Sensory deficits after a radial nerve injury.

Background: The aim of our study was to objectively test sensibility on the dorsal side of the hand in patients with radial nerve injury, to document deficits and to detect if surgery for sensory reconstruction is needed.

Methods: Nineteen patients of mean age 31 ± 10 years were examined at a mean of 26.4 ± 27.8 months post radial nerve injury. Sensory mechanical thresholds on the dorsal surface of the hand were evaluated using Semmes-Weinstein monofilaments. Sensation was considered significantly impaired when there was no perception of a 2.0 gr. Semmes-Weinstein filament. Nociception was evaluated using Adson forceps.

Results: Five patients had normal 2.0 monofilament perception. Two of these five also had normal perception of the lighter 0.05 monofilament. In nine patients, zones of impaired sensibility were restricted to the first web space. In combined radial and musculocutaneous nerve lesions, the zone of impaired sensibility extended to the dorsum of the third metacarpus and occasionally to the dorsal aspect of the thumb. This zone averaged being five times the size as in isolated radial nerve injuries. On average, the zone of decreased 0.05 monofilament perception was six times the size detected for the 2.0 monofilament. No patient had complete anesthesia over the dorsum of the hand. No patient complained about pain or numbness. Only one patient among four with a combined radial and musculocutaneous nerve injury required sensory reconstruction.

Conclusions: Minimal sensory abnormalities should be expected after a radial nerve injury. Patients likely neither warrant nor request sensory reconstruction.