Malleus-to-Footplate versus Malleus-to-Stapes-Head Ossicular Reconstruction Prostheses: Temporal Bone Pressure Gain Measurements and Clinical Audiological Data

Analysis of the effect of reconstructing the ossicular chain under otoendoscopy with and without a stapes superstructure

BACKGROUND

Numerous studies have been conducted on the effect of the stapes superstructure after ossicular chain reconstruction, but the findings are not uniform.

OBJECTIVE

To compare the hearing outcomes of ossicular chain reconstruction with partial ossicular replacement prosthesis (PORP) or total ossicular replacement prosthesis (TORP) under otoendoscopy.

MATERIALS AND METHODS

The records of 111 patients diagnosed with chronic suppurative otitis media were retrospectively analyzed. These patients were divided into PORP group (n = 57) and TORP group (n = 54). They were further subdivided into subgroups PORP-a (with a malleus handle) and PORP-b (without a malleus handle), subgroups TORP-a and TORP-b. Pre- and postoperative audiometric results were analyzed.

RESULTS

The mean postoperative air conduction hearing thresholds improvement, mean air-bone gap improvement, and the success rate of reconstruction were significantly higher in the PORP group than in the TORP group (p < .05). The mean postoperative air conduction hearing thresholds improvement and the success rate of reconstruction were significantly higher in the PORP-a group than in the TORP-a group (p < .05); and similar results were concluded in comparison of the PORP-b group and the TORP-b group.

CONCLUSIONS AND SIGNIFICANCE

The stapes superstructure has an important positive effect on the postoperative outcome of endoscopic ossicular chain reconstruction.

Real-time monitoring of middle ear prosthesis coupling

INTRODUCTION

In 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.

METHODS

Laser 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.

RESULTS

Electromagnetic 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.

CONCLUSION

In 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.

Effects of preloads on middle-ear transfer function and acoustic reflex in ossiculoplasty with PORP

INTRODUCTION

Surgical outcomes in ossiculoplasty with partial ossicular replacement prostheses (PORPs) are greatly influenced by the amount of preload imposed on the PORP. In this study, the attenuation of the middle-ear transfer function (METF) was experimentally investigated for prosthesis-related preloads in different directions, with and without concurrent application of stapedial muscle tension. Different PORP designs were assessed to determine functional benefits of specific design features under preload conditions.

METHODS

The experiments were performed on fresh-frozen human cadaveric temporal bones. The effect of preloads along different directions were experimentally assessed by simulating anatomical variance and postoperative position changes in a controlled setup. The assessments were performed for three different PORP designs featuring either a fixed shaft or ball joint and a Bell-type or Clip-interface. Further, the combined effect of the preloads towards the medial direction with tensional forces of the stapedial muscle was assessed. The METF was obtained via laser-Doppler vibrometry for each measurement condition.

RESULTS

The preloads as well as the stapedial muscle tension primarily attenuated the METF between 0.5 and 4 kHz. The largest attenuations resulted from the preload towards the medial direction. The attenuation of the METF with stapedial muscle tension was reduced with concurrent PORP preloads. PORPs with a ball joint resulted in reduced attenuation only for preloads along the long axis of the stapes footplate. In contrast to the clip interface, the Bell-type interface was prone to lose coupling with the stapes head for preloads in the medial direction.

CONCLUSIONS

The experimental study of the preload effects indicates a direction-dependent attenuation of the METF, with the most pronounced effects resulting from preloads towards the medial direction. Based on the obtained results, the ball joint offers tolerance for angular positioning while the clip interface prevents PORP dislocations for preloads in lateral direction. At high preloads, the attenuation of the METF with stapedial muscle tension is reduced, which should be considered for the interpretation of postoperative acoustic reflex tests.

Comparison of partial vs. total ossicular chain reconstruction using titanium prosthesis: a retrospective cohort study

PURPOSE

Comparison of the hearing outcomes of titanium partial ossicular replacement prosthesis (PORP) vs. titanium total ossicular replacement prosthesis (TORP) with footplate shoe (Omega Connector) in second stage ossicular chain reconstruction surgeries.

METHODS

In this retrospective cohort study in a tertiary hospital, we compared the hearing outcomes in 248 patients who had undergone ossicular chain reconstruction with titanium prostheses PORP (n = 115) vs. TORP (n = 133) from August 2017 to June 2021. Pre-and post-operative audiometric data were assessed.

RESULTS

In general, we found that there were no significant differences between PORP and TORP groups in gains of BC (P = 0.080), AC (P = 0.454), ABG (P = 0.928), SRT (P = 0.065), and SDS (P = 0.363). There were no significant differences in terms of ABG gain between the two groups. Regarding ABG gains frequency-specific analysis in the ears with pre-operative conductive hearing loss, there were no significant differences between low-frequencies (P = 0.260) and high-frequencies (P = 0.973) between the two groups.

CONCLUSION

To sum up, this research provided additional evidence with respect to hearing outcomes after staged ossicular chain reconstruction with PORP and TORP. The practical application of our study is that TORP with footplate shoe (Omega Connector) is comparable with PORP in staged ossiculoplasty.

Comparison of Titanium versus Polycel as Partial Ossicular Replacement Prosthesis: A Randomized Clinical Trial

INTRODUCTION

Each type of prosthesis for ossiculoplasty has its advantages and disadvantages, and the choice of the best material has been a matter of various studies. The present study aimed to make a comparison between the hearing outcomes of partial ossicular replacement prosthesis (PORP) using titanium versus Polycel prosthesis.

MATERIAL AND METHODS

A total of 106 patients undergoing PORP as a second stage ossiculoplasty were analyzed in this study. Following that, they were randomly assigned to two groups of titanium (n=54) and Polycel (n=52) prosthesis. Subsequently, pre-and post-operative audiometric data were assessed based on the aim of the study.

RESULTS

In general, the post-operative air-bone gap within 20 dB was given to 63.5% and 55.6% of all ears in the Polycel and titanium groups, respectively, indicating a non-significant difference (P=0.407). Finally, no SNHL was observed in the groups.

CONCLUSION

Overall, the hearing outcomes and the success rate of PORP are comparable between titanium and Polycel prostheses. Therefore, the selection of these prostheses could be based on the surgeons' preferences, availability, and cost.

TORP ossiculoplasty in the presence of an intact stapes superstructure

INTRODUCTION

In this series, we describe ossicular reconstruction using routine TORP in the presence of the stapes superstructure using a tympanic-membrane-to-footplate configuration.

MATERIALS AND METHODS

This is a case series of 12 patients who underwent TORP ossiculoplasties from 1st January 2010 to 31st October 2017. Data collected included demographics, indication for surgery, status of the middle ear and pre-operative and post-operative audiometric data (including pure tone average (PTA) and air-bone gap (ABG)).

RESULTS

The mean pre-operative PTA was 56.5 dB and ABG was 39.8 dB. Surgical success (ABG ≤ 20 dB) was achieved in 83.3%, with an average improvement in PTA of 24.3 dB and closure of ABG of 27.1 dB. The mean post-operative ABG was 12.7 dB.

CONCLUSION

TORP ossiculoplasty with tympanic-membrane-to-footplate configuration is a feasible means of ossicular reconstruction, independent of the status or spatial arrangement of the remnant ossicles. Using this technique, it is possible to achieve a consistently good outcome for improvement in hearing and closure of ABG.

Chronic Otitis Media with Granulation Is a Poor Prognostic Factor for Hearing Improvement and Development of Intracranial Complications

OBJECTIVES

Different types of chronic otitis media are distinguished based on the observed lesions in the middle ear mucous. Hearing improvement is a measurable effect of the surgical treatment of patients with chronic otitis media. Chronic cholesteatoma otitis media and chronic otitis media with inflammatory granulation have a tendency to damage the bone tissue, leading to the development of intratemporal and intracranial complications.

MATERIALS AND METHODS

A prospective analysis of patients who underwent surgery for the first time due to chronic otitis media from 2009 to 2012 was performed. Patients were divided into groups according to the abnormalities of the middle ear mucous observed during otosurgery. Special attention was given to patients diagnosed with chronic otitis media with inflammatory granulation and chronic cholesteatoma otitis media, which are characterized by a tendency to damage the bone tissue.

RESULTS

A total of 293 individuals met the criteria for inclusion in the study. The analysis showed that chronic otitis media with inflammatory granulation had an unfavorable effect on hearing improvement prognosticated postoperatively. Defects in the middle cranial fossa were observed to occur five times more often than defects in the posterior cranial fossa. These defects were usually observed with granulation tissue and rarely with the concurrence of cholesteatoma and granulation tissue.

CONCLUSION

The presence of granulation tissue is an unfavorable prognostic factor for improvement in air and bone conduction. The probability of exposing the dura mater of the brain is higher in cases with granulation tissue than in cases with cholesteatoma.

Pediatric ossiculoplasty: optimizing outcomes

PURPOSE OF REVIEW

Despite years of research, pediatric ossiculoplasty remains a challenging surgery with numerous variables factoring into successful outcomes. The aim of this review is to summarize recent publications on surgical technique, timing, and reconstruction materials.

RECENT FINDINGS

The cause behind ossicular discontinuity does not seem to play a role in hearing results after ossiculoplasty; however, revision surgery is associated with worsening outcomes. The status of the ossicles remains an active area of interest, but the data remain mixed in terms of them playing a role in predicting outcomes in adults and pediatric patients. There remains debate regarding the utility of staging the reconstruction and is often undertaken on a case-by-case basis. Other recent publications highlight positive outcomes associated with canal wall-up procedures, titanium prostheses, and partial ossicular reconstruction prostheses. Endoscopic middle ear surgery in ossiculoplasty has been shown to be successful in monitoring and removal of disease and helpful in reconstruction.

SUMMARY

Pediatric ossiculoplasty remains a challenging yet rewarding procedure. The bulk of publications are retrospective making much of the literature difficult to interpret. There remains a need for prospective and well controlled studies in both adult and pediatric populations.

Manubrio-incudo-stapedioplasty for reconstruction of Austin-Kartush type B ossicular defects

OBJECTIVE

Manubrio-incudo-stapedioplasty functional outcomes were compared to those of other methods for reconstructing Austin-Kartush type B ossicular defects.

METHODS

Forty-two patients underwent Austin-Kartush type B ossicular defect reconstruction using: manubrio-incudo-stapedioplasty (13 patients), an autologous incus (19 patients) or a titanium ossicular replacement prosthesis (10 patients). For manubrio-incudo-stapedioplasty reconstruction, the malleus head was removed, the manubrium was relocated posteriorly and the incus short process was placed on the mobile footplate. The manubrium was placed on the incus body groove and bone cement was applied to stabilise the manubrium-incus junction. Pre- and post-operative hearing thresholds were assessed.

RESULTS

The air-bone gap decreased from 25.9 ± 6.0 dB to 12.3 ± 5.0 dB (p &lt; 0.05) in the manubrio-incudo-stapedioplasty group. The hearing gain was 13.6 ± 5.2 dB for manubrio-incudo-stapedioplasty, 3.4 ± 14.2 dB with the autologous incus, and 3.3 ± 11.07 dB with the titanium ossicular replacement prosthesis. Hearing improvement was greater for manubrio-incudo-stapedioplasty compared to the other reconstruction methods (p &lt; 0.05).

CONCLUSION

Manubrio-incudo-stapedioplasty resulted in satisfactory hearing outcomes in patients with Austin-Kartush type B ossicular defects. This technique can be considered a stable, inexpensive and effective method to reconstruct Austin-Kartush type B ossicular defects.

The significance of selected prognostic factors in pediatric tympanoplasty

OBJECTIVES

The aim of this study was to determine the importance of selected prognostic factors on outcomes of tympanoplasty in children.

MATERIALS AND METHODS

241 children classified into three age groups (3-7, 8-12 and 13-18), had undergone tympanoplasty between 2001 and 2007 and were subsequently observed for at least 2 years. Prognostic factors were assessed with regard to their impact on the functional and anatomical outcome of the tympanoplasty defined, respectively, as postoperative air-bone gap and state of the middle ear.

RESULTS

In 85% of children, a tympanic membrane reconstruction was performed. An unchanged TM was achieved in 85% of the patients in early results and in 76% in later results. Air-bone gap closure was observed in 66% of cases. The earlier preventive retraction pocket tympanoplasty was performed, the better anatomical results were obtained-ranging from 91% in the 3-7 age group versus 75-70% in 8-12 and 13-18 age groups. The results of total or subtotal perforation reconstructions were worse than for small perforation with closure rates of 76.5% vs 94.5%, respectively.

CONCLUSION

Age is not a factor determining the success rate in pediatric tympanoplasty. A better surgical outcome can be achieved in children with a dry ear, and better middle ear condition, because of previously performed surgeries. Preventive tympanoplasty is also advantageous. The hearing results in type 2 and 3 tympanoplasty are similar, but type 1 tympanoplasty has superior efficacy to the former two types.

Experimental Simulation of Clinical Borderline Situations in Temporal Bone Specimens After Ossiculoplasty

OBJECTIVES

One reason for insufficient hearing improvement with a distinct air-bone gap after ossiculoplasty with implantation of partial or total ossicular replacement prostheses can be the dislocation or minimal shifting of the prosthesis. The aim of this study was the simulation of common clinical borderline situations with minimal shifting of the prosthesis in temporal bone specimens after ossiculoplasty. It was furthermore the goal to identify these specific situations through imaging by cone beam computed tomography (cbCT) and direct visual inspection using the operation microscope. Additionally, the functional status was evaluated using laser-Doppler vibrometry (LDV).

DESIGN

We used a total of four temporal bone specimens for this study. A reconstruction with a partial ossicular replacement prostheses was performed in three specimens and with a total ossicular replacement prostheses in one specimen, with good initial acoustic properties. Subsequently, one specific type of prosthesis failure was simulated in each specimen, respectively, by minimally shifting, tilting, or bending the prostheses from their initial positions. These changes were introduced step-by-step until a borderline situation just short of complete acoustic decoupling was reached. Each step was examined using both LDV and cbCT and observed through the operation microscope.

RESULTS

LDV was able to quantify the mechanic function of the ossicular chain after most of the manipulation steps by demonstrating the effect of any shifting of the prosthesis on the middle ear transfer function. However, in some situations, the middle ear transfer function was better with a visually more advanced failure of the prosthesis. In addition, cbCT showed most of the steps with excellent resolution and was able to delineate changes in soft tissue (e.g., cartilage covering).

CONCLUSION

cbCT seems to be a promising imaging technique for middle ear problems. As cbCT and LDV exhibited slightly different advantages and disadvantages regarding the demonstration of borderline situations, the combination of both techniques allowed for a more precise evaluation of middle ear reconstructions. Knowledge of the specific characteristics of these methods and their possible combination might help otologists and otosurgeons to refine indications for revision surgery and improve their personal patient counseling.

First results of a novel adjustable-length ossicular reconstruction prosthesis in temporal bones

OBJECTIVES/HYPOTHESIS

The performance of an ossicular replacement prosthesis (ORP) is influenced by its alignment and appropriate tension between the tympanic membrane and the stapes footplate. A novel ORP with a flexible element that potentially allows for length adjustment in situ is presented and tested for acoustic performance.

STUDY DESIGN

Laser Doppler vibrometry in fresh human cadaveric temporal bones was used to test the acoustic performance of the adjustable ORP relative to standard prostheses used for ossiculoplasty.

METHODS

The three-dimensional (3D) velocity of the stapes posterior crus was measured in the 0.2- to 20-kHz range using a Polytec CLV-3D laser Doppler vibrometer. The middle ear cavity was accessed through a facial recess approach. After measuring the normal response, the incus was removed and stapes velocity was measured in the disarticulated case, then after insertion of the new prosthesis, a conventional prosthesis (Kurz BELL Dusseldorf type), and a sculpted autologous incus prosthesis in each temporal bone. The 3D stapes velocity transfer function (SVTF) was calculated for each case and compared.

RESULTS

The novel ORP design restored stapes velocity to within 6 dB (on average) of the intact response. No significant differences in 3D-SVTF were found between the new, conventional, or autologous ORPs.

CONCLUSIONS

The inclusion of an in situ adjustable element into the ORP design did not adversely affect its acoustic performance. The adjustable element may increase the ease of achieving optimal ORP placement, especially through a facial recess approach.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:2559-2564, 2016.

Determinants of Change in Air-Bone Gap and Bone Conduction in Patients Operated on for Chronic Otitis Media

Background

Middle ear surgery aims to eliminate pathology from the middle ear, improve drainage and ventilation of the postoperative cavity, and reconstruct the tympanic membrane and ossicles.

The aim of this work is to define the factors that affect ABG (air-bone gap) and bone conduction in the patients operated on due to chronic otitis media.

Material/Methods

A prospective analysis of patients operated on due to diseases of the middle ear during 2009–2012 was carried out. The cases of patients operated on for the first time due to chronic otitis media were analyzed.

The analysis encompassed patients who had undergone middle ear surgery. The patients were divided into several groups taking into account the abnormalities of the middle ear mucous and damage of the ossicular chain observed during otosurgery.

Results

A significant hearing improvement was observed in patients with type 2 tympanoplasty in the course of chronic cholesteatoma otitis media and in patients with simple chronic inflammatory process in whom a PORP was used in the reconstruction. Granulation tissue was an unfavorable factor of hearing improvement following tympanoplasty.

A significant improvement of bone conduction was observed in the patients with dry perforation without other lesions in the middle ear.

The elimination of granulation lesions was a positive factor for the future improvement of the function of the inner ear.

Conclusions

The presence of granuloma-related lesions in the middle ear spaces is likely to impede hearing improvement.

Damage to the ossicular chain rules out the possibility of bone conduction improvement after surgery.

The prognosis on tube-related simple chronic otitis media after myringoplasty, with the preserved continuity of the ossicular chain, consists of closing the ABG and leads to significant improvement of bone conduction.

Air-bone gap in ears with a well-repaired tympanic membrane after Type III and Type IV tympanoplasty

OBJECTIVE

To investigate the air-bone conduction hearing gap (A-B gap) after Type III and Type IV stapes columella tympanoplasty in ears with mobile stapes and a well repaired tympanic membrane (TM).

METHODS

Those patients who underwent tympanoplasty in our hospital between 2003 and 2009 and satisfied the following criteria were eligible: (1) good stapes mobility, confirmed intraoperatively; (2) postoperative TM and/or computed tomography (CT) findings that showed a well-aerated tympanic cavity without TM perforation, otorrhea, or middle ear effusion; and (3) measurable air and bone conduction hearing thresholds 1 year postoperatively at all test frequencies (250 Hz, 500 Hz, 1 kHz, 2 kHz, and 4 kHz).

RESULTS

Hearing results were better after Type III tympanoplasty than after Type IV tympanoplasty. After Type III (n=70) and Type IV (n=24) tympanoplasty, the respective mean A-B gaps were 16.4 ± 7.2 dB and 20.1 ± 5.6 dB, respectively. The mean A-B gap was significantly smaller after Type III tympanoplasty than after Type IV tympanoplasty (p<0.05). Regardless of the type of tympanoplasty, the postoperative A-B gap was greatest at 4 kHz.

CONCLUSION

The mean A-B gap was smaller after Type III tympanoplasty than after Type IV tympanoplasty. The magnitude of the A-B gap was greatest at 4 kHz in both procedures.

PORP vs. TORP: a meta-analysis

After the surgical procedure of ossicular chain reconstruction, the effectiveness and/or stability of partial ossicular replacement prosthesis (PORP) or total ossicular replacement prosthesis (TORP) were systematically compared and evaluated using meta-analysis. A total of 40 eligible investigations with 4,311 subjects were included in our study. There was a significant difference in the effectiveness of the reconstruction of the ossicular chain between PORP and TORP; the data showed a combined risk ratio (RR) of 1.28 (95 % CI 1.17-1.41, p < 0.00001), but no notable difference was obtained in staged procedures subgroup and cholesteatoma subgroup, with a combined RR of 1.13 (95 % CI 0.60-2.11, p = 0.70) in staged procedures subgroup and RR of 2.60 (95 % CI 0.20-36.21, p = 0.59 in cholesteatoma subgroup). There was a statistically significant difference in the stability of the prostheses in long-term follow-up, with a combined RR of 0.37 (95 % CI 0.16-0.85, p = 0.02), but no significant difference was observed in the total sample, with a combined RR of 0.64 (95 % CI 0.40-1.03, p = 0.06). Our overall results suggest that the effectiveness of PORP was higher than TORP, except within staged procedures subgroup and cholesteatoma subgroup. In addition, the stability of PORP was significantly superior to TORP in long-term follow-ups, but no significant effect was detected in the general study.

Comparison of round-window membrane mechanics before and after experimental stapedotomy

BACKGROUND

Surgical intervention within the area of the middle ear always leads to alteration of conditions in its biomechanical system. This fact may provide an explanation for the lack of expected auditory outcome, although an apparently good anatomic outcome was obtained. In the case of stapedotomy, the majority of patients report lack of satisfactory results for frequencies above 2,000 Hz. The effect has not been experimentally investigated yet.

METHODS

This study, conducted in four human temporal bones, yielded a record of round-window membrane vibration amplitude and phase in the frequency function (400 Hz-10 kHz) at the sound intensity level of 90 dB administered to the external auditory canal in a physiologic condition and following implantation of a Teflon piston stapes prosthesis. The procedure of experimental stapedotomy was performed with the tympanic membrane preserved from the maximally dilated approach through the posterior tympanotomy.

RESULTS

Stapes Teflon piston prosthesis implantation was found to cause approximately fivefold lower amplitude of round-window membrane vibrations compared to a physiologic situation for frequencies above 2 kHz in particular.

CONCLUSIONS

After stapedotomy, with the use of a Teflon piston prosthesis, stimulation of inner ear structures diminishes, especially in higher frequencies.

Experimental investigation of rotational tomography in reconstructed middle ears with clinical implications

A large air-bone-gap after ossiculoplasty may be due to a malpositioned or displaced prosthesis. Rotational tomography (RT) has the potential to provide high-resolution images of implants without artifacts and with less radiation dosage than CT scan. Twenty-seven temporal bone specimens underwent measurements of middle ear transfer function using Laser-Doppler-Vibrometry (LDV) before and after placement of ossicular replacement prostheses (PORPs, TORPs) made of titanium. RT was performed on all specimens. RT allowed 3-dimensional viewing of the temporal bone, accurate localization of implants within the reconstructed middle ear and determination of angles between the inserted prostheses and the tympanic membrane (TM) and/or the malleus handle (MH). Presence or absence of contact between the implant and the TM, malleus or stapes could be clearly visualized. Displaced prostheses were readily identified. The functional LDV-measurements for TORPs showed a trend favoring coupling to the malleus handle, while for PORPs, coupling to the TM was favored. For PORPs, sound transmission was worse with increasing angles between the PORP and stapes superstructure (p<0.05). Following our experimental results RT is an innovative, relevant and useful imaging technique to obtain immediate postoperative feedback after ossicular reconstruction and to precisely determine the position of middle ear implants.

'Umbrella' graft tympanoplasty

OBJECTIVES

Tympanoplasty continues to pose a challenge in developing countries, where treatment cost and lack of compliance with second stage surgery are often important factors in determining the surgical strategy. This study aimed to determine the effectiveness of the newly developed, 'umbrella' autograft.

MATERIALS AND METHODS

In 22 patients suffering chronic suppurative otitis media, in whom the incus and stapes suprastructure were found to be absent during surgery, reconstruction was achieved using cartilage-malleus umbrella graft assembly. Six-month post-operative results were evaluated on the basis of average hearing gain, measured at 0.5, 1, 2 and 3 kHz.

RESULTS

At six months post-operatively, 77.3 per cent of patients showed hearing improvement. Audiography at this time indicated significant improvement (p < 0.001), suggesting that this hearing gain may stand the test of time.

CONCLUSION

Umbrella graft tympanoplasty appears to be a promising technique in terms of cost-effectiveness and the autologous nature of implant materials.

Partial ossicular reconstruction: comparison of three different prostheses in clinical and experimental studies

OBJECTIVE

To compare the reconstruction results of a long incus process defect using 3 different partial ossicular replacement prostheses (PORP).

STUDY DESIGN

Temporal bone experiments and retrospective case review.

SETTING

Tertiary referral center. EXPERIMENTAL MATERIAL AND PATIENTS: The experimental study was performed on 18 temporal bones; 66 patients with retraction pockets, chronic otitis media with or without cholesteatoma.

INTERVENTIONS

Ossiculoplasty using 3 different PORP: titanium angle prosthesis, autologous incus interposition, and titanium clip prosthesis.

MAIN OUTCOME MEASURES

Laser Doppler vibrometry in temporal bones measured transmission properties of the PORP. Patients were retrospectively assessed up to 5 years after surgery. Audiologic data were analyzed for preoperative and postoperative air conduction and air-bone gap at 0.5, 1, 2, 3, and 4 kHz. Statistical analyses compared the outcome in the experimental and clinical setting.

RESULTS

Experimentally, the titanium PORP showed similar transmission properties because the overall difference to the intact specimen was -4.14 +/- 0.59 dB for the titanium angle prosthesis and -4.61 +/- 0.57 dB for the titanium clip prosthesis. The transmission after an autologous incus interposition was significantly worse (-9.32 +/- 0.39 dB, p < or = 0.001) compared with the other prostheses. Patients' mean postoperative air-bone gap was 25.5 +/- 1.2 dB and less than 20 dB in at least 66% of cases without any significant differences between the groups.

CONCLUSION

In the clinical setting, the confounding factors that influence the acoustic outcome after partial ossiculoplasty obscure the prosthesis-related transmission factors that can otherwise be derived in the experimental setting. The results do not generally favor the use of 1 specific prosthesis, rather they suggest that the correct choice of a prosthesis be based on the anatomic and pathophysiologic conditions found in the individual patient.

Middle ear cavity and ear canal pressure-driven stapes velocity responses in human cadaveric temporal bones

Drive pressure to stapes velocity (V(st)) transfer function measurements are collected and compared for human cadaveric temporal bones with the drive pressure alternately on the ear canal (EC) and middle ear cavity (MEC) sides of the tympanic membrane (TM), in order to predict the performance of proposed middle-ear implantable acoustic hearing aids, as well as provide additional data for examining human middle ear mechanics. The chief finding is that, in terms of the V(st) response, MEC stimulation performs at least as well as EC stimulation below 8 kHz, provided that the EC is unplugged. Plugging the EC causes a reduced response for MEC drive below 2 kHz, due to a corresponding reduction of the pressure difference between the two sides of the TM. Between 8 and 11 kHz, the MEC drive transfer functions feature an approximately 17 dB drop in magnitude below the EC drive case, the cause of which remains unknown. The EC drive transfer functions reported here feature significantly less magnitude roll-off above 1 kHz than previous studies [with a slope of -2.3 vs -6.7 dB/octave for Aibara et al., Hear. Res. 152, 100-109 (2001)], and significantly more phase group delay (134 vs 62 micros for Aibara et al.).

Längenvariable Titanprothesen bei Typ-III-Tympanoplastik

INTRODUCTION

For type III tympanoplasty by partial ossicular replacement prosthesis (PORP) or total ossicular replacement prosthesis (TORP), the length of the prosthesis must match the individual intraoperative anatomical and physiological characteristics.

MATERIALS AND METHODS

Databanks were used to determine the necessary sizer length of the sizer disc. The measurement template for the size of the cartilage to overlay the prosthesis headplate was derived from the headplates of the Tübinger titanium prostheses (TTP) and the Dresdener titanium prostheses. Finally all functions were integrated into a synthetic plate.

RESULTS

The result was a simple and reasonably priced disposable multifunctional instrument (Tübinger sizer disc TSD) which allowed an exact measurement for every prosthesis in TORP and PORP. For the TTP-Variac, the TSD enabled the simple intraoperative production of prostheses with the length desired by the surgeon. For PORP the TSD enabled an adaptation of the diameter of the prosthesis foot for TTP, TTP-Vario and TTP-Variac and provided a template for the size determination of the cartilage overlay of the titanium prosthesis head. The sizers and the resulting prostheses were used for initial tympanoplastic operations. Audiometric investigations carried out 6 weeks postoperatively gave results corresponding to those previously obtained in a study with TTP and TTP-Vario using the old instrumentation.

CONCLUSIONS

The new instrumentation leads to an improvement of the intraoperative practicability and a simplification. The audiological results remain the same.