Faculty Bibliography

OBJECTIVES: To present a rare case of facial nerve paraganglioma and novel use of a processed allograft for facial nerve reconstruction. STUDY DESIGN: Case report and review of the literature. METHODS: A 34 year old female presented with progressive onset right sided facial palsy for 5 months. CT and MRI demonstrated an irregular mass in the right facial nerve canal from the intratympanic segment to the stylomastoid foramen. RESULTS: Following transmastoid resection, the defect was repaired using processed allograft. Pathologic analysis was consistent with a paraganglioma. Facial nerve paraganglioma is a rare entity that has been reported only 10 times in the literature. CONCLUSIONS: Traditional methods of facial nerve reconstruction, including autologous and cadaveric grafting, can lead to significant patient morbidity. Autologous nerve grafts are the 'gold standard' for superior regenerative capability, but are limited by the length and potential neuroma formation at the donor site. Allogenic grafts from donors or cadavers have shown some efficacy, but can require immunosuppression. The Avance nerve graft is a cadaveric graft, processed and decellularized to maintain an extracellular matrix with laminin and intact endoneural tubes, thus providing support for the growing axon without generating an immune response. Initial studies of the Avance graft in animals and humans have examined repair of peripheral nerves, but this is the first reported case of human facial nerve reconstruction

OBJECTIVES/HYPOTHESIS: Widespread universal newborn hearing screening has led to increased identification of infant hearing loss. Supported by improved diagnostic tools allowing more definitive diagnosis of profound sensorineural hearing loss in young children, cochlear implantation in children <12 months of age is now common. Literature supports short-term safety and improved auditory outcomes in these young children, however long-term data is lacking. The study examines issues of long-term safety and efficacy in cochlear implant patients implanted <1 year of age. STUDY DESIGN: Retrospective chart review. METHODS: Fifty children who received cochlear implants before 1 year of age were followed for up to 7 years. Age at implantation ranged from 5 to 11 months with a mean of 9.1 months. Three patients had simultaneous bilateral implantation at 8 to 9 months of age. Medical records were reviewed for complications incurred during length of device usage, including time of complication, management, and resolution. Auditory assessment included both the Infant-Toddler Meaningful Auditory Integration Scale and tests of speech perception. RESULTS: All 50 patients had full insertions of the electrode array. There were a total of eight complications (16%) in seven patients, three major (6%) and five minor (10%), which occurred at or before 10 months postoperatively. There were no perioperative anesthetic complications. CONCLUSIONS: Cochlear implantation in children <12 months of age is safe and efficacious over an extended period of time. Rates and nature of both major and minor complications are comparable to studies in adults and older children and support continued monitoring of these patients over the long-term

PURPOSE OF REVIEW: Cochlear implantation is a well tolerated and effective procedure in the rehabilitation of profoundly and severely hearing-impaired individuals. Cochlear reimplantation may be necessary for a variety of reasons. The recent literature regarding the indications, surgical considerations, and outcomes in revision cochlear implant (RCI) surgery is reviewed here. RECENT FINDINGS: A small but significant percentage (3-8%) of all cochlear implant procedures requires RCI surgery. The most common indication for RCI is hard failure (40-80%), but other common indications include soft failures, wound complications, infection, improper initial placement, and electrode extrusions. There is a high rate of surgical success in RCI with preservation or improvement of preoperative performance in the majority of patients, in addition to the alleviation of prereimplantation symptoms. Both children and adults benefit from RCI when indicated and experience similar auditory successes following RCI. SUMMARY: The need for RCI is uncommon, but the potential for restoration or improvement in speech perception and alleviation of symptoms exists. Regardless of indication, RCI surgery is well tolerated, and, with thoughtful preparation, individualized patient counseling, and proper surgical technique, most patients can expect successful outcomes

OBJECTIVE: Bilateral sequential cochlear implantation outcomes are dependent on many different factors. Newer technology in the second implanted ear may also contribute to outcome. This study examines the effect of cochlear implant technology on speech recognition outcomes in a population of adult patients who have undergone bilateral sequential implantation using different technologies in each ear. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Twenty adults who underwent bilateral sequential cochlear implantation with different technologies and processing strategies in each ear were patients for this study. Control Group A included patients (n = 8) who were simultaneously implanted, and Control Group B (n = 3) were patients who were sequentially implanted with the same technology. INTERVENTION: Bilateral sequential cochlear implantation. OUTCOME MEASURES: The outcome measure was the Consonant-Nucleus-Consonant monosyllabic word test administered in each implanted ear and in the binaural condition before and 1 year after operation. A multivariate analysis was performed to account for factors including duration of deafness, length of device usage, and severity of deafness. RESULTS: There was significant improvement from before to 1 year after the operation in word scores for the individual ears and in the binaural condition for all groups. All patients were consistent users of both devices, and the use of different technology in the second implanted ear did not affect the patients' ability to benefit from bilateral implantation despite the use of different devices and processing strategies. CONCLUSION: Bilateral sequential implantation with newer and/or differing technology in the second implanted ear did not reduce the benefits of bilateral stimulation and should not be considered a deterrent to second-sided implantation

This paper presents an optimal path planning method of steerable electrode arrays for robot assisted cochlear implant surgery In this paper, the authors present a novel design of steerable electrode arrays that can actively bend at the up An embedded strand in the electrode array provides an active steering degrees of freedom (DoF) This paper addresses the calibration of the steerable electrode arrays and the optimal path planning for inserting it into planar and three dimensional scala tympani models The goal of the path planning is to minimize the intracochlear forces that the electrode array applies on the walls of the scala tympam during insertion This problem is solved by designing insertion path planning algorithms that provide best fit between the shape of the electrode aunty and the curved scala tympani during insertion Optimality measures that account fittape discrepancies between the steerable electrode array and the scala tympam are used to solve for the optimal path planning of the robot Different arrangements of DoF and insertion speed force feedback (ISFF) are simulated and experimentally validated in this paper A quality of insertion metric describing the gap between the steerable electrode array and the scala tympam model is presented and as correspondence to the insertion force is shown The results of using 1DoF 2DoF and 4DoF electrode array insertion setups are compared The 1DoE insertion setup fiver nonsteerable electrode arrays The 2DoF insertion setup uses single axis insertion with steerable electrode arrays. The 4DoF insertion setup allows full control of the insertion depth and the approach angle of the electrode with respect to the cochlea while using steerable electrode arrays It is shown that living steerable electrode arrays significantly reducer the maximal insertion force (59.6% or more) and effectively prevents buckling of the electrode array The 4DoF Insertion setup further reduces the maximal electrode insertion forces The results of using ISFF for steerable electrodes show a slight decrease in the insertion forcer in contrast to a slight increase for nonsteerable electrodes These results show that further research is required in order to determine the optimal ISFF control law and its effectiveness in reducing electrode invention fortes [DOI 10.1115/1.3039513]

OBJECTIVE: To examine speech perception outcomes as related to a reduction in the number of functional electrodes postimplantation and to determine the effect of electrode reduction on subsequent device failure. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic referral center. PATIENTS: Of 1,520 children and adults with full insertions of the Advanced Bionics, Med El, and Nucleus devices, 15 (1%) were patients. Patients were included in the study if all electrodes were functional at initial stimulation, but the number of electrodes in use was subsequently reduced at follow-up programming sessions. Exclusion criteria included partial and split-array electrode insertions. INTERVENTION(S): Patients with bilateral severe to profound sensorineural hearing loss underwent either unilateral or bilateral cochlear implantation. MAIN OUTCOME MEASURE(S): Postimplantation speech perception tests obtained with a full complement of functional electrodes were performed and the results compared to those obtained with 1 or more electrodes removed from the user program. Electrode deactivation was also correlated with device failure. RESULTS AND CONCLUSION: The results of this study indicate that deactivation of cochlear implant electrodes is relatively uncommon, and although the deactivation does not have a direct influence on speech performance outcomes, the loss of 5 or more electrodes can suggest impending device failure. Additionally, those patients with electrode deactivation coupled with a decline in speech perception scores should also be considered at risk for device failure

OBJECTIVES: The purpose of this study is to determine if the performance of the first implanted member of a family predicts the performance of subsequently implanted family members. STUDY DESIGN: Retrospective chart review. METHODS: Seventy-one cochlear implant recipients, each belonging to a family with two or more implanted members, were the subjects of this study. Routine audiometric measurements and age-appropriate speech perception tests were performed pre- and postoperatively. In addition, length of deafness, age at implantation, etiology, and length of device usage were correlated to outcome. RESULTS: All implant recipients within a family showed improvement postimplantation, and the predictive component between family members was strong. Presence of GJB2 mutations and greater age at implantation were predictive of poorer rehabilitative outcome, while length of device usage was associated with improved speech perception scores. CONCLUSIONS: On average, if the first implanted family member performs well with a cochlear implant, those following will do well; however, GJB2-related deafness and increased age at implantation are associated with poorer outcome. These findings have important implications for members of families considering cochlear implantation

OBJECTIVE: To review our experience with partial standard and double-array cochlear implantation in the ossified cochlea. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Twenty cochleae in 19 adult and pediatric patients with ossified cochleae. INTERVENTION(S): Patients underwent either partial insertion of a standard electrode array or double-array electrode insertion for their cochlear implantation. MAIN OUTCOME MEASURE(S): Number of electrodes inserted, number of active electrodes at follow-up, and open-set speech performance. RESULTS: Twelve patients (four children and eight adults) had partial insertion of standard array electrode. The mean number of electrodes inserted and active at follow-up was 14.8 and 11.3, respectively. Eight patients (four children and four adults) had a double-array electrode implanted. The mean number of electrodes inserted and active at follow-up was 18.1 and 16.3, respectively. Open-set speech recognition was better in children regardless of duration of deafness. There were no complications. CONCLUSION: These findings suggest that the double array allows for more usable electrodes than in partially inserted cochlear implant. Compared with adults, children with ossified cochlea do well both in partial standard and double-array insertion. Both insertion techniques are safe, with no complications occurring in our patients. Straight and double arrays should be available in the operating suite for any patient in whom suspected cochlear ossification is confronted

OBJECTIVES: To date, numerous studies have compared functional outcomes between stereotactic radiosurgery (SRS) and microsurgery (MS) in the treatment of vestibular schwannomas (VS). However, most of them involve tumors of difference sizes, radiation dosages, and surgical approaches. Few have systematically compared issues of dysequilibrium. By studying only patients with small tumors and no hearing, we sought to minimize confounding variables. STUDY DESIGN: A retrospective chart review and telephone questionnaire. METHODS: From 1998-2006, 31 patients with small (<1.5 cm) VS and nonserviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery [AAO-HNS] Class C or D) were treated at our institution. Twenty-two were available for follow-up and telephone questionnaire, including the University of California Los Angeles Dizziness Questionnaire (UCLA-DQ). Twelve underwent SRS and 10 underwent MS. All MS patients underwent the translabyrinthine approach to their tumors. Outcomes measurements included tumor control, facial nerve function, tinnitus, trigeminal function, and imbalance. RESULTS: Patients undergoing SRS had comparable rates of tumor control, facial nerve function, tinnitus, and trigeminal function to MS patients. However, SRS did result in statistically significantly worse long-term imbalance when compared with MS patients. Detailed comparisons of the two modalities are made. CONCLUSIONS: In our study population, patients with small tumors and no serviceable hearing, these data suggest that MS results in comparable minimal morbidity with SRS, though posttreatment dysequilibrium is significantly decreased. While the authors recommend translabyrinthine resection of small VS with no hearing in patients able to tolerate surgery, the need for further prospective investigation is clear