Denervaatio

Denervation, or denervaatio, refers to the loss or removal of nerve supply to a part of the body. It can result from injury, disease, or intentional medical procedures and may affect motor, sensory, or autonomic nerves. Denervation can be complete or partial and may lead to functional changes in the affected tissues.

Mechanisms of denervation include transection or severing of a nerve, chronic compression, ischemia, inflammation, or degenerative processes. When peripheral nerves are damaged, the distal portion undergoes Wallerian degeneration. If the proximal stump remains viable, axons may regenerate and reinnervate target tissue, but recovery is not guaranteed and depends on factors such as distance to the target, nerve type, and duration of denervation.

Denervation can be achieved by various methods. Surgical denervation involves cutting or removing a nerve or its branches. Chemical denervation uses neurolytic agents (for example phenol or alcohol) to destroy nerve fibers. Thermal methods, including radiofrequency ablation and cryoablation, create lesions to interrupt nerve conduction. Denervation is sometimes performed for pain control or to treat disorders involving excessive nerve activity. Autonomic denervation can occur as part of disease or be performed therapeutically, such as renal denervation in resistant hypertension or cardiac sympathetic denervation in select conditions.

Clinical consequences of denervation include loss of movement and/or sensation in the affected area, muscle atrophy, trophic changes, and possible neuropathic pain or hypersensitivity if partial reinnervation occurs. Diagnosis typically involves clinical assessment, electrodiagnostic tests (EMG, nerve conduction studies), and imaging to determine the extent and cause of denervation. Prognosis varies with the extent of nerve injury and the potential for nerve regeneration.