Postoperative complications in otospongiosis: usefulness of MR imaging.
(1/23)
BACKGROUND AND PURPOSE: Sensorineural hearing loss (SNHL) is a rare complication of stapes surgery that may arise for many reasons. Usually, the pathogenesis of SNHL can be established by clinical and CT examinations. The purpose of this study was to evaluate the utility of MR imaging when CT findings are normal or not contributive. METHODS: Eleven patients with SNHL (in some instances, associated with vertigo) after stapedectomy, in whom CT showed no well-defined cause, were examined by MR imaging. RESULTS: MR studies established the additional findings of reparative intravestibular granuloma (n = 2), intralabyrinthine hemorrhage (n = 1), and bacterial labyrinthitis (n = 1). In five cases, MR findings were similar to CT findings. In two cases, CT and MR results were normal. Revision surgery was performed in five patients and confirmed the MR findings in each case. CONCLUSION: If CT is not contributive as to the origin of SNHL and vertigo occurring after stapes surgery, then MR imaging may be helpful in these patients. (+info)
Results after revision stapedectomy with malleus grip prosthesis.
(2/23)
Revision stapedectomy with a malleus grip prosthesis is a technically challenging otologic procedure. The prosthesis is usually longer and extends deeper into the vestibule than a conventional stapes prosthesis, creating the potential to affect the vestibular sense organs. The prosthesis also bypasses the ossicular joints, which are thought to play a role in protecting the inner ear from large changes in static pressure within the middle ear. The prosthesis is in close proximity to the tympanic membrane, thus increasing the risk for its extrusion. We reviewed our experience with revision stapedectomy with the Schuknecht Teflon-wire malleus grip prosthesis in 36 ears with a mean follow-up of 23 months. The air-bone gap was closed to within 10 dB in 16 ears (44%) and to within 20 dB in 26 ears (72%). The incidence of postoperative sensorineural hearing loss was 8% (3 ears). There were no dead ears. Extrusion of the prosthesis occurred in 1 case (3%). Nearly 50% of patients reported various degrees of vertigo or disequilibrium during the first 3 weeks after surgery. These vestibular symptoms resolved by 6 weeks in all but 1 case. We did not find evidence of damage to the inner ear due to the length of the prosthesis or due to the potential for direct transmission of changes in static pressures within the middle ear to the labyrinth. Our results are similar to those published in the literature for malleus attachment stapedectomy and conventional revision incus stapedectomy. (+info)
Testing a method for quantifying the output of implantable middle ear hearing devices.
(3/23)
This report describes tests of a standard practice for quantifying the performance of implantable middle ear hearing devices (also known as implantable hearing aids). The standard and these tests were initiated by the Food and Drug Administration of the United States Government. The tests involved measurements on two hearing devices, one commercially available and the other home built, that were implanted into ears removed from human cadavers. The tests were conducted to investigate the utility of the practice and its outcome measures: the equivalent ear canal sound pressure transfer function that relates electrically driven middle ear velocities to the equivalent sound pressure needed to produce those velocities, and the maximum effective ear canal sound pressure. The practice calls for measurements in cadaveric ears in order to account for the varied anatomy and function of different human middle ears. (+info)
Histopathology of ossicular grafts and implants in chronic otitis media.
(4/23)
OBJECTIVES: We describe the histopathology of ossicular grafts and implants so as to provide insight into factors that may influence functional results after surgery for chronic otitis media. METHODS: Histopathologic observations were made on 56 cases: 50 surgical specimens and 6 temporal bone cases in which the graft was sectioned in situ. RESULTS AND CONCLUSIONS: Autogenous malleus, incus, and cortical bone grafts behaved in a similar manner and maintained their morphological size, shape, and contour for extended periods of time, at least up to 30 years. These histopathologic observations support the continued use of autograft ossicular and cortical bone grafts for middle ear reconstruction. Cartilage grafts developed chondromalacia with resulting loss of stiffness and showed a tendency to undergo resorption. Synthetic prostheses made of porous plastic (Plastipore, Polycel) elicited foreign body giant cell reactions with various degrees of biodegradation of the implants. Prostheses made of hydroxyapatite and Bioglass were enveloped by a lining of connective tissue and mucosal epithelium. The Bioglass material was broken down into small fragments and partially resorbed by a host response within the middle ear. These results warrant caution in the use of prostheses made of porous plastic or Bioglass. (+info)
Osseointegration of prostheses on the stapes footplate: evaluation of the biomechanical feasibility by using a finite element model.
(5/23)
Restoration of hearing is one of the main issues of tympanoplasty. Depending on the extent of destruction, the ossicular chain is partially or totally replaced by prostheses. In the unfavorable event of complete ossicular chain destruction with only the stapes footplate remaining in the oval niche, implanting of a columella prosthesis represents the gold standard. Besides ventilation problems, the main causes of unsatisfactory hearing results are dislocation of the prosthesis and poor coupling to the footplate. Therefore, stable fixation of prostheses is desirable but has not been realized to date. In line with our experimental intention to realize a bony prosthesis fixation on the footplate, we designed a finite element model for the simulation of the interacting forces once an osseointegration was achieved. These preliminary results predict the mechanical feasibility of this endeavor and the necessary general preconditions, which have to be carefully considered. A specially designed titanium prosthesis anchor needs a minimal bony fixation of 104 microm accretion height on the footplate to withstand all emerging forces. Therefore, providing a sort of artificial stapedial suprastructure in the form of a firm, preferably bony, integration of a prosthesis anchor on the footplate seems to be realistic and worthwhile from a mechanical and medical point of view. (+info)
Stapes surgery in residency: the UFPR clinical hospital experience.
(6/23)
Surgery of the stapedius remains the established treatment for otosclerosis. Recent publications have showed that success in surgeries done by residents have decreased and hearing results are worse than those obtained by experienced otologic surgeons. AIM: To evaluate the experience of the otorhinolaryngology unit, Parana University, relative to stapes surgery done in the residency training program. MATERIAL AND METHOD: A retrospective study of 114 stapes surgeries done in the past 9 years in 96 patients. Audiometric results were analysed according to the Committee on Hearing and Equilibrium guidelines and the Amsterdam Hearing Evaluation Plots. The improvement of the airway postoperative gap and thresholds were taken into account. RESULTS: 96 patients were included, most of them female adults (67.7%) and white (93.7%). Stapedectomy was done in 50.9% of cases, mostly under local anesthesia and sedation (96.5%), using mostly the Teflon prosthesis (37.7%). The surgical success rate was 50.88%, there was an 11.4% complication rate. CONCLUSION: Postoperative hearing gains considered as surgical success were inferior to published results in the literature, done by experienced surgeons. (+info)
Human temporal bones versus mechanical model to evaluate three middle ear transducers.
(7/23)
A life-size mechanical middle ear model and human temporal bones were used to evaluate three different middle ear transducers for implantable hearing aids: the driving rod transducer (DRT), the floating mass transducer (FMT) or vibrant sound bridge, and the contactless transducer (CLT). Results of the experiments with the mechanical model were within the range of the results for human temporal bones. However, results with the mechanical model showed better reproducibility. The handling of the mechanical model was considerably simpler and less time-consuming. Systematic variations of mounting parameters showed that the angle of the rod has virtually no effect on the output of the DRT, the mass loading on the cable of the FMT has a larger impact on the output than does the tightness of crimping, and the output level of the CLT can be increased by 10 dB by optimizing the mounting parameters. (+info)
Results of stapes surgery for otosclerosis with two kinds of prosthesis in residency training.
(8/23)
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