Total Ossicular Reconstruction Prostheses 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.

Long-term outcomes following pediatric endoscopic titanium ossiculoplasty: A single-institution experience

IntroductionEndoscopic ossicular chain reconstruction (OCR) in adults has demonstrated equivalent outcomes to the traditional microscopic approach. Less data exist on endoscopic OCR outcomes in children, who have unique considerations including a smaller transcanal corridor and variable pathology. The purpose of this study was to investigate surgical and audiometric outcomes in children undergoing fully endoscopic and endoscopic-assisted OCR in both the short and long-term. MethodsRetrospective review of all children (<17 years) who underwent endoscopic OCR at one tertiary care center between 2017 and 2021. Children undergoing primary and revision endoscopic OCR with either partial (PORP) and total ossicular reconstruction prostheses (TORP) were included. Children undergoing surgery for juvenile otosclerosis or congenital stapes fixation, or any child receiving a stapes prosthesis were excluded. Primary outcome measures were post-operative change in 4 frequency (500 Hz, 1, 2, 4 KHz) air conduction pure tone average (AC PTA) and change in air-bone gap (ABG). Secondary measures included need for readmission and/or revision surgery, complication rate, and surgery duration. ResultsSeventeen patients met inclusion criteria. Average age was 11.3 years (range, 5–17 years); 14 were male. A variety of fixed length, titanium total and partial prostheses were used. The most common prosthesis length was 2 mm (range 2–5 mm), and there were no intra- or perioperative complications. Mean long-term follow-up was 2.6 years. Most common pathology was congenital cholesteatoma (11/17, 64%), followed by chronic otitis media with tympanic membrane perforation (5/17, 29.4%), and extruded prosthesis (1/17, 5.9%). Intraoperatively, the most common finding was incus erosion (10/17, 58.8%), followed by malleus erosion (6/17, 35.3%), stapes erosion (4/17, 23.5%), and stapes absence (4/17, 23.5%). Eight children (47%) were reconstructed with PORPs, and 9 children (52.9%) were reconstructed with TORPs. Average ABG improved from 36.8 dB preoperatively to 19.9 dB postoperatively in the short-term and remained stable at 19.5 dB in the long-term. Average short-term ABG improvement was 4.2 dB for PORPs and 18 dB for TORPs. In the long-term, average ABG improved by 2.3 dB in PORPs and 13.4 dB in TORPs. PORPs had higher rates of ABG closure and lower AC PTAs than TORPs in the long-term. DiscussionEndoscopic ossiculoplasty is a viable option in children presenting with ossicular erosion from various causes. Audiometric improvement following endoscopic partial and total ossicular reconstruction remains stable over time, with a preference towards partial in the long-term, and mirrors published outcomes for microscopic surgery.

Can the unmodified incus be used for a simpler, more cost-effective functional ossicular chain reconstruction? A retrospective clinical study.

To evaluate patients' hearing outcomes after ossicular chain reconstruction using unmodified autologous incus. A single-centred, retrospective study of patients who underwent incus interposition between June 2010 and October 2017 was conducted at a Dutch secondary referral centre. This paper describes a chart review of patients who presented with erosion of the long process of the incus due to atelectasis or cholesteatoma who were treated with an unmodified incus interposition. The main outcome measures were: post-operative air-bone gap and level of air-bone gap closure. Thirty-three ears of 32 patients were included. Follow-up duration ranged from six weeks to seven years. A mean post-operative air-bone gap under 25 dB was considered successful; this was achieved in 25 patients (76 per cent), 20 (91 per cent) in the partial ossicular reconstruction prosthesis group and 5 (45 per cent) in the total ossicular reconstruction prosthesis group. This difference was statistically significant (p = 0.007). Successful preservation and improvement of hearing was observed in most patients. As expected, the closure rate in the partial ossicular reconstruction prosthesis group was better. Longer follow-up studies with larger case numbers are needed to assess whether further reconstruction techniques are necessary.

Single centre experience of ossiculoplasty using different materials: a subjective and objective evaluation

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Chronic otitis media has serious impact over the ossicular integrity in middle ear resulting in ossicular necrosis and various grades of hearing loss along with other associated symptoms. Tympanomastoidectomy with ossicular reconstruction using various materials can improve the symptoms.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; A retrospective study of 50 patients underwent tympanomastoidectomy with ossiculoplasty in Department of ENT and Head and Neck Surgery at AIIMS Patna from April 2017 to 2018. Patients with chronic otitis media having ossicular necrosis with ABG (air bone gap) more than 25 dB were included in this study. PORP (partial ossicular reconstruction prosthesis) and TORP (total ossicular reconstruction prosthesis) were used as ossicular reconstruction after clearance of disease. This study was expressed as subjective and objective evaluation following ossiculoplasty. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Fifty patients having chronic otitis media with decreased hearing and other associating symptoms were included in this study. Preoperative air conduction threshold was 55.32 dB with preoperative ABG was 44.24 dB. Postoperative result was summarised as postoperative AC threshold was 32.72 dB with gain of 22.60 dB with ABG 25.45 dB.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Chronic otitis media may lead to ossicular necrosis and various grade of hearing loss. A proper technique and skilled tympanomastoidectomy with ossiculoplasty can improve the symptoms of chronic otitis media.&lt;/p&gt;

Effect of a boomerang-shaped Conchal cartilage graft for Type three Tympanoplasty on Hearing.

Introduction Chronic suppurative otitis media atticoantral disease (CSOM-AAD) is often associated with ossicular erosion resulting in significant hearing loss. Absence of the stapes suprastructure is a poor prognostic indicator of hearing outcome, which necessitates an effective reconstruction technique for ossicular continuity and restoration of middle ear volume. In the present study, we used a boomerang-shaped conchal cartilage graft. Objective To evaluate the improvement in hearing using a boomerang-shaped conchal cartilage graft for Type III tympanoplasty in cases of CSOM-AAD in which the stapes suprastructure was absent and to study the incidence of intraoperative/postoperative complications of this procedure. Method A total of 21 patients with CSOM-AAD who were found to have absent stapes suprastructure intraoperatively were included. A boomerang-shaped conchal cartilage graft was placed over the stapes footplate for reconstruction following canal wall down mastoidectomy. Pure tone audiogram (500, 1,000, 2,000 and 4,000 Hz) was done preoperatively and at 12 weeks postoperatively. Hearing outcome and incidence of complications were noted. Results There was a statistically significant reduction in the hearing loss for air conduction and air-bone gap (ABG) of 6.1 dB and 6.9 dB respectively ( p < 0.05). Air-bone gap < 30 dB could be achieved in 71.4% of the patients as compared with 23.8% preoperatively. No significant difference was noted in the bone conduction threshold (p > 0.05). A better hearing outcome was observed at higher frequencies (2,000, 4,000 Hz). No major complications were encountered. Conclusion A boomerang-shaped conchal cartilage graft is effective when used for Type III tympanoplasty, especially at higher (2,000, 4,000 Hz) frequencies, and is comparable to newer materials such as titanium total ossicular reconstruction prosthesis (TORP). No major intraoperative/postoperative complications were noted.

Total and partial ossiculoplasty in children: Audiological results and predictive factors

ObjectiveTo assess ossiculoplasty results in children and screen for predictive factors of efficacy. Patients and methodsSeventy five children undergoing ossiculoplasty between 2001 and 2014 in a pediatric ENT department were included. The following data were collected and analyzed: demographic data, surgical indication, history of tympanoplasty, contralateral ear status (healthy, affected), preoperative hearing thresholds, surgical technique, intraoperative findings, and ossicular chain status at eardrum opening. Audiological results were reported according to American Academy of Otolaryngology-Head and Neck Surgery guidelines. ResultsForty eight patients were included in the total ossicular reconstruction prosthesis (TORP) group. Mean age at surgery was 9.9years. Mean follow up was 2.7years. Mean air-bone gap (ABG) closure to within 20dB was achieved in 40% of cases at medium term (12 to 18 months after surgery). Air conduction (AC) threshold ≤30dB was achieved in 68% of cases. AC threshold improved by 14.6dB and 8.7dB at medium and long-term follow-up, respectively. A significant correlation was found between success rate and absence of history of tympanoplasty. The success rate was higher for primary than for revision procedures. Twenty seven children were included in the partial ossicular reconstruction prosthesis (PORP) group. Mean age was 9.5years, and mean follow-up 2.6years. Mean air-bone gap (ABG) closure to within 20dB was achieved in 75% of cases at medium term. AC threshold ≤30dB was achieved in 75% of cases AC threshold improved by 9.3dB and 5dB at medium and long-term follow-up, respectively. No predictive factors for success were found in the PORP group. ConclusionThe present study suggested that total ossiculoplasty leads to better results when performed in first-line. It also confirmed that functional outcome is better in partial than total ossicular reconstruction prosthesis.

Revision stapedectomy with bone cement: are results comparable to those of standard techniques?

To examine hearing results in revision stapedectomy using hydroxyapatite bone cement for incus necrosis. Retrospective case series. Tertiary care academic medical center. Eligible patients underwent revision stapedectomy for otosclerosis using hydroxyapatite bone cement to reconstruct incus necrosis between March 2007 and August 2013. Patients were excluded for insufficient audiometric data or an operative indication other than otosclerosis. Revision stapedectomy performed with standard stapes piston prostheses using hydroxyapatite bone cement to stabilize the prosthesis. Air-bone gap (ABG), air-conduction and bone conduction pure-tone audiometry thresholds, and speech discrimination scores (SDSs) were obtained preoperatively and postoperatively. The preoperative result closest to the date of surgery was compared with the postoperative result farthest from the date of surgery. Twenty-seven patients (aged 32-83 yr) met criteria and were included in the study. Average duration of follow-up was 7 months (range, 1-39 mo). Postoperative closure of the ABG to within 10 dB was achieved in 77.8% of cases. Closure to within 20 dB was achieved in 96.3%. The average postoperative ABG was 8.1 dB (range, 0-24 dB). The average SDS change was +7.4% (-12% to +92%). There were no cases of significant postoperative sensorineural hearing loss by bone conduction pure-tone audiometry. Use of hydroxyapatite cement for treatment of incus necrosis in revision stapedectomy provides excellent hearing outcomes and is a reasonable alternative to total ossicular reconstruction prosthesis or malleovestibular prosthesis techniques.

Hearing Outcomes after Revision Stapedectomy Managed with Total Ossicular Reconstruction Prostheses

Objectives: (1) Describe the use of total ossicular reconstruction prostheses (TORP) during revision stapedectomy in the setting of advanced incus erosion. (2) Analyze the short- and medium-term audiometric results of TORP for revision stapedectomy. Methods: A retrospective case review at a tertiary neurotological referral center was conducted of nineteen cases of revision stapedectomy where TORP reconstruction was performed due to advanced incus erosion. Pre- and postoperative bone conduction (BC-PTA) and air conduction (AC-PTA) pure tone averages (0.5, 1, 2, 3 kHz) including high tone bone conduction (1, 2, 3 kHz), air-bone gap (ABG), and speech discrimination scores (SDS) were measured. Short-term (3 weeks) and medium-term (median, 12 months) hearing outcomes were measured. Results: Among 19 ears undergoing revision stapedectomy managed with TORP reconstruction, the average number of previous revision attempts was 1.2 (SD, 2; range, 1-6). The preoperative BC-PTA was 32.1 dB preoperatively while the preoperative AC-PTA was 65.3 dB. The mean postoperative ABG significantly decreased to 16.6 dB (SD, 13.68; range, −2.5 to 46.3 dB, P &lt; .003) with mean follow-up of 15 months (SD, 18.8; range, 0.75-54 months). A nonsignificant mean high tone BC-PTA decrement of 3.8 dB (SD = 5.9, range −8.33 to 18.33 dB, P = .427) was observed including one ear with no responses postoperatively. No further revisions were noted in follow-up. Conclusions: Total ossicular reconstruction in the setting of previous revision stapedectomy with limited incudovestibular reconstructive options may lead to favorable hearing outcomes but carries an increased risk of sensorineural hearing loss.

Total Ossiculoplasty

Review experience using a titanium TORP with a footplate shoe; compare early and long-term hearing results and complications with those obtained using a TORP alone. Retrospective chart review. Tertiary referral neurotologic private practice. Patients undergoing total ossicular replacement with a titanium prosthesis (total ossicular reconstruction prosthesis [TORP]); 74 with a TORP + footplate shoe and 62 with TORP alone. Ossicular chain reconstruction with a titanium TORP. Short- and long-term air-bone gap (ABG), change in ABG from preoperative to postoperative and from postoperative to last recorded follow-up, sensorineural hearing loss. The shoe group had a smaller mean postoperative ABG (17.7 dB versus 21.6 dB, p ≤ 0.048) and a greater average amount of closure in ABG (21.9 dB versus 13.2 dB, p ≤ 0.004), but there was no significant difference in percentage of patients achieving a postoperative ABG of 20 dB or lesser (57.4% versus 61.6%). There were no differences between groups at long-term follow-up or in amount of change in ABG from postoperative to last audiogram or in amount of change in sensorineural hearing from preoperative to postoperative. Although surgical factors (number of previous surgeries, and presence of a cavity) impacted outcomes, there were no interactions with prosthesis group and no differences in complications between groups. Ossicular reconstruction still presents challenges. A titanium prosthesis with a "shoe" for stabilization may offer advantages. Results in this study consistently favored the TORP + shoe group,although not all differences achieved statistical significance. A larger study might better define possible advantages of the shoe prosthesis for specific subgroups of patients.

Preliminary Hearing Results of Tympanomastoidectomies Using Titanium Prostheses: Scenario in a Developing Country

The study was done to review postoperative hearing gain of patients with different Middle Ear Risk Index (MERI) undergoing Tympanomastoidectomies with titanium prostheses reconstruction. A Retrospective chart review was performed from September 2009 to December 2011. Of the 17 cases, 9 had moderate MERI while 8 had severe MERI. 9 patients underwent Tympanomastoidectomy with Total Ossicular Reconstruction Prostheses (TORP) and 8 with Partial Ossicular Reconstruction Prostheses (PORP). Hearing gain of 25.31 dB was achieved in cases with moderate MERI compared to 29.37 dB in severe MERI. Less than 20 dB average air-bone gap was achieved in 75% of PORP and 77.77% of TORP reconstructions. In developing countries with limited resources, decision regarding ossicular reconstruction should be made taking into account MERI, intra operative findings and type of surgery. Best results are achieved in cases of CWD with TORP and ICW with PORP.

Titanium ball joint total ossicular replacement prosthesis – Experimental evaluation and midterm clinical results

During reconstruction of the ossicular chain, there is a need to address the forces and loads caused by the ambient atmospheric pressure variations and the resulting tympanic membrane movements. It is understood that when a rigid middle ear prosthesis is inserted the malleoincudal joint, a keyfactor in controlling pressure variations in the middle ear space is bypassed. In this paper we describe a modified total titanium ossicular replacement prosthesis with an innovative micro ball joint in the headplate which is designed to compensate for tympanic membrane movements caused by atmospheric pressure variations. The characteristics of this modified prosthesis were examined in temporal bone experiments and compared to the standard titanium total ossicular reconstruction prosthesis. Sound-induced stapes footplate movements were investigated by means of a Laser vibrometer and revealed no significant differences between the two prostheses in vitro. Intraoperatively, the insertion of the modified prosthesis required more delicate handling. The angle between the shaft and the headplate was variable and ranged from 60 to 90° as estimated by the surgeon. Twelve consecutive patients were eligible for clinical evaluation. The pure tone average (PTA) air-bone gap after a mean follow up period of 32 months was 18.8 dB. Furthermore, no extrusion, dislocation or other adverse events were observed. We conclude that the modified total ossicular replacement prosthesis with integrated micro ball joint yields similar volume velocities of the stapes footplate in the laboratory experiments compared to the standard rigid prosthesis. The audiological and morphological results are encouraging and show that the mobile prosthesis headplate adjusting to the level of the tympanic membrane is a further step in the development of a physiological middle ear implant.This article is part of a Special Issue entitled “MEMRO 2012”.

A Micro-Computed Tomographic Study

To examine the anatomical relationship of the angles between tympanic membrane and stapes footplate and the variation of these angles among different temporal bones in order to characterize the optimal shape of total ossicular reconstruction prostheses (TORPs). Ten specimens of human temporal bones were prepared for examination with micro-computed tomography. Five of the 10 temporal bones were implanted with 3 types of TORPs before subjecting them to micro-computed tomography. The angles between tympanic membrane and stapes footplate were determined. The contact of the TORPs to these structures was assessed. The angle between the stapes footplate and the tympanic membrane was, on average, 25.9 degrees in a plane along the transverse axis of the stapes footplate and 24.6 degrees in a plane along the longitudinal axis of the stapes footplate. Consideration of these angles in TORPs resulted in an optimal contact with the tympanic membrane and stapes footplate, especially for prostheses with a large foot. TORPs should be adjusted in shape before insertion into the middle ear. Further developments should consider prostheses with preadjusted angles or appliances for the exact modification of the prostheses during surgery.

Clip Vibroplasty

To describe an active auditory rehabilitation method (clip vibroplasty) for conductive or mixed hearing loss in cases of a preserved stapes superstructure. After temporal bone experiments, the new clip vibroplasty was clinically used in 4 patients with chronic otitis media. A new titanium double clip device (clip vibroplasty) was developed for a standardized and effective coupling of the floating mass transducer of the Vibrant Soundbridge to the intact stapes. Temporal bone experiments using laser Doppler vibrometry were performed to evaluate the device's acoustic efficiency. The audiologic outcomes of the first 4 patients were analyzed. The subjective benefits and satisfaction were assessed using the standardized International Outcome Inventory for Hearing Aids in all patients. Transfer characteristics of laser Doppler vibrometry experiments; audiologic outcomes of the 4 patients. In the temporal bone experiment, coupling of the FMT using the titanium double clip support produced transfer characteristics across all tested frequencies comparable to our former total ossicular reconstruction prosthesis or an optimal round window application. The intraoperative application of the clip vibroplasty was uneventful in all cases. No signs of prosthesis dislocation were noted within the follow-up period of approximately 12 months. The audiologic outcome of the first patients showed good hearing gain in pure-tone and speech audiometry, with results that are unobtainable using a conventional air conduction hearing aid. The concept of a partial ossicular reconstruction prosthesis vibroplasty using a titanium clip support entails a straightforward procedure similar to a classic partial ossicular reconstruction prosthesis tympanoplasty. The unoccluded ear canal and the superior auditory performance offer an advantageous application of this "power clip" in cases of chronic middle ear dysfunction.

Ossicular Chain Reconstruction Using Titanium versus Hydroxyapatite Implants

Compare the efficacy of total and partial ossicular chain reconstruction using hydroxyapatite (HA) implants versus titanium (Ti) implants. Case series with chart review. Academic tertiary referral center and private practice. 404 patients underwent ossiculoplasty using either Ti or HA implants from June 1996 to September 2008. Patient data were collected retrospectively from the senior author's electronic database of surgical cases. The change in air-bone gap (ΔABG) (defined as the difference between the means of preoperative and postoperative ABG) was 9.9 dB for the HA group that received partial ossicular reconstruction prosthesis (PORP), 9.5 dB for the Ti PORP group, 12.3 dB for the Ti group that received total ossicular reconstruction prosthesis (TORP), and 10.0 dB for the HA TORP group. There was no statistically significant difference between the HA and Ti groups. There was no significant difference in hearing results between canal wall up (CWU) and canal wall down (CWD) cases in which mastoidectomy was performed. Four confounding factors (preoperative otorrhea, preoperative perforation, cholesteatoma, mastoidectomy performed) were analyzed using regression analysis. In the Ti PORP group, the presence of cholesteatoma was found to have a significant negative bias for hearing results. No statistically significant differences in hearing results were found between the HA and the Ti partial and total ossiculoplasty prostheses. No outcome difference was found between CWU versus CWD mastoidectomy groups for any type of implant used. A randomized, prospective study is necessary for a more definitive comparison of efficacy between HA and Ti OCR implants.

Experimental middle ear surgery in rabbits: a new approach for reconstructing the ossicular chain

This experimental animal study aimed at evaluating a new prosthesis to replace the ossicular chain; we developed a new technique for surgical implantation into the middle ear of rabbits. The rabbit middle ear is, owing to the relative anatomical dimensions involved, an ideal environment for implantation procedures involving the ossicles, as the surgical conditions are similar to those of the human middle ear. This study included a total of 34 approximately six-month-old female white rabbits (New Zealand) weighing between 3.2 and 4.4 kg. The implants used were constructed of ceramic materials (titania, TiO(2)) of various pore sizes. Directly prior to implanting the total ossicular reconstruction prostheses (TORPs), as well as at 28, 84 and 300 days after implantation, electric response audiometry was used to determine the hearing thresholds of the animals (bone conduction; click stimulus nHL). An erbium:YAG laser was used to excise the original ossicular chain. Following implantation, we were unable to detect any stenosis of the outer ear canal or perforation of the tympanic membrane. The conductive hearing threshold was in the range of 4.21 +/- 6.68 dB nHL (n = 131). The hearing level showed no significant difference before and after surgery (P < 0.05).

Kurz titanium prostheses in paediatric ossiculoplasty—Short term results

The objective of this study is to assess the efficacy of ossiculoplasty procedures in the paediatric population when the Kurz titanium ossicular prosthesis is used. Data was collected prospectively upon 14 ossiculoplasty cases using Kurz titanium prostheses. Audiological parameters using four frequency average (FFA(0.5, 1, 2 and 4kHz)) were assessed pre- and post-operatively. In the case of patients reconstructed using partial ossicular reconstruction prostheses, 7/9 (78%) achieved an air bone gap (<20dB) using FFA criteria. Parameters at 12-month follow-up suggested 4/5 (80%) patients reconstructed using total ossicular reconstruction prostheses achieved an air bone gap (<20dB) using FFA. The question of age and presence of co-existing cholesteatoma or tympanic membrane perforation does not appear to mitigate against performing ossicular reconstruction in this age group. Consequently, the results of this study suggest that the use of Kurz titanium prostheses is a feasible option to augment hearing in paediatric cases involving chronic otitis media. This is a significant finding especially in view of the added psychological burden of hearing difficulties carried by the paediatric population.

Ossiculoplasty with total hydroxylapatite prostheses anatomical and functional outcomes.

To evaluate the results of partial and total ossicular reconstruction prostheses entirely made of hydroxylapatite. A retrospective review of cases followed-up between 1997 and 2000. Tertiary referral center. One hundred adult patients (60 men and 40 women) were studied. The mean age was 55 years (range, 25 to 65 years). Fifty patients had a previous tympanoplasty. The series included 45 cholesteatomas (45%), 37 chronic otitis media without cholesteatoma (37%), 13 retraction pockets (13%), and 5 posttraumatic ossicular displacements (5%). A one-stage ossiculoplasty with a partial ossicular reconstruction prosthesis (n = 65) or a total ossicular reconstruction prosthesis (n = 35) was performed. This was associated with a simple mastoidectomy in 70 cases and a radical mastoidectomy in 10 cases. All patients were followed-up at 1 year, and 50 were reexamined 2 years after surgery. Clinical and audiometric data were collected in a database at each visit. A prosthetic extrusion was noted in two cases (2%). A prosthetic displacement occurred in 10 cases (10%). A revision surgery was carried out in 10 cases because of an ossiculoplasty failure or a disease recurrence. At 1 year, the residual air-bone gap was lower in cases with a partial ossicular reconstruction prosthesis than those with a total ossicular reconstruction prosthesis (16 +/- 9.3 versus 23 +/- 13.7 dB, p < 0.05). The gain in mean air conduction threshold was 21 +/- 12.8 dB in cases of partial ossicular reconstruction prosthesis and 19 +/- 11.3 dB in cases of total ossicular reconstruction prosthesis (not significant). Revision surgery, canal wall-down mastoidectomy, or cholesteatoma yielded poorer functional results. Partial ossicular reconstruction prosthesis and total ossicular reconstruction prosthesis entirely made of dense hydroxylapatite yielded high rates of air-bone gap reduction and high anatomic stability.

Wie verhalten sich metallhaltige Mittelohrimplantate in der Kernspintomographie?

Magnetic resonance imaging (MRI) has gained in frequency and importance as a diagnostic procedure. In respect to the close anatomical relationship in the temporal bone it is necessary to know whether it is hazardous to patients with metallic middle ear implants regarding displacement and rise in temperature. For the MR image quality artefacts caused by metallic prostheses should be low. Four different stapes prostheses made from titanium, gold, teflon/platinum and teflon/steel, a titanium total ossicular reconstruction prosthesis (TORP) and two ventilation tubes (made from titanium and gold) were tested in a 1.5 Tesla MRI machine regarding their displacement. All objects were first placed in a petri dish, then suspended from a thread and finally immersed in a dish filled with Gadolinium. Temperature changes of the implants were recorded by a pyrometer. None of the implants moved when they were placed in the petri dish or suspended from the thread. On the water surface the teflon/platinum and the teflon/steel pistons adjusted their direction with their axis longitudinally to the MRI scanner opening and the teflon/steel piston floated towards the MRI-machine when put close enough to the scanner opening. No rise in temperature was recorded. All implants showed as little artefacts that would still make an evaluation of the surrounding tissue possible. Patients with any of the metallic middle ear implants that were examined in this study may undergo MRI-investigations without significant adverse effects.

Congenital Absence of the Oval Window

From 1983 to 1987, seven patients with conductive hearing loss were found to have congenital absence of the oval window. Six of these patients underwent vestibulotomies and reconstruction with House wires or total ossicular reconstruction prostheses. Surgical findings included absent or rudimentary stapes in all cases, abnormal facial nerves in four cases, and abnormal long processes of the incus in four cases. All patients had normal external ear canals and tympanic membranes. Hearing initially improved 20 to 45 dB in four of the six patients reconstructed. Over time, however, much of this initial hearing gain was lost. A marked difference in hearing results was evident between this series of absent oval window cases and a recent series of major atresia cases.

Congenital absence of the oval window

From 1983 to 1987, seven patients with conductive hearing loss were found to have congenital absence of the oval window. Six of these patients underwent vestibulotomies and reconstruction with House wires or total ossicular reconstruction prostheses. Surgical findings included absent or rudimentary stapes in all cases, abnormal facial nerves in four cases, and abnormal long processes of the incus in four cases. All patients had normal external ear canals and tympanic membranes. Hearing initially improved 20 to 45 dB in four of the six patients reconstructed. Over time, however, much of this initial hearing gain was lost. A marked difference in hearing results was evident between this series of absent oval window cases and a recent series of major atresia cases.