The Effects of Exogenous Modulation on the Peripheral Nerve Regeneration after Injury and Primary Surgical Repair
Journal Title: Biomedical Journal of Scientific & Technical Research (BJSTR) - Year 2018, Vol 4, Issue 3
Abstract
Peripheral nerve injury can be surgically treated, but functional recovery is still unsatisfactory. That is why additional methods that can be applied after surgical repair and which modulate nerve regeneration are sought, this regeneration involving both the morphological recovery of the axon and the myelin sheath, but also the functional, physiological recovery of the peripheral nerve. Thus, in recent years, experimental studies have been undertaken in vivo and in vitro, but also in clinical trials involving electric stimulation, low-level laser therapy and pharmacotherapy. But many of these attempts are not yet standardized and well established, although their effect on the anatomicalfunctional recovery of the peripheral nerve is indisputable. In this review we present a brief overview of the main results obtained in these researches in recent years. Regeneration of the peripheral nerve is a complex process that demands two actions: axonal sprout and demyelization. After the destruction of a portion of the peripheral nerve (by trauma, lesions or tumors), Wallerian degeneration of axon occurs, followed by a retrograde degeneration of the corresponding neurons in the spinal cord. Primary repair involves a surgical act for connection the two remaining nerve ends. Sometimes an autologous nerve graft is needed if the distance between the two nerve ends is too high [1]. The functional recovery after surgery is affected by inflammation, scar tissue formation, or the wrong direction of the axons that begin to regenerate. The axon rate of growth is slow, about 1 mm/day [2]. So, the recovery of nerve function is difficult and many times unsatisfactory. Modern surgical methods of peripheral nerve repair include the use of nanotubes from various synthetic materials [3] and the addition of stem cell to restore the Schwann cell population. These cells secrete neurotrophic and neurotropic factors that stimulate nerve regeneration [4,5]. All of these methods are widely described in the literature. The purpose of this review is to draw attention to some post-surgical methods that have been increasingly used in recent years to stimulate peripheral nerve regeneration and improve the recovery of nerve function after the surgical act has reached its goal. Such methods are electrical stimulation, low level laser therapy and pharmacotherapy. The methods proposed for exogenous modulation on injured peripheral nerve after surgical repair are depicted in Figure 1. The poor functional recovery of the peripheral nerve after injury and surgical repair makes demands for new strategies to stimulate its regeneration, like the electrical stimulation (ES). It is generally accepted that low frequencies, 20Hz or less, can accelerate the actual recovery rate, findings that were proven in both animal models and in patients [6]. It has been demonstrated that a brief electrical stimulation has a good effect on accelerating axons outgrowth at the injury site [7,8]. Experimentally, in small rodents, a continuous low frequency (20 Hz) electrical stimulation was performed for 2 weeks on the proximal part of an injured nerve by axotomy and it was observed a regeneration of all axons of the femoral motor neurons over a distance of 25mm after 3 weeks [7]. Other studies have shown that an electrical stimulation for only 1 hour induces nerve regeneration on both motor and sensory nerves. ES promotes axonal growth along the lesion site and does not affect the axonal regeneration rate at the distal end of the injured nerve [9].
Authors and Affiliations
Emilia Manole, Alexandra Bastian, Violeta Ristoiu, Sabina Zurac, Monica Neagu
Keywords
Related Articles
- EP ID EP590927
- DOI 10.26717/BJSTR.2018.04.001043
- Views 121
- Downloads 0
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