Middle Ear Prosthesis Research Articles

Enhancing middle ear implants: Study of biocompatible materials with hydroxyapatite coating

In this manuscript, the application of hydroxyapatite coatings to total ossicular reconstruction prostheses (TORPs) using finite element modeling simulations was investigated to enhance the biocompatibility and mechanical performance of these prosthetic devices for middle ear implants. We focused on evaluating biocompatible materials, particularly polyetheretherketone (PEEK) and titanium, by analyzing their mechanical behavior under simulated conditions. The results revealed that PEEK demonstrates mechanical performance almost on par with titanium, exhibiting excellent stability and resilience within the middle ear environment. PEEK offers several key advantages over titanium, including easier fabrication, greater availability, and a simplified application process for hydroxyapatite coatings. These benefits suggest that PEEK could be a highly effective alternative to titanium for use in middle ear prostheses. The findings of this study highlight the potential of PEEK to improve the design and functionality of middle ear implants, providing a promising direction for future research and development in this field. By leveraging the advantages of PEEK, we can advance the effectiveness and accessibility of middle ear prosthetic devices, ultimately benefiting patients requiring such interventions.

Optimizing mechanical behavior of middle ear prosthesis using finite element method with material degradation FGM in three functions

Advancements in technology have revolutionized healthcare, with notable impacts on auditory health. This study introduces a novel approach aimed at optimizing materials for middle ear prostheses to enhance auditory performance. We developed a finite element (FE) model of the ear incorporating a pure titanium TORP prosthesis, validated against experimental data. Subsequently, we applied Functionally Graded Materials (FGM) methodology, utilizing linear, exponential, and logarithmic degradation functions to modify prosthesis materials. Biocompatible materials suitable for auditory prostheses, including Stainless Steel, titanium, and Hydroxyapatite, were investigated. Our findings indicate that combinations such as Stainless Steel with titanium and Hydroxyapatite offer improved outcomes compared to pure titanium and Hydroxyapatite ceramic, in terms of both displacement and stress. Additionally, personalized prostheses tailored to individual patient needs are feasible, underscoring the potential for further advancements in auditory healthcare.

Integration of 3D-printed middle ear models and middle ear prostheses in otosurgical training

BackgroundIn otosurgical training, cadaveric temporal bones are primarily used to provide a realistic tactile experience. However, using cadaveric temporal bones is challenging due to their limited availability, high cost, and potential for infection. Utilizing current three-dimensional (3D) technologies could overcome the limitations associated with cadaveric bones. This study focused on how a 3D-printed middle ear model can be used in otosurgical training.MethodsA cadaveric temporal bone was imaged using microcomputed tomography (micro-CT) to generate a 3D model of the middle ear. The final model was printed from transparent photopolymers using a laser-based 3D printer (vat photopolymerization), yielding a 3D-printed phantom of the external ear canal and middle ear. The feasibility of this phantom for otosurgical training was evaluated through an ossiculoplasty simulation involving ten otosurgeons and ten otolaryngology–head and neck surgery (ORL-HNS) residents. The participants were tasked with drilling, scooping, and placing a 3D-printed partial ossicular replacement prosthesis (PORP). Following the simulation, a questionnaire was used to collect the participants' opinions and feedback.ResultsA transparent photopolymer was deemed suitable for both the middle ear phantom and PORP. The printing procedure was precise, and the anatomical landmarks were recognizable. Based on the evaluations, the phantom had realistic maneuverability, although the haptic feedback during drilling and scooping received some criticism from ORL-HNS residents. Both otosurgeons and ORL-HNS residents were optimistic about the application of these 3D-printed models as training tools.ConclusionsThe 3D-printed middle ear phantom and PORP used in this study can be used for low-threshold training in the future. The integration of 3D-printed models in conventional otosurgical training holds significant promise.

Visualization of bone formation in sheep’s middle ear by using fluorochrome sequential labelling (FSL)

One factor for the lacking integration of the middle ear stapes footplate prosthesis or the missing healing of stapes footplate fractures could be the known osteogenic inactivity. In contrast, it was recently demonstrated that titanium prostheses with an applied collagen matrix and immobilised growth factors stimulate osteoblastic activation and differentiation on the stapes footplate. Regarding those findings, the aim of this study was to evaluate the potential of bone regeneration including bone remodeling in the middle ear. Ten one-year-old female merino sheep underwent a middle ear surgery without implantation of middle ear prostheses or any other component for activating bone formation. Post-operatively, four fluorochromes (tetracycline, alizarin complexion, calcein green and xylenol orange) were administered by subcutaneous injection at different time points after surgery (1 day: tetracycline, 7 days: alizarin, 14 days: calcein, 28 days: xylenol). After 12 weeks, the temporal bones including the lateral skull base were extracted and histologically analyzed. Fluorescence microscopy analysis of the entire stapes with the oval niche, but in particular stapes footplate and the Crura stapedis revealed evidence of new bone formation. Calcein was detected in all and xylenol in 60% of the animals. In contrast, tetracycline and alizarin could only be verified in two animals. The authors were able to demonstrate the osseoregenerative potential of the middle ear, in particular of the stapes footplate, using fluorescence sequence labelling.

Multichannel multimodal piezoelectric middle ear implant concept based on MEMS technology for next-generation fully implantable cochlear implant applications

This paper introduces a unique multimode, multichannel piezoelectric vibration sensor for the next-generation fully implantable cochlear implant (FICI) systems. The sensor, which can be implanted on the middle ear chain to collect and filter the ambient sound in eight frequency bands, comprises an array of 4 M-shape multimode and 11 single cantilevers. Finite element (FE) analysis indicates a 2.05-fold improvement in capturing frequency information for the multimodal sensor compared to its single-mode counterpart. Under an acoustic excitation at 100 dB SPL, the sensor, mounted on an artificial tympanic membrane, yielded a peak output voltage of 546.16 mVpp and a peak sensitivity of 285.28 mVpp/Pa at 1613 Hz. The extrapolated acoustic results indicated a dynamic frequency range between 300 Hz and 6 kHz, even at 30 dB SPL. Furthermore, a lightweight titanium coupler, employing a two-sided clipping structure with a maximum wall thickness of 70 μm, is micromachined for surgical attachment of the transducer to the middle ear chain. A commercial accelerometer, implanted on the incus short process (SP) of a cadaver using the titanium coupler, successfully recorded 0.1 g for 100 dB SPL at 500 Hz, revealing the potential feasibility of the coupler for vibration sensor implantation. Moreover, the presented anatomically accurate FE model of the middle ear, exhibiting a high correlation coefficient (R2) of 0.97 with the cadaveric experiment, suggests an efficient numerical approach for evaluating the implantation of middle ear prostheses. In this regard, the study holds great promise for clinical application in the field of implantable hearing aids.

Evaluation and Comparison of the Mechanical Behaviors of a Middle Ear Prosthesis using the Finite Element Method

Evaluation and Comparison of the Mechanical Behaviors of a Middle Ear Prosthesis using the Finite Element Method

Partial Ossicular Reconstruction With a Novel Ball Joint Prosthesis: The mCLIP ARC Partial Prosthesis.

Middle ear surgery involves reconstruction of the ossicular chain, predominately using rigid implants. New middle ear prostheses strive to mimic the physiologic micromovements of the ossicular chain and prevent dislocation, protrusion, and preloading of the annular ligament due to pressure fluctuations. Thirty-five patients were included in a monocentric, prospective observational study. Patients received tympanoplasty with ossicular reconstruction using the mCLIP ARC partial prosthesis. This titanium prosthesis is equipped with a clip mechanism for coupling at the stapes and a ball joint connecting headplate and shaft. At short-term (ST) and mid-term (MT) follow-up, pure-tone audiometry was performed and the pure tone average of 0.5, 1, 2, and 3 kHz (PTA4) was calculated. The audiological outcome was compared with retrospective data of the Dresden titanium clip prosthesis. The new prosthesis shows favorable clinical results. Pure-tone audiometry showed satisfactory results in ST and MT follow-up, with the PTA4 air-bone gap (ABG) decreasing from 24.5 (±11) dB to 17.4 (±7.9) dB at the ST follow-up at 27 days to 15.6 (±10.3) dB at MT follow-up at 196 days (n = 32). A PTA4-ABG value of less than 20 dB was achieved by 63% of patients at ST follow-up and by 77% at MT follow-up. There was no significant difference in PTA4 ABG compared to the Dresden titanium clip prosthesis during ST follow-up (p = 0.18). The mCLIP ARC partial prosthesis, a new middle ear prosthesis with a balanced ball joint, shows promising audiological results and is a safe and effective choice for patients with chronic ear disease. 3 Laryngoscope, 134:3323-3328, 2024.

Modern Trends in Otologic Surgery and Implications for Residency Training.

Placing a middle ear prosthesis is considered a key competency for the general otolaryngologist, but surgeons struggle to obtain and maintain this skill. The current study aims to characterize pre-coronavirus disease 2019 trends in stapedectomy and ossiculoplasty. Database review. Tricare beneficiaries are treated at civilian and military facilities. The Department of Defense beneficiary population of more than nine million persons per year was reviewed for patients undergoing either stapedectomy or ossiculoplasty between 2010 and 2019, identified by the current procedural terminology code. A total of 3052 stapedectomies and 7197 ossiculoplasties were performed. Over the 10-year study period, stapedectomy decreased by 23%, with an average annual rate of -2.7% per year (Pearson r = -.91, P = .0003). Ossiculoplasties declined by 18%, an average annual rate of -1.9% (r = -.8, P = .006). In combination, cases declined by 20%, an average annual rate of -2.2% (r = -.87, P = .001). While declines in stapedectomy surgery have been well reported, here we show steady declines in ossiculoplasty as well. If these trends continue, more cochlear implantations may be performed annually than stapedectomy and ossiculoplasty combined, with cochlear implantation likely to overtake ossicular chain surgery in the near future. These changes in surgical volume have a direct implication on resident education and general otolaryngology expectations after graduation. Strong consideration should be made to replace "Stapedectomy/Ossiculoplasty" as resident key indicator with "Cochlear Implantation," a more professionally meaningful skill.

Performance of personalised prosthesis under static pressure: Numerical analysis and experimental validation

This study investigates the performance of personalised middle ear prostheses under static pressure through a combined approach of numerical analysis and experimental validation. The sound transmission performances of both normal and reconstructed middle ears undergo changes under high positive or negative pressure within the middle ear cavity. This pressure fluctuation has the potential to result in prosthesis displacement/extrusion in patients. To optimise the design of middle ear prostheses, it is crucial to consider various factors, including the condition of the middle ear cavity in which the prosthesis is placed. The integration of computational modelling techniques with non-invasive imaging modalities has demonstrated significant promise and distinct prospects in middle ear surgery. In this study, we assessed the efficacy of Finite Element (FE) analysis in modelling the responses of both normal and reconstructed middle ears to elevated static pressure within the ear canal. The FE model underwent validation using experimental data derived from human cadaveric temporal bones before progressing to subsequent investigations. Afterwards, we assessed stapes and umbo displacements in the reconstructed middle ear under static pressure, with either a columella-type prosthesis or a prosthetic incus, closely resembling a healthy incus. Results indicated the superior performance of the prosthetic incus in terms of both sound transmission to the inner ear and stress distribution patterns on the TM, potentially lowering the risk of prosthesis displacement/extrusion. This study underscores the potential of computational analysis in middle ear surgery, encompassing aspects such as prosthesis design, predicting outcomes in ossicular chain reconstruction (OCR), and mitigating experimental costs.

Titanium Biohybrid Middle Ear Prostheses: A Preliminary In Vitro Study.

Ossiculoplasty is a surgical operation performed to restore auditory transmission through the reconstruction of the ossicular chain using prosthetics. Tissue bioengineering has assumed a pivotal role in implementing alternatives to conventional ossicular middle ear replacement prostheses, to overcome extrusion while preserving acoustic properties. This in vitro study aims to explore, for the first time in current literature, the feasibility of a biohybrid middle ear prosthesis, composed of titanium surrounded by a bone extracellular matrix as bio-coating. We have hereby studied the adhesion and proliferation of human adipose-derived mesenchymal stem cells (hASC) on titanium scaffolds in vitro. Moreover, we identified the osteogenic differentiation of hASC using an immunofluorescence assay to analyze osteoblasts' gene expression profiles (Alp, Runx2, Col1a1, Osx, and Bglap), and we counted the presence of collagen as a marker of hASC's ability to secrete an extracellular matrix. We utilized scanning electron microscopy to evaluate the presence of an extracellular matrix on the scaffolds. Our preliminary data demonstrated the titanium's ability to support human adipose-derived mesenchymal stem cell colonization, proliferation, and osteoblastic differentiation, in order to obtain a biohybrid device. Our experience seems encouraging; thus, we advocate for further in vivo research to corroborate our results regarding bone transplantation.

Extrusion and Dislocation in Titanium Middle Ear Prostheses: A Literature Review.

Titanium middle ear (ME) prostheses are widely used in surgical practice due to their acoustic properties. However, they present a significant drawback shared by all synthetic materials currently in use for ME reconstruction: they can be rejected by the organism of the host. In this study, we aim to review the current literature on titanium partial ossicular replacement prostheses (PORPs) and total ossicular replacement prostheses (TORPs) extrusion and dislocation. Eighty articles were analysed after a full article review based on the inclusion and exclusion criteria. The most common indication for reconstruction was chronic otitis media with cholesteatoma. The average extrusion or dislocation rate was 5.2%, ranging from 0 to 35%. The average improvements in the air-bone gap were 12.1 dB (1.6 dB to 25.1 dB) and 13.8 (-0.5 dB to 22.7 dB) for the PORP and TORP groups, respectively. The data reported on this topic are highly variable, demonstrating that functional outcomes are difficult to predict in clinical practice. We believe that the current limitations could be overcome with technological developments, including bioengineering research focused on promoting prosthesis adaptation to the ME environment.

Nitinol in Medical Devices: Not so Innocuous (P3-5.019)

<h3>Objective:</h3> We report two cases of delayed leukoencephalopathy (DLE) secondary to aneurysmal intracranial stenting and a middle ear prosthesis, both made of a nickel-titanium alloy (nitinol). <h3>Background:</h3> Nitinol is widely used in medical device manufacturing due to its favorable physicochemical properties: shape memory, biocompatibility, superelasticity, and corrosion resistance. <h3>Design/Methods:</h3> Two case reports. <h3>Results:</h3> A 36-year-old woman with a history of ankylosing spondylitis presented with headache and visual distortion. She was found to have an intracranial aneurysm that was repaired with the Neuroform Atlas Stent System. Five weeks later, she acutely developed a fluctuating right sensorimotor deficit. Magnetic resonance imaging (MRI) of the brain showed small regions of T2 hyperintensity with stippled enhancement in the right frontal lobe along the superior frontal sulcus and the white matter of the left parietal and occipital lobes. Another 72-year-old woman with a history of otosclerosis, status post-surgery with eclipse piston prosthesis, presented with right trigeminal neuralgia. A brain MRI showed a right paraclinoid meningioma and three upper cervical cord lesions on sagittal slices. She received radiotherapy with improvement. Seven weeks later, she developed hypersomnolence, vomiting, diplopia, and ataxia. Brain MRI demonstrated an interval appearance of multifocal and bilateral ring-enhancing lesions in the cerebellum, pons, and the right midbrain. Both patients had extensive and unremarkable serum, CSF, vascular and spine imaging, and malignancy workup. A manufacturer review of both devices revealed that they were made of nitinol. <h3>Conclusions:</h3> Titanium and nitinol are less well-known as allergens than nickel. In ionic form, they act as haptens, bonding to native proteins and stimulating the immune system 1) immediately with mastocytes and basophils degranulation (Type I) or 2) in a delayed, type IV cellular hypersensitivity that might present in the brain and spinal cord as a demyelinating disease. We hope to increase clinician awareness of nitinol-induced DLE, which could be easily misdiagnosed. <b>Disclosure:</b> Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bayer. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genentech. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Celgene/BMS. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genzyme. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Merck Serono. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Teva Neurosciences. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for TG Therapeutics. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Teva. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Novartis. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Genentech. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for BMS. The institution of Dr. Zabad has received research support from Adamas. The institution of Dr. Zabad has received research support from Biogen. The institution of Dr. Zabad has received research support from Novartis. The institution of Dr. Zabad has received research support from Sun Pharma. The institution of Dr. Zabad has received research support from Parexel &amp; MedDay Pharmaceuticals. Dr. Solis has nothing to disclose. Dr. Venegas has nothing to disclose. Dr. Dennis has nothing to disclose. Dr. Piccione has nothing to disclose. Dr. Westerhuis has nothing to disclose. Dr. Arcot Jayagopal has nothing to disclose.

Feasibility of 3D-printed middle ear prostheses in partial ossicular chain reconstruction.

Despite advances in prosthesis materials, operating microscopes and surgical techniques during the last 50 years, long-lasting hearing improvement remains a challenge in ossicular chain reconstruction. Failures in the reconstruction are mainly due to inadequate length or shape of the prosthesis, or defects in the surgical procedure. 3D-printed middle ear prosthesis might offer a solution to individualize treatment and obtain better results. The aim of the study was to study the possibilities and limitations of 3D-printed middle ear prostheses. Design of the 3D-printed prosthesis was inspired by a commercial titanium partial ossicular replacement prosthesis. 3D models of different lengths (1.5-3.0 mm) were created with Solidworks 2019-2021 software. The prostheses were 3D-printed with vat photopolymerization using liquid photopolymer Clear V4. Accuracy and reproducibility of 3D printing were evaluated with micro-CT imaging. The acoustical performance of the prostheses was determined in cadaver temporal bones with laser Doppler vibrometry. In this paper, we present an outline of individualized middle ear prosthesis manufacturing. 3D printing accuracy was excellent when comparing dimensions of the 3D-printed prostheses and their 3D models. Reproducibility of 3D printing was good if the diameter of the prosthesis shaft was 0.6 mm. 3D-printed partial ossicular replacement prostheses were easy to manipulate during surgery even though they were a bit stiffer and less flexible than conventional titanium prostheses. Their acoustical performance was similar to that of a commercial titanium partial ossicular replacement prosthesis. It is possible to 3D print functional individualized middle ear prostheses made of liquid photopolymer with good accuracy and reproducibility. These prostheses are currently suitable for otosurgical training. Further research is needed to explore their usability in a clinical setting. In the future, 3D printing of individualized middle ear prostheses may provide better audiological outcomes for patients.

Real-time monitoring of middle ear prosthesis coupling

IntroductionIn reconstructive middle ear surgery, acoustic quality has received a high level of attention in recent years. Careful intraoperative selection and positioning of passive middle ear prostheses during tympanoplasty with ossiculoplasty is essential to ensure satisfactory sound transmission and postoperative hearing outcome. The reconstruction quality of the ossicular chain (OC) can be evaluated intraoperatively using a surgical assistance system which is based on a real-time monitoring system (RTM system) that acquires the transmission (middle ear transfer function (METF)) with electromagnetic excitation of the OC. In this experimental study, the METF with electromagnetic excitation of the (reconstructed) OC was compared to usual acoustic excitation and the benefit of the RTM system was investigated for the implantation of partial (PORP) and total (TORP) prostheses. MethodsLaser Doppler vibrometry (LDV) was used to measure the middle ear transfer function (METF) in 18 human temporal bones (TB). The RTM system uses electromagnetic excitation of the OC with a magnet placed on the umbo. Comparatively, measurements with the usual acoustical excitation, using an earphone in the external auditory canal, were performed. The measurements began with the intact OC, followed by real-time monitoring guided OC reconstruction with PORP and TORP. In addition, during the simulation of an intraoperative setting, the influence of the influence of opening (tympanomeatal flap lifted and pushed anteriorly) and closing (tympanomeatal flap folded back) the tympanic membrane on the measurements with the RTM system was determined. ResultsElectromagnetic and acoustic excitation of the intact and the reconstructed OC provided comparable METF. The application of the RTM system significantly improved the quality of the OC reconstruction. The METF increased by up to 10 dB over the entire frequency range during implantation of the PORP with positioning control by the RTM system. When using the TORP, the METF could be improved by up to 15 dB. The opening of the tympanomeatal flap did not affect the measurements with the RTM system at the reconstructed OC. ConclusionIn this TB study, we demonstrated that the quality of OC reconstruction (improved METF as a benchmark for improved transmission) could be significantly increased by means of a RTM system. Intraoperative studies should now be conducted to investigate to which quantitative extent the intraoperative reconstruction quality can be improved and whether or not this improvement also manifests in an increased (long-term) hearing outcome. This will enable conclusions to be drawn about the contribution of the intraoperative reconstruction quality to the (long-term) hearing outcome in the context of the conglomerate of various factors influencing the postoperative hearing outcome.

3D Printing of Human Ossicle Models for the Biofabrication of Personalized Middle Ear Prostheses

The middle ear bones (‘ossicles’) may become severely damaged due to accidents or to diseases. In these situations, the most common current treatments include replacing them with cadaver-derived ossicles, using a metal (usually titanium) prosthesis, or introducing bridges made of biocompatible ceramics. Neither of these solutions is ideal, due to the difficulty in finding or producing shape-matching replacements. However, the advent of additive manufacturing applications to biomedical problems has created the possibility of 3D-printing anatomically correct, shape- and size-personalized ossicle prostheses. To demonstrate this concept, we generated and printed several models of ossicles, as solid, porous, or soft material structures. These models were first printed with a plottable calcium phosphate/hydroxyapatite paste by extrusion on a solid support or embedded in a Carbopol hydrogel bath, followed by temperature-induced hardening. We then also printed an ossicle model with this ceramic in a porous format, followed by loading and crosslinking an alginate hydrogel within the pores, which was validated by microCT imaging. Finally, ossicle models were printed using alginate as well as a cell-containing nanocellulose-based bioink, within the supporting hydrogel bath. In selected cases, the devised workflow and the printouts were tested for repeatability. In conclusion, we demonstrate that moving beyond simplistic geometric bridges to anatomically realistic constructs is possible by 3D printing with various biocompatible materials and hydrogels, thus opening the way towards the in vitro generation of personalized middle ear prostheses for implantation.

A Partial Ossicular Replacement Prosthesis With a Concentric Ball Joint in the Headplate.

In passive middle ear prosthetics, rigid implants have proven successful in reconstructing the ossicular chain. However, these cannot fully replicate the physiology of the ossicular chain. Pressure fluctuations cause high stresses in rigid passive prostheses, which can result in dislocation, protrusion, and pre-tension in the annular ligament resulting in unsatisfactory hearing results. In collaboration with MED-EL, we developed a new passive middle ear prosthesis that features a balanced, centered ball joint between the headplate and shaft of the prosthesis. We compared the sound transmission properties of this new prosthesis with those of a standard rigid prosthesis. Using Laser-Doppler-Vibrometry, we measured the sound-induced velocity of the stapes footplate relative to a given acoustic stimulus. The new prosthesis showed equivalent sound transmission characteristics compared to the rigid prosthesis, whereas retaining the ability to compensate for pressure fluctuations due to its ball joint. This ensures good transmission properties even during displacements of the tympanic membrane. This development is a further step toward a physiological reconstruction of the ossicular chain. NA Laryngoscope, 133:1717-1721, 2023.

Automated human temporal-bone experiments

Abstract Temporal-bone (TB) experiments are useful for the investigation of middle-ear and inner-ear transfer properties, and the analysis and development of active or passive middleear prostheses or related devices. To acquire the mechanical middle-ear (ME) response, the Laser-Doppler vibrometry (LDV) is utilized as a preferred method. In most setups, the exact measurement point chosen on the biological structure of interest as well as the direction of the corresponding vibration measurement is not precisely defined and of unknown reproducibility. Hence, an automated setup controlling coordinates of TB and measurement direction is developed and tested. To test the reproducibility, TBs were measured with ER7C and ER10C probe microphones employing a small industrial robot to position the TB to the ME points of interest and align it to the laser beam. The position and vibration data acquired at the same locations at different points of time were processed and compared. Measured transfer functions indicate noticeable differences at some frequency ranges. Nonetheless, the reproducibility of positioning to repeatedly measured points proved itself relatively accurate, if no manipulations in the setup are made. In conclusion, the current study shows that automated LDV TB measurement system is in principle capable to adapt to the changes in setup during intermediate preparation steps. With more acquired data, the setup stability and reproducibility can be more precisely verified, and additional improvements can be made.

Biocompatible Materials in Otorhinolaryngology and Their Antibacterial Properties.

For decades, biomaterials have been commonly used in medicine for the replacement of human body tissue, precise drug-delivery systems, or as parts of medical devices that are essential for some treatment methods. Due to rapid progress in the field of new materials, updates on the state of knowledge about biomaterials are frequently needed. This article describes the clinical application of different types of biomaterials in the field of otorhinolaryngology, i.e., head and neck surgery, focusing on their antimicrobial properties. The variety of their applications includes cochlear implants, middle ear prostheses, voice prostheses, materials for osteosynthesis, and nasal packing after nasal/paranasal sinuses surgery. Ceramics, such as as hydroxyapatite, zirconia, or metals and metal alloys, still have applications in the head and neck region. Tissue engineering scaffolds and drug-eluting materials, such as polymers and polymer-based composites, are becoming more common. The restoration of life tissue and the ability to prevent microbial colonization should be taken into consideration when designing the materials to be used for implant production. The authors of this paper have reviewed publications available in PubMed from the last five years about the recent progress in this topic but also establish the state of knowledge of the most common application of biomaterials over the last few decades.

A comparison of sound transmission of middle ear prostheses manufactured via SLM

Middle ear surgeries involve Total Ossicular Replacement Prosthesis (TORP) or Partial Ossicular Replacement Prosthesis, where all or some of the three ossicle bones are replaced. Current prostheses are dissimilar to the natural ossicles in geometry, size and only recover up to 75% sound transmission. Additive manufacturing offers complex, near-net shape geometries that allow for patient specific implants. A novel design is used to manufacture a TORP in Ti6Al4V(ELI) via Additive Manufacturing. The sound transmission level of the of the additively manufactured titanium prosthesis was measured by laser doppler vibrometry and compared to that of a Silver additively manufactured prosthesis. The sound transmission level of the additively manufactured prostheses are also compared to that of the international standards and literature using this method.

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.