Superficial or deep implantation of motor nerve after denervation: An experimental study—superficial or deep implantation of motor nerve

Abstract

Neurorraphy, conventional nerve grafting technique, and artificial nerve conduits are not enough for repair in severe injuries of peripheral nerves, especially when there is separation of motor nerve from muscle tissue. In these nerve injuries, reinnervation is indicated for neurotization. The distal end of a peripheral nerve is divided into fascicles and implanted into the aneural zone of target muscle tissue. It is not known how deeply fascicles should be implanted into muscle tissue. A comparative study of superficial and deep implantation of separated motor nerve into muscle tissue is presented in the gastrocnemius muscle of rabbits. In this experimental study, 30 white New Zealand rabbits were used and divided into 3 groups of 10 rabbits each. In the first group (controls, group I), only surgical exposure of the gastrocnemius muscle and motor nerve (tibial nerve) was done without any injury to nerves. In the superficial implantation group (group II), tibial nerves were separated and divided into their own fascicles. These fascicles were implanted superficially into the lateral head of gastrocnemius muscle-aneural zone. In the deep implantation group (group III), the tibial nerves were separated and divided into their own fascicles. These fascicles were implanted around the center of the muscle mass, into the lateral head of the gastrocnemius muscle-aneural zone. Six months later, histopathological changes and functional recovery of the gastrocnemius muscle were investigated. Both experimental groups had less muscular weight than in the control group. It was found that functional recovery was achieved in both experimental groups, and was better in the superficial implantation group than the deep implantation group. EMG recordings revealed that polyphasic and late potentials were frequently seen in both experimental groups. Degeneration and regeneration of myofibrils were observed in both experimental groups. New motor end-plates were formed in a scattered manner in both experimental groups. However, they were more dense in the superficial implantation group than the deep implantation group. It was concluded that superficial implantation has a more powerful contractile capacity than that of deep implantation. We believe that this might arise from the high activity of glycolytic enzymes in peripheral muscle fibers of gastrocnemius muscle, decrease in insufficient intramuscular guidance apparatus, and intramuscular microneuroma formation at the insufficient neuromuscular junction since the motor nerve had less route to muscle fibers.

Relevance of Muscle Weight as a Functional Parameter for the Regeneration of the Peroneal Nerve in Rabbits

“…For each operation, the rabbits received premedication with ketamine 65 mg/kg body weight and xylazine 4 mg/ kg subcutaneously before oral intubation (xylazine, as an a 2 -receptor agonist with a general sedative-hypnotic effect, leads to temporary muscle relaxation for 30 to 60 minutes). 11 Anesthesia was maintained with isoflurane, O 2 , and N 2 O under spontaneous breathing. The peroneal nerves were exposed through a muscle-sparing incision along the sciatic vein.…”

Successful intramuscular neurotization is dependent on the denervation period. A histomorphological study of the gracilis muscle in rats

“…This procedure was clinically refined by several groups 2, 4, 14. The distal end of each graft segment is microsurgically dissected to separate the fascicles in a proximal direction, thus creating neural branching, and then each fascicle is inserted into the denervated muscle.…”

Reparo do nervo facial com sutura epineural térmico-terminal e coaptação com adesivo de fibrina em ratos associado ou não a laserterapia

“…enxerto arterial e venoso (FAWCETT; KEYNES, 1990;ROQUE, 2008;ROSA JUNIOR, 2013), enxerto de segmento nervoso periférico PARVIN, 1994;WATCHMAKER;MACKINNON, 1997;LUNDBORG, 2000;ASKAR;SABUNCUOGLU, 2002), tubos de silicone e de polietileno, (LI et al, 2010;HISASUE et al, 2005), tubos de pericárdio bovino (AHMED et al, 2005) AQUINO; OLIVEIRA, 2013).…”