Objective To simulate the microflow field environment between the anastomotic nail surface and intestinal wall tissue after implantation and to study the effect of hydrophobic surfaces on the flow rate of extracellular fluid and the fluid shear force on the wall to regulate bacterial adhesion through changes in the flow field.Methods The microstructure of shark skin was observed,and a simplified two-dimensional(2D)movement model of bacteria in a microflow field was established.Using computational fluid dynamics(CFD)numerical simulation,the movement of bacteria on a smooth surface and micro-textured surface in a static and dynamic flow field were simulated.The flow field characteristics around bacteria and the magnitude of fluid shear force under the two surface environments were compared,and the internal mechanism of the fluid shear force affecting bacterial adhesion was analyzed.Results The addition of the biomimetic microtexture enhanced the flow rate of the extracellular fluid in the microflow field,and the fluid had little viscous effect on the bacteria in the static flow field.The fluid in the dynamic flow field had a stronger pushing effect on the bacteria.The fluid shear force on the microtextured wall increased when the pit width was within a specific range.Conclusions The bionic micro-textured surface of the anastomotic nail can accelerate the flow rate of extracellular fluid,increase the fluid shear force of micro-textured walls and bacteria,and influence bacterial adhesion.These result provide a theoretical basis for studying bacteriostatic surfaces of anastomotic nails.

Objective To investigate the effect of radiation on cardiomyocyte apoptosis and its related mechanism.Methods Rat H9C2 cardiomyocytes were divided into blank control group,X-ray irradiation group(X-ray group),X-ray irradiation+microRNA(miRNA)-134-5p inhibitor group(X-inhibitor group)and X-ray irradiation+miRNA-134-5p inhibitor negative control group(X-NC group).H9C2 cardiomyocytes were irradiated with 6 Gy X-ray,and the changes of various indexes were detected 48 h after irradiation.Cell viability was detected by cell counting kit 8 assay.The apoptosis rate was detected by flow cytometry and Hoechst 33342 staining.The level of reactive oxygen species(ROS)in cells was detected by DCFH-DA fluorescence probe.The mitochondrial membrane potential was detected by JC-1 method.The activity of superoxide dismutase(SOD)and the level of malondialdehyde(MDA)in cells were measured by kits.The expression of miRNA-134-5p was detected by quantitative polymerase chain reaction.The protein expression of brain-derived neurotrophic factor(BDNF),protein kinase B(Akt),phosphorylated Akt(p-Akt),Bcl2 and Bax was detected by Western blotting.Results Compared with the blank control group,in the X-ray group the levels of ROS and MDA were significantly increased,the activity of SOD was significantly decreased,the decreased percentage in mitochondrial membrane potential was significantly increased,the number of micronuclei of DNA damage was significantly increased,and the apoptosis rate was significantly increased(all P＜0.01).Compared with the X-ray group,all the indexes of the X-inhibitor group were reversed(P＜0.05 or P＜0.01),while there was no significant difference in the above parameters in the X-NC group(all P＞0.05).Compared with the blank control group,the X-ray group had a significant increase in the miRNA-134-5p level and significant reductions in the protein level of BDNF,Bcl2/Bax ratio,and p-Akt/Akt ratio(all P＜0.01).Compared with the X-ray group,the X-inhibitor group had a significant reduction in the level of miRNA-134-5p and significant increases in the protein level of BDNF,Bcl2/Bax ratio,and p-Akt/Akt ratio(all P＜0.01),and there was no significant difference in all parameters in the X-NC group(all P＞0.05).Conclusion X-ray irradiation can induce oxidative stress,mitochondrial damage,and DNA damage,eventually leading to apoptosis in rat cardiomyocytes,and the mechanism may involve miRNA-134-5p/BDNF/Akt signaling pathway.

OBJECTIVE To investigate the effect of gene polymorphism on opioid-induced constipation. METHODS The target genes related to opioid-induced constipation were screened out through searching guidelines， databases and evidence-based medical data， and then 100 cancer pain patients who received opioid drugs for analgesia were included as the study subjects. According to whether there were adverse effects of constipation after medication or not， they were divided into test group and control group， with 50 cases in each group. The target gene was detected by PCR or fluorescence in situ hybridization. The SNPStats program was used to carry out Hardy-Weinberg balance test and correlation analysis between gene polymorphism and opioid-induced constipation. The multivariate Logistic regression analysis was used to explore the relevant predictive factors of opioid-induced constipation， and receiver operating characteristic （ROC） curve of subjects was drawn to analyze the effectiveness of each predictive factor in predicting opioid-induced constipation. RESULTS CYP2D6， CYP3A5*3， ABCB1 and OPRM1 were selected as target genes for detection. The results of genotype detection showed that the frequency distribution of CYP2D6 （rs1065852， rs1135822， rs16947， rs28371725， rs28371735）， CYP3A5*3 （058rs776746）， ABCB1 （062rs1045642）， OPRM1 （047rs1799971） alleles were consistent with Hardy-Weinbergbalance test. The correlation analysis results showed that the proportion of genotype GG and AG in CYP3A5*3 （058rs776746， 163.com A＞G） and genotype AA and AG in OPRM1 （047rs1799971， A＞G） of patients was significantly higher in test group than that in the control group （P＜0.05）. Multivariate Logistic regression analysis showed that medication duration， CYP3A5*3 and OPRM1 gene polymorphism could be used as predictors of opioid- induced constipation in patients （P＜0.05）. The ROC curve analysis results showed that the areas under the ROC curves for medication duration and CYP3A5*3， OPRM1 gene polymorphism were 0.648， 0.640 and 0.670， respectively， with the optimal cutoff values of 124.0， 0.5 and 0.5， respectively. CONCLUSIONS Genotype GG and AG in CYP3A5*3 （058rs776746，A＞G） and genotype AA and AG in OPRM1 （047rs1799971，A＞G） are associated with opioid-induced constipation， which are expected to become clinical predictors of opioid-induced constipation， and more attention should be paid to the occurrence of constipation in patients who have been taking opioids for a long time.

Objective:To investigate the clinical significance of excessive inlet view in fluoroscopy-assisted placement of sacroiliac screws.Methods:Included for this prospective study were 47 patients with unstable pelvic fracture who had been admitted to Department of Orthopaedic Trauma, Xi'an Honghui Hospital between January 2020 and January 2021. There were 30 males and 17 females, with a mean age of 39.4 years (from 25 to 66 years). By the Tile classification, 21 fractures were type B and 26 ones type C. The inlet view and the angle of excessive inlet view were measured before operation. The intraoperative placement of sacroiliac screws was assisted by C-arm fluoroscopy navigation in the excessive inlet view. The positions of sacroiliac screws were verified by CT or O-arm fluoroscopy after operation. The screw placement time, fracture reduction quality, fracture healing time, and pelvic function at the last follow-up were recorded.Results:A total of 67 screws were implanted in the 47 patients, including 56 sacroiliac screws. The insertion time for each screw averaged 19.9 min (from 9 to 31 min); the angle of excessive inlet view averaged 17.38° (from 12.1° to 24.8°). Verification by O-arm fluoroscopy or CT revealed that all sacroiliac screws were located in the sacral canal without dislocation or breaking through the cortical bone. By the postoperative Matta scoring, the reduction was excellent in 22 cases, good in 17, acceptable in 6, and poor in 2, giving an excellent to good rate of 83.0%(39/47). The average follow-up time for the 47 patients was 9.5 months (from 5 to 15 months); fracture healing time averaged 10.5 weeks (from 7 to 16 weeks). By the Mejeed scoring at the last follow-up, the pelvic function was excellent in 26 cases, good in 15 and acceptable in 6, giving an excellent to good rate of 87.2% (41/47).Conclusions:Fluoroscopy in the excessive inlet view is a simple and easy intraoperative technique. It can improve accuracy and safety of sacroiliac screw placement because it allows clear identification of the posterior border of the sacrum and effectively avoids iatrogenic injury to the sacral nerve caused by screws breaking through the bone cortex.

Objective:To explore the value of Hong′s single-stitch duct to mucosa pancreaticoenterostomy(HSDMP) in laparoscopic pancreaticoduodenectomy(LPD).Methods:The perioperative clinical data of 300 patients undergoing LPD admitted to the Second Department of Hepatobiliary Surgery in the First Hospital of Jilin University from April 2015 to March 2019 were retrospectively analyzed. The patients were categorized into pancreatic fistula group( n=43) and non pancreatic fistula group( n=257). according to the presence or absence of postoperative pancreatic fistula. Among them, pancreaticojejunostomy was performed with HSDMP in 210 patients, and 90 patients underwent traditional pancreaticoenterostomy. Univariate and multivariate logistic regression were used to analyze the risk factors for the development of pancreatic fistula after LPD, and the difference on the time of pancreaticojejunostomy and the incidence of postoperative pancreatic fistula were compared between HSDMP and traditional pancreaticojejunostomy. Results:Univariate analysis showed that the differences on BMI, abdominal operation history, pancreatic texture, and pancreatic duct diameter were statistically significant compared with non-pancreatic fistula group (all P value <0.05). Multivariate logistic regression showed that BMI ( OR1.180, 95% CI1.047-1.338, P=0.008) and pancreatic texture( OR=0.375, 95% CI 0.135-0.861, P=0.036) were independent risk factors for pancreatic fistula after LPD. Compared with traditional pancreaticojejunostomy, HSDMP was associated with shorter anastomosis time and low incidence of postoperative pancreatic fistula, but there was no statistical significance between the two groups. Conclusions:The independent risk factors for pancreatic fistula are high BMI and soft pancreatic texture. Compared with traditional pancreaticojejunostomy, HSDMP does not prolong LPD time and increase the incidence of postoperative pancreatic fistula.

Objective:To evaluate the effects of weight-bearing area compression injury of the femoral head on the prognosis of elderly acetabular fractures after open reduction and internal fixation.Methods:A retrospective analysis of 36 elderly patients with acetabular fractures treated with open reduction and internal fixation during January 2014 to January 2018 were conducted. All patients with compression injury of the weight-bearing area of the femoral head, including 22 males and 14 females with 73.2±6.5 years old (range 60-87 years old), were included. The compression injury of weight-bearing area of the femoral head was not treated. According to the Letournel-Judet classification of acetabular fractures, there were 14 cases with both-column, 12 cases with anterior column and posterior hemitransverse, 4 cases with T type, 4 cases with transverse, and 2 cases with posterior column+ posterior wall. A total of 14 cases were accompanied by acetabular joint surface compression, while 29 cases were accompanied by joint dislocation. The Merle d'Aubigné score was used to evaluate the hip function during follow-up. The Matta classification method was used to evaluate the results of acetabular fracture reduction. The Kellgren-Lawrence classification standard and Ficat-Alert staging method were used to evaluate the traumatic arthritis of the hip and femoral head necrosis, respectively. During the follow-up, the femoral head necrosis with stage III, IV, or traumatic arthritis III, IV, or with indications for joint replacement was defined as surgery failure. CT scans of the pelvis were performed before and at 2-5 days after operation. The compression size of the femoral head on the coronal and axial planes of the CT scan was calculated for the compression volume. The compression severity was divided into small (<1 cm 3), medium (1-2 cm 3) and large (>2 cm 3) according to the volume. Binary Logistic regression analysis was used to analyze whether the postoperative measurement of the femoral head compression volume was associated with the risk of surgical failure. Results:All patients were followed up for 34.7±8.9 months (range 25-54 months). There were 7 cases with large compression of femoral head, 14 cases with medium, and 15 cases with small pre-operatively. However, there were 12 cases, 10 cases and 14 cases with large, medium and small at 2-5 days after operation, respectively. Six cases were excellent reduction, 22 cases were good, and 8 cases were poor. Thus, the excellent and good rate was 78% (28/36). At the last follow-up, Merle d'Aubigné score was excellent in 2 cases, good in 8 cases, fair in 5 cases, and poor in 21 cases. The excellent and good rate was 28% (10/36). There were 20 cases with surgery failure with 56% (20/36) failure rate. There were no statistically significant differences in the patient's age, body mass index, operation duration, blood volume, fracture type, fracture reduction, combined acetabular joint surface compression, and combined joint dislocation between the two groups. However, there was a statistically significant difference in the frequency distribution of compression volume in the weight-bearing area of the femoral head after surgery (χ 2=22.047, P<0.001). In patients with large, medium, and small-volume compression of the femoral head weight-bearing area, the surgery failure rates were 92%, 80%, and 7%, respectively. The large and medium-volume compression of the femoral head weight-bearing area were independent risk factors for surgical failure. Conclusion:Open reduction and internal fixation can be used to treat elderly patients with acetabular fractures combined with femoral head compression injury. Despite satisfactory reduction for acetabular fractures, the larger volume of femoral head compression affects the clinical outcomes with extremely high rate of surgical failure within 2 years.

Objective:To compare the predictive values between 4 risk assessment scales for deep venous thrombosis (DVT) in patients with pelvic or acetabular fracture.Methods:The clinical data of 235 patients with pelvic or acetabular fracture were retrospectively analyzed who had been admitted to Xi'an Honghui Hospital from July 2014 to July 2018. They were 168 males and 67 females, aged from 18 to 90 years (average, 43.5 years). They were divided into a DVT group and a DVT-free group according to the results of vein ultrasongraphy. The RAPT, Caprini, Wells, and Autar scales were used respectively to assess the risk of DVT in the patients. The 2 groups were compared in terms of the scores of the 4 scales. After the receiver operating characteristic curve (ROC) was drawn and the area under the ROC curve (AUC) was calculated, the predictive values of the 4 scales were evaluated for lower limb DVT in the patients with pelvic or acetabular fracture.Results:Of the 235 patients, 104 (44.3%) had DVT. There was no statistically significant difference in the preoperative general data between the 2 groups, showing comparability ( P>0.05). The DVT group scored significantly higher in RAPT, Wells and Autar scales than the DVT-free group( P<0.05). The AUCs for the RAPT, Caprini, Wells, and Autar scales were respectively 0.84±0.02, 0.65±0.05, 0.81±0.02 and 0.72±0.03, showing significant differences ( F=1.254, P=0.031). The AUCs for RAPT and Wells scales were significantly higher than those for Caprini and Autar scales, and the AUS for Autar scale was significant higher than that for Caprini ( P<0.05). The sensibilities for RAPT, Caprini, Wells and Autar scales were respectively 94.0%, 65.0%, 90.6% and 84.0% while the specificities for them 62.1%, 51.8%, 67.2% and 32.5%. Conclusion:Although all the 4 scales have a certain predictive value for the DVT risk in patients with pelvic or acetabular fracture, RAPT and Wells scales are more valuable.

Objective To evaluate the clinical treatment of unstable pelvic fractures by posterior ring fixation using percutaneous minimally invasive pedicle screws following anterior ring fixation.Methods From January 2010 to January 2016,31 patients with unstable pelvic fracture were treated at our department.They were 20 males and 11 females,with an average age of 44.4 years (range,from 18 to 65 years).According to the Tile classification,6 cases were type B2,8 cases type B3,12 cases type C1,and 5 cases type C2.The anterior pelvic ring was fixated in supine position first,and the posterior pelvic ring was fixated next using percutaneous minimally invasive pedicle screws.The operation time,intraoperative bleeding,and frequency of fluoroscopy needed for the posterior ring fixation were recorded.Reduction quality,complications like loss of reduction and pelvic function at the final follow-up were also assessed.Results For the posterior ring fixation in the 31 patients,the operation time ranged from 40 to 60 minutes (average,50.7 minutes),blood loss from 30 to 80 mL (average,42.9 mL),and fluoroscopic frequency from 7 to 12 times (average,9.7 times).By the Tornetta evaluation,the reduction was rated postoperatively as excellent in 15 cases and as good in 16 ones,yielding an excellent and good rate of 100％.Twenty-nine patients obtained complete follow-up for 12 to 83 months (average,34.7 months),and they achieved bone union after an average of 14.5 weeks (range,from 12 to 16 weeks).According to the Majeed criteria for pelvic function at the final follow-up,10 cases were rated as excellent,16 cases as good,and 3 cases as fair,giving an excellent and good rate of 89.7％.No reduction loss,incision infection,vascular or nerve injury,screw loosening or breakage,or fracture displacement was observed during follow-up.Conclusion In the treatment of unstable pelvic fractures,posterior ring fixation using percutaneous minimally invasive pedicle screws following anterior ring fixation can lead to less operation time,intraoperative bleeding and fluoroscopic radiation,and satisfactory fracture reduction and functional recovery of the pelvis as well.

Objective To investigate the therapeutic efficacy of contralateral less invasive stabilization system (LISS) through a medial-posterior approach for fractures of femoral medial condyle.Methods From December 2010 to December 2014,14 patients with fracture of femoral medial condyle were treated surgically at our department.They were 10 males and 4 females,aged from 33 to 64 years (average,44.6 years).By AO classification,10 cases were type 33-B2 and 4 cases type 33-B3.Causes of injury included traffic accident in 7 cases,falling in 6 and heavy object crush in one.Internals from injury to operation ranged from 3 to 10 days (average,5.4 days).All the patients were treated by open reduction and internal fixation with contralateral LISS plate or T plate through a knee medial posterior approach.Results The 14 patients were followed up for 12 to 24 months (average,18 months).All fractures got bony healing after 3 to 5 months (average,3.5 months).No collapse of joint surface,joint stiffness,joint infection,malunion or nonunion occurred.According to the Schatzker-Lambert criteria for functional recovery of the distal femoral fractures,the function of the affected knee was assessed at the last follow-up as excellent in 9 cases,good in 3,fair in one and poor in one.Conclusion Open reduction and internal fixation with contralateral LISS plate through a medial-posterior approach is effective for fractures of femoral medial condyle due to its strong buttress,rigid fixation,advantage for early functional exercise,and satisfactory therapeutic outcome.

Objective To compare the perioperative incidence of deep venous thrombosis (DVT) and level of plasma D-dimer between different ages in patients with lower limb fracture in Northwest China.Methods The data were retrospectively analyzed of the 1,185 patients with lower limb fracture in 5 provinces in Northwest China from July 2014 to March 2017.They were 583 males and 602 femals,with an average of 60.3 years(from 18 to 102 years).Of them,723 were from Shaanxi Province,148 from Gansu Province,137 from Qinghai Province,128 from Ningxia Hui Nationality Autonomous Regions and 49 from Xinjiang Uygur Autonomous Region.They were divided into a young group (≤44 years old) (n =288),a middle-aged group (from 45 to 59 years old) (n =256),a junior elderly group (from 60 to 74 years old) (n =263),and a senior elderly group (≥75 years old) (n =378).The incidences of perioperative deep venous thrombosis (DVT) and levels of plasma D-dimer were compared between the 4 age groups.Results The DVT incidences before and after operation in the young group were significantly lower than in the other 3 groups (P ＜ 0.05);the DVT incidence after operation in the middle-aged group was significantly lower than that in the junior elderly group (P ＜ 0.05).The pre-and post-operative levels of plasma D-dimer increased with the age of the patients;the pre-and post-operative levels of plasma D-dimer in the senior elderly group were significantly higher than in the other 3 groups (P ＜ 0.05).Conclusions The perioperative incidence of DVT was high in the elderly patients with lower limb fracture in Northwest China,peaking in the age range from 60 to 74 years old.The pre-and post-operative levels of plasma D-dimer increased with the age of the patients.