THE EFFECT OF BIPOLAR ELECTROCAUTERY ON PERIPHERAL-NERVES

Although bipolar cautery was designed to minimize trauma to the centra l nervous system, little is known about the effects of bipolar cautery on peripheral nerve tissue. This experiment was designed to study the effect of direct bipolar cautery on a peripheral nerve and the muscle s innervated by that nerve. Lewis rats (n = 200) were assigned to five different groups: control, sham, and three cautery groups (duration o f either 0.5, 1.0, or 1.5 seconds). The hind limb tibial nerves were i solated in the sham group and isolated and cauterized in the cautery g roups. Assessments performed at 2 hours, 2 weeks, 4 weeks, and 8 weeks postoperatively included isometric contractile function studies of bo th a fast-and a slow twitch muscle, muscle weights, and nerve histolog y/morphometry. Significant muscle weight loss and reduced muscle funct ion were found in the cautery groups at 2, 4, and 8 weeks (p < 0.05). Histologically, the nerves of the cautery groups showed nerve damage c onsistent with Sunderland's type 4 nerve injury when examined at 2 wee ks and showed nerve regeneration at 4 and 8 weeks. Both the fast-twitc h muscle and the shorter duration cautery were associated with faster recovery relative to the slow-twitch muscles and longer duration caute ry, respectively. Bipolar cautery, as administered to rat tibial nerve s in this experiment, is associated with a significant injury to the n erve and loss of function of the muscles innervated by the nerve.