OBJECTIVETo compare the mechanical properties of point contact-dynamic compression plate (PC-DCP) and its effects on cortical bone perfusion with that of dynamic compression plates (DCP) in goat tibiae.

METHODSTwenty pairs of matched fresh goat tibiae were used. A transverse fracture model was established. The fractures with a 3mm interspace between the fracture ends were subject to fixations with the DCPs and the PC-DCPs respectively, then the four-points bending tests and the torsion tests were conducted to compare the mechanical properties of the PC-DCP with that of DCP. Another 13 sexually mature goats underwent fixations with the DCPs and the PC-DCPs, respectively, at the mid-shafts of the intact bilateral tibiae. Ischemic zones were observed at four time points (1 day, 2, 6, and 12 weeks after operation) using disulphine blue staining technique.

RESULTSThere were no significant differences in mechanical properties, such as bend- and torsion-resistance, between the DCPs and the PC-DCPs. One day, 2, and 6 weeks after operation, on the side of DCP fixation, outer cortical bone ischemia under the plate persisted, and this condition did not reverse until 12 weeks after operation. However, on the side of PC-DCP fixation, cortical bone ischemia occurred only in the periphery of the screw holes and at the contact sites of the PC NUTs 1 day after operation, and it disappeared at 2 weeks after operation.

CONCLUSIONSThe PC-DCP has similar biomechanical properties of the DCP, but is less detrimental to local bone blood circulation than the conventional plates.

Animals ; Biomechanical Phenomena ; Bone Plates ; Fracture Fixation, Internal ; instrumentation ; Goats ; Staining and Labeling ; Tibia ; blood supply ; Tibial Fractures ; physiopathology ; surgery

Objective In cerebral aneurysm clipping and embolization, blood pressure control and temporary parent artery blocking are common methods to prevent aneurysm rupture. Their influence on the prognosis is uncertain. In this study, we try to find out the association between methods above and prognostic indicators.Methods We held a retrospective analysis on patients' medical records of cerebral aneurysms surgical clipping and endovascular coiling , and recorded gender, age, diagnosis, Hunt-Hess grade, Glasgow coma scale score, treatment methods, a history of hypertension, preoperative systolic blood pressure, with or without controlled hypotension, systolic blood pressure difference before and after controlled hypotension, with or without temporary artery blocking, with or without hypertension after treated aneurysm, prognostic indicators including mortality after 1 month, intensive care unit (ICU) stay time of survivors, discharged Glasgow outcome scale (GOS) score. Prognostic indicators were regarded as dependent variable, all the factors were regarded as independent variable, and the strength analysis of influence factors on prognostic indicators was made by binary logistic regression.Results Total cases were 165, including 68 males and 97 females, with an average age of 56 (12-85) years. The mortality after 1 month was 10.9% (18 cases). The ICU stay time of survivors was 7.35 (0-67) days. GOS score at discharge was 1-3 in 40 (24.2%) patients and 4-5 in 125 (75.8%) patients. Systolic blood pressure difference before and after controlled hypotension was an independent factor influencing mortality (t=2.273, P=0.024), and the greater the difference was, the higher the mortality would be. Timely hypertension after aneurysm treated was an independent factor affecting ICU stay time of survivors and patients with hypertension had shorter ICU stay time (χ=10.017, P=0.001). Blood pressure control (χ=0.088, P=0.767) and temporary blocking (χ=1.307, P=0.253) did not show significant influence on GOS score at discharge.Conclusions Timely controlled hypertension after aneurysm clipping and embolization can significantly shorten the stay time in ICU. The degree of controlled hypotension associates with postoperative mortality, the greater systolic blood pressure difference before and after antihypertensive treatment is, the higher the mortality will be.