Histopathological features of a cochlear implant and otogenic meningitis in Mondini dysplasia.

The temporal bones of a 6-year-old boy with a cochlear implant for profound hearing loss associated with Mondini dysplasia were studied histopathologically. Despite having severe Mondini dysplasia, he was able to detect sound with the implant. On histological examination of the temporal bone, he had more than 10000 spiral ganglion cells. Histopathological changes in the inner ear associated with the cochlear implant were minimal. Patients with severe Mondini dysplasia and profound hearing loss may, therefore, benefit from cochlear implantation. In the contralateral ear, the patient had suppurative labyrinthitis and meningitis associated with chronic otitis media. Histopathological evidence of inflammatory necrosis of the round window membrane was consistent with suppurative labyrinthitis secondary to otitis media.

Evaluation of the nonorganic hearing loss suspect.

OBJECTIVE: To examine the utility of distortion-product otoacoustic emissions (DPOAEs) in the assessment of the nonorganic suspect because DPOAE analysis constitutes an objective test of hair-cell function that yields audiometriclike data. STUDY DESIGN: Retrospective study of clinical findings. SETTING: Audiology outpatient clinic of our university's medical center. PATIENTS: The study cohort comprised 30 patients who presented with a profile of suspicion for nonorganic hearing loss. Most cases were found, with the aid of DPOAE testing, to be nonorganic or to have nonorganic overlays to organic hearing loss. INTERVENTIONS: Interventions were diagnostic only. MAIN OUTCOME MEASURES: Observed audiometric findings and changes thereof. RESULTS: Statistically significant decreases in thresholds occurred in subgroups of those cases deemed to be truly nonorganic in origin. CONCLUSIONS: Especially considering test efficiency, the results support the inclusion of DPOAE analysis in the diagnostic management of the suspect-nonorganic patient.

Intratympanic gentamicin therapy for Ménière's disease.

OBJECTIVE: To evaluate the efficacy and toxicity of intratympanic gentamicin therapy for the treatment of Meniere's disease. STUDY DESIGN: We compared retrospective case series with historical controls. SETTING: A tertiary referral center--the ambulatory clinic at The University of Pittsburgh Medical Center. PATIENTS: The study consisted of 28 patients with Meniere's disease who failed conventional medical therapy and were offered gentamicin treatment or surgical intervention. Patients had to be followed for at least 2 years to be eligible for review. INTERVENTION: Intratympanic gentamicin solution injections were given by serial titration to the involved ear on a weekly or biweekly schedule. MAIN OUTCOME MEASURES: Adhering to the American Academy of Otolaryngology--Head and Neck Surgery 1985 criteria for reporting treatment results in Meniere's disease, the hearing status, control of vertigo, and disability scores using intratympanic gentamicin therapy were reported and compared with historical controls. RESULTS: Complete or substantial control of vertigo was achieved in 91% of patients. Hearing loss occurred in approximately one third of patients. Historically, similar hearing loss occurs in patients who were treated successfully, either medically or surgically. Ototoxicity (high frequency hearing loss) was more likely to be seen in patients with pre-treatment 8,000 Hz hearing thresholds better than 65dB. CONCLUSIONS: Intratympanic gentamicin therapy given by serial titration injections provides significant control of vertigo without the significant cost and potential morbidity of a more invasive surgical procedure.

Role of chemical labyrinthectomy in the treatment of Meniere's disease.

Medical management of Meniere's disease is successful in approximately 70% of patients. Surgical intervention is the treatment option when medication fails. Middle ear installation of aminoglycosides provides significant control of vertigo. This article addresses the role of aminoglycoside ablation of vestibular function in Meniere's disease.

Localizing retrocochlear hearing loss.

PURPOSE: The origin of acute/sudden hearing loss is multifactorial. The association of vestibular symptoms does not necessarily isolate the pathologic condition to the inner ear. The audiogram provides a screen for differentiating conductive from sensorineural loss but often fails to provide more localizing information. METHODS: Three unusual patients with a variety of retrocochlear presentations of hearing loss are presented. Along with conventional auditory brainstem response (ABR) testing, newer auditory tests, including otoacoustic emissions and three-dimensional ABR analysis, can facilitate site-of-lesion testing. Magnetic resonance imaging (MRI) also provides graphic documentation for sources of retrocochlear hearing loss. RESULTS: One patient had gamma-knife treatment of an arteriovenous malformation, incurring a localised lesion to the inferior colliculus contralateral to the side of hearing loss. This effectively eliminated wave V, as confirmed by three-dimensional ABR analysis. A second patient with human immunodeficiency virus developed sudden complete hearing loss with retained otoacoustic emissions, confirming a retrocochlear lesion. A third patient with acute otitis media with sudden hearing loss and vertigo had an abnormal ABR and "mass lesion" on MRI. Hearing subsequently returned to normal, as did a repeated scan. CONCLUSIONS: The unique aspects of each case of retrocochlear hearing loss and the applied auditory electrophysiologic tests are reviewed.

Use of nimodipine in the medical treatment of Menière's disease: clinical experience.

PURPOSE: Nimodipine is a highly lipophilic, centrally acting calcium channel blocker. It is similar in action to flunarizine, which has been studied for use in the medical treatment of Menière's disease. METHODS: Nimodipine was offered to patients with Menière's disease for whom first-line medical management failed (dietary restrictions and diuretics or vestibular suppressants). RESULTS: Our preliminary clinical experience using nimodipine in 12 patients with Menière's disease from December 1992 until March 1995 resulted in successful control of vertigo and hearing improvement or stabilization in seven (58%) of 12 patients. When hearing stabilization was not considered, eight (67%) patients had vertigo satisfactorily controlled (AAOO class A, B, or C). The four (33%) patients whose vertigo symptoms persisted despite treatment with nimodipine (AAOO class D) were surgically treated with successful vertigo control. Nimodipine was discontinued in one class D patient because of gastrointestinal intolerance. CONCLUSIONS: Nimodipine provides an alternative successful means for medical management of Menière's disease.

The efficacy of tympanic electrocochleography in the diagnosis of endolymphatic hydrops.

Electrocochleography (ECoG), an objective electrophysiologic test, is useful in the clinical diagnosis of endolymphatic hydrops. The purpose of this study was further to define the role of ECoG in the diagnosis of this disease. A retrospective chart review of 100 patients undergoing tympanic ECoG was undertaken comparing symptoms, degree of hearing loss, duration of disease, and diagnosis with ECoG results. The apparent sensitivity and specificity of ECoG in the diagnosis of endolymphatic hydrops were determined to be 57% and 94%, respectively. Three of 30 positive ECoG results were falsely positive. Fluctuating hearing loss and the degree of hearing loss (< 40 dB) and duration of disease (< 48 months) were statistically significant in predicting positive ECoG results. We conclude that a positive ECoG result is helpful in objectively confirming the disease. However, a negative result does not rule out hydrops.

Imaging of ossicular prostheses.

The prostheses available for reconstruction of the ossicular chain have expanded to include a variety of synthetic materials. Hydroxyapatite contains the inorganic constituents found in human living bone and is currently being incorporated into many new prostheses. This study demonstrates the computed tomography and magnetic resonance image characteristics of eight middle ear prostheses, a block of dense hydroxyapatite, and a human incus. Imaging of ossicular prostheses is more informative with computed tomography.

Hydroxyapatite cement: a new method for achieving watertight closure in transtemporal surgery.

Transtemporal approaches to the petrous apex and CP angle are standard procedures in the armamentarium of the neurotologist. In the majority of these cases, it is not possible to achieve a watertight suture closure of the dura following the procedure. Subsequently, cerebrospinal fluid leakage and potential meningitis are among the most troublesome complications for both patient and surgeon. Recent use of calcium phosphate cement (hydroxyapatite [HA]) has proved efficacious in animal studies and is now being used to close cranial defects in several medical centers, as part of an FDA-IDE study in human subjects. The use of this material is described in 11 neurotologic procedures. It is believed that hydroxyapatite cement (HAC) will become a standard tool in the management of cranial base and temporal bone defects following surgery.

Results of revision stapedectomy for conductive hearing loss.

Revision stapedectomy operations performed over a 13-year period (1977 to 1990) for a conductive hearing loss are reviewed in terms of intraoperative findings and hearing results. All operations were performed in a conventional manner without use of laser techniques. A management algorithm based on intraoperative findings is described. Results are compared with previously reported series. The 66 cases include 20 males and 46 females, ranging in age from 8 to 73 years. Mean time between original and revision stapedectomy was 12.5 years. Prostheses encountered at time of revision included wireloop (29), Robinson (18), polyethylene (14), other (3), and two were not found. The most common cause of failure was displacement of the prosthesis. Incus erosion was found in 48% of wireloops, 35% of polyethylene, and only 11% of the Robinson prostheses. Revision resulted in closure of the pure-tone average (PTA) air-bone gap to within 10 dB in 46% and to within 15 dB in 76%. Sensorineural hearing loss (> 10 dB) occurred in 5 cases (7.6%), and a decline in speech discrimination (> 10%) occurred in 17%. Three of four cases requiring drillout had gap closure to within 10 dB. Findings suggest that our management technique produces results comparable to other large reported series. Drillout at the time of revision can be recommended.

Hypercoagulability in otologic patients.

INTRODUCTION: Three patients with otologic disorders developed complications related to hypercoagulability. This report was prepared to increase the awareness among otolaryngologists of the diagnosis and management of hypercoagulable states, and to encourage expert consultation when indicated. MATERIALS AND METHODS: One patient with dural venous sinus thrombosis complicating an otitis media, one patient with a large glomus jugulare tumor, and one patient with a sudden sensorineural hearing loss were treated by the otolaryngology service. Suspicious thromboembolic events were evaluated by the hematology service, and appropriate anticoagulative therapy was recommended. RESULTS: One patient with an inherited hypercoagulopathy and two patients with acquired hypercoagulopathies were treated for otologic problems. Two of the patients were stabilized and discharged on life-long anticoagulation therapy. The third patient, in spite of intensive medical and surgical support, eventually succumbed to complications to which an acquired hypercoagulable state made a significant contribution. Expert consultants made the hematologic diagnoses and treatment recommendations. CONCLUSION: Otolaryngologists should be aware that hypercoagulable states may now be more accurately diagnosed and characterized, and that thorough investigation of thromboembolic events may affect treatment decisions.

Facial nerve function following cerebellopontine angle surgery: prognostic value of electroneurography.

Preoperative counseling of patients, regarding facial nerve function following cerebellopontine angle (CPA) surgery, has remained a difficult task. Facial nerve electroneurography (ENoG) or evoked electromyography can detect subclinical neural degeneration. This test was used in 44 patients undergoing CPA surgery, and facial nerve function was followed postoperatively. A normal preoperative ENoG study appeared to predict an 81 percent and 84 percent chance of good (House grade I-II) early and late postoperative facial function, respectively. An abnormal test is not as reliable. The relation of preoperative ENoG results with tumor size and tumor adherence to the facial nerve is investigated. Electroneurography appears to be a useful preoperative test when counseling patients regarding facial function following CPA surgery.

Facial nerve function following cerebellopontine angle surgery: prognostic value of intraoperative thresholds.

Intraoperative stimulation of the facial nerve during surgery of the cerebellopontine angle greatly aids the surgeon in identification of the nerve. The preservation of the ability to stimulate the facial nerve, at the brain stem following tumor removal, has been shown to correlate with good postoperative facial outcome. Thresholds of facial nerve stimulation recorded in our series, using constant voltage stimulation, showed statistically significant relevance to facial nerve outcome. When the difference between thresholds before and after tumor removal was 0.2 V or less or when the threshold after tumor removal was less than or equal to 0.2 V, a good postoperative facial outcome could be expected. This paper discusses the relevance of stimulation threshold prior to tumor removal to the size of tumor.

Off-vertical axis rotational responses in patients with unilateral peripheral vestibular lesions.

Off-vertical axis rotation (OVAR) stimulates the otolith organs in a manner that is suitable for assessment of the otolith-ocular reflex. To further assess the potential clinical usefulness of OVAR, the eye movement responses of seven patients with surgically confirmed unilateral peripheral vestibular lesions were compared with the eye movement responses of a group of age-matched, healthy, asymptomatic control subjects. Patients and controls were tested with constant velocity rotations that followed a brief period of angular acceleration (velocity trapezoid) using either earth-vertical axis (EVA) rotation or OVAR. Both EVA and OVAR sinusoidal velocity profiles were also performed. Results indicated that each patient had 1) an asymmetric OVAR response, ie, a bias component whose direction was opposite normal when rotating toward the lesioned ear, and 2) a normal modulation component. Population data suggested that patients had 1) a more rapid decay of response than normal subjects during OVAR velocity trapezoids, 2) an increased phase lead as compared to normal subjects during sinusoidal OVAR, and 3) like normal subjects, a less rapid decay of response during OVAR velocity trapezoids than during EVA rotational velocity trapezoids. Taken together, these findings suggest that patients with unilateral peripheral vestibular deficits have abnormal otolith-ocular and semicircular canal-ocular reflexes but that a single labyrinth appears to provide an otolithic signal sufficient for qualitatively normal semicircular canal-otolith interaction.

Preservation of vestibular nerves in surgery of the cerebellopontine angle: effect on hearing and balance function.

INTRODUCTION: Small tumors of the cerebellopontine angle (CPA) can frequently be removed with preservation of the auditory and the vestibular portion of the eighth cranial nerve. This study was undertaken to estimate the effect of vestibular nerve preservation on both balance and hearing following surgery. MATERIALS AND METHODS: A retrospective study of all cases of CPA lesions between 1987 and 1991 was undertaken. This identified 11 patients in whom either the superior and/or inferior vestibular nerves were preserved. This included eight acoustic neuromas and three meningiomas. The retrosigmoid approach and total tumor extirpation was undertaken in all cases. Patients undertook a vestibular questionnaire, audiometric testing, and evaluation of vestibulo-ocular responses preoperatively and postoperatively. Additionally, static and dynamic platform posturography was performed postoperatively in 9 of 11 patients. RESULTS: Follow-up ranged from 6 to 44 months. Of the eight patients with acoustic neuroma, four had a preoperative balance disorder that resolved postoperatively. One patient died of unrelated causes. Of the remaining seven patients with caloric testings, one maintained normal caloric responses. A persistent postoperative phase shift was noted in 4 of the 7 cases with rotatory testing. Three patients were treated for a meningioma. All had a preoperative balance disorder that resolved postoperatively. Two patients showed vestibular response indicative of residual but compromised function on the involved side. The third patient showed absent responses indicating an anatomically intact nerve that does not necessarily predict functional activity. Preservation of the vestibular nerve was associated with preservation of preoperative hearing in five of the patients. This included four of the eight acoustic patients and one of the three meningioma patients. CONCLUSIONS: Preservation of the vestibular nerve did not result in a chronic balance disorder in this patient population. This study does not allow the authors to conclude if vestibular nerve preservation improves overall hearing after CPA surgery; however, these data suggest that preservation of the inferior vestibular nerve may result in less damage to the cochlear nerve in some patients. Accordingly, preservation of the vestibular nerve in CPA meningioma surgery can be recommended.