Hayes H. Wanamaker

An algorithm for the management of acoustic neuromas regarding age, hearing, tumor size, and symptoms.

An algorithm has evolved for the management of patients with acoustic neuroma. Decisions as to surgery vs. observation, surgical approach, and whether hearing preservation should be attempted depend on age, patient symptoms, size of the tumor, residual hearing, and degree of facial nerve involvement at the time of surgery. Conservative management is used for patients over 65 years of age. This consists of observation or subtotal resection through a translabyrinthine approach, depending on the absence or presence of brainstem signs or symptoms. In patients under 65 years of age, hearing preservation is attempted through the retrosigmoid approach in tumors 1.5 cm or less if pure-tone average is less than 30 dB and the discrimination score is greater than 70%. The translabyrinthine approach is our preferred approach for tumors of any size when hearing is not serviceable. A near-total excision is performed when the facial nerve cannot be separated from the tumor. The rationale for this algorithm in the management of 130 cases of acoustic neuroma over the past 17 years is presented.

Role of Haller's cell in headache and sinus disease: a case report.

Although anatomic variations in the development of the nose and paranasal sinuses such as the Hallers cell do not themselves represent a disease state, in many cases they are responsible for the patients symptoms. Particularly in the absence of extensive associated mucosal changes, these conditions may be easily overlooked unless specifically sought. Hallers cells may cause recurrent or chronic sinusitis and persistent sinugenic headache, without significant findings on physical examination including nasal endoscopy. The presence of Hallers cells on coronal CT in a patient with corresponding symptoms deserves consideration as the potential cause of the symptoms. When medical therapy is ineffective, such cases respond well to surgical therapy through the functional endoscopic approach.

Direct Round Window Application of Gentamicin with Varying Delivery Vehicles: A Comparison of Ototoxicity

OBJECTIVE: To evaluate patterns of ototoxic damage sustained from gentamicin applied directly to the round window in varying delivery vehicles. SETTING: The search for a reliable method of drug delivery to the inner ear continues. Vehicles such as Gelfoam, hyaluronic acid, and fibrin may allow for a more reproducible pattern of ototoxic damage. STUDY DESIGN: Histological evaluation of vestibular and cochlear damage was performed on Mongolian gerbils after a known dosage of gentamicin in different delivery vehicles. RESULTS: Variable ototoxic damage was caused by Gelfoam and fibrin-based vehicles. No ototoxic damage was found in the Healon vehicle. The vehicle of fibrin and Gelfoam combined resulted in severe damage. There was no evidence of selective cochlear or vestibular ototoxicity in any of the vehicles tested. CONCLUSIONS AND SIGNIFICANCE: The fibrin/Gelfoam vehicle was the only delivery system to produce reliable damage. Ototoxic damage depended on the vehicle. We found no evidence for selective vestibular ototoxicity with gentamicin.

Blood flow and assessment of capillaries in the aging rat posterior canal crista

Vascular change has been proposed as an etiological factor in inner ear aging and in several inner ear disorders. Moreover, some successful medical management of the episodic vertigo and tinnitus associated with Ménières disease has been directed toward pharmacologically increasing blood flow, changing vascular permeability or ion homeostasis. While there are many studies of cochlear capillary morphology and blood flow, there are very few examining these variables in the vestibular system and none with respect to aging. The purpose of this study was to examine the rat posterior canal ampullary crista for age-related changes in blood flow and capillary morphology. By combining stereological techniques with microsphere injection, we have determined that in the rat posterior canal crista there is a statistically significant age-related decrease in blood flow (75%), mean capillary diameter (31%), and volume fraction of capillary lumen (31%). There is also an overall 18% decrease in the volume of the ampullary crista, a 72% decrease in blood flow/unit volume and a 36% increase in capillary length/unit volume. There were no significant changes in the capillary surface area/unit volume, the absolute capillary length, or the absolute capillary surface area. These data suggest impaired blood flow and degenerative loss of the ampullary crista may be relate to impaired end organ function.

Blood Flow and Capillary Surface Area of Rat Posterior Canal Ampulla

Vascular disorders have often been proposed to explain disorders of the inner ear, in both the cochlear and vestibular systems. While the cochlea has been extensively studied, little work has been done on vestibular blood flow. Existing studies have reported only total vestibular blood flow, using microspheres. By combining the physiologic technique of microsphere injection with new developments in morphologic stereology studies, data on end-organ blood flow (excluding nerve; 0.074 ± 0.027 μl/min; 5.99 μl/min/mm3), capillary surface area (10.87 mm2/mm3), mean capillary diameter (9.64 μm), and end-organ volume (0.013 mm3) was determined for the posterior canal ampulla of young Fischer 344 rats. Results indicate an anatomic basis for increases in blood flow with CO2 breathing, and provide an assessment of appropriate microsphere size for vestibular blood flow studies. By allowing comparison of blood flow and capillary parameters related to surface area and volume, this new method of blood flow study will allow more meaningful data to be collected on the vestibular system.

The effects of sound conditioning on gentamicin‐induced vestibulocochlear toxicity in gerbils

Recent studies in animal models have shown via physiologic and histologic measures that the administration of exogenous antioxidants is protective against gentamicin‐induced oto‐vestibulo toxicity. In addition, studies have also shown that sound conditioning increases cochlear antioxidants. The objective of this study is to determine whether sound conditioning provides protection against gentamicin in the cochlear and/or vestibular system.

Surgical treatment of benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo (BPPV) is reported to be the most common cause of inner ear vertigo seen in otologic practice. Symptoms, although distressing, are usually self-limited and resolve spontaneously over a few days to several weeks. Although conservative management, including repositioning maneuvers, is usually sufficient for relief of the symptoms of BPPV, a small group of patients will have refractory chronic or recurrent symptoms that they consider disabling. Of the options available for surgical treatment of BPPV, posterior canal occlusion seems to offer the most consistent and reproducible results, with excellent cure rates and low incidence of hearing loss and other complications.

Vestibular neurectomy: A histological and clinical study of results

Posterior fossa vestibular neurectomy has become one of the most effective surgical procedures for control of vertigo symptoms in Menières disease. A small group of patients continue to have vertigo and demonstrable vestibular function by electronystagmography (ENG) post-operatively. Another group of patients may have no vertigo, despite residual vestibular function on caloric testing. In an effort to correlate histological findings with clinical outcome, nerve biopsies were taken from seven patients undergoing vestibular neurectomy. Fibre counts of nerve biopsies were compared with clinical, audiometric and ENG results. Results of this study demonstrate that complete reduction of vestibular response (on caloric testing) and clinical cure of vertigo can be obtained despite a variable number of nerve fibres at vestibular neurectomy.

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