Subclinical injury to forearm nerves during radial harvesting: electrophysiologic study

There are few reports about injury to forearm nerves and its potential mechanisms during radial artery (RA) harvesting. We studied electrophysiologic changes in these nerves not sought until now.

Among 152 consecutive patients who underwent coronary artery bypass surgery between February 2002 and August 2002, 20 were randomized for RA harvesting and formed the study group and 20 were randomized as control group. Neurologic examination and electrophysiologic studies were performed for sensory and motor impairment of the nerves in both groups pre- and postoperatively.

There was no change on neurologic examinations before and after surgery. Electromyography (EMG) revealed significant reduction in sensory and motor conduction amplitudes of median, ulnar, and radial nerves and motor conduction velocities of median and ulnar nerves at the level of forearm in the study group. In the control group, ulnar nerve was mostly affected. When two groups are compared, sensory and motor amplitude drops of median and radial nerves and motor velocity impairment of median nerve in the study group are significant. Ulnar nerve impairments are identical in both groups.

Handling of tissues, minor hematoma or edema along with chest retraction best explains these impairments. Patients were asymptomatic after surgery showing that EMG is highly sensitive and is not predictive of clinical impairment.