Improving hand sensibility in vibration induced neuropathy: A case-series

We report a long-term series of nine workers suffering from vibration-induced neuropathy, after many years of exposure to hand-held vibrating tools at high or low frequency. They were treated with temporary selective cutaneous anaesthesia (EMLA® cream) of the forearm repeatedly for a period up to one year (in two cases four years). The aim was to improve their capacity to perceive touch and thereby improve hand function and diminish disability. The treatment principle is based on current concepts of brain plasticity, where a deafferentation of a skin area results in improved sensory function in adjacent skin areas.

All participants had sensory hand problems in terms of numbness (median touch thresholds > 70 mg) and impaired hand function influencing ADL (mean DASH score 22).After an initial identical self-administered treatment period of 8 weeks (12-15 treatments with increasing intervals) they did one treatment every 2-3 month.

After one year sensibility (touch thresholds and tactile discrimination) as well as hand function (mean DASH score 13) were improved in a majority of the cases. Seven of the participants choose to continue the treatment after the first year and two of them have continued at a regular basis for up to four years. A surprising, secondary finding was diminishing nocturnal numbness of the hand and arm in eight of the nine subjects from "frequently" to "hardly ever or never".

Our observations open new perspectives for treatment of impaired sensibility and hand function in a group of patients with vibration induced hand problems where we have no treatment to offer today.