Axonotmesis mainly follows a stretch injury. These stretch injuries can either dislocate joints or fracture a limb, due to which peripheral nerves are severed. If the sharp pain from the exposed axon of the nerve is not observed, one can identify a nerve injury from abnormal sensations in their limb. A doctor may ask for a nerve conduction velocity (NCV) test to completely diagnose the issue. If diagnosed as nerve injury, electromyography performed after 3 to 4 weeks shows signs of denervations and fibrillations, or irregular connections and contractions of muscles.[2]
A nerve contains sensory fibers, motor fibers, or both. Sensory fibers lesions cause the sensory problems below to the site of injury. Motor fibers injuries may involve lower motor neurons, sympathetic fibers, and or both.
In assessment, sensory-motor defects may be mild, moderate, or severe. Damage to motor fibers results in paralysis of the muscles. Nervous plexus injuries create more signs and symptoms from sensory-motor problems (such as brachial plexus injuries). In these cases, the prognosis depends on the amount of damage and the degree of functional impairment.
EMG and NCV findings
Changes in EMG
Electromyography (EMG) is a medical test performed to evaluate and record the electrical activity (electromyogram) produced by skeletal muscles using an instrument called electromyograph. In axonotmesis, EMG changes (2 to 3 weeks after injury) in the denervated muscles include:
Fibrillation potentials (FP)
Positive sharp waves
Changes in NCV (nerve conduction velocity)
EMG test is often performed together with another test called nerve conduction study, which measures the conducting function of nerves. NCV study shows loss of nerve conduction in the distal segment (3 to 4 days after injury). According to NCV study, in axonotmesis there is an absence of distal sensory-motor responses.
Treatment
Schwann cells provide the nerve with protection through the production of Nerve Growth Factors, and because these cells are intact this kind of nerve injury can be cured and normal feeling and sensations can be restored. Surgery can be done in order to help the nerve heal. The surgery will help with nerve regeneration, providing guidance to the nerve sprouts on where to attach on the proximal side of the injury. Damaged nerve axons can reattach themselves after surgery.[3] Treatment of axonotmesis also consists of:
Physical therapy or Occupational Therapy. Physical or Occupational therapy aims include:
The prognosis is usually good in terms of recovery. Rate of recovery depends on the distance from the site of injury, and axonalregeneration can go up to 1 inch per month. Complete recovery can take anywhere from 6 months to a year.[6]
^ abMenorca, Ron M. G.; Fussell, Theron S.; Elfar, John C. (2017-05-05). "Peripheral Nerve Trauma: Mechanisms of Injury and Recovery". Hand clinics. 29 (3): 317–330. doi:10.1016/j.hcl.2013.04.002. ISSN 0749-0712. PMC4408553. PMID 23895713.
^Prince, Jim McMorran, Damian Crowther, Stew McMorran, Steve Youngmin, Ian Wacogne, Jon Pleat, Clive. "Sunderland classification of nerve injuries - General Practice Notebook". www.gpnotebook.co.uk. Retrieved 2017-05-05.
^Goubier, Jean-Noel (2015). Nerve and Nerve Injuries, 1st Edition. Vol 2: Pain, Treatment, Injury, Disease and Future Directions. London: Academic Press. p. 604. ISBN9780128026533.
^Otto D. Payton & Richard P. Di Fabio et al. Manual of physical therapy. Churchill Livingstone Inc. Page 24. ISBN0-443-08499-8
February 05, 2023
axonotmesis, injury, peripheral, nerve, extremities, body, axons, their, myelin, sheath, damaged, this, kind, injury, endoneurium, perineurium, epineurium, remain, intact, motor, sensory, functions, distal, point, injury, completely, lost, over, time, leading,. Axonotmesis is an injury to the peripheral nerve of one of the extremities of the body The axons and their myelin sheath are damaged in this kind of injury but the endoneurium perineurium and epineurium remain intact Motor and sensory functions distal to the point of injury are completely lost over time leading to Wallerian degeneration due to ischemia or loss of blood supply Axonotmesis is usually the result of a more severe crush or contusion than neurapraxia 1 Axonotmesis of the nerve Axonotmesis mainly follows a stretch injury These stretch injuries can either dislocate joints or fracture a limb due to which peripheral nerves are severed If the sharp pain from the exposed axon of the nerve is not observed one can identify a nerve injury from abnormal sensations in their limb A doctor may ask for a nerve conduction velocity NCV test to completely diagnose the issue If diagnosed as nerve injury electromyography performed after 3 to 4 weeks shows signs of denervations and fibrillations or irregular connections and contractions of muscles 2 Contents 1 Injury classification 1 1 Sunderland s Stage II classification 1 2 Sunderland s Stage III classification 1 3 Sunderland s Stage IV classification 2 Assessment 3 EMG and NCV findings 3 1 Changes in EMG 3 2 Changes in NCV nerve conduction velocity 4 Treatment 5 Prognosis 6 See also 7 ReferencesInjury classification EditThere are two kinds of nerve injury classifications 3 Seddon SunderlandNeurapraxia Grade IAxonotmesis Grade IINeurotmesis Grade IIINeurotmesis Grade IVNeurotmesis Grade VSunderland s Stage II classification Edit Endoneurial tube remains intact Emergence of Wallerian degeneration Can be detected with Tinel s sign 4 5 Sunderland s Stage III classification Edit Endoneurial tube is damaged Perineurium remains intact Scarring occurs Intrafascicular fibrosis occurs due to edemaSunderland s Stage IV classification Edit Perineurium is damaged Epineurium remains intact Neuroma could occur Surgery is required for treatmentAssessment EditA nerve contains sensory fibers motor fibers or both Sensory fibers lesions cause the sensory problems below to the site of injury Motor fibers injuries may involve lower motor neurons sympathetic fibers and or both Assessment items include Sensory fibers that send sensory information to the central nervous system Motor fibers that allow movement of skeletal muscle Sympathetic fibers that innervate the skin and blood vessels of the four extremities In assessment sensory motor defects may be mild moderate or severe Damage to motor fibers results in paralysis of the muscles Nervous plexus injuries create more signs and symptoms from sensory motor problems such as brachial plexus injuries In these cases the prognosis depends on the amount of damage and the degree of functional impairment EMG and NCV findings EditChanges in EMG Edit Electromyography EMG is a medical test performed to evaluate and record the electrical activity electromyogram produced by skeletal muscles using an instrument called electromyograph In axonotmesis EMG changes 2 to 3 weeks after injury in the denervated muscles include Fibrillation potentials FP Positive sharp wavesChanges in NCV nerve conduction velocity Edit EMG test is often performed together with another test called nerve conduction study which measures the conducting function of nerves NCV study shows loss of nerve conduction in the distal segment 3 to 4 days after injury According to NCV study in axonotmesis there is an absence of distal sensory motor responses Treatment EditSchwann cells provide the nerve with protection through the production of Nerve Growth Factors and because these cells are intact this kind of nerve injury can be cured and normal feeling and sensations can be restored Surgery can be done in order to help the nerve heal The surgery will help with nerve regeneration providing guidance to the nerve sprouts on where to attach on the proximal side of the injury Damaged nerve axons can reattach themselves after surgery 3 Treatment of axonotmesis also consists of Physical therapy or Occupational Therapy Physical or Occupational therapy aims include Pain relief Maintain range of motion Reducing muscular atrophy Patient education Use of assistive devices Orthotic needs Prognosis EditThe prognosis is usually good in terms of recovery Rate of recovery depends on the distance from the site of injury and axonal regeneration can go up to 1 inch per month Complete recovery can take anywhere from 6 months to a year 6 See also EditConnective tissue in the peripheral nervous system Nerve Nerve fiber Nerve injury Neurapraxia Neuroregeneration Neurotmesis Peripheral nerve injury Seddon s classification Wallerian degenerationReferences Edit Saidoff David C McDonough Andrew 2002 Critical Pathways in Therapeutic Intervention Missouri Mosby Inc p 262 ISBN 0 323 00105 X Nerve Injury Neuropraxia Axonotmesis Neurotmesis and Healing Healthhype com www healthhype com Retrieved 2017 05 03 a b Menorca Ron M G Fussell Theron S Elfar John C 2017 05 05 Peripheral Nerve Trauma Mechanisms of Injury and Recovery Hand clinics 29 3 317 330 doi 10 1016 j hcl 2013 04 002 ISSN 0749 0712 PMC 4408553 PMID 23895713 Prince Jim McMorran Damian Crowther Stew McMorran Steve Youngmin Ian Wacogne Jon Pleat Clive Sunderland classification of nerve injuries General Practice Notebook www gpnotebook co uk Retrieved 2017 05 05 Goubier Jean Noel 2015 Nerve and Nerve Injuries 1st Edition Vol 2 Pain Treatment Injury Disease and Future Directions London Academic Press p 604 ISBN 9780128026533 Otto D Payton amp Richard P Di Fabio et al Manual of physical therapy Churchill Livingstone Inc Page 24 ISBN 0 443 08499 8 Retrieved from https en wikipedia org w index php title Axonotmesis amp oldid 1114726900, wikipedia, wiki, book, books, library,
