Monograph: Traumatic injury to peripheral nerves
Abstract:
This article reviews the epidemiology, classification, localization, prognosis, and mecha-nisms of recovery of traumatic peripheral nerve injuries (PNIs). Electrodiagnostic (EDx) assessments are critical components of treating patients with PNIs. In particular, motor and sensory nerve conduction studies, needle electromyography, and other electro-physiological methods are useful for localizing peripheral nerve injuries, detecting and quantifying the degree of axon loss, and contributing toward treatment decisions as well as prognostication. It is critical that EDx medical consultants are aware of the tim-ing of these changes as well as limitations in interpretations. Mechanisms of recovery may include recovery from conduction block, muscle fiber hypertrophy, distal axonal sprouting, and axon regrowth from the site of injury. Motor recovery generally reaches a plateau at 18 to 24 months postinjury. When patients have complete or severe nerve injuries they should be referred to surgical colleagues early after injury, as outcomes are best when nerve transfers are performed within the first 3 to 6 months after onset.
Objectives:1) Be able to design and interpret electrodiagnostic studies to identify neuropraxia vs.
axonotmesis and neurotmesis
2) Determine and operationalize optimal timing of electrodiagnostic studies for evaluation of
peripheral nerve injuries
3) Be able to use electrodiagnostic studies to estimate prognosis and make recommendations
regarding surgical intervention
ACCREDITATION STATEMENTThe AANEM is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.
DISCLOSURE INFORMATION
Dr. Robinson has no conflicts of interest to disclose.
CREDIT DESIGNATION The AANEM designates this enduring material for a maximum of 1.0
AMA PRA Category 1 Credits TM. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
Lawrence R. Robinson, MD