ABSTRACT
BACKGROUND: Fracture fixation and surgical procedures have a very important impact on the final outcome of fracture healing, but the adverse outcome of fracture healing is the result of the combined action of surgical procedures and a series of four-dimensional space events. OBJECTIVE: To explore the four-dimensional space events in fracture healing. METHODS: China National Knowledge Infrastructure and Medline were retrieved, with the key words of “fracture healing, femoral fracture, stress shielding, fracture and blood flow” in Chinese and English. Retrieval of relatively macroscopic factual descriptions corresponds to the four-dimensional space events of fracture healing process, including logically supported and refuted evidence. Combined with literature review, the main four-dimensional space events after fracture fixation were analyzed. RESULTS AND CONCLUSION: The main four-dimensional space events after fracture fixation include blood flow tides, mechanical and biological impulses, grinding disc effect of small gap in hard tissue, stress shielding effect and four-dimensional space drift effect of internal fixation material. Fractures and surgical trauma are accompanied by months of super-compensatory blood flow tides, so there is no ischemia in the macro-level after fracture surgery, but the grinding disc effect will occur in the small gap of hard tissue under unstable condition, resulting in contusion injury and micro-ischemia in the fracture gap. Stress shielding effect caused by too strong fixation is an important reason for refracture after internal fixation removal and bone atrophy and thinning after internal fixation. The small axial drift of plate fixation screw may have important theoretical significance. It has “intelligent” axial dynamic effect, which can make the stress shared by plate gradually decrease with the healing of fracture. Discussing the four-dimensional space events of fracture healing will provide basic logic for the regulation of fracture healing and distraction osteogenesis.
ABSTRACT
Objective To investigate whether ultrasonic coupling agent (UCA)can produce shielding or antago-nistic effect on iodine disinfectant for preoperative skin disinfection.Methods Shielding or antagonistic effect of UCA on iodine disinfectant were detected by laboratory carrier immersion killing test and on-the-spot skin disinfec-tion test.Results Antagonistic effect:after the mixing of iodophor with UCA,the average killing rate of iodophor containing available iodine 2 500mg/L and 625 mg/L to Staphylococcus aureus decreased from 100.00% to 99.67%-99.78% and 96.85 % - 98.25 %,respectively;the average killing rate to Escherichia coli decreased from 100.00% to 99.71 %-99.82% and 95 .93 %-98.56%,respectively.Shielding effect:after smearing with UCA, the average killing rate of iodophor and iodine tincture + alcohol to Escherichia coli decreased from 100.00% to 30.76% and 100.00% to 94.48%,respectively;the average killing rate to Staphylococcus aureus decreased from 99.99% to 55 .55 % and 100.00% to 98.22%,respectively.On-the-spot skin disinfection test:the killing rate of io-dophor and iodine tincture +alcohol to natural bacteria on skin surface were both 99.99%,after skin was smeared with UCA,the killing rate decreased to 92.62% and 93 .57%,respectively.Conclusion UCA remained on the oper-ative field has shielding and antagonistic effect on iodine disinfectant.
ABSTRACT
Fletcher-Suit colpostat has an internal structure to reduce dose to bladder and rectum. Some programs were developed to calculate dose at any point in water in three dimension around the colpostat containing Cs-137 tube, to find the shielding effect to dose by the internal structure, and to draw isodose cuties and iso-shielding effect cuties. Computer was an IBM compatible AT with EGA card and language was MS-Basic V6.0. Material, shape and geometry of the structure, tube and colpostat were considered in algorithm for calculation of dose. Dose rates per unit mg. Ra. eq. in water calculated by a program were stored in auxiliary memory devices and retrieved in another programs. Isodose curves on medial side shrieked. Dose distribution was not symmetric about a transverse axis bisecting the colpostat. Reduction of dose was more excessive on top side than on bottom. Iso-shielding effect cutie showed that the shielding effect was higher on top side than on bottom, and that there was shielding effect over almost all area of medial side. Such results were related to both shifted position of tribe in the colpostat and asymmetric distribution of active source in the tube. Maximum of shielding effect was 49% on top side and 44% on bottom side. The direction of iso-shielding effect curve was generally radial from the center of active source. In treatment planning using Fletcher-Suit colpostat, the internal structure should be considered to find precise doses to bladder and rectum, etc.