Factors affecting final facial nerve outcome following vestibular schwannoma surgery.

OBJECTIVE: To determine factors affecting facial nerve outcome of vestibular schwannoma surgery. METHODS: This retrospective cohort study comprised 652 patients. The outcome measure was House-Brackmann classification at two years post-operatively. Univariate and multivariate analyses were carried out to determine the factors affecting facial nerve outcome. The incidence rates of hemifacial spasm, metallic taste and crocodile tear syndrome were recorded. RESULTS: For tumours less than 1.5 cm, 95 per cent of outcomes were normal, 100 per cent were satisfactory (House-Brackmann grades I-III) and 0 per cent were unsatisfactory (grades IV-VI). For tumours 1.5-2.4 cm, 83 per cent of outcomes were normal, 99 per cent were satisfactory and 1 per cent were unsatisfactory. For tumours 2.5-3.4 cm, 68 per cent of outcomes were normal, 96 per cent were satisfactory and 4 per cent were unsatisfactory. For tumours 3.5-4.4 cm, 52 per cent of outcomes were normal, 80 per cent were satisfactory and 20 per cent were unsatisfactory. For tumours larger than 4.4 cm, 50 per cent of outcomes were normal, 72 per cent were satisfactory and 28 per cent were unsatisfactory. CONCLUSION: Tumour size and operation year were significant predictors of facial nerve outcome. The surgical learning curve was steepest for the first 50 patients.

Outcome of translabyrinthine surgery for vestibular schwannoma in neurofibromatosis type 2.

OBJECTIVES: To analyse the long-term outcome of translabyrinthine surgery for vestibular schwannoma (VS) in neurofibromatosis type 2 (NF2). RESEARCH TYPE: Retrospective cohort study. SETTING: Two tertiary referral NF2 units. PATIENTS: One hundred and forty eight translabyrinthine operations for patients with VS were performed. Preoperative stereotactic radiotherapy had been performed on 12(9.4%) patients. RESULTS: Mean tumour size was 3.1 cm. Total tumour excision was achieved in 66% of cases, capsular remnants were left in 24% of cases, and subtotal excision was achieved in 5% and partial removal was achieved in 5%. The radiological residual/recurrence rate was 13.9%. The perioperative mortality was 1.6%. At 2 years postoperatively, facial function was expressed in terms of House-Brackmann score (HB): HB 1 in 53.4%, HB 1/2 in 61.3%, HB 1-3 in 83.2% and HB 4-6 in 16.8%. All nine patients who underwent surgery following failed stereotactic radiotherapy had HB 3 function or better. Among 9.5% of the cases, 14 facial nerves were lost during surgery and repaired using direct anastomosis or grafting. There was no tinnitus present preoperatively in 27% of the cases, and 22% of patients developed tinnitus postoperatively. In patients with preoperative tinnitus, 61% remained the same, 17% got it resolved and only in 21% it worsened. The preoperative hydrocephalus rate was 26%, and among 15% of the cases five ventriculo-peritoneal (VP) shunts were performed. The cerebrospinal fluid leak rate was 2.5%. Fifty-six patients underwent auditory brainstem implantation (ABI) and two patients had cochlear implant (CI) sleepers inserted. CONCLUSIONS: The management of patients with NF2 presents the clinician with a formidable challenge with many patients still presenting themselves late with the neurological compromise and a large tumour load. There is still an argument for the management by observation until the neurological compromise dictates interventional treatment particularly with the option of hearing rehabilitation with ABI or CI. The translabyrinthine approach provides a very satisfactory means of reducing the overall tumour volume.

Immunoglobulin G4 related systemic sclerosing disease involving the temporal bone.

OBJECTIVE: To report a rare condition affecting the temporal bone. Immunoglobulin G4 related systemic sclerosing disease is a recently described autoimmune condition with manifestations typically involving the pancreas, biliary system, salivary glands, lungs, kidneys and prostate. Histologically, it is characterised by T-cell infiltration, fibrosis and numerous immunoglobulin G4-positive plasma cells. This condition previously fell under the umbrella diagnosis of inflammatory pseudotumour and inflammatory myofibroblastic tumour. CASE REPORT: We present the case of a 58-year-old woman with multiple inflammatory masses involving the pharynx, gall bladder, lungs, pelvis, omentum, eyes and left temporal bone, over a seven-year period. We describe this patient's unusual clinical course and pathological features, which resulted in a change of diagnosis from metastatic inflammatory myofibroblastic tumour to immunoglobulin G4 related systemic sclerosing disease. We also review the literature regarding the management of inflammatory pseudotumours of the temporal bone, and how this differs from the management of immunoglobulin G4 related systemic sclerosing disease. CONCLUSION: We would recommend a full review of all histological specimens in patients with a diagnosis of temporal bone inflammatory pseudotumour or inflammatory myofibroblastic tumour. Consideration should be given to immunohistochemical analysis for anaplastic lymphoma kinase and immunoglobulin G4, with measurement of serum levels of the latter. Management of the condition is medical, with corticosteroids and immunosuppression, rather than surgical excision.

A critical evaluation of the evidence on a causal relationship between Helicobacter pylori and otitis media with effusion.

OBJECTIVE: There is growing interest in the presence of Helicobacter pylori in the upper aerodigestive tract, and in the middle ear in patients with otitis media with effusion. Some studies have reported detecting H pylori in the middle ear, although reports to the contrary exist. In this study, we critically evaluate the evidence for the theory that H pylori in the middle ear plays a role in otitis media with effusion. MATERIAL: We undertook a systematic review of all available studies investigating the presence of H pylori in the middle ear of patients with otitis media with effusion. The current literature was critically analysed using the key words and phrases 'Helicobacter pylori' 'otitis media with effusion', 'serous otitis media', 'glue ear' and 'middle ear'. Six original research papers were identified, studying a total of 203 patients and 27 controls; two of these papers were randomised, controlled studies and four were prospective, cohort studies. RESULTS: At present, there is poor evidence for the existence of H pylori-associated otitis media with effusion. CONCLUSIONS: Further research in the field is needed in order to delineate the presence of H pylori and its role in the pathogenesis of otitis media with effusion.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

An investigation of the audiologic handicap associated with unilateral sudden sensorineural hearing loss.

OBJECTIVE: To determine the incidence of tinnitus and associated handicap after unilateral sudden sensorineural hearing loss (SSNHL); in addition, to determine the hearing handicap experienced as a consequence of such a loss. STUDY DESIGN: Identification of patients and determination of demographic and audiologic data by retrospective case review; determination of handicap and distress by postal questionnaire. SETTING: Teaching hospital department of otolaryngology. PATIENTS: Thirty-eight patients were identified as having been treated for a unilateral sudden sensorineural hearing loss in the period 1988 through 1997. Of those, 21 (55.3%) replied to the questionnaire. MAIN OUTCOME MEASURES: Audiometric data at admission and at 4-week follow-up, Tinnitus Handicap Inventory (THI), visual analogue scales of tinnitus loudness and distress, Hearing Handicap Inventory in Adults (HHIA). RESULTS: The questionnaire responder group did not significantly differ from the questionnaire nonresponder group on demographic nor audiometric variables, and hence were considered to be a representative sample. Tinnitus was present in 14 patients (67%). Hearing handicap was found in 86% of patients (of the 21 questionnaire responders) and tinnitus handicap in 57% (of the 14 with tinnitus). Correlations were found between tinnitus loudness, distress, and handicap. There was no correlation between time elapsed since SSNHL and tinnitus or hearing handicap, nor was there a correlation between the extent of audiometric loss and hearing or tinnitus handicap. A strong negative correlation was, however, found between recovery in audiometry in the first 4 weeks after onset and tinnitus and hearing handicap. The audiometric status of the contralateral ear correlated with hearing handicap. CONCLUSIONS: A majority of patients after unilateral SSNHL have a perceived handicap associated with tinnitus and hearing. Although this condition is an otologic emergency, careful thought should be given to the audiologic rehabilitation of this patient group.

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.

Cavernous haemangioma of the internal auditory canal.

Cavernous haemangiomas are rare lesions of the cerebello-pontine angle that can mimic the more commonly occurring vestibular schwannoma. A case report involving a patient with a cavernous haemangioma of the internal auditory canal (IAC) highlights this as a diagnostic possibility for lesions of the IAC by comparing and contrasting the clinical and radiological findings with the more commonly occurring vestibular nerve and facial schwannomas. Symptoms such as hearing loss and facial paralysis that are disproportionate to the size of the lesion or fluctuate with hormonal changes such as those seen in pregnancy are suggestive of haemangioma. Radiological imaging demonstrating a lesion enhancing with gadolinium and containing areas of calcification is also suggestive of haemangioma. It is important to consider the possible diagnosis of haemangioma as early recognition of this entity may improve the chances of preserving the functional integrity of the facial nerve.

Positional vertigo as a first symptom of a cerebellopontine angle cholesteatoma: case report.

We report a case of a cerebellopontine angle cholesteatoma whose initial sign was benign paroxysmal positional vertigo (BPPV). Positional vertigo caused by a central pathology is extremely rare and is usually accompanied by other suspicious features. In this case, there were no additional neurotologic symptoms or signs. The only abnormalities were seen on Dix-Hallpike testing, but because they were not consistent with a diagnosis of BPPV, the decision was made to proceed to imaging. Diagnostic rigor is required when evaluating positional vertigo, as with all symptoms of imbalance, if such cases are not to be overlooked.