Hearing Response Following Internal Auditory Canal Decompression in Neurofibromatosis Type 2.

BACKGROUND: Hearing response following an osteodural decompression of the internal auditory canal (IAC) is controversial. OBJECTIVE: To evaluate the course of auditory brainstem responses (ABRs) and the early hearing response during the first year following IAC decompression for small to medium-sized vestibular schwannomas occurring in neurofibromatosis type 2 (NF2). METHODS: Retrospective chart review of middle fossa craniotomy for IAC osteodural decompression in NF2-related vestibular schwannomas. RESULTS: Twelve NF2 patients were operated on from 2011 to 2016 for IAC decompression. All had NF2 according to the Manchester criteria. All had a progressive change of their ABRs documented from the diagnosis of NF2 over a mean period of 6.25 [0.36;10.9] yr. Treatment was proposed to stop hearing progression based on the speech discrimination scores (SDSs; n = 4) or for hearing maintenance (n = 8). In patients with prior hearing progression, hearing responses were observed in 3 of the 4 patients during the first year. One patient kept on progressing. In the hearing maintenance group, the SDSs remained stable. SDSs improved from 85% [20-100] to 92.5% [60-100] on average (n = 12) and from 55% [20-80] to 77.5% [50-100] in the hearing progression group (n = 4). ABRs improved in 4 patients following decompression. CONCLUSION: IAC decompression allows early objective hearing responses in select patients. We suggest that the procedure should be offered to patients with hearing progression based on their SDSs and/or associated progressive increases in their wave III and V latencies on ABRs.

Pediatric neurofibromatosis type 2: clinical and molecular presentation, management of vestibular schwannomas, and hearing rehabilitation.

OBJECTIVE: This study aims to describe the clinical and molecular presentation of pediatric neurofibromatosis type 2 (NF2) and the subsequent management of vestibular schwannomas (VS) and hearing rehabilitation. METHODS: This is a single-center retrospective study of neurofibromatosis type 2 diagnosed before the age of 18 years old from 1997. Natural history of vestibular schwannomas and surgical outcomes were evaluated using volumetric MRI, hearing, and facial nerve assessment. Patients included in chemotherapy protocols were excluded. RESULTS: From a database of 80 patients followed up for NF2 on a regular basis, 25 patients were eligible (11 sporadic cases, 14 inherited in five families). The mean age at diagnosis was 11.6 years old. The average clinical follow-up was 6.5 years. NF2 mutation was identified in 81 % of the probands. The average growth rate based on the maximum linear diameter (DGR) was 1.68 mm/year (n = 33, average follow-up 4.22 years) and 545 mm3/year in volumetric assessment (VGR) for VS larger than 1 cm (n = 21, average follow-up 3.4 years). In unoperated ears, hearing was stable in about 50 % of ears. The mean change in dB HL was 9.5 dB/year for pure-tone average and 3.5 for speech-recognition threshold (n = 34, 5.5 years 1-12). Eight children required removal through a translabyrinthine approach (mean follow-up was 4.5 years), six patients were operated on for hearing preservation (mean postoperative follow-up 4.3 years). Six patients were eligible for hearing rehabilitation with cochlear implantation (I), and five received placement of an auditory brainstem implant. CONCLUSION: Early diagnosis and treatment of small growing VS should be carefully discussed considering familial history and possible rehabilitation with a CI.

Long-term growth rate of vestibular schwannoma in neurofibromatosis 2: A volumetric consideration.

OBJECTIVES/HYPOTHESIS: To determine the long-term growth rate of vestibular schwannoma (VS) in neurofibromatosis type 2 (NF2) patients based on volumetric measurements. STUDY DESIGN: Retrospective review. METHODS: We retrospectively reviewed magnetic resonance imaging (MRI) scans acquired from patients with NF2 from 1999 to 2013. Patients with an annual radiologic follow-up over at least 3 consecutive years were included. Volumetric VS growth was prospectively measured using a three-dimensional imaging workstation and through manual contouring of the lesion. Time to tumor progression was assessed according to the Response Evaluation in Neurofibromatosis and Schwannomatosis Tumor Measurement Group. RESULTS: Eighteen patients presenting with a total of 26 VSs were included. The mean age at diagnosis was 26.1 years (range, 7 to 49 years). One hundred five MRI scans were analyzed during a median radiological follow-up of 5.6 years (range, 3 to 12 years). The annual volume and diameter growth rates were respectively 218.3 mm(3) /yr (range, -10 to 1,250 mm(3) /yr) and 0.9 mm/yr (range, -0.5 to 4.5 mm/yr). Time to tumor progression was 3 years (median survival). There was a weak correlation between volumetric and linear measurements (P < .0001, linear regression, n = 26, r(2) = 0.58). Among the 26 VSs, 76.9% (20/26) showed progression (VS growth more than 20%), 19.2% were stable, and 3.9% (1/26) exhibited shrinkage (spontaneous regression of more than 20% of the initial volume). CONCLUSIONS: This study helps to assess the long-term growth profile of VS in a population of NF2 patients with untreated VS. These data could help to better acknowledge VS natural growth history. LEVEL OF EVIDENCE: 4 Laryngoscope, 126:2358-2362, 2016.

The value of a rapid contrast-enhanced angio-MRI protocol in the detection of head and neck paragangliomas in SDHx mutations carriers: a retrospective study on behalf of the PGL.EVA investigators.

OBJECTIVES: To assess the performance of a simplified MRI protocol consisting of a contrast-enhanced three-dimensional MR angiography (CE-MRA) in association with a post-contrast T1-weighted sequence (T1WIV) for the detection of HNPGLs in SDHx mutation carriers. METHODS: This retrospective sub-study is based on the multicenter PGL.EVA cohort, which prospectively enrolled SDHx mutation carriers from 2005 to 2009; 157 index cases or relatives were included. CE-MRA and the T1WIV images were read solely with knowledge of the clinical data but blind to the diagnosis. Sensitivity, specificity and likelihood ratios for the simplified MRI protocol were compared to the full MRI protocol reading results and to the gold standard status obtained through the consensus of an expert committee. RESULTS: The sensitivity and specificity of the readings of the simplified MRI protocol were, respectively, 88.7 % (95 % CI = 78.1-95.3) and 93.7 % (95 % CI = 86.8-97.7) versus 80.7 % (95 % CI = 68.6-89.6) and 94.7 % (95 % CI = 88.1-98.3) for the readings of the full MRI protocol. CONCLUSIONS: The simplified post-contrast MRI with shorter duration (5 to 10 minutes) showed no performance difference compared to the lengthy standard full MRI and can be proposed for the detection of head and neck paragangliomas (HNPGLs) in SDHx mutation carriers. KEY POINTS: • Rapid angio-MRI protocol and the usual lengthy protocol show equal diagnostic performance. • The CE-MRA is the key sequence for the detection of HNPGLs. • The T1WIV sequence assists in localizing HNPGLs.

Bevacizumab decreases vestibular schwannomas growth rate in children and teenagers with neurofibromatosis type 2.

Vestibular schwannoma (VS) growth in neurofibromatosis type 2 (NF2) can be responsible for brainstem compression and hearing loss. Surgical removal remains the standard therapy despite potential morbidity. Previous studies suggested that the inhibition of the VEGF-pathway with bevacizumab could result in hearing improvement, reduction of the tumor volume or both in adults. We retrospectively describe the French experience of bevacizumab treatment delivered for progressive VS in pediatric NF2 patients. Patients received Bevacizumab 5 or 10 mg/kg every 2 weeks according to the physician's choice. Follow-up included clinical assessment, audiometry and volumetric MRI every 3-6 months. Seven patients harboring 11 VS were included. The median age at inclusion was 15 years (11.4-18.8), and the median treatment duration was 11.3 months (3.2-55.6). At baseline, the median tumor volume was 1.2 cm(3) (0.52-13.5) and the median word recognition score was 90 % (0-100). We observed one major response, two minor responses and a decrease in the rate of tumor growth for the 4 other patients. The median annual growth rate before treatment was significantly higher than after 1 year of treatment (138 vs. 36 %, n = 5, p = 0.043). We noted one hearing improvement over the course of 1 year under treatment (hearing response rate was 14 %). Overall, the treatment was well tolerated. Our study supports that bevacizumab is an attractive therapeutic option for pediatric NF2 patients with growing VS. Thorough multidisciplinary evaluation is necessary to identify the best candidates prior to treatment. It is likely that a better functional outcome would be expected if targeted therapies were discussed early in the management of the disease.

Middle fossa approach for resection of vestibular schwannoma: impact of cochlear fossa extension and auditory monitoring on hearing preservation.

OBJECTIVE: To analyze the impact of patient selection and auditory monitoring on hearing results after middle fossa craniotomy approach for resection of a vestibular schwannoma (VS). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Patients undergoing a middle fossa craniotomy for resection of VS at a single institution between 1995 and 2006 were included in the study population. Patients presenting with Neurofibromatosis Type 2 or who underwent a combined approach (middle fossa and retrosigmoid) were excluded. MAIN OUTCOME MEASURES: Hearing preservation as measured by serial audiograms. RESULTS: Seventy-seven patients were identified. Before excluding patients with cochlear fossa enhancement and the use of auditory monitoring, 47% of the patients maintained serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery Class A or B). By selecting tumors that did not involve the cochlear fossa and using auditory monitoring, serviceable postoperative hearing was preserved in 76% of the patients. CONCLUSION: Modification of our selection criteria for surgery and the use of auditory monitoring have improved our hearing results for patients undergoing a middle fossa approach for resection of VS from 47% to 76%.

Diffusion-weighted MR imaging sequence in the detection of postoperative recurrent cholesteatoma.

PURPOSE: To prospectively evaluate a fast spin-echo (SE) diffusion-weighted sequence for magnetic resonance (MR) imaging of recurrent cholesteatoma in patients who have undergone middle ear surgery. MATERIALS AND METHODS: The study was approved by the institutional review board, and informed consent was obtained from all patients. Twenty-four patients (10 female and 14 male patients; mean age, 44 years) who had undergone resection of cholesteatoma were referred for MR imaging. MR imaging was performed with a 1.5-T unit by using unenhanced diffusion-weighted fast SE imaging at b factors of 0 and 800 sec/mm(2), unenhanced T2-weighted fast SE imaging, unenhanced T1-weighted SE imaging, and delayed contrast material-enhanced T1-weighted imaging. Two radiologists evaluated the diffusion-weighted fast SE images for the presence of a high-signal-intensity cholesteatoma. Results from MR imaging were compared with reports from second- or third-look surgery. Interobserver agreement was assessed with the kappa statistic. RESULTS: A recurrent cholesteatoma was correctly identified in 13 of 14 patients with diffusion-weighted fast SE images obtained with a b factor of 800 sec/mm(2), for a positive predictive value of 93%. In patients without recurrent cholesteatoma, all diffusion-weighted fast SE MR images obtained with a b factor of 800 sec/mm(2) were correctly interpreted as showing no high signal intensity. Thus, the negative predictive value was 100%. Sensitivity and specificity were 100% (13 of 13 patients) and 91% (10 of 11 patients), respectively. Interobserver agreement was excellent (kappa = 0.92). The smallest recurrent cholesteatoma was 5 mm in diameter, and this was correctly detected with the diffusion-weighted fast SE sequence. CONCLUSION: Diffusion-weighted fast SE imaging enables the depiction of recurrent cholesteatoma in patients who have undergone middle ear surgery.

Mass screening for retrocochlear disorders: low-field-strength (0.2-T) versus high-field-strength (1.5-T) MR imaging.

BACKGROUND AND PURPOSE: In patients with clinical symptoms suggestive of a retrocochlear disorder, contrast-enhanced T1-weighted spin-echo (SE) high-field-strength MR imaging is considered the criterion standard in assessing vestibular schwannoma. However, only 10-20% of its findings are pathologic. Our purpose was to prospectively compare the performance of low-field-strength MR imaging in screening for retrocochlear disorders, with high-field-strength MR imaging as the criterion standard. METHODS: A total of 287 patients with suspected retrocochlear disease underwent axial 1.5-T MR imaging with a T1-weighted SE sequence before and after contrast enhancement and with a high-resolution T2-weighted construction interference in steady state sequence. At immediate follow-up, the same patients underwent axial 0.2-T T1-weighted SE imaging without additional contrast enhancement. Results were classified as negative, positive, or uncertain and were analyzed in light of the patients' clinical symptoms. RESULTS: MR imaging at 1.5 T depicted 63 disorders (21.95%), including 53 schwannomas, three other tumors, and seven other disorders (ie, gadolinium-enhancing inner ear, facial nerve, or meninges). MR imaging at 0.2 T showed evidence of 58 disorders; five disorders were not detected, although all schwannomas and other tumors were seen, including those smaller than 2 mm, and only two (28.6%) of the other disorders were detected. When correlated with clinical data, results showed that the five undetected disorders occurred in patients with unusual clinical signs. CONCLUSION: MR imaging at 0.2 T provided high sensitivity in detecting vestibular schwannoma of the internal auditory canal or cerebellopontine angle; it can be used for mass screening for this disease. Positive and uncertain imaging findings should be followed up with high-field-strength MR imaging.