Page 10 - Read Online

Buncke. Plast Aesthet Res 2022;9:38 https://dx.doi.org/10.20517/2347-9264.2022.08 Page 5 of 17

Figure 3. Peripheral nerve repair algorithm.

Off-the-shelf options for bridging nerve gaps include extracellular matrix scaffolds that support axonal
regeneration, cellular and non-cellular graft additives. Ideally, a nerve scaffold should: be readily available,
be biodegradable over a time appropriate for the application, be able to be revascularized, support cell
migration, elicit a limited immunogenic response, allow for oxygen and nutrient diffusion, be adjustable for
the nerve injury severity, not lead to long-term nerve compression, and support nerve regeneration [19-21] .
Furthermore, Porzionato et al. proposed that the best scaffold for tissue engineering is decellularized
[22]
extracellular matrix of the same origin as the target tissue . Scaffolds that support axonal regeneration can
be engineered from natural or synthetic materials, although natural materials are thought to show improved
biocompatibility, decreased toxicity, and better cellular migration . The addition of bioactive factors and
[19]
cells have also been investigated with the use of nerve scaffolds to stimulate cell migration and provide a
preferential substrate for axonal migration . While many of these advancements are not yet clinically
[19]
available, novel materials for peripheral nerve repair such as engineered nerve allografts and nerve conduits
are currently clinically available. The clinical emergence of these materials has inevitably changed the
landscape of peripheral nerve repair and the surgical algorithm. This manuscript will explore the advent of
nerve conduits and engineered peripheral nerve allografts and how their use has impacted the repair of
transected peripheral nerves over time. Furthermore, this manuscript will focus on the clinical application
of these technological advancements in extremities, as the most frequently injured nerves are located in the
extremities.

HISTORY OF PERIPHERAL NERVE REPAIR
Nerve autograft
[23]
Records of peripheral nerve repair date back to the Hippocratic era ; however, the techniques and
materials used for nerve gap repair have changed through the years [Figure 4]. In the 1800s, various
techniques for peripheral nerve repair were described in the literature, including segmental nerve repair
using nerve autograft , conduits of various materials [38-40] , and cellular nerve allografts . Nerve autograft is
[41]
[38]
considered the historical standard for peripheral nerve gap repair when tensionless direct nerve repair