Systematic Description and Nomenclature of Nerve Disturbances John A. Yagiela, DDS, Ph. D UCLA School of Dentistry 12 th International Dental Congress on Modern Pain Control 15 October, 2009
Peripheral nerve anatomy
Classification of nerve injuries Seddon 1943 ◦ Neuropraxia—conduction block from mild trauma, without axonal damage ◦ Axonotmesis—axonal damage with preservation of the nerve sheath but peripheral fiber degeneration ◦ Neurotmesis—nerve severance
Classification of nerve injuries (2) Sunderland 1951 ◦ First-degree injury Type 1: nerve trunk manipulation, traction, or compression Type 2: stronger nerve manipulation producing intrafascicular edema Type 3: severe nerve manipulation causing disruption of the myelin sheath, demyelinization ◦ Second-degree injury Axonal damage with intact endoneurium
Classification of nerve injuries (3) Sunderland 1951 (cont. ) ◦ Third-degree injury Axonal damage with intact perineurium ◦ Fourth-degree injury Axonal damage with intact epineurium ◦ Fifth-degree injury Complete nerve transsection
Classification comparisons Seddon Sunderland Neuropraxia First-degree, Type 1 First-degree, Type 2 First-degree, Type 3 Recovery Potential Full Axonotmesis Second-degree Third-degree Fourth-degree Neurotmesis Fifth-degree Full Slow, incomplete Neuroma/incontinuity Unpredictable
Axonotmesis repair
Clinical course Most reflective of degree of initial injury Lessening of complete anesthesia over time generally reflects Firstor Second-degree damage (Sunderland classification)
Descriptors of symptoms of sensory nerve injury (IASP) Anesthesia—loss of sensation Hypoesthesia—decreased response to stimulation Hypoalgesia—reduced pain response Paresthesia—abnormal sensation that may be evoked or spontaneous Dysesthesia—unpleasant abnormal sensation that may be evoked or spontaneous Hyperesthesia—increased response to stimulation Hyperalgesia—increased pain response Allodynia—pain produced by a non-noxious stimulus Altered taste sensation (lingual nerve)
A word on chemically induced neurotoxicity Classification schemes for traumatic injuries not necessarily applicable to chemically induced damage Different local anesthetics may target different cellular systems or even different cells to damage nerves
Скачать презентацию Systematic Description and Nomenclature of Nerve Disturbances John
Yagiela Nerve Injury.pptx