Biomedical subjects

D A Moffat

Publications and source records attributed to D A Moffat.

At least 91 records · Page 5Linked to original sources

PubMed1992

Bilateral optic nerve sheath meningiomas in a patient with neurofibromatosis type 2.

A 34-year-old woman who presented with hearing loss and tinnitus was found to have reduced vision bilaterally. Computed tomography scan revealed bilateral acoustic neuromas and bilateral optic nerve sheath meningiomas. The presence of bilateral acoustic neuromas fulfils the criteria for the diagnosis of central neurofibromatosis (neurofibromatosis type 2). Although this is the first report of bilateral optic nerve sheath meningioma in neurofibromatosis type 2, meningiomas are commoner in this dominantly inherited disorder, than in its absence and both forms of central nervous system tumour may be caused by loss of tumour suppressor genes on chromosome 22.

Adult↗

PubMed1992

Bilateral electrocochleographic findings in unilateral Menière's disease.

At present, electrocochleography is the only proven investigation that can demonstrate objectively the presence of endolymphatic hydrops. The electrophysiologic recordings in response to sound stimuli show an enhancement of the negative summating potential in these cases. It is well established that patients with unilateral Meniere's disease have a high likelihood of development of the disease bilaterally in the fullness of time. Using transtympanic electrocochleography in 40 patients who manifested unilateral clinical Meniere's disease, we have recorded bilateral abnormalities indicative of endolymphatic hydrops in 35% of cases. The early recognition of incipient Meniere's disease in the asymptomatic contralateral ear of a patient with known unilateral disease has obvious profound implications for patient management.

Action Potentials↗

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↗

PubMed1991

Bilateral acoustic schwannoma: post-operative hearing in the contralateral ear.

A patient with neurofibromatosis two (NF2) presented with bilateral acoustic neuroma. Pre-operative audiometry revealed a dead right ear and severe left-sided sensorineural hearing loss. Following surgical removal of the larger right acoustic neuroma we have documented a sensorineural improvement of 45 dB in the contralateral ear on pure tone audiometry, which as far as the authors are aware has not previously been described.

Adult↗

PubMed1991

Posterior fossa vestibular neurectomy.

Many procedures have been devised to deal with intractable vertigo and conserve hearing, but despite this selective vestibular nerve section remains by far the most effective treatment. A series of 14 patients who underwent posterior fossa vestibular neurectomy is reported. The results are reported for vertigo control, hearing and tinnitus. All of the patients achieved vertigo control according to the AAOO (1972) reporting system. A simple and reliable system for the classification of the disability in these patients has yet to be devised. This problem is addressed and a disability grading system proposed, and discussed.

Disability Evaluation↗

PubMed1991

Persisting incidence and mortality of sinogenic cerebral abscess: a continuing reflection of late clinical diagnosis.

Seventy-four verified cases of cerebral abscess seen in the Regional Neurosurgical Centre at Addenbrookes Hospital, Cambridge between 1965 and 1987 were reviewed. During that time no decline in incidence or change in the associated mortality was found to occur. ENT disease, taken as a whole, represented the most common source (40%) while acute frontal sinusitis (23%) proved to be the most common single underlying cause. Cerebral abscesses of sinogenic origin in particular were diagnosed late, with a deteriorating conscious level being the precipitating event in 94% of cases. Over 80% of such patients had presented initially to a non-ENT department with acute frontal headache where neither the underlying frontal sinusitis nor the developing intracranial complication had been suspected. These findings might explain why the incidence and mortality associated with cerebral abscesses of sinogenic origin, have changed little in the last 25 years despite improvements in diagnostic imaging, surgical technique and antibiotic therapy. We recommend that the diagnosis of acute frontal sinusitis be considered in any patient who presents with acute frontal headache, particularly if symptoms are unilateral. Furthermore, we stress that early confirmation of intracerebral complications by computerized axial tomography (CT) scanning continues to depend entirely upon an early clinical diagnosis which should result from a high level of clinical suspicion in patients who develop intracranial symptoms in the presence of known acute frontal sinus infection.

Adolescent↗

PubMed1990

Endolymphatic hydrops precipitated by haemodialysis.

We report a case of endolymphatic hydrops preceded by haemodialysis in the contralateral ear of a patient with known Menière's disease, and discuss the possible mechanism. It is suggested that the sudden decrease of plasma osmolality during haemodialysis acts as a reverse glycerol test. The audiometric and electrophysiological recordings pre- and post-dialysis and the induction of the Menière's triad of symptoms during dialysis, were strongly indicative of the presence of endolymphatic hydrops.

Aged↗

PubMed1989

Strategy and benefits of acoustic neuroma searching.

Advances in audiological, radiological and microsurgical techniques have enabled otologists to diagnose and excise very small acoustic tumours with a low morbidity and mortality. Is this cost effective? In an attempt to answer this question, an analysis of 66 cases of surgically treated acoustic neuromas is presented. This represents part of a series of skull base procedures carried out at Addenbrooke's Hospital over the last five years. As a result of this work an investigative protocol is suggested. By studying the relative morbidity of early and late surgical intervention in these cases, and by costing the exercise, the justification for early diagnosis and treatment is presented both in financial and human terms.

Adult↗

PubMed1989

Role of post-operative electroneuronography in predicting facial nerve recovery after acoustic neuroma removal: a pilot study.

Complete clinical facial paralysis immediately after acoustic neuroma removal occurs in between 40 to 90 per cent of patients despite the fact that the facial nerve has been preserved anatomically. Some of these patients improve rapidly with adequate cosmetic and functional recovery. Others however, have incomplete or no return of useful function. A pilot study to assess the prognostic value of electroneuronography (ENOG) in 14 patients following acoustic neuroma removal was performed. The results suggest that post operative ENOG is of value in dividing those patients with anatomically intact facial nerves yet complete clinical paralysis post-operatively into groups: one with rapid improvement to an acceptable functional and cosmetic result and one with prolonged paralysis with incomplete or no recovery. Electroneuronography may thus be used to predict the initial recovery profile in patients with complete facial paralysis after surgery.

Adult↗

PubMed1989

Facial nerve recovery after acoustic neuroma removal.

A retrospective analysis of 76 patients who underwent acoustic neuroma removal is reported. Facial nerve function prior to surgery and tumour size are assessed with respect to final facial nerve recovery and the need for surgical rehabilitation. Both pre-operative facial weakness and tumour size greater than 2.5 cm. are shown to be predictive factors of poor facial nerve recovery. Multiple surgical rehabilitative procedures are often required when inadequate function and/or cosmetic results are obtained. Primary nerve repair and facial-hypoglossal anastomosis give better rehabilitative results than dynamic and static procedures. The association of tumour size greater than 2.5 cm. with increased risk of poor facial recovery re-emphasizes the need to detect and remove acoustic neuromas at an early stage.

Adolescent↗

PubMed1989

Benign paroxysmal positional vertigo resulting from surgical trauma.

A patient developed benign paroxysmal positional vertigo following partial excision of the upper jaw for squamous carcinoma. It is probable that the trauma sustained by the labyrinth during surgery led to the development of vertigo. Benign paroxysmal positional vertigo may be a preventable post-operative complication.

Aged↗

PubMed1989

Aberrant reinervation of the stapedius muscle following facial palsy.

This case report describes the clinical course of a patient with Ramsay Hunt Syndrome. Partial recovery of the lower motor neuron facial palsy was associated with decreased hearing and a reduction of the middle ear compliance on voluntary contraction of the facial musculature. It is suggested that this is due to misdirection of regenerating nerve fibres, normally destined for facial muscles, to stapedius muscle.

Adult↗

PubMed1989

Contralateral auditory brainstem response abnormalities in acoustic neuroma.

Contralateral Auditory Brainstem Response (ABR) findings in a series of 79 patients with unilateral acoustic neuroma are presented. Sixty-four patients (81 per cent) had a normal contralateral ABR, thirteen (16.4 per cent) had latency abnormalities contralaterally and in two patients (2.6 per cent) no consistent responses could be recorded despite good hearing. Abnormalities in the contralateral ABR were analysed and five patients had abnormal III-V interwave intervals, in seven patients the I-III intervals were abnormal and in one patient, only the fifth wave was present and of abnormal latency. The tumour size was assessed by computed axial tomography (CT) and the relationship between tumour size and contralateral ABR findings established. Large tumours (greater than 2.5 cm.) were associated with contralateral ABR abnormalities in 25.6 per cent of the patients, medium tumours (1.0-2.5 cm.) with ABR abnormalities in 14 per cent and there were no abnormalities in the small group (intracanalicular). The implications for interpretation of ABR recordings contralateral to an acoustic neuroma are discussed in relation to brainstem compression and its effect on the wave generator sites.

Brain Stem↗

PubMed1989

Hearing aids--a case for review.

An analysis of a series of 100 patients aged 60 years or over, referred by their General Practitioner to the Department of Otolaryngology, Addenbrooke's Hospital, specifically for the provision of a hearing aid, is presented. Forty-six per cent of patients failed to satisfy the criteria suggested by the Technicians, Therapists and Scientists in Audiology as a screening for treatable pathology. This study has shown that the existing referral pattern of general practitioner to consultant otolaryngologist for the provision of a hearing aid reflects the highest quality of care for the patient. Direct referral or open access of patients for hearing aid fitting may risk failure to diagnose early and treatable conditions.

Aged↗

PubMed1989

Mastoid ache in acoustic neuroma.

In a series of 100 patients with unilateral acoustic neuroma the incidence of mastoid aching was found to be 25 per cent, though none of the patients reported this as their principal symptom. Mastoid ache was not related to tumour size, hydrocephalus, or duration of symptoms. However, there was a significantly higher incidence of facial numbness and diminished facial sensation, but not facial weakness, compared with the whole series. Since motor fibres are more resistant to pressure than sensory fibres, mastoid ache may signify the pressure of an expanding cerebellopontine angle tumour.

Face↗

PubMed1989

Reliability of the House and Brackmann grading system for facial palsy.

The House and Brackmann grading system has been recommended as a universal standard for assessing the degree of facial palsy. This study examined the inter-observer reliability of this system. Three observers assigned a grade to each patient, examined independently, on the same day. Forty patients with a unilateral facial palsy of varying aetiology and severity were assessed. Of the 120 judgements, eight were in dispute, by a maximum of one grade, giving an inter-observer reliability of 93 per cent. We conclude that the House and Brackmann grading system is a simple and robust method of assessing facial function.

Adolescent↗

PubMed1989

Surgical management of large glomus jugulare tumours: infra- and trans-temporal approach.

Surgery may have to be considered in the management of large glomus tumours since other modalities of treatment are not curative. The judicious use of surgical intervention is imperative since a neurological deficit involving the last four cranial nerves may ensue and consideration of the quality of life of the patient in the post-operative period is of paramount importance. A brief description of the historical aspects and pathology of these tumours is followed by an analysis of the clinical presentation, investigation and assessment of a series of 10 patients. Six patients underwent surgery and their tumours were removed by the infra- and trans-temporal approach. This is described and illustrated in detail and the surgical results presented.

Adult↗

PubMed1989

Early diagnosis and surgical management of acoustic neuroma: is it cost effective?

Audiological and radiological advances and refinement of microsurgical techniques have facilitated the diagnosis and excision of very small acoustic nerve tumours with a low morbidity and mortality. Is this cost effective? In an attempt to answer this question, an analysis of 66 cases of surgically treated acoustic neuromas is presented. This represents a part of a series of otoneurosurgical procedures carried out at Addenbrooke's Hospital over the last five years. By studying the relative morbidity of early and late surgical intervention in these cases, and by costing the exercise, the justification for early diagnosis and treatment is presented both in financial and human terms.

Adult↗