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Use of an ionomer bone cement is described for repairing the ossicular middle ear system in revision stapes surgery. The cement was used to enlarge an eroded inadequate incus to allow placement of a new stapes prosthesis. Reconstruction of the incus with this new bone cement was readily performed and hearing results after 2 years of follow-up have been promising.
The frequency and possible causes of erosion and necrosis of the long process of the incus induced by various types of prostheses following stapes surgery for otosclerosis are discussed. Between 1987 and 1995, 1144 stapes operations were performed including 117 revisions of stapes surgery performed by third parties and 27 revisions performed by the author. For the first time, necrosis of the long process of the incus caused by teflonplatinum piston is described on the basis of findings in five cases, in which the platinum loop had completely transmigrated the incudal process in a medial direction. By using pictures of the teflon-platinum piston and a gold piston taken by a scanning electron microscopy and a comparison between the use of a teflon-wire piston and a gold piston in two operations, an hypothesis is made that the winding grooves in the surface of the teflon shaft together with impaired middle ear mechanics were the main causes of a scar being contracted in the direction of the oval window niche with resulting necrosis of the incudal process. Requirements for an optimum stapes prosthesis are summarized as a result of the operative observations made.
The connection between the long process and the lenticular process of the incus is extremely fine, so much so that some authors have treated the lenticular process as a separate bone. We review descriptions of the lenticular process that have appeared in the literature, and present some new histological observations. We discuss the dimensions and composition of the lenticular process and of the incudostapedial joint, and present estimates of the material properties for the bone, cartilage, and ligament of which they are composed. We present a preliminary finite-element model which includes the lenticular plate, the bony pedicle connecting the lenticular plate to the long process, the head of the stapes, and the incudostapedial joint. The model has a much simplified geometry. We present simulation results for ranges of values for the material properties. We then present simulation results for this model when it is incorporated into an overall model of the middle ear of the cat. For the geometries and material properties used here, the bony pedicle is found to contribute significant flexibility to the coupling between the incus and the stapes.
One of the most common ossicular problems in revision stapedectomy is the eroded incus. Revision surgery has been reported as successful in 70% to 80% of cases at 1 year. Little is written about long-term results or the association of erosion with various prostheses. We evaluated 83 cases from 1 to 20 years, including multiple revisions. In 23 cases the erosion was seen at initial stapedectomy. Surgery was performed with the patient under local anesthesia, with the use of the Lippy modified prosthesis. Initial success was seen in 72% (41/57), satisfactory results in 90%, no change in 5%, and none worse. At 10 years, success had declined to 50% (7 of 14), with 80% satisfactory. The numbers for multiple revisions were lower. Success in nonrevision cases was 90% (21 of 23), dropping to 86% at 10 years, with satisfactory results in 100%. The type of prosthesis associated with erosion was a crimped wire in 34% (24 of 70), a plastic strut in 23%, and a Robinsion prosthesis in 17%. We conclude that the risk of incus erosion appears less with the Robinson prosthesis. The Lippy modified prosthesis yields good long-term results, particularly when erosion is seen at initial stapedectomy. Results worsen with subsequent revision.
Ossicular necrosis is often associated with chronic adhesive otitis media. An unusual abnormality discovered in an incus removed during tympanoplasty is reported. The long process appears to have been grooved by pressure from the chorda tympani. An alternative theory to explain the vulnerability of the long process of the incus is suggested.
We report the use of an ionomeric based bone substitute to reconstruct the ossicles in their normal position. To reconstruct small defects of the incudo-stapedial joint, this bone replacement material is applied to the long process of the incus and the head of the stapes. After setting and hardening a stable contact to the adjacent bone is formed. The audiological results after reconstruction of small incus defects with ionomeric cement are discussed in comparison to stapedectomy and tympanoplasty.
Chronic inflammations of the middle ear are characterised by perforation of the tympanic membrane as well as hearing loss, due to disintegration in the incudostapedial joint. Usually the perforation is easily restored by means of available modern procedures; on the other hand, failure of the reconstruction of the ossicular chain, especially of the incudostapedial joint, is not uncommon. Hence, the improvement of hearing capacity is transitory, since later, due to scars, graft lateralisation results in a dislocation of the primarily reconstructed ossicular chain. The patient's hearing capacity is then as poor as it has been before surgery. The aim of this study is to demonstrate the ways of satisfactory reconstruction of the incudostapedial joint by means of glass-ionomer cement: 1. Scar tissue connecting the ossicles in slight defects of the incudostapedial joint can be stabilised by glass-ionomer cement leading to a reasonable sound transmission. 2. If the incus has to be removed in case of a more serious defect, the columella can be properly fixed to the stapes by means of glass-ionomer cement without the risk of scar-induced lateralisation. 3. The fixation of the stapes prosthesis' wire loop to the incus can be effectively achieved by glass-ionomer cement.
Operations to reconstruct defects of the ossicular chain conventionally involve the creation of a link between the malleus handle or tympanic membrane and the head of the stapes. These procedures do not produce satisfactory hearing results in a significant number of patients and must be considered unphysiological. Over the last 5 years the author has been using an alternative approach for patients with defects of the long process of the incus but an intact stapes arch in which the defect is repaired with a small cortical bone graft. Because of the way in which the graft fits over the stump of the long process it is called the 'sleeve' technique. So far 30 operations have been carried out and 21 patients have been followed for more than 1 year. The hearing results in these patients have been compared with those for patients with the same ossicular defect who have undergone conventional reconstructions by the same surgeon. There were significantly larger hearing gains (P < 0.04) and smaller postoperative air-bone gaps (P < 0.04) at 1 year in the 'sleeve' technique group. The technique is easy to perform and therefore appears to be the technique of choice in ears with partial erosion of the long process of the incus.
Keypoints * The successful use of glass-ionomeric cement in primary stapes surgery for attachment of the wire loop of the stapes prosthesis to the long process of the incus is reported. * Early hearing outcomes were similar in patients where cement was used for stapes prosthesis attachment compared with those with standard wire crimping technique. * Use of glass-ionomeric cement to attach the stapes prosthesis to the incus may prevent stapes prosthesis displacement and loosening. * This technique may decrease rates of revision stapes surgery and allow the safe use of magnetic resonance image scanning.
This report presents the results of 210 cases over a 10-year period using PORPs, TORPs, and notched incus homografts (NIH), for ossicular reconstruction in chronic ear surgery. There were 192 adults and 18 children. The surgical technique utilized temporalis fascia in an underlay technique with canal skin covering the outer surface of the fascia. Intact canal wall mastoid-tympanoplasty, as a one-stage procedure, was used for most cases. Homograft nasal cartilage was placed between the Plasti-Pore prosthesis and the graft. Notched incus homografts were prepared prior to surgery and stored in 4% formalin. There were 149 mastoid-tympanoplasties and 61 tympanoplasties performed. Revision of our cases was performed in 16.6%. Within 3 months of surgery, 86% of adults, and 44% (8/18) of children had dry, healed ears free of disease. The graft take rate was 96%. In adults, a total of 99 NIH, 50 TORPs, and 43 PORPs were implanted. In adults, the closure of the air-bone gap to 20 dB or less occurred in 58% using TORPs, 67% using PORPs, 76% using NIH-Partial replacement, and 20% using NIH-Total replacement. Excluding the cases that failed for reasons other than conductive hearing loss, the results improved to 69% for TORPs, 77% for PORPs, 77% for NIH-P, and 27% for NIH-T. In adults, the extrusion rate was 5.5% for Plasti-Pore and 3% for NIH. In children, the extrusion rate was 17% for Plasti-Pore prostheses. From this study, it appears that PORPs and TORPs with homograft nasal cartilage are satisfactory prostheses for chronic ear surgery in adults. In children, Plasti-Pore prostheses should be avoided unless the ear is healed, aerated, and stable. NIHs are good prostheses when the stapes is intact, but they are inferior to the TORP when placed on the footplate. Also, the NIH requires preparation prior to surgery and may be difficult to obtain. We plan to continue using PORPs and TORPs in chronic ear surgery until a better technique is found, or the complication rate becomes unacceptable.
Experimental incus transplants were performed in cats. The gross findings and histologic data were recorded and correlated to the use of four preservation methods for homografts (alcohol, Cialit, formalin, and freezing). The formalin preserved incudes produced the least middle ear reaction and ossicular fixation. These incudes also exhibited a uniform perivascular bone remodeling throughout the homograft while the bones preserved in Cialit and alcohol were replaced much faster and ossicular chain fixation occurred. The incus bones preserved by freezing were better tolerated than the Cialit and alcohol ones but not as well as the formalin ones.
The surfaces of immobilised incus and malleus joints were studied with the scanning electron microscope. The hyaline cartilage showed arthritic changes similar to osteoarthritic big joints of the body. A direct radiologic magnification technique could likewise demonstrate typical arthritic signs. Comparing findings from histologic studies in the literature, we could demonstrate that the intact hyaline cartilage degenerates if the ossicles are immobilised. The minimal static friction of the intact smooth joint surface is a prerequisite for its assumed role namely protection of the inner ear against hazardous pressure changes. A hypothesis is developed to the effect that the movement of the ossicles, necessary for lubrification and nutrition of the hyaline cartilage, is maintained by the two middle-ear muscles. Their function, which had not been explained so far could thus be interpreted--besides a possible effect on sound transmission--as preserving the intact joint surfaces of the ossicles. Nature seems to set great store by the importance of the middle ear joints, as shown by the development of a new joint structure in an implanted homoio-incus.
A twelve-year experience with banked homograft ossicles has developed into a system of presculptured incus allografts adapted for the correction of many ossicular defects encountered in tympanoplasty and revision stapes surgery. The standardized preparation of a number of variations of modeled incus prostheses for an operating room bank by a well-trained ear homograft laboratory technician has been an effective and time-saving technique.
The average postoperative air-bone gap after interposition of an incus between tympanic membrane and stapes footplate is too high in case of missing crura of the stapes, it is 27 dB. The interposition of an artificial prosthesis, according to Shea and beeing made of "Platipore", leads to a statistically based lower air-bone gap with a mean of 20 dB. Concerning the change of bone conduction, there is no difference between these two methods of operation. The rate of artificial prosthesis which are perforating the tympanic membrane, increases after seven months up to 15%, but only 4% of the incuses invade the plane of the tympanic membrane after 22 months.
Our clinical study proves whether or not the warning is justified not to reimplantate autologic ossicula in cholesteatoma operations in order to avoid recidives. After interposition of the autologic incus in 18 patients we found cholesteatome recidives--originating from the incus--in two cases. According to histological studies, even the most careful preparation cannot avoid that some cells of the epithelium remain on the ossicula, from which a cholesteatoma recidive may develop. Clinical studies show rather low rates of recidives compared with the histological findings. Possibly remaining squamous epithelium cells in autologic ossicles need not always cause recidives. Clinical and histological studies lead to the demand that because of the possibility of cholesteatoma recidives autologic ossicula should not be reimplated in cholesteatoma operations.
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.
In 34 posttraumatic incus dislocations, the initial sensorineural hearing loss (primary) after the trauma and that 11 years after trauma (late) were analyzed. Primary hearing loss measurements following the trauma showed that 53% of patients had sensorineural hearing loss of more than 10 dB for at least one of the frequencies from 1,000 to 4,000 cps, 18% for more than 30 dB. For late hearing loss after the trauma, the corresponding percentages were 50% and 15%, respectively. No reliable progression of the posttraumatic sensorineural hearing loss was found, although a few exceptions were seen. It may be concluded that sensorineural hearing loss is not a progressive disorder of the inner ear.
Depressions in the bone surface of the normal human incus long process are found with great frequency. This paper reviews the frequency and distribution of these depressions, discusses their histologic appearance, and speculates upon their significance. While their clinical significance is unclear, they may be related to several conditions encountered in otologic practice.