New method for the objective evaluation of injury to the lingual nerve after operation on third molars

TY - JOUR

T1 - New method for the objective evaluation of injury to the lingual nerve after operation on third molars

AU - Renton, T

AU - Thexton, A

AU - McGurk, M

PY - 2005/6

Y1 - 2005/6

N2 - Existing tests of function of the lingual nerve are either subjective or, when they elicit the jaw-opening reflex, are dependent on the cooperation of the subject. We report a study in 12 healthy volunteers and 12 patients with iatrogenic injury to the lingual nerve. A bite block (containing stimulating electrodes) was held between the teeth and the tongue was held on to the electrodes by suction. When the lingual nerve was intact, an electrical stimulus elicited brief inhibition of masseteric electromyographic activity. Local analgesia and iatrogenic injury to the lingual nerve altered nerve conduction and caused a reduction in reflex inhibition. Two methods, compatible with limited numbers of applications of the stimulus, were used to quantify responses. One used an indirect measurement of intervals between action potentials of muscle and the other used a measurement of rectified signals falling below the mean amplitude before and after the stimulus. Both methods gave values that correlated with subjective sensations. The first gave an estimate of the probability of defining major malfunction of the nerve objectively; the second gave a linear measurement that allowed recovery of the nerve to be followed.

AB - Existing tests of function of the lingual nerve are either subjective or, when they elicit the jaw-opening reflex, are dependent on the cooperation of the subject. We report a study in 12 healthy volunteers and 12 patients with iatrogenic injury to the lingual nerve. A bite block (containing stimulating electrodes) was held between the teeth and the tongue was held on to the electrodes by suction. When the lingual nerve was intact, an electrical stimulus elicited brief inhibition of masseteric electromyographic activity. Local analgesia and iatrogenic injury to the lingual nerve altered nerve conduction and caused a reduction in reflex inhibition. Two methods, compatible with limited numbers of applications of the stimulus, were used to quantify responses. One used an indirect measurement of intervals between action potentials of muscle and the other used a measurement of rectified signals falling below the mean amplitude before and after the stimulus. Both methods gave values that correlated with subjective sensations. The first gave an estimate of the probability of defining major malfunction of the nerve objectively; the second gave a linear measurement that allowed recovery of the nerve to be followed.

KW - Molar, Third

KW - Iatrogenic Disease

KW - Humans

KW - Electromyography

KW - Recovery of Function

KW - Electric Stimulation

KW - Sensation

KW - Sensory Thresholds

KW - Touch

KW - Masseter Muscle

KW - Adult

KW - Neural Conduction

KW - Tongue

KW - Reflex

KW - Time Factors

KW - Male

KW - Lidocaine

KW - Action Potentials

KW - Lingual Nerve

KW - Neural Inhibition

KW - Anesthetics, Local

KW - Postoperative Complications

KW - Lingual Nerve Injuries

KW - Middle Aged

KW - Female

U2 - 10.1016/j.bjoms.2004.11.014

DO - 10.1016/j.bjoms.2004.11.014

M3 - Article

C2 - 15888360

SN - 1532-1940

VL - 43

SP - 238

EP - 245

JO - British Journal of Oral and Maxillofacial Surgery

JF - British Journal of Oral and Maxillofacial Surgery

IS - 3

ER -