Progress in peripheral nerve reconstruction

Abstract

The development of peripheral nerve surgery over the past 15 years has been fascinating to watch. Significant improvements have been achieved by the wide application of techniques which were developed before this period. New approaches may revolutionize the tactics of nerve repair in the near future.

Human muscle–derived stem/progenitor cells promote functional murine peripheral nerve regeneration

“…Despite recent advances in microsurgical techniques and improved understanding of nerve regeneration, functional recovery following repair of transected peripheral nerves often remains disappointing (1,2). Loss of nerve and muscle function, impaired sensation, and painful neuropathies remain the major challenges (3).…”

Nervo alógeno conservado em glicerol: estudo experimental em ratos

“…Nerve autografting is the surgical treatment of choice for nerve injury cases affecting a larger segment than that where simple reapproximation and raphy are possible, with microsurgical wire (18) . However, the search for new techniques replacing nerve grafting for treating large portions of neural tissue loss, avoiding the damages caused to donor area, targeting the shortening of surgical time and functional outcomes improvement increasingly become a trend in neural regeneration literature.…”

“…It is important to highlight that the tubing method on groups B (glycerol-preserved autogenous vein) (9) and C (glycerol-preserved nerve allograft) could show some additional advantages over autografting: absence of neural sequels on the donor area, shorter surgical times, and the potential to use large donor areas when repairing large neural tissue losses. Also, the use of allografts could be regarded as a repair alternative when there is, in particular, a significant neural tissue loss (18) The key reason for an unsuccessful procedure would be the high degree of antigenicity produced, being required the use of immunosuppressant agents, with the risk of strong local rejection with their early suspension (12,18) In the evaluation of histological results, group A (autografting) showed the presence of axonal escapes, demonstrating that, despite the presence of the epineurium and the local neurotrophic factors, these were unable to drive all growing axonal fibers to the target organ.…”

“…This is probably related to preservation with glycerol, which collapsed the cells of the inner layer of the vein, as well as the muscle cells of the medium layer, making it a low antigenic structure (9) . Group B (glycerol-preserved autogenous vein) also showed less axon escape out of the boundaries of the vein, probably because the vein frame, collagen-and laminin-rich, better drives axonal growth to the injured nerve´s distal end (9) .Another aspect that could have contributed with this is the fact that tubing eliminates the need to suture nerve stumps, thus determining a milder local inflammatory response (1,2,18 ) . On group B (glycerol-preserved autogenous vein), the presence of neural mini-fascicles was found, most of these myelinated, as well as wallerian degeneration in small amounts, consistently to previous reports on scientific literature (9,13) .…”

Tissue engineered nerve constructs:where do we stand?

“…Alternative materials, including fat sheaths, gauze, bone, and metal tubes were used in an attempt to repair damaged nerves [9]. In the 1960's, Millesi introduced the concept of microsurgery, in which individual nerve fascicles in each nerve stump could be precisely aligned and tension minimized as a means to dramatically improve the success of nerve regeneration [10][11][12] There are several key properties that all guidance channels should possess: (1) they must be readily formed into a conduit having a desired diameter and wall thickness, (2) they should be simple to implant using microsurgical techniques, (3) they must be sterilizable, and (4) they should be biodegradable [13]. Permanent materials are less desireable because they may pose a more severe risk of infection, tend to provoke connective tissue responses, and can compress nerves or become dislodged.…”