Evaluation of different screw fixation techniques and screw diameters in sagittal split ramus osteotomy: finite element analysis method.

Sagittal split ramus osteotomy (SSRO) is used for correction of numerous congenital or acquired deformities in facial region. Several techniques have been developed and used to maintain fixation and stabilisation following SSRO application. In this study, the effects of the insertion formations of the bicortical different sized screws to the stresses generated by forces were studied. Three-dimensional finite elements analysis (FEA) and static linear analysis methods were used to investigate difference which would occur in terms of forces effecting onto the screws and transmitted to bone between different application areas. No significant difference was found between 1·5- and 2-mm screws used in SSRO fixation. Besides, it was found that 'inverted L' application was more successful compared to the others and that was followed by 'L' and 'linear' formations which showed close rates to each other. Few studies have investigated the effect of thickness and application areas of bicortical screws. This study was performed on both advanced and regressed jaws positions.

Complement (C3, C4) and C-reactive protein responses to cardiopulmonary bypass and protamine administration.

Complement activation has been deemed responsible for the damaging effects of cardiopulmonary bypass (CPB) in patients undergoing open heart surgery. We studied C3, C4 and C-reactive protein (CRP) in 22 patients undergoing CPB. In Group 1 (11 patients), protamine was given intravenously and in Group 2 (11 patients), via the aortic root after CPB. Significant decreases were observed in C3 and C4 during CPB in both groups indicating complement activation primarily by the classic pathway. Protamine did not lead to further activation of the complement system. In both groups, C3 levels gradually returned toward baseline within 24 hours but C4 levels were still lower than baseline 24 hours postoperatively. CPB and protamine administration did not cause any significant changes in CRP levels, but CRP increased abruptly 24 hours after operation. Although activation of complement system during CPB is expected to invoke an acute phase response, we conclude that this period is not long enough to induce an increased production of CRP in response to tissue injury or inflammation.