The prevention of neuroma formation by diathermy: an experimental study in the rat common peroneal nerve.

INTRODUCTION There have been anecdotal reports of the efficacy of diathermy (electrocoagulation) in the prevention of neuroma formation. However, this has not been investigated in the laboratory. In this experiment involving 40 rats, diathermy was applied to the terminal proximal ends of transected rat common peroneal nerves to evaluate its effect on neuroma formation. MATERIALS AND METHODS Monopolar and bipolar diathermy set at 45 W, applied for different durations (4 seconds and 10 seconds), were evaluated. Under histological control, the presence of neuroma formation and the diameter of the nerve ends were evaluated at 3 months. The contralateral common peroneal nerve in the same rat served as the control. The dorsal root ganglia of 2 rats in each group were also harvested for histological study. RESULTS The incidence of neuroma formation was 30% in the group which received high-duration monopolar diathermy (10-second application), versus 90% in the control group (P <0.05). The mean diameter of the nerve ends was smaller at 0.51 mm [standard deviation (SD), 0.29] versus 0.85 mm (SD, 0.24) in the control (P <0.05). The incidence of neuroma formation was 30% in the group which received low-duration monopolar diathermy (4-second application), and 83% in the control group (P <0.05). The diameter was 0.43 mm (SD, 0.14) versus 0.85 mm (SD, 0.28) (P <0.05). High-duration bipolar diathermy applied for 10 seconds, showed a neuroma formation of 25% versus 100% in the control group (P <0.05). The diameter of the nerve ends was 0.48 mm (SD, 0.07) versus 0.79 mm (SD, 0.36) in the control group (P <0.05). The incidence of neuroma formation was 60% in the low-duration bipolar group, which received bipolar diathermy application for 4 seconds, and 90% in the control group (P = 0.25). The diameter of the nerve ends in the low-duration bipolar group was 0.52 mm (SD, 0.24) versus 0.76 mm (SD, 0.40). The incidence of neuroma formation and the difference in diameter in the low duration-bipolar group were both not statistically significant. CONCLUSION This study demonstrates the effectiveness of monopolar diathermy in reducing the rate of neuroma formation. For bipolar diathermy, an application of 10 seconds was effective in reducing neuroma formation but an application of 4 seconds was not associated with a significant reduction in neuroma formation.