Histopathological analysis of a 15-year user of an auditory brainstem implant.

Auditory brainstem implants (ABIs) can provide highly beneficial hearing sensations to individuals deafened by bilateral vestibular schwannomas (neurofibromatosis type 2). Relatively little is known about the status of stimulated neurons after long-term ABI use. Direct examination of the cochlear nuclear complex (CN) of one 5-year ABI user indicated no deleterious effect.

Evolution of techniques for the resection of vestibular schwannomas: from saving life to saving function.

The current state of surgery for vestibular schwannomas (VSs) is the result of a century of step-by-step technical progress by groundbreaking surgeons who transformed the procedure from its hazardous infancy and high mortality rate to its current state of safety and low morbidity rate. Harvey Cushing advocated bilateral suboccipital decompression and developed the method of intracapsular tumor enucleation. Walter Dandy supported the unilateral suboccipital approach and developed the technique of gross-total tumor resection.

Audiologic outcomes with the penetrating electrode auditory brainstem implant.

Objective: The penetrating electrode auditory brainstem implant (PABI) is an extension of auditory brainstem implant (ABI) technology originally developed for individuals deafened by neurofibromatosis type 2. Whereas the conventional ABI uses surface electrodes on the cochlear nuclei, the PABI uses 8 or 10 penetrating microelectrodes in conjunction with a separate array of 10 or 12 surface electrodes. The goals of the PABI were to use microstimulation to reduce threshold current levels, increase the range of pitch percepts, and improve electrode selectivity and speech recognition.

Auditory brainstem implants.

The development of cochlear implantation has allowed the majority of patients deafened after the development of language to regain significant auditory benefit. In a subset of patients, however, loss of hearing results from destruction of the cochlear nerves, rendering cochlear implantation ineffective. The most common cause of bilateral destruction of the cochlear nerves is neurofibromatosis type 2 (NF2).

Surgical salvage after failed irradiation for vestibular schwannoma.

Objectives/hypothesis: Compare vestibular schwannoma (VS) surgical outcome between patients with prior irradiation and those not previously treated.

Study Design: Retrospective review with matched control group.

Methods: Review of tumor adherence to the facial nerve, facial nerve grade, and complications in 38 patients with radiotherapy as a primary procedure before VS surgical removal and a matched random sample of 38 patients with primary surgery.

The evolution of surgical approaches for posterior fossa meningiomas.

Objective: To evaluate surgical outcomes for the treatment of posterior fossa meningiomas at the House Ear Clinic from 1987 to 2001. We review our current treatment algorithm and present our postoperative outcomes with attention to facial and auditory neural preservation.

Study Design: Retrospective review.

The multichannel auditory brainstem implant: how many electrodes make sense?

Object: Development of multichannel auditory brainstem implant (ABI) systems has been based in part on the assumption that audiological outcome can be optimized by increasing the number of available electrodes. In this paper the authors critically analyze this assumption on the basis of a retrospective clinical study performed using the Nucleus 22 ABI surface electrode array.

Methods: The perceptual performances of 61 patients with neurofibromatosis Type 2 were tested approximately 6 weeks after an eight-electrode ABI had been implanted.

Multichannel auditory brainstem implant: update on performance in 61 patients.

Object: Neurofibromatosis Type 2 (NF2) has typically resulted in deafness after surgical removal of bilateral vestibular schwannomas (VSs). Cochlear implants are generally ineffective for this kind of deafness because of the loss of continuity in the auditory nerve after tumor removal. The first auditory brainstem implant (ABI) in such a patient was performed in 1979 at the House Ear Institute, and this individual continues to benefit from electrical stimulation of the cochlear nucleus complex.

Growth of postoperative remnants of unilateral vestibular nerve schwannoma: role of the vestibular ganglion.

Histopathological examination of seven temporal bones from patients who underwent a removal of vestibular nerve schwannomas by the translabyrithine or middle fossa approaches has demonstrated small tumor remnants that failed to grow as long as 25 years after surgery. In spite of the high incidence of residual tumors, the clinical recurrence rate of tumors operated at our institution by the translabyrinthine or middle fossa approaches is low (0.3%).

Hearing preservation in patients with vestibular schwannomas with sudden sensorineural hearing loss.

Objective: We evaluated hearing outcomes in patients with sudden hearing loss and vestibular schwannoma who underwent a hearing preservation operation for tumor resection in an effort to determine whether a history of sudden sensorineural hearing loss has an impact on subsequent hearing preservation surgery.

Methods: Retrospective chart review of 45 patients operated between 1990 and 1998. Patients were divided into "Recovery" (n = 22) and "No Recovery" (n = 23) groups based on preoperative hearing recovery.

The transcochlear approach revisited.

Objective: To evaluate the indications for, techniques used in, and patient outcomes after surgery with the transcochlear approach in the treatment of petroclival tumors.

Methods: Retrospective review of 24 cases between 1985 and 1995 at the House Ear Clinic (Los Angeles, CA, U.S.

Early proactive management of vestibular schwannomas in neurofibromatosis type 2.

Objective: The treatment of patients with neurofibromatosis Type 2 has always been challenging for neurosurgeons and neurotologists. Guidelines for appropriate management of this devastating disease are controversial.

Methods: A retrospective study of 28 patients with neurofibromatosis Type 2 who underwent 40 middle fossa craniotomies for excision of their acoustic tumors is reported.

Brainstem electronic implants for bilateral anacusis following surgical removal of cerebello pontine angle lesions.

The multichannel auditory brainstem implant (ABI) has been used successfully to treat deafness in individuals with neurofibromatosis type II. The device has been implanted in nearly 150 recipients worldwide, and clinical trials with the device are approaching completion. The implantation and fitting of the multichannel ABI differ significantly from cochlear implantation, and the processes are illustrated in a series of case studies.

Twenty-year report of the first auditory brain stem nucleus implant.

We present the 20-year case report of an auditory implant placed on the dorsal cochlear nucleus with long-term electrical stimulation in a patient with neurofibromatosis 2. The patient has continued to use her implant daily for 20 years, and it has greatly enhanced her quality of life. There have been no adverse sequelae.

Restoration of hearing with an auditory brainstem implant in a patient with neurofibromatosis type 2--case report.

A 25-year-old male with neurofibromatosis type 2 had hearing restored with an auditory brainstem implant (ABI) after removal of an acoustic schwannoma. The ABI allows the patient to discern many different environment sounds and is a significant adjunct to lip-reading, enabling conversation with people who have clear pronunciation without the necessity for writing.

Prognostic factors for hearing preservation in vestibular schwannoma surgery.

Objective: To determine whether prognostic indicators for hearing preservation could be identified in patients with vestibular schwannoma undergoing middle fossa craniotomy resection.

Study Design: Prospective case review.

Setting: Private practice tertiary referral center.

Coexpression of neurotrophic growth factors and their receptors in human facial motor neurons.

Neuronal development and maintenance of facial motor neurons is believed to be regulated by neurotrophic growth factors. Using celloidin-embedded sections, we evaluated immunoreactivity of 11 neurotrophic factors and their receptors in facial nuclei of human brain stems (4 normal cases, and 1 from a patient with facial palsy and synkinesis). In the normal subjects, positive immunoreactivity of the growth factor neurotrophin-4 and acidic fibroblast growth factor (aFGF) was observed in facial motor neurons, as was positive immunoreactivity against ret, the receptor shared by glial cell line-derived neurotrophic factor and neurturin.

Report of 190 consecutive cases of large acoustic tumors (vestibular schwannoma) removed via the translabyrinthine approach.

Object: The choice of approach for surgical removal of large acoustic neuromas is still controversial. The authors reviewed the results in a series of patients who underwent removal of large tumors via the translabyrinthine approach.

Methods: The authors conducted a database analysis of 190 patients (89 men and 101 women) with acoustic neuromas 3 cm or greater in size.

Hearing preservation in neurofibromatosis type 2.

Objective: The aim of the study was to provide a clinical review of the middle fossa approach for hearing preservation in patients with neurofibromatosis type 2 (NF2).

Study Design: The study design was a prospective case review.

Setting: The study was conducted at a private practice tertiary neurotologic referral center.