Objective To biomechanically study the fixation stability of different numbers and shapes of the titanium miniplates (L-shaped and straight four-hole miniplates) in the treatment of maxillary LeFortⅠ fracture by using three-dimensional finite element method so as to provide reference for clinical treatment of the fractures. Methods Three-dimensional finite element model of maxillary LeFortⅠ fracture was established with four kinds of rigid internal fixation (RIF) methods to calculate the stress of the maxilla and the RIF as well as the displacement of the fracture segment under three kinds of occlusion.Then, the fixation stability of different methods was compared. Results Under the same occlusion condition, the decreasing order of the displacement of the fracture segment was the L-shaped plate fixation at both buttress of the maxillary and nasal maxillary zygomatic, the straight four-hole miniplates fixation at both buttress of the maxillary and nasal maxillary zygomatic, the L-shaped plate fixation at the zygomatic maxillary buttress and the L-shaped plate fixation at naso-maxillary buttress. Under the same fixation method, the decreasing order of the displacement of the fracture segment was molar occlusion, premolar oeclusion and incisor occlusion. Conclusions The fixation stability of the L-shaped plate fixation is better than the straight four-hole miniplate fixation for the treatment of LeFortⅠ fracture. Fixation at the zygomaticmaxillary buttress is better than at the naso-maxillary buttress. Use of only two miniplates to fix the LeFort Ⅰ fracture may not be stable. Molar occlusion is not good for fracture healing.

Objective To investigate the mechanism of kuiyusan on recovering intestinal mucosa of patients with active ulcerative colitis(UC). Methods Forty-eight patients with active UC were selected as our subjects. They were applied kuiyusan to retention enema for1 time per day for 15 days as a treatment course. Next treatment course were started interval 7 days and all patients were received 3 treatment courses. Changes of pathological signs were observed before and after the treatment with kuiyusan. Results The rate of intestinal mucosal focal small hemorrhages after treatment was 37. 5 %(18 / 48),significantly lower than that at pre-treatment(87. 5%(42 / 48);χ2 = 25. 60,P < 0. 001). The UC mucosal epithelial regeneration rate,disappear rate of intestinal mucosal epithelial goblet cells and Paneth cells regeneration rate at pre-treatment were 18. 8%(9 / 48),31. 2%(15 / 48),6. 3%(3 / 48),significantly different from that after treatment(50. 0%(24 / 48), 6. 3%( 3 / 48 ),20. 8%( 10 / 48 );χ2 = 10. 39,9. 85,4. 36;P < 0. 01 ). The incidence rate of intestinal lymphocyte hyperplasia and infiltration of eosinophils at pre-treatment were 95. 8%(46 / 48)and 100%(48 /48),higher than that after treatment( 72. 9%( 35 / 48 ) and 56. 2%( 27 / 48 )) and the differences were significant(χ2 = 9. 56,26. 88;P < 0. 01). Crypt abscess incidence were decreased from 56%(27 / 48)at pre-treatment to 25%(12 / 48)at after treatment( χ2 = 9. 72,P < 0. 01). Conclusion Kuiyusan can obviously improve small vascular lesions and crypt abscess of the mucous membrane on active UC,reduce neutrophil, eosinophil infiltration,maintain the intestinal epithelial tight junction,improve mucosal barrier,as well as promote healing of mucosal inflammation.

Causal inference research is a causal test designed to assess the impact of exposures on outcomes.Both experimental and observational studies can be used to examine causal associations between exposure factors and outcomes. Experimental studies are sometimes limited by factors such as ethics or experimental conditions. Observational studies account for a large proportion in clinical studies, but the effectiveness and research value of observational studies will be affected if the design of observational studies is not rigorous and the confounding factors are not well controlled.The Guidelines for controlling confounding factors and reporting results in causal inference studie formulated by a special group of 47 editors from 35 journals from all over the world provide good guidance to researchers. This article interprets the guidelines and hopes to provide help for clinical researchers.

Objective:To investigate the occurrence and influencing factors of perioperative complications after robotic gynecologic surgery.Methods:The clinical data and occurrence of perioperative complications in 1 000 cases robotic surgery completed in the First Affiliated Hospital of Zhengzhou University were retrospectively analyzed.Results:(1) Clinical data: the average age of the patients was (50.2±10.4) years old, and the average body mass index (BMI) was (24.4±3.6) kg/m 2. Among 1 000 cases, 811 cases of them were malignant tumors, including 405 cases of cervical cancer, 279 cases of endometrial carcinoma, 112 cases of epithelial ovarian cancer (EOC), 15 cases of vulvar cancer; 189 cases of them were benign diseases, including 43 cases of uterine prolapse, 57 cases hysterectomy of uterine leiomyoma and adenomyosis of the uterus ≥12 weeks, 84 cases myomectomy of uterine leiomyoma, and 5 cases of fallopian tubal ligation requiring anastomosis. Surgical methods: in patients with malignant tumors, cervical cancer, hysterectomy plus salpingectomy or salpingo-oophorectomy for stage Ⅰa1, and radical hysterectomy plus pelvic lymphatic dissection plus salpingectomy or salpingo-oophorectomy for stage Ⅰa2-Ⅱb. Endometrial carcinoma, performed by staging surgery. Staging surgery for EOC with early stage and cytoreductive surgery with advanced EOC. Vulvar cancer, extensive vulvar resection plus inguinal lymphadenectomy. In patients with benign diseases, uterine prolapse, hysterectomy plus salpingectomy or salpingo-oophorectomy plus sacrocolpopexy. Uterine leiomyoma or adenomyosis with uterus ≥ 12 weeks, hysterectomy plus salpingectomy or salpingo-oophorectomy. Myomectomy for patients requiring uterine preservation with uterine leiomyoma. Tubal anastomosis for patients with fallopian tubal ligation. (2) Surgical complications: intraoperative complications occurred in 25 patients (2.5%, 25/1 000), including 11 patients with vascular laceration, 11 patients with ureteral injury, 2 patients with bladder injury, and 1 patient with intestinal injury. Postoperative complications occurred in 130 patients (13.0%, 130/1 000), including 66 cases of lower limb venous thrombosis, 20 cases of lymphatic cyst, 8 cases of hydronephrosis, 9 cases of ileus, 16 cases with infection, 6 cases with genital fistula, 4 cases with trocar site herniation and 1 case with subcutaneous emphysema. The incidence of intraoperative complications was 3.1% (25/811) in malignant tumors and no case in benign diseases, the incidence rate in malignant tumors was significantly higher than that in benign diseases ( χ2=4.778, P=0.029). The incidence rate in cervical cancer (4.2%, 17/405) and EOC (3.6%, 4/112) were significantly higher than those in endometrial carcinoma (1.4%, 4/279) and vulvar cancer (0/15; P<0.05). The incidence of postoperative complications was 15.2% (123/811) in malignant tumors and 3.7% (7/189) in benign diseases. The incidence rate in malignant tumors was significantly higher than that in benign diseases ( χ2=17.807, P<0.01), but there were no significant difference among different malignant tumors ( χ2=4.318, P=0.229). (3) The correlative factors affecting the occurrence of surgical complications: patient′s age, BMI, previous pelvic or abdominal surgery history, the nature of disease (malignant or benign), operation time, and comorbidities had a significant impact on the incidence of postoperative complications ( P<0.05). Multivariate logistic regression analysis showed that the patient′s age ≥40 years old, BMI ≥25 kg/m 2, previous pelvic or abdominal surgery history, malignant tumors and comorbidities were independent influential factors of the postoperative complications ( P<0.05). Conclusions:Perioperative complications vary according to the type of the surgery. The age, BMI, previous pelvic or abdominal surgery history, malignant tumors, and comorbidities are influential factors of postoperative complications.

Objective:To investigate the feasibility and efficacy of Da Vinci robotic-assisted surgery in the early stage of ovarian cancer without inverted position.Method:s A retrospective chart review of the patients with early stage ovarian cancer was performed in the First Affiliated Hospital of Zhengzhou University from October 2014 to October 2018. Patients with early stage ovarian cancer underwent robotic-assisted surgical staging: 26 patients underwent the inverted position approach (inverted group) and 32 received the non-inverted position approach (no-inverted group). The operation time, intraoperative bleeding volume, the number of lymph nodes resection, post-operative anal exhaust time, the average hospitalization days and complications between two groups were compared.Result:s Surgeries were successfully performed between both groups. (1) The perioperative related indicators: the operation time and the postoperative anal exhaust time in the inverted group were significantly longer than those in the no-inverted group [(208±33) minutes vs (158±32) minutes, P<0.01; (2.6±0.5) days vs (2.1±0.8) days, P<0.01, respectively]. There were no significant differences (all P>0.05) in the intraoperative bleeding volume, the average hospitalization days and the number of lymph nodes resection. (2) The comparison of the incidence of surgical complications: there were no significant difference (χ 2=0.000, P>0.05) in the rate of lymphatic retention cyst [4% (1/26), 6% (2/32)]. Conclusions:Da Vinci robot system without inverted position in omentectomy is safe and feasible. Compared to the inverted position approach, it also provides remarkable advantages, including reduced operative time and faster return of bowel movement, but its long-term effects remain to be followed-up.