BACKGROUND: Individual three-dimensional (3D) scaffolds can be constructed by 3D printing via Computer Aided Design based on the given anatomical measurements of related tissues. A rapid and accurate reconstruction of bone, cartilage, muscle and vessel also can be achieved by 3D printing; however, many problems still remain unsolved.OBJECTIVE: To summarize the principle and classification of 3D printing, the classification, characteristics and histocompatibility of scaffolds through reviewing the articles addressing 3D printing applied in bone tissue engineering,thereby providing theoretical foundation for the study on the construction of tissue-engineered bone.METHODS: PubMed and CNKI databases were retrieved for the literatures regarding the application of 3D printing technology in bone tissue engineering published from January 2001 to January 2017 using the keywords of three-dimensional printing, rapid prototyping manufacturing, bone tissue engineering in English and Chinese,respectively. Finally, 30 articles were reviewed and discussed in accordance with the inclusion and exclusion criteria.RESULTS AND CONCLUSION: The microstructures of normal tissues can be reconstructed and seed cells are printed on the 3D scaffolds synchronously by 3D printing technology. Moreover, the scaffold degradation and cell differentiation are synchronous, which contributes to tissue repair. Biological ceramics have been widely used in bone tissue engineering because of its good biocompatibility and mechanical properties. However, the urgent problems such as angiogenesis and cellular signal transduction still need to be addressed.

Objective To evaluate the effect of domestic wire-reinforced epidural catheter on the occurrence of adverse events during epidural block.Methods Three hundred ASA Ⅰ or Ⅱ patients of both sexes,aged 18-64 yr,weighing 41-78 kg,scheduled for elective operations under combined spinal-epidural anesthesia,were randomly divided into 3 groups (n =100 each):polyvinyl chloride epidural catheter group (group A),imported wire-reinforced epidural catheter group (group B) and domestic wire-reinforced epidural catheter group (group C).Combined spinal-epidural anesthesia was performed routinely.The corresponding epidural catheter was inserted in each group.The catheterization without difficulty,paresthesia during catheterization,the number of patients in whom blood or cerebrospinal fluid was withdrawn from the epidural catheter,intravascular catheter insertion,injection obstruction,easiness during removal of the catheter,bleeding after removal,postoperative paresthesia and epidural hematoma within 1 week after operation were recorded.Results Compared with A group,the incidences of paresthesia during catheterization,the number of patients in whom blood or cerebrospinal fluid was withdrawn from the epidural catheter,injection obstruction and postoperative paresthesia were significantly decreased (P ＜ 0.05),and no significant change was found in the other parameters in B and C groups (P ＞ 0.05).There was no significant difference in all the parameters between B group and C group (P ＞ 0.05).Conclusion Domestic wire-reinforced epidural catheter can decrease the occurrence of catheterization-induced damage to the nerve and blood vessels and the efficacy is comparable with that of imported wire-reinforced epidural catheter.

Objective:To evaluate the gastric emptying in the patients with cholelithiasis and in the patients following cholecystectomy by ultrasonography.Methods:Thirty patients with cholelithiasis, 30 post-cholecystectomy patients and 30 healthy volunteers, of either sex, aged 18-64 yr, with body mass index of 18-30 kg/m 2, of American Society of Anesthesiologists Physical Status classification Ⅰor Ⅱ, were selected and divided into cholelithiasis group (group CH), post-cholecystectomy group (group PC) and healthy volunteer group (group HV). The indigestion scores of the enrolled subjects in the past 3 months were assessed; the subjects took a semi-solid test meal (300 kcal) in the fasting state, and the cross-sectional area (CSA) of the gastric sinus was measured using ultrasound at fasting (T 0) and 5, 15, 30, 45, 60, 90 and 120 min after the test meal was taken (T 1-7). The gastric emptying fraction at T 5, 6 was calculated. The gastric half-emptying time and remaining area of the gastric sinus at T 7 were also calculated. Results:Compared with group HV, dyspepsia scores were significantly increased within the past 3 months ( P<0.05), the CSA of the gastric sinus was increased at T 3-7, the gastric emptying fraction was decreased at T 5-6, the gastric half-emptying time was prolonged, and the remaining area of the gastric sinus was increased at T 7 in group CH and group PC ( P<0.05). Compared with group CH, the CSA of the gastric sinus was significantly increased at T 4-7, the gastric emptying fraction was decreased at T 5, 6, the gastric half-emptying time was prolonged, and the remaining area of the gastric sinus was increased at T 7 in group PC ( P<0.05). Conclusions:Gastric emptying time is longer in the patients with cholelithiasis and in the patients following cholecystectomy than in healthy subjects and is further prolonged after cholecystectomy in the patients.

Objective:To evaluate the effect of individualized positive end-expiratory pressure (PEEP) ventilation strategy guided by driving pressure on intraoperative intracranial pressure in patients with moderate traumatic brain injury (TBI).Methods:Total of 111 patients aged 18-65 years old, with BMI of 17-28 kg/m 2, ASA grade of Ⅲ-Ⅳ, and Glasgow coma score of 9-11 before operation were treated with evacuation of intracranial hematoma in emergency. The patients were randomly divided into 0 cmH 2O PEEP group (Group 0 PEEP), 5 cmH 2O PEEP group (Group 5 PEEP) and individualized PEEP ventilation group (Group P) guided by driving pressure. The volume control ventilation mode is adopted, VT is 6 mL/kg, FiO 2 is 60%, and the inspiratory expiratory ratio is 1:2. Patients in Group 0 PEEP and Group 5 PEEP were given PEEP 0 or 5 cmH 2O for ventilation after tracheal intubation until the end of the operation. Patients in Group P were given individualized PEEP titration ventilation strategy guided by driving pressure after intubation. Blood gas analysis was performed at 5 min (T1) after tracheal intubation, 60 min (T3) after operation, and 5 min (T4) after operation. PaO 2, PaCO 2, and dynamic compliance (Cdyn) were recorded. The optic nerve sheath diameter (ONSD) was measured before anesthesia induction (T0), after PEEP titration in group P (T2, 10 min after ventilation in group 0 PEEP and 5 PEEP) and at T4; Serum neuron specific enolase (NSE) concentration was measured by ELISA before and 1 day and 3 days after operation; The occurrence of nervous system complications (intracranial infection, intracranial hypertension, epilepsy, brain edema, etc.) within 30 days after operation was followed up. Results:Compared with group 0 PEEP and 5 PEEP, Cdyn and PaO 2 in group P increased at T3-4 ( P<0.05), ONSD was not significantly different among the three groups ( P>0.05), NSE in group P decreased significantly at 1 and 3 days after operation, and the incidence of neurological complications in the three groups was not significantly different at 30 days after operation ( P>0.05). Conclusions:Individualized PEEP ventilation strategy guided by driving pressure can help improve lung and brain function in TBI patients.

Objective:To evaluate the effect of preoperative oral carbohydrate on gastric emptying in the patients undergoing laparoscopic cholecystectomy.Methods:One hundred patients of both sexes, aged 18-64 yr, with body mass index of 18-30 kg/m 2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, were divided into 2 groups ( n=50 each) using the random number table method: control group (group C) and preoperative oral carbohydrate group (group P). Patients underwent solid food fasting after 20: 00 on the night before surgery in both groups and drinking fasting after 21: 30 on the night before surgery in group C. Group P received 800 ml of 12.5% oral carbohydrate at 21: 30 on the night before surgery and 400 ml of oral similar carbohydrate from 5: 00 to 5: 30 in the morning before surgery.All the patients underwent ultrasound examination of the gastric sinus at 7: 30 on the operation day (2 h after oral carbohydrate, T 1) to determine the nature of gastric contents according to the qualitative analysis of images, and Perlas grade was performed, and the cross-sectional area (CSA) of the gastric sinus in a semi-sitting position and right lateral decubitus position was calculated, and gastric volume (GV) and gastric volume to weight ratio (GV/W) were calculated.For solids in the stomach or GV > 1.5 ml/kg was defined as a full stomach.Patients assessed as a full stomach at T 1 underwent antrum ultrasonography again before induction of anesthesia (at 3 h after oral carbohydrate, T 2). The occurrence of satiety at T 1 and T 2 in each group was recorded.The patient′s hunger score, thirst score, and satisfaction score during fasting were recorded at T 2.The reflux aspiration, occurrence of nausea and vomiting at 24 h after operation, postoperative time to first flatus and postoperative total length of hospital stay were recorded. Results:Compared with group C, the CSA in a semi-sitting position, CSA, GV and GV/W ratio in a right lateral decubitus position, incidence of satiety, and Perlas grade were significantly increased at T 1 ( P<0.05), no significant change was found in the incidence of satiety at T 2 ( P>0.05), preoperative hunger and thirst scores were significantly decreased, satisfaction scores were increased, the incidence of nausea and vomiting was decreased at 24 h after surgery, and the postoperative time to first flatus was shortened ( P<0.05), and no significant change in the postoperative total length of hospital stay was found in group P ( P>0.05). Conclusions:Oral carbohydrates before laparoscopic cholecystectomy may result in delayed gastric emptying in the patients with cholelithiasis, and the time window for oral carbohydrates can be appropriately shifted forward (3 h before surgery).

Objective:To evaluate the effects of controlled low central venous pressure (CLCVP) on the cerebral blood flow in the patients undergoing open hepatectomy.Methods:Thirty American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ patients of either sex, aged 18-60 yr, with body mass index of 18-30 kg/m 2, with Child-Pugh classification A and expected operation time of 2-4 h, undergoing elective open hepatectomy, were enrolled.After anesthesia induction, patients were placed at head-up tilt position, nitroglycerin 0.5-1.5 μg·kg -1·min -1 was infused, and furosamide 5-10 mg was intravenously injected when necessary to maintain CVP less than 5 cmH 2O during hepatectomy.After the end of hepatectomy, CLCVP was stopped, the infusion rate was increased to 10 ml·kg -1·h -1 with a crystalline gel ratio of 1∶2 to restore CVP to more than 5 cmH 2O.At 5 min after anesthesia induction (T 0), 5 min after head-up tilt (T 1), 5 and 15 min after CVP reaching the target (T 2, 3) and 5 min after the end of CLCVP (T 4), the blood flow of internal carotid artery was detected by ultrasound, and peak systolic velocity(IBVs), end diastolic velocity (IBVd)and vessel diameter of the internal carotid artery (ID)were measured by doppler ultrasound.Mean velocity [IBVm=(IBVs+ IBVd×2)÷3] and internal carotid artery blood flow [IBF=IBVm×π×(ID/2) 2×HR] were calculated.Heart rate (HR), mean arterial blood pressure (MAP), cardiac output (CO), stroke volume (SV), end-tidal pressure of carbon dioxide (P ETCO 2) and maximum airway pressure (P max) were recorded at each time point. Results:Compared with the baseline at T 0, MAP, CO, SV, IBVm and IBF were significantly decreased at T 2, 3 ( P<0.001), and no significant change was found in HR, P ETCO 2 and P max at T 1-4 ( P>0.05). The results of linear mixed-effects model analysis showed that the regression coefficients for CO, MAP, HR, and SV were 0.600 3, 0.022 88, 0.363 7, and 0.614 8, respectively ( P<0.05 or 0.01). Conclusions:CLCVP can decrease the cerebral blood flow in the patients, which is closely associated with decreased CO, MAP, HR and SV when used for open hepatectomy.

Objective:To classify the ultrasound features of ovarian tumors by modified gynecology imaging reporting and data system(mGI-RADS), and explore the clinical value of mGI-RADS in differentiating of benign and malignant tumors.Methods:The 242 ultrasound images of the adnexal mass from 221 patients with ovarian tumor who underwent ultrasound scan and proceeded surgeries in the Second Affiliated Hospital of Harbin Medical University from September 2017 and December 2019 were involved in the retrospective analysis and compared with the pathological results. According to the latest ultrasound terminology for adnexal masses proposed by the International Ovarian Tumor Analysis (IOTA), the adnexal masses were classified. The suspeted malignant sings were screened for mGI-RADS. Using GI-RADS and mGI-RADS classification systems, all the adnexal masses were double-blindly classified by two senior doctors and their diagnostic efficiencies were evaluated.Results:Among the suspected malignant signs proposed by IOTA, resistance index (RI)<0.5, central blood flow signal, ascites, irregular cystic wall with uneven thickness separation, mass composition (solid component ≥30% and silent shadow attenuation), and papillary structure≥7 mm, showed retatively higher OR values(14.282, 10.372, 9.653, 8.832, 5.851, 4.506, respectively. Using GI-RADS and mGI-RADS classification systems, the diagnostic consistency by the two senior doctors in differentiating benign and malignant ovarian neoplasms was good(Kappa=0.767, P<0.05). Grade Ⅳ was divided into three subtypes (Ⅳa, Ⅳb, Ⅳc) by the mGI-RADS, and their positive predictive values for malignant ovarian masses were 69.0%, 90.4% and 92.9% respectively. When a cut-off value >mGRⅣ was used to distinguish the benign and malignant adnexal tumors, the AUC was the largest, and its sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 93.4%, 93.1%, 90.4%, 95.2% and 93.2%, respectively. Conclusions:The mGI-RADS has a high clinical value in the differential diagnosis of ovarian tumors.

Objective:To evaluate the myocardial reserve effect in rabbits′ model of myocardial inshemia-reperfusion by layer-specific strain of speckle tracking imaging and low dose dobutamine stress echocardiography(LDDSE).Methods:Forty rabbits were randomly divided into two groups: ischemia-reperfusion group (IR group) and pharmacological postconditioning group (ATP-PostC group). Echocardiography examinations were performed at baseline, 60 min after ligation (before and after dobutamine stress), and 120 min after reperfusion (before and after dobutamine stress). The size of each chamber was measured and the left ventricular ejection fraction(LVEF) was calculated and the heart rate was recorded. The longitudinal strain of endocardium(SLsys-endo), longitudinal strain of myocardium(SLsys-mid), longitudinal strain of epicardium(SLsys-epi) were acquired. Triphenyl tetrazolium chloride(TTC) and Evans blue staining were applied in two rabbits randomly selected from each group at 60 min after ligation, dobutamine stress and 120 min after reperfusion, respectively.Results:①After coronary artery ligation, LVEF decreased in both groups( P<0.05), SLsys-endo, SLsys-mid, and SLsys-epi decreased in two groups( P<0.01). After low dose dobutamine stress, the SLsys-endo, SLsys-mid and SLsys-epi in the two groups increased, which was different from that after lagation( P<0.05). ②After 120 min reperfusion, the longitudinal strain of the myocardium of both groups increased compared with that after lagation( P<0.01, P<0.05), and the increase in ATP-PostC group was significantly higher than that in IR group( P<0.01). There was no significant difference between the IR group and the first LDDSE( P<0.05). After LDDSE again, the SLsys-endo and SLsys-mid in the two groups further increased, which was different from that after reperfusion ( P<0.05). And the SLsys-endo and SLsys-mid were higher in ATP-PostC group than those in IR group ( P<0.05). ③Pathological results showed that there was no significant difference in myocardial infarct size between IR group and ATP-PostC group at 60 min after ligation ( P>0.05). After 120 min reperfusion, the percentage of myocardial infarct size in the IR group was significantly higher than that in the ATP-PostC group ( P<0.05). Conclusions:Layer-specific strain of STI combined with LDDSE can early detect regional myocardial dysfunction and accurately assess myocardial reserve function, and with endocardial longitudinal strain being more sensitive.

Objective To investigate the incidence of abnormalities and adverse reactions of intrauterine device ( IUD) by three‐dimensional transvaginal ultrasound ,and guide the correct selection of IUD . Methods Female volunteers who came to our hospital for health check‐up from July 2016 to February 2018 were selected as subjects to obtain information of the belt loop time and number of loops . T hree‐dimensional transvaginal ultrasound was used to observe and record the IUD types and positions . T he incidence of location abnormalities ,adverse reactions and cervical lesions of differnet types of IUD were retrospectively analyzed . Results T wo thousand one hundred and thirteen eligible subjects were included in the study ,including 423 cases of McuIUD ,506 cases of circular ring ,405 cases of uterine ring ,372 cases of T‐ring and 407 cases of γ ring . T he statistical analysis showed that the incidence of adverse reactions after wearing rings was as high as 34 .07% ,and the adverse reaction rate of different IUD was different . McuIUD had the highest incidence of adverse reactions ,compared with the circular ring ,the uterine ring ,the T‐ring , and the γ ring ( 47 .99% vs 25 .88% ,27 .41% ,37 .10% ,33 .66% ; all P ＜ 0 .05 ) . Different IUD had different incidence of adverse reactions . T he low back pain rate in McuIUD and γ ring were higher than the other 3 IUDs . T he low back pain rate of McuIUD was higher than the circular ring ,the uterine ring and the T‐ring ( 23 .4% vs 15 .71% ,14 .07% ,13 .7 1% ; all P ＜ 0 .01 ) . Different types of IUD had different incidence of location anomalies . T he descending rate of the circular ring was higher than that of the McuIUD and γ ring ( 6 .32% vs 3 .30% ,3 .19% ; all P＜ 0 .05 ) ,and no statistically significant difference compared with the uterine ring and T‐ring ( 6 .32% vs 3 .45% ,4 .30% ; all P ＞0 .05 ) . T he incarceration rate of the mother ring was higher than that of the circular ring ,uterine ring and T‐ring ( 3 .07% vs 0 ,0 .25% ,0 .54% ;all P ＜0 .01) . T he intrauterine rotation rate of uterine ring and γ ring were higher than that of McuIUD , circular ring and T‐ring ( all P ＜0 .01) . Pregnancy ＞1 and ring times ≥2 were related with the occurrence of adverse reactions of IUD ( P ＜ 0 .05 ) . T he incidence of cervical erosion in the T‐ring was the highest compared with the McuIUD ,circular ring ,uterine ring ,and γ ring ( 30 .65% vs 16 .78% ,16 .80% ,18 .02% , 17 .69% ; all P ＜0 .01) . Conclusions The incidence of adverse reactions is higher in women with different types of IUD . T he incidence of different types of abnormal IUD position is different . T he frequency of pregnancy and band ring are related to the occurence of adverse veactions to IUD .

To evaluate the changes of myocardial viability and systolic function in rabbits with different ischemic periods by layer‐specific strain of ultrasound speckled tracking imaging ( ST I) and low dose dobutamine stress echocardiography ( LDDSE ) . Methods T hirty‐six rabbits were randomly divided into 3 groups( n ＝12) : ①myocardial infarction group Ⅰ :coronary artery occlusion for 45 min ; ②myocardial infarction group Ⅱ :coronary artery occlusion for 60 min ; ③ myocardial infarction group Ⅲ :coronary artery occlusion for 90 min . Echocardiography examinations were performed at baseline ,after ligation and low dose dobutamine stress . After the experiment ,rabbits were killed and the hearts were taken to assess viable or nonviable mycardium , triphenyl tetrazolium chloride and Evans blue staining were applied . Results ①After coronary artery ligation ,left ventricular ejection fraction( LVEF) decreased in 3 groups ( all P ＜ 0 .05 ) , the ventricular global endocardial longitudinal strain ( GSLsys‐endo ) , global myocardial longitudinal strain( GSLsys‐mid) ,and global epicardial longitudinal strain( GSLsys‐epi) decreased in 3 groups ( all P ＜ 0 .05 ) ,the longitudinal strain of endocardium ( SLsys‐endo ) ,longitudinal strain of myocardium ( SLsys‐mid) ,longitudinal strain of epicardium ( SLsys‐epi) decreased in viable myocardial ( all P＜0 .05) ; ②While low dose dobutamine stressing ,the GSLsys and SLsys increased in each groups ,and the GSLsys‐endo ,GSLsys‐mid ,GSLsys‐epi and SLsys‐endo of viable segments in each group were increased ( P＜0 .05) ; ③After ligation and low dose dobutamine stress ,the GSLsys in endocardium in three groups were different( P ＜0 .05) ,and the SLsys in endocardium of viable segments in three groups were different ( P＜0 .05) . Conclusions Layer‐specific strain of STI combined with LDDSE can accurately evaluate the changes of myocardial viability and systolic function in different ischemic periods ,and the longitudinal strain of endocardium is more sensitive ;moreover ,with the increase of coronary artery occlusion time ,the infarcted myocardium increases ,myocardial viability and systolic function decrease .