Otology and audiology in the UK: isolated or integrated practice?
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Audiology↗
Biomedical subjects
D A Moffat
Publications and source records attributed to D A Moffat.
Reproducibility of volume measurements of vestibular schwannomas - a preliminary study.
OBJECTIVE: A preliminary study to investigate the intra-observer and inter-observer variability of measurements of vestibular schwannoma volume using an area-tracing and linear dimension measurement method. DESIGN: Prospective blinded measurements by two observers (one a consultant and one a sub-specialty trainee in neuroradiology). SETTING: Ambulatory patients with known vestibular schwannoma attending a tertiary referral centre. PARTICIPANTS: Twenty-three patients with 26 vestibular schwannomas aged 29-80 years old. MAIN OUTCOME MEASURE: Quantification of the variability in measured volume due to intra- and inter-observer measurement differences, expressed as reliability coefficients within which 95% of repeated measurements are calculated to lie from each other in relative percentage terms. RESULTS: For the linear measurement method, intraobserver variability was calculated to have a reliability coefficient of 65% and for interobserver variability this was 155%. For the area tracing method, the corresponding coefficients were 26% for intraobserver variability and 44% for interobserver variability. CONCLUSIONS: Volume measurements in vestibular schwannoma are variable even when the measurements are made by the same observer on identical images. The area tracing method, commonly regarded as the gold standard, is less variable than a linear method but still introduces more variability than commonly realized (for 95% of patients, repeated measurements by the same observer lie within around 25% of each other). Manual area tracing is not widely used in practice because it is time consuming and reliable automated methods are eagerly awaited.
Adult↗
Team working to improve outcome in vestibular schwannoma surgery.
The concept of the 'learning curve' in the early years of consultant appointment is no longer acceptable and yet, for most complex operations, learning is a career-long process. Sub-specialization offers part of the solution to this problem by concentrating expertise, but there remains the question of how to introduce new team members without adversely affecting patient outcome. Shortened training and an increasingly aware public, who are more questioning of the experience and outcomes of those treating them, has required the surgical profession to move away from individual consultant practice and embrace team-working. When, in 1997, a second neurosurgeon joined the skull base team at Addenbrooke's Hospital, his introduction to acoustic neuroma surgery was mentored and operative cases were carefully selected at first. In this article, we discuss our experience with consultant mentoring, and compare the results of the first 100 translabyrinthine acoustic neuroma operations performed under this system with the first cohort of a similar number of patients published from Cambridge in 1989.
Adolescent↗
Outcome following retrosigmoid microvascular decompression of the facial nerve for hemifacial spasm.
This paper evaluates the outcome of retrosigmoid microvascular decompression of the facial nerve in a series of patients suffering from hemifacial spasm who had been referred to the skull-base team (comprising senior authors DAM and DGH). The paper is a retrospective review of 15 patients who underwent retrosigmoid microvascular decompression of the facial nerve at Addenbrooke's Hospital between 1985 and 1995. In this series it was possible to obtain complete resolution of hemifacial spasm in 93.3 per cent of cases in the short term and in 80 per cent in the long term. Twelve patients (80 per cent) were symptom-free post-operatively. Two patients had minor recurrence of symptoms occurring within six months of the procedure. One patient with no identifiable vascular impingement of the facial nerve had no improvement following surgery. Three patients suffered sensorineural hearing loss. Two patients complained of post-operative tinnitus, and transient facial palsy was noted in one patient. Retrosigmoid microvascular decompression of the facial nerve provides excellent long-term symptom control in a high percentage of patients with hemifacial spasm.
Adult↗
Referral patterns in vestibular schwannomas --10 years on.
Diagnostic imaging techniques, symptom awareness and education of local sources of referral in vestibular schwannomas, including general practitioners, have all improved in the last 10 years. The referral patterns in vestibular schwannomas in Cambridgeshire in the period 1981-1993 has been reported.(1) A direct comparison was made with regard to referral patterns seen in the last 10 years paying particular emphasis to source of referral, diagnosis at referral and symptoms/size at presentation. The incidence of vestibular schwannomas in the region is compared and discussed. Patients' managed by the 'watch and wait' policy were particularly scrutinized, as they were not discussed previously. Retrospective analysis of computerized database was used. We have demonstrated an increase in the proportion of referrals with known vestibular schwannoma to 90% of all referrals. No significant change in length of history prior to referral, source of referral or principal presenting symptom were found. An overall decrease in tumour size was found but an increase in the percentage with larger tumours (>4.5 cm). We attribute the significant findings to an increase in availability of magnetic resonance (MR) scanners in the country during the past 10 years. It appears that some tumours would still present with no symptoms until late and therefore will elude identification until large in spite of a low threshold for MR scanning.
Ear Neoplasms↗
Head-shaking nystagmus in patients with a vestibular schwannoma.
The aim of this study was to calculate the sensitivity of the head-shake test for peripheral and central vestibular dysfunction associated with unilateral sporadic vestibular schwannoma and to discuss the feasibility of using the head-shake test as a screening test. The study group consisted of 102 patients with unilateral sporadic vestibular schwannomas, who were seen consecutively for preoperative vestibular assessment, including the head-shake test. The sensitivity of the head-shake test for vestibular schwannoma was found to be 22%, and the sensitivity and specificity of the head-shake test for canal paresis (>/=25%) were found to be 27% and 88%, respectively. Patients with abnormalities in the central vestibular system and with a greater canal paresis were more likely to have head-shake nystagmus, although, even for severe canal paresis, the sensitivity of the test remained low at 36%. The direction of nystagmus was found to be contra-lateral to the side of the tumour in 86% of patients. It was concluded that the head-shake test is of insufficient sensitivity to be used as a screening test either for vestibular schwannoma or for vestibular-system abnormalities associated with vestibular schwannoma. The deduction is made that the head-shake test is of insufficient sensitivity or specificity to be of clinical value as a screening test for vestibular dysfunction in a general population with symptoms of imbalance.
Chi-Square Distribution↗
A small vestibular schwannoma arising from the inferior vestibular nerve.
The investigation of a complaint of unilateral right sensorineural hearing loss led to the identification of a right 3 mm vestibular schwannoma arising from the inferior division of the right vestibular nerve. On investigation the patient was found to have normal caloric function, this being mediated by the superior vestibular nerve. Both transient and distortion product otoacoustic emissions were absent in the right ear, and ABR was abnormal on this side. These findings are of interest as they indicate that this small lesion produced a hearing loss that was both cochlear and retrocochlear. The anatomical finding that the medial auditory efferents run within the inferior vestibular nerve is considered. This patient did not experience tinnitus or hyperacusis despite the site of the lesion arising from the inferior vestibular nerve.
Gadolinium↗
The effect of vestibular nerve section upon tinnitus.
This paper reviews the published evidence regarding the effect of vestibular nerve section upon tinnitus. This is of relevance not only for those performing and undergoing this procedure, but also for those considering the hypothesis that auditory efferent system dysfunction may be influential in tinnitus perception. The auditory medial efferent fibres within the internal auditory canal run within the inferior vestibular nerve, only joining the cochlear nerve at the anastomosis of Oort, a bundle of 1300 fibres running from the saccular branch of the inferior vestibular nerve to the cochlear nerve. Vestibular nerve section procedures therefore section this efferent olivocochlear pathway, and ablate efferent influence upon that cochlear. If auditory efferent dysfunction is involved in tinnitus perception, this ablation might influence the tinnitus status of that patient. A literature search identified 18 papers mentioning tinnitus status after vestibular nerve section, describing the experiences of a total of 1318 patients. The proportion of patients in whom tinnitus was said to be exacerbated postoperatively ranged from 0% to 60%, with a mean of 16.4% (standard deviation 14.0). The proportion of patients in whom tinnitus was unchanged was 17% to 72% (mean 38.5%, standard deviation 15.6), and in whom tinnitus was said to be improved was 6% to 61% (mean 37.2%, standard deviation 15.2). In the majority of patients undergoing this procedure, ablation of auditory efferent input (and thus total efferent dysfunction) to the cochlea was not associated with an exacerbation of tinnitus. The finding of this review is that efferent dysfunction after vestibular nerve section does not consistently worsen tinnitus.
Humans↗
Eustachian tube function after translabyrinthine vestibular schwannoma surgery.
The objective of this study was to evaluate the short-term and long-term effect of the obliteration of the middle ear and the Eustachian tube on its function and on middle ear anatomy. Forty-two patients who underwent a translabyrinthine removal of a vestibular schwannoma were randomly selected from the 329 patients operated on in the last 5 years. According to the length of follow-up they were divided in two groups. The Eustachian tube was found to open in 40% of cases 8 months (group mean) after the operation and at 4 years in 70% of cases (group mean) after the operation. The mechanisms leading to the opening of the tube are discussed. In addition the absence of long-term middle ear disorders in those with a permanently closed Eustachian tube showed that the presence of atrophied connective tissue and scar tissue in the middle ear prevented the retraction of the tympanic membrane. Obliteration of the Eustachian tube and middle ear is an easy and rapid procedure, which is temporary in most cases and does not increase the risk of long-term middle ear disease.
Adult↗
Schwannomatosis in a child--or early neurofibromatosis type 2.
A case of multiple cervical schwannomas in a five-year-old boy, without other evidence of neurofibromatosis type 2, is described. Schwannomatosis is a disorder characterized by the presence of multiple schwannomas in the absence of neurofibromatosis type 2 that has only been recognized in the last 15 years. The clinical and genetic features of neurofibromatosis types 1 and 2 and schwannomatosis are compared and contrasted. This patient with possible schwannomatosis is presented to illustrate the potential pitfalls of making this diagnosis in the paediatric age group and to increase awareness of the debate on whether this is a distinct entity or a form fruste of neurofibromatosis type 2.
Child, Preschool↗
Meningioma in the internal auditory canal.
A case is presented of an entirely intracanalicular meningioma in a 48-year-old woman that was excised via a conventional translabyrinthine approach to the internal auditory canal (IAC). Pre-operative magnetic resonance imaging (MRI) suggested that the tumour was a vestibular schwannoma (VS). Histological examination confirmed the intra-operative impression that the tumour was a meningioma. Although VS is by far the commonest intracanalicular tumour, the differential diagnosis includes meningioma. MRI is unable to distinguish between these two entities when the tumour is located entirely in the internal auditory canal.
Ear Canal↗
An experimental investigation of the resolution of tympanometry for micro-perforations of the tympanic membrane.
Tympanometry is well established as a useful tool in the field of otological diagnosis. There have been sporadic reports, however, of bizarre tympanograms in the presence of small perforations of the tympanic membrane. A model of the outer and middle ears was fabricated which was able to produce normal and pathological tympanograms. This model was used to investigate tympanometry in the presence of microperforations. A hypothesis for the mechanism of generation of sawtooth tympanograms in the presence of micro-perforations is postulated.
Acoustic Impedance Tests↗
Magnetic resonance imaging results in patients with central electronystagmography findings.
The objective of this study was to determine the findings on magnetic resonance imaging (MRI) in patients identified as having central vestibular abnormalities on electronystagmography (ENG) testing, to discuss the issue of 'gold standard' in the investigation of central oculo-vestibular system diseases and to present a model for understanding this area. A retrospective review of the case notes of patients (n = 23) found to have central ENG findings at vestibular assessment and for whom MRI scanning data was available was undertaken. Each patient underwent a full ENG evaluation, including gaze, ocular-motor and caloric testing, and MRI. Only seven of the patients with central ENG findings had abnormal MRI scans. Thus, the incidence of the identification of structural abnormality on MRI in patients with central ENG findings is low. These investigations are complementary in the investigation of balance disorder patients.
Brain↗
A study of perioperative lumbar cerebrospinal fluid pressure in patients undergoing acoustic neuroma surgery.
The objective of this study was to measure changes in cerebrospinal fluid (CSF) pressure and cerebrovascular hemodynamics following acoustic neuroma surgery. The subjects were 32 patients undergoing translabyrinthine or retrosigmoid excision of acoustic neuroma. CSF pressure and the amplitude of the CSF pressure pulse wave were measured using lumbar catheters, and all variables were recorded minute by minute on a microcomputer. Transcranial doppler (TCD) was used to measure flow velocity in the middle cerebral artery in 10 patients to monitor changes in cerebral hemodynamics. In the 24 hours after surgery, all patients showed a statistically significant rise in CSF pressure from 11.4 mm Hg (standard deviation [SD] 6.1) to 19.6 mm Hg (SD 5.2) and a corresponding fall in the compliance of the CSF compartment. These changes were reversed within 48 hours, and the CSF pressure fell below the preoperative level over the next 4 days without any drainage of CSF. The results of this study demonstrate a transient increase in CSF pressure and decrease in craniospinal compliance that is provoked by surgery. The most plausible explanation for this disturbance is impaired CSF absorption, which resolves rapidly in most patients without therapeutic CSF drainage.
Journal Article↗
Clinical presentation of a group of NF2 patients to a tertiary referral skull base unit.
The objective of the investigation was to document the clinical presentations of a group of patients with neurofibromatosis type two syndrome (NF2), and took the form of a retrospective case note review. The investigation took place in the tertiary referral skull base unit. The dominant presentation of patients with NF2 is with auditory/vestibular symptoms (56%), with a smaller proportion of presentations being due to non-acoustic intracranial and spinal tumours (44%). At the time of presentation the majority of clinically significant tumours could be demonstrated in each patient with MRI of the head and spine, with few new tumours arising during the subsequent follow-up period. The range of presentation of patients with NF2 results in their management being fragmented into a variety of clinical setting, diluting the experience amassed in any one centre.
Adolescent↗
Rupture of an internal carotid artery aneurysm in the petrous temporal bone.
A case of otorrhagia following the rupture of an aneurysm of the intrapetrous portion of the internal carotid artery is presented. The aneurysm was successfully treated by balloon occlusion of the parent artery. The problems associated with diagnosis and clinical management of these lesions is discussed and possible solutions suggested.
Adult↗
Postoperative quality of life in vestibular schwannoma patients measured by the SF36 Health Questionnaire.
OBJECTIVE: To quantify the postoperative quality of life in patients following surgical treatment for vestibular schwannoma. STUDY DESIGN: Patient self-assessment using the short form 36 (SF36) multidimensional quality of life health questionnaire. Sex- and age-matched normalized scores were calculated using a standardized process and accepted normative data. SETTING: Tertiary referral skull base unit. RESULTS: An 80% response rate (90 patients) was achieved. The postoperative quality of life in vestibular schwannoma patients, as quantified by seven of the eight SF36 health scales was less than the appropriate matched healthy standard. Comparison of a variety of preoperative patients and tumor factors-different operative approaches (translabyrinthine and retrosigmoid), tumor size (group cut of points of tumor diameter 1.5 mm and 2.5 mm), patient sex, and ranking of patient age-showed no statistically significant difference in measured quality of life outcomes for each of these traditional predictors. CONCLUSION: Reduced quality of life in patients after surgical treatment for vestibular schwannoma, coupled with the low tumor growth rates and minimal preoperative symptoms, supports a conservative approach to patient management. The advantages and disadvantages of a variety of approaches used to measure the quality of life after surgical treatment of vestibular schwannoma and their impact on clinical decision making for patients, are discussed.
Adult↗
Glomus jugulare tumour with metastases to cervical lymph nodes.
Glomus jugulare tumours are classically described as benign tumours with a long time course often measured in decades. Although these tumours may be locally invasive, most cases are histologically benign and metastases are rare. The case of a malignant glomus jugulare tumour with a particularly aggressive pattern of spread is presented. At the time of surgery, which was within 12 months of the development of symptoms, intracranial spread and metastasis to cervical lymph nodes had already occurred, demonstrating that glomus jugulare tumours are not always benign.
Adult↗