Influences of Repair Site Tension and Conduit Splinting on Peripheral Nerve Reconstruction

Abstract

Background We investigated the use of a conduit splinting technique to mitigate tension at the coaptation site of a rodent nerve defect model to determine the optimal reconstruction method for segmental nerve defects. Methods A rat sciatic nerve segmental defect model was created by excising 5mm of the sciatic nerve unilaterally. Four groups of 10 rats were each reconstructed using 1 of 4 techniques: primary repair, repair with conduit splinting, reverse isograft with conduit splinting, and reverse isograft without splinting. Functional outcomes were assessed at 6 weeks by measurement of Sciatic Functional Index (SFI), and sciatic nerves were harvested at the nonsurvival surgery. Histomorphologic measurements were reported as a value normalized to the average measurements of the control side. The primary outcomes were assessment of nerve continuity and the proportion of nerve fibers in the regenerating nerve compared with the uninjured side. Results The number of repair site rupture rates was lower when a conduit splint was used—less than half of the primary repairs under tension remained intact at 6 weeks. No difference was seen in axon number, size, and density between primary repairs and those augmented by conduit splints, but worse functional outcomes and more debris were present compared with the intact primary repairs. Conclusions Nerve conduit splinting reduced rupture rates, particularly for nerve repairs associated with a segmental defect. No significant difference was seen in the number of axons among techniques. Primary nerve repair under tension that did not rupture demonstrated superior SFI.

Efficacy of collagen conduit wrapping with collagen fibers on nerve regeneration in sciatic nerve injury with partial transection: An experimental study in the rat model

“…Nerve wrapping showed good results in animal models of crush injury and adhesion formation. [10][11][12] Furthermore, artificial nerve wraps (ANWs) yielded remarkable clinical results in recurrent/persistent carpal tunnel syndrome [13][14][15] and digital nerve injury. 16 In real-world clinical practice, we often experience partial nerve injuries with defects of several millimeters.…”

“…Hollow absorbable conduits are used for complete transection with short defects, while wrapping the injured part with absorbent material promotes nerve recovery by inhibiting inflammatory cell infiltration and scar tissue formation in crush injury. Nerve wrapping showed good results in animal models of crush injury and adhesion formation 10–12 . Furthermore, artificial nerve wraps (ANWs) yielded remarkable clinical results in recurrent/persistent carpal tunnel syndrome 13–15 and digital nerve injury 16 …”

End-to-side neurorrhaphy in the reconstruction of peripheral segmental neural loss: an experimental study

“…Strategies to reconstruct a segmental neural loss may include primary repair performed under excessive tension with restriction of joint movement; the use of hollow conduit to fill the gap; autologous nerve graft; allograft, end-to-end repair and neural transfer 7 .…”

“…The adverse influence of tension on nerve regeneration was initially observed by Duarte-Moreira et al 6 , and excessive tension at the repair site is directly proportional to the proliferation of fibrous tissue at the repair site, negatively influencing neural regeneration 4 . The use of conduits for segmental losses results in inferior results, but the use of conduits as an internal splint to relieve in-situ resting stress is promising 7 .…”

Reconstruction of Upper Extremity Peripheral Nerve Injuries Using an Epineurial-Like Collagen Device—A Prospective Clinical Study

“…4,[11][12][13] Conduit designs utilize methods inherited from historical nerve repairs which used bone and vein for rigidity and strength to protect the nerve from compression or tension forces during repair. 14 Many of these conduits are composed of polymers or reconstituted/natural collagen and are commonly fashioned into a hollow tube or cuff, which is placed around the coaptation site. [15][16][17][18][19] Processed acellular nerve allografts (PNA), similar to the hollow tube of collagen conduits, are biodegradable and have been tested for nerve repair.…”