ABSTRACT
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.
Neuroma formation in extremity amputations, particularly finger amputations, can be extremely disabling. There have been many methods advocated for the prevention and management of such amputation neuromas,1-29 but no one method has been shown to be ideal. The most popular and simplest method, peripheral neurectomy, involves the proximal section of the nerve in such a way that the neuroma is situated in a well-vascularised and padded area.1 Unfortunately, the digit has a paucity of soft tissue, and digital neuromas may adhere to scar tissue or bone and cause severe pain. Other methods include epineurial ligation, microsurgical funicular closure, silicone capping, transposition, microneural anastomoses, chemicals (phenol, alcohol, steroids, ricin, nitrogen mustard), and radioactivity. The disadvantages of these various methods include poor results,12 high costs, toxicity, need for microsurgical skill, prolonged surgery, excessive dissection, and additional logistical requirements. Although there has been a plethora of reports on the different methods of preventing or treating amputation neuromas, there has been no published journal article in the English language on the use of diathermy. Anecdotal experience in our practice has suggested that the application of diathermy to transected nerve ends in finger amputations were not associated with symptomatic neuromas. In addition, a case report reported the use of thermocautery as a useful method in the prevention of traumatic neuroma of the great auricular nerve during parotid surgery.30 A German paper published in the 1950s briefly reported anecdotal experience on the use of percutaneous electrocoagulation as a method of performing proximal neurectomies for the management of symptomatic amputation stump neuromas.31 Hence, the aim of this study was to examine the incidence of neuroma formation following diathermy of scalpel-transected nerve ends of the common peroneal nerve (CPN) in rats.
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