ABSTRACT
Objective With the isocentric C-arm (Iso-C) three-dimensional computerized navigation system,cadaveric pelvic specimens were used to imitate double screw fixation of the symphysis pubic.Practicability and safety of the screw trajectory were examined postoperatively by local cadaveric dissections and imaging tests.Methods Pelvic specimens were harvested from 8 male and 7 female adult cadavers.Double screw placement in symphysis pubic was performed using the Iso-C three-dimensional navigation and entry point and safety trajectory was achieved.With the detailed local dissection postoperatively,distances from screw entry and exit points to unilateral structures (spermatic cord,femoral artery and vein,femoral nerve,obturator artery and vein,obtrurator nerve,and so on) were measured respectively.After complete removal of surrounding soft tissues of the specimen with only bony structure kept,the entry angle and length were calculated.Accuracy of double screw fixation of symphysis pubic was further checked using X-ray and CT.Results Entry point of the first screw was at the junction of unilateral pubic tubercle and transitional site of superior pubic ramus.Mean angle of the first screw with the horizontal plane was (7.7 ± 1.9) ° in men and (8.1 ± 1.7) ° in women.Mean angle between the first screw and coronal plane was (7.8 ± 1.8)° in men and (7.7 ±2.0)° in women.Entry point of the second screw was in the same place in the contralateral pubic tubercle.Mean angle between the second screw and horizontal plane was (30.6 ± 4.0) ° in men and (30.8 ± 3.4) ° in women.Mean angle between the second screw and coronal plane was (9.1 ± 3.0)°in men and (9.2 ± 3.3)°in women.Conclusions With the three-dimensional computerized navigation system,the bony channels of double screws implanted in the symphysis pubic are achieved and reliable.Percutaneous double screw fixation is feasible to treat the pubic symphysis diastasis.
ABSTRACT
Objective To perform anatomic study on percutaneous cannulated-screw fixation of symphysis pubis diastasis in human cadaveric pelvic specimens so as to provide a basis for clinical practice of the technique.Methods Fifteen adult pelvic cadaveric specimens were dissected to expose pubic symphysis,peripheral major vascular nerve,spermatic cord and round ligament of the uterus.Thickness of pubic symphysis and distance between the outer edge of pubic tubercle and spermatic funicle or round ligament of uterus were measured respectively.Distances were measured respectively from entry and exit points to the above-mentioned structures in the direction of guide pin.Entry depth and angles of guide pin with the coronal plane and cross section of the human body were measured.Surgery was simulated to prove the surgery effect through post-surgery filming and CT.Results Thickness of symphysis pubis was gradually reduced from up to down.Pubic tubercle part was the most thick and it could accommodate a 7.3 mm cannulated-screw.Entry and exit points of cannulated-screw were in certain distances with the important nervusvascularis and spematicfunicle (or round ligament of uterus) in the periphery,which were invulnerable to damages in the process of surgery.Proper lengths of cannulated screws were (73.6 ± 1.3) mm for males and (72.4 ± 1.7)mm for females (t =3.146,P ＜ 0.05).Screw thread was completely embedded in pubic tubercle.Angles of guide pin with coronal plane and cross section of human body were (7.3 ± 1.1) °and (6.4 ± 1.0) ° for males (6.9 ± 1.5) ° and (6.1 ± 0.6) ° for females.Radiography and CT findings confirmed that all pin tracks were in the bone substances with angle and length of screws staying within the scope of experiment.Conclusion Percutaneous cannulated screw fixation is reliable and safe for symphysis pubis diastasis.
ABSTRACT
Objective Study the relationship between type A influenza virus genetic variation with survival selective pressure, help for the finding of possible vaccine conserved antigen target. Methods Select seven strains of same HA (Hemagglutinin) serotype, regional and isolation time closely related type A influenza virus with full HA gene coding sequence; use Blast2 program to calculate the parameter of nucleotide conservative, amino acid conservative, mutation ratio of codon 3rd (over) non 3rd locus, survival selective pressure indicator of these virus strains; analysis the parameters relationship with survival selective pressure indicator. Results Nucleotide conservative of HA gene is significantly lower than that of other genes; amino acid conservative of HA gene is similar with NS gene, all lower than that of other genes; genetic variation of HA gene is under survival selective pressure; selective pressure toward NS, PB1 gene is relatively lower than that toward NA, NP gene; survival selective pressure indicator is strongly correlated with mutation frequency upon codon 3rd locus. Conclusions Genetic variation of influenza virus is determined both by mechanism of relax replication model and survival selective pressure; genetic conservative of each gene is different, NA, NP gene could be selected as possible vaccine target for their relative high conservative, HA gene possesses medium genetic conservative with prospective of finding more conserved epitope region within its full sequence, NS, PB1 are not recommended as vaccine candidate for their relative low genetic conservative.