Facial Nerve Outcome and Tumor Control Rate as a Function of Degree of Resection in Treatment of Large Acoustic Neuromas: Preliminary Report of the Acoustic Neuroma Subtotal Resection Study (ANSRS).

BACKGROUND: Patients with large vestibular schwannomas are at high risk of poor facial nerve (cranial nerve VII [CNVII]) function after surgery. Subtotal resection potentially offers better outcome, but may lead to higher tumor regrowth. OBJECTIVE: To assess long-term CNVII function and tumor regrowth in patients with large vestibular schwannomas. METHODS: Prospective multicenter nonrandomized cohort study of patients with vestibular schwannoma ≥2.5 cm who received gross total resection, near total resection, or subtotal resection. Patients received radiation if tumor remnant showed signs of regrowth. RESULTS: Seventy-three patients had adequate follow-up with mean tumor diameter of 3.33 cm. Twelve received gross total resection, 22 near total resection, and 39 subtotal resection. Fourteen (21%) remnant tumors continued to grow, of which 11 received radiation, 1 had repeat surgery, and 2 no treatment. Four of the postradiation remnants (36%) required surgical salvage. Tumor regrowth was related to non-cystic nature, larger residual tumor, and subtotal resection. Regrowth was 3 times as likely with subtotal resection compared to gross total resection and near total resection. Good CNVII function was achieved in 67% immediately and 81% at 1-year. Better immediate nerve function was associated with smaller preoperative tumor size and percentage of tumor left behind on magnetic resonance image. Degree of resection defined by surgeon and preoperative tumor size showed weak trend toward better late CNVII function. CONCLUSION: Likelihood of tumor regrowth was 3 times higher in subtotal resection compared to gross total resection and near total resection groups. Rate of radiation control of growing remnants was suboptimal. Better immediate but not late CNVII outcome was associated with smaller tumors and larger tumor remnants. ABBREVIATIONS: CNVII, cranial nerve VIIGTR, gross total resectionHB, House-BrackmannMRI, magnetic resonance imageNTR, near total resectionSTR, subtotal resection.

The Impact of Postmeningitic Labyrinthitis Ossificans on Speech Performance After Pediatric Cochlear Implantation.

OBJECTIVE: 1) To characterize pediatric cochlear implant performance in patients with hearing loss secondary to bacterial meningitis. 2) To evaluate performance differences in patients with and without labyrinthitis ossificans (LO). STUDY DESIGN: Retrospective case review. SETTING: A large university-based multidisciplinary cochlear implant program. PATIENTS: Forty-nine patients with hearing loss from bacterial meningitis who received cochlear implants from 1991 to 2011. Thirty-nine patients had adequate data for analysis. INTERVENTION: Cochlear implantation with postoperative performance evaluation. MAIN OUTCOME MEASURE(S): Speech perception category (SPC). RESULTS: Nineteen (48.7%) patients had intraoperative evidence of LO. Fourteen patients (70.0%) without LO compared with seven (36.8%) with LO developed open-set speech after implantation. There was a trend toward better postimplant SPC outcomes in patients without LO that did not reach statistical significance (p = 0.17). The presence of LO negatively correlated with classroom placement (p < 0.05). Analysis of each group individually demonstrated statistically significant improvement in pre- versus postimplant SPC outcomes (p < 0.001). CONCLUSION: The presence of LO may negatively affect performance in pediatric patients receiving a cochlear implant for hearing loss secondary to bacterial meningitis.

A retrospective analysis of tumor volumetric responses to five-fraction stereotactic radiotherapy for paragangliomas of the head and neck (glomus tumors).

BACKGROUND: Skull base paragangliomas (SBP) are locally expansile tumors that can be treated with stereotactic radiotherapy with favorable results. This report describes the results of 31 patients with SBP treated with CyberKnife radiotherapy delivering a total dose of 25 Gray in five fractions. METHODS: All patients treated with five-fraction CyberKnife radiotherapy at a single institution were identified between 2007 and 2013. Tumor volumetric analyses were performed to assess responses to radiotherapy. RESULTS: Median follow-up was 24 months with a range of 4-78 months. Local control and overall survival were 100%. Of the 20 patients who presented with tinnitus, 12 reported improvement (60%), of whom 6 reported complete resolution. There was a 37.3% reduction in tumor volume among all patients (p = 0.16). On subset analysis of patients with ≥24 months of follow-up, tumor volume decreased 49% (p = 0.01). The rate of grade 1-2 toxicity was 19%, with no grade 3 or worse toxicity. CONCLUSION: A five-fraction CyberKnife-based stereotactic radiotherapy approach is safe and efficacious for the management for patients with SBP. Our findings suggest the potential use of this strategy as a definitive or salvage treatment option for SBP.

High-resolution 3-D T2-weighted imaging in the diagnosis of labyrinthitis ossificans: emphasis on subtle cochlear involvement.

BACKGROUND: Meningitis is the most common cause of acquired sensorineural hearing loss (SNHL) in children. Labyrinthitis ossificans develops in a significant number of patients with meningitis-related SNHL. Reduced T2 signal on MRI within the membranous labyrinth is often noted in the fibrous and ossifying stages of labyrinthitis ossificans. OBJECTIVE: The purpose of this study is to demonstrate the distribution and extent of involvement of the cochlea in children being evaluated for labyrinthitis ossificans; using high-resolution 3-D T2-weighted imaging, and to evaluate for subtle involvement of the scala tympani within the basal turn of the cochlea. MATERIALS AND METHODS: A retrospective review from 2002 to 2012 was performed using a cochlear implant database and PACS search function. Twenty-four patients were found to have MR findings consistent with labyrinthitis ossificans, 13 previously reported. Axial 3-D T2-weighted sequences were obtained in all patients. The presence of abnormal decreased T2 signal within the scala tympani and vestibuli of the cochlea was noted and graded according to the extent. The electronic medical record was reviewed for audiometry and risk factors as well as correlative operative findings. RESULTS: The average age at imaging was 4.2 years. M:F ratio = 5:1. Eighty-eight percent (21/24) of patients had bilateral SNHL. The most common risk factor for labyrinthitis ossificans was meningitis (19/24 or 79%). Eighteen (75%) patients had a history of bacterial meningitis. The mean age for the onset of labyrinthitis was 1.2 years with an average of 2.2-year interval to imaging. Nineteen patients (79%) underwent placement of a cochlear implant. Cochlear obstruction was documented in 83% (40/48) of the ears. Lower grade (1) cochlear obstruction was present in 14 ears and limited to the scala tympani. Statistical analysis was performed correlating MRI imaging and surgical findings. CONCLUSION: Subtle, isolated involvement of the scala tympani within the proximal basal turn is a common finding in labyrinthitis ossificans and history typical for meningitis is not uniformly present. The extent of cochlear obstruction is important and has surgical implications.

Labyrinthitis ossificans: how accurate is MRI in predicting cochlear obstruction?

OBJECTIVE: To determine the accuracy of preoperative MRI in predicting cochlear obstruction in pediatric patients with a history of bacterial meningitis. METHODS: A case series with chart review was performed at a tertiary care multidisciplinary cochlear implant program. Forty-five children with hearing loss that resulted from bacterial meningitis were implanted from 1991 to 2006. Twenty-five children had preoperative MRI with high-resolution axial T2-weighted images to assess for cochlear patency. RESULTS: Seventeen of 25 patients (68%) had surgical evidence of cochlear obstruction. Six patients (37.5%) required circummodiolar drill-outs, and one patient (6.25%) underwent placement of a double array cochlear implant. The nine remaining patients (56%) with cochlear obstruction required removal of fibrous tissue or drilling of the inferior basal turn, but did not require manipulation of the ascending basal turn to achieve full electrode insertion. The sensitivity, specificity, and positive and negative predictive value of MRI predicting intraoperative cochlear obstruction with 95 percent confidence intervals was 94.1 percent (71-99), 87.5 percent (47-99), 94.1 percent (71-99) and 87.5 percent (47-99), respectively. CONCLUSION: Preoperative high-resolution T2 MRI may be useful in predicting cochlear obstruction in patients with a prior history of bacterial meningitis.