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Biomedical subjects

A Tjellström

Publications and source records attributed to A Tjellström.

At least 19 recordsLinked to original sources
PubMed1995

Immunohistochemical study of the soft tissue around long-term skin-penetrating titanium implants.

Bone-anchored percutaneous titanium implants have become a well-established clinical procedure with a low incidence of adverse reactions. However, passage through the skin leads to a breach in the barrier to exogenous pathogens. In the present study, monoclonal antibodies were used to investigate the distribution of lymphocyte subpopulations in the soft tissue around such implants. Eight biopsies from patients with clinically irritated skin, five from non-irritated and eight from skin without skin-penetrating implants were analysed. The number of immune cells was increased in the group of patients with skin penetration compared with patients without skin penetration. In the group with clinical irritation there was an increased level of B-lymphocytes compared with those without irritation. The data suggest that there is an immunological compensation for the mechanical loss in barrier function at these implants and that an antibody-mediated response is present at clinical signs of irritation.

Adolescent↗
PubMed1995

Electron microscopic observations on the soft tissue around clinical long-term percutaneous titanium implants.

Percutaneous implants of titanium ad modum Brånemark have been in clinical use in the head and neck since 1977. The incidence of adverse reactions is low. In a previous study we have demonstrated the presence of inflammatory cells in the subcutaneous connective tissue surrounding the implants and this increased exposure to exogenous antigens was suggested to be compensated by a barrier of inflammatory cells in the soft tissue. To get further information on the nature of the tissue-implant contact, in the present study we have examined the structure of the tissue close to the percutaneous implant using transmission electron microscopy. We could not see evidence for an attachment of the epithelium to the implant, nor between the connective tissue and the implant. Retrieved implants were also analysed and we did not find any organized tissue remaining on the implants.

Adult↗
PubMed1995

One-stage procedure to establish osseointegration: a zero to five years follow-up report.

A cohort of 214 patients, who were operated on to insert implants in the mastoid process for the retention of bone-anchored hearing aids and auricular prostheses, was follow-up over a five-year period. About half the group were operated on using the conventional two-stage procedure allowing three to four months for osseointegration. In the second group (one-stage group) the skin penetrating coupling was connected at the time of the implant insertion. The success rate for stable implants was found to be the same in both groups. In the one-stage group four out of 161 implants inserted were lost and in the two-stage group three out of 120. The cumulative success rate was also found to be the same. A 'worst case' table where patients lost to follow-up, patients who died during the study period, and patients who for some reason left the study is also included. The importance of this 'worst case' scenario when follow-up data are presented is discussed.

Adolescent↗
PubMed1995

The bone-anchored hearing aid. Design principles, indications, and long-term clinical results.

This article presents a summary of design principles, indications, and clinical results obtained with the bone-anchored hearing aid (BAHA). Hearing through bone conduction and mechanical stimulation of the skull with percutaneous versus transcutaneous excitation and the functional capability of the ear level BAHA sound processor is presented. Moreover, the surgical procedure is described and the success rate to establish and maintain osseointegration is presented together with the frequency of skin reactions at the implant site. The audiologic and questionnaire results achieved with the BAHA is also presented and discussed.

Adult↗
PubMed1994

Resonance frequencies of the human skull in vivo.

Patients with skin penetrating titanium implants in the temporal bone, for attachment of bone-anchored hearing aids, have made it possible to investigate the free-damped natural frequencies (resonance frequencies) of the human skull in vivo. The resonance frequencies of the skull of six subjects were investigated. Teh resonance frequencies were extracted from two frequency response functions (acceleration/force) measured on each subject: One point measurement where the force and acceleration were both measured at the same point, and one transcranial measurement where the acceleration was measured contralaterally. Between 14 and 19 resonance frequencies were identified for each subject in the frequency range 500 Hz to 7.5 kHz. The two lowest resonance frequencies were found to be on the average 972 (range 828-1164) and 1230 (range 981-1417) Hz. The relative damping coefficients of all resonances were found to be between 2.6 and 8.9%. Due to the relatively high damping coefficients, it is assumed that the resonance frequencies do not significantly affect bone conducted sound. In the transcranial measurements, however, a few large antiresonances were found which may affect bone-conducted sound. Intersubject variations were large, probably due to individual variations in skull geometry and in mechanical parameters. The results were shown to be consistent with previous results obtained on dry skulls. No obvious correlation between lowest resonance frequency and skull size was found.

Adult↗
PubMed1994

Persistent irritation of the soft tissue around an osseointegrated titanium implant. Case report.

Percutaneous implants for hearing aids which are anchored in the bone have a low incidence of skin irritation. We report here the case of a man born in 1958 who had a long period of skin irritation, which was on two occasions associated with bacterial infection with Staphylococcus aureus. Despite local treatment with steroid/antibiotic ointment and skin grafts, episodes of skin irritation recurred, often in association with a relapse of ear drainage. Tests of delayed hypersensitivity to the implant and standard allergens were negative. Morphological and immunohistochemical analysis of the skin after removal of the abutment revealed an intense inflammatory reaction, with polymorphonuclear leucocytes, macrophages, lymphocytes, and HLA-DR expressing cells. In contrast to the inflammatory reaction in the soft tissue, there was a large amount of bone and the degree of bone-implant contact was good.

Adult↗
PubMed1994

The bone-anchored hearing aid: principal design and audiometric results.

The principle of the bone-anchored hearing aid (BAHA) is simple: sound vibrations are directly transmitted to the skull bone via a skin-penetrating titanium implant, and then are further transmitted to the cochlea, bypassing the middle ear. The present paper summarized the audiometric results from 122 patients with an average follow-up time of 5.6 years. When herein-suggested indications for treatment with the bone-anchored sound processor HC 300 are followed, the success rate is very high. The improved quality of life reported by the patients is a combination of improved quality of sound (warble tone threshold, speech reception threshold, and discrimination in noise), improved comfort, and relief from middle ear and ear canal disease occasioned by conventional hearing aids.

Audiometry↗
PubMed1994

Long-term follow-up with the bone-anchored hearing aid: a review of the first 100 patients between 1977 and 1985.

Skin-penetrating implants have been used since 1977 for retention of Bone Anchored Hearing Aids, or BAHA. This paper analyzes the stability of the implants and the frequency of skin reactions in the first one hundred consecutive patients operated upon at Sahlgrens Hospital, Göteborg. The follow-up time varied between 8 and 16 years. Ninety percent of the implants were found to be stable. Five percent were explanted due to direct trauma. Another five percent lost integration but often after many years in use. Adverse skin reactions were seen, but 79% of the patients had no or one single episode of soft tissue reaction. A percutaneous coupling in the mastoid process will give rise to only minor clinical problems and could be considered as a simple, predictable and safe device.

Adult↗
PubMed1993

The bone-anchored hearing aid and bone-anchored epithesis for congenital ear malformations.

Surgery for correction of aural atresia was performed on 156 ears in 111 patients. A comparison was made between plastic surgery for auricular reconstruction and the bone-anchored epithesis. Another comparison was performed between hearing improvement after reconstructive surgery for meatal and middle ear atresia and the bone-anchored hearing aid. It was found that the bone-anchored epithesis is an excellent alternative to plastic reconstructive surgery of the auricle. The bone-anchored hearing aid could be considered as a strong alternative to surgery in patients with meatal and middle ear atresia--especially in patients with advanced malformations. Neither the bone-anchored epithesis nor the bone-anchored hearing aid excludes the patient from reconstructive surgery later in life.

Adolescent↗
PubMed1993

Postimplantation irradiation for head and neck cancer treatment.

Eleven patients who had undergone surgical treatment for head and neck cancer and had titanium implants placed for skin-penetrating prostheses were irradiated postimplantation. The absorbed doses of irradiation to the implant region varied between 50 and 80 Gy. The time interval between implant surgery and irradiation varied from 4 to 60 months. Of 32 fixtures placed, 2 were removed as part of extended tumor surgery and 2 were lost in conjunction with induced chemotherapy. Five of the patients showed skin dehiscences around 9 implants after completed irradiation. Osteoradionecrosis developed in three of the patients after radiotherapy. If irradiation is to be performed in areas where titanium implants have been placed, it is recommended that all prostheses, frameworks, and abutments be removed before irradiation; the fixtures should be allowed to remain intact but should be covered with skin or mucosa.

Adolescent↗
PubMed1993

Craniofacial osseointegration: the Canadian experience.

A survey was undertaken to determine the number of centers in Canada with an active involvement in extraoral osseointegration. It was found that six centers had placed 222 implants in 91 patients in Canada. The individual implant success rates for the Canadian experience were compared with the published Swedish and United States' experience. The Canadian experience is combined with the Swedish and United States' experience to provide retrospective multinational multicenter data. The data given should be viewed as providing trends only and not as definitive expectations of predictable success rates. The success rates are considered likely to change with time as the number of patients treated increases and the duration of follow-up is extended. The mastoid region in nonradiated patients is considered to provide a high degree of predictable individual implant success. The success rates in radiated patients yield far lower success rates, which vary with anatomic location. The criteria for success in using craniofacial implants need to be defined and should reflect the differences between extraoral and intraoral implants.

Canada↗
PubMed1992

Tissue-integrated implants in children.

The aim of this study is to present our clinical experience with tissue-integrated extra-oral implants in children. Thirty consecutive cases of children with a total of 59 standard titanium fixtures inserted in the temporal bones and used as bone-anchorage for auricular epistheses (14 cases) and hearing aids (16 cases) were studied. The surgical procedure is performed in two steps and involves an extremely gentle handling of the soft tissue and bone. The patients were followed with regular check-ups for an average of 40 months after hearing aid/prosthesis fitting. The fixture survival rate was 96.6% for the whole group. The hearing aids had a reaction-free skin penetration in 91.67% of the postoperative observations and the prostheses had a reaction-free skin penetration in 75.00% of the postoperative observations. It is concluded that the use of 'osseointegrated', implants in carefully selected cases, in children, appears to be a reliable method for bone anchorage of epistheses and bone conduction hearing aids. A close follow-up and control of this patient category is especially important with respect to the long-term results.

Adolescent↗
PubMed1992

An evaluation of auricular prosthesis using osseointegrated implants.

The purpose of this evaluation is to compare whether retention of auricular prostheses, through utilization of osseointegrated implants rather than by adhesive, provides any improvement in patient acceptance and prosthesis longevity. Forty-seven out of a total of 49 patients having facial prostheses, retained by means of Brånemark fixtures, were surveyed. Ease of retention was noted in 91% of the patients. Satisfaction with the shape of the prosthesis, colour and ease of positioning was 100, 85 and 98% respectively. None of the patients experienced skin irritation under the prosthesis and 94% of them wore their prosthesis daily. Of the 13 patients with previous prosthesis experience, 92% stated improved retention and all of them found ease of positioning and wearing comfort had improved. Durability was better in 62%, unchanged in 23% and worse in 15% of these 13 patients.

Adolescent↗
PubMed1992

Clinical, immunological and bacteriological evaluation of adverse reactions to skin-penetrating titanium implants in the head and neck region.

Between 1977 and October 1989, 445 patients have been treated with bone-anchored skin-penetrating titanium implants for anchorage of facial prostheses or bone-conducting hearing aids, at the Ear, Nose and Throat Department at Sahlgren's Hospital in Gothenburg. The majority of patients had no adverse skin reactions, while a few patients were responsible for the majority of the adverse reactions. The aim of our study was to analyse differences between these groups. We started a clinical study on 9 patients with a clinical history of adverse skin reactions around the titanium implants and 9 patients without adverse skin reactions were used as controls. None of the patients had delayed hypersensitivity to titanium. Microbiological analyses showed that when there was clinical irritation, Staphylococcus aureus could be isolated.

Adolescent↗
PubMed1992

[Osseointegrated implants in facial prosthesis and hearing aids].

The principles of osseointegration defined by Branemark are reviewed. The authors describe the otological applications of titanium implants: bone anchorage hearing aids (B.A.H.A.) and ear epitheses. Obtaining good results depends on the selection of the patients and the observance of a rigorous technique.

Ear, External↗
PubMed1992

Titanium implants in irradiated tissue: benefits from hyperbaric oxygen.

Since the introduction of osseointegrated titanium implants for bone-anchored facial and dental prostheses, an increasing number of irradiated patients are being treated with this technique. Although the number of patients who have had titanium implants after irradiation is limited, available statistics point to a tendency of a higher implant loss frequency as compared with nonirradiated patients. This review discusses factors behind deleterious tissue effects and implant failures from irradiation and points to possibilities to improve the surgical outcome with special reference to hyperbaric oxygen therapy.

Animals↗
PubMed1992

Ear deformities in mandibulofacial dysostosis.

Bilateral conductive deafness is common in mandibulofacial dysostosis with or without atresia of the external auditory meatus. This deafness is due to a wide range of deformities of the ossicular chain associated with a characteristic reduction in the size of the middle ear cavity. The inner ear is only occasionally affected. This study describes findings of experimentally induced malformations of the ears in laboratory animals which are compared to the clinical, radiological and surgical findings from 14 patients with mandibulofacial dysostosis (Treacher-Collins syndrome).

Abnormalities, Drug-Induced↗