Upper Extremity Disability Is Associated With Grip Strength and Psychological Stress in Carpal Tunnel Syndrome According to a Patient-reported Questionnaire

Abstract

Objective: We investigated which clinical factors influenced upper extremity disability in carpal tunnel syndrome (CTS). Materials and Methods: We analyzed 45 hands with CTS of patients enrolled in a prospective cohort study conducted from December 2012 to January 2015. The age among the participant group of 40 females and 5 males ranged from 30 to 86 (mean, 60.3 years). Forty-three patients were right-handed. Twenty-seven had bilateral CTS (36 hands). Operations were performed on 25 right and 20 left hands. Thirty-nine hands were classified as “Extreme CTS” (absence of median motor and sensory responses) according to the severity scale proposed by Padua. Hand10 was used as a validated upper-extremity disability assessment tool. Clinical assessments were comprised of patients’ characteristic, physical and psychological parameters. Patients’ characteristic consisted of age, body mass index, and duration of symptom. Physical parameters included grip strength, key pinch strength, pulp pinch strength, Semmes Weinstein Monofilament Test, static 2 point discrimination test (s2PD test), numerical rating scale for numbness, visual analogue scale for pain (pain VAS), and Japanese version of Short-Form McGill Pain Questionnaire (SF-MPQ). Psychological parameters included Japanese version of Self-rating Depression Scale, Japanese version of Pain Anxiety Symptom Scale–20 (PASS-20), and Stress Response Scale–18 (SRS-18). These assessments were conducted on the day before operation. Statistical Analysis: Factors that were significantly associated with Hand10 scores in bivariate analysis (Pearson correlation test or Spearman rank correlation test as appropriate) were entered into a multivariable analysis. A multiple regression analysis was used to identify factors that were independently associated with Hand10 scores. Results: Hand10 scores showed no statistical differences in terms of unilateral/bilateral CTS and sex differences. Single regression analysis showed that Hand10 scores correlated significantly with the pain VAS, SF-MPQ, PASS-20, SRS-18, s2PD at index and middle scores, and grip strength. Multiple regression analysis showed that grip strength ( B = 1.47, β = 0.49, P = .00) and SRS-18 score ( B = −0.91, β = −0.36, P = .02) were significant correlation factors for the Hand10 score ( R2 = 0.49). Conclusions: In patients with CTS, grip strength and psychological stress are significant correlating factors of disability according to a patient-administered upper extremity assessment.