No abstract

Nerve conduits and acellular nerve allograft offer efficient and convenient tools for overcoming unexpected gaps during nerve repair. Both techniques offer guidance for migrating Schwann cells and axonal regeneration though utilizing very different scaffolds. The substantially greater amount of animal and clinical data published on nerve conduits is marked by wide discrepancies in results that may be partly explained by a still poorly defined critical repair gap and diameter size. The available information on acellular allografts appears more consistently positive though this tool is also hampered by a longer but also limited critical length. This article reviews the current relative literature and examines pertinent parameters for application of both acellular allograft and nerve conduits in overcoming short nerve gaps.

The authors describe a reverse end-to-side neurorrhaphy model in which the proximal end of a donor nerve is sutured to an epineurial window in the side of a recipient nerve. If effective, this technique would have useful applications in nerve reconstructive surgery. Female Sprague-Dawley rats were divided into three groups (n = 9). In Group A, the peroneal nerve was transected and directly repaired in standard end-to-end fashion. In Group B, the tibial nerve was transected and the proximal end was sutured to the side of the intact peroneal nerve through an epineurial window. In Group C, the tibial nerve was also transected and the proximal end sutured to the side of the intact peroneal nerve, but the peroneal nerve was then cut proximally. After 12 weeks, contractile forces of the extensor digitorum communis (EDC) were measured, following stimulation of the proximal sciatic nerve on all experimental (and normal) hind limbs. For Group B, the peroneal nerve was transected proximal to the repair site just prior to stimulation. Group B animals did not demonstrate any measurable contractions. No statistically significant differences were found between Groups A and C. This demonstrated the successful neurotization of a denervated muscle using a reverse end-to-side neurorrhaphy model.

No abstract

Bypass grafting around a neuroma-in-continuity entails coapting a nerve graft above and below the injured segment using two sequential end-to-side repairs. The proximal repair is analogous to what has been classically described as an end-to-side repair; the axons from the intact nerve sprout into the end of a recipient nerve and travel distally. At the distal connection, however, axons in the graft must enter the side of the intact nerve and find their way to appropriate end organs. This process has not been well investigated. To examine this, a reverse end-to-side repair, suturing the distal end of the peroneal nerve to the side of a transected and repaired tibial nerve, was performed in 20 rats. A primary end-to-end repair of the tibial nerve was performed in 10 additional rats. Twelve weeks later, contraction forces of the gastrocnemius muscle were measured following proximal stimulation. Measurements were repeated following elimination of potential axonal pathways to identify which axons (peroneal or tibial) had achieved greater reinnervation. The results indicated that both groups of axons had achieved significant reinnervation. This study supports the idea that a reverse end-to-side repair can result in axonal invasion of an intact but regenerating nerve and achieve functional recovery.