Otolaryngologic clinics of North America
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Neurotransmitters and neuromodulators thought to be active on neurons in the cochlea, CN, and SOC have been reviewed. The variety of neurotransmitters and neuromodulators present and likely colocalized in these neurons are the chemical substrates that link morphologically and physiologically diverse neurons to process sound information. ⋯ Moreover, the effects of neurotransmitters and neuromodulators are not limited to synaptic transmission but serve as trophic agents for the establishment of neuronal circuitry during development and the rearrangement of synapses as a result of sensory experience or injury. An understanding of the neurochemical aspects of sensory processing at these diverse synapses then is of fundamental importance in understanding the organization of the auditory system.
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Otolaryngol. Clin. North Am. · Apr 1992
ReviewIntraoperative monitoring of facial and cochlear nerves during acoustic neuroma surgery.
The likelihood of successful preservation of facial and cochlear nerve function during acoustic neuroma surgery has been improved by the advent of intraoperative monitoring techniques. The facial nerve is monitored by recording EMG from facial muscles, with no muscle relaxants used; mechanical irritation of the nerve during surgery causes increased EMG activity, which can be detected in real time using a loudspeaker. Brief episodes of activity associated with specific surgical maneuvers aid the surgeon in avoiding damage to the nerve, whereas prolonged tonic EMG activity may reflect significant neural injury. ⋯ Cochlear nerve function is assessed by recording the ABR from ear canal and scalp electrodes or the CNAP with an electrode placed directly on the nerve at the brain stem root entry zone. The ABR is a well-known, noninvasive technique that can be adapted to intraoperative use relatively easily but is of limited utility owing to the delay inherent in signal averaging. Direct CNAP recordings require placement of an intracranial electrode in such a way as to contact the cochlear nerve without interfering with surgical access but have the distinct advantage of rapid feedback on changes in cochlear nerve status.
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The management of penetrating wounds of the neck provides several decision-making steps that remain controversial. The two basic concepts of management include the idea that all wounds deep to the platysma should be explored and (the more conservative concept) that selective neck exploration should be based on a battery of tests to identify traumatic injuries. The areas of agreement within these two schools of thought include exploration of wounds with obvious injury, exploration of wounds in which patients cannot be stabilized satisfactorily for further testing, and the idea that all patients with wounds deep to the platysma should be admitted to the hospital. ⋯ Furthermore, Noyes found that the hospital stay for patients with selective observation management not requiring a neck exploration was 2.8 days, compared with 4.2 days for patients with mandatory but negative neck explorations. A summary of diagnostic techniques and their indications in selecting patients with penetrating neck wounds for surgery is presented in Table 5. It has become apparent that both selective and mandatory explorations of neck wounds play important roles in treatment.(ABSTRACT TRUNCATED AT 400 WORDS)
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Otolaryngol. Clin. North Am. · Feb 1991
ReviewManagement of associated dental injuries in maxillofacial trauma.
Maxillofacial trauma frequently is accompanied by significant injuries to the teeth and their supporting structures. This review of these dental injuries relates their management to other priorities of the head and neck trauma patient. The controversy over management of the tooth within the line of a mandibular fracture is discussed.
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Otolaryngol. Clin. North Am. · Aug 1990
ReviewEvaluating the patient with a difficult airway for anesthesia.
Patients with difficult airways present a challenge when they must undergo anesthesia. This article examines the problems inherent in evaluating patients with difficult airways for surgery. The authors believe that these patients are best evaluated in a Difficult Airway Clinic. The structure and organization of such clinics are examined.