The American journal of otology最新文献

Objective: To investigate a narrow internal auditory canal (IAC) syndrome using functional magnetic resonance imaging (fMRI) of the auditory cortex.

Study design: The study design was a case report. The follow-up period lasted 18 months.

Setting: The study was carried out in the audiology clinic of an ear, nose, and throat department and in the department of pediatric neuroradiology at a university hospital.

Main outcome measures: Age-appropriate observational audiometry, objective audiovestibular tests, computed tomography (CT), magnetic resonance imaging (MRI), and (fMRI) of the auditory cortex were performed to analyze in detail the profound deafness of a young child.

Results: Audiovestibular examination demonstrated both measurable hearing and normal vestibulo-ocular reflex, and CT showed narrow IACs combined with normal labyrinths. Axial MR images completed by sagittal sections perpendicular to the IAC delineated a single nerve that was initially supposed to be the facial nerve. No cochleovestibular nerve was identified. However, fMRI performed with the patient under general anesthesia demonstrated activation of the primary auditory cortex during 1-kHz monaural stimulation on the left side.

Conclusions: The absence of cochleovestibular nerve on MR studies cannot exclude connections between the inner ear and the central auditory pathways. This might be caused by a lack of spatial resolution of anatomical MR studies. The single nerve delineated within the IAC might also carry both facial and cochleovestibular fibers. Functional MRI can assess the cortical response to acoustic stimuli when aplasia of the cochleovestibular nerve is suspected. This case study illustrates a novel and atypical presentation of cochlear nerve dysplasia.

Purpose: To study and understand the contribution made by Adam Politzer (1835-1920) to 20th century otology and analyze his place in the history of otology.

Method: A study of his four reference works, some of his hundreds of publications in medical journals, and diverse publications written about him.

Results: All areas of otology have been studied, compiled, and improved through his assorted publications, notably his atlas of otoscopy published in 1865, the first work of its kind, expanded and reedited in 1896; his 10 tables of the anatomy of the ear amended in 1873; his textbook of the diseases of the ear, which was first published in two volumes in 1878 and 1882 and subsequently reedited four times as one volume, the last time being in 1908; his anatomy and histology book published in 1889; and his book on the history of otology, which up to now is the most complete tome existing on the subject, edited in two volumes in 1907 and 1913. No other has been as prolific as he. He invented, in particular, a revolutionary method of making the eustachian tube permeable--a method that made him famous and carries his name. He also developed an acoumeter to measure hearing and was the first to describe certain pathologic conditions histologically, of which otosclerosis is one.

Conclusion: Politzer is certainly the greatest otologist of the 19th century and probably one of the greatest of all time. His influence on the 50 years of otology has never been equaled. He deserves a double mention in the history of otology: as an otologist and as a historian. It is in his honor that the International Society of Otology bears his name.

Objective: To determine whether the nerves of origin of vestibular schwannomas can be predicted using vestibular evoked myogenic potentials (VEMPs).

Study design: The study was a retrospective analysis.

Setting: The ear, nose, and throat department of Tokyo Medical and Dental University.

Patients: Twenty-eight patients undergoing removal of vestibular schwannomas were included in the study.

Interventions: Patients underwent pure tone audiometry, VEMP testing, caloric testing, and magnetic resonance imaging preoperatively. Hearing level, caloric weakness, maximum tumor size, and the nerves of origin of tumors were compared with VEMP testing.

Main outcome measure: Results of VEMP testing.

Results: Comparisons between VEMPs and results of the other three examinations revealed no correlations. Complete disappearance of VEMPs was observed only in patients with tumors arising from inferior vestibular nerves. Patients in whom hearing was preserved tended to have preserved VEMPs. Some patients showed damaged hearing and normal VEMP results, although with inferior vestibular schwannomas. A patient with a tumor arising from a cochlear nerve exhibited preservation of VEMP, preserved caloric response, and moderate hearing loss.

Conclusions: Inferior vestibular nerve function and hearing level were reflected in VEMP results. Prediction of the nerve of origin of a tumor was possible only in certain restricted cases.

Hypothesis: Experimental endolymphatic hydrops leads to an endolymph-perilymph pressure imbalance that is responsible for the loss of auditory sensitivity in the ear.

Background: This study investigates whether intralabyrinthine pressure is a factor in the auditory dysfunction of experimental endolymphatic hydrops.

Methods: Auditory function was investigated in 10 guinea pigs 90 to 120 days after endolymphatic sac ablation by measuring compound action potentials in response to acoustic stimuli including alternating clicks and tone bursts of 0.5, 1, 2, 4, and 8 kHz. After auditory thresholds to the various stimuli were established, endolymphatic and perilymphatic pressures were measured with a no-flow micropressure measuring system. The cause of the hearing loss in Meniere's disease, especially in the early phases of this condition, remains an enigma. Histologic temporal bone preparations show a disproportion in the volume of endolymph to perilymph with an expanded and distorted membranous labyrinth. Speculation as to whether an endolymph-perilymph fluid pressure imbalance is responsible for these morphologic changes were raised by Hallpike and Cairns (1) in their initial report of the histopathology of Meniere's disease. Further speculation has questioned whether this pressure imbalance may be responsible for the symptoms and physical finding of this condition, including hearing loss. The ability to produce experimental endolymphatic hydrops in the guinea pig secondary to surgical occlusion of the endolymphatic sac and duct has been useful in studying various aspects of Meniere's disease (2). Investigators have been able to demonstrate auditory threshold shifts with hydrops. Elevated endolymph-perilymph pressure gradients have also been demonstrated (3). This

Results: Increased auditory thresholds were noted in the hydrops ears at all tested parameters (p < 0.03). A relative increase in endolymph over perilymph pressure was found in hydrops ears as previously reported. The increase in endolymph-perilymph pressure of hydrops could not be correlated directly to the elevated auditory threshold shift.

Conclusion: Endolymphatic hydrops is a complex pathologic state with multiple inner ear alterations including abnormal intralabyrinthine pressure. Factors other than or in addition to pressure contribute to the auditory threshold shift of hydrops.

Objective: The aim of this study was to analyze the natural course of unilateral acoustic neuromas and to evaluate the advantages and disadvantages of an initial conservative approach.

Methods: Between 1989 and 1994, 74 consecutive patients with the diagnosis of unilateral acoustic neuroma were evaluated at the Department of Otorhinolaryngology, University of Zurich. Their charts and magnetic resonance imaging scans were retrospectively analyzed regarding duration and type of symptoms, initial tumor size, tumor growth pattern, and audiometric data.

Results: Of the 74 tumors, 68.9% (51/74) did not grow during a mean follow-up of 35 months. Eight (16%) of these tumors had radiologically documented tumor regression. Twenty-three tumors did grow, 16 of them (70%) with a growth rate of <2 mm/year. There was a statistically significant correlation between the first-year and the total growth rate, indicating that the tumor's behavior in the first year is highly predictive of its subsequent growth pattern. Patients with progressive hearing loss as a first symptom had a significantly lower tumor growth than those presenting with tinnitus, sudden hearing loss, or dizziness. Patients with tumor growth showed a greater tendency for hearing loss, although this trend was significant only for isolated frequencies. In 12% of the cases (9/74), the initial conservative approach had to be abandoned in favor of surgery.

Conclusion: Watchful expectation can be regarded as a safe approach for selected cases of acoustic neuromas. Surgery or irradiation is indicated in patients with proven growth of their tumors.

Objective: To show the clinical outcome in patients with meningioma within or at the internal auditory canal (IAC) operated on by the extended middle cranial fossa approach.

Study design: Retrospective case review.

Setting: A tertiary referral center.

Patients: Twelve patients, 9 women and 3 men, whose ages ranged from 37 to 70 years (mean 57 years). One tumor was entirely intracanalicular, 5 had an intra-extracanalicular growth, 3 were centered at the posterior porus lip, and 3 tumors were localized in the midpetrosal region with spread into the IAC.

Intervention: Extended middle cranial fossa approach.

Main outcome measures: Magnetic resonance imaging and computed tomography were used for follow-up and reevaluation of the operative sites. Facial nerve function and hearing were examined.

Results: Complete resection was achieved in 10 (83%) of 12 patients. The retrosigmoid approach was necessary to complete tumor resection in one patient, and in another, partial resection was done because of the en plaque type of tumor growth. There was one unexpected recurrence. All patients retained normal or near-normal facial nerve function postoperatively. Three patients were deaf before surgery, and preoperative hearing level was preserved in 42%.

Conclusions: Attempted hearing preservation surgery is justified in patients with small tumors and preserved hearing, because tumor exposure and safety of resection are comparable with that of hearing-destructive procedures. Lateral extension of the tumor to the fundus does not prevent complete resection with preservation of function, and elective bone resections beyond the visible tumor margins seem not to substantially influence the tumor recurrence rates.

Objective: To determine the clinical utility of high-resolution computed tomography (HRCT) for temporal bone trauma evaluation and management.

Study design: Retrospective review.

Setting: Level I trauma center.

Patients: Patients (n = 105) with evidence of temporal bone trauma.

Main outcome measures: Statistically significant associations between HRCT, clinical, audiometric, and head CT findings, and management decisions; role of HRCT in management decisions.

Results: Statistical analysis demonstrated poor association between specific clinical and HRCT findings, and between HRCT findings and management decisions. The HRCT complemented decision making in 10% of cases and revealed asymptomatic carotid canal fractures in 9% of cases.

Conclusion: Routine HRCT yields minimal clinical utility. Selective use of HRCT may complement decision making, but patient management is predominantly influenced by other factors. Although angiography was performed in cases of asymptomatic carotid canal fractures, no clinical utility for this practice was demonstrated. An algorithm for temporal bone trauma evaluation and management is presented.

Objective: To report the hearing results of the surgical treatment of tympanosclerosis.

Study design: A retrospective review of surgically treated cases of tympanosclerosis.

Setting: A tertiary referral center.

Patients: One hundred fifteen patients with middle ear tympanosclerosis operated on between 1987 and 1996, with an average age of 36 years (range 18-59 years). Cases were classified into four groups according to Wielinga and Kerr. Those with an associated cholesteatoma were excluded.

Intervention: Depending on the ossicular status, either mobilization of the major ossicles or epitympanic bypass procedure, mobilization of the stapes or stapedectomy.

Main outcome measures: The postoperative pure-tone average was compared with the preoperative levels by use of conventional audiometry. The air-bone gap was measured.

Results: The average postoperative air-bone gap was 18.0+/-10.21 dB in the type II group (attic fixation of the malleus-incus complex with a mobile stapes). 21.8+/-9.5 dB in the type III group (mobile malleus-incus complex, if present, with stapes footplate fixation), and 22.92+/-10.03 dB in the type IV group (fixation of both the stapes footplate and the malleus-incus complex). Patients with a fixed malleus and mobile stapes had significantly better hearing results than those with stapes fixation (p = 0.042, Mann-Whitney U test).

Conclusion: In ossicular attic fixation, atticotomy and mobilization of ossicles yielded better results than did the epitympanic bypass procedure. The difference, however, did not reach statistical significance. Patients with fixed stapes treated with stapedectomy displayed good hearing results immediately after surgery, but the air-bone gap deteriorated after some time.

Purpose: To correlate the absence of distortion-product otoacoustic emissions observed in sudden hearing loss (SHL) with a possible thromboembolic vascular cause, using an animal model.

Background: Distortion-product otoacoustic emissions (DPOAEs) are sensitive to cochlear disorders and are absent in cochlear injury. In a previous study, the authors showed that 75% of patients with SHL who have no measurable emissions do not recover hearing. The underlying cause of the loss of emissions is unknown, but it may be secondary to cochlear ischemia.

Methods: Six New Zealand white rabbits underwent unilateral cochlear embolization through the use of circulating iron particles under magnetic control. Cochlear function was monitored through DPOAE recordings of the experimental and control ears.

Results: In all animals, a rapid decrease in emissions was noted, which fluctuated but returned to baseline within 2 hours to 3 weeks after embolization, leaving no measurable residual defects. The DPOAEs were suppressed by 5 to 19 dB within 10 minutes of injection of iron solution and magnet placement. The lowest emissions were obtained at 30 minutes and again at 120 minutes, which were 12 to 37 dB below preembolization levels. Two animals returned to baseline DPOAE levels at 1 to 3 weeks, with no identifiable residual deficits.

Conclusion: It is likely that the loss of emissions seen in the present study is related to cochlear ischemia. The early suppression of DPOAEs in the rabbit cochlea after embolization may parallel that in SHL patients with absence of DPOAEs on presentation.

Background: Morbid obesity is increasing in the United States population. Morbidly obese patients may have disabling pulsatile tinnitus (PT) secondary to pseudotumor cerebri syndrome and often seek treatment from otolaryngologists because of this symptom.

Objective: To determine the effectiveness of weight reduction surgery (WRS) for relief of PT in patients with morbid obesity.

Study design: Retrospective study of morbidly obese patients with associated PT.

Setting: Academic tertiary referral center.

Patients: Sixteen women with morbid obesity and associated PT who underwent WRS.

Results: Median age was 34 years (range 24-45 years). Average preoperative body mass index was 45 kg/m2 (range 33-70 kg/m2). Average weight loss was 45+/-17 kg (range 25-99 kg). Average postoperative weight was 75+/-14 kg (range 57-105 kg). The average preoperative cerebrospinal fluid pressure was 344+/-103 mm H2O (range 220-520 mm H2O). Postoperative measurements of cerebrospinal fluid, obtained on 4 patients, revealed an average decrease in pressure of 198 mm H2O (range 120-400 mm H2O). Thirteen patients experienced complete resolution of their PT (81%). Three patients continued to have PT despite significant weight reduction.

Conclusions: Weight reduction surgery was effective in relieving PT in morbidly obese patients with associated pseudotumor cerebri syndrome and should be considered when conservative management has failed.