TYPE III TYMPANOPLASTY: A COMPARATIVE STUDY BETWEEN AUTOLOGOUS INCUS AND TRAGAL CARTILAGE AS OSSICULOPLASTY MATERIAL – OUR EXPERIENCE

Background: Type III tympanoplasty involves complete disease clearance from middle ear cleft and retaining or improving the serviceable hearing by ossiculoplasty. Various auto and allografts have been used with variable outcomes. The objective of the study was to evaluate hearing improvement in patients who underwent type III tympanoplasty using autologous incus and tragal cartilage as ossiculoplasty material. Method: A retrospective chart review of 30 patients who underwent type III tympanoplasty at medical college Srinagar Pauri Garhwal from January 2019 to December 2019 was done. In 10 patients autologous incus and in 20 tragal cartilage was used for ossiculoplasty. Those patients who required wall down were excluded from the study and only patient with limited atticotomy and complete mastoidectomy requiring type III tympanoplasty were included in the study. Pure tone audiograms done after 3 months were compared with the pre operative audiogram. Result: 10 patients who underwent type three tympanoplsty with use of autologous incus for ossiculoplasty had a mean hearing gain of 17.08dB and 20 pateint underwent type three tympanoplasty with use of tragal cartilage for ossiculoplasty had mean hearing gain of 18.26 dB at 3 months after surgery. Hearing gain was similar in both groups irrespective of the material used. The tragal cartilage was used as strut extending from stapes head to the anteroinferior part of annulus supporting the graft throughout and additionally helping in maintaining the middle ear space. Conclusion: The post-operative hearing gain with autologous incus and tragal cartilage as middle ear prosthesis are similar but the additional role of cartilage supporting the graft and maintaining the middle ear space overrule the use of tragal cartilage for ossiculoplasty in type three tympanoplasty. So by this study we recommend the use of tragal cartilage as ossiculoplasty material for type III tympanoplasty over other material.

Study on the Prosthesis Structural Design and Vibration Characteristics Based on the Conduction Effect of Human Middle Ear

As a bridge from the sound signal in the air to the sound perception of the inner ear auditory receptor, the tympanic membrane and ossicular chain of the middle ear transform the sound signal in the outer ear through two gas-solid and solid-liquid conversions. In addition, through the lever principle formed by three auditory ossicle structure, the sound was concentrated and amplified to the inner ear. However, the sound transmission function of the middle ear will be decreased by disease, genetic, or trauma. Hence, using middle ear prosthesis to replace the damaged ossicles can restore the conduction function. The function realization of middle ear prosthesis depends on the vibration response of the prosthesis from the tympanic membrane to the stapes plate on the human auditory perception frequency, which is affected by the way the prosthesis combined with the tympanic membrane, the material, and the geometric shape. In this study, reasonable prosthetic structures had been designed for different types of ossicular chain injuries, and the frequency response characteristics were analyzed by the finite element method then. Moreover, in order to achieve better vibration frequency response, a ball structure was designed in the prosthesis to simulate its amplification function. The results showed that the middle ear prostheses constructed by different injury types can effectively transfer vibration energy. In particular, the first- and second-order resonant frequencies and response amplitudes are close to each other when ball structure models of different materials are added. Instead, the resonance frequency of the third stage formed by aluminum alloy ball materials is larger than that of the other two, which showed good response features.

Outcomes of type III tympanoplasty: our experience

<p class="abstract"><strong>Background:</strong> Type III tympanoplasty involves complete disease clearance from middle ear cleft and retaining or improving the serviceable hearing by ossiculoplasty. Various auto and allografts have been used with variable outcomes. The objective of the study was to evaluate hearing improvement and healing of cavity in patients who underwent type III tympanoplasty.</p><p class="abstract"><strong>Methods:</strong> A retrospective chart review of 21 patients who underwent type III tympanoplasty at Bowring and Lady Curzon Hospital from January 2018 to December 2018 was done. In 7 patients autologous incus, 6 tragal cartilage and 8 teflon prosthesis was used for ossiculoplasty. Intra and postoperative events were assessed. Pure tone audiograms done after 3 and 6 months were compared. </p><p class="abstract"><strong>Results:</strong> 15 patients who underwent canal wall down procedure (CWDP) had a mean hearing gain of 20.33 dB and 26.67 dB while in 5 patients of canal wall up procedure (CWUP) group mean hearing gain was 22.5 dB and 27.5 dB at 3 and 6 months after surgery respectively. Hearing gain was similar in both groups irrespective of the prosthesis used. Autologous materials were used in most of the CWUP with intact stapes and teflon prosthesis was used in majority of CWDP where only mobile stapes foot plate was present. Prosthesis extrusion was not encountered in any of our cases so far in this series.</p><p class="abstract"><strong>Conclusions:</strong> The post-operative hearing gain with autologous incus, tragal cartilage and teflon middle ear prosthesis are similar. Teflon prosthesis is an effective material for ossiculoplasty, especially useful when incus and stapes are absent while autologous incus or tragal cartilage are preferred in cases with intact stapes head.</p>

Biological and Physicochemical Assessment of Middle Ear Prosthesis

Polymers modified with bioactive nanoparticles are a promising solution for patients who need a tissue replacement. Modern implants, thanks to bioactive and bactericidal functions, facilitate the healing and regeneration process of the replaced tissue. The aim of this study was to assess whether silver nanoparticles (AgNPs) could support antibacterial function without cytotoxic effect and deterioration of biostability. This article describes biological and physiochemical aspects concerning a new polymeric middle ear implant (Otoimplant) enriched with silver nanoparticles. This kind of prosthesis is a promising implant for the reconstruction of ossicles in ossiculoplasty. We found that incorporation of silver nanoparticles into a polymeric matrix resulted in bactericidal efficacy against Gram-positive and Gram-negative bacteria, both resistant to antibiotics and basic strains. Our prostheses do not show cytotoxic effect and are a suitable biomaterial platform for effective culture of Saos2 and NHOst osteoblastic cells. The in vitro incubation of the samples in distilled water revealed that surface parameters, such as roughness, may slightly increase as a result of unveiling nanoparticles. However, the prolonged immersion does not change mechanical parameters. During one-year incubation, the prosthesis proved to retain stable values of Young’s modulus, tensile strength, propagation of longitudinal ultrasonic waves, pH, and conductivity.

Middle ear vibrations with SMA prosthesis. Experimental research

The paper focuses on experimental research of a middle ear prosthesis made of shape memory alloy. The prosthesis provides better adjustment to individual patient than classical prosthesis. The shape memory prosthesis is implemented to a fresh temporal bone and vibrations of the round window are recorded by means of the Laser Doppler Vibrometer. Finally, the results are presented in the form of transfer function and compared to the intact and damaged middle ear.

Dynamics of SMA micro-actuator in biomechanical system

In this paper the polynomial model of shape memory alloy is used to characterise properties of a micro-actuator which is applied as a new middle ear prosthesis. A two degrees of freedom model of the reconstructed middle ear is solve by means of multiple time scales method. The system has various behaviours near the primary resonance depending on ambient temperature. The special case when relative temperature θ = 1.0 characterises untypical resonance curve. Increasing temperature to the normal human body one the resonance curves are typical. Then the system has only one periodic solution if the excitation is not too strong.