Surgery Neuroregeneration

1 surgery

1.1 prognosis
1.2 autologous nerve grafting
1.3 allografts , xenografts

surgery

surgery can done in case peripheral nerve has become cut or otherwise divided. called peripheral nerve reconstruction. injured nerve identified , exposed normal nerve tissue can examined above , below level of injury, magnification, using either loupes or operating microscope. if large segment of nerve harmed, can happen in crush or stretch injury, nerve need exposed on larger area. injured portions of nerve removed. cut nerve endings reapproximated using small sutures. nerve repair must covered healthy tissue, can simple closing skin or can require moving skin or muscle provide healthy padded coverage on nerve. type of anesthesia used depends on complexity of injury. surgical tourniquet used.

prognosis

the expectations after surgical repair of divided peripheral nerve depends on several factors:

age: recovery of nerve after surgical repair depends on age of patient. young children can recover close-to-normal nerve function. in contrast, patient on 60 years old cut nerve in hand expect recover protective sensation; is, ability distinguish hot/cold or sharp/dull.
the mechanism of injury: sharp injuries, such knife wound, damage short segment of nerve, availing direct suture. in contrast, nerves divided stretch or crush may damaged on long segments. these nerve injuries more difficult treat , have poorer outcome. in addition, associated injuries, injury bone, muscle , skin, can make nerve recovery more difficult.
the level of injury: after nerve repaired, regenerating nerve endings must grow way target. example, nerve injured @ wrist provides sensation thumb must grow end of thumb in order provide sensation. return of function decreases increased distance on nerve must grow.

autologous nerve grafting

currently, autologous nerve grafting, or nerve autograft, known gold standard clinical treatments used repair large lesion gaps in peripheral nervous system. important nerves not repaired under tension, otherwise happen if cut ends reapproximated across gap. nerve segments taken part of body (the donor site) , inserted lesion provide endoneurial tubes axonal regeneration across gap. however, not perfect treatment; final outcome limited function recovery. also, partial deinnervation experienced @ donor site, , multiple surgeries required harvest tissue , implant it.

when appropriate, nearby donor may used supply innervation lesioned nerves. trauma donor can minimized utilizing technique known end-to-side repair. in procedure, epineurial window created in donor nerve , proximal stump of lesioned nerve sutured on window. regenerating axons redirected stump. efficacy of technique partially dependent upon degree of partial neurectomy performed on donor, increasing degrees of neurectomy giving rise increasing axon regeneration within lesioned nerve, consequence of increasing deficit donor.

some evidence suggests local delivery of soluble neurotrophic factors @ site of autologous nerve grafting may enhance axon regeneration within graft , expedite functional recovery of paralyzed target. other evidence suggests gene-therapy induced expression of neurotrophic factors within target muscle can enhance axon regeneration. accelerating neuroregeneration , reinnervation of denervated target critically important in order reduce possibility of permanent paralysis due muscular atrophy.

allografts , xenografts

variations on nerve autograft include allograft , xenograft. in allografts, tissue graft taken person, donor, , implanted in recipient. xenografts involve taking donor tissue species. allografts , xenografts have same disadvantages autografts, in addition, tissue rejection immune responses must taken account. immunosuppression required these grafts. disease transmission becomes factor when introducing tissue person or animal. overall, allografts , xenografts not match quality of outcomes seen autografts, necessary when there lack of autologous nerve tissue.