Objective: To compare the effects of night-only to full-time splint wear instructions on symptoms, function, and impairment in carpal tunnel syndrome (CTS).
Design: Randomized clinical trial with 6-week follow-up.
Setting: Veterans Administration Medical Center, outpatient clinic.
Subjects: Outpatients with untreated CTS were consecutively recruited from our electrodiagnostics lab. Twenty-one patients (30 hands) were enrolled, and 17 patients (24 hands) completed the study.
Interventions: Thermoplastic, custom-molded, neutral wrist splints with subjects receiving either full-time or night-only wear instructions.
Outcome measures: Symptoms and functional deficits were measured by Levine's self-administered questionnaire, and physiologic impairment was measured by median nerve sensory and motor distal latency. COMPLIANCE AND CROSSOVER: Almost all (92%) of the combined sample reported frequent splint use, but their adherence to specific wearing instructions was limited. A majority (73%) of the full-time group reported splint wear less than one half of waking hours, and some (23%) of the night-only group reported occasional daytime wear. Despite this tendency for treatment crossover, the two treatment groups differed in daytime wear as intended (chi2 analysis, p = .004).
Results: The combined sample improved in three of four outcome measures: sensory distal latency (mean = .28msec, standard deviation [SD] = .37, p = .004), symptom severity (mean = .64, SD = .46, p = .0001), and functional deficits (mean = .49, SD = .51, p = .0001). Severity of CTS was a factor only in sensory distal latency improvement (more improvement in severe CTS). Subjects receiving full-time wear instructions showed superior distal latency improvement, both motor (.35 vs -.07msec, p = .04) and sensory (.46 vs . 13msec, p = .05) when compared with subjects receiving night-only wear instructions.
Conclusions: This study provides added scientific evidence to support the efficacy of neutral wrist splints in CTS and suggests that physiologic improvement is best with full-time splint wear instructions.