Side to Side Supercharging Allograft
Technical Report,30 Sep 2016,29 Sep 2017
Virginia Commonwealth University Richmond United States
Pagination or Media Count:
Processed a cellular nerve allograft PNA is becoming an increasingly popular modality for addressing segmental nerve defects during nerve repair. Side-to-side grafting between the PNA and regional in situ nerve trunks may be able to increase the effective critical length of the PNA. Nerve tissue loss and retraction can result in segmental gaps requiring some form of grafting. Autologous nerve grafting is associated with potential donor morbidity, added surgical time, and increased surgical effort. In some circumstances, such as may be seen in military level traumas, there is insufficient nerve autograft material available due to the complex multiextremity involvement. Processed Acellular Nerve Allograft PNA maintains some guidance cues and provides an effective scaffolding system but depends on in situ Schwann cell migration to support axon regeneration. Though this process appears reliable over short and medium nerve defects, with increasing graft lengths, Schwann cells regress from a neuro supportive phenotype to an inactive or senescent state in which proliferation, apoptosis, and normal function are all impaired. A similar process occurs in chronically denervated nerve in which Schwann cell numbers are decreased and regeneration-associated genes are down regulated. Recently, several small animal studies demonstrated that donor axons introduced into the side of a long autograft or chronically denervated nerve stump by reverse end-to-side nerve repair or supercharging enhanced axon regeneration and recovery. In a variation of this strategy, donor axons provided by side-to-side bridge grafts placed between an intact rodent tibial nerve and the chronically denervated distal peroneal stump like rungs on a ladder improved muscle weight, axon numbers, and myelination implicating the Schwann cells following delayed repair.
- Medicine and Medical Research