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Nerve Anaesthesia (nerve + anaesthesia)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

The effect of bilateral glossopharyngeal nerve anaesthesia on swallowing in horses

EQUINE VETERINARY JOURNAL, Issue 1 2005
E. A. KLEBE
Summary Reasons for performing study: Dysfunction of the glossopharyngeal nerve has been implicated as a cause of dysphagia in horses. However, recent studies have indicated that this is not the case. Objectives: To determine whether bilateral glossopharyngeal nerve anaesthesia would cause dysphagia in horses or result in measurable alterations in the timing, function, or sequence of swallowing. Methods: Swallowing was evaluated in 6 normal horses with and without bilateral glossopharyngeal nerve anaesthesia. Swallowing dynamics were assessed subjectively and objectively based on time from prehension of food until swallowing, number of tongue movements until initiation of swallowing, depth of bolus at the base of the tongue prior to initiation of swallow and evidence of tracheal aspiration using fluoroscopy and endoscopy. Results: There was no evidence of aspiration or dysphagia in horses before or after bilateral glossopharyngeal nerve block. No observed or measured differences in swallowing sequence or function could be detected in blocked compared to unblocked horses. However, there was a trend in blocked horses for the number of tongue pushes and the time to swallowing to be increased. Conclusions: Glossopharyngeal nerve function may not be essential for normal swallowing function in otherwise healthy horses. Potential relevance: Clinically, normal swallowing is not an appropriate test of glossopharyngeal nerve function and dysphagic horses should not be assumed to have glossopharyngeal nerve dysfunction. [source]

Effects of stylopharyngeus muscle dysfunction on the nasopharynx in exercising horses

EQUINE VETERINARY JOURNAL, Issue 4 2004
C. TESSIER
Summary Reasons for performing study: Nasopharyngeal collapse has been observed in horses as a potential cause of exercise intolerance and upper respiratory noise. No treatment is currently available and affected horses are often retired from performance. Objective: To determine the effect of bilateral glossopharyngeal nerve block and stylopharyngeus muscle dysfunction on nasopharyngeal function and airway pressures in exercising horses. Methods: Endoscopic examinations were performed on horses at rest and while running on a treadmill at speeds corresponding to HRmax50, HRmax75 and HRmax, with upper airway pressures measured with and without bilateral glossopharyngeal nerve block. Results: Bilateral glossopharyngeal nerve block caused stylopharyngeus muscle dysfunction and dorsal nasopharyngeal collapse in all horses. Peak inspiratory upper airway pressure was significantly (P = 0.0069) more negative at all speeds and respiratory frequency was lower (P = 0.017) in horses with bilateral glossopharyngeal nerve block and stylopharyngeus muscle dysfunction compared to control values. Conclusions: Bilateral glossopharyngeal nerve anaesthesia produced stylopharyngeus muscle dysfunction, dorsal pharyngeal collapse and airway obstruction in all horses. Potential relevance: The stylopharyngeus muscle is probably an important nasopharyngeal dilating muscle in horses and dysfunction of this muscle may be implicated in clinical cases of dorsal nasopharyngeal collapse. Before this information can be clinically useful, further research on the possible aetiology of stylopharyngeus dysfunction and dysfunction of other muscles that dilate the dorsal and lateral walls of the nasopharynx in horses is needed. [source]

Contribution of the pudendal nerve to sensation of the distal rectum

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2005
C. L. H. Chan
Background: Anal and rectal sensory mechanisms and pudendal nerve function are important in the control of faecal continence. The contribution of the pudendal nerve to sensation of the distal rectum was investigated. Methods: Heat thresholds in the anal canal, distal and mid rectum were measured using a specially designed thermoprobe. Rectal sensory threshold volumes were measured using the balloon distension method. Needle electrodes were inserted into the external anal sphincter. Pudendal nerve block was performed through a perineal approach, and completeness assessed by loss of electromyographic activity. Heat and rectal volume thresholds were measured again following unilateral and bilateral pudendal nerve block. Results: The technique was successful in four of six volunteers. Bilateral pudendal nerve block produced complete anaesthesia to heat in the anal canal (P = 0·029), but had no effect on heat thresholds in the distal or mid rectum. Rectal sensory threshold volumes were also unaffected by pudendal nerve anaesthesia. Conclusion: Anal canal sensation is subserved by the pudendal nerve, but this nerve is not essential to nociceptive sensory mechanisms in the distal or mid rectum. The transition between visceral control mechanisms in the lower rectum and somatic mechanisms in the anal canal may have functional importance in the initiation of defaecation and the maintenance of continence. Copyright © 2005 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source]