M.ALSHEIKH Technique: Modification to the Soft Tissue Reduction in the Baha® Attract Surgery.

To describe a modification to the Baha® Attract surgical technique that aims to enhance skin closure, create smooth skin across the surface of the wound, reduce surgery time, and improve cosmetics of the surgical site. Retrospective chart review. Patients were implanted between 2014 and 2016 at King Fahad General Hospital (KFGH) (Jeddah, Kingdom of Saudi Arabia). 20 adult patients (11 males, 9 females), all eligible for Baha® Attract system. One patient only had a previous Baha® surgery. The normal Baha® Attract surgical technique with modification to the soft tissue reduction stage is described. The mean surgical time was 35.25 min (range 25-55). Bleeding was present but not significant and easily controlled in four patients. All patients received the 4 mm implant. None of the patients experienced severe pain. The postoperative follow-up period was 6 months for 7 patients and 8 months for 13 patients. Patient feedback and monitoring indicates a good hearing performance and comfort in all patients. The modified Baha® Attract surgical method causes less postoperative complication, improve cosmetic effect, and provide shorter operative time compared to the conventional Attract procedure.

Modified Baha Punch Technique: Least Invasive, Shortest Time and No Suturing.

To describe a new Baha surgical procedure (Modified Punch Technique) with a smaller punch hole, a minimal incision and the use of the hydroxyapatite-coated abutment (BIA400). Retrospective chart review. Patients were implanted between 2012 and 2013 at King Abdulaziz University Hospital (Kingdom of Saudi Arabia). Eligible for initial or replacement bone-anchored hearing system; includes six patients (four adults, two children). Baha surgery using the Punch Method is described. The mean surgical time was 12.33 min (range 6-30), without the single outlier, it was 8.8 min. Bleeding was significant but easily controlled in two patients only. Depending on the postauricular subcutaneous thickness, the sizes of abutment used were 6, 8, 10 or 12 mm. None of the patients experienced severe pain. The postoperative follow-up period was 7 months for one patient, 5 months for three patients, and 3 months for two patients. First report of combined Modified Punch Technique with the BIA400 abutment is minimally invasive, reduces surgical time and results in faster healing and reduced likelihood of postoperative numbness.

The effect of increased stiffness of the incudostapedial joint on the transmission of air-conducted sound by the human middle ear.

OBJECTIVE: To study the possible effects of increased stiffness at the incudostapedial joint (ISJ) on sound transmission in the human middle ear. BACKGROUND: The physiologic role played by the IS joint in the mechanics of human middle ear function is unclear. It is also unclear how fixation of this joint might manifest itself and what the implications are of fixing this joint during surgical reconstruction. HYPOTHESIS: Increased stiffness of the ISJ will affect sound transmission through the middle ear. METHODS: Cyanoacrylate adhesive was instilled around the ISJ joint in 5 fresh human cadaveric temporal bones to increase ISJ stiffness. Laser Doppler vibrometry measurements of sound-induced peak-to-peak displacement of the umbo and stapes footplate were made before and after stiffening the ISJ. RESULTS: At baseline, the measurements at the stapes footplate followed those at the umbo but were approximately 12 dB lower in the speech frequencies. We found that stiffening the ISJ produced an almost equal decrease in peak-to-peak displacement at both the umbo and the stapes footplate, with little change in their relative motion, consistent with an increase in ossicular impedance. The decrease was mainly between 400 and 1,000 Hz with a statistically significant mean magnitude loss of 6 dB at 740 Hz. CONCLUSION: Increased stiffness at the ISJ results in a small, probably clinically insignificant decrease of 3 to 6 dB in middle ear sound transmission in the lower frequencies between 400 and 1,000 Hz.

Prosthetic reconstruction from the tympanic membrane to the stapes head or to the stapes footplate? A laser Doppler study.

BACKGROUND: In the absence of the incus, many surgeons believe that reconstruction from the tympanic membrane to the stapes head is more effective than reconstruction to the stapes footplate. This has rarely been tested empirically. Published better clinical results with reconstruction to the stapes head might simply reflect less underlying disease in ears with an intact stapes superstructure. OBJECTIVE: To compare vibration transmission of these two forms of prosthetic reconstruction. METHODS: A fresh human cadaveric temporal bone model was used. Round window vibrations in response to sound in the ear canal were measured with a laser Doppler vibrometer. After incus removal, the discontinuity was repaired using a titanium prosthesis. Reconstruction from the tympanic membrane to the stapes head was compared to reconstruction to the stapes footplate. RESULTS: Reconstruction of both types decreased round window vibrations by 10 to 15 dB between 500 and 3000 Hz compared to the intact middle ear. Reconstruction to the stapes head performed 5 to 10 dB better at lower frequencies (500-2000 Hz), but this was only statistically significant at 1 and 2 kHz. CONCLUSIONS: There is only a 5 to 10 dB mechanical advantage gained by reconstruction from the tympanic membrane to the stapes head compared to reconstruction to the footplate for frequencies between 1 and 2 kHz.

Effect of Silastic sheeting over the round window niche on sound transmission in the intact human middle ear.

BACKGROUND: Silastic sheeting is commonly used in middle ear surgery to prevent the formation of adhesions between the tympanic membrane and the medial bony wall of the middle ear cavity. This sheeting is often placed, advertently or inadvertently, so as to cover the round window niche. The effects of mechanically shielding the round window niche in the presence of an intact tympanic membrane and ossicular chain have not been empirically studied to date. OBJECTIVE: To investigate the effect of acoustically shielding the round window with 1 mm thick Silastic sheeting on middle ear sound transmission in otherwise intact cadaveric human temporal bones. METHODS: Using a fresh human cadaveric temporal model, a computerized laser Doppler vibrometry system was used to measure vibrations at the umbo and on the stapes footplate in response to sound introduced into the ear canal. Stapes displacement was used as a measure of sound transmission. The measurements were repeated after shielding the round window using 1 mm thick Silastic sheeting. RESULTS: We found that shielding the round window with Silastic produced no significant difference in the measurements at the stapes footplate. At the umbo, a slight increase in vibrations at 250 to 500 Hz was measured after shielding. This was on the order of 3 dB and was not statistically significant. CONCLUSION: In the presence of an intact tympanic membrane and ossicular chain, shielding the round window with Silastic sheeting has no clinically significant effect on sound transmission by the human middle ear.

Linearity and lever ratio of the normal and reconstructed cadaveric human middle ear.

HYPOTHESIS: The linearity and the level ratio are different in reconstructed ears. BACKGROUND: The linearity of the reconstructed human middle ear (ME) has not been previously explored. It is important to analyze if high sound pressure levels (SPLs) result in distortion due to nonlinearities particularly because hearing aids have high-output SPLs. The diseased ME is reconstructed with prostheses. These diseased ears frequently need additional amplification with hearing aids, and it is unclear if reconstruction itself leads to nonlinear ME responses. METHODS: Eight fresh human cadaveric temporal bones were used. Pure tones of 70, 90, and 110 dB SPL at 500, 1,000, and 3,000 Hz were presented to the ear canal. Umbo and stapes displacements were measured by means of a laser Doppler vibrometer. After removing the incus, the tympanic membrane assembly to the stapes head prosthesis was placed, and measurements were repeated. RESULTS: Stapes footplate vibrations in the reconstructed ears are 10 to 15 dB lower than those of the normal ears. In both normal and reconstructed ears, the footplate vibrations are linearly related to SPL at the tympanic membrane between 70 and 110 dB SPL at the frequencies tested. For the lever ratio, intact ears are more efficient at transmission of umbo vibrations to the stapes compared with reconstructed ears. CONCLUSION: To within acceptable limits, the ME seems to be linear between 70 and 110 dB SPL input levels, across the speech frequencies, and this does not change with reconstruction. The reconstructed human ME seems to have a less efficient lever ratio than the intact ME.

Output vibration measurements of bone-anchored hearing AIDS.

HYPOTHESIS: Different bone-anchored hearing aids (BAHAs) processors have different output vibration characteristics, which depend on the mechanical load and the volume setting. Responses will differ between live heads and dry or plastic skulls. BACKGROUND: The BAHA is an implantable bone-conduction device. Three different BAHA models are available. Their output vibrations have not been reported using a noncontact method with differing impedance loads, including the BAHA-fitted patient head. METHODS: Using a laser-Doppler vibrometer, vibration responses with sound input of 70- to 80-dB sound pressure level were measured on unloaded BAHAs, a dry skull, a plastic skull, and on the abutments of three live BAHA-fitted patients. Responses at different volume settings and distances from the vibrator were also tested. Frequency responses were calculated for displacement, velocity, and acceleration. RESULTS: Unloaded BAHA accelerations were approximately 30 to 50 dB higher than live-head accelerations. Live-head accelerations were similar to dry skulls in frequencies of more than 500 Hz, but much higher than the plastic skull responses. Live-head responses were more damped. The Cordelle II outperformed the other two processors by approximately 20 dB. The Classic 300 had better low-frequency responses than the Compact. The volume settings had little effect on vibration output overall. Acceleration peak was at approximately 2.5 kHz for all conditions. CONCLUSION: The BAHA processors differ in the output acceleration they can achieve with differing loads. The volume control setting has little impact on accelerations produced for most processors. The live-head responses are similar to the dry skull in frequencies of more than 500 Hz.

Is there loss of vibration amplitude across the snap coupling of the bone-anchored hearing aid?

HYPOTHESIS: There is loss of vibration transmission across the snap coupling connecting the Bone-Anchored Hearing Aid transducer to the implanted abutment on the head. BACKGROUND: The only nonrigid part of the Bone-Anchored Hearing Aid system is the connection between the output of the transducer and the abutment. Vibration losses across the coupling have not been previously measured. If a loss is found, a change in design could improve the efficiency of the Bone-Anchored Hearing Aid. This would be very helpful in borderline cases in which the Bone-Anchored Hearing Aid does not have enough power to achieve adequate hearing threshold levels. METHODS: A laser Doppler vibrometer was used to measure vibrations on the output stem and four points on the abutment of the Bone-Anchored Hearing Aid. The Bone-Anchored Hearing Aid was coupled to a dry skull through a plexiglas bite bar screwed to the skull. The impedance load was varied by fixing the skull. A control loose coupling was measured. Five Bone-Anchored Hearing Aid Compacts were measured. RESULTS: There was little loss across the Bone-Anchored Hearing Aid snap coupling. At frequencies above 500 Hz, there was no more than 5-dB loss at any frequency. Changing the impedance load by fixing the skull did not change the loss across the coupling. CONCLUSION: The snap coupling is an efficient means of transmitting vibrations to the skull. There is little loss of vibration attenuation across it. Increases in functional Bone-Anchored Hearing Aid amplification gain cannot be achieved by further optimizing this interface.