William E. Hitselberger

Bio: William E. Hitselberger is an academic researcher from University of Southern California. The author has contributed to research in topics: Cerebellopontine angle & Acoustic neuroma. The author has an hindex of 36, co-authored 91 publications receiving 4207 citations. Previous affiliations of William E. Hitselberger include St. Vincent's Health System.

Abnormal myelograms in asymptomatic patients.

Abstract: I N THE evaluation of the patient with back, neck, arm, or leg pain, great reliance has been placed on the results of myelography. Occasionally, difficulties arise in the correlation of the results of this study with the clinical examination. The myelogram may be normal in the face of a clear-cut clinical syndrome, or defects in the positive contrast column may be found at levels other than those thought to be involved. Accordingly, more information has been needed relative to the incidence of myelographic abnormalities in the asymptomatic patient. This paper reports the incidence of myelographic abnormalities in 300 patients who were studied by posterior fossa myelography to establish a diagnosis of acoustic tumor. Myelograms of the spinal axis were obtained even though these patients had no symptoms of cervical or lumbar nerve root compression at the time of the examination.

The transcochlear approach to the skull base.

Abstract: A new approach to tumors of the skull base is described. This approach is accomplished by forward extension of the translabyrinthine opening into the cerebellopontine angle. The facial nerve is mobilized in the temporal bone from the stylomastoid foramen to its entrance into the internal auditory canal. Having removed the barrier of the facial nerve, additional bone removal can be carried forward to the internal carotid artery, which now becomes the forward limit for temporal bone resection. The access attained through this exposure allows removal of tumors arising from the petrous tip, as well as tumors arising directly from the clivus. We provide the case histories of four patients in whom this approach was successfully used in removal of skull base tumors.

Multichannel auditory brainstem implant: update on performance in 61 patients

Abstract: 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. In 1992, an advanced multichannel ABI was developed and a series of patients with NF2 received this implant to study the safety and efficacy of the device. Methods. At the time of first- or second-side VS removal, patients received an eight-electrode array applied to the surface of the cochlear nucleus within the confines of the lateral recess of the fourth ventricle. The device was activated approximately 6 weeks after implantation, and patients were tested every 3 months for the 1st year after the initial stimula...

Prognostic factors for hearing preservation in vestibular schwannoma surgery.

Abstract: 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. Patients: 333 patients with serviceable hearing and vestibular schwannoma resected by middle fossa craniotomy from 1992 to 1998. Main Outcome Measures: Potential prognostic indicators, including tumor size and nerve of origin, preoperative pure-tone average, speech discrimination, distortion product otoacoustic emission testing, age, auditory brainstem response (ABR), and electronystagmography. Results: Postoperative hearing near preoperative levels was attained in 167 patients (50%), with an American Academy of Otolaryngology-Head and Neck Surgery Class A hearing result in 33% and a Class B result in 26%. Comparison of potential prognostic indicators between groups with hearing preserved and the group with no measurable hearing revealed significant differences in preoperative hearing, ABR, and tumor origin data. Better preoperative hearing, shorter intraaural wave V latency, shorter absolute wave V latency, and superior vestibular nerve origin were associated with higher rates of hearing preservation. Conclusions: Preoperative hearing status, ABR, and intraoperative tumor origin data were shown to be of value as prognostic indicators.

Auditory Brainstem Implant: I. Issues in Surgical Implantation:

Abstract: Most patients with neurofibromatosis type 2 (NF2) are totally deaf after removal of their bilateral acoustic neuromas. Twenty-five patients with neurofibromatosis type 2 have been implanted with a brainstem electrode during surgery to remove an acoustic neuroma. The electrode is positioned in the lateral recess of the fourth ventricle, adjacent to the cochlear nuclei. The present electrode consists of three platinum plates mounted on a Dacron mesh backing, a design that has been demonstrated to be biocompatible and positionally stable in an animal model. Correct electrode placement depends on accurate identification of anatomic landmarks from the translabyrinthine surgical approach and also on intrasurgical electrophysiologic monitoring. Some tumors and their removal can result in significant distortion of the brainstem and surrounding structures. Even in the absence of identifiable anatomic landmarks, electrode location can be adjusted during surgical placement to find the location that maximizes the auditory evoked response and minimizes activation of other monitored cranial nerves. Stimulation of the electrodes produces auditory sensations in most patients, with results similar to those of single-channel cochlear implants. A coordinated multidisciplinary team is essential for successful application of an auditory brainstem implant.

Guidelines for the Early Management of Patients With Acute Ischemic Stroke A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

Abstract: Background and Purpose—The authors present an overview of the current evidence and management recommendations for evaluation and treatment of adults with acute ischemic stroke. The intended audienc...

Abnormal magnetic-resonance scans of the lumbar spine in asymptomatic subjects. A prospective investigation

Abstract: We performed magnetic resonance imaging on sixty-seven individuals who had never had low-back pain, sciatica, or neurogenic claudication. The scans were interpreted independently by three neuro-radiologists who had no knowledge about the presence or absence of clinical symptoms in the subjects. About one-third of the subjects were found to have a substantial abnormality. Of those who were less than sixty years old, 20 per cent had a herniated nucleus pulposus and one had spinal stenosis. In the group that was sixty years old or older, the findings were abnormal on about 57 per cent of the scans: 36 per cent of the subjects had a herniated nucleus pulposus and 21 per cent had spinal stenosis. There was degeneration or bulging of a disc at at least one lumbar level in 35 per cent of the subjects between twenty and thirty-nine years old and in all but one of the sixty to eighty-year-old subjects. In view of these findings in asymptomatic subjects, we concluded that abnormalities on magnetic resonance images must be strictly correlated with age and any clinical signs and symptoms before operative treatment is contemplated.

Magnetic resonance imaging of the lumbar spine in people without back pain.

Abstract: Background The relation between abnormalities in the lumbar spine and low back pain is controversial. We examined the prevalence of abnormal findings on magnetic resonance imaging (MRI) scans of the lumbar spine in people without back pain. Methods We performed MRI examinations on 98 asymptomatic people. The scans were read independently by two neuroradiologists who did not know the clinical status of the subjects. To reduce the possibility of bias in interpreting the studies, abnormal MRI scans from 27 people with back pain were mixed randomly with the scans from the asymptomatic people. We used the following standardized terms to classify the five intervertebral disks in the lumbosacral spine: normal, bulge (circumferential symmetric extension of the disk beyond the interspace), protrusion (focal or asymmetric extension of the disk beyond the interspace), and extrusion (more extreme extension of the disk beyond the interspace). Nonintervertebral disk abnormalities, such as facet arthropathy, were also d...

The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2.

Abstract: Objective. —Neurofibromatosis 1 and neurofibromatosis 2 are autosomal dominant genetic disorders in which affected individuals develop both benign and malignant tumors at an increased frequency. Since the original National Institutes of Health Consensus Development Conference in 1987, there has been significant progress toward a more complete understanding of the molecular bases for neurofibromatosis 1 and neurofibromatosis 2. Our objective was to determine the diagnostic criteria for neurofibromatosis 1 and neurofibromatosis 2, recommendations for the care of patients and their families at diagnosis and during routine follow-up, and the role of DNA diagnostic testing in the evaluation of these disorders. Data Sources. —Published reports from 1966 through 1996 obtained by MEDLINE search and studies presented at national and international meetings. Study Selection. —All studies were reviewed and analyzed by consensus from multiple authors. Data Extraction. —Peer-reviewed published data were critically evaluated by independent extraction by multiple authors. Data Synthesis. —The main results of the review were qualitative and were reviewed by neurofibromatosis clinical directors worldwide through an Internet Web site. Conclusions. —On the basis of the information presented in this review, we propose a comprehensive approach to the diagnosis and treatment of individuals with neurofibromatosis 1 and neurofibromatosis 2.

Back pain and sciatica.

Abstract: LOW back pain is usually a self-limiting symptom, but it costs at least $16 billion each year1 , 2 and disables 5.4 million Americans.3 The fact that a benign physical condition has such an importa...