Comparative efficacy of nerve coagulation vs. cap implantation in neuroma prevention using the rat sciatic nerve model: A histological and neuroradiological insight

INTRODUCTION: Peripheral nerve injuries pose a considerable challenge in reconstructive surgery due to the risk of neuroma formation, often resulting in severe pain and significant functional impairment. Various treatment modalities, including nerve coagulation and the use of nerve caps, have been explored to manage neuroma development. In this study, we compare the efficacy of chitosan and polylactide nerve caps to standard nerve coagulation in modulating neuroma morphology and promoting organized nerve regeneration. METHODS: Female Sprague Dawley rats (n = 40) were divided into four equal groups: Sham (control), Coagulation, Polylactide Cap (Neurocap®), and Chitosan Cap. After neurotmesis of the sciatic nerve, the respective treatments were applied. The evaluation period spanned 12 weeks, with MR neurography performed at 6 and 12 weeks. Histological analyses of the harvested tissue were performed at 12 weeks. A survey among 16 plastic and nerve surgeons assessing neuroma formation and scarring was conducted. RESULTS: On macroscopic evaluation, the Chitosan (C) and Polylactide (P) Cap groups displayed denser, more contained neuromas, while the Sham (S) and Coagulation (K) groups exhibited irregularly shaped neuromas with peripheral extensions. Histomorphometry showed higher axon density [ρ(C) = 15851 ± 7132 axons/mm², ρ(P) = 15657 ± 4066 axons/mm²] and thicker myelin sheaths [thm(C) = 0.808 ± 0.054 µm, thm(P) = 0.786 ± 0.045 µm] in the cap-treated groups compared to Sham [ρ(S) = 8052 ± 5080 axons/mm², thm(S) = 0.704 ± 0.060 µm; p(C/S) = 0.0193, p(P/S) = 0.0029 for axon density, p(C/S) = 0.0019, p(P/S) = 0.0046 for myelin thickness], but with no significant differences compared to the Coagulation group [ρ(K) = 14023 ± 7383 axons/mm², thm(K) = 0.745 ± 0.075 µm, p > 0.05]. Surgeon survey findings aligned with macroscopic evaluations, indicating consistency in neuroma shape classification. CONCLUSION: Chitosan and polylactide nerve caps effectively promote organized nerve regeneration and prevent disorganized neuroma formation. Nerve coagulation demonstrated comparable efficacy in certain parameters, suggesting it could remain a viable treatment option. These findings provide valuable insights for optimizing surgical approaches to peripheral nerve injuries, paving the way for more personalized and effective therapeutic strategies.