Allograft stapes surgery for conductive hearing loss in patients with ossicular chain anomalies

An allograft stapes was used during surgical intervention for conductive hearing loss due to ossicular malformations in 11 ears of seven patients. The external auditory canal and tympanic membrane were normal in all ears. The surgical findings for the ossicles were stapes fixation (7 ears), stapes fixation with discontinuity of the incudostapedial joint (in both ears of one patient), a deformed incus and stapes crura compressed by the facial nerve (one ear in which the stapes was not fixed) and an anomaly of the incus and stapes combined with a dermoid cyst (in one ear in which the stapes was also not fixed). In all ears, the following procedures were performed: stapedectomy followed by sealing the oval window with a vein graft and placing an allograft stapes between the oval window and the lenticular process of the incus or the handle of the malleus. The allograft stapes was placed with its capitulum on the oval window in all cases, and fibrin glue was used for stabilizing the seal and the allograft stapes. The indications for stapedectomy for conductive hearing loss due to ossicular chain anomalies and the utility of allograft stapes are discussed.

Allograft stapes-incus assembly. Long-term results

In 35 patients with absence of the stapedial arch, with a history of radical surgery, and without ossicles, the head of an allograft stapes was placed on the patients' footplates and an allograft incus body on the top of this. The long-term results of this assembly, judging by different methods of analysis, are still somewhat better than those of 98 ears with approximately the same pathologic condition treated by an allograft incus as the columella between the footplate and fascia. The allograft stapes-incus assembly is an alternative method to the commonly used incudal columella. The allograft stapes has not been resorbed to a significant degree during the years after surgery.

The use of allograft stapes

Since 1981, we have used the stapes allograft, singly or in combination with homograft incus, in 20 cases of tympanoplasty and in 7 cases of fixed stapes. All of the allograft stapes discussed were procured, processed and stored in 1980 by the Hyogo Ear Bank, the first to be established in Japan. The stapes allograft was used in three situations: an intact posterior canal wall, an open mastoidectomy cavity, or a fixed stapes (postinflammatory, congenital or otosclerotic). Two modalities of positioning of the donor stapes were attempted: (1) the allograft stapes was placed in the normal position and a shaped incus or cortical bone or tragal cartilage was placed on the top of the stapedial head and connected and (2) the allograft stapes was placed in the upside-down position and the columella was placed on the stapes footplate. Better results were obtained with the allograft stapes placed in the normal position. A two-stage operation, first to place an allograft stapes in the normal position with myringoplasty and then ossiculoplasty, was preferable to one-stage middle ear surgery.

Homograft stapes in middle ear surgery

Descriptions are given of various uses of stapes homografts in tympanoplasty on ears with missing stapedial arch. The use of homograft stapes-incus assembly, placing the head of the homograft stapes on the patient's own footplate and on top of that an incus, is a method which at long sight has proved to afford better results than the use of an incus columella.

Allograft stapes-incus assembly. A new ossiculoplasty

In 45 patients with absence of the stapedial arch, including 24 with a history of radical surgery and without ossicles, the head of an allograft stapes was placed on the patient's footplate and on top of this an incus body, either as allograft or autograft. The results of this assembly, judging by different methods of analysis, are the same as in 45 ears having approximately the same pathologic condition treated by an autograft or allograft incus as the columella between the footplate and eardrum. The allograft stapes-incus assembly is an alternative method to the commonly used incudal columella, particularly in patients previously subjected to radical surgery in whom all ossicles are absent.

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.

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.