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Minimal access surgery for the Symphonix/Med-El Vibrant Soundbridge middle ear hearing implant.

OBJECTIVE: To develop a minimal access approach for implantation of the Vibrant Soundbridge middle ear hearing implant. This approach ideally uses the smallest skin incision possible, minimal or no hair shave, and the least possible amount of tissue and bone manipulation. This will facilitate the acceptability of the procedure to the general community and reduce the flap-related complication rate. The procedure is similar to the minimal access approach described for cochlear implantation. STUDY DESIGN: Eight patients with various degrees of sensorineural hearing loss and one with a mixed hearing loss who met implant criteria for the Vibrant Soundbridge middle ear hearing implant received the device over a 42-month period. The first two patients underwent the traditional implant procedure with postauricular hair shave, postauricular S-shaped incision, and implant receiver suture fixation to the temporal bone. The following seven consecutive patients received a progressively smaller C-shaped postauricular skin incision, no hair shave, retrograde skull drilling for the implant seat, and no implant suture fixation until the technique closely approximated the minimal access cochlear implant procedure. Postoperative performance of the Soundbridge/Vibrant Med-El was evaluated through audiology testing and subjective patient reports. SETTING: Private neurotology clinic and tertiary care teaching hospital. RESULTS: The technique was feasible in all patients. Follow-up for the minimal access group ranged from 3 years to 5 months. There were no complications related to the approach, and all patients were satisfied users of the implant. The lack of hair shave and small incision size was greatly appreciated and warmly endorsed by the patients. CONCLUSION: The Vibrant Soundbridge/Vibrant Med-El can be safely implanted using the minimal access method that has been popularized for cochlear implant surgery. A large incision, extensive hair shave, risk of flap necrosis, and possibility of unsightly scar may deter patients from pursuing the potential benefits of implanted hearing technology. The technique may make the device more accessible to individuals who have concerns regarding cosmetics and potential flap complications.

Adult↗

Vibrant soundbridge surgery: evaluation of transcanal surgical approaches.

UNLABELLED: Since its introduction, surgery for the placement of the Vibrant Soundbridge (VSB) device has been performed using a facial recess approach. Because of the size of the VSB device, this approach requires a large facial recess that can lead to complications, i.e., facial palsy and/or taste disturbance. The purpose of this study is to develop and compare transcanal surgical approaches for leading the VSB into the middle ear. SETTING: Cadaver temporal bones in a university temporal bone laboratory. MATERIALS AND METHODS: First, two experienced senior surgeons validated the three possible approaches in human temporal bone: 1) the classical facial recess approach; 2) a small mastoidectomy, elevation of a tympanomeatal flap, small atticotomy, 0.5-mm cutting of the bony external auditory canal (EAC) from the cortical plane on its approximately two-thirds to three-fourths and then a trough to pass the electrode array into the middle ear; and 3) similar to the second approach but with replacing the cutting of the bony EAC with a tunnel from the mastoid cavity to the EAC. Both the second and third approaches were transcanal. Next, five residents and six attending surgeons performed the three operations and evaluate these different approaches by using analog visual scales (VAS) for each procedure. They assess the following: 1) the ease of passing the electrode array and the Floating Mass Transducer (FMT) into the middle ear, 2) the ease for FMT clipping, and 3) their self-confidence using each approach. Time required for the three operations was measured. Measurements of landmarks were obtained on all temporal bones. Two patient cases illustrate the clinical application of this new surgical approach. RESULTS: The two transcanal approaches were assessed to be easier, faster, and safer methods for VSB surgery than the classic facial recess approach. CONCLUSION: VSB surgery has been performed using a facial recess approach with risk for facial nerve and taste disturbance. Transcanal approaches are good alternative for this surgery. Three major limitations are to be assessed in future patient studies: the pathologic findings of the EAC, the design of the FMT regarding the axis of the ossicular chain, the long-term evaluation of the skin of the external ear canal.

Aged↗

Magnetic properties of middle ear and stapes implants in a 9.4-T magnetic resonance field.

HYPOTHESIS: A 9.4-T magnetic resonance (MR) field may cause motion displacement of the middle ear and stapes implants not previously observed with 1.5- and 3.0-T magnets. BACKGROUND: Publications have described the safety limitations of some otologic implants in 4.7-T field and resulted in several companywide patient safety-related recalls. To date, no studies have been reported for otologic implants in a 9.4-T MR field nor have comparisons been made with 4.7-T field strengths. METHODS: Twenty-three commonly used middle ear and stapes prostheses were selected and exposed to 9.4-T MR fields in vitro within petri dishes, and eight of the 23 implants were further studied ex corpus in human temporal bones (TBs) in a 9.4-T MR field. This study has been approved by the institutional review board. RESULTS: Eight prostheses in petri dishes grossly displaced at 9.4 T, three of which had not previously moved in either the 1.5- or 3.0-T magnets. The eight TB preparations showed no avulsions or motion indicators after exposure at 9.4 T. CONCLUSION: Middle ear and stapes implants can move dramatically in petri dishes at 9.4-T MR field, more so than at 1.5 and 3.0 T. The absence of avulsions in the TB group strongly suggests that the surgical means used to fixate the middle ear implants to the middle ear structures successfully overcomes the magnetic moment produced at MR field strengths up to 9.4 T. The use of MR imaging is not contraindicated by this study's findings.

Cadaver↗

Mechanics of the TORP/stapes interface.

The gain in hearing as a result of ossicular prosthesis ( TORP ) placement on the stapes footplate was evaluated in 10 patients during actual middle ear reconstructive surgery. The patients with radical mastoidectomy cavities were operated on under local anaesthesia and intra-operative hearing was tested with the TORP shaft in three positions with regard to the stapes footplate; anterior, central and posterior. The anterior position of the shaft provided greater hearing improvement than the posterior position, with the central position falling approximately midway.

Adult↗

Audiometric evaluation of an attempt to optimize the fixation of the transducer of a middle-ear implant to the ossicular chain with bone cement.

Typically, an implantable hearing device consists of a transducer that is coupled to the ossicular chain and electronics. The coupling is of major importance. The Vibrant Soundbridge (VSB) is such an implantable device; normally, the VSB transducer is fixed to the ossicular chain by means of a special clip that is crimped around the long process of the incus. In addition to crimping, bone cement was used to optimize the fixation in six patients. Long-term results were compared to those of five controls with crimp fixation alone. To assess the effect of bone cement (SerenoCem, Corinthian Medical Ltd, Nottingham, UK) on hearing thresholds, long-term post-surgery thresholds were compared to pre-surgery thresholds. Bone cement did not have any negative effect. Next, to test the hypothesis that aided thresholds might be better with the use of bone cement, aided thresholds were studied. After correction for the severity of hearing loss, only a small difference was found between the two groups at one frequency, viz. 2 kHz. It was concluded that there was no negative effect of using bone cement; however, there is also no reason to use bone cement in VSB users on a regular basis.

Adult↗

Titanium and glass-ionomer cement as ossicular replacement materials: biocompatibility results after implantation in the rabbit.

The middle ear poses unique challenges when finding suitable materials for ossicular reconstruction, primarily because of its link to the external environment via the eustachian tube, which leads to a greater potential for exposure to infectious agents. In this animal study, the biocompatibilities of titanium and glass-ionomer cement were assessed in the middle ear of the rabbit after being implanted as total ossicular replacement prostheses (TORPs) or as free pins. Animals were sacrificed after 28, 84, 168, 336, or 504 days or 2 years, and a cutting saw technique was used to prepare slides for light microscopy. Slides were examined for mucosal coverage and any sign of foreign body reaction. Both materials showed good acceptance in the middle ear. After 28 days, the TORPs were covered by middle ear mucosa. As expected, it took a longer time (up to 504 days) to cover the free implants. An interesting finding was the growth of new bone on both the surface of the titanium implants and the glass-ionomer prostheses. The results of this animal study indicate that both titanium and glass-ionomer cement are favorable materials for ossicular replacement prostheses.

Animals↗

Retrograde mastoidectomy with canal wall reconstruction: a single-stage technique for cholesteatoma removal.

The goal of this retrospective study was to report the preliminary results of the retrograde mastoidectomy technique with canal wall reconstruction used as a primary treatment method for cholesteatoma. This synthesis of canal wall up (CWU) and canal wall down (CWD) techniques was performed in 70 patients (75 ears; 35 pediatric, 40 adult) with an average 45-month follow-up. Surgical intervention involved removal of a portion of the canal wall for exposure and extirpation of the cholesteatoma, followed by reestablishment of the canal wall during reconstruction in a single stage. This leaves the mucosa relatively undisturbed and limits the extent of canal wall removal, facilitating mastoid aeration and preservation of anatomy. Recurrent disease occurred in 5% of cases. The hearing improvement was statistically significant (p < .05), with an average preoperative 4-frequency pure tone average air-bone gap of 27.2 dB improving to 11.5 dB. No patient had a worsening of hearing. The surgery takes less time than traditional techniques, is reproducible and easily taught, and can be universally applied to all cholesteatoma patients as primary treatment.

Adolescent↗

Mass loading on the ossicles and middle ear function.

The middle ear as a levered vibrating system for sound transmission from the external to the inner ear is affected by changes in ossicular chain mass. Mass loading of the ossicles may impair ossicular dynamics and sound transmission to the inner ear. It is incumbent on otologic surgeons and researchers of middle ear mechanics to consider the mass loading effect on middle ear function in clinical and physiological applications. The residual hearing and frequency response can change after surgery or implantation of middle ear prostheses. We conducted experiments on mass loading effects on the middle ear transfer functions by using laser Doppler interferometry and a human temporal bone model. Two implant mass loading conditions were tested on 17 fresh or fresh-frozen temporal bones and compared with the unloaded condition for the frequencies 250 to 8,000 Hz. The results show that the linearity of the middle ear function did not change, although displacement of the stapes footplate decreased after the increased masses were placed on the incudostapedial joint. The greater the mass of the implant, the less displacement was measured at the stapes footplate. We conclude that there is a quantitative limit to increased mass on the ossicular chain above which the mass will remarkably impair hearing thresholds.

Adult↗

Failures with Plasti-Pore ossicular replacement prostheses.

Plasti-Pore ossicular prosthesis failures found in our series of 246 patients with regular follow-up are reported and analyzed. Extrusions as well as poor functional results (postoperative air-bone gap greater than 25 dB) of the prostheses with and without cartilage on top have been reviewed. The overall extrusion rate was 9.3%: a higher extrusion rate occurred with prostheses without cartilage (18.4%) than with cartilage (4.4%). Thirty-six patients among those with poor postoperative hearing improvement have undergone revision surgery: the main causes of failure were a short prosthesis, a fixed stapes or footplate, adhesions of the prosthesis to surrounding structures, and the displacement of the prosthesis.

Cochlear Implants↗

Osseointegrated implants in the management of childhood ear abnormalities: with particular emphasis on complications.

Little has been published about the difficulties encountered during the insertion of osseointegrated implants for the attachment of bone anchored hearing aids (BAHA) and auricular prostheses in children. This study examines this issue in the first 51 children implanted at our centre. During surgery, the most common problem encountered was the presence of thin bone resulting in incomplete insertion of fixtures. Five fixtures had failed to integrate and six fixtures were lost in the long-term, however, only five children required revision surgery. The reason why few patients require revision was due to the judicious insertion of 'sleeper' fixtures. At follow-up, seven children required counselling for psychological problems. It is apparent from this study that osseointegrated implants in children are associated with difficulties, re-emphasizing that a paediatric osseointegration programme requires significant investment, and should only be undertaken by institutions that are committed to its success.

Adolescent↗

Congenital conductive hearing loss.

Congenital conductive hearing loss due to ossicular deformities can be treated by either rehabilitation with a hearing aid or surgical reconstruction. We present the results of exploratory tympanotomy performed in a large paediatric otolaryngology centre in 67 patients with non-serous congenital conductive hearing loss. Forty-two children had malformation of one or more ossicles without fixation of the stapes, and 19 had fixed stapes. In 26 cases, the surgeon decided not to perform surgical correction. Seven operated patients were lost to follow-up. As a group, 47 per cent of the patients who underwent reconstruction showed no significant benefit from surgery, with post-operative air-bone gaps (ABG) greater than 30 dB. Assessment of the results by pathology showed that 64 per cent of the patients with mobile stapes had an air-bone gap within 30 dB compared to only 33 per cent of the patients with fixed stapes. One patient sustained severe sensorineural loss after the procedure. Considering that exploratory tympanotomy is a relatively minimal, benign procedure but that findings during exploration may exclude the option of reconstruction (in 39 per cent of our patients), we suggest exploring the ear, but in a more realistic, informed way.

Adolescent↗

Dimensions of importance in reconstructive middle ear surgery.

A study of the space available for an ossicular prosthesis is presented. Twelve temporal bones without any signs of chronic ear disease were used. The measurements were made with the bone free from soft tissue mounted on a microscope cross-table. The different distances were registered through a stereo-microscope. The width between the facial nerve canal and the promotory was found to be 2.2 mm. The distance from the footplate to the tympanic sulcus plane was found to be 6.6 mm. The space available for the head of a prosthesis was also investigated.

Aged↗

[Clinical experiences and postoperative results with partially implantable middle ear implant].

A partially implantable middle ear implant using an ossicular vibrator of a piezoelectric ceramic bimorph has recently been developed in Japan as a new rehabilitative method for hearing. Four patients at the Miyazaki Medical College Hospital were implanted with this device between September 1994 and October 1996. Implantation of the internal component was performed under local anesthesia after confirmation of sufficient sensitivity to the ossicular vibrator in an intraoperative vibratory hearing test. All patients regained socially useful hearing with the middle ear implant without any foreign body reactions or recurrence of otitis media. None of the cases showed any elevations of bone conduction thresholds 2 to 4 years postoperatively. Natural and clear sounds without interference noise and howling due to acoustic feedback were highly satisfactory in all patients. However, the first case, who had an implant in an ear following cholesteatoma surgery using the intact canal wall technique, experienced about a 10dB deterioration of the average hearing level with the implant 2 years after implantation. Gradual deterioration appeared to be caused by the retracted tympanic membrane interfering with the mobility of the ossicular vibrator. The following three cases were implanted in ears previously operated on by radical mastoidectomy, showing stable or improving hearing results with the implant. Closure of the external canal skin at the cartilaginous portion at the time of implantation seemed appropriate to maintain a sufficient middle ear space for the ossicular vibrator to work properly. Our case study confirms that the partially implantable middle ear implant is a safe and useful tool for patients with mixed deafness which cannot be satisfactorily rehabilitated by tympanoplasty and/or a conventional hearing aid.

Deafness↗

The effect of gelfilm in the prevention of fibrosis in the middle ear of the animal model.

HYPOTHESIS: Gelfilm offers protection against fibrosis in the middle ear when used in combination with Gelfoam. BACKGROUND: Gelfoam is used routinely as a support structure in the middle ear cleft when ossicular reconstruction and tympanic membrane grafts are performed. It has been recognized that fibrosis may occur in this setting if the middle ear mucosa is denuded. Materials have been used to protect the mucosa in an attempt to prevent scar bands, adhesions, and fibrosis and its potential detriment on hearing. These materials have included Teflon, Silastic, and Gelfilm. Concerns have arisen regarding this mode of therapy and its benefit. METHODS: This study looks at the effects of implanting Gelfoam independently and Gelfoam and Gelfilm concurrently in the bulla cavity of the Mongolian Gerbil. The temporal bones were harvested and evaluated histologically using hemotoxylin and eosin staining for fibrosis. RESULTS: Results demonstrated a decrease in the amount of fibrosis in the animals in which Gelfilm was used to protect the denuded mucosa. No evidence of fibroblast ingrowth or scar bands penetrating the Gelfilm was identified. CONCLUSION: These results suggest that Gelfoam can be used safely in the middle ear cleft to support ossicular prosthesis and tympanic membrane grafts when Gelfilm is used to protect denuded mucosa.

Animals↗

[Autografts versus biomaterials for ossiculoplasty with normal stapes; a comparative analysis of functional outcome in 100 cases].

Ossicular graft is usually considered as the reference for surgical substitution in ossiculoplasties. Nevertheless, according to the infectious risks, nothing but autografts or synthetic prosthetic substitutes should be used nowadays. Authors compare hearing results for 100 patients after ossiculoplasty with either ossicular autograft or calcium-phospathe chain reconstruction. Audiometric results were retreived using both Glasgow Benefit Plot study and post-operative air-bone gap thresholds closure. Significant hearing improvement was statistically demonstrated in both conditions, and 60% of the patients had a post-operative hearing gain. Autograft ossicular reconstructions did not show to provide higher results. Biocompatibility and functionnal properties of calcium-phosphate materials retreived in this study, indicate that those ceramic substitutes should be considered as the best alternative to autografts.

Adolescent↗

[Reconstruction acusticus back wall and tympanoplasty with homograft costal cartilage].

OBJECTIVE: To eliminate the back wall defect of external canal and opened mastoid cavity which was remained from radical mastoidectomy. METHOD: We performed the operation on 17 cases after radical mastoidectomy by using reconstruction of the canal wall and fill-in opened mastoid cavity and ossicular replacement prostheses made of homograft costal cartilage. The tympanoplasty had been made operated for all patients, 8 ears were PORP, the others were TORP. RESULT: All cases were followed-up for 6 months-2 years. The external canal of all patients are normal in appearance. The total effective rate of gain (> 15 dB) was 14 ears (82.4%). Only one patient whose tympanic membrane was perforated postoperation 3 months. CONCLUSION: Reconstruction of acusticus back wall and hearing after radical mastoidectomy with homograft costal cartilage is effective to prevent mastoid cavity infection and improve hearing.

Adult↗

[Application of hydroxyapatite in micro-otosurgery: experiment with guinea pigs and clinical application].

OBJECTIVE: To investigate the feasibility of hydroxyapatite (HA) middle ear prostheses in otosurgery. METHODS: In the animal experiment HA prostheses were put in the bilateral bullae of the ears of 12 healthy white guinea pigs (totally 24 ears). Three guinea pigs were killed every month 1-4 months later. Morphological examination and electron microscopy were conducted to observe grafts. In the clinical experiment HA prostheses was used in ossiculoplasty in 31 cases, reconstruction of posterior wall of external auditory canal in 5 cases, and mastoid obliteration in 11 cases. RESULTS: The HA prostheses taken out from 23 ears of the guinea pigs were with normal and complete structure, and clear margin in gross anatomy and microscopically. Only one ear suffered infection. Follow-up or the patients for 1-4 years showed excellent healing of the operated parts and an improvement of hearing threshold by about 16 dBHL. CONCLUSION: Hydroxyapatite with excellent physical and chemical properties and biological tolerance HA is a good material in ossiculoplasty, canaloplasty, mastoid obliteration, and other otological operations.

Adult↗