Cochlear implantation and far-advanced otosclerosis

OBJECTIVE

To evaluate results of cochlear implantation in patients with far-advanced otosclerosis.

METHODS

Sixteen patients with far-advanced otosclerosis had undergone unilateral (n = 13) or bilateral (n = 3) cochlear implantation. Surgical difficulties, incidence of complications and postoperative benefit were analyzed.

RESULTS

A full electrode insertion was achieved in all patients without surgical difficulties. All patients demonstrated excellent benefit of cochlear implantation. Binaural implantation still improves speech performances, compared to unilateral implantation. In case of residual cochlear function of one nonoperated side, a stapes surgery, performed during the same surgical time as cochlear implantation, can improve speech scores and restore bilateral hearing. Facial nerve stimulation occurred only in 1 patient.

CONCLUSION

Cochlear implantation is the method of choice for rehabilitation of patients with otosclerosis, presenting profound or total hearing loss. Patients obtain excellent benefit with a low rate of complications.

Vestibular-Evoked Myogenic Potentials in Patients With Otosclerosis Using Air- and Bone-Conducted Tone-Burst Stimulation

OBJECTIVE

Otosclerosis is a progressive disease with a remodeling process causing ossicular malformation and conductive hearing loss. The aim of this study was to investigate whether vestibular-evoked myogenic potential (VEMP) correlates with the progression of otosclerosis.

DESIGN

Fifteen patients with otosclerosis (21 ears) without operation and 10 healthy subjects (20 ears) underwent VEMP test using air-conducted (AC) and bone-conducted (BC) tone-burst stimulation.

SETTING

Tertiary referral university hospital.

RESULTS

In 21 unoperated otosclerotic ears, 5 ears (24%) showed present AC-VEMPs, and 16 ears had absent AC-VEMPs. Conversely, 16 ears (76%) displayed present BC-VEMPs and 5 ears with absent BC-VEMPs. In those with both AC- and BC-VEMPs, none of them showed air-bone gap greater than 30 dB; in those with absent AC-VEMPs but present BC-VEMPs, 27% of the ears had air-bone gap greater than 30 dB; and in those with absence of both AC- and BC-VEMPs, 80% of the ears revealed air-bone gap greater than 30 dB. Thus, a significant relationship existed among the presence of AC-VEMPs, BC-VEMPs, and magnitude of conductive hearing loss.

CONCLUSION

The presence of an AC-VEMP may indicate an earlier stage of otosclerosis, although absent BC-VEMP infers a later stage. Restated, AC-VEMPs may complement the results obtained with BC-VEMPs to classify the stage of otosclerosis.

Surgical Findings and Long-Term Hearing Results in 3,050 Stapedotomies for Primary Otosclerosis

OBJECTIVE

To evaluate with a new otologic database the results of primary stapes surgery for otosclerosis with up to 14 years of follow-up in a consecutive series of 2,525 patients operated on by the same surgeon with the same technique (stapedotomy and vein graft interposition) and to provide online access to the complete data of this study for the reviewers. To study the effect of specific operative findings (obliterative otosclerosis and simultaneous malleus ankylosis) and age at the time of surgery on the long-term outcome.

STUDY DESIGN

Prospective clinical study using a new computerized otologic database.

SETTING

: Tertiary referral center.

PATIENTS

Two thousand five hundred twenty-five patients who underwent 3,050 stapedotomies for otosclerotic stapes fixation were enrolled in this study from January 1991 to December 2004. Separate analyses were made for two unique pathologies (92 cases of obliterative otosclerosis and 19 cases of simultaneous malleus ankylosis) diagnosed during surgery and for patients in two age brackets (<or=18 yr [28 patients] and >or=65 yr [302 patients]).

INTERVENTION

Stapedotomy with vein graft interposition and reconstruction with either a Teflon piston, a bucket handle prosthesis, or a total prosthesis.

MAIN OUTCOME MEASURES

Preoperative and postoperative audiometric evaluation using conventional audiometry. Air-bone gap (ABG), bone-conduction thresholds, and air-conduction thresholds were all assessed. Postoperative audiometry was performed at 3, 6, 9, 12, 18, and 24 months and then annually for 14 years.

RESULTS

Overall, the postoperative ABG was closed to 10 dB in 94.2% of cases. The mean four-frequency postoperative ABG was 1.7 dB compared with 25.6 dB preoperatively. The mean four-frequency bone-conduction thresholds were unchanged postoperatively. A significant postoperative sensorineural hearing loss (SNHL; >15 dB) was seen in 0.5% of cases in this series. Postoperative ABG was achieved to within 10 dB in 95% of cases of obliterative otosclerosis and in 64.7% of cases of simultaneous malleus ankylosis. A significant postoperative SNHL (>15 dB) was seen in 4.8% of cases of obliterative otosclerosis and was not observed in any cases of simultaneous malleus ankylosis. Postoperative ABG was achieved to within 10 dB in 93.5% of cases in the pediatric series and in 94.5% of cases in the senior series. A significant postoperative SNHL (>15 dB) was seen in 0.7% of cases in the senior group but was not observed in the children.

CONCLUSION

Using a new otologic database, our series confirms that stapedotomy with vein graft interposition for otosclerotic stapes fixation is a safe and successful treatment for long-term hearing improvement. The deterioration in hearing with time after stapedotomy did not exceed the rate of hearing loss because of presbyacusis. Therefore, argon laser stapedotomy with vein graft interposition is our preferred surgical technique in the treatment of otosclerosis. Obliterative otosclerosis and simultaneous malleus ankylosis may be encountered during stapedotomy. Our study shows that reasonable success rates can still be expected in these situations. Stapedotomy results in the elderly and in children are comparable to those obtained in patients of other groups of age undergoing surgery for otosclerosis without an increased risk for complications.

[The deaf child: anatomy, etiologies and management]

Temporal bone imaging in children shows radioanatomical aspects and diseases distinct from the imaging and pathology results found in adults. Imaging modalities such as CT and MR bring out these differences. The aim of this study is to present the CT and MR particularities of the temporal bone during postnatal growth. The mastoid air cells form mostly in the postnatal period and the course of pneumatization is directly correlated with middle ear successive inflammatory episodes. The most frequent etiologies of hearing loss in children are reviewed, emphasizing their specificities in clinical presentation, radiological aspects, and treatment. In children, conductive hearing loss with normal tympanic membrane is mostly caused by minor aplasia rather than otosclerosis. Sensorineural hearing loss, even when unilateral, is predominantly due to malformation or infection and in rare cases to posterior fossa tumor.

Imagerie de l’otospongiose : confrontation clinique et imagerie

Otosclerosis is a primitive osteodystrophia of the labyrinthine bone. Its diagnosis must be confirmed by a CT scan in order to eliminate the other causes that may lead to conductive hearing loss with an absence of stapedial reflex: fixation of the head of the malleus to the lateral wall of the tympanic cavity, absence of the long process of the incus or stapes, gusher syndrome, primary cholesteatoma, or tympanic facial nerve neuroma blocking the stapes. Particular problems in otosclerosis must be clarified: an extension to the round window (poor postoperative results), and extension to the tympanic cavity blocking the malleus and/or the incus, the labyrinthine lumen, or the internal auditory meatus (very rare). The position of the tympanic facial nerve canal and associated abnormalities must be assessed: stapedial artery, malformations of the ossicles and/or the labyrinth, and chronic otitis media. MRI is indicated in extension to the labyrinthine lumen, the internal auditory meatus, and in postoperative complications with labyrinthitis. MRI can also evaluate the active otosclerotic focus (gadolinium enhancement).

Predictive role of Carhart's notch in pre-operative assessment for middle-ear surgery

OBJECTIVES

To evaluate the predictive role of the audiometric Carhart's notch for the assessment of middle-ear pathology prior to surgical intervention.

METHOD

In this retrospective analysis, a total of 315 operated ears of 305 patients were evaluated regarding their pre-operative pure tone audiograms and peri-operative findings. The probable relationship between the middle-ear pathologies found and the Carhart's notch found on pre-operative pure tone audiometry was investigated. Patients with conductive hearing loss who obtained at least a 10 dB improvement (at 1 and 2 kHz frequencies) in their bone conduction threshold post-operatively were included in the Carhart's notch group. The pathologies underlying Carhart's notch were compared.

RESULTS

Three hundred and fifteen ears of 305 consecutive patients with conductive hearing loss were operated on due to middle-ear pathology. In patients with otosclerosis and tympanosclerosis, a Carhart's notch was seen at 2 kHz in 28 (93 per cent) patients but at 1 kHz in only two (7 per cent). However, in patients with chronic otitis media, a Carhart's notch was seen at 1 kHz in 10 (55 per cent) patients and at 2 kHz in eight (45 per cent) patients.

CONCLUSIONS

Otitis media with effusion, tympanosclerosis and congenital malformations should be considered in the differential diagnosis of a patient with a Carhart's notch seen on pure tone audiometry. A Carhart's notch at 2 kHz indicates stapes footplate fixation, whereas one at 1 kHz indicates a mobile stapes footplate; the footplate mobility can thus be predicted pre-operatively.

Audiometric Analyses Confirm a Cochlear Component, Disproportional to Age, in Stapedial Otosclerosis

OBJECTIVE

To report the preoperative audiometric profile of surgically confirmed otosclerosis.

STUDY DESIGN

Retrospective, multicenter study.

SETTING

Four tertiary referral centers.

PATIENTS

One thousand sixty-four surgically confirmed patients with otosclerosis.

INTERVENTIONS

Therapeutic ear surgery for hearing improvement.

MAIN OUTCOME MEASURES

Preoperative audiometric air conduction (AC) and bone conduction (BC) hearing thresholds were obtained retrospectively for 1064 patients with otosclerosis. A cross-sectional multiple linear regression analysis was performed on audiometric data of affected ears. Influences of age and sex were analyzed and age-related typical audiograms were created. Bone conduction thresholds were corrected for Carhart effect and presbyacusis; in addition, we tested to see if separate cochlear otosclerosis component existed. Corrected thresholds were than analyzed separately for progression of cochlear otosclerosis.

RESULTS

The study population consisted of 35% men and 65% women (mean age, 44 yr). The mean pure-tone average at 0.5, 1, and 2 kHz was 57 dB hearing level. Multiple linear regression analysis showed significant progression for all measured AC and BC thresholds. The average annual threshold deterioration for AC was 0.45 dB/yr and the annual threshold deterioration for BC was 0.37 dB/yr. The average annual gap expansion was 0.08 dB/year. The corrected BC thresholds for Carhart effect and presbyacusis remained significantly different from zero, but only showed progression at 2 kHz.

CONCLUSION

The preoperative audiological profile of otosclerosis is described. There is a significant sensorineural component in patients with otosclerosis planned for stapedotomy, which is worse than age-related hearing loss by itself. Deterioration rates of AC and BC thresholds have been reported, which can be helpful in clinical practice and might also guide the characterization of allegedly different phenotypes for familial and sporadic otosclerosis.

An apparatus for diagnosis of ossicular chain mobility in humans

Confirmation of the conditions of the ossicles is essential for tympanoplasty. However, at present, ossicular mobility is experimentally estimated with palpation by a surgeon, and the results depend on the surgeon's skill. In this study, a new apparatus for quantitatively measuring ossicular mobility was developed. With this apparatus, the ossicles were displaced and the reaction force from the ossicles, (i.e. the load applied to the ossicles) was simultaneously detected. Ossicular mobility of three patients with otosclerosis or chronic otitis media was measured to evaluate the usability of the apparatus. The apparatus can distinguish the differences in ossicular mobility between normal and fixed ossicles, and it makes estimating the change of mobility between pre- and posttreatments for ossicular fixation possible. Positive correlation was seen between ossicular mobility and hearing level.

The learning curve in stapes surgery and its implication to training

OBJECTIVE

To identify the stapedotomy learning curve of two U.K. otolaryngologists.

STUDY DESIGN

A retrospective review of the outcome of first 100 stapedotomy operations by each surgeon. Included in the study was a postal survey of the incidence of stapes surgery by U.K. otolaryngologists.

SETTING

Two tertiary referral centers.

PATIENTS

All ears in which primary stapedotomy was performed for otosclerosis. Nonotosclerotic cases and malleus stapedotomy cases were excluded.

INTERVENTION

One surgeon used the technique of small fenestra stapedotomy with either a Teflon-wire or titanium piston but without vein graft interposition, whereas the second used the technique of stapedotomy with vein graft interposition and a Teflon piston.

MAIN OUTCOME MEASURES

A moving average with a window of 15 dB was used to plot learning curves for the postoperative air-bone gaps. Using a postoperative air-bone gap of 20 dB or better as a definition of 'success,' the success rates with the increase in surgical experience of both surgeons were plotted on graphs, the learning curves. The end point of the learning curve was defined as the point where the curve reached its peak, and the results were sustainable.

RESULTS

There was no clear-cut end point in both learning curves, although it appears that there is a landmark point at 60 to 80 cases for both surgeons. Both surgeons also had one "dead ear" in their first 15 cases. The postal survey showed that some trainers only performed small numbers of stapes surgery, whereas some otolaryngologists who performed stapedotomies regularly were not trainers.

CONCLUSIONS

The study supports a learning curve in stapes surgery. To maximize the training opportunity of trainee surgeons, it may be advisable for learning centers to form network to provide target training for the trainee who has demonstrated the necessary dexterity and temperament of an otologist.

Antimeasles Immunoglobulin G for Serologic Diagnosis of Otosclerotic Hearing Loss

HYPOTHESIS

Persistent measles virus infection of the otic capsule is suggested to be an etiologic factor in otosclerosis. Otosclerosis is a disease of complex unknown etiology causing progressive conductive and/or sensorineural hearing loss (HL).

BACKGROUND

Diagnostic methods of otosclerosis are sensitive to ossicular chain fixation with low specificity for otosclerotic stapes ankylosis.

METHODS

Nucleic acid was extracted from stapes foot plates of clinically stapes fixation patients (N = 213). Measles virus nucleoprotein RNA was amplified by reverse-transcriptase polymerase chain reaction. Amplification results were correlated to histologic findings in 49 cases. Antimeasles IgG levels of all clinically stapes fixation as well as control sera specimens were measured by enzyme-linked immunosorbent assay.

RESULTS

Among clinically stapes fixation patients, 141 stapes foot plates contained measles virus RNA. Among 49 histologic specimens, viral RNA was detectable only in histologically otosclerotic stapes foot plates (n = 35). Histology for virus-negative foot plates (n = 14) excluded otosclerosis. Antimeasles IgG levels were significantly lower in the sera of patients with virus-positive stapes than in control sera.

CONCLUSIONS

Combination of decreased antimeasles IgG serum level and conductive HL has a great specificity and sensitivity as a diagnostic method in the preoperative evaluation of ossicular chain fixations otosclerosis. Low antimeasles IgG level indicates otosclerosis, whereas high level suggests non-otosclerotic ossicular chain fixations. Preoperative elucidation of the cause of a conductive HL may suggest optional medical treatment in preference to surgical methods.

Selected complex auditory disorders

This article provides an overview of four auditory disorders relevant generally to adults and especially to veterans. The disorders are noise-induced hearing loss, idiopathic sudden sensorineural hearing loss, otosclerosis, and Méniàre's disease. Sensorineural hearing loss characterizes each, but additional aspects vary with each of the four conditions. This article describes the conditions, discusses their diagnoses and treatments, and outlines current and suggested rehabilitation. The emphasis is on recent advances, some of which await confirmation prior to possible acceptance as standard practice.

Cochlear Implantation of Patients with Far-Advanced Otosclerosis

OBJECTIVE

This current single-subject, repeated-measures study was to describe our experience with 30 patients who had been diagnosed with "far-advanced otosclerosis" and who were included in our program of cochlear implants. We analyzed the history of the patients and their families before implantation, the surgical findings, and the performance over a follow up of 3 years.

MATERIAL AND METHODS

All patients met one or more of the after criteria: 1) previous surgical intervention as a treatment of their otosclerosis; 2) signs of pericochlear hypodensities in high resolution computed tomography (HRCT) scans; and 3) family precedents of otosclerosis. All underwent standard surgical cochlear implantation.

RESULTS

In 78% of the cases, a stapedectomy had previously been realized. Cochlear otosclerosis could be appreciated in HRCT in 78% of the patients. A family history of otosclerosis was found in 40%, and 33.3% of patients had familial precedents of nonfilial hypoacusis. The mean results in the two-syllable test were 20% preimplantation, 54% 6 months after implantation, and 52%, 62%, 54% at 1, 2, and 3 years after implantation. In the CID sentence test, they were in the order of 32% preimplantation and of 64% at 6 months, 66% after 1 year, of 68% after 2 years, and reaching 72% after 3 years. No complications related to the surgery were detected.

CONCLUSION

Patients diagnosed with far-advanced otosclerosis have a good prognosis with cochlear implantation comparable to that of other patients in whom postlingual implants are performed.

Does pregnancy affect otosclerosis?

OBJECTIVE

To evaluate the effect of pregnancy on the hearing of women with otosclerosis.

STUDY DESIGN

A retrospective study of women who had undergone stapedectomy. The women were equally divided into two groups: one group with children and a control group without children. Air and bone conduction, as well as discrimination, were measured before and after stapedectomy in both groups.

PATIENTS

Ninety-four women (47 with children and 47 without) were evaluated. Because many of the women had bilateral otosclerosis, the total number of ears studied was 128.

RESULTS

Mean pure tone air and bone conduction thresholds were not worse in women with children versus those women without children. In fact, mean pre- and postoperative pure tone air and bone conduction thresholds from 500 Hz through 4,000 Hz in women with children were slightly but significantly better than women without children. There was no difference in discrimination scores between groups. Within the group with children, no significant correlation was found between number of children and hearing loss. Also, no correlation was found between breastfeeding and the amount of hearing loss.

CONCLUSION

We found no adverse effect on hearing in otosclerotic women who had children compared with women without children. Even with increasing numbers of pregnancies, no deleterious impact was noted. Air conduction, bone conduction, and discrimination were not worse in women with children versus childless women. No significant correlation was found between the number of children and hearing loss, and neither did breastfeeding affect the amount of hearing loss.

Posterior semicircular canal dehiscence: value of VEMP and multidetector CT

OBJECTIVE

To illustrate that posterior semicircular canal dehiscence can present similarly to superior semicircular canal dehiscence.

CASE STUDY

The symptomatology initially presented as probable Menière's disease evolving into a mixed conductive hearing loss with a Carhart notch-type perceptive component suggestive of otosclerosis-type stapes fixation. A small hole stapedotomy resulted in a dead ear and a horizontal semicircular canal hypofunction. Recurrent incapacitating vertigo attacks developed. Vestibular evoked myogenic potential (VEMP) testing demonstrated intact vestibulocollic reflexes. Additional evaluation with high resolution multidetector computed tomography (MDCT) of the temporal bone showed a dehiscence of the left posterior semicircular canal.

CONCLUSIONS

Besides superior semicircular canal dehiscence, posterior semicircular canal dehiscence has to be included in the differential diagnosis of atypical Menière's disease and/or low tone conductive hearing loss. The value of performing MDCT before otosclerosis-type surgery is stressed. VEMP might contribute to establishing the differential diagnosis.

Bone-Conduction Hearing and the Occlusion Effect in Otosclerosis and Normal Controls

OBJECTIVE

The goal of this study was to better understand bone-conduction hearing in subjects with normal hearing and in those with otosclerosis through the occlusion effect. With this study, the authors hope to lend credence to commonly accepted theories of bone-conduction hearing and the effect of lateralization during the Weber tuning fork test.

BACKGROUND

There are three accepted theories defining bone-conduction hearing: compressional bone conduction describes an auditory percept produced by the compression and expansion of the cochlea leading to basilar membrane vibration; inertial bone conduction describes the inertia of the ossicular chain as a result of skull vibration during bone conduction testing; whereas skull vibration may also be transmitted to the external auditory canal, surrounding soft tissues, and para-auditory structures to illicit tympanic membrane vibration known as osseotympanic bone conduction.

METHODS

Twenty normal volunteers and 17 unilateral otosclerosis patients underwent external canal sound pressure level measurement during bone-conduction testing using a standardized bone oscillator placement and stimulation paradigm. Sound was detected with a probe microphone placed in the external auditory canal in nonoccluded and occluded conditions after a 50-dB hearing level bone-conduction stimulus.

RESULTS

There was no significant difference in sound pressure level between otosclerosis and normal subjects when the external auditory canals were nonoccluded. With occlusion, sound pressure level increased in both groups, but at a statistically significantly higher level for the otosclerosis group.

CONCLUSION

Sound measured in the external canal likely represents energy lost to the environment transmitted through the middle and external ear systems, aided by the effect of both inertial and osseotympanic bone conduction. Occluding the ear leads to sound trapping and amplification. Also, the pressure exerted against the tympanic membrane reduces middle ear compliance and increases the impedance mismatch between air and the middle ear system, reflecting sound back into the external canal. This effect is further enhanced by stapes fixation to explain our data in both groups of subjects. The final common pathway in "lateralization" is probably a product of higher than normal impedance mismatch at the oval window.

Fixation of the Stapes Footplate in Children: A Clinical and Temporal Bone Histopathologic Study

OBJECTIVE

To clarify the anatomic characteristics, cause, and surgical outcomes relating to fixation of the stapes footplate in children.

STUDY DESIGN

Retrospective case review and four-center histopathologic study of temporal bones.

SETTING

Tertiary referral center.

PATIENTS

We reviewed charts and histologic specimens from 12 children, aged 7 to 13 years, who underwent surgery for footplate fixation. We also studied stapes footplates in 288 temporal bones from 181 children ranging from newborn (20-44 weeks of gestation) to 13 years of age.

MAIN OUTCOME MEASURE

Anomalies of the stapes footplate in children.

RESULTS

The average age of diagnosis of hearing loss was 6.6 years. Criteria for a diagnosis of otosclerosis were progression of a conductive hearing loss and an intraoperative finding of fixation of the anterior stapediovestibular joint in five patients. In contrast, a nonhomogeneous, thickened, fixed footplate and the absence of an annular ligament were indicators of congenital fixation in six children. In one child, there was neither new bone from the otic capsule nor any obvious otosclerotic foci. In the temporal bone study, 17 of 181 (9.4%) children had anomalies of the stapes footplates, with ankylosis in 4 (2.2%). In two subjects (1.1%), there was an otosclerotic focus not in contact with the stapes footplate.

CONCLUSION

Children younger than 6 years with various congenital anomalies are more likely to have congenital footplate fixation, which will present intraoperatively as a thickened footplate with a partial or absent annular ligament. Children older than 6 years with progressive conductive hearing loss are more likely to have otosclerosis, which presents as fixation of the anterior stapediovestibular joint. The difference in surgical outcomes is probably related to different degrees of footplate abnormality.

Effectiveness assessment of otosclerosis surgery

CONCLUSIONS

The epidemiological characteristics of otosclerosis and its treatment in Andalusia resemble those of other populations with similar socioeconomic levels. Two complementary approaches, such as questionnaires and pure-tone audiometry, are required to assess the effectiveness of otosclerosis surgery (OS) reliably and precisely.

OBJECTIVES

We describe a new method to assess effectiveness in OS. It is based on the results of pure-tone audiometry and a specially designed quality of hearing questionnaire (QHQ). The objectives of the study are: (i) to report the general epidemiologic profile of otosclerosis in Andalusia; (ii) to study the effectiveness of OS in our community using conventional methods; and (iii) to study the outcomes of OS using the QHQ and to compare them to those obtained using conventional methods.

MATERIAL AND METHODS

All 31 hospitals in the public healthcare system of Andalusia were studied. They were graded into four groups using a specially designed grouping system. The data were obtained from the minimum basic dataset. The prevalence of otosclerosis in Andalusia was calculated from the incidence data, the duration of the disease and life expectancy. To assess the effectiveness of OS, 475 clinical records from 15 hospitals representing all 4 groups were analysed. Effectiveness was assessed by conventional methods, using data obtained from pure-tone audiometry, and by using version 1.02 p of the QHQ.

RESULTS

The incidence of clinical otosclerosis was 5.67 patients/100,000 inhabitants/year. The calculated prevalence was 0.287%. The number of cases increased progressively during the study period (p<0.001). The 15-45-year age group was the largest (62.2%) and 68.4% of patients were females. The most frequent type of otosclerosis was estapediovestibularis (fenestral), non-obliterative (91.8%). Only 48 cases (2.3%) of cochlear and 45 (2.2%) of obliterative otosclerosis were reported. The most frequently employed therapeutic procedures were stapedectomy and stapedotomy (75.70%). The average total and preoperative lengths of stay were 3.59 and 1.04 days, respectively. There were significant differences between the different types of otosclerosis. Improvement in the air-bone gap was 15.37+/-1.19 dB (n=164) and the overclosure or operative damage was 0.49+/-0.85 dB (n=164). A gap improvement of 10-40 dB was observed in 61.4% of patients. The > 65 years age group showed the best gap improvement but the largest variability. The quality of hearing measured by the QHQ showed that, in general, a better gap improvement was associated with a higher quality of hearing (Pearson correlation r=0.183; p<0.05). The 15-45-year age group had the worst gap improvement but, in contrast, the better quality of hearing.

Shape-Memory Stapes Prosthesis for Otosclerosis Surgery

OBJECTIVES

The aim of this study was to determine the efficacy of a shape-memory alloy, Nitinol, as a component of an improved stapes prosthesis.

STUDY DESIGN

Prospective laboratory and clinical study to develop a Nitinol stapes prosthesis.

METHODS

Various diameters of Nitinol wire and temperature transition variants were analyzed with regard to ease of deformation, response to heating, and strength. The size and geometry of the closed hook was determined by measurement of 50 incus cadaver bones. Several heat sources for activating the shape memory were evaluated, including electrocautery, lasers, and warm water. Trial surgeries were then performed on human temporal bones in the laboratory. The closure characteristics of the Nitinol loop were studied. Magnetic resonance imaging (MRI) testing at 1.5 Tesla was performed to determine safety during MRI studies. Preliminary human subject trials were then instituted.

RESULTS

In all cases, a low heat condition was ample to activate the shape memory characteristics of the hook and return it to a closed position after it had been opened. Laser power was generally set well below the power needed for removing bone. The Nitinol loop closed snugly around the incus with application to the top of the hook with a low temperature laser setting. Almost any heat source was effective. MRI testing at 1.5 Tesla showed no movement of the prosthesis. Preliminary results in human subjects showed excellent air-bone closure. The Nitinol loop holds uniform contact around the incus.

CONCLUSIONS

The Nitinol piston greatly simplifies the stapedectomy procedure by taking the need for a hand operated instrument out of the surgeon's hands. Because of the nature of the Nitinol wire, it can never over-crimp. All these characteristics make the prosthesis advantageous for otosclerosis surgery.

The effect of stapedotomy on tinnitus in patients with otospongiosis

Stapedotomy is primarily performed to treat hearing loss secondary to otospongiosis, although some patients find that the accompanying tinnitus is more bothersome than the hearing loss. We prospectively studied 23 consecutive patients with tinnitus secondary to otospongiosis who had undergone stapedotomy, and we compared their pre- and postoperative medical and audiologic findings. Patients' annoyance with their tinnitus was quantified by means of a visual analog scale, and their air-conduction thresholds were determined by measurements of a 4-frequency pure-tone average (0.5, 1, 2, and 4 kHz). Statistical analysis was performed using the paired Student's t test and Fisher's exact test. In the group as a whole, the mean tinnitus annoyance visual analog scores were 8.34 preoperatively and 1.56 postoperatively, a highly significant difference. Clinically, 22 of the 23 patients (95.7%) achieved satisfactory control of their tinnitus (improvement or complete resolution) following stapedotomy. With respect to hearing loss, all patients clinically improved postoperatively, and audiometry confirmed improvement at all 4 frequencies between 0.5 and 4 kHz. An air-bone gap of less than 10 dB was noted in 17 patients (73.9%). We conclude that in addition to improving hearing, stapedotomy also provides good control of tinnitus.

[Is imaging possible for otosclerosis? Characteristics of the disease and a survey of the clinical relevance of imaging]

Otosclerosis is a localized progressive disease of bone remodeling within the otic capsule of the human temporal bone. Histomorphologically, active cochlea otosclerosis (otospongiosis) is diagnosed in the presence of foci of demineralization in the otic capsule. The clinical symptoms of otosclerosis are associated with mixed and sensorineural hearing loss. With recent technological advances, diagnostic imaging of the inner ear is becoming more and more important in the evaluation of diseases affecting the cochlea. Studies could demonstrate that otosclerosis has a characteristic appearance on high-resolution computed tomography (HRCT), producing a distinctive pericochlear hypodense double ring. Its appearance on MRI is not as readily appreciated, producing a ring of intermediate signals in the pericochlear and perilabyrinthine regions on T1-weighted images, demonstrating mild to moderate enhancement after gadolinium administration. The ethiology and pathophysiology of otosclerosis are described and a review of the literature is given to illustrate the clinical relevance of imaging in otosclerosis.