[Model of "bridge" graft between the cervical spinal cord and biceps muscle using a peripheral nerve autograft. Study...

The authors present, in the adult rat, a model of reconnection between an injured cervical spinal cord (C5) and the biceps brachii muscle (BB) previously denervated, by means of an autologous peripheral nerve segment (PNG). The study includes 30 rats shared into 4 principal groups: A) the denervation of BB by transection and ligature of the musculocutaneous nerve (MCN); B) transection and immediate suture of the MCN; C) transection/ligature of the MCN and insertion of a PNG both into the cervical spinal cord and into the BB; D) transection of the MCN, ligature of its proximal tip, insertion of one end of a PNG into the cervical spinal cord and suture of the other end with the distal stump of the MCN. Assessment of the following parameters were performed, in all animals, three months after the grafting procedure: 1) the muscle strength by using the toilet test; 2) the weight of the experimental BB in comparison to the contralateral BB; 3) the response (contraction) of the BB under electrical stimulation of either the MCN or the PNG; 4) the histological appearance of the BB; 5) the presence of retrogradely labelled neuronal somata in the cervical spinal cord following application of horseradish peroxidase (HRP) to the MCN or to the GNP. These parameters of evaluation have at first been validated in two cases already known: the chronic denervation of the BB (group A), and the peripheral nerve lesion (group B). Once these cases validated, they have been used to appreciate the muscular reinnervation by axonal growth from the spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)