Regeneration and repair of peripheral nerves with different biomaterials: Review

Abstract

Peripheral nerve injury may cause gaps between the nerve stumps. Axonal proliferation in nerve conduits is limited to 10-15 mm. Most of the supportive research has been done on rat or mouse models which are different from humans. Herein we review autografts and biomaterials which are commonly used for nerve gap repair and their respective outcomes. Nerve autografting has been the first choice for repairing peripheral nerve gaps. However, it has been demonstrated experimentally that tissue engineered tubes can also permit lead to effective nerve repair over gaps longer than 4 cm repair that was previously thought to be restorable by means of nerve graft only. All of the discoveries in the nerve armamentarium are making their way into the clinic, where they are, showing great potential for improving both the extent and rate of functional recovery compared with alternative nerve guides.

Axonal Fusion via Conduit-Based Delivery of Hydrophilic Polymers

“…2 PEG solution therapy combined with nerve tubes demonstrates a statistically significant improvement in foot fault asymmetry score at weeks 1, 2, and 3 (p=0.007, p=0.01, and p=0.006 two-tailed t test). N=8 for PEG group and N=7 for control group Nerve tubes were selected for use in comparison to microsuture because collagen conduits have demonstrated improved regeneration when utilized to repair nerve gaps [9,12,23,26,30]. For the purposes of this study, we used a collagen tube to prevent microsuture placement at the site of nerve repair and as a conduit for delivery of solutions.…”

Primary repair of crush nerve injuries by means of biological tubulization with muscle‐vein‐combined grafts

“…1,4 Experimen-tal research on rat demonstrated that filling the veins with fresh muscle fibers allow to obtain nerve regeneration that similar to that observed with nerve autografting. 22,23 Muscle fibers avoid conduit's collapse and promote axo-nal regeneration and Schwann cell migration by means of basal lamina scaffolds.…”

“…1,5,13 Among the various biological and synthetic surgical tech-niques for nerve reconstruction, muscle-vein-combined conduits offer some important advantages: i) surgery was almost always performed in regional anesthesia allowing to harvest muscle tissue and veins, necessary for conduit preparation, from the same surgical field of nerve repair or just nearby to it; ii) however, donor sensory nerves, otherwise required to harvest a autograft for nerve repair, were preserved avoiding donor site morbidity 29 ; iii) the conduits were prepared according to reconstructive needs related to nerve size and defect length; iv) the costs for buying an artificial conduit were avoided. The latter point, however, deserves particular mention as, whereas autologous biological tissues clearly are appa-rently cost-free in comparison to artificial conduits on the market, their preparation requires additional operational room time.…”

“…[8][9][10][11] However, clinical outcome is often unsatisfactory and thus alternative types of nerve guides are sought. 1,5,12 The timing of intervention and the type of injury are major issues in nerve repair. As general rule, an open nerve injury should be early treated and repaired directly when optimal conditions, such as a) a clean-uncontami-nated wound and b) a sharp cut injury, are present.…”

Perspectives in regeneration and tissue engineering of peripheral nerves

“…Biological tubulization has received much attention over the last century and the best results have been obtained using veins and skeletal muscle tissue (Chiu and Strauch, 1990;Pereira et al, 1991;Geuna et al, 2004;Tos et al, 2007). Also the use of a non biological conduit for nerve repair (synthetic tubulization), a strat-egy that was first attempted by Payr already in 1900, has recently seen a tremendous development due to the potential commercial spin-off of biomaterials for clinical applications (Luis et al, 2007;Siemionow et al, 2010).…”