Metabolic And Non-Pharmacological Modalities Involved In The Growth And Viability Of Peripheral Nerves Following Surgical Repair: A Systematic Review

Abstract

Introduction: Traumatic orthopedic injuries are commonly complicated by peripheral nerve injury in the upper and lower extremity. The repair of peripheral nerve injuries may be accomplished by autologous nerve transfer or grafting. Multiple techniques for enhancing nerve regeneration and viability have been trialed, including electrostimulation; however, there is inadequate research concerning what metabolic and non-pharmacological methods may contribute to nerve regeneration and positive postoperative outcomes following nerve transfer and grafting. The aim of this review was to identify the impact of certain factors such as nutritional status, exercise, and smoking status on nerve regeneration following surgical repair.

Methods: Published prospective, retrospective, and review articles were reviewed from the PubMed database. Relevant articles were queried using a Python PubMed scraper with combinations of various keywords, such as “nutrition”, “supplements”, “peripheral nerve grafting”, “smoking status”, “exercise”, “fitness”, “peripheral nerve repair”, “peripheral nerve transplant”, and “orthopedics”.

Results: Our literature review produced 31 unique articles published between 2001 and 2024 that focused on nonbiologic factors affecting peripheral nerve regeneration following repair. In regard to nutritional factors, articles often mentioned readily available supplements such as creatinine, sesame oil, and saffron having a biologic effect on peripheral nerve growth and support. Additional interventions, such as the integration of nanofibers containing atorvastatin and alpha lipoic acid, were also linked with improved nerve growth in animal studies involving sciatic nerve injury. When investigating the effect of smoking on peripheral nerve health, studies reported mixed findings. Some articles stated that the smoking status of the patient had no effect on the postoperative outcome following autologous digital nerve grafting, while others indicated greater recovery in two-point discrimination for their nonsmoking patients following peripheral nerve repair. A similar trend was found when investigating the effect of cardiovascular exercise on peripheral nerve health, where multiple studies referenced daily moderate intensity cycling workouts as being associated with improved axon regeneration of peripheral nerve grafts. However, other articles were unable to establish a clear link between these variables.

Discussion: Various studies have identified nutritional supplements and vitamins correlated with improved nerve viability in animal models. However, there has been insufficient clinical research on these factors in appropriate patient populations. Additionally, there is no clear consensus on the effect of exercise and smoking status on peripheral nerve viability and regeneration after injury as well. Future research should investigate the effect of nutritional supplements on nerve viability in patients as well as delineate how moderate cardiovascular exercise and smoking status affect long-term outcomes following peripheral nerve grafting and repair.

Significance: There are identifiable gaps in current research and clinical understanding regarding factors affecting nerve regeneration following repair, which warrants further investigation with formal clinical trials.

Aris Paschalidis

Medical Student

My research interests include health analytics, infectious diseases, and artificial intelligence.