A randomized clinical trial with 6-week follow-up compared the effects of night-only to full-time splint wear instructions on symptoms, function, and impairment in carpal tunnel syndrome (CTS). 17/21 patients (24/30 hands) completed the study. Thermoplastic, custom-molded, neutral wrist splints with subjects receiving either full-time or night-only wear instructions. 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. 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 = 0.004). The combined sample improved in three of four outcome measures: sensory distal latency (mean = 0.28 msec, standard deviation [SD] = 0.37, p = 0.004), symptom severity (mean = 0.64, SD = 0.46, p = 0.0001), and functional deficits (mean = 0.49, SD = 0.51, p = 0.0001). 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 (0.35 vs -0.07 msec, p = 0.04) and sensory (0.46 vs 0.13 msec, p = 0.05) when compared with subjects receiving night-only wear instructions.
Comment: The quality of evidence is downgraded by several limitations in study quality and by imprecise results (limited study size).