[Biomechanics of the reconstructed ear ossicular chain].
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Biomechanical Phenomena↗
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Results for “Ossicular Prosthesis”
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Reconstruction of the ossicular chain with titanium implants.
OBJECTIVES: Since 1994 more than 1300 titanium implants have been used to reconstruct the ossicular chain of the middle ear for chronic otitis media. Two different types of implants were used. First, a total and a partial implant of fixed length, available in numerous different lengths. And second, a total and partial implant that has an adjustable length. The implants are commercially available from 2 different companies. Patients were followed for a postoperative term from 6 to 72 months. METHODS: A wide variety of patients aged 5 to 82 years received a tympanoplasty type III. Those patients whose ossicular chain had been reconstructed with titanium implants since 1994 were evaluated. As implants from one company are fixed in length; implants of a second company are trimmable in length. All prostheses are lightweight and made of pure titanium, fitting most anatomical situations. RESULTS: Earlier results already showed a very low complication rate. Extrusions occurred only in cases of middle ear atalectasis with resorption of interposed cartilage (<1%). No adverse reaction to the prostheses could be seen, even in histologic reviews. An average air-bone gap less than 20 dB(A) for all calculated frequencies of 0.5, 1, 2, and 4 kHz was achieved for 76% of cases; 43% of cases showed a calculated air-bone gap of less than 10 dB(A), only 10% higher than 30 dB(A). CONCLUSION: All implants used offer the proven benefits of titanium, namely high biocompatibility and high stability at a very low complication rate with excellent hearing results for the patients. Titanium implants can highly be recommended to reconstruct the ossicular chain of the middle ear.
Adolescent↗
[Reconstruction of the ossicular chain].
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Hearing Loss, Conductive↗
[New methods of type II tympanoplasty in erosion of the long incus process].
Reliable methods of reconstruction of the ossicular chain in the situation of an isolated errosion of the long process of the incus using a tympanoplasty type II have not been available until recently. Instead, the tympanoplasty type III has been generally performed with the interposition of an autologous incus. In this presentation, we are describing two methods for reconstruction of the ossicular chain between the in-situ residing incus and the stapes on the other side so that the direct connection eventually will result in a tympanoplasty type II. In the first case, we used ionomeric cement in a way that features two characteristics: the direct connection between the stapes and the long process of the incus could be achieved as well as an articulation that was created on the head of the stapes. Hence, a too stiff connection between the head of the stapes and the long process of the incus could be avoided. In addition, a new method for precise microapplication of cooled bone cement (IONOCAP LV) with a syringe will be presented. In the second method titanium-gold-angle prostheses have been crimped to the long process of the incus and positioned onto the head of the stapes in the way of an articulation. So far, comparison of the audiological results of those two methods of a tympanoplasty type II reveal in average better results than postoperative conductive hearing thresholds of the conventional tympanoplasty type III. If the achieved results can be reproduced on a larger number of patients, the expected audiological results are likely to resemble those of stapes surgery.
Auditory Threshold↗
Reporting of results of surgery for conductive hearing loss.
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Audiometry, Pure-Tone↗
[Pitfalls in ossicular chain reconstruction].
Today, the reconstruction of the ossicular chain is standard in middle ear surgery. It is performed as a one step procedure in cases of non-inflamed middle ears, as well as in cases of chronic ear diseases. In contrast to the past, a large tympanic cavity is today regularly reconstructed, which contributes to a normally ventilated middle ear. Reconstruction of the ossicular chain is necessary to keep the tympanic membrane in its normal position.However, many modern prostheses are available with different designs and material properties. This article aims to give an overview of the acusto-mechanical and surgical aspects of ossicular chain reconstruction. After a description of normal middle ear vibration, the biomechanical background of the reconstructed middle ear (incus reconstruction, stapes reconstruction) is discussed.
Ear Diseases↗
[Rehabilitation of high frequency hearing loss: use of an active middle ear implant].
BACKGROUND: In spite of modern technology conventional hearing aids are only helpful in a limited number of patients with sensorineural hearing loss. In particular, patients presenting with moderate to severe high frequency hearing loss but only mild hearing loss in the low frequencies suffer from problems associated with conventional hearing aids such as occlusion of the ear canal and feedback. The aim of the study was the evaluation of rehabilitation of patients with high frequency hearing loss with the active middle ear implant Vibrant Soundbridge. PATIENTS AND METHODS: The Vibrant Soundbridge was surgically implanted into 30 patients, and the floating mass transducer was clipped onto the long process of the incus. Out of the 30 patients 9 presented with a ski slope audiogram of high frequency hearing loss of 25 dB within 1 octave in the frequency range 1000-8000 Hz. Main outcome measures were pure tone audiometry, speech audiometry in quiet and in noise. RESULTS: Residual hearing was preserved in all cases. Functional hearing gain was in proportion to the individual hearing losses and was remarkably high in the high frequencies up to 8000 Hz. Mean functional gain was 34 dB in the frequencies between 2000-8000 Hz. Speech recognition scores in quiet and in noise were significantly higher with the implant compared to the unaided situation. CONCLUSION: The middle ear implant Vibrant Soundbridge has been shown to be perform extremely well especially in the high frequencies. It offers a new solution for rehabilitation of high frequency hearing loss.
Adult↗
Value of digital volume tomography in patients with conductive hearing loss.
Digital volume tomography (DVT) is an extension of panoramic tomography. With this diagnostic technique, characterized by high resolution, a narrow section width (0.125 mm) and three-dimensional display, small pathological processes can be well visualized. Twenty-five patients with the history of a progressive hearing loss were examined with DVT (Accu-I-tomo, Morita, Japan). The results were compared with pre- and intraoperative findings to evaluate the diagnostic value of DVT in cases of erosion of the ossicular chain. With high resolution and artifact-free demonstration of the middle ear and the ossicular chain, it was possible to define its continuity preoperatively by DVT in all 25 cases. An intact ossicular chain was found by DVT in 13 cases and was later confirmed by surgery. The predicted erosion of the ossicles was verified in 12 patients, and a tympanoplasty type III was performed. Digital volume tomography is an excellent technique to examine the middle ear cleft and inner ear, and expands the application of diagnostic possibilities in the lateral skull base. Therefore, improvement in preoperative diagnosis is achieved along with more accurate planning of the surgical procedure. Digital volume tomography delivers a small radiation dose with a high resolution and a low purchase price for the equipment.
Adult↗
Laser soldering and welding for ossicular reconstruction: an in vitro test.
To evaluate the possibility of laser application in ossicular reconstruction, soldering and welding of bony tissue with proteineous materials was performed by using a CO (2) laser, and the bonding strength of these materials was measured with a gradual weighing system. The soldered and welded surface of bone was observed with a scanning electron microscope. Additionally, welding of human ossicles and synthetic materials was experimentally tried with lasers, and morphologic changes were observed and recorded. A scanning electron microscopic examination was also done. A 40% albumin solution and commercial fibrin glue showed the best bonding strength. Bridging of denatured protein solder may be a mechanism of bonding. Polycel was melted by using a laser beam, and melted Polycel covered the surface of the ossicle. However, the bonding strength was not enough to use, and exact measurement of bonding strength was not possible. These results suggested the possibility of laser soldering and welding in ossicular reconstruction, especially with ossicle or cortical bone.
Animals↗
Surgical management of the atelectatic ear.
OBJECTIVE: The surgical management of the atelectatic ear is controversial because the natural course toward cholesteatoma development cannot be predicted, and hearing acuity remains normal until later in the disease course. Consequently, surgery is often delayed until there is a clear indication, such as hearing loss or frank cholesteatoma development, but such delay often necessitates more extensive surgery. Because earlier intervention appears to be in the best interest of the patient but is often avoided because of near normal hearing levels at this stage, the author proposes a staging system for classification and management of the atelectatic ear. Hearing results and complications in patients undergoing tympanoplasty with or without ossicular reconstruction are reported for patients with type III and IV retractions. STUDY DESIGN: A retrospective study using a computerized otologic database to identify patients who meet the inclusion criteria. SETTING: A tertiary referral center. PATIENTS: A total of 55 patients (63 ears) aged 5 to 78 years underwent cartilage tympanoplasty with or without ossicular reconstruction. INTERVENTIONS: Elevation of the ear drum, followed by cartilage reconstruction of the tympanic membrane, with ossicular reconstruction as indicated. MAIN OUTCOME MEASURES: Postoperative pure tone average air-bone gap for four frequencies (500, 1000, 2000, 4000 Hz) compared with preoperative levels. RESULTS: There was a statistically significant improvement in hearing (p < 0.05). CONCLUSIONS: This staging system offers an effective treatment algorithm for pars tensa retractions and management of type III and IV retractions via cartilage tympanoplasty with or without ossicular reconstruction and is a proven treatment modality.
Adolescent↗
Ossiculoplasty: a UK survey.
The aim of this study was to assess and quantify the current surgical practice of ossiculoplasty among British otolaryngology consultants, using a postal questionnaire. Ossiculoplasty is not a very common procedure. It is only performed by otologists with a special interest in ossiculoplasty. Among the 280 respondents (response rate 51.9 per cent), only 179 (63.9 per cent) performed ossiculoplasty. The majority of the consultants (86.5 per cent) used artificial prostheses, and 63.7 per cent used patients' own ossicles (autografts). Most of the consultants (77.6 per cent) performed ossiculoplasty with primary tympanoplasty surgery rather than with primary cholesteatoma surgery (46.3 per cent). The majority of the consultants (50.8 per cent) performed less than 10 ossiculoplasties per year. This is the first survey on ossiculoplasty surgery in the United Kingdom.
Attitude of Health Personnel↗
Xenogeneic ossicular implants: an experimental study of heterotopic, demineralized, lyophilized, porcine implants in the guinea-pig.
This study was done to compare the outcome of porcine ossicular implants in the middle ear and the subcutaneous dorsal region of the guinea-pig to those of allo-implants implanted in parallel in the dorsal region. The implants were heteropic, xenogeneic, demineralized (HCl), lyophilized and sterilized. The evaluation was histological (light microscopy and scanning electron microscopy) and immunological (immunofluorescence staining). Fifty-four guinea-pigs were implanted in the middle ear and 14 of them were also implanted subcutaneously in the dorsal region with xeno-implants and allo-implants. The middle ear implants were found to be constantly reossified and coated with normal mucosa with only a minimal immune reaction. In contrast, the dorsal xeno-implants were found to be the target of mononucleic infiltration, fibrous encapsulation and an influx of immunoglobulins resulting in segregation. The corresponding allo-implants were found to be partially reoccupied and reossified. These findings highlight the value of HCl demineralization in the induction of non-species-specific Bone Morphogenetic Protein and the failure of attempts at immuno-despecification. It appears that the fate of the implant depends less on its antigenic load than on the site of implantation. In this regard the middle ear is apparently very advantageous. The very good short-term tolerance and recovery observed in the middle ear xeno-implant suggest that these implants offer sufficiently good results to warrant clinical testing.
Animals↗
[Animal experiments and cell culture studies on stapes reconstruction with diverse biomaterials].
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Aluminum Oxide↗
[Toxicity of glass ionomer cement].
BACKGROUND: The hybrid bone substitute ionomeric cement achieves a stable and durable space-free bond to adjacent bone during hardening. Clinical studies have evaluated the material differently: Fully hardened ionomeric cement showed in middle ear surgery, e.g. as an ossicular prosthesis, good biocompatibility with outstanding functional results. In a few cases, freshly mixed ionomeric cement led to severe complications after contact with CSF in skull base surgery. Therefore we intended to evaluate the influence of early fluid contact on the quality of cement and to define the interval for a safe application of the material, using a cell culture model. Further we intended to investigate whether combining cement with homologous and alloplastic materials influenced its quality. METHODS: 1) Ionomeric cement (Ionocem) test bodies were placed in Ringer's solution at different times after the mixing phase. 2) Ionomeric cement (Ionocem) test bodies were coated with different clinically used homologous and alloplastic materials during the setting and hardening phase. The concentrations of released cement-forming ions and the toxic effects on mouse fibroblasts within cell cultures were measured. RESULTS: Cytotoxic effects were observed when ionomeric cement was not carefully protected from fluid contact for the first two hours after mixing. This was due to forced fast elution of large amounts of cement-constituting fluoride ions and aluminium ions and to the development of acid valences and their interactions. A total hardening time of less than 25 min had an especially unfavourable influence on cell behaviour. Cell impairments could be reduced significantly by coating the 30-minute cured cement with PDS sheeting and significantly by covering it with viscous collagene. On the other hand, cement toxicity was intensified in part by combinations with some other coating materials. CONCLUSIONS: Ionomeric cement should be kept dry and protected from any fluid contact for at least 30 minutes after mixing. Contact with soft tissue should also be avoided for this time. With a hardening time of 30 minutes, the quality and biocompatibility of glass ionomeric cement could be substantially optimized by coating it with PDS sheeting. These results should be verified in animal experiments and clinical trials.
Animals↗
Evaluation of hydroxyapatite ossicular chain prostheses.
Hydroxyapatite (HA) middle ear prostheses have gained popularity as an alternative to human autografts and homografts. This study reports on 3 HA prostheses types: total ossicular chain prostheses, used for grafting the stapes footplate to the tympanic membrane; partial ossicular chain prostheses, used for grafting the stapes superstructure to the tympanic membrane; and Kartush incus struts (Smith & Nephew Richards Inc), used for grafting the stapes superstructure to the undersurface of the malleus. This single-surgeon study of 33 consecutive cases revealed a statistically significant difference in mean postoperative air-bone gap and airbone gap closure between incus struts (14/26 dB) or partial (22/11 dB) or total (25/10 dB) ossicular chain prostheses (t test: P<0.05). Prognostic risk factors graded by the Middle Ear Risk Index indicate a tendency for worse postoperative hearing with increasing Middle Ear Risk Index. This study supports the use of HA ossicular prostheses and, in particular, the use of the malleus for ossicular chain construction.
Adult↗
International consensus on middle ear implants.
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Adult↗
Functional results of Plastipore prostheses for middle ear ossicular chain reconstruction.
OBJECTIVE: Assessment of plastipore prostheses for middle ear ossicular chain reconstruction. Hearing results with total and partial Plastipore ossicular replacement prostheses (TORP and PORP) were evaluated in open- and closed-cavity operations. STUDY DESIGN: A retrospective review of 237 patients who underwent operation for chronic ear disease as well as ossiculoplasty with plastipore prostheses. In order to assess the functional results, only 156 of 237 patients were included in the study. Follow-up ranged from 6 to 46 months. METHODS: Canal wall up and canal wall down operations were performed. Either TORP or PORP ossiculoplasty was performed in each operation. An airbone gap closure to within 20 dB was considered successful. RESULTS: With TORPs, the airbone gap closure to within 20 dB was achieved in 43.1%, and similar results were obtained with PORPs in 63.3%. In canal wall down and canal wall up operations, the success rates were 55.8% and 55.7%, respectively. The best results were obtained with PORPs in canal wall down operations, with a success rate of 82%. The extrusion rate of the prostheses was 4.2%. CONCLUSION: Hearing results of PORPs are better than TORPs. In canal wall up and canal wall down operations similar hearing results are obtained. PORP ossiculoplasty in a canal wall down operation yields the most favorable hearing result.
Adolescent↗
Gold and titanium in the oval window: a comparison of two metal stapes prostheses.
OBJECTIVE: The objective of this study was to evaluate the hearing results of stapes surgery with 2 different full metal stapes prostheses. STUDY DESIGN: Retrospective analyses were carried out on the pre- and postoperative hearing results obtained after primary stapedotomy with 2 different prostheses. PATIENTS: We studied 106 patients with otosclerosis treated by stapes surgery. INTERVENTION: Fifty-three patients had a stapedotomy with a gold piston and 53 patients received a titanium piston after stapedotomy. MAIN OUTCOME MEASURES: The results were compared according to mean audiometric parameters. Furthermore, the individual audiologic results were demonstrated with the Amsterdam Hearing Evaluations Plot (AHEP). This method is a visual presentation of the hearing result for each operated ear. RESULTS: These AHEPs showed that the heavier gold piston (shaft Ø 0.4 mm and weight 10192.0 microg) gives more overclosure gain (28.3%) than the lightweight (shaft Ø 0.4 mm and weight 2541.0 microg) titanium piston (9.4% cases of overclosure). CONCLUSIONS: Because of the different properties of the 2 pistons (gold very malleable, titanium rather stiff), a choice can be made for different anatomic or pathologic situations in the operated middle ear. The "overclosure effect" of the gold piston is higher compared with the titanium piston.
Adult↗