Faculty Bibliography

INTRODUCTION: Until recently, postimplant meningitis was infrequently reported and felt to be uncommon. However, in the spring of 2002, there was a sudden increase in the number of reported cases of postimplantation meningitis in both Europe and North America. OBJECTIVE: Because complications of surgery often tend to be underreported, we decided to survey all cochlear implant centers in North America to determine the true incidence of postimplant meningitis and to learn more about the demographics and risk factors. STUDY DESIGN: We conducted a prospective study. A survey instrument was designed asking surgeons the number of implants performed and whether they had seen any cases of meningitis after implantation. If the answer was affirmative, they were asked to respond to a 20-point questionnaire. This instrument was sent to all 401 cochlear implant centers in North America. SETTING: Tertiary care referral centers. PATIENTS: We studied all patients having received cochlear implants in North America. MAIN OUTCOME MEASURES: Number of cases of postimplant meningitis, age of patients, device used, cochlear and temporal bone abnormalities, treatment, and outcomes. RESULTS: Meningitis is more common than previously thought. Risk factors included young age, cochlear dysplasia, temporal bone abnormalities, and the use of a two-part electrode system. This survey led to the involvement by the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention in a much more intensive analysis of a subset of the cases. CONCLUSIONS: Postimplant meningitis is related to patient, surgical, and device factors. By being aware of the risk factors involved, adhering to sound surgical principles such as packing of the cochleostomy with soft tissue, appropriately vaccinating patients, and eliminating any potentially traumatic electrode arrays, the incidence of meningitis should be significantly diminished

Facial nerve outcomes and surgical complication rates for other cranial nerves were evaluated retrospectively after the resection of large acoustic neuromas. The charts of all patients who underwent surgical removal of an acoustic neuroma between 1992 and 2001 at New York University Medical Center were reviewed. Fifty-four patients with tumors measuring 3 cm or larger were included in the study. Four patients had neurofibromatosis type 2, two of whom underwent bilateral removal of acoustic neuromas. Translabyrinthine microsurgical removal of tumor was performed in 47 of 56 cases (84%). In all cases, EMG monitoring, improved sharp microdissection, and ultrasonic aspiration were employed. Facial nerve function was assessed using the House-Brackmann facial nerve grading system immediately after surgery and at follow-up visits. A House-Brackmann grade III or better was achieved in 90% of patients, and a grade II or better was achieved in 84% of patients. Ultimate facial nerve outcome was excellent after the surgical resection of large acoustic neuromas. Preoperative cranial nerve palsies also improved after surgery. The translabyrinthine approach for tumor removal is our treatment of choice for acoustic neuromas 3 cm or larger

OBJECTIVES/HYPOTHESIS: Postoperative cerebrospinal fluid (CSF) leak is reported in 2% to 30% of cases following vestibular schwannoma surgery. The authors' current surgical techniques for translabyrinthine, retrosigmoid transmeatal, and middle cranial fossa approaches have evolved from analysis of their prior experience in an effort to minimize their complication rate. The authors evaluated the efficacy of their current surgical technique in decreasing the postoperative CSF leak rate. STUDY DESIGN: Retrospective review. METHODS: The vestibular schwannoma database from the New York University Medical Center (New York, NY) neurotological service was reviewed. Data were extracted for type of approach, tumor size, and CSF leak rate. Liberal leak criteria were used. Surgical techniques and management of CSF leak were reviewed. RESULTS: Data from 215 patients who had surgery from 1995 to 2000 manifested a 6.6% CSF leak rate for primary surgeries. This compared favorably with the authors' 17% overall CSF leak rate in 555 total primary surgeries performed between 1979 and 1995. Translabyrinthine closure was performed with dural sutures used as a sling across the posterior fossa dura and abdominal fat placed as a series of corks through the sutures. Abdominal fat was used to obliterate the mastoid cavity in conjunction with aditus and mastoid obliteration. Attention must be paid to soft tissue obliteration of potentially open air cell tracts. Retrosigmoid transmeatal closure was performed with a soft tissue graft in the internal auditory canal drill-out held in position by a 'saloon-door' dural flap. Bone wax was used to block perimeatal cells in all cases. Watertight dural closure was achieved with a sutured temporalis fascia graft. Abdominal fat obliteration of the mastoidectomy cavity was performed with an additional firm pressure from the 'Palva' periosteal flap. Middle cranial fossa closure was performed with attention to potential air cell tracts of the internal auditory canal drill-out, as well as abdominal fat graft, tissue glue, and bone wax. Fibrin glue was used in all approaches to temporarily secure fat in situ. Management of CSF leaks starts with nonoperative measures including bed rest, oversewing of incisional wounds, and placement of a lumbar subarachnoid spinal fluid diversion drain. If these conservative measures fail, repeat exploration is necessary and is directed at identifying and corking the cell or cells (usually perimeatal or perilabyrinthine) opening directly into the posterior fossa. CONCLUSION: Evolution in surgical techniques, with particular attention to exposed air cell tracts, abdominal fat graft, and Palva periosteal flap for closure, has had a significant effect in decreasing the author's CSF leak rate after vestibular schwannoma surgery. Conservative management was successful in approximately 50% of cases. Repeat exploration, when needed, was directed at blocking the air cell tract (usually perimeatal or perilabyrinthine) responsible for the CSF leak

Despite being the foundation of, or supplement to, many skull base exposures, the retrolabyrinthine approach has not been adequately illustrated in the skull base literature. As an aid to skull base surgeons in training, this article provides a step-by-step description of the microsurgical anatomy and operative nuances of this important technique

OBJECTIVE: To evaluate the efficacy of cochlear implants in human immunodeficiency virus-infected individuals and correlate these results with a proposed pathophysiological mechanism of human immunodeficiency virus-associated hearing loss. STUDY DESIGN: Retrospective case series and temporal bone analysis of deceased human immunodeficiency virus-positive patients. SETTING: Tertiary care hospital. PATIENTS: Seven human immunodeficiency virus-positive individuals with profound sensorineural hearing loss. INTERVENTION: Cochlear implantation at New York University Medical Center. METHODS: The surgical outcomes and complications were analyzed. Additionally, electron microscopic and immunohistochemical findings of cadaver temporal bone specimens of other known human immunodeficiency virus-positive individuals were reviewed. The performance results of the human immunodeficiency virus-positive cochlear implant patients were then correlated with the previously hypothesized pathophysiological mechanism of human immunodeficiency virus-associated hearing loss. RESULTS: The patients had a varied performance with cochlear implantation, and as a group performance was good. There were no surgical complications or postoperative complications. The good performance of these patients supports the hypothesis that the mechanism of human immunodeficiency virus-associated deafness involves infiltration, malfunction, and premature degeneration of the hair cells and supportive cells of the cochlea. CONCLUSIONS: Human immunodeficiency virus-positive individuals benefit from cochlear implantation without increased surgical risk

HYPOTHESIS: Real-time intraoperative fluoroscopy is a useful adjunct to cochlear implantation in selected cases. The advantages include the avoidance of complications such as extracochlear array placement, intrameatal array insertion, and avoidance of significant bending or kinking. This is particularly useful when implanting a severely abnormal cochlea. BACKGROUND: The technique was initially developed for laboratory study of electrode prototypes in cadaver temporal bones to evaluate insertion dynamics and mechanisms of intracochlear trauma. The technique was subsequently adapted for use in live surgeries. METHODS: Live surgeries were performed using fluoroscopic guidance on nine patients. RESULTS: Five patients were implanted with the Nucleus 24 RCS during preclinical trials. Two patients with severe cochlear malformations were implanted with a Nucleus CI24M straight array. Two patients with severe cochlear ossification were implanted with the Nucleus CI24 double array. Appropriate insertions were achieved without electrode damage in all cases. CONCLUSIONS: Intraoperative fluoroscopy is a useful adjunct to cochlear implantation, which can be performed with minimum risk to the patient and operating room staff if the outlined precautions are taken. Intraoperative fluoroscopy is indicated in cases where the intracochlear behavior of the electrode array cannot be predicted, a condition encountered when implanting new electrode designs, cases with severely malformed inner ears, or cases of severe intraluminal obstruction requiring a double-array insertion

OBJECTIVE: Since 1987, when the use of multichannel cochlear implants was initiated in children, candidacy has expanded; many thousands of children have received these devices, and results have revealed a wide range of performance. However, few long-term studies exist on a large population of these children. There have been concerns expressed that cochlear implant function might degrade over time, that devices and electrodes might migrate and extrude in the growing child, or that there might even be a deleterious effect of long-term stimulation of the cochlear nerve. The purpose of this study was to explore the long-term effects of implantation as a function of performance over time, reimplantation, and educational factors. STUDY DESIGN AND SETTING: We studied 81 children who received implants at a major academic medical center and were followed for 5 to 13 years. RESULTS: Results revealed significant gains in speech perception, use of oral language, and ability to function in a mainstream environment. There was no decrease in performance over time and no significant incidence of device or electrode migration or extrusion, and device failure did not cause a deterioration in long-term outcome. CONCLUSIONS: Multichannel cochlear implants in children provide perception, linguistic, and educational advantages, which are not adversely affected by long-term electrical stimulation

OBJECTIVE: To determine the efficacy of cochlear implants with current processing strategies in children and adults with long-term congenital deafness, and to determine whether the growth of auditory perceptual skills in these patients is similar to the data reported for patients who have undergone implantation with earlier devices and coding strategies. STUDY DESIGN: A prospective study of children and adults fulfilling the study inclusion criteria. SETTING: University medical center. PATIENTS: Thirty-five congenitally deaf children who received implants after the age of 8 years and 14 congenitally deaf adults who received implants as adults participated in this study. Length of device use ranged from 6 months to 3 years. MAIN OUTCOME MEASURES: Open set phoneme, word recognition tests, and sentence recognition tests were administered in quiet and noise auditory only conditions preoperatively and postoperatively. Changes in test scores were examined by paired t tests, and differences between groups were compared by Student's t tests. Spearman correlation coefficients were calculated to identify associations between scores and subject characteristics. A two-sided alpha of less than 0.05 was considered statistically significant. RESULTS: The results indicated significant improvement in open set speech perception skills in the children after implantation; the adults demonstrated improved mean scores on both word and sentence recognition. A shorter length of deafness correlated with better postoperative performance, but all subjects continued to improve over time. The improvement in test scores was similar between the devices, and no significant differences were detected between the different processing strategies. CONCLUSION: Children and adults with long-term congenital deafness can obtain considerable open set speech understanding after implantation. Length of deafness (age at implantation), length of device use, and mode of communication contribute to outcome