Inflammatory meningiomas of the internal auditory canals.
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Adult↗
Biomedical subjects
W E Hitselberger
Publications and source records attributed to W E Hitselberger.
Retrolabyrinthine vestibular nerve section: evaluation of technical modification in 143 cases.
Selective vestibular nerve section is effective in relieving intractable vertigo while preserving hearing. Histologic study demonstrated overlap of the cochlear and vestibular fibers at the cochleovestibular cleavage plane within the posterior fossa. In the hopes of improving surgical results by sectioning these overlapping vestibular fibers, the technique of sectioning the vestibular division of the eighth nerve was modified to include a small portion of the cochlear division. We have evaluated 143 cases of retrolabyrinthine vestibular nerve section in which this technical modification was employed. A patient questionnaire was used to examine control of vertigo as well as changes in tinnitus, unsteadiness, and disability. Hearing preservation and incidence of complications were also reviewed. Resolution or improvement of vertigo occurred in 93 percent of Menièré's cases and 74 percent of non-Menièré's cases as compared to 97 percent and 68 percent, respectively, in the pre-1986 series.
Adult↗
Extended middle fossa and retrolabyrinthine approaches in acoustic neuroma surgery: case reports.
Hearing conservation surgery for small acoustic neuromas is well accepted. At present, two approaches are primarily used: the suboccipital and the middle fossa. The middle fossa approach to the internal auditory canal has the advantage of using bony landmarks to identify and protect the facial nerve. Because of anatomic constraints presented by the superior semicircular canal however, its uses are limited to intracanalicular tumors or tumors protruding only slightly into the cerebellopontine angle. By extending the approach through the superior semicircular canal, a wide access to the cerebellopontine angle can be safely obtained. In this study three procedures, two through the superior semicircular canal and one through the posterior semicircular canal, were utilized for hearing conservation surgery. By immediately sealing off the canal ends, hearing preservation was accomplished in two out of three of these cases. The dictum that labyrinthine opening invariably leads to anacusis should be reconsidered. By utilizing approaches through the semicircular canal, it is possible that morbidity from this surgery may be reduced.
Cerebellar Neoplasms↗
Acoustic tumors: effect of surgical removal on tinnitus.
Tinnitus is common in patients with acoustic tumors and may be the initial symptom leading to diagnosis. We might anticipate that tumor removal would alleviate preoperative tinnitus. However, few have studied this systematically. Further, the effect of tumor removal in those with no preoperative tinnitus has rarely been examined. In this study, a questionnaire was sent retrospectively to patients who had undergone surgical removal of an acoustic tumor, addressing the characteristics of tinnitus, and asking whether surgery had directly affected tinnitus. A total of 134 questionnaires were returned. Those who indicated preoperative tinnitus tended to show small but statistically significant improvements in the perceived severity of the tinnitus after surgery, although the symptom rarely resolved entirely. Those with no preoperative tinnitus have an approximately 50 percent chance of developing it following surgery.
Adult↗
The treatment of small acoustic tumors: now or later?
Prior to the advent of microneurosurgery, the operative mortality for acoustic tumor removal was high and management often consisted of observation until sufficient symptoms warranted removal. The treatment of these tumors has evolved, and recent introduction of gadolinium-enhanced magnetic resonance imaging (MRI) allows the diagnosis of very small intracanalicular acoustic tumors before hearing has been significantly affected. For such tumors, some surgeons advocate the premicrosurgical philosophy of observation rather than removal. Our results of small acoustic tumor removal with attempt at hearing preservation were reviewed. From 1961 to June 1989, 39 acoustic tumors 0.5 cm or less were removed by the middle fossa approach. Measurable hearing was preserved in 67%, and facial function 1 year postoperatively was normal or nearly normal in 97%. There was no other permanent operative morbidity. Given our results, early surgical removal of small acoustic tumors is advocated.
Adolescent↗
Auditory brain stem implant: effect of tumor size and preoperative hearing level on function.
The auditory brain stem implant is an investigational device designed to provide hearing sensations to patients without functioning auditory nerves. We analyzed results from 17 implants in 15 patients to determine if tumor size or preoperative hearing level might be related to proper device function. We found no significant correlation between preoperative hearing level or tumor size and device function. We also found no significant correlation between preoperative hearing level and tumor size in these 15 patients.
Adolescent↗
Cochlear nucleus anatomy related to central electroauditory prosthesis implantation.
The central electroauditory prosthesis is now used to stimulate the cochlear nuclei to obtain auditory perception in patients with bilateral cochlear nerve transection who are undergoing bilateral acoustic tumor removal. In this study, we used fixed cadaver specimens to identify visible landmarks for accurate placement of the central electroauditory prosthesis through a combined suboccipital-translabyrinthine opening. Histologic features of the regions of probable implantation of the central electroauditory prosthesis were also investigated. We found that the following landmarks might have surgical significance: (1) the tenia of the inferior velum of the fourth ventricle, which crosses the surface of the ventral cochlear nucleus and the vestibulocochlear nerve; (2) the angle between the vestibulocochlear and glossopharyngeal nerves; and (3) the foramen of Luschka. It is suggested that an incision be made in the tenia for insertion of the prosthesis into the lateral recess and eventual placement on the ventral cochlear nucleus surface. To study regions of potential stimulation, we injected ink into different sites on the exposed surface of the cochlear nuclei. We then histologically examined neuronal populations adjacent to the sites. We found that a portion of the ventral cochlear nucleus localized within the lateral recess might be the most appropriate location for placement of the central electroauditory prosthesis.
Cochlea↗
Hearing preservation after acoustic tumor removal: long-term results.
This report examines the durability of preserved postoperative hearing in 25 middle fossa acoustic tumor patients with a minimum follow-up of 3 years. The mean follow-up time for this group was more than 8 years, with a maximum of almost 20 years. The initial postoperative audiogram was compared to the most recent audiogram for each patient, with change in the nonoperated ear serving as the control. Fourteen of the patients (56%) had a significant loss of the preserved hearing in the operated ear over time. The mean loss of speech discrimination was 25%, and the mean loss of speech reception threshold was 12 dB. Only one of the 14 patients had a similar loss in the contralateral ear. No recurrent tumors were identified. Good preoperative hearing is an obvious criterion for selection of candidates for hearing preservation surgery. Results of this study emphasize that a good initial postoperative hearing level is necessary to offset the potential deterioration of hearing that may occur over time.
Adolescent↗
Middle fossa decompression of the internal auditory canal in acoustic neuroma surgery: a therapeutic alternative.
Unilateral acoustic neuromas in only-hearing ears and bilateral acoustic neuromas (NF-2) are separate entities, but both pose a common problem because surgical removal has the potential to leave the patient totally deafened. A middle fossa decompression of the internal auditory canal (IAC) was performed in 8 patients (5 with NF-2 tumors and 3 with neuromas in an only-hearing ear). In 5 of the 8, the speech discrimination scores at the 6-month follow-up were better than preoperative scores. After 6 months, however, hearing regressed at variable rates. Although not a definitive therapeutic treatment, decompression of the IAC appears to improve and perhaps prolong useful hearing, which gains valuable time for rehabilitation. Rigid follow-up by computed tomography scans or magnetic resonance imaging is essential.
Adult↗
Sex hormone receptors in acoustic neuromas.
We performed quantitative assays for estrogen, progesterone, and testosterone receptors in 19 acoustic neuroma specimens from ten men and nine women. No patient received preoperative or intraoperative glucocorticoids, mineralocorticoids, or sex hormones. All tumors were unilateral and removed by the translabyrinthine approach. No tumor specimen was positive for estrogen or testosterone receptors. Three of ten men and seven of nine women had tumors positive for progesterone receptors (10 fmol/mg cytosol protein or greater). This between-sex difference was of borderline significance by the Mann-Whitney U test (p = 0.08). This finding indicates the need for further investigations of endocrinologic therapy as a possible treatment of acoustic neuromas.
Female↗
Acoustic tumor surgery. Prognostic factors in hearing conversation.
Preoperative selection criteria for hearing conservation surgery in patients with acoustic tumors continues to be unresolved. The level of hearing that is worth saving is still debatable. However, most acoustic tumor surgeons agree that hearing preservation is less likely the larger the tumor. We reviewed the results of 106 middle fossa acoustic tumor removals with attempted hearing preservation. Measurable postoperative hearing remained in 59% of 97 cases analyzed for postoperative hearing results. Tumor size, preoperative auditory brain-stem response, and preoperative electronystagmography were found to be useful in predicting successful postoperative hearing preservation. We found no correlation between the level of preoperative hearing and our ability to preserve measurable postoperative hearing. A new classification system is proposed for reporting hearing results after acoustic tumor surgery. It is based on functional hearing results and we believe it is simpler than previously proposed systems.
Audiometry↗
The neural dissector.
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Equipment Design↗
Middle fossa acoustic tumor surgery: results in 106 cases.
Although the middle cranial fossa approach has been used less frequently in recent years than in the past, it continues to be a useful technique for the removal of small acoustic tumors with possible hearing preservation. The approach provides complete exposure of the contents of the internal auditory canal, thus allowing positive facial nerve identification and facilitating total tumor removal. This paper reports the results of 106 middle fossa acoustic tumor removals over a 25-year period. Measurable postoperative hearing remained in 59% of cases. In 89% of cases, normal or near-normal postoperative facial nerve function was obtained. Total tumor removal was achieved in 98% of cases. Preoperative selection criteria are discussed, and postoperative complications are reported.
Adult↗
Retrolabyrinthine vestibular neurectomy: a reevaluation.
Selective vestibular neurectomy is considered an effective means of relieving intractable vertigo while preserving hearing. In order to determine the effectiveness of the retrolabyrinthine approach to selective vestibular neurectomy, we evaluated 161 patients who underwent vestibular neurectomy between April 1981 and September 1985. Questionnaire responses indicated that 97% of the Meniere's disease patients and 68% of the non-Meniere's disease patients experienced a substantial improvement or resolution of their vertiginous symptoms. Hearing was maintained within 10 dB of the preoperative level in the majority of the patients. Neurological complications were limited to 2 cases of meningitis which resolved with medical therapy, 7 cases of cerebral spinal fluid leaks, and 3 cases of complete sensorineural hearing loss. Based on this review, we concluded that retrolabyrinthine vestibular neurectomy continues to be a safe and effective approach to relieve ear-related vertigo.
Adult↗
Vertigo caused by basilar artery compression of the eighth nerve.
Vascular compression syndromes in the posterior cranial fossa have become well described clinical entities, especially for the fifth and seventh cranial nerves. Jannetta has proposed vascular compression of the eighth nerve as the etiology of hearing loss, tinnitus, and vertigo in some patients. The case that follows illustrates a clear-cut example of vestibular symptoms arising from vascular compression of the eighth nerve. The patient involved had disabling peripheral vertigo refractory to medical management. Magnetic resonance imaging documented a tortuous basilar artery compressing the eighth nerve on the involved side. This was confirmed at surgery, and a selective section of the vestibular nerve provided complete relief of disabling symptoms and preservation of hearing. The authors describe the details of this case and the enigma of eighth nerve symptoms due to vascular compression.
Basilar Artery↗
Surgical accessibility of the cochlear nuclear complex in man: surgical landmarks.
Patients deafened by bilateral acoustic tumors or by transections of both cochlear nerves are excluded as candidates for cochlear implantation. These patients require more proximal stimulation of the auditory pathway. One potential area for such stimulation is the cochlear nuclear complex (CNC) in the lateral recess of the fourth ventricle. If animal studies establish the safety and efficacy of such stimulation, electrical stimulation of the human cochlear nuclear complex may become an accepted treatment modality for this select group of patients. Such implantation requires that the surgeon accurately locate the cochlear nuclear complex without destruction of vital surrounding neural and vascular structures. With ten fresh human brains, oriented for a translabyrinthine approach, we determined key anatomical landmarks to the exposed surface of the CNC on both sides of each brain. Using a combination of anatomical landmarks--including the flocculus, eighth nerve root, choroid plexus, and taenia--we located the cochlear nuclear complex (without disruption of surrounding neural or vascular structures) and marked it with colloidal carbon. Access to the CNC was obtained in all 20 specimens, and histologic sections confirmed the carbon marker in the CNC in 19 of 20 specimens.
Cochlea↗
Acoustic tumor management in senior citizens.
We reviewed records of 116 consecutive acoustic tumor surgery patients aged 65 and older during the 10 years ending in 1984. One hundred six had total removal. Ninety-four (81%) had no intraoperative complications and 66 (57%) had no postoperative complications. Only one patient, who had previously undergone partial removal elsewhere, died. Because tumors grow at 2 mm per year, and because elderly patients can expect to live up to 18 more years, we recommend planned total removal of an acoustic tumor as the management of choice for senior citizens in good health. We feel that the advantages of immediate surgery outweigh the risks of delayed surgery when age is advanced, the tumor is enlarged, and general health may be declining.
Age Factors↗
Early detection of small bilateral acoustic tumors.
Bilateral acoustic tumors are one of the most difficult problems in acoustic tumor surgery. Total tumor removal with preservation of hearing has seldom been achieved in the past. Recently, hearing has been successfully preserved if the tumors are small when removed. We present the case of a child with a family history of von Recklinghausen's disease associated with bilateral acoustic tumors. A high index of suspicion of bilateral tumors and a thorough work-up resulted in the early diagnosis of small tumors. The tumors were removed with preservation of normal hearing.
Adolescent↗