Michael Hawke

The incidence and distribution of cupular deposits in the labyrinth

Findings of large basophilic staining deposits on the cupula of the posterior semicircular canal ampulla have been used in part to explain the clinical phenomenon of benign positional vertigo (BPV). Although it is generally agreed that cupulolithiasis may involve other canal ampullae, the precise nature, distribution, and origin of these deposits remains unclear. In order to provide a better understanding of this finding, a series of 566 temporal bone specimens from the Ear Pathology Research Laboratory at the University of Toronto were reviewed. The results from this survey and speculations concerning the nature and formation of these deposits are discussed.

Pharyngeal suspension suture with Repose bone screw for obstructive sleep apnea

OBJECTIVE: Multilevel surgery for obstructive sleep apnea syndrome (OSA) may improve success. This studys goal is to prospectively evaluate the feasibility and short-term subjective effectiveness of a new tongue-suspension technique. METHODS: A multicenter nonrandomized open enrollment trial used the Repose device to treat tongue obstruction in 39 snoring and OSA patients. Outcomes include 1- and 2-month subjective reports of general health, snoring, and sleep. RESULTS: Twenty-three patients completed 1 month and 19 completed 2 months of follow-up. In OSA patients, activity level, energy/fatigue, and sleepiness improved. Two-month outcomes were less (activity level, energy/fatigue, and sleepiness). Fewer changes were observed in snorers than in OSA patients. There were 6 complications (18%), including sialadenitis (4), gastrointestinal bleeding (1), and dehydration (1) after the procedure. CONCLUSION: A pharyngeal suspension suture changes subjective outcomes. Improvement is incomplete. The procedure is nonexcisional, but significant complications may occur. Further evaluation is required to demonstrate effectiveness.

Control of bleeding in endoscopic sinus surgery: Use of a novel gelatin-based hemostatic agent

OBJECTIVE To determine whether FloSeal Matrix Hemostatic Sealant is a safe and effective means of controlling bleeding post-endoscopic sinus surgery (ESS) and to assess postoperative healing. DESIGN Prospective clinical study. SETTING University of Toronto. METHODS Eighteen patients with FloSeal placed on a total of 30 operative sites post-ESS. Time to cessation of bleeding was assessed intraoperatively. Patients had the operative sites assessed at 30 days postoperatively. MAIN OUTCOME MEASURES Effectiveness of FloSeal in controlling bleeding and aiding in healing of the operative site. RESULTS FloSeal adequately controls postoperative bleeding in patients post-ESS. Healing was also not adversely affected. CONCLUSIONS FloSeal is a safe and effective treatment for controlling blood loss after EES. It may also provide support to the middle meatus as well as improve healing of the operative site compared with the use of traditional nasal packing. However, randomized clinical trials are needed to further evaluate this.

Histamine Levels in Middle Ear Effusions

The presence of histamine in 131 middle ear effusions was determined by the fluorometric assay technique. This potent mediator of inflammation was found in significant amounts in most of the samples, suggesting that it may play an important role in the pathogenesis of otitis media with effusion. It is postulated that mast cells located in the lamina propria of the tympanic mucoperiosteum are triggered to degranulate and release histamine by anaphylatoxin derived from activation of the complement system.

The Function of Migratory Epidermis in the Healing of Tympanic Membrane Perforations in Guinea-pig: A Photographic Study

During observations on healing traumatic perforations in guinea-pig tympanic membranes, a specific appearance was seen on the surface of the epidermis as it closed the perforations. In this experiment, this pattern was identified on 15 tympanic membranes in 10 guinea pigs, and serial photography was used to record the healing process in 6 perforations over 5 days. This study shows that epidermis accumulates at the inferior margin of the perforation (the side from which it migrates) and then closes over the defect. Epidermal migration appears to be a key factor in this healing process.

Sudden Hearing Loss Due to Aids-Related Cryptococcal Meningitis—A Temporal Bone Study

We have presented the clinical history and temporal bone findings in a patient who manifested sudden hearing loss, and who subsequently was found to have cryptococcal meningitis associated with AIDS. The histopathologic findings are similar to earlier reports in patients without AIDS. Because cryptococcal infection is so much more common in AIDS patients than in the general population, it must be considered a causative factor when presented with an AIDS patient with progressive or sudden hearing loss. This offers the patient a chance for timely and effective treatment.

Histopathology of the temporal bone in osteogenesis imperfecta congenita: A report of 5 cases†

The histopathologic findings in 8 temporal bones from 5 patients with osteogenesis imperfecta congenita are reported. The otic capsule, bony walls of middle ear, and ossicles showed evidence of both deficient and abnormal ossification. Microfractures were found in the otic capsule and in the anterior process and handle of the malleus, in addition to their common location at the crurn of the stapes. The cochlear and vestibular end‐organs appeared normal. Pathologic changes compatible with otosclerosis were not seen. The possible implication of these changes on hearing and balance is discussed.

Bone Resorption in Chronic Otitis Media the Role of Mast Cells

Twenty-two surgical specimens of eroded middle ear ossicles were removed from patients with chronic otitis media, with and without cholesteatoma. By using specific mast cell stains, increased numbers of mast cells were found in connective or granulation tissue adjacent to eroded surface of the bone. Mast cells possess the biological machinery necessary for enhancing bone resorption, and the population density of mast cells is increased in a variety of disorders that are associated with bone resorption. It is hypothesized that mast cells contribute to bone resorption in chronic otitis media, and the possible mechanisms by which mast cells exert their action are discussed.

An Ink Impregnation Study of the Migratory Skin in the External Auditory Canal of the Guinea-pig

If the tympanic membrane or attic skin is wounded with a fine needle dipped in ink, ink particles are introduced into the epidermis and underlying tissue. These particles are subsequently taken up by cells in the epidermis and dermis. In this experiment the distribution of ink within the skin of ear canal was studied in nineteen guinea-pigs, one to ten days after wounding. Examination of the intact canal reveals that ink becomes distributed along a precise line from the wound to the point of desquamation. On sectioned tissue, the ink in this line is found to be mainly intracellular, initially in the epidermis, and subsequently in the upper dermis. When considered with other evidence, these results indicate that migration probably occurs in the deeper layers of the epidermis, and that it stops at the junction of the deep and superficial parts of the ear canal.

Histopathologic consequences of surgical approaches to the singular nerve

Selective sectioning of the singular nerve has proven successful in the relief of incapacitating benign positional vertigo (BPV), presumably on the histopathologic basis of posterior am‐pullary cupulolithiasis. Although the surgical techniques of transmeatal and the recently introduced retrosigmoid IAC approach have been well described, little has been written about the singular nerves anatomical relationships determined histo‐logically for each surgical approach. The anatomical relationships of the singular nerve in both the transmeatal and retrosigmoid IAC approaches are discussed.