[Reconstruction of the superstructure of the stapes in guinea pigs with biovitro ceramic and silicone foil]. / Rekonstruktion des Steigbügeloberbaus beim Meerschweinchen mit einer Biovitrokeramik und Silikonfolie.

BACKGROUND: The reconstruction of the stapes superstructure is still a problem. Efforts for the fixation of implants on the footplate did not show satisfying results yet. METHODS: In 6 guinea pigs a biovitro ceramic (Bioverit) was placed on the stapes footplate after removal of the superstructure. The exclusive bony fixation of the implants on the footplate should be achieved by the use of silicone foils. For control purposes replantation of autologous ossicles was done in one group of 3 animals and a sham operation was performed without any use of implants in the other group of 6 guinea pigs. RESULTS: After 21 weeks not only bony fixation of the implant with the footplate was observed, but furthermore with the wall of the middle ear. Bone formation was detected along the silicone foils. In the first control group of animals we found bony fixation of the replanted ossicles and even a bow-shaped reconstruction of the stapes superstructure in the second. CONCLUSIONS: The guinea pig was not an ideal model for questions of middle ear reconstructions due to its enormous potential for bone formation. In this animal model bony fixation of glass-ceramic with the stapes-footplate could be induced.

[Bilateral bone anchored hearing aid management of children with external ear dysplasia and/or ear canal atresia]. / Beidseitige BAHA-Versorgung bei Kindern mit Ohrmuscheldysplasie und/oder Gehörgangatresie.

BACKGROUND AND OBJECTIVE: The literature gives hardly any information about the benefits for children of using a bilateral bone-anchored hearing aid (BAHA) as opposed to a bilateral conventional bone conducting hearing aid. PATIENTS AND METHODS: Within a period of 12 years, three children were selected for treatment with bilateral BAHA. At the time of surgery, the children were aged between 8 and 10 years. Two of the children suffered from Franceschetti syndrome and one child from Goldenhar's syndrome. The clinical course of these three patients is presented. RESULTS: In all cases, treatment with BAHA was beneficial according to subjective and objective criteria despite localized inflammatory complications in two of the three cases. CONCLUSIONS: The bilateral use of BAHA should be considered more frequently as an alternative to conventional bone conducting hearing aids even for children.

The value of ablating oto-rhino-laryngological (ORL) foci before haematopoietic stem cell transplantation (HSCT).

Between June 1996 and May 1997, 92 patients underwent haematopoietic stem cell transplantation (HSCT) for haematological malignancies. To participate in a prospective single-centre trial to evaluate oto-rhino-laryngological (ORL) related problems, 43 of these patients (27 male, 16 female, median age 38) signed an informed consent. A questionnaire about ORL related problems was assessed before and after HSCT. Only 21 of the patients (49%) could be fully examined after transplantation because of overall mortality and follow-up realised by other health care centres. In the deceased patients, however, a close review of the patients' notes was carried out. An ORL focus was not identified as the cause of death in any of the deceased. Pre-transplant examination revealed 15 patients with ORL relevant infectious foci. To make urgent HSCT possible, surgical pre-transplant ablation of chronic ORL infection sites took place in four patients only. In this cohort, pre-transplant ORL pathology was not amplified after HSCT. None of the 11 patients presenting ORL foci before transplantation experienced enhancement of ORL disease. These data suggest that the indication for surgical intervention with regards to ORL infection prior to HSCT should be regarded cautiously. However, the potential risk of dissemination of a pre-existing fungal infection from an ORL site should be considered and treated on a case-by-case basis.

Experimental results concerning the reconstruction of the stapes superstructure with bioactive ceramics.

We examined the feasibility of rebuilding a stable stapes superstructure in the middle ear for a new articulated ossicular chain by using bioactive ceramic and glass ceramic in guinea pigs. The ceramic implants were placed on the stapes footplate without touching the tympanic membrane, thus protecting it against relative movements. The implants were removed together with the stapes footplate after six weeks, three and six months respectively. After six weeks, histological evidence of bony connections between all ceramic implants and the remnants of the crurae were found, being more pronounced after three and six months. We propose a new implant for the reconstruction of the stapes superstructure.

[Reconstruction of the stapes superstructure with bioactive ceramics]. / Stapesoberbauerekonstruktion mit bioaktiven Keramiken.

In this study we examined the feasibility of rebuilding a stable stapes superstructure for a new articulated ossicular chain by using bioactive ceramics. Dense hydroxylapatite and ceravital were tested in guinea pigs. The ceramic prosthesis was placed on the remnants of the footplate to create a bony connection without touching the tympanic membrane, thereby protecting it from relative movements. The implants were explanted together with the stapes footplate at six weeks and three months, respectively. Histologically, bony connections were found between all ceramic implants and the remnants of the crura even at six weeks and became more pronounced after three months.