The technique of intraoperative evoked electromyography is described in detail. Direct intraoperative stimulation of the exposed facial nerve identified the sites of nerve impulse conduction blocks in 16 of 18 patients who needed decompression for Bell' s palsy. In order to determine the site of impulse conduction block the test must be performed before 100 per cent nerve degeneration occurs. The lesions extended only a few millimeters and were found to be proximal to the geniculate ganglion in 15 (94 per cent) of these patients. Schirmer's test correctly identified the sites of the lesions in only 61 per cent of the patients. To locate the precise site of the lesion inducing a conduction block in Bell's palsy, intraoperative evoked electromyography must be used. The limited extent of the blocked motor fibers indicates that segmental rather than total intratemporal decompression is needed in Bell's palsy.

Electromyography↗

PubMedDate not supplied

Effect of CO2 on the perilymphatic oxygen tension in cats.

A microelectrode with a tip of 100micron permitting recording of the oxygen tension in the perilymphatic space according to the polarographic principle and having a minimal drift of 1-25% per hour has been developed. The effects of apnea, hypo- and hyperventilation as well as those of inhalation of pure oxygen, and CO2 upon the perilymphatic PO2 have been measured by placing the electrode in the perilymph through the fenestrated stapedial footplate of 87 adult cats. The correlation between the arterial PO2 and the perilymphatic PO2 is so close that even hypo- or hyperventilation in presence of air does influence the oxygen content of the perilymphatic space. In view of the effect of the smallest accumulation of alveolar CO2, particular attention has to be paid to the system used for respiration of the experimental animal, when determining the action of drugs or inhaled gas mixtures on the oxygenation of the inner ear fluids. The measurement of the perilymphatic oxygen tension also indicates that the rate of blood flow cannot be used to deduct with accuracy the actual degree of oxygenation of the inner ear fluids.

Animals↗

PubMedDate not supplied

Perilymphatic oxygen tension and vasoactive drugs.

The oxygenation of the perilymph in response to the intravenous injection of vasoactive drugs has been measured in 67 cats using the polarographic method. Of all drugs used, only angiotensin induced a significant raise of perilymphatic PO2. Histamine, 50% glycerol and 7% Na2CO2 reduced the perilymphatic PO2. Papaverine, furosemid, pyridylcarbinol, naftidrofuryl and low molecular dextran have no significant effect upon the perilymphatic oxygen tension. Rapid changes of systemic blood pressure were found to correlate with subsequent modifications of the oxygen tension in the perilymphatic space.

Angiotensin II↗

PubMedDate not supplied

Effect of cholinergic drugs on the perilymphatic oxygen tension.

The effect of the intravenous injection of cholinergic drugs on perilymphatic oxygen tension (PO2) was measured using the polarographic method in 20 cats. Acetylcholine, pilocarpine and neostigmine produced minimal but statistically significant changes in perilymphatic PO2. Atropine and scopolamine did not influence the PO2 of the perilymphatic space. The reported results show that under normal conditions the cholinergic receptors of the vestibular vessels have little effect on the permeability of arterial PO2.

Acetylcholine↗

PubMedDate not supplied

Argon laser stapedotomy.

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Animals↗

PubMedDate not supplied

Infratemporal fossa approach for glomus tumors of the temporal bone.

The surgical experience with 74 glomus tumors of the temporal bone is presented. The article proposes new refinements in the classification of type C and D tumors and describes in detail the technique of blind sack closure of the external auditory auditory canal, double ligation of the sigmoid sinus and the use of a special infratemporal fossa retractor. The postoperative treatment and intraoperative management of the internal carotid artery, facial nerve and cranial nerves IX, X, XI and XII including the technique and results of a new type of V-VII anastomosis are discussed.

Adult↗

PubMedDate not supplied

Electroneurographic evaluation of the facial nerve. Method and technical problems.

Electroneurography (ENoG) is emerging as a useful clinical tool in evaluation of acute facial nerve paralysis. The method of test performance can have an influence on the test results. This paper describes in detail the method used to perform ENoG at the University of Zurich. The variables that affect the results and methods of avoiding technical problems are emphasized. If ENoG is to be used clinically, the examination should be performed in a manner similar to that described in reports from this institution.

Action Potentials↗