Are suspensory ligaments important for middle ear reconstruction?

As the resolution of 3D printing techniques improves, the possibility of individualized, 3-ossicle constructions adds a new dimension to middle ear prostheses. In order to optimize these designs, it is essential to understand how the ossicles and ligaments work together to transmit sound, and thus how ligaments should be replicated in a middle ear reconstruction. The middle ear ligaments are thought to play a significant role in maintaining the position of the ossicles and constraining axis of rotation. Paradoxically, investigations of the role of ligaments to date have shown very little impact on middle ear sound transmission. We explored the role of the two attachments in the gerbil middle ear analogous to human ligaments, the posterior incudal ligament and the anterior mallear process, severing both attachments and measuring change in hearing sensitivity. The impact of severing the attachments on the position of the ossicular chain was visualized using synchrotron microtomography imaging of the middle ear. In contrast to previous studies, a threshold change on the order of 20 dB across a wide range of frequencies was found when both ligaments were severed. Concomitantly, a shift in position of the ossicles was observed from the x-ray imaging and 3D renderings of the ossicular chain. These findings contrast with previous studies, demonstrating that these ligaments play a significant role in the transmission of sound through the middle ear. It appears that both mallear and incudal ligaments must be severed in order to impair sound transmission. The results of this study have significance for middle ear reconstructive surgery and the design of 3D-printed three-ossicle biocompatible prostheses.

Hearing Status After Ossiculoplasty in Open Cavity Mastoidectomy

To evaluate the hearing outcome in canal wall down mastoidectomy with middle ear reconstruction, prospective longitudinal study was done at National Institute of ENT, Dhaka from March 2015 to September 2016. Total 22 patients were included in the study undergoing canal wall down mastoidectomy with 6 months postoperative followup. Hearing outcomes were observed and compared with the preoperative hearing tests. Among the 22 patients 9 (39.1% of subjects) patients had hearing gain, 12 (52.2%) had hearing loss and 1 (4.3%) had no change in hearing postoperatively.Although disease clearance is the main objective in canal wall down mastoidectomy, hearing gain can be achieved if combined with ossiculoplasty and tympanoplasty. The hearing gain or loss depends upon the extension of disease and status of the ossicular chain. Most patients usually experience hearing loss more than the preoperative period due to removal of ossicle or ossicles for the sake of disease clearance. Bangladesh J Otorhinolaryngol; October 2017; 23(2): 195-198

Middle ear reconstruction with a flexible prosthesis

The middle ear plays a crucial role in the quality of hearing. This complex construct performs different tasks like the protection against large air pressure input, the transmission of sound and its adaption to the inner ear impedance. Traumas, erosion by chronic otitis media or cholesteatoma, as well as other degenerative or damaging diseases, are reasons for a necessary reconstruction of specific middle ear structures. The reconstruction of the ossicular chain is very often performed by using rigid ossicular replacement prostheses made out of titanium, ceramics or bone. Tilting and dislocation of these passive implants are some of the known complications after middle ear surgery. They are related to loads at the implant coupling points in response to a tension change in the middle ear. The healing process, scar tension and ventilation problems are possible causes.To increase the sound transmission quality of total reconstructions and safety in case of pressure dependent movement of the tympanic membrane, a novel flexible total ossicular replacement prosthesis (TORP) with a silicone coated ball joint prototype was developed and investigated. Besides measurements of first middle ear transfer functions of temporal bones, the mechanical properties of the flexible TORP were examined with stress relaxation investigations.The novel silicone coated ball and socket joint TORP provides a sound transfer equivalent to the intact human middle ear at normal pressure and negative pressure in the middle ear. Together with the low stiffness values at an anatomically typical deflection of about 500 μm the prevention of a stiffening of the stapes annular ligament could be approved. Thus, improved acoustic transmission quality and reconstruction stability in comparison to common rigid titanium TORP could be determined. Nevertheless, further design improvements should be accomplished. The demonstrated flexible TORP can solve some common problems in middle ear reconstruction.

Surgical management of middle ear cholesteatoma and reconstruction at the same time

Introduction. The surgical management of cholesteatoma. You can opt for a closed technique (mastoidectomy simple) or open surgery (radical mastoidectomy). The open mastoidectomy with reconstruction of the posterior wall of the middle ear reconstruction in one surgery combines the advantages of both techniques as adequate surgical exposure, eradication of cholesteatoma and anatomical reconstruction of the middle ear structures. Objective. To evaluate the surgical results in the management of cholesteatoma with the technique of open mastoidectomy with reconstruction of the posterior wall and the middle ear in one surgery. Methods. Prospective analytical observational study conducted between 2009-2012 with patients undergoing this surgical technique in the Hospital Universitario del Valle, performing preoperative clinical monitoring and quarterly postoperative tomography and previous assessments of hearing and pre -and postoperative audiometry. Results. 45 patients were studied. Mean Postoperative follow-up was 28 months. Surgical success was achieved in 93.3% of patients as measured by clinical and radiological follow. Hearing preservation was found after reconstruction of the hearing mechanism, based on measured audiometry auditory tone average (PTA) by the statistical test for paired samples between preoperative and postoperative PTA. (95% CI -1.47 to 12.15). Residual cholesteatoma was presented in 6.6%, three to four times lower than that reported in the literature. Conclusions. This type of surgery can be considered a successful technique in the treatment of cholesteatoma in selected cases.