[Middle ear surgery in Mongolia--first results with middle ear prostheses]. / Erste Erfahrungen mit Prothesen in der Mittelohrchirurgie in der Mongolei.

BACKGROUND: Medical care of the Mongolian population is still far behind the standard of industrialised countries. Also in the field of otorhinolaryngology there are clear deficits in regard to an adequate diagnosis and treatment of difficult cases. Microsurgery of the ear is still in the very beginning due to missing essential equipment and surgical skills of the few ORL-units that exists in the country. The integration of tympanoplastic procedures into surgical routine is the main goal of a support programme that exists between the medical faculties of the universities of Wuerzburg (Germany) and Ulan Bator (Mongolia). The aim of this work is to present the outcome of these operations in Mongolia. METHODS AND PATIENTS: As a result of the continuous education and support programme it was possible to perform 90 tympanoplastic procedures between 2005 and 2006 in the local ORL center of Ulan Bator (EMJJ-clinic). The focus of this report is on the postoperative audiological outcome following reconstruction of the ossicular chain either using autologous ossicles or middle ear prostheses. Besides, prostheses made of polyethylene or Teflon (Russian production) as well as titanium prostheses (Kurz Company, Germany) were implanted. RESULTS: The final evaluation of the audiological results was performed 6 month postoperatively. The titanium prostheses provided the most favourable hearing improvement (mean 26 dB) when compared to the other materials (polyethylene 7 dB, Teflon 18 dB), but also compared to the autologous ossicles (8,6 dB). CONCLUSIONS: The standard tympanoplastic procedures, which were developed over decades, proved to be highly reliable also in a country with reduced medical care. The hearing results obtained especially with titanium prostheses demonstrated, that this highly biocompatible alloplastic material is the most suitable and reliable for middle ear reconstruction also in a difficult surrounding.

Histopathology of ossicular grafts and implants in chronic otitis media.

OBJECTIVES: We describe the histopathology of ossicular grafts and implants so as to provide insight into factors that may influence functional results after surgery for chronic otitis media. METHODS: Histopathologic observations were made on 56 cases: 50 surgical specimens and 6 temporal bone cases in which the graft was sectioned in situ. RESULTS AND CONCLUSIONS: Autogenous malleus, incus, and cortical bone grafts behaved in a similar manner and maintained their morphological size, shape, and contour for extended periods of time, at least up to 30 years. These histopathologic observations support the continued use of autograft ossicular and cortical bone grafts for middle ear reconstruction. Cartilage grafts developed chondromalacia with resulting loss of stiffness and showed a tendency to undergo resorption. Synthetic prostheses made of porous plastic (Plastipore, Polycel) elicited foreign body giant cell reactions with various degrees of biodegradation of the implants. Prostheses made of hydroxyapatite and Bioglass were enveloped by a lining of connective tissue and mucosal epithelium. The Bioglass material was broken down into small fragments and partially resorbed by a host response within the middle ear. These results warrant caution in the use of prostheses made of porous plastic or Bioglass.

[Use of autotransplants and implants in ossiculoplasty].

The paper presents a comparative analysis of efficacy of ossiculoplasty (OP) using different transplants. A total of 202 operations were performed. Prostheses made of the fragments of the auditory ossicles, or a cortical layer of the temporal bone (n=81), of nail plate (n=56), titanium implants (n=65) were applied. A satisfactory result was achieved in 72-87% ossiculoplasties. Functional outcomes of OP did not vary significantly with type and material of the prosthesis. Main causes of poor OP results were fixation or displacement of the prosthesis with fibrous tissue; in case of titanium prostheses -- perforation of the tympanic membrane with prosthesis extrusion.

Tympanoplasty using homograft tympanic membranes and ossicles.

The use of homograft materials in reconstructive, mastoid, and middle ear surgery is increasing. Not only are they useful and practical, but they also do the job well in both anatomical and functional restoration. Many encouraging reports have been written to support their use. Their advantages, in the opinion of the author, outweigh their cost since they can offer a more efficient, versatile, and better method of restoration of hearing in tympanoplasty surgery.

The use of homograft stapes.

Homograft stapes were used for ossicular reconstruction in 43 ears over a three-year period. The average hearing improvement was 7.9 db. These cases were divided into groups: those with an intact posterior canal wall and those with an open mastoid cavity. The latter group fared better, with an average improvement of 15 db. Fourteen of the 43 ears were subsequently re-explored. Satisfactory bony union between the homograft stapes and recipient footplate was found in eight cases, four cases showed poor bony union, and bony resorption of the homograft had occurred in two patiemise for reconstruction of the ear with a loss of the stapes arch, especially in the presence of an open mastoid cavity and thus a shallow middle ear.

Results of homografts in middle ear surgery.

Anatomical and hearing results following the use of the homograft tympanic membrane and ossicles either in combination or separately are reported for the period 1968 through 1975. The study is divided into two parts, the first covering the primary years 1968 through 1971, and the latter covering the last four years, 1972 through 1975. The original technique was to cover completely the homograft tympanic membrane with a canal skin graft. During the year 1969 new and different techniques were attempted. Unfortunately this resulted in a marked increase of graft failures; therefore, there was a prompt return to the original technique, which has been used without change throughout the study. The graft take rate for the first four years which included 1969 was 92%. There was a slight increase to 96% during the second part of the study. The hearing results show a greater discrepancy for the two periods with 89% of the patients receiving a satisfactory hearing result during the last four years, compared to 77% for the earlier period.

Radiologic and mechanical properties of inactivated ossicle homografts.

OBJECTIVE: This study examined the effects of old and new inactivation (sterilization) techniques on the radiologic and mechanical properties of ossicle homografts. MATERIALS AND METHODS: Ninety normal incuses and malleuses received either treatment with 1) 5% formaldehyde/cialit, 2) 1N NaOH, 3) 0.9% LpH, or 4) autoclaving at 134'C, or no treatment. All ossicles were assessed radiologically by high-resolution computed tomography. After imaging, all ossicles underwent mechanical testing by destructive axial compression in a mechanical testing machine measuring force and displacement. RESULTS: Ossicles treated with cialit, NaOH, or autoclaving showed a significant decrease of ultimate force and stiffness compared with controls. LpH treatment caused no such changes in these structural properties. Material properties of yield strength, ultimate strength, and elastic modulus were also altered by cialit, NaOH, and autoclaving, but were much more difficult to assess because of uncertainty in parameter estimates. There was a significant increase in radiologic density in autoclaved ossicles, a reduction in cialit- and LpH-treated ossicles, and no change in NaOH-treated ossicles. CONCLUSIONS: All tested inactivation procedures changed the biomechanical and/or radiologic properties of ossicle homografts. However, the new procedures used to inactivate infectious agents produced changes similar to the older treatments with formaldehyde/cialit. Human allografts are able to withstand harsh but safe sterilization procedures. The NaOH treatment seems to be the most suitable method for the future. The biologic (osteogenic) potentials of ossicle homografts treated with these new preservation/inactivation methods are still unknown. Further investigations are necessary to re-evaluate the clinical use of ossicle homografts in middle ear reconstructive surgery.

Non-ossicle homograft bone prostheses in the middle ear.

This thesis proposes the use of human cadaver non-ossicle temporal homograft bone as middle ear reconstructive material. Bone obtained from the otic capsule histologically resembles that of the ossicles more so than any other bone in the body. The otic capsule, due to its proximity to the middle ear, can be harvested with the middle ear structures when bone cores are obtained, making it easily accessible. These prostheses are cost effective because multiple prostheses can be sculptured from one temporal bone core. This paper further proposes the use and introduction of non-ossicle homografts in primary stapedectomy, as well as in selected cases to bypass the incus and the superstructure of the stapes. Audiological data is provided. Some of the grafts have been in the middle ear for up to 5 years. There have been no extrusions and no complications. The method of harvesting, preservation, and sterilization is presented, as well as a pictorial illustration of the finished product and its relation to the natural ossicles. One histological specimen is presented. On the basis of the audiologic results, as well as the fact that no ossicles have extruded and none have been resorbed, it is proposed that non-ossicle temporal bone homografts have a place in transplantation surgery.

Ossicular transplants: histologic findings in animals and man.

Numerous papers have been published in the past 15 years in which the authors attempted to predict the results of surgical procedures on humans by analyzing the findings in animals undergoing similar procedures. Our experience in analyzing animal and human temporal bones indicates that conclusions drawn on this basis are frequently invalid. We reviewed temporal bones of monkeys and cats that had had a variety of surgical procedures. There is much more middle ear fibrosis, particularly in the epithmpanum, in these animals than one finds in human temporal bones. In a number of animals in which middle ear procedures were performed, hydrops of the inner ear or labyrinthitis occurred. This has not been the experience in human middle ear surgical procedures. An extensive review of the literature indicates that most investigators are of the same opinion. However, there are still those who are performing experiments using ossicular transplants, stapedectomy techniques, etc., who attempt to correlate the findings in animals in anticipation of what the same procedures might do to the human middle and inner ear. It appears from our experience, and that of many other investigators, that the ultimate fate of ossicular repositioning and transplantation in various animals cannot be used to predict what might happen in human beings.

The fate of an ossicular allograft in tympanoplasty.

Correction of ossicular defects in tympanoplasty most commonly involves the use of commercially available prostheses or preserved allograft ossicles. Incus autografts and tragal cartilage autografts are also used by many surgeons. Presculptured preserved allograft ossicles have not been used widely, but are used almost exclusively by our clinic. The fate of ossicular grafts has been reported by a number of in investigators with evidence obtained at revision surgery. In this paper we will be able to trace the fate of a presculptured preserved autograft ossicle clinically and pathologically. The unique aspect of this study is the demonstration of the ossicular status in post mortem temporal bone dissection followed by histopathological serial section studies.

Homograft ossicles in tympanoplasty.

Homograft ossicles have been utilized in reconstructive middle ear surgery since 1964. In the first few years, simple repositioning of the incus was the method used. Due to the shortcomings of this procedure, a sculptured ossicle, the notched incus, was introduced in 1970 and this has gradually evolved into two standardized and reliable prostheses. In 1972 hearing results were published on the first 122 cases. An expanded study in 1977 reported in detail on 361 ears. The current study reports the results of 326 patients operated upon during the 5 year period of 1976 through 1980 and compares them with the previous studies. The overall hearing results are very similar for both series with little change being noted in the failure rate. However, in the successful categories progress seems to have been made in that a greater percentage of the fair to good results has been shifted to the excellent category. A new concept of ossicular reconstructions is demonstrated with the introduction of the notched incus with high and low profile, to compensate for differences in the stapedial mallear relationship.

Homografts in chronic ear surgery.

There has been a considerable expansion in the use of tympano-ossicular homografts in the past decade. The use of homograft tympanic membranes and homograft ossicles as well as combined tympano-ossicular homografts has been shown to be effective in reconstructive surgery for chronic otitis media. While homograft tympanic membranes are effective in the repair of perforations, temporalis fascia is at least as effective and more readily available. Therefore, the unique benefit of the tympano-malleal homograft (TMH) is that it is an effective way of replacing the malleus, the "building block" for reconstruction of the ossicular chain. The indications and techniques for the use of the TMH are presented and illustrated through representative cases. The inclusion of the TMH in the otologist's armamentarium offers another avenue for reconstruction of the chronically diseased ear.

Hearing results in tympanoplasty.

Recent reports from Scandinavian authors have put forth the concept that hearing improvement following tympanoplasty is seldom satisfactory and difficult to obtain. This view is contradictory to the experience of most American authors. A study, therefore, was undertaken to evaluate the hearing results obtained by this author through the use of homograft material in middle ear and mastoid reconstruction. These hearing results are categorized according to time periods, types of reconstruction, and materials used. The hearing statistics are all taken from audiograms obtained one year or more postoperatively. These correspond with the type of reconstruction employed such as an intact ossicular chain, absence of the malleus, absence of the superstructure of the stapes, or both. Other categories include tympanoplasty with mastoidectomy or reconstruction of the posterior canal wall with homograft knee cartilage. The surgical techniques are not discussed in this article because they have been detailed in previous publications.

Risk of transmission of human immunodeficiency virus infection during tympano-ossicular homograft: an experimental study.

It is generally agreed that middle ear reconstructive surgery performed with tympano-ossicular homografts produces superior functional results compared with prosthetic material, especially with respect to extrusion rate. The use of homografts, though, has been seriously hampered recently by the fear of transmission of human immunodeficiency virus (HIV) infection. In HIV-infected patients, the virus is primarily found in the cells of the lymphoid and monocytic lineage. The nature of the tissues in the eardrum and ossicles, mostly fibrous tissue and compact bone without marrow, suggests that little virus load should be found in homografts. Indeed, culturing minced homograft tissue from two HIV-infected donors with acquired immune deficiency syndrome (AIDS) in a sensitive culture system with PHA-stimulated lymphoblasts produced no virus. Before use, homografts undergo a fixation procedure in 5% formaldehyde and then are kept in a solution containing Cialit as a preservative. The authors therefore examined the capacity of formaldehyde and Cialit to reduce the infectivity of HIV in models of infected tissue as measured in vitro. The reduction of in vitro infectivity due to these treatments was at least 10(5)-fold and 10(2)-fold, respectively. Coupled with the low virus burden in tympano-ossicular tissue, our data suggests that the fixation procedure affords such a reduction in infectivity that the risk of HIV transmission, even from an HIV-infected donor, is vanishingly low.

Ossiculotympanic transplantation.

Continued investigations into current tympanoplasty problems have been carried out in the Eye and Ear Clinic, Royal Victoria Hospital, Belfast. Retrospective studies have been helpful in identifying some of the main problems responsible for many of our unsatisfactory results, both in the irradication of disease and the restoration of aural function. Prospective studies into the behavior of grafting materials for tympanic reconstruction in the experimental animal have led us to an overwhelming preference for natural materials as opposed to plastics or stainless steel. Both homologous and autologous bone and cartilage appear to offer good prospects in ossicular replacement techniques. The most satisfactory material we have used for repair of tympanic membrane defects continues to be either autologous or homologous temporalis fascia. The long-term success of these materials in functional restoration is utterly dependent on continued aeration of the tubotympanic cleft.

Tympanomastoid reconstruction: an operative procedure for anatomical and functional restoration of the radicalized ear.

A new operative procedure for the anatomical and functional restoration of both the middle ear and mastoid is described. The technique employs homograft tympanic membrane with ossicles en bloc for the middle ear reconstruction and a homograft dura form and autogenous bone pate is used to recreate the bony posterior ear canal wall. The reconstructed wall becomes hard viable bone in about one year. Results in terms of wall integrity, tympanic membrane survival and hearing are discussed. The mechanism of new bone formation is discussed with presentation of histologic findings.

Can acquired immunodeficiency syndrome and Creutzfeldt-Jakob disease be transmitted via otologic homografts?

Materials commonly employed in the preparation of otologic homografts such as ethanol and formaldehyde are effective in vitro in inactivating human immunodeficiency virus (HIV). However, to our knowledge, the complete permeation of homograft materials with preservative has not been demonstrated. Ethanol and formaldehyde have not been shown to be effective in inactivating the Creutzfeldt-Jakob agent. The literature on sterilization procedures for these agents is reviewed. Standard procedures for preparation of otologic homografts are examined. It is recommended that donor HIV serologic status be determined when otologic homografts must be used. Further research is required to determine the efficacy of otologic homograft sterilization techniques against HIV and Creutzfeldt-Jakob disease.

Tomography and xerotomography after reconstructive middle ear surgery for cholesteatoma.

In order to adequately visualize the ossicles and other fine structures in the middle ear, sophisticated radiological methods are essential. The temporal bone has been studied with hypocycloidal tomography using conventional films and xerotomography in 60 patients with cholesteatoma. In 53 of the patients xerotomography gave good results while conventional tomography gave good results in only 38 patients. The superiority of xerotomography to conventional radiological methods is stressed. The only drawback is the high radiation dose to the patient.

Antigenicity of tympano-ossicular homografts of the middle ear: analyses of immune response to viable and preserved grafts in animal models.

Primary and secondary response transplantation experiments in allograft tympanoplasty reveal that after various preservation procedures at least part of the original histoincompatibility between donor and recipient still exists. Clinical pathologic data are in accordance with this phenomenon. The abolished immune reactivity in successful allograft-tympanoplasty is placed in the light of acquired immunotolerance. The consequences of prior tissue-typing are discussed.

Laser stapedotomy minus prosthesis (laser STAMP): absence of refixation.

OBJECTIVE: To determine what percentage of patients with otosclerosis could successfully undergo a laser stapedotomy minus prosthesis over a 5-year period, and to determine the percentage of patients in whom refixation develops during follow-up. STUDY DESIGN: Retrospective case review of 136 patients (137 ears) who underwent primary surgery for otosclerosis. SETTING: An otology/neurotology tertiary referral center. PATIENTS: Patients were chosen if they had clinical evidence of otosclerosis without a history of otologic surgery. INTERVENTIONS: A standard stapes approach was used for all patients. For the laser stapedotomy minus prosthesis, a hand-held laser probe was used to vaporize the anterior crus of the stapes and perform a linear stapedotomy across the anterior one third of the footplate. If otosclerosis was confined to the fissula ante fenestram, the stapes became completely mobile. The stapedotomy opening was sealed with an adipose tissue graft from the ear lobe. MAIN OUTCOME MEASURES: Pure-tone audiometry with appropriate masking and auditory discrimination testing was performed before surgery, 6 weeks after surgery, and every year thereafter. RESULTS: Of the 137 cases, favorable anatomy and minimal otosclerosis allowed 46 (33.6%) of these patients to undergo laser stapedotomy minus prosthesis. Fifty-seven patients (41.6%) could not undergo the procedure because of extensive otosclerosis. The remaining 34 patients (24.8%) did not receive laser stapedotomy minus prosthesis because of other anatomic or technical difficulties. Of the 34 patients in the laser stapedotomy minus prosthesis group with more than 4 months follow-up, the average air-bone gap was closed from a mean of 22 dB (SD 10 dB) to 6 dB (SD 4 dB) 6 weeks postoperatively. Follow-up periods ranged from 5 months to 53 months (mean 767 days, SD 437 days). The long-term air-bone gap improved slightly to an average of 5 dB (SD 6 dB) in comparison with the sixth postoperative week value. CONCLUSION: Laser stapedotomy minus prosthesis is a minimally invasive procedure, which over the follow-up period has a very low incidence of refixation, as evidenced by a lack of progressive conductive hearing loss. The success of this procedure depends on the correct selection of cases. This procedure has been successfully performed on 33.6% of patients undergoing primary stapes surgery. Laser stapedotomy minus prosthesis seems to be a viable alternative to conventional stapedotomy that yields good results without evidence of refixation over an extended time.