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.
OBJECTIVETo determine the prevalence and character of vestibular abnormalities and the changes in vestibular function that occur in unilateral Ménière's disease.STUDY DESIGNRetrospective case review.SETTINGAmbulatory patients at a tertiary care facility.PATIENTSEntry criteria included a diagnosis of unilateral Ménière's disease and test results from at least two vestibular test sessions at the Johns Hopkins Otologic Vestibular Laboratory. One hundred twenty-two cases were evaluated.MAIN OUTCOME MEASURESElectronystagmographic evaluation, including caloric testing; audiometric tests; and medical records.RESULTSCaloric weakness was demonstrated in 58% of patients on the involved side and in 19% on the normal side. Complete paralysis was found in 7%. Directional preponderance was seen in 33% of patients and completely normal scores in 27%. During the course of the disease, responses become weaker in 26% of patients and stronger in 11%. Of 39 patients tested more than twice, 26% showed both increases and decreases in caloric responses. After an acute attack, only one of eight patients showed a depressed response on the diseased side, and three showed an increased response. Spontaneous nystagmus, seen within 24 hours of an attack in 54 cases, was directed away from the diseased ear in only about one half of the cases. Benign paroxysmal positional vertigo was found in 44% of these patients.CONCLUSIONSPossible pathophysiologic explanations for the various test results in Ménière's disease are discussed. Interpretation of caloric test results should take into account the absolute value of the slow phase eye speed scores, in addition to the right-left difference score. Also, established standards for the normal range of fluctuation in both absolute and comparative scores should be used when more than one test session has been undertaken.
Objective: To study the relationship of the length of the external aperture of the vestibular aqueduct and the ratio of the summating potential and action potential (SP:AP) in patients with Meniere's disease.Study Design: Retrospective case study.Setting: Neurology referral center.Patients: Fifty-four patients with Meniere's disease and nine control subjects without Meniere's disease.Intervention: The external aperture of the vestibular aqueduct was measured from a three-dimensional surface reconstruction computed tomography scan. Transtympanic electrocochleography was performed on patients with Meniere's disease.Main Outcome Measure: The length of the external aperture of the vestibular aqueduct in the Meniere's disease ears was related to the SP:AP ratio in the Meniere's disease ears and compared with controls.Results: The average length of the external aperture was 3.79 +/- 2.92 mm in Meniere's disease cars and 5.35 +/- 1.73 mm in the control ears (p < 0.05), An enlarged SP:AP ratio was found in 95% of ears in the group with nonvisible external apertures of the vestibular aqueduct, 91% of ears in the <5 mm group, 58% of ears in the 5-7 mm group, and 29% of ears in the >7 mm group (chi-square = 24.814; p = 0.000).Conclusions: The length of the external aperture of the vestibular aqueduct in patients with Meniere's disease is significantly shorter than in those without Meniere's disease, Endolymphatic hydrops, evidenced by an enlarged SP:AP ratio, was related to the length of the external aperture of the vestibular aqueduct, The shorter the external aperture, the more often the SP:AP ratio was enlarged. A short or nonvisible external aperture of the vestibular aqueduct is a predisposing factor to the development of Meniere's disease.
Objective: To reevaluate the validity of the soft-wall reconstruction method of the posterior meatal wall in surgeries for cholesteatomas.Study Design: Retrospective case review.Patients: Subjects consisted of 52 patients (54 ears) with fresh cholesteatoma (excluding residual or recurrent cholesteatomas) who were operated by the soft-wall reconstruction method in our clinic and observed for more than 2 years after surgery, and 29 patients (29 ears) who were operated by canal-wall-down and open method.Main Outcome Measures: Postoperative period required for complete epithelization (dry ear), hearing, and incidence of the residual and recurrent cholesteatomas were compared with those operated by canal-wall-down and open method. The postoperative conditions of the soft posterior meatal wall was also investigated. Results: Postoperative period to be a dry ear was significantly shorter in the soft-wall reconstruction group than in the canal-wall-down and open group (Student's t-test, t = 2.99, p < 0.01). There was no significant difference in the postoperative hearing or incidence of residual and recurrent cholesteatomas between the two groups.Conclusions: These results indicate that the soft-wall reconstruction method seems more versatile than the canal-wall-down and open method for cholesteatoma surgery.
BACKGROUND Matrix metalloprotease-9 (MMP-9) plays an important role in the degradation of extracellular matrix (ECM). In cholesteatoma there are significant changes in the composition of the ECM, supporting the view of a disturbed cell-ECM interaction. It has been reported that in cholesteatoma tissues, MMP-9 is expressed in epithelial cells but not in stromal cells. In this study, we report conflicting results regarding the identity of the cholesteatoma cells that express MMP-9. METHODS An immunohistochemical assay was performed to examine the expression of MMP-9 in 25 cases (formalin-fixed paraffin-embedded sections) of cholesteatoma, using an MMP-9-specific monoclonal antibody. RESULTS In all cholesteatomas examined, MMP-9 was expressed in the stromal cells but not in the epithelial cells. MMP-9 immunostaining was undetectable in external auditory meatal skin (n = 5) and tympanic membrane (n = 3). CONCLUSIONS These results suggest that the MMP-9 expressed in stromal cells may be involved in the disturbed cell-ECM interaction associated with the process of cholesteatoma formation.
This study defines the three-dimensional location of the posterior-most point of the tympanic segment of the facial nerve (TSFN) relative to the posterior-most point of the short process of the incus, using ultrahigh-resolution computed tomography (CT) of the temporal bone.Included were patients who had been referred for CT of the temporal bone for various reasons other than suspected pathologic conditions of the middle ear. The decision whether to include a patient in the study was based on the referring physician's referral note for the examination.All of the patients underwent axial CT of the temporal bone, with consecutive slices of 1.1 mm width and 0.5-mm increments.The posterior-most point of the short process of the incus was identified on axial CT and was superimposed onto a lower axial slice in which the posterior-most point of the TSFN was identified. Its shortest distance to the TSFN was measured. Afterward, the length of the TSFN that remained posterior to the perpendicular of the posterior-most point of the short process of the incus was measured by measuring the length of TSFN that could be seen posterior to the point of bisection of the line marking the shortest distance between the posterior-most point of the short process of the incus and the FN in the previous measurement. The measurements were performed on 30 normal temporal bones.The shortest distance measured between the posterior-most point of the short process of the incus and the TSFN was, on average, 3.31 mm for all 30 ears (range 2-4.8 mm). The length of TSFN that could be seen posterior to the perpendicular of the most posterior point of the short process of the incus was, on average, 2.70 mm (range 1.80-3.90 mm).In addition to defining the spatial location of the posterior-most point of the TSFN, this study also offers a practical method by which the surgeon can evaluate, preoperatively, how far medial to the incus and how much posterior to the posterior-most point of the short process of the incus the facial nerve is located.
OBJECTIVETo report the hearing results of the surgical treatment of tympanosclerosis.STUDY DESIGNA retrospective review of surgically treated cases of tympanosclerosis.SETTINGA tertiary referral center.PATIENTSOne 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.INTERVENTIONDepending on the ossicular status, either mobilization of the major ossicles or epitympanic bypass procedure, mobilization of the stapes or stapedectomy.MAIN OUTCOME MEASURESThe postoperative pure-tone average was compared with the preoperative levels by use of conventional audiometry. The air-bone gap was measured.RESULTSThe 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).CONCLUSIONIn 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.
Objective: Although transposition of the facial nerve is crucial in infiltrative vascular lesions involving the jugular foramen, the objective was to show that a conservative approach to management of the facial nerve is sufficient with jugular foramen neuromas because of their noninfiltrative, less vascular nature and medial location in the jugular foramen.Study Design: Retrospective case review.Setting: Tertiary, private, multiphysician, otologic practice.Patients: Sixteen patients with jugular foramen schwannoma (18 procedures) treated between January 1975 and October 1995. The 8 male and 8 female patients ranged in age from 13 to 66 years (mean age 47.7 years).Intervention: One-stage, total jugular foramen neuroma removal without transposition of the facial nerve. using a variety of surgical approaches.Main Outcome Measures: Facial nerve transposition (yes or no), House-Brackmann facial nerve grade, lower cranial nerve status, complications.Results: One-stage total tumor removal was accomplished in all the cases. In 13 (72%) of the neuromas, removal was accomplished without facial nerve transposition. Transposition was performed in 2 revision cases in which scar tissue from a previous operation prevented complete control of the carotid artery and safe removal, 2 cases with large tumor extension anteriorly to the petrous apex, and 1 case with extensive involvement of the middle ear. A House-Brackmann facial nerve Grade I or II was obtained in 16 of the 18 procedures, with 1 Grade III and 1 case that remained Grade V, as it was preoperatively.Conclusions: One-stage, total tumor removal can be achieved with excellent control of the important vascular structures and without transposition of the facial nerve in a majority of jugular foramen schwannomas.
BACKGROUND:Among the cranial nerves, the facial nerve is most liable to be damaged. Pathologic changes in the facial motor nucleus (FMN) after nerve injury are not well recognized, and the optimal time for facial nerve reconstruction after axotomy is controversial. In this study, to clarify the pathologic change in the FMN after axotomy and to determine the best time for surgery, facial motoneuronal death was investigated after facial nerve injury.METHODS:Sixty Wistar rats were divided into proximal and distal groups. In the proximal group, the right facial nerve was transected at the porus of internal acoustic meatus. In the distal group, the nerve was cut at the stylomastoid foramen. The animals were sacrificed from day 3 to day 60 after surgery, and the brainstem was fixed with 4% paraformaldehyde. The FMN were then examined in serial sections stained with Cresyl Violet, and facial motoneurons were counted under a light microscope.RESULTS:The death rate of facial motoneurons in the animals that underwent proximal axotomy was found to be higher and cell death occurred earlier than in the distal axotomy animals at every time point. Moreover, neuron death increased with time and peaked at 15 days after surgery.CONCLUSIONS:The results indicate that the injury site was correlated with facial motoneuronal death, and suggest that reconstructive surgery should be performed as early as possible.
Objective: Patients with benign paroxysmal positional vertigo (BPPV) often experience postural instability as well as brief episodes of vertigo. The purpose of this study was to determine whether successful resolution of the episodic vertigo, through use of the canalith repositioning treatment, would be accompanied by improvement in postural stability.Study Design: Prospective clinical study.Setting: Outpatient tertiary care facility in a university.Patients: Thirty-three patients with a diagnosis of the canalithiasis form of BPPV affecting the posterior canal unilaterally. All patients had complete remission of the positional vertigo after treatment. Patients with abnormal caloric or rotary chair test results were excluded from the study.Intervention: The posterior canal BPPV was treated by the canalith repositioning treatment.Main Outcome Measures: Postural stability was assessed by computerized dynamic posturography before and 1 to 2 weeks after treatment. Six different subtests were used.Results: A significant number of patients had abnormal stability, as measured with computerized dynamic posturography, before treatment. After treatment there was a significant increase in the number of subjects with normal results on the different subtests; however, not all patients had normal postural stability. Younger subjects were more likely to show improved stability.Conclusions: Treatment of BPPV using the canalith repositioning treatment results in improved postural stability in patients with BPPV. Not all patients have normal stability after treatment, however, and assessment and treatment of the balance problems may be necessary.
OBJECTIVE:The aim of this study was to evaluate the efficiency of prophylactic perioperative glucocorticoid treatment during stapes surgery in preventing damage to the inner ear and reducing the frequency of early postoperative complications.STUDY DESIGN:A prospective, randomized, unblinded study design was selected.SETTING:The study was conducted at an academic tertiary referral center.PATIENTS:Ninety-five consecutive patients undergoing erbium:YAG laser-assisted stapedotomy for otosclerosis between 1996 and 1999 were included.MAIN OUTCOME MEASURES:The preoperative minus postoperative (1-4 days and at least 6 weeks) average pure-tone bone conduction thresholds at 1, 2, and 4 kHz were compared in the prednisolone and control groups by the Mann-Whitney U Test. In addition, the occurrences of sensorineural hearing loss of >10 dB, nystagmus, vertigo, and tinnitus were counted and evaluated by use of the Freeman-Halton or Fisher's exact test, respectively.RESULTS:Prophylactic perioperative prednisolone treatment was not able to improve the early postoperative average bone conduction thresholds or reduce the frequency of early sensorineural hearing loss (p > 0.5). The patients who received perioperative prednisolone treatment experienced postoperative vertigo more frequently than did the control patients (p < 0.05).CONCLUSION:Perioperative cortisone prophylaxis for prevention of inner ear damage during stapes surgery is ineffective and is associated with increased postoperative patient discomfort.
Hypothesis: The adhesive octylcyanoacrylate is not associated with significant inner ear toxicity in a guinea pig model.Background: Many cyanoacrylate adhesives have been investigated For use in otologic surgery, but variable ototoxicity has been reported. Octylcyanoacrylate is a medical-grade adhesive with many properties that make it ideal for use in the car. It is free of contaminants; it forms a strong, flexible bond, and it inhibits the growth of gram-positive organisms in culture. This is the first study to assess the ototoxicity of this new adhesive.Methods: Fourteen adult guinea pigs were used. Preoperative auditory brainstem responses (ABRs) were determined. Bilateral antrotomies were performed, and the ears were randomized to adhesive and control (saline) groups. In the adhesive ears, 0.5 or 0.1 mt of octylcyanoacrylate was instilled into the middle ear. Eight weeks later, postoperative ABRs were determined, the animals were killed, and the temporal bones were removed. Middle ear changes were noted, and the ossicular chain was assessed. Cochlear hair cell analyses were performed. Histologic assessment of the middle ear mucosa was performed.Results: There was a higher incidence of conductive hearing loss in the adhesive group secondary to fixation of the ossicular chain, but there was no significant difference in bone conduction thresholds. The median postoperative bone conduction thresholds (dB peak sound pressure level) was 15.0 in the control group and 17.5 in the adhesive group, p = 0.89. There was also no significant difference in inner hail cell counts (0.4% vs. 0.5% median hair cell loss, p = 0.72) or outer hair cell counts (3.78 vs. 3.0% median hair cell loss, p = 0.23) for the adhesive and control groups, respectively. Histopathologic analysis of the middle ear mucosa demonstrated variable mild to moderate foreign body reaction with no evidence of mucosal ulceration or necrosis.Conclusions: A large amount of octylcyanoacrylate placed in the middle ear of the guinea pig did not cause any morphologic or functional evidence of inner car toxicity. This new adhesive is a promising tool for otologic surgery.
OBJECTIVE:Hearing loss remains the most common symptom associated with acoustic neuroma. This study documents the audiometric findings from 721 acoustic neuroma procedures.STUDY DESIGN:This was a retrospective study. The preoperative audiometric data were compiled and were analyzed by patient age, gender, tumor size, time of surgery, and neurofibromatosis Type 2 (NF 2). Postoperative audiometric data were arranged and compiled in the same way. The hearing classification proposed by the AAO-HNS was applied to all preoperative and postoperative cases.SETTING:Tertiary referral center.PATIENTS:Surgically confirmed acoustic neuroma patients who had not previously received surgical or radiosurgical therapy. Patients underwent surgery by the retrosigmoid approach.INTERVENTION:Surgical removal of an acoustic neuroma. MAIN OUTCOME RESULT: Provision of pure tone and speech data from a group of acoustic neuroma patients, including application of the recently introduced and accepted AAO-HNS hearing classification system.RESULTS:Preoperative audiometric data were obtained from 694 of 721 patients (96%), of whom 619 had measurable hearing. Postoperative audiometry was performed on 606 patients; 152 had usable data. The combined preoperative audiometric data revealed a high frequency sensorineural hearing loss. Word recognition was servicable. The postoperative pure tones and word recognition scores were worse than preoperative scores. Age, gender, tumor size, and time of surgery had some impact on the preoperative hearing and the postoperative result; NF 2 did not.CONCLUSIONS:The study confirms that hearing alteration is almost universal in acoustic neuroma patients. Hearing preservation is possible in a significant number of cases; however, the postoperative auditory function tends to be worse.
Objective: Isolated congenital stapes ankylosis is rare but is a definite entity. Both small series and case reports have been published in various languages. The aim of this study was to review the world literature regarding isolated congenital stapes ankylosis and to critically evaluate the embryonic development of the stapes to explain the possible pathologic development of this ankylosis.Data Sources: All the publications in the English, German, and French literature regarding congenital stapes anomalies were reviewed, and original research articles on the embryonic development of the stapes and related structures were extensively and critically reviewed.Study Selection: Of the many varieties of congenital stapes anomalies described in the literature, only the isolated congenital stapes fixation due to footplate or suprastructure fixations were selected in this study.Data Synthesis: After extensive and critical review of the embryonic development of the stapes, the complex and confusing embryonic development is explained in a simplified way with schematic illustrations for easy understanding. The possible theories of congenital stapes ankylosis are explained on an embryologic basis and supplemented with schematic illustrations.Conclusion: Based on the development of the stapes an attempt has been made to explain the possible theories for the basis of suprastructure fixation. Theories of congenital fixation of footplate also discussed.
