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Biomedical subjects

M Hawke

Publications and source records attributed to M Hawke.

At least 19 recordsLinked to original sources
PubMed1995

Clinical photographs as teaching aids: how reliable are they?

A study to investigate the value and reliability of clinical photographs as teaching aids was undertaken. Twenty colour photographs were taken using the StarMed video-otoscopic system. The pictures, which were a mixture of normal and abnormal ears, were shown to 21 experienced otolaryngologists from the UK and Canada. These clinicians were asked to identify the abnormality if any. The median score for correctly identified pictures was 15 (range 12-18). This score was identical for both the UK and Canadian subgroups. Although the abnormalities were consistently well recognized with an average correct identification rate of 90 per cent (range 67-100 per cent), the 'normals' were recognized significantly less well at only 41 per cent (range 5-71 per cent) (chi-squared = 110.6; 1 df; p < 0.001). This result is probably due to failure of the camera to capture the huge variation and subtleties in the range of normal, and the clinicians' natural inclination to identify pathology, when in doubt. We would conclude that as long as this failing is recognized, clinical photographs, and specifically those from the video-otoscope, represent a useful and reliable teaching tool.

Audiovisual Aids↗
PubMed1995

Diagnostic imaging of fungal sinusitis: eleven new cases and literature review.

Fungal sinusitis should always be considered in the differential diagnosis of chronic or recurring sinusitis resistant to adequate medical treatment. A high index of suspicion is necessary for the diagnosis, and the clinical examination is rarely conclusive. The definitive diagnosis depends on the pathologist in most cases. We reviewed retrospectively the imaging findings, specifically computed tomography (CT) and magnetic resonance (MR), in a series of fungal sinusitis patients. Non-enhanced CT scan is more sensitive than conventional X-ray in detecting the classical focal areas of hyper-attenuation and calcification seen in soft-tissue masses of fungal sinusitis. MR findings of hypo-intense signals on T1-weighted sequences which progress to signal-void area on T2-weighted sequences, are characteristic features of fungal sinusitis; however, it is reserved for cases where intracranial invasion is suspected or CT findings are inconclusive.

Adult↗
PubMed1995

Continuous intrathoracic pressure monitoring with a new esophageal microchip catheter in sleep-related upper airway obstructions.

A new small-diameter microchip catheter, especially developed for continuous intrathoracic pressure monitoring to assess the degree of respiratory obstruction and effort in patients with sleep-related upper airway obstructions, was investigated. The technical performance and clinical applicability of the catheter was tested in a simplified screening study comprising 122 sleep recordings in patients with varying complaints of snoring and daytime tiredness. In six obese snorers, sensitivity of the catheter to apneas, hypopneas, and nonapneic snoring was compared to the traditional assessment of respiratory events by conventional polysomnography. The catheter was found to be easy to handle and introduce, with technical qualities meeting the demands for overnight recordings of intrathoracic pressure variations. Patient tolerance was high (93%), and sensitivity to apneas and hypopneas was equivalent to that of traditional polysomnography. Periods with upper airway obstruction and increased respiratory effort on the borderline between asymptomatic obstructions and obstructions resulting in significant blood-gas changes could be detected primarily with intrathoracic pressure monitoring. Monitoring the intrathoracic pressure variations in the esophagus has been shown previously to reflect respiratory effort. Increased respiratory effort might be one of the explanations for the fragmented sleep patterns and sleep related daytime symptoms sometimes seen in patients without a pathologic respiratory index. In addition to being applicable for the detection of apneas and hypopneas, continuous nocturnal monitoring of the intrathoracic pressure variations also detects small increases in respiratory effort and thus may constitute a valuable tool for the understanding and diagnosis of upper airway resistance syndrome and obstructive sleep apnea syndrome.

Adult↗
PubMed1994

The uncinate process: a histological and morphological study.

The uncinate process (UP) has become a familiar anatomical landmark to otolaryngologists due to the increasing popularity of functional endoscopic sinus surgery (FESS) in recent years. This study examines the histological and morphological features of UPs removed from a group of patients undergoing FESS operations for chronic sinusitis. The structure of the UP by light microscopy (LM) is reported. A relatively high proportion of goblet cells and seromucous glands was noted. Scanning electron microscopy (SEM) identified four surface cell types on the UP. Furthermore, four categories of surface morphology were noted. The most common appearance was of predominantly ciliated cells. A nonciliated surface ultrastructure is associated with a longer history of sinonasal symptoms and a higher incidence of surgical intervention.

Adult↗
PubMed1994

The early development of sino-nasal mucosa.

The development of human nasal mucosa was studied in 20 fetal heads between 8 and 24 weeks of gestation. Initially the nasal cavity is lined by a single layer of flattened cells, which produces two to three layers of undifferentiated spherical cells. Olfactory epithelium lines the cranial portion of the human fetal nasal cavity at 8 weeks of gestation. Pseudostratified ciliated cuboidal or columnar epithelium appears at 9 weeks of gestation in the nasal cavity and between 14 and 16 weeks of gestation in the primitive ethmoid sinuses and maxillary sinus infundibulum. Goblet cells and glandular acini appear between 12 and 14 weeks of gestation. Initially these goblet cells/glands are found predominantly in the anterior nasal cavity but are more evenly distributed at 24 weeks of gestation. The epithelial development of the nasal septum generally precedes that of the lateral nasal wall. This study documents nasal mucosal maturation and associated anatomic development in the human fetus.

Embryonic and Fetal Development↗
PubMed1994

Computer generated three-dimensional reconstruction of the bony labyrinth in Mondini's dysplasia.

The bony labyrinth obtained at necropsy in four cases was studied by a new computer-generated three-dimensional (3-D) system. One case was normal (control) and the other three were histopathologically confirmed cases of Mondini's dysplasia. In case 1, the cochlea had only 2 turns and the lateral semicircular canal did not make a circle but appeared as a spherical mass projecting from the utricle even though the posterior semicircular canal made a normal circle. In case 2, there were no turns in the cochlea even though the semicircular canals and the vestibule appeared normal. In case 3, the cochlea showed 1 to 1 and 1/2 turns and the semicircular canals were premature showing only bud-like projections. This 3-D imaging system, which utilizes the toggling method, provides a way of obtaining satisfactory images without markers, and the time required to obtain these 3-D images was reduced by using a video camera instead of a digitizer. One of the problems associated with the use of 3-D imaging is the long processing time. We resolved this by inputting the section images with a video camera and by picking up structures using density segmentation instead of tracing with a digitizer.

Child, Preschool↗
PubMed1994

Continuing medical education interests of Canadian otolaryngologists.

A questionnaire was sent to Canadian otolaryngologists to assess their continuing medical education interests. One hundred and eighty-seven completed questionnaires were returned, a response rate of 28.5%. The categories of highest interest were nose/sinus, otology/vestibular, and general otolaryngology. Lower overall ratings were found for head and neck surgery and facial plastic/reconstructive surgery topics.

Canada↗
PubMed1993

CT imaging in the diagnosis and treatment of sinus disease: a partnership between the radiologist and the otolaryngologist.

We consider that the nasal cavity and the paranasal sinuses cannot be declared completely normal without a normal CT scan. While CT scans are clearly useful in the evaluation of patients with recurrent sinusitis, it is important to emphasize that they should not be employed exclusively for diagnosis. Nasal endoscopy and clinical evaluation still form the basis for the diagnosis of chronic and recurring sinusitis. The CT technique described should be used only to supplement the clinical data obtained during history-taking and the rhinoscopic/endoscopic examination and is essential before functional endoscopic sinus surgery. The complexity of the diagnostic process is simplified to patient benefit when the radiologist and the otolaryngologist form a functional interactive partnership.

Humans↗
PubMed1993

An anatomical study of vidian neurectomy using an endoscopic technique: a potential new application.

Vasomotor rhinitis is a common problem in contemporary rhinology. Although this disease has been described for decades, the pathophysiology and treatment are yet to be fully understood or described. A review of the literature of vasomotor rhinitis focusing mainly on pathophysiology and treatment is presented. Following detailed cadaver dissections a new treatment approach that takes advantage of endoscopic techniques has been proposed. Comparison with existing techniques and discussion of the pathophysiology of vasomotor rhinitis is presented. Treatment suggestions conclude the analysis, with the authors commending the endoscopic technique when symptoms merit division of the vidian nerve.

Cadaver↗
PubMed1993

CT scanning for functional endoscopic sinus surgery: analysis of 200 cases with reporting scheme.

An analysis of the computed tomograms of the paranasal sinuses from 200 patients with sinonasal complaints is presented. The results of our study are similar to those of other reported series despite a different patient selection. We have developed a simple systematic reporting scheme which includes all of the relevant abnormalities, and which allows a much more detailed picture of the disease pattern to be generated for both clinical use and for analytical studies.

Adolescent↗
PubMed1992

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.

Calculi↗
PubMed1992

Swirls, wrinkles and the whole ball of wax (the source of keratin in cerumen).

Recent work carried out at the Ear Pathology Research Laboratory has demonstrated that cerumen plugs consist of a large amount of keratin debris. In this study the site of origin of this keratin was investigated. This was done by histologically examining these cerumen plugs without disturbing the natural relationship between the plug and the surrounding epithelium. We have clearly demonstrated that a cerumen plug consists of keratin arising from the migratory epithelium of the deep external auditory canal and epithelium of the superficial external auditory canal.

Cadaver↗
PubMed1992

Presbycusis: correlations of clinical audiology with morphological changes in the cochlea and the ventral cochlear nucleus.

Five cases of presbycusis are presented. Analysis included audiological tests, cochlear hair cell and ganglion cell counts, assessment of degree of strial atrophy, and ventral cochlear nucleus neuron counts. One case showed a reduction in cochlear nucleus neuron counts without significant cochlear changes, indicating that this pattern of pathological changes is a possible cause of high tone sensorineural deafness.

Aged↗
PubMed1992

Nasal polyps, bronchial asthma and aspirin sensitivity.

The ASA triad comprises bronchial asthma, acetylsalicylic acid (ASA) sensitivity and nasal polyps. It presents as chronic rhinitis followed by bronchial asthma and ASA sensitivity, and later nasal polyps. The pathogenesis of the ASA triad may involve interrelationships between disease in the upper and lower airway and hypersensitivity to cyclo-oxygenase inhibiting medications. Treatment of the nasal polyps has been shown to improve the patients' asthma.

Aspirin↗