Acute median nerve dysfunction from wheelchair propulsion: the development of a model and study of the effect of hand protection.

Abstract

Carpal tunnel syndrome is prevalent among individuals who are wheelchair dependent. Maximal electrophysiologic median nerve dysfunction has been isolated to the proximal part of the carpal tunnel--the site of hand-wheel interface during wheeling. The objective of this study was to determine if measurable median nerve dysfunction (conduction slowing or block) results from a single session of vigorous wheeling and, if so, if protection for the hand with a glove (padded over the region of the carpal tunnel) could minimize the dysfunction. Thirty-five subjects (16 wheelchair dependent; 19 able-bodied) propelled a roller-mounted wheelchair at maximal rate of 2,000 hand strikes. A protective glove was worn on 1 hand only. Immediately before and after the wheeling, hand surface temperatures and bilateral median motor and sensory conductions were performed, and across-carpal tunnel conduction velocity and conduction block were calculated. Another group of 11 able-bodied subjects underwent similar electrodiagnostic testing before and after one half hour of vigorous stationary cycling (no hand trauma). Results were analyzed using a three-way analysis of covariance for repeated measures and demonstrated that (1) significant increases (5.2% to 8.5%) in across carpal tunnel conduction block occurred as a result of wheelchair propulsion but not cycling; (2) the wheeling-induced conduction block was not altered by using a protective glove. This study has demonstrated a model for measuring acute median nerve dysfunction resultant from wheeling but raises doubts regarding the protective effect of glove use on median nerve function.