Tubulization techniques in brachial plexus surgery in an animal model for long-nerve defects (40 mm): a pilot study.

The critical length of 30 mm beyond which nerve regeneration was not possible limited up to now the use of tubulization. In this pilot study, a novel animal model is introduced using tubulization techniques for long-nerve defects (40 mm) in brachial plexus surgery. Twelve Sprague-Dawley rats were divided into 3 groups. A poly-DL-lactide-epsilon-caprolactone tube (group 1), a collagen tube (group 2), and a nerve graft (group 3) were, respectively, used to bridge a 40-mm gap between the right C7 root and the left musculocutaneous nerve. Animals were euthanized on day 30. Evaluation consisted of behavioral assessment, needle electromyography studies, biceps muscle weight measurements, qualitative, and quantitative morphometry. Only group 3 demonstrated axon regeneration and reinnervation potentials. There was statistical significant difference for biceps weight left/right ratio (P = 0.010) but not for behavioral results (P = 0.10) between group 3 and groups 1 and 2. This study introduced a novel rat model for the studying of nerve regeneration along long-nerve gaps (4 cm). Although using an autologous nerve graft regeneration achieved, the use of synthetic conduits failed to show regeneration. This may be attributed to gap length; duration of follow-up; and to no administration of a neurotrophic factor.