Biomedical subjects

J Lindström

Publications and source records attributed to J Lindström.

95 records · Page 6Linked to original sources

PubMedDate not supplied

A clinical pilot study on preformed autologous ossicles. II.

A research project concerning performed autologous ossicles has been going on for more than ten years. Animal experimental studies were followed by a clinical pilot study which showed that bone could be produced in a titanium mould placed in the proximal tibia metaphysis. In the present investigation, in which another five patients were operated on, the experimental design was changed compared to the first pilot study and bone production was improved. In addition to the tibial moulds ten titanium cylinders were placed around a bony bridge prepared in the linea temporalis of the ear to be reconstructed. Nine out of ten of these cylinders contained bone suitable for ossiculoplasty. Histology showed higher osteocyte density and a higher proportion of vital looking osteocytes in the performed grafts compared with a peroperatively sculptured graft of cortical bone. On histochemical investigation the performed graft cells seemed viable at the time of transplantation. The technique for obtaining a preformed autologous ossicle through the titanium cylinders in the temporal bone was easy to perform and the patients did not experience any discomfort. The risk of infection in this area was judged to be small.

Adult↗

PubMedDate not supplied

A clinical pilot study on preformed autologous ossicles. I.

The study is part of a project aimed at obtaining an autologous, preformed transplant for reconstruction of a defect ossicular chain. In animal experiments we found that bone could be produced in a titanium mould placed in the tibia of the rabbit and dog. To find out whether this observation was applicable in man, 5 patients with ossicular defects were selected. A titanium mould containing two chambers was placed in the proximal tibial metaphysis for 6 months. When the moulds were extracted bone was found in 7 of the 10 chambers. In 2 of these the bone was stable and suitable for ossiculoplasty. On histological examination the same picture as in the animal experiments was found, an outer layer of cortical bone surrounding a system of spongy bone with marrow and haematopoietic cells. Microradiological examination verified the presence of mineralized bone tissue.

Adult↗

PubMedDate not supplied

Analysis of the mechanical impedance of bone-anchored hearing aids.

Some patients who need hearing aids are unable to use an apparatus which transmits the sound via the external ear canal and have to use a bone conduction hearing aid. The bone vibration transducer of this aid is applied to the skin over the mastoid process and the sound is transmitted via the soft tissue and bone to the cochlea. The pressure needed to apply the transducer often gives the patient discomfort and the damping effect of the soft tissue gives poor quality of the sound transmitted. Advances in the ability to permanently implant foreign material in the body and perform permanent skin penetration has made it possible to develop a bone-anchored hearing aid. Fourteen patients have been equipped with such hearing aids. To be able to give these patients the best hearing aid, a new transducer has to be constructed to match the new situation. The impedance of the bone-anchored titaniumscrew/skull has been studied and the resistance and reactance of the mechanical impedance have been measured. The influence of a damping soft tissue layer over the bone has been analyzed. The difference between the impedance of the skull and the impedance of the soft tissue + skull was in the order of 10 to 25 dB depending on the frequency.

Acoustic Impedance Tests↗

PubMedDate not supplied

Active phenoxymethylpenicillin (pcV) in the mucous membranes of the oral bucca and maxillary sinus and in diffusion chambers implanted in rabbits. A methodological study.

The intention of prescribing antibiotic treatment must be to achieve a concentration of the agent within the infected tissue well above th MIC or the bacteria causing the infection. As a basis for further clinical studies on antibiotic concentrations in maxillary sinus mucosa in humans, determinations of biologically active penicillin V in the mucous membranes of the maxillary sinus and the buccal mucose as well as in tissue fluids and tissue from subcutaneously implanted tissue cages in rabbits were made. Several experimental conditions were studied, with the purpose of establishing optimal conditions with regard to tissue sampling, blood contamination, prediffusion time, etc. Penicillin V was shown to have a good penetration into mucosal tissue in the rabbit, even at low perfusion pressure.

Animals↗

PubMedDate not supplied

Five-year experience with skin-penetrating bone-anchored implants in the temporal bone.

A method for stable integration of titanium-implants in bone tissue has been developed at the University of Gothenburg, Sweden. Screw shaped implants have been inserted in the temporal bone using a delicate surgical technique. After healing-in of the implants it is, in a later séance, possible to penetrate the skin to establish a reaction-free percutaneous passage. An up to 5-year clinical follow-up has shown the possibilities of this new method in the treatment of patients with e.g. certain hearing disorders or facial defects after tumour surgery.

Follow-Up Studies↗