Biomedical subjects
Publications and source records attributed to G B Brookes.
An auctioneer is described in whom focal dystonia of the jaw developed as an occupational symptom, occurring solely and predictably when he commenced his selling "patter" and resolving quickly on stopping. He responded well to treatment with intramuscular botulinus toxin.
Eight patients with a chondrosarcoma of the temporal bone have been treated at the National Hospital for Neurology and Neurosurgery over a 16-year-period. Patients usually presented with symptoms and signs of lower cranial nerve palsies, though in most cases these resolved after surgery. This result, combined with the fact long-term survival can be achieved, makes surgical treatment of these tumours the best option, as the response to primary radiotherapy is uncertain. Surgical access is difficult, but an infratemporal approach is probably the most satisfactory. The use of post-operative adjuvant radiotherapy may provide some benefit. Long-term follow-up is necessary, and for this magnetic resonance imaging (MRI) is preferable to computed tomography (CT) scanning.
The Glasgow benefit plot has encouraged surgeons to look at the results of their surgery from a more functional standpoint rather than in purely technical terms. Our aim was to use the plot to examine the efficacy of second side stapedectomy. A retrospective study of 17 second side stapedectomies showed that the addition of the second operation significantly increased the chances of achieving at least one 'normal' hearing ear and made 'normal' and symmetrical hearing possible.
Evoked otoacoustic emissions (EOAE) are active mechanical responses from the cochlea which provide information about the integrity of the preneural cochlear receptor mechanisms. It may be hypothesised, therefore, that if a hearing impairment is neural in origin, normal EOAEs may be obtained from the cochlea, which, although dissociated, is functioning normally. This study examined the status of the cochlea with EOAE in patients with cochlear (Meniere's disease) and neural (surgically proven acoustic neuroma) disease. In patients with presumed cochlear lesions, no emissions were present with mean hearing worse than 40 dB across a frequency range of 0.5 to 4 kHz. Similarly, an EOAE was not present in any of the 26 acoustic neuroma patients studied when the average (0.5 to 4 kHz) hearing was greater than 40 dB. We conclude that dissociation of the cochlea in patients with acoustic neuroma appears to be rare and, in fact, cochlear involvement occurs in most cases. Possible mechanisms responsible for the effect on the cochlea in this group include degenerative changes due to chronic partial obstruction of the blood supply by the tumour, biochemical alterations in the inner ear fluids, loss of efferent control of active mechanical tuning, and hair cell degeneration secondary to neuronal loss in the eighth nerve.
Aspergillosis of the paranasal sinuses is a well-established clinical entity which has recently been classified into non-invasive and invasive forms with distinct sub-divisions of both types. Two cases are described, both highlighting potential serious complications of the disease as well as the importance of adequate medical and surgical treatment in effecting a favourable outcome. The disease is reviewed and the question as to whether cases necessarily fall into previously-defined clinical and pathological categories is also discussed.
Loss of bony integrity of the temporomandibular joint may result in prolapse of the joint capsule into the external auditory canal. This in turn gives rise to arthralgia, trismus and earache and a risk of septic arthritis. We describe a technique of repair which is simple, uses autologous tissue and has an acceptable cosmetic and functional result.
Subtotal petrosectomy with external canal overclosure has been used in the management of 10 patients with chronic suppurative otitis media in the past four years. These patients fall into two categories. One group consisted of patients with end-stage chronically discharging mastoid cavities, despite aggressive medical therapy. The other group comprised patients who had developed disabling peripheral vestibular symptoms and had a mastoid cavity from past surgery for chronic otitis media. In both groups the affected ear had absent or poor auditory function. In the second group, a translabyrinthine section of the vestibular and/or cochlear nerves was performed in conjunction with subtotal petrosectomy. The procedure has been very successful in relieving the persistent otorrhoea, giving the patient an ear without a cavity that would need regular care. No restriction on swimming and participation in other water sports is an additional advantage. Illustrative cases are used to discuss the technique and indications.
Tinnitus produced by synchronous repetitive contraction of the middle ear muscles (middle ear myoclonus) is a rare condition. We present six cases of middle ear myoclonus in whom different management regimes were successful. In two patients, the tinnitus was controlled by conservative measures. In one patient, whose tinnitus was associated with blepharospasm, significant improvement occurred following botulinum toxin injection into the ipsilateral orbicularis oculi. Three patients were cured by tympanotomy with stapedial and tensor tympani tendon section. The aetiology of this type of myoclonus remains unclear. The diagnosis is based on the history of involuntary and rhythmic clicking or buzzing tinnitus which is invariably unilateral. The primary differential diagnosis is palatal myoclonus whilst other local aural pathologies must be excluded by careful clinical assessment. Surgical section of these muscles via tympanotomy brings guaranteed relief when conservative measures fail.
Mucoceles are uncommon and the majority occur in the fronto-ethmoidal complex. We present the first case of a secondarily infected mucocele arising from a concha bullosa of the middle turbinate. It was excised intranasally with complete resolution of symptoms.
Hearing conservation in acoustic tumour surgery remains controversial. There have been few previous reports in the British literature. The senior author has managed 24 patients by retrosigmoid surgery with the intention of preserving hearing during the last 9 years. The clinical features, surgical technique and results are discussed with respect to pre-operative selection criteria, and post-operative quality of hearing. Hearing preservation has been achieved in 11 (78.6%) of 14 patients with small or intracanalicular tumours and a mean minimum auditory threshold of 35 dB and 70% speech discrimination, the majority (81.8%) above the 50 dB/50% level. Tumour filing the fundus of the internal auditory canal was found to be a significant adverse prognostic factor as regards successful hearing preservation. Tumour excision was complete in all patients. Nearly 90% of patients had normal facial function, and the remaining 10% grade II function. Associated morbidity was minimal. It is suggested that the potential for hearing conservation should be considered as a factor in the management of patients with small acoustic neuromas.
The effects of contralateral acoustic stimulation on evoked otoacoustic emissions (OAE) were examined in three subject groups in order that the impact of efferent olivocochlear bundle section (as a consequence of vestibular neurectomy) could be compared with normal findings, and with a control surgical population. Results demonstrated that the inhibitory effect of contralateral noise on OAE amplitude was absent from the cochlea with severed efferent fibers. These findings appear to be independent of acoustic reflex activity, as suppression was absent despite normal reflexes. Inter-aural suppression of emissions recorded from the patients' intact cochleae act as a control and show a clear reduction in amplitude during contralateral stimulation in a frequency specific pattern consistent with normal findings. Patients who had undergone a similar surgical approach for vascular decompression of the VIIIth nerve without vestibular nerve section, were studied in order to assess the impact of retrolabyrinthine surgery on inter-aural suppression. Inhibition of OAE amplitude was maintained in all control cases in both the operated and intact sides, and was consistent with suppression observed in normal subjects, suggesting that the surgical procedures had not disturbed inter-aural suppression of otoacoustic emissions. It is concluded that the olivocochlear efferent system, when activated by low level contralateral acoustic stimulation, has an inhibitory role in controlling the cellular mechanisms responsible for the generation of otoacoustic emissions in humans. OAE techniques in conjunction with contralateral acoustic stimulation may thus prove to be of value in providing a rapid and non-invasive clinical test of efferent function and offer a means of investigating the functional significance of the efferent auditory system in humans.
Patients undergoing vestibular nerve section for vertigo or acoustic neuroma surgery were compared pre- and post-operatively and during long-term follow-up using a range of tests including: nystagmography, impulsive rotational testing of the vestibulo-ocular reflex (VOR), ability to estimate and reproduce imposed rotational displacements, validated questionnaires rating vertigo, imbalance, autonomic reactivity and somatisation, and clinical and self-assessment scales of overall outcome in terms of symptoms and disability. Correlations were found between rating scale assessments, questionnaire scores and estimates of self-rotation. Neither nystagmography nor VOR tests correlated with the presence or severity of vertigo or imbalance. Post-operatively, vertigo patients reported that they had received significant relief, although they had higher incidences of residual complaints of imbalance and vertigo than patients after acoustic neuroma surgery. Factors impeding rehabilitation in patients with vertigo are discussed.
Severe secretomotor (vasomotor) rhinopathy is a very uncommon nasal condition which is believed to result from marked autonomic neural imbalance to the nasal and lacrimal glands. It has not, to our knowledge, been reported after trauma or elective surgery. A patient is described who developed this condition after a Le Fort maxillary osteotomy. The clinical difficulties of establishing this diagnosis are highlighted, and contemporary management options are discussed.
This study demonstrates that, following unilateral vestibular neurectomy, the inhibitory effect of contralateral acoustic stimulation on evoked otoacoustic emissions is absent. The patient acts as her own control in that the unoperated side shows normal suppression of otoacoustic emission amplitude with contralateral acoustic stimulation. The lack of interaural suppression of otoacoustic emissions on the sectioned side, in the presence of normal acoustic reflex threshold levels, provides evidence that observed phenomena are not merely a function of middle ear reflex activity. It is concluded that the lack of inhibition in the operated ear is due to the sectioning of the olivocochlear bundle within the inferior vestibular nerve, removing the efferent control of the receptor cells. Otoacoustic emissions recorded during contralateral acoustic stimulation may thus provide a rapid, non-invasive means of investigating the functional of the efferent auditory system.
The disability resulting from uni-or bilateral loss of vestibular function was assessed by exposing subjects, in darkness, to random rotational displacements on a motorized chair away from a "center" position and requiring them to rotate themselves back to center using a "joystick" control. Normal subjects were accurate within 10 to 15 percent over 180-degree rotations. Alabyrinthine subjects failed to sense their rotation to any useful extent. Subjects with unilateral loss of function as a result of surgery produced hypometric responses to ipsilateral rotation and large amplitude, but inaccurate responses to contralateral rotation. This pattern became more symmetric and normometric with adaptation to loss of function. The procedure promises to be a more useful measure of adaptation than assessing vestibulo-ocular reflexes.
The diagnosis of CSF rhinorrhoea on clinical grounds alone can be difficult. We describe how the use of non-invasive electrophoretic analysis of nasal secretions for tau protein (asialotransferrin) helped in the management of cases where the existence of a CSF leak was in doubt. Patients were thus saved unnecessary invasive investigations or surgery. A modification of the method of analysis, which improves diagnostic accuracy, is described.
Plasmacytomas involving the skull base are rare lesions that may be well advanced by the time of diagnosis. Because of their anatomic site they may produce a variety of signs and symptoms, some of which may be vague, often resulting in delays in presentation and in appropriate investigations. We present such a patient, discuss the diagnosis and management, and give a review of the literature.
A 10-year retrospective review of patients presenting with cerebrospinal fluid (CSF) rhinorrhoea was performed and the success and morbidity resulting from extracranial and craniotomy repair techniques were compared. A classification based upon the aetiology of CSF rhinorrhoea is presented and the radiological techniques used to identify the fistula site are discussed. An emphasis is made upon managing patients on an aetiological basis. This study revealed that extracranial methods of repair had a high success rate with low attendant morbidity. Although craniotomy had comparable success rates this was at the expense of an increase in patient morbidity. Where appropriate, extracranial methods of repair should be the preferred surgical option.