Grafting techniques.

Grafting of the tympanic membrane is different and more difficult than skin grafting elsewhere on the body because it covers an air-containing cavity. The two main techniques of grafting are the overlay and underlay methods. The advantages, disadvantages, types of grafting materials, and surgical approaches of both the overlay and underlay methods are discussed and evaluated. This article also reviews the evolution of tympanic membrane grafting techniques and evaluates the causes behind success or failure.

Congenital absence of the long process of the incus.

OBJECTIVE/HYPOTHESIS: To review the case reports of three generations of one family, suffering from bilateral conductive hearing loss due to congenital absence of the long process of the incus. STUDY DESIGN: Review of the literature regarding hereditary congenital absence of the long process of the incus to determine its mode of inheritance such as autosomal dominant or X-linked. Also document the types and results of surgical repairs performed by previous investigators of this defect and compare them with the present study. METHODS: Three female patients of direct lineage. Mother, daughter, and granddaughter, who were personally seen, operated on, and followed up over a period of 26 years. RESULTS: All three female patients presented with similar symptoms and findings of hearing impairment since birth, with no history of ear infections, and with normal appearing tympanic membranes. However, they had severe conductive hearing loss with normal bone conduction and discrimination. Operative findings were identical in all three patients, with the incus ending in a blind stub, and with absence of the capitulum of the stapes. The type of ossicular reconstruction varied with the changing of times and advances in otologic surgery, as well as the prosthetic materials used. All three patients received improvement in their hearing, and this improvement has been maintained over the 26-year span of the study. CONCLUSIONS: Hearing loss due to congenital absence of the incus is uncommon but not rare. Interestingly, no other instance of inherited cases were reported in the literature. In this family the defect appears to be an inherited trait either due to an autosomal dominant mutation or an X-linked dominant inheritance. This abnormality is amendable to surgery, and any well-executed technique usually gives good hearing results.

Hydroxylapatite implants for otologic surgery.

This article reviews the evolution of ossicular reconstruction from the autograft incus through homografts to hydroxylapatite prostheses in use today. In this way, a tried and true design has been combined with a mass-produced biocompatible material to produce a versatile prosthesis that will give excellent and consistent hearing results.

Incus interposition and ossiculoplasty with hydroxyapatite prostheses.

This article traces the evolution of transplant material in ossicular reconstruction of the middle ear. The first transplant consisted of the body and short process of the homograft incus. It was repositioned or wedged between the stapes head and the manubrium of the malleus. Further modification consisted of the sculpture of prostheses from homograft incudes; these were known as the notched incus with short or long process. By means of a notch in the short process, they were locked in place. The final phase is the use of hydroxyapatite as a biocompatible material from which similar prostheses may be precisely manufactured. These hydroxyapatite prostheses, known as the incus and incus-stapes replacement prosthesis, appear to be well tolerated and to produce excellent hearing results.

Ossicular reconstruction in ears with cholesteatoma.

Ossicular reconstruction in ears with cholesteatoma is similar to ears without cholesteatoma involvement. The important difference is that all cholesteatoma must be meticulously and completely removed or the reconstruction will fail. Special prostheses of bone or hydroxyapatite are used to rebuild the conductive mechanism. If only the incus is absent, an incus replacement prosthesis is employed between the malleus and intact stapes. When the stapedial superstructure is also missing, the incus-stapes prosthesis is utilized. These prostheses are interlocking in that a notch created in the top of the body of the implant engages the malleus and a cup in the lower part slips over the stapedial head, or a shaft extends to the stapedial footplate when the stapedial crura are missing. In either case the patient hears by direct columellar pressure from the new tympanic membrane to the fluids of the inner ear. Care is taken to preserve the patient's tissues and anatomy for use in reconstruction. If the patient's malleus or posterior bony wall must be sacrificed to eradicate the disease, these structures are immediately rebuilt with homograft tissue so that an orderly rebuilding of the conductive components may proceed. If the cholesteatoma has been extensive or infected and the middle ear mucosa is of poor character, definitive reconstruction is delayed to a second stage.

Incus replacement prostheses of hydroxylapatite in middle ear reconstruction.

Hydroxylapatite is a calcium bioceramic that has the same chemical composition as living bone, Ca10 (PO4) 6 (OH) 2. Since 1970 it has been used as a material in reconstructive prostheses and augmentation of lost tissues in various surgical specialties including maxillofacial surgery, plastic surgery, otolaryngology, and orthopedics. For over 20 years the author has used autograft and homograft ossicles in tympanoplasty. These incudi have been modified into prostheses that were utilized in ossicular reconstruction. During this time two principle prostheses have evolved, the notched incus with short and long processes. The short process prosthesis is used with an intact stapes, whereas the notched incus with long process carries the sound pressure directly to the stapedial footplate. These prostheses have been successful in improving and maintaining hearing following tympanoplasty. Unfortunately, however, the use of human tissue has certain limitations: it is not readily accessible and has a limited shelf life. Furthermore, clinicians are wary of using homograft tissue as concern over the AIDS virus spreads. Therefore it was felt prudent to develop a manmade prosthesis that would as nearly as possible match the advantages of living bone. Hydroxylapetite most nearly met those qualifications.

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.

The sleeve autograft in congenital cholesteatoma.

An epithelial cyst behind an intact tympanic membrane with no previous history of ear infections is an unusual but not infrequent finding in children. If it is recognized early and completely removed, a permanent cure is obtained. However, if it is unrecognized or poorly treated, there may be far-reaching complications. The conventional technique of creating a tympanomeatal flap to remove the congenital cholesteatoma is often unsatisfactory. This is because the cyst may be located in the anterior-superior quadrant and extend beneath the malleus. It therefore becomes impossible to accomplish a complete removal and still preserve auditory function. This leads to incomplete removal with recurrence and subsequent radical removal with loss of auditory function and alteration of normal anatomy. A technique is presented whereby the canal skin, malleus, and cholesteatoma are removed en bloc. Once outside the confines of the bony ear canal, the tympanic membrane is inverted and the epithelial cyst removed under direct vision. The eardrum-malleus-canal skin autograft is then replaced in anatomical position and the hearing reconstructed with a homograft notched incus. This technique has been utilized in nine cases over the past 10 years. Case reports demonstrate the anatomical and functional results.

The homograft tympanic membrane after 12 years.

The homograft tympanic membrane has been utilized in reconstructive middle ear surgery since 1968. Previous reports describing its preservation and use were published in 1971, 1972, 1976 and 1978. Throughout this time the same preservative of 70% ethyl alcohol and the same surgical technique of covering the transplant with canal skin or fascia has been employed. These transplants have been used to supplement, not replace, other grafting tissues, and to improve the graft-take rate and hearing results. The graft-take rate has averaged over 90% for the past 12 year and 98% for the past 5 years. The hearing results have been satisfactory in 69 to 95% of the cases depending on the associated ossicular reconstruction. Furthermore these results have been consistent and have not deteriorated with the passage of time.

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.

Aeration of the middle ear and mastoid in tympanoplasty.

In order to achieve a good hearing result following tympanoplasty it is necessary to maintain an aerated middle ear space. Poor Eustachian tube function is most commonly blamed in cases of failure to obtain an adequately aerated middle ear following tympanoplasty. Although this may be the true etiology in some cases, middle ear adhesions, loss of support of the posterior canal wall and inadvertent blockage of the Eustachian tube orifice by graft material may be contributing factors. Aeration of the mastoidectomy cavity is also important to prevent collapse of the posterior canal wall, retraction pockets and to insure an adequate air reserve. Surgical techniques for prevention of these complications and a means of bypassing the totally blocked Eustachian tube are discussed.

Results of reconstructive mastoidectomy with homograft knee cartilage.

The technique of reconstructing the posterior canal wall with homograft knee cartilage originally described in 1972 is reviewed and refinements are presented along with additional cases. The homograft knee cartilage is used in conjunction with the homograft tympanic membrane and ossicles to rebuild the middle ear and mastoid as near as possible to anatomical configuration and function. Anatomical follow-up of one year or more is reported on 63 ears. Satisfactory results were obtained in 36 of these ears or 57% of the total. Hearing results are reported overall and in relation to different types of reconstruction. One year or more follow-up demonstrates satisfactory hearing with an air-bone gap of 20 db or less in 77% of the postoperative ears.

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.

Hearing and anatomical results with homograft tympanoplasty.

Homograft tympanic membranes and ossicles have been found to be a valuable asset in tympanoplasty surgery. The homograft tympanic membrane has been used in conjunction with a canal skin graft with a graft take rate of 94 per cent. Anatomical results have been gratifying in that most patients are totally rehabilitated and may swim or shower without restrictions. The homograft incus has been sculptured into prostheses to reconstruct the sound conduction mechanism, both at the initial procedure and in revision cases to improve the hearing.