Simon Lloyd

Endoscopic CO2 laser management of laryngocele.

Objective To report on the management of laryngoceles by CO2 laser‐assisted endoscopic excision.

Cranial meningiomas in 411 neurofibromatosis type 2 (NF2) patients with proven gene mutations: clear positional effect of mutations, but absence of female severity effect on age at onset

Background Meningiomas have been reported to occur in approximately 50% of neurofibromatosis type 2 (NF2) patients. The NF2 gene is commonly biallelically inactivated in both schwannomas and meningiomas. The spectrum of NF2 mutations consists mainly of truncating (nonsense and frameshift) mutations. A smaller number of patients have missense mutations, which are associated with a milder disease phenotype. Methods This study analysed the cumulative incidence and gender effects as well as the genotype–phenotype correlation between the position of the NF2 mutation and the occurrence of cranial meningiomas in a cohort of 411 NF2 patients with proven NF2 mutations. Results and conclusion Patients with mutations in exon 14 or 15 were least likely to develop meningiomas. Cumulative risk of cranial meningioma to age 50 years was 70% for exons 1–3, 81% for exons 4–6, 49% for exons 7–9, 56% for exons 10–13, and 28% for exons 14–15. In the cohort of 411 patients, no overall gender bias was found for occurrence of meningioma in NF2 disease. Cumulative incidence of meningioma was close to 80% by 70 years of age for both males and females, but incidence by age 20 years was slightly increased in males (male 25%, female 18%; p=0.023). Conversely, an increased risk of meningiomas in women with mosaic NF2 disease was also found.

Neurofibromatosis type 2

Neurofibromatosis type 2 (NF2) is an autosomal-dominant inherited tumour predisposition syndrome caused by mutations in the NF2 gene on chromosome 22. Affected individuals develop schwannomas characteristically affecting both vestibular nerves leading to hearing loss and eventual deafness. Rehabilitation with brain stem implants and in some cases cochlear implants is improving this outcome. Schwannomas also occur on other cranial nerves, on spinal nerve roots and peripheral nerves. Meningiomas and ependymomas are other tumour features. In excess of 50% of patients represent de novo mutations and as many as 33% are mosaic for the underlying disease causing mutation. Truncating mutations (nonsense, frameshift insertions/deletions) are the most frequent germline events and cause the most severe disease, whilst single and multiple exon deletions are common and are usually associated with milder NF2. A strategy for detection of the latter is vital for a sensitive genetic analysis. NF2 represents a difficult management problem with most patients facing substantial morbidity and reduced life expectancy. Surgery remains the focus of current management although watchful waiting and occasionally radiation treatment have a role. We are seeing the advent of tailored drug therapies aimed at the genetic level and these are likely to provide huge improvements for this devastating, life limiting condition.

Developmental changes in cochlear orientation--implications for cochlear implantation.

Objectives: To investigate changes in cochlear orientation with age and discuss the implications of any change with respect to cochlear implantation. Study Design: Cross-sectional study of computed tomographic scans of the temporal bones in patients with no congenital abnormalities. Patients: One hundred fifty-nine patients were included in the study, making a total of 318 ears. The age range was 9 months to 85 years. Intervention: Axial computed tomographic scans showing the basal turn of the cochlea were identified. The angle of the basal turn of the cochlea was measured by drawing a line through the long axis of the basal turn and measuring its angle with a line drawn through the midsagittal plane. The patients were grouped according to age, and a 1-way analysis of variance was used to identify any statistically significant change in basal turn angulation. Interobserver and intraobserver errors were calculated and presented as repeatability coefficients. The basal turn angles of 3 difficult cases of cochlear implantation were related to the findings. Results: The mean basal turn angle was 54.6 degrees (range, 46.8-63.8 degrees; standard deviation, 3.5). There was a statistically significant reduction in the angulation of the basal turn with increasing age (F = 10.1; p = 0.002). The majority of the change occurs between the ages of 11 and 15 years. The interobserver reliability coefficient was 4.8. The intraobserver reliability coefficient was 2.0. The 3 difficult cases had basal turn angles that were at the upper limit of the reference range. Conclusion: There is a statistically significant reduction in basal turn angulation relative to the midsagittal plane with increasing age. However, care should be taken in interpreting these results in light of the inherent error in the measuring technique, although the intraobserver repeatability coefficient was only 2.0. The more obtuse angulation of the basal turn in children may have implications for cochlear implantation.

Ipsilateral cochlear implantation after cochlear nerve preserving vestibular schwannoma surgery in patients with neurofibromatosis type 2.

Objective To investigate the outcomes from ipsilateral simultaneous or sequential cochlear implantation in patients with neurofibromatosis type 2 (NF2) after vestibular schwannoma removal with cochlear nerve preservation. Study Design Retrospective case series. Setting Single tertiary referral NF2 center. Patients Six patients with NF2. Intervention Removal of vestibular schwannoma (VS) with preservation of the cochlear nerve and cochlear implantation. Four patients had their surgery via a translabyrinthine approach. Two patients had a retrosigmoid approach. A cochlear implant was inserted at the same time as tumor removal in 4 cases and sequentially in 2 cases. Main Outcome Measures Surgical and audiometric outcomes using Bamford-Kowal-Bench (BKB) and City of New York University (CUNY) sentence scores. Results The average age at implantation was 24 years (range, 15–36 yr). Follow-up ranged from 5 to 93 months, with an average of 38 months. All patients had useful hearing in the contralateral ear before surgery. One patient gained no benefit from cochlear implantation and proceeded to have an auditory brainstem implant. Of those that had functional cochlear nerves, the average BKB score in quiet was 64%, BKB score in noise was 42%, and CUNY score with lipreading was 97%. Results varied within the group, but all patients gained significant benefit and continue to use their CI at least intermittantly. Conclusion The present series demonstrates that in selected cases, cochlear implantation can be successful after a translabyrinthine approach for VS removal and for restoring hearing after failed retrosigmoid hearing preservation surgery. All patients found the cochlear implant offered useful hearing even in the presence of contralateral hearing.

English consensus protocol evaluating candidacy for auditory brainstem and cochlear implantation in neurofibromatosis type 2

Objective Hearing loss resulting from bilateral vestibular schwannomas (VSs) has a significant effect on the quality of life of patients with neurofibromatosis Type 2 (NF2). A national consensus protocol was produced in England as a guide for cochlear implantation (CI) and auditory brainstem implantation (ABI) in these patients. Study Design Consensus statement. Setting English NF2 Service. Participants Clinicians from all 4 lead NF2 units in England. Main Outcome Measures A protocol for the assessment, insertion and rehabilitation of CI and ABI in NF2 patients. Results Patients should undergo more detailed hearing assessment once their maximum aided speech discrimination score falls below 50% in the better hearing ear. Bamford-Kowal-Bench sentence testing scores below 50% should trigger assessment for auditory implantation, as recommended by the National Institute for Clinical Excellence guidelines on CI. Where this occurs in patients with bilateral stable VS or a unilateral stable VS where the contralateral cochlear nerve was lost at previous surgery, CI should be considered. Where VS surgery is planned, CI should be considered where cochlear nerve preservation is thought possible, otherwise an ABI should be considered. Intraoperative testing using electrically evoked auditory brainstem responses or cochlear nerve action potentials may be used to determine whether a CI or ABI is inserted. Conclusion The NF2 centers in England agreed on this protocol. Multisite, prospective assessments of standardized protocols for auditory implantation in NF2 provide an essential model for evaluating candidacy and outcomes in this challenging patient population.

Characterizing human vestibular sensory epithelia for experimental studies: new hair bundles on old tissue and implications for therapeutic interventions in ageing

Balance disequilibrium is a significant contributor to falls in the elderly. The most common cause of balance dysfunction is loss of sensory cells from the vestibular sensory epithelia of the inner ear. However, inaccessibility of inner ear tissue in humans severely restricts possibilities for experimental manipulation to develop therapies to ameliorate this loss. We provide a structural and functional analysis of human vestibular sensory epithelia harvested at trans-labyrinthine surgery. We demonstrate the viability of the tissue and labeling with specific markers of hair cell function and of ion homeostasis in the epithelium. Samples obtained from the oldest patients revealed a significant loss of hair cells across the tissue surface, but we found immature hair bundles present in epithelia harvested from patients >60 years of age. These results suggest that the environment of the human vestibular sensory epithelium could be responsive to stimulation of developmental pathways to enhance hair cell regeneration, as has been demonstrated successfully in the vestibular organs of adult mice.

Reactivation and centripetal spread of herpes simplex virus complicating acoustic neuroma resection

BACKGROUND Herpes simplex is a common human pathogen that has rare but severe manifestations including encephalitis. CASE DESCRIPTION A 44-year-old man underwent uneventful resection of an acoustic neuroma. Postoperatively, he developed swinging pyrexia, vomiting, and episodic confusion. Analysis of cerebrospinal fluid showed a lymphocytosis, and polymerase chain reaction revealed herpes simplex DNA. After treatment of herpes encephalitis with acyclovir, the patient made a good recovery. CONCLUSION Herpes encephalitis is a rare complication of neurosurgical procedures, and the most likely etiology is reactivation of latent infection from manipulation of cranial nerves.

Growth characteristics of vestibular schwannomas.

Objective To assess the growth characteristics of small- to medium-sized vestibular schwannomas in patients undergoing watch, wait, and rescan management. Study Design Cohort study using prospectively collected size and tumor morphology data. Setting Tertiary referral center for cranial base surgery. Subjects and Methods Three hundred eighty-one patients with sporadic unilateral vestibular schwannomas and 2 or more magnetic resonance scans were included. Linear measurements were used to assess tumor size. The point of growth and pattern of growth progression were assessed. Factors influencing growth were investigated. Results Approximately 33% of tumors demonstrated significant growth. Mean size at presentation was 9.9 mm (standard deviation [SD]. 4.8). For growing tumors, mean size at final review was 13.7 mm (SD, 4.8). This was a statistically significant increase in size (p < 0.0001). Mean annual change in size for growing tumors was 2.3 mm (SD, 2.3). 52.4% of growing tumors showed radiologically demonstrable first growth within 18 months of presentation. Approximately 7.2% of tumors showed radiologically demonstrable first growth after 5 years of follow-up. There were no demographic or morphologic predictors of growth. Conclusion Tumor growth is usually slow and is most likely to occur within the first 3 years of observation. Growth may occur after five years of follow-up. A protocol for the scanning of patients is suggested based on the findings of the study.

Hearing preservation cochlear implantation in adolescents.

Objective This study describes our experience of cochlear implantation (CI) with hearing preservation in adolescents. Our aim was to determine if hearing preservation is successful in this population, if the preserved hearing is maintained, and what the potential benefit of preserving hearing in this population is. Patients Fourteen profoundly deaf adolescents with preservation of low-frequency hearing (125, 250, and 500 Hz). Intervention Twelve adolescents had a single-sided CI, and two had bilateral CI. All were having their first implantation, and all patients had hearing preservation surgery (soft surgery). Main Outcome Measures Hearing preservation was measured with preoperative and postoperative pure-tone audiograms. Speech audiometry was performed before implantation and at subsequent follow-up appointments. Results Hearing preservation (measurable hearing thresholds) was achieved in 13 of 14 patients. Average follow-up was 2 years 10 months (range, 4 mo–4 yr 9 mo). Three of 13 patients with initial successful hearing preservation had deterioration of their hearing at subsequent follow-up. The addition of naturally preserved hearing to the cochlear implant improved speech audiometry scores compared with using the implants in isolation. Conclusion This study demonstrates that residual hearing can be consistently preserved and maintained in adolescents during the short-/medium-term using a soft surgical technique to insert standard-length electrodes. The potential benefit of preserving residual low-frequency hearing seems to be improvement in speech discrimination in challenging hearing conditions, although larger studies are required.