IngentaConnect Variation in nerve autograft length increases fibre misdirection ...

Abstract:

Objectives: In the clinical set, autologus nerve grafts are the current option for reconstruction of nerve tissue losses. The length of the nerve graft has been suggested to affect outcomes. Experiments were performed in the rat in order to test this assumption and to detect a possible mechanism to explain differences in recovery.

Methods: The rat median nerve was repaired by ulnar nerve grafts of different lengths. Rats were evaluated for 12 months by behavioural assessment and histological studies, including ATPase myofibrillary histochemistry and retrograde neuronal labelling.

Results: It was demonstrated that graft length interferes in behavioural functional recovery that here correlates to muscle weight recovery. Short nerve grafts recovered faster and better. Reinnervation was not specific either at the trunk level or in the muscle itself. The normal mosaic pattern of Type I muscle fibres was never restored and their number remained largely augmented. An increment in the number of motor fibres was observed after the nerve grafting in a predominantly sensory branch in all groups. This increment was more pronounced in the long graft group. In the postoperative period, about a 20% reduction in the number of misdirected motor fibres occurred in the short nerve graft group only.

Conclusion: Variation in the length of nerve grafts interferes in behavioural recovery and increases motor fibres misdirection. Early recovery onset was related to a better outcome, which occurs in the short graft group.

Keywords: BRACHIAL PLEXUS; MUSCLE REINNERVATION; NERVE GRAFTS; NERVE REPAIR; NERVE REGENERATION

Document Type: Research article

DOI: 10.1179/016164105X18494

Affiliations: 1: Universidade do Sul de Santa Catarina - Unisul, Centro de Ciências Biológicas e da Saúde- CCBS, Tubaraão, SC, Brazil; Governador Celso Ramos Hospital, Department of Orthopedic Surgery, Hand and Microsurgery Group. Praça Getulio Vargas, 322, Florianópolis, SC, 88020030, Brazil 2: Laboratoire de Neurobiologie, CNRS-URA 1448, Groupe 'Régenération des Nerfs Périphériques et des Muscles Squeléttiques', Universite René Descartes, 45 rue des Saints-Péres, 75006 Paris, France 3: Universidade do Sul de Santa Catarina - Unisul, Centro de Ciências Biológicas e da Saúde- CCBS, Tubaraão, SC, Brazil

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Variation in nerve autograft length increases fibre misdirection and decreases pruning effectiveness. An experimental study in the rat median nerve