Contralateral botulinum toxin improved functional recovery after tibial nerve repair in rats

Background: There is clinical and experimental evidence that botulinum toxin applied to the healthy side of patients with facial paralysis positively affects functional recovery of the paralyzed side. We created an experimental model to study the effects of botulinum toxin injection in the gastrocnemius muscle contralateral to the side of tibial nerve lesion/repair in rats. Methods: Fifty rats were allocated into five groups: I: control; II: tibial nerve section; III: tibial nerve section, immediate neurorrhaphy; IV: tibial nerve section, immediate neurorrhaphy and botulinum toxin injected into the contralateral gastrocnemius muscle; V: botulinum toxin injected into the gastrocnemius muscle, no surgery. Assessment tools included a walking track, electromyography, gastrocnemius muscle weight measurement, and histological analysis of the nerve. Results: Paralysis in group V was transient, with function returning to normal at 8 weeks. At 12 weeks, group V had lower latency levels. At week 12, group IV showed higher functional outcomes and amplitude levels than group III, and lower muscle atrophy on the side injected with botulinum toxin than group V. Conclusions: Transient paralysis of the contralateral gastrocnemius muscle by abobotulinumtoxinA improved functional recovery in rats that underwent section and repair of the tibial nerve. Presented at: American Society for Peripheral Nerve Annual Meeting (ASPN) 2017 in Waikoloa, Hawaii. Financial Disclosure Statement: The authors have no financial interest in any of the products, devices, or drugs mentioned in this manuscript. Corresponding author: Alessandra Grassi Salles, Rua Joaquim Floriano, 466, cj. 2102, São Paulo 04534-002, Brazil. Tel/Fax: 55-11-3078-1009, E-mail: agsalles30@gmail.com ©2018American Society of Plastic Surgeons