Reconstructive Middle Ear Surgery Research Articles

Application of Belfast 15/30dB Rule of Thumb in Assessing Hearing Benefit in Middle Ear Reconstructive Surgery.

The objective of this study is to assess the concordance between Belfast 15/30dB rule of thumb and subjective hearing benefit in middle ear reconstruction surgery. A total of 105 cases of chronic otitis media (COM) (both mucosal and squamosal type) with conductive hearing loss and who underwent middle ear reconstructive surgery during the study period from January 2019 to January 2022 were included. All cases were followed up at 6week and at 3months of postoperative duration for subjective assessment of hearing with questionnaire and pure tone audiometry as per standard of care and correlated with Belfast 15/30dB rule of thumb. Concordance with Belfast rule of thumb was seen in 73.4% cases of both mucosal and squamosal type of COM. Belfast 15/30dB rule of thumb is a valuable and useful tool to predict hearing benefit following middle ear reconstructive surgery, but, it suffers from the disadvantages of all or none phenomenon and it does not grade the level of hearing improvement. The prediction of postoperative subjective hearing with this Belfast rule of thumb is more reliable in mucosal type of COM than in squamosal type of COM.

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.

Personalized prediction of the results of reconstructive surgery for chronic otitis media

Introduction. The goal of the surgical treatment of patients with chronic otitis media is to eliminate the consequences of the inflammatory and destructive disease while preserving the anatomy of the middle ear and improving auditory function. According to the literature, the outcome of middle ear reconstructive surgery for the surgeon and the patient in most cases remains unpredictable. The development of an integrated approach to predicting the results of reconstructive sanitizing surgery will make it possible to select the most effective surgical tactics in terms of treatment time and type of surgical intervention.Aim.To develop a methodology for personalized prediction of the result of operations on the temporal bone in patients with chronic otitis media and substantiate the choice of optimal surgical tactics, taking into account clinical and functional parameters.Materials and methods.A retrospective study was carried out to compare the data of patients with the use of the author’s personalized prognosis method: “A method for predicting the result of tympanoplasty” and “A method for predicting the degree of hearing loss in otosurgery for chronic otitis media” with the results of surgical treatment of 263 patients with chronic otitis media, operated on in hospitals in Moscow. Chelyabinsk in 2018–2020.Results and discussion. In the observation, the patients were divided into two groups according to the sum of points, which determined the volume, type and timing of the operation. The sum of points less than or equal to 20 was assessed as a favorable prognosis for reconstructive debridement surgery. The sum of points in the range from 21–40 was assessed as the possibility of carrying out onestage surgery for the purpose of sanitation and reconstruction, but the patient should be informed about the unfavorable prognosis for the restoration of hearing. A score greater than 40 is assessed as an unfavorable prognosis, with an indication for separate-stage surgery, indicating a socially significant hearing loss in the postoperative period in patients with chronic otitis media.Conclusion. A personalized approach to predicting the results of surgical treatment forms groups of patients with chronic suppurative otitis media and helps in choosing surgical tactics in terms of the type, volume and timing of one-stage or separatestage reconstructive surgery and the need for reoperation for a period of one year.

A contemporary overview on the enigma of managing recalcitrant or intractable post-operative otorrhoea following middle-ear surgery: perspectives, principles and practices.

A common problem in otological surgeries is the persistence of ear discharge in a patient who has undergone middle-ear reconstructive surgery, despite an intact graft. There is a dearth of knowledge in the literature on treatment strategies in such post-operative cases of recalcitrant otorrhoea. This was a retrospective observational descriptive study conducted on 45 patients who fitted the criteria for recalcitrant post-operative otorrhoea. All 45 patients showed no response to conservative treatment for 14 days from onset of discharge. Therefore, these patients were then given antiseptic ear drops. Thirty patients out of 45 showed a good response to antiseptic ear drops and achieved a dry ear at the end of the treatment. In patients with recalcitrant otorrhoea with or without granulations after middle-ear reconstruction surgery, this study found that topical antiseptic ear drops, particularly those using boric acid powder, are more effective than topical antibiotic drops.

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.

Virtual Quality Control in Middle Ear Surgery: Is Image-guided Tympanoscopy a Valuable Tool for Depicting Borderline Situations?

Before modern imaging was introduced, revision surgery was the only way to evaluate possible reasons for inadequate improvement in hearing after ossicular replacement during reconstructive middle ear surgery. The aim of this study was to evaluate freely navigable virtual tympanoscopy using different computed tomographic modalities. We compared cone-beam computed tomography (CBCT), flat panel computed tomography (FPCT), and conventional computed tomography in helical mode (CTH), volume mode (CTV), and ultra high resolution mode (CTD). Four temporal bone specimens were reconstructed with partial or total ossicular replacement prostheses. The best functional results for prosthetic coupling were achieved under the control of laser Doppler vibrometry (LDV). Afterward, a progressive step-by-step decoupling of the prostheses was carried out. Different prosthesis positions were evaluated by LDV as well as different computed tomographic modalities with 3D reconstruction of each dataset. Anatomical structures were better depicted and the best position and coupling of inserted prostheses were achieved using CBCT. All imaging techniques could be used to control the position of middle ear prostheses, but CBCT provided the highest resolution and the best image quality in both 2D and 3D reformations and in 3D-animated video representation. Compared with several other imaging modalities, CBCT was best at depicting miscellaneous coupling problems. Noninvasive detection of coupling problems caused by minimal loss of contact between prostheses and middle ear ossicles will influence the clinical outcome. This early detection will help to determine whether revision surgery is needed.

Qualität in der Mittelohrchirurgie – eine kritische Standortbestimmung

When evaluating the outcome of reconstructive middle ear surgery, it is insufficient to use only the achieved improvement of audiometric measurement results. Although, as functional parameters, they occupy a central position in the therapeutic assessment of the ear as a sensory organ, they must be supplemented by a number of modern quality control factors. Different perspectives for assessment of quality must be taken into account. What is important from the patient's point of view may not be the same factors as to the physician, while the physician places a high value on factors that are less significant for the medical insurance company. The international otological community, who would like to draw conclusions from middle ear surgery data, might set different criteria altogether for assessing quality of surgery.Hence, we propose to adapt the general concept of quality to middle ear surgery. This must be implemented on different levels and surgical therapy of middle ear diseases must be understood as a process.This means that quality assessment must comprise additional aspects, which include a structured description and recording of disease-specific symptoms, findings, and outcome of treatment. Furthermore, in today's world the use of internationally recognized classification systems must be regarded as a quality feature, in order to make results not only publishable but also capable of meta-analysis. Internationally developed and recognized reporting systems are available for this purpose. Their use in routine care not only makes the collected data internationally comparable, but also enables systematic evaluation within the institution for quality description and control.In addition to audiological measurement results, surgical quality indicators are considered. We also focus on emerging complications and the value of systematic and structured evaluation and documentation systems. Validated measuring instruments are already available for patient benefit assessment, the use of which should no longer be limited to scientific studies. In summary, quality assessment of surgery should be extended to include not only the "patient as a whole", but also to the "therapy process as a whole", incorporating features of structural and process quality.

Results of Tragal Perchondrium and Cartilage in Middle Ear Reconstructive Surgery

Results of Tragal Perchondrium and Cartilage in Middle Ear Reconstructive Surgery

Tympanoplasty - news and new perspectives.

Techniques and biomaterials for reconstructive middle ear surgery are continuously and steadily developing. At the same time, clinical post-surgery results are evaluated to determine success or failure of the therapy. Routine quality assessment and assurance is of growing importance in the medical field, and therefore also in middle ear surgery. The exact definition and acquisition of outcome parameters is essential for both a comprehensive and detailed quality assurance. These parameters are not the audiological results alone, but also additional individual parameters, which influence the postoperative outcome after tympanoplasty. Selection of patients and the preoperative clinical situation, the extent of the ossicular chain destruction, the chosen reconstruction technique and material, the audiometric frequency selection and the observational interval are only some of them. If these parameters are not well documented, the value of comparative analyses between different studies is very limited. The present overview aims at describing, comparing, and evaluating some of the existing assessment and scoring systems for middle ear surgery. Additionally, new methods for an intraoperative quality assessment in ossiculoplasty and the postoperative evaluation of suboptimal hearing results with imaging techniques are available. In the area of implant development, functional elements were integrated in prostheses to enable not only good sound transmission but also compensation of occurring atmospheric pressure changes. In combination with other components for ossicular repair, they can be used in a modular manner, which so far show experimentally and clinically promising results.

To Evaluate and Compare the Result of Ossiculoplasty Using Different Types of Graft Materials and Prosthesis in Cases of Ossicular Discontinuity in Chronic Suppurative Otitis Media Cases.

Chronic suppurative otitis media, with and without cholesteatoma, frequently results in disruption of the ossicular chain. The present study was designed to compare the outcome using autologous ossicle and titanium prosthesis in two groups of suitable patients presenting with chronic suppurative otitis media for middle ear reconstructive surgeries. A prospective study done from July 2012 to December 2013, at Mahatma Gandhi Medical College and Hospital, Sitapura, Jaipur (Rajasthan). The target group included patients with chronic suppurative otitis media admitted and planned for reconstructive middle ear surgery. The study group patients among the target group requiring certain ossicular reconstruction. The patients included were patients with CSOM with or without cholesteatoma in which there was ossicular discontinuity. The patients were divided in two groups A and B. In group A patients autologous incus was used and in group B titanium prosthesis either TORP or PORP was used for ossicular replacement. Out of 340 patients as target group, 88 patients were included in study group. Further 88 patients of study group, 51 patients were included in group A; rest 37 patients were included in group B. In group B patients partial ossicular replacement platinum prosthesis was used in 31 patients while in rest 6 patients a total ossicular replacement prosthesis was used. Out of 88 patients, 79 were primary cases and 9 were revision cases. Pre and post operative air bone gap were noted. Pre operatively both of the groups were identical in relation to air-bone gap. The postoperative air-bone gap was calculated as the difference between postoperative air conduction and preoperative bone conduction. On comparison of preoperative and post-operative hearing results there was improvement in air conduction threshold and air bone gap in both the groups. Post operatively difference in air bone gap closure between group A and group B was found statistically significant (P value=0.032) suggesting better hearing outcomes after using titanium ossicular replacement prosthesis. On comparing partial or total ossicular replacement prosthesis no significant difference was found for the audiological outcome (P=0.434). Various prognostic factors were also noted for air bone gap closure. Titanium ossicular replacement prosthesis have better outcome, and no significant difference found in audiological outcome for TORP and PORP.

Tympanoplasty - News And New Perspectives

Techniques and biomaterials for reconstructive middle ear surgery are under steady, ongoing development. At the same time, clinical post-surgery results are evaluated to determine success or failure of the therapy. Routine quality assessment and assurance is of growing importance in the medical field, and therefore also in middle ear surgery. The exact definition and acquisition of outcome parameters is essential for both a comprehensive and detailed quality assurance. These parameters are not the audiological results alone, but also additional individual parameters which influence the postoperative outcome after tympanoplasty. Selection of patients and the preoperative clinical situation, the extent of the ossicular chain destruction, the chosen reconstruction technique and material, the audiometric frequency selection and the observational interval are only some of them. If these parameters are not well documented comparative analyses between different studies are of limited value. The present overview aims to describe, compare and evaluate some of the existing assessment and scoring systems for middle ear surgery. Additionally, new methods for an intraoperative quality assessment in ossiculoplasty and the postoperative evaluation of suboptimal hearing results with imaging techniques are available. In the area of implant development functional elements were integrated in prostheses to enable not only good sound transmission but also compensation of occurring atmospheric pressure changes. In combination with other components for ossicular repair they can be used in a modular manner which, so far show experimentally and clinically promising results.

Tympanometric assessment of Eustachian tube function as a prognostic indicator in myringoplasty

Aim To determine eustachian tube function in tubo-tympanic type of chronic ear disease and correlate it with pathological changes in middle ear. Objective To ascertain whether eustachian tube function had any demeanor upon the outcome of myringoplasty. Backgound The prevailing interest in the patho-physiology of the eustachian tube has been stimulated by the persistent incidence of middle ear effusion and chronic otitis media. The ongoing sophistication in current middle ear reconstructive surgery has added more dimensions to the study of eustachian tube and its effects in the course of reconstructive middle ear surgery. One of the prime elements accountable for failure of reconstructive middle ear surgery has been tubal dysfunction. Method In the present study eustachian tube function was evaluated in in 30 patients who were undergoing myringoplasty for tubo-tympanic type of chronic suppurative otitis media having central perforation by tuning fork tests, microscopic evaluation of the middle ear mucosa and Impedance audiometry. Results 70% of the myringoplasty cases had good surgical outcome and of the 24 cases that had good eustation tube function 87.5% had successful surgical outcome remaining cases had recurrence of otorrhea. Conclusion The results were validating good eustachain tube function as a criterion for electing cases under middle ear reconstructive surgery and Impedance audiometer assures a superlative means of appraising Eustachain tube function.

A New Intraoperative Real-time Monitoring System for Reconstructive Middle Ear Surgery: An Experimental and Clinical Feasibility Study.

Electromagnetical excitation of ossicular vibration is suitable for middle ear transmission measurements in the experimental and clinical setting. Thereby, it can be used as a real-time monitoring system for quality control in ossiculoplasty. Positioning and coupling of middle ear prosthesis are a precondition for good postoperative hearing results, but at the same time completely dependent upon the surgeon's subjective judgment during surgery. We evaluated an electromagnetically driven measurement system that enables for in vitro and in vivo transmission measurements and thus can be used as a real-time monitoring tool in ossicular reconstruction. For electromagnetical excitation a magnet was placed on the umbo of the malleus handle and driven by a magnetic field. The induced stapes displacement was picked up by laser Doppler vibrometry on the footplate. Measurements were performed on the intact ossicular chain in five cadaveric temporal bones and during five cochlear implant surgeries. Additionally, two ossiculoplasties were performed under real-time transmission feedback with the monitoring system. Experimentally, the equivalent sound pressure level of the electromagnetic excitation was about 70 to 80 dB which is 10 to 20 dB less than the acoustic stimulation. In the intraoperative setup the generated stapes displacements were about 5 to 20 dB smaller compared with the temporal bone experiments. Applied as real-time feedback system, an improvement in the middle ear transfer function of 4.5 dB in total and 20 dB in partial ossicular reconstruction were achieved. The electromagnetical excitation and measurement system is comparable to the gold standard with acoustical stimulation in both, the experimental setup in temporal bones as well as in vivo. The technical feasibility of the electromagnetical excitation method has been proven and it is shown that it can be used as a real-time monitoring system for ossiculoplasty in the operation room.

Clinical investigation of flat panel CT following middle ear reconstruction: a study of 107 patients

After middle ear reconstruction using partial or total ossicular replacement prostheses (PORP/TORP), an air-bone gap (ABG) may persist because of prosthesis displacement or malposition. So far, CT of the temporal bone has played the main role in the diagnosis of reasons for postoperative insufficient ABG improvement. Recent experimental and clinical studies have evaluated flat panel CT (fpCT) as an alternative imaging technique that provides images with high isovolumetric resolution, fewer metal-induced artefacts and lower irradiation doses. One hundred and seven consecutive patients with chronic otitis media with or without cholesteatoma underwent reconstruction by PORP (n = 52) or TORP (n = 55). All subjects underwent preoperative and postoperative audiometric testing and postoperative fpCT. Statistical evaluation of all 107 patients as well as the sole sub-assembly groups (PORP or TORP) showed a highly significant correlation between hearing improvement and fpCT-determined prosthesis position. FpCT enables detailed postoperative information on patients with middle ear reconstruction. FpCT is a new imaging technique that provides immediate feedback on surgical results after reconstructive middle ear surgery. Specific parameters evaluated by fpCT may serve as a predictive tool for estimated postoperative hearing improvement. Therefore this imaging technique is suitable for postoperative quality control in reconstructive middle ear surgery. • Flat panel CT offers advantages with regard to artefacts and radiation dose. • FpCT provides higher isovolumetric resolution of temporal bone and middle ear implants. • FpCT allows prediction of the postoperative hearing outcome in patients. • FpCT is an important tool for immediate postoperative quality control. • FpCT improves postoperative management of patients with complications following ossicular replacement.

Tympanometry, a Prognostic Indicator of Myringoplasty with Assessment of Eustachian Tube Function

Objective: To determine Eustachian tube function in tubotympanic type of chronic ear disease and to correlate Eustachian tube function with pathological change in middle ear mucosa. Materials and Methods: A prospective study of the cases of tubotympanic type of chronic suppurative otitis media was undertaken. Patients were subjected to clinical examination followed by audiometry tests and impedence audiometry to determine eustachian tube functions. Patients were then subjected to myringoplasty and eustachian tube function were then reassessed post operatively. Results: In our study, out of 30 cases who underwent myringoplasty, 21 cases had successful surgical outcome and 9 cases were failed. Out of 24 cases of good Eustachian tube function, 21 cases had successful surgical outcome intends of taking up graft, absence of otorrhea and improvement in hearing. In remaining 3 cases, there was recurrence of otorrhea with central perforation. All the 6 cases with poor Eustachian tube function had surgical failure. Conclusion: The prognosis of the middle ear reconstructive surgery has direct correlation with Eustachian tube functions and Eustachian tube function tests should be a routine investigation in all the cases planned for surgical reconstruction of the middle ear.

Influence of Surface Processing on the Biocompatibility of Titanium.

Surface conditioning of titanium middle ear implants results in an improved biocompatibility, which can be characterized by the properties of fibroblasts cultured on conditioned surfaces. Titanium has been established as a favorable biomaterial in ossicular chain reconstruction. The epithelization of the surface of the implants is important for their integration and stable positioning in the middle ear. Mouse fibroblast cells were cultured on platelets made from pure Grade 2 titanium. Platelets that had been etched along their production process were compared to unetched platelets. The DNA in the cell nuclei was stained with DAPI and the actin filaments of the cytoskeleton were stained with FITC-conjugated phalloidin in order to analyze the cells grown on etched and unetched platelets by fluorescence microscopy. SEM (scanning electron microscopic) images were used to compare the surface structure of etched and unetched titanium platelets. There was a statistically significant increase of the area covered by the cytoplasm and increased actin expression by fibroblasts grown on the etched titanium platelets. In addition, the area of the platelets covered by nuclei on the etched platelets exceeded on average the one on unetched platelets, although this difference was not significant. The SEM pictures comparing unetched and etched titanium platelets showed a clear difference in surface structure. Surface conditioning of titanium implants improved the epithelization by fibroblasts and consequently etched titanium should be the preferred biomaterial for reconstructive middle ear surgery.

A study on the relevance of preoperative assessment of Eustachian tube function in myringoplasty

Aim : Pathophysiology of Eustachian tube significantly affects the result of middle ear reconstructive surgery. The aim of this study is to ascertain the relevance of preoperative assessment of tubal function on the results of myringoplasty and to correlate the outcome of surgery with the tubal function gradings. Materials and Methods : A total of 58 cases of dry central perforation of tympanic membrane were divided into two groups. In control group A, pre-operative Eustachian tube function was not checked. In Test group B, pre-operative Eustachian tube function was checked by modified inflation-deflation test using impedance audiometer. Results : Success was assessed at 4th month postoperatively on the basis of intact drum. The results between both groups were compared using Chi-square test. There was no statistically significant difference (P< 0.05) between the control and the test group. Conclusion : The capability to reduce an applied negative pressure correlates well with the successful result of a tympanic membrane graft. However, failure to equilibrate negative pressure does not discriminate between success and failure of this operative procedure.

Osseointegration of Titanium Prostheses on the Stapes Footplate

The success of middle ear reconstructive surgery depends on stable coupling between the prosthesis and residual ossicles. To establish a stable fixed point on the stapes footplate for subsequent prosthesis reconstruction, a titanium footplate anchor was coated with osteoinductive substances to induce a controlled osseointegration on the footplate. Various studies have shown that collagen-based matrices with and without bone growth and differentiation factors can induce and enhance bone formation and consequently increase implant stability. The ears of 23 one-year-old Merino sheep (n = 46) were divided into five groups and implanted with a specially designed footplate anchor. The surface of each implant was modified by applying a collagenous matrix (collagen I or II) either with immobilized bone morphogenic protein (BMP-4) or transforming growth factor-ss, respectively, to stimulate osteoblastic activation and differentiation on the stapes footplate with subsequent osseointegration. Polychrome labeling was used to assess new bone formation and remodeling during the study. After study termination on day 84, synchrotron radiation-based computed microtomography and histomorphometry were used to identify bone implant contact. Eight implants showed radiographical and/or histological evidence of integration by newly formed bone. An osseointegration could histologically be proven in two of these eight specimens, and additional ectopic bone formations were seen in another 21 specimens. In all animals, bone turnover on the footplate was proven by polychrome labeling. This study proves the general ability to induce a controlled osseointegration of titanium implants biologically activated with artificial extracellular matrices on their surfaces on the stapes footplate in a mammalian organism.

Optische Kohärenztomographie in der Mittelohrchirurgie

The application of optical coherence tomography (OCT) in middle ear surgery has a high diagnostic potential, especially for intraoperative evaluation of the cause of stapes fixation, intraoperative assessment of the morphology of the stapes footplate in revision stapes surgery, and as an orientation guide in cochlear implantation in congenital anomalies. OCT displays the middle and inner ear structures precisely. This technology enables the surgeon to use this information for further specification of the intraoperative modus operandi. Considering our own in vivo and ex vivo investigations and animal experiments, potential areas of application can be defined: visualization of the oval window niche in revision stapesplasty and reconstructive middle ear surgery, as well as during explorative tympanotomy for intraoperative assessment of perilymph fistula, and demonstration of structures of the exposed but not opened inner ear.

Biocompatibility of Polylactides in the Middle Ear

To study the suitability of resorbable polylactides for reconstruction in middle ear surgery. Twenty-four chinchillas. Twenty chinchillas were operated on using 2 types of polylactides inserted into the middle ear and outer ear canal, 10 animals in each group. At 6 months, the animals were killed, and their temporal bones were removed for sectioning. Degree of inflammation, fibrosis, degradation of polylactide material, and new bone formation were assessed histologically. Polylactide implants caused only a mild local inflammation, with no difference between the 2 materials tested. Polylactide acid-based middle ear implants were successfully used in the reconstructive middle ear surgery. Resorption occurred without complications.