade IV and 5/5 (100%) in grade V.

Conclusions: Positive results of both provocative tests are consistent with more severe CTS.