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Biomedical subjects

S M Perren

Publications and source records attributed to S M Perren.

At least 145 records · Page 8Linked to original sources
PubMed1979

[Vaccination against staphylococcal infections in animal experiments].

Based on favour and clinical observations we have undertaken to observe the effect of vaccination against staphylococcic infection in the mouse. A standard amount of staphylococcus was used together with a metal implant. After two weeks in the control group always an infection could be observed, and germs could be cultivated. In the groups with staphypan and in the groups with vaccinated specific vaccinia a less strong infection was observed, while a vaccinia made from salmonella typhimurium and diphtheria-toxoid showed the strongest effect. The use of unspecific vaccinia deserves further attention in relation to operations which can be made after vaccination of the patient.

Animals↗
PubMed1979

[Inclined plate screws - in vitro measurement of the stability of transverse osteotomy of tibia].

A compression plate which is exactly contoured to the bone surface produces asymmetric compression: only part of the cortex near the plate is compressed. Therefore a compression plate is not meant to be used selfstanding, it will rather be combined with additional means. Two of these have been studied: the increased stability provided by the use of lagging, inclined plate screws was compared to the one provided by the spring effect of a plate prebent for central elevation. 7-hole dynamic compression plates (DCP) and 4.5 mm cortex screws were used to stabilize transverse osteotomies in human tibiae in vitro. Flexural and torsional testing revealed that the use of an inclined lag screw or a prebent plate increases stability compared to the one achieved with an exactly contoured plate alone. Preliminary tests suggest, that a combination of plate lag-screw and prebending offers stability up to high loads.

Biomechanical Phenomena↗
PubMed1979

[Importance of the friction between plate and bone in the anchoring of plates for osteosynthesis. Determination of the coefficient of metal-bone friction in animal in vivo].

In mechanical devices in general the friction plays an important role in force transmission. To find out about the magnitude of frictional forces between internal fixation plate and bone in vivo, simultaneous strain recording in plated bone and instrumented plate were performed. After 3 weeks of implantation the torque applied to a single plate-screw was set to definite levels. Thus it could be determined at what level of screw compression and at what tangential load of the related surface bone-plate, gliding occurred. The coefficient of friction was found to be 0.2 +/- 0.09 (x +/- Sx). It can be concluded that in vivo friction produced at the plate-bone contact surface is able to guarantee stability of fixation.

Animals↗
PubMed1979

[A method of quantitative determination of tissue tolerance in decreased relative movement between implant and tissue].

A method of testing in vivo tissue tolerance to different implant materials is presented. It aims at reduction of variance due to mechanical irritation at the tissue-implant interface through the use of cylindrical implants with grooves. The special type of histological preparation which is necessary and problems encountered when using these techniques are described. The numerical evaluation of round cells and foreign body giant cells seems to give uniform results with low variance, which could be of interest for standard testing of material.

Animals↗
PubMed1977

Behavior of cortical bone grafts under different types of fixation.

The fate of cortical bone grafts, rigidly fixed by means of a special metal splint, was studied in rabbits. Cortical grafts of fresh autologous bone were compared with dry-stored allogenous transplants frozen to -20 degrees C. To study the incorporation and remodeling, fluorochrome labeling and microradiography were used. The main parameters of remodeling were the quantities of old lamellar bone, newly formed lamellar bone, and vascular spaces present in the transplant areas. The data obtained are compared with the results of a previous similar study of grafts, which were fixed by Mersilene sutures. Fresh autologous as well as allogenous (dry-stored, frozen to -20 degrees C) cortical bone grafts, used as free transplants, show the same type of incorporation and ultimately the same amount of remodeling. Rigid fixation is a valuable contribution in promoting primary function.

Animals↗