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Biomedical subjects

M D Atlas

Publications and source records attributed to M D Atlas.

18 recordsLinked to original sources
PubMed2006

Utilization of fresh human tympanic membranes for structural analysis and cytokeratin immunocytochemistry implementing resin techniques.

CONCLUSIONS: The results of this study have demonstrated for the first time that tympanic membrane (TM) structure is preserved following removal of fresh, normal tissue from patients undergoing surgery. Greater clarity has been demonstrated using resin sections than in previous studies on paraffin sections. Of particular note, cytokeratin (CK) immunocytochemistry was successfully performed on resin sections, which has not been previously reported. This may have potential applications for future work involving tissues that express CKs. OBJECTIVES: To analyse the structure of normal, fresh human TM specimens after surgical removal and to evaluate their CK immunocytochemistry using resin techniques, neither of which have been demonstrated previously. MATERIAL AND METHODS: Seven TM specimens were removed during surgery and then preserved in a modified Karnovsky's fixative. Semi-thin and thin sections were examined by means of light and electron microscopy, respectively. For comparison purposes, paraffin block-embedded specimens were also sectioned. CK immunocytochemistry was performed on semi-thin sections using standard immunoperoxidase techniques, with expression being demonstrated using light microscopy. RESULTS: The three-layer architecture of the TM was preserved. The morphology of the TM was vastly superior in the semi-thin resin sections than in the thicker paraffin sections. The outer, middle and inner layers were clearly demonstrated. The integrity of the outer epithelial layer was maintained, with an outer keratinizing stratum corneum and underlying stratum granulosum, stratum spinosum and stratum basale layers resting on the basal lamina. The thin inner mucosal layer was also viable, consisting of simple squamous or cuboidal cells. Preservation of the middle lamina propria was achieved, with demonstration of the outer radial and inner circular fibres. CK immunocytochemistry utilizing resin techniques provided excellent staining of CK 7 and 8 in the inner layer, with positive staining of CK 5 and 10 in the outer layer.

Adolescent↗
PubMed2006

Patient's quality of life and hearing outcomes after stapes surgery.

OBJECTIVES: To determine the quality of life (QOL) after stapes surgery and whether audiological parameters for hearing correlate with specific QOL factors. DESIGN: A retrospective cross-sectional study. SETTING: A tertiary referral centre. PARTICIPANTS: A series of 35 patients who underwent stapes surgery of which three were excluded because they were <18 years of age, chronically or mentally ill, or in a dependant relationship. Response rate was 93% (30/32). Nine were further excluded because they had revision or bilateral surgery, or missing data. Twenty-one patients were included in this study. MAIN OUTCOME MEASURES: The Glasgow Benefit Inventory (GBI) was used to evaluate general QOL and the Hearing Disability and Handicap Scale (HDHS) was used as a disease-specific measure. The Belfast Rule of Thumb and Glasgow Benefit Plot assessed hearing outcomes. RESULTS: Operative success was 86% using the Belfast Rule of Thumb and 95% had closure of the air-bone gap to within 20 dB. 81.8% of patients reported a better overall QOL as surgery. Glasgow Benefit Inventory Social and GBI Physical scores correlated positively with the HDHS speech component (P < 0.05). The duration of hearing loss correlated inversely with the average HDHS score (P < 0.05). CONCLUSION: The majority of patients report a better QOL as undergoing stapes surgery. Speech impacts on people's physical and social QOL of patients. Quality of life tools, in addition to objective audiologic measurements can provide clinicians with patients' subjective perspective that helps guide clinical decision-making and counselling.

Activities of Daily Living↗
PubMed2005

Superior canal dehiscence: review of a new condition.

A new cause of sound and pressure induced vertigo, superior canal dehisence, is described. Auditory manifestations include hyperacusis to bone-conducted sounds and conductive hearing loss with normal acoustic reflexes. The diagnosis is reached by a directed history, documentation of upward and torsional nystagmus evoked by sound and pressure, and radiology. Acoustic reflexes and VEMP (vestibular evoked myogenic potentials) aid in the identification of patients with an apparent conductive loss with normal acoustic reflexes or have an asymptomatic dehiscense on radiology. Treatment involves avoidance of the precipitating stimuli. Surgical treatment, by resurfacing the dehiscence, is considered in patients with more severe symptoms.

Acoustic Impedance Tests↗
PubMed2002

Sterile abscess mimicking recurrent tumour in the cerebellopontine angle.

Vestibular schwannomas are the most common tumours encountered in the cerebellopontine angle (CPA) region, accounting for 90 per cent of all lesions. Early pyogenic abscess following surgery and delayed abscesses due to retained foreign bodies have been reported. We describe a case of sterile abscess of unknown aetiology in the CPA region, occurring 13 years after surgical excision of a vestibular schwannoma. The clinical and radiological features were suggestive of recurrent vestibular schwannoma or malignant transformation. We believe this is the first reported case of delayed occurrence of sterile abscess in the CPA region. Further the diagnostic difficulties of such rare lesions occurring in the CPA after vestibular schwannoma surgery are discussed.

Abscess↗
PubMed2000

Evaluating the role of magnetic resonance imaging scans in the surgical management of acoustic neuromas.

OBJECTIVE: To assess the reliability of magnetic resonance imaging (MRI) in predicting the size and position of an acoustic neuroma, with particular reference to the intracanalicular portion. STUDY DESIGN: Prospective study comparing the position of the tumor in the internal auditory canal on fast spin-echo MRI with the actual position measured intraoperatively. METHODS: The study was performed in a tertiary referral neurotology center, encompassing both the public and private health care systems. Fifteen consecutive patients admitted for acoustic neuroma removal via the translabyrinthine approach were studied. The main outcome measure was tumor position in the internal auditory canal expressed in millimeters, accurate to the nearest 0.5 mm. RESULTS: The fast spin-echo MRI was accurate within an error of 1 mm in predicting the lateral extent of the tumor in the internal auditory canal. CONCLUSION: Fast spin-echo MRI can accurately predict the lateral extent of an acoustic neuroma and allow accurate planning of the surgical approach.

Adult↗
PubMed1998

Imaging destructive lesions of the petrous apex.

Cholesterol granuloma and cholesteatoma are the two most common destructive lesions of the petrous apex. Arachnoid cyst is less common. These three expansile lesions are often indistinguishable on clinical grounds. Cholesterol granulomas can be treated effectively through internal drainage into the mastoid cavity or middle ear. Cholesteatomas, however, are managed by more aggressive and complicated removal, which often mandates the sacrifice of hearing. Symptomatic arachnoid cysts are amenable to simple surgical drainage. Therefore, accurate preoperative recognition on computed tomography (CT) and magnetic resonance imaging (MRI) is important in planning proper treatment. Thirteen cases of destructive lesions of the petrous apex are analyzed. The authors' experience illustrates that the "typical" CT and MRI radiographic features are diagnostic in some cases, but not in all. In this study the pathologic findings have been correlated with the radiologic features on both MRI and CT.

Adolescent↗
PubMed1998

The cerebellopontine angle: does the translabyrinthine approach give adequate access?

A long-standing but unfounded criticism of the translabyrinthine approach is the misperception that this approach does not give adequate access to the cerebellopontine angle. Because of what is perceived as limited visualization and operating space within the cerebellopontine angle, some surgeons still believe that the translabyrinthine approach is inappropriate for large acoustic tumors. In this study, the surgical access to the cerebellopontine angle by virtue of the translabyrinthine approach is measured and analyzed. The parameters are compared with those measured for the retrosigmoid approach. This series objectively confirms that the translabyrinthine approach offers the neurotologic surgeon a shorter operative depth to the tumor, via a similar-sized craniotomy. This permits superior visualization by virtue of a wider angle of surgical access. Such access is achieved with the merit of minimal cerebellar retraction.

Cerebellopontine Angle↗
PubMed1998

Meniere's disease: evidence of an immune process.

OBJECTIVE: This study aimed to present further evidence of specific antibodies reactive against bovine inner ear proteins found in patients with Meniere's disease. BACKGROUND: There are a growing number of experimental and clinical features of Meniere's disease that indicate an immune association. Circulating antibodies directed against inner ear proteins have been detected in patients with bilateral progressive hearing loss and Meniere's disease. METHODS: A total of 36 patients with classical Meniere's disease were studied noting the presence of active or inactive, bilateral or unilateral disease. Bovine membranous labyrinth was used as inner ear extract and separated to molecular weights using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Western blotting included the addition of serum buffer (casein, Tween, and bovine serum albumins) and the use of alkaline phosphatase labeled anti-human immunoglobulin antibodies. RESULTS: The findings represent strong evidence of antibodies reactive to inner ear proteins. The incidence of these antibodies was correlated significantly with disease activity. CONCLUSIONS: The findings are further evidence of an immune process that is involved in Meniere's disease.

Adult↗
PubMed1998

Pneumocephalus after acoustic neuroma surgery.

OBJECTIVE: The study was conducted to describe the diagnosis and management of pneumocephalus after acoustic tumor resection. STUDY DESIGN: The study design was a retrospective chart review. SETTING: The study was conducted as a tertiary otologic referral to the senior authors' practices (PAF, MDA). PARTICIPANTS: Three patients operated on for acoustic tumor in St. Vincent's General Hospital and the Scottish Hospital, Sydney, Australia, were studied. INTERVENTION: Observation in both cases and surgery in a case in which tension pneumocephalus was progressive were performed. MAIN OUTCOME MEASURE: Recovery will follow either spontaneously or after intervention. RESULTS: All patients had an uneventful recovery. CONCLUSION: In most cases, spontaneous resolution occurs. However, if surgical re-exploration is indicated, it is best performed via the blind sac subtotal petrosectomy of Fisch.

Aged↗
PubMed1997

Diffuse neurofibroma obstructing the external auditory meatus.

A case is presented of a 36-year-old male with narrowing of the external meatus due to a diffuse neurofibroma. This unusual variety of neurofibroma spreads superficially and has many ecstatic blood vessels. The size, vascularity, uncertain edges and a tendency to recur makes surgical removal difficult. The treatment options are discussed.

Adult↗
PubMed1997

A new technique for hypoglossal-facial nerve repair.

Hypoglossal reinnervation of the facial nerve may be required after a proximal facial nerve injury. The classic hypoglossal-facial graft procedure involves transection of the donor hypoglossal nerve, resulting in hemiglottic paralysis that, in association with paralysis of other cranial nerves, may cause speech and swallowing difficulties. Multiple lower cranial nerve palsies in conjunction with facial paralysis, as may occur after procedures such as skull base surgery, contraindicate the use of such techniques. The successful use of XII-VII "interposition jump grafts" without hemiglossal weakness has been described However, a prolonged recovery period and weaker facial reanimation have been seen. In order to attain maximum facial reinnervation while preserving hypoglossal function, we have developed a new technique of XII-VII repair. This method involves mobilization of the intratemporal portion of the facial nerve remnant, achieving a single anastomosis with the hypoglossal nerve, which has been partially incised. This technique has been used in three patients to date, with 6 to 11 months follow-up. In all cases facial tone and symmetry have been restored and voluntary facial expression accomplished. The authors conclude that by employing the techniques described highly satisfactory cosmetic and functional results may be expected, without compromising hypoglossal nerve function.

Aged↗
PubMed1996

The management of dysphagia in jugular foramen surgery.

From 1985-1994, the Skull Base Unit at St. Vincent's Hospital, Sydney, operated on 61 patients with tumours involving the jugular foramen. Pre-operative assessment by a Speech Pathologist and the institution of swallowing techniques prior to surgery have improved post-operative morbidity. Ancillary procedures at the time of surgery were not required in the majority of cases. An individual assessment of each patient early in the postoperative period was found to be more important with regard to the benefits of supplementary surgery. The majority of patients with dysphagia settled with conservative management and only a few underwent ancillary surgery. It is perceived that the cortical and subcortical control of swallowing is a major factor in the rehabilitation of these patients.

Adolescent↗
PubMed1996

Evolution of the management of hydrocephalus associated with acoustic neuroma.

The management of hydrocephalus in association with a cerebellopontine angle tumor is controversial. There is a widely held belief that initial therapy should always be directed toward treatment of hydrocephalus before definitive surgery. The potential problems of cerebrospinal fluid (CSF) shunting and drainage have to led to an evolution in the management of hydrocephalus at St. Vincent's Hospital. There is growing evidence that complete removal of cerebellopontine angle tumors will result in resolution of hydrocephalus without requiring other methods of CSF decompression. The authors present their experience of 14 patients with hydrocephalus found in a recent series of 104 consecutive cases of acoustic neuroma. This study has detected a significant correlation between hydrocephalus and increasing tumor size (P = .0234). The mean tumor size in this series was 3.8 cm. The series has also demonstrated that successful. safe, and complete tumor removal can be achieved without CSF drainage before surgery.

Adult↗
PubMed1992

Hearing preservation in acoustic neuroma surgery: a continuing study.

Hearing preservation in acoustic neuroma surgery is possible in a limited number of cases. Although there have been many articles published about hearing preservation, there have been few studies of long-term hearing results, nor is it known if there is an increased rate of tumor recurrence when hearing preservation is attempted. Twenty-two patients who underwent a hearing preservation procedure via the retrosigmoid approach were selected from 80 consecutive patients with cerebellopontine angle tumors operated on from February 1984 to November 1987. Useful hearing was retained in 11 cases as reported in a previously published study. Seven patients continue to have useful hearing after 3 to 5 years; 3 have shown a gradual but slight decline. There has been no tumor recurrence in these patients, but 2 patients, operated on early in the series and who had lost hearing, had recurrent tumor.

Auditory Threshold↗
PubMed1992

Petrous apex cholesteatoma: diagnostic and treatment dilemmas.

The diagnosis and treatment of petrous apex cholesteatoma is a difficult surgical challenge. This study is a review of 14 cases of cholesteatoma involving the petrous apex. These cholesteatomas originated as a congenital primary lesion or secondary to an acquired lesion. The cases were evaluated according to the clinical features, the intraoperative findings, the radiological findings, and the surgical approaches. In this series, 83% of the patients presented with hearing loss and 50% presented with facial nerve weakness or paralysis (House grade II to VI). Intraoperative and radiological features revealed frequent direct labyrinthine and supralabyrinthine cell spread. The transpetrous surgical approach was used in all cases. The main factors affecting the surgical approach to be adopted are the inaccessible nature of the petrous apex, the extent of disease, the degree of facial nerve function, and the need for the prevention of cerebrospinal fluid leaks and the recurrence of the lesion.

Adult↗