Objective To discuss the 3D printing modeling used to assist minimally invasive fixation with hollow screws for unstable pelvic fractures.Methods From January 2014 to January 2016,137 patients with unstable pelvic fracture received minimally invasive fixation with hollow screws and obtained complete follow-up at our department.In 65 of them,the fixation was assisted by 3D printing modeling;they were 37 men and 28 women,with an average age of 33.1 ± 4.9 years.In the other 72 cases,conventional fixation was performed without assistance of 3D printing modeling;they were 45 men and 27 women,with an average age of 32.6 ±4.7 years.The 2 groups were compared in terms of operation time,frequency of intraoperative fluoroscopy,reduction quality and curative effect.Results This cohort were followed up for 6 to 15 months (average,9 months).The 3D printing modeling group needed significantly less operation time (58.6 ± 13.4 min) and intraoperative fluoroscopy (29.3 ± 3.6 frequencies) than the conventional group (72.4 ± 12.4 min and 36.6 ± 2.8 frequencies) (P ＜ 0.05).According to the Matta scoring criteria,the quality of pelvic reduction was evaluated as excellent in 21 cases,as good in 30 cases,as fair in 13 cases and as poor in one in the 3D printing group,yielding an excellent and good rate of 78.5％ while as excellent in 22 cases,as good in 36 cases,as fair in 12 cases and as poor in 2 cases in the conventional group,yielding an excellent and good rate of 80.6％.According to the Majeed scoring criteria,the curative effect was evaluated at the last follow-up as excellent in 27 cases,as good in 26 cases,as fair in 11 cases and poor in one in the 3D printing group,giving an excellent and good rate of 81.5％ while as excellent in 30 cases,as good in 28 cases,as fair in 13 cases and as poor in one in the conventional group,giving an excellent and good rate of 80.6％.There were no statistically significant differences between the 2 groups in reduction quality or curative effect (P ＞ 0.05).No nonunion or iatrogenic neurovascular lesions happened during the follow-up period.Conclusion 3D-printing modeling is helpful for a good reduction and minimally invasive fixation with hollow screws for unstable pelvic fractures by reducing operation time and intraoperative fluoroscopy.

Objective: To investigate the effects and related mechanism of bivalirudin on the survival of random skin flap on the back of rat. Methods: Thirty SD rats were divided into bivalirudin group and normal saline group according to the random number table, with 15 rats in each group. The random flap model with size of 9 cm×3 cm was reproduced on the back of rats in two groups. Immediately post injury, rats in bivalirudin group were intraperitoneally injected with 5 mg/mL bivalirudin (0.8 mL/kg), while rats in normal saline group were intraperitoneally injected with normal saline (0.8 mL/kg) once a day. The continuous injection lasted for 7 days. The flap was divided into distal area, middle area and proximal area averagely based on the flap blood supply. On post injury day (PID) 1, 3, and 7, the overall survival of each area of flap was observed with naked eyes. On PID 7, the survival rate of flap was calculated, and then the morphology of skin tissue at the center of the three areas of flap was observed by HE staining, the microvessel density (MVD) of the middle area of flap was calculated, and the expression of vascular endothelial growth factor (VEGF) of the middle area of flap was detected with immunohistochemical staining. Data were processed with t test. Results: (1) On PID 1, flaps of rats in two groups had different degrees of swelling, mainly concentrated in distal area, but there was no obvious necrosis. The middle area and proximal area of flaps in two groups were survived. On PID 3, the necrosis of flaps of rats in two groups was concentrated in the middle area, while the proximal area of flap was still in survival state, and most distal area of flap was necrosis with a little scab. On PID 7, the necrosis of middle area of flaps of rats in two groups was gradually fused, and the survival area of flap of rats in bivalirudin group was larger than that in normal saline group. The distal area of flap was almost necrotic, and the proximal area of flap was almost survived. (2) On PID 7, the survival rate of flap of rats in bivalirudin group was (64±4)%, significantly higher than that in normal saline group [(45±3)%, t=13.49, P<0.01]. (3) On PID 7, the histological morphology of distal area of flap of rats in two groups was similar, the inflammatory cells were infiltrated abundantly, and tissue edema was obvious. A large number of new blood vessels appeared in the middle area of flap of rats in bivalirudin group, with the formation of collateral vessels, and basic dilation of new blood vessels was seen. There were fewer new blood vessels appeared in the middle area of flap of rats in normal saline group, and dilation of new blood vessels was not obvious. There was little inflammatory cells infiltration in the proximal area of flap of rats in two groups. Compared with that in normal saline group, tissue edema extent of proximal area of flap of rats in bivalirudin group was less, and expansion was observed in more blood vessels. (4) The MVD of middle area of flap of rats in bivalirudin group was (26±5)/mm^2, significantly higher than that in normal saline group [(18±3)/mm^2, t=5.43, P<0.05]. (5) The expression of VEGF of middle area of flap of rats in bivalirudin group was 6 534±384, significantly higher than that in normal saline group (4 659±448, t=12.31, P<0.05). Conclusions Bivalirudin can promote the survival of random skin flap in rats, and the mechanisms may include reducing the formation of thrombosis, improving the blood supply of flap, and increasing the expression of VEGF, promoting the formation of new blood vessels.

Objective To validate the effect of Renji acute kidney injury score (RAKIS) on predicting patients with acute kidney injury (AKI) after cardiac surgeries,and make comparison with Cleveland score,simplified renal index (SRI) and acute kidney injury following cardiac surgery (AKICS).Methods Patients undergoing open heart surgery from 2008/01/01 to 2010/10/31 in Renji hospital were enrolled,and their scores of those four scoring models were calculated.AKI patients were diagnosed by KDIGO,and those scores of AKI patients and non-AKI patients were compared.Receiver operating characteristic (ROC) curve and area under curve (AUC) were used to decide the predictive values of those models.Results A total of 1126 patients were chosen in this cohort,with the average age of (58.43±14.88) years (rang from 18 to 88).The male to female ratio was 1.47:1.And 355(31.5％) patients were developed AKI.AKI stage Ⅰ,Ⅱ and Ⅲ were 65.4％,23.7％ and 11.0％ respectively.RAKIS was significantly higher in AKI patients than in non-AKI patients (17.5 vs 9.0,P ＜ 0.001).The AUCs of RAKIS to predict AKI,AKI Ⅱ-Ⅲ stages,renal replacement therapy (RRT)and in-hospital death were 0.818,0.819,0.800 and 0.784 respectively.The AUCs of Cleveland score and SRI were 0.659 to 0.710,lower than those of RAKIS and AKICS.AKICS had lower value for predicting AKI and AKI Ⅱ-Ⅲ stages (AUC 0.766 and 0.793),but good value in predicting RRT and inhospital death after surgery (AUC 0.804 and 0.835) as compared with RAKIS.Conclusions RAKIS is valid and accurate in the discrimination of KDIGO defined AKI patients,while for predicting the composite end point,AKICS may be more useful.

Objective:To investigate whether the Garden indexes can serve as a criterion for rotational displacement of femoral neck fracture.Methods:Ten cadaveric specimens of healthy human proximal femur were used for this study. They came from 3 males and 2 females who had died at the age from 45 to 70 years old. A Kirschner wire of 2.0 mm in diameter was implanted into the center of the femoral head. Osteotomy was conducted perpendicular to the middle line of the femoral neck. The rotational angles were marked on the distal osteotomy surface. Each cadaveric specimen was rotated sequentially at pronation and supination angles of 0°, 10°, 20°, 30°, 40°, 50°, 70° and 90°, respectively. X-ray images of anterior-posterior and lateral views were taken to record all the rotations of the specimens. Picture Archiving and Communication Systems (PACS) were used to measure the Garden indexes and compare them among anterior-posterior and lateral X-ray films of different pronation and supination angles. Changes in the area of the femoral head fovea at different rotation angles were observed as well.Results:There were no significant differences in the auterior-posterior or latera Garden indexes from 0° to pronation or supination 30°, with all the Garden values >155° ( P>0.05); from pronation of 40° to pronation of 90°, the Garden indexes were 152.36°±1.41°, 146.04°±1.64°, 143.95°±0.60° and 141.73°±0.60° for anterior-posterior views and 172.54°±0.86°, 168.57°±0.98°, 157.18°±1.17° and 156.47°±1.63° for lateral views, showing a significant difference between rotational angles ( P<0.05); from supination of 40° to supination of 90°, the Garden indexes were 151.67°±1.06°, 147.32°±1.82°, 142.77°±0.75° and 139.88°±1.48° for anterior-posterior views and 172.28°±0.79°, 166.76°±1.02°, 155.67°±1.74° and 154.16°±1.27° for lateral views, showing a significant difference between rotational angles ( P<0.05). The area of the femoral head fovea decreased gradually with the increase in pronation angle, and increased gradually with the increase in supination angle. Conclusions:The Garden indexes cannot serve as an accurate indication of rotational displacement in reduction of femoral neck fracture when the pronation or supination angles ranges from 0° to 30°. Changes in the area of the femoral head fovea can help determine the rotational displacement of the femoral neck fracture.

Objective:To introduce a surgical method and clinical effect of using Masquelet technique combined with skin graft to cover chronic refractory wounds in elderly patients.Methods:From September 2020 to September 2022, 20 elderly patients with wounds of bone or tendon exposure in lower limbs were treated in the Department of Wound Repair, the Second Affiliated Hospital of Wenzhou Medical University. Due to the age and poor general condition of the patients, flap transfer for wound coverage were not allowed. Masquelet technique was therefore applied in the treatment of chronic wounds of such patients. Sizes of wounds were found at 4.5 cm×3.0 cm to 15.0 cm×6.0 cm and all accompanied with tendon and bone exposure, after thorough debridement. Wounds were then sealed with antibiotic bone cement several times. After having induced formation of membrane in wounds, free mesh skin graft was used to cover the refractory wounds. The patients were entered in follow up regularly after surgery at outpatient service, and telephone or video reviews. The wound healing of patients and whether there were related complications in the skin donor area were observed. The number of operation times in the first stage was 1-4 with an average of 1.3 times ± 0.7 times. Lower Extremity Function Scale (LEFS) was used to evaluate the recovery of lower limb function.Results:All 20 wounds healed well. The follow-up time was 3-12 months, with an average of 7.6 months. The appearance and texture of the skin in the wounds area were satisfactory. The mean LEFS was 69.83 point ± 10.82 point.Conclusion:Using Masquelet technique combined with free skin grafting to treat refractory wounds in the elderly patients can achieve satisfactory clinical outcomes. It is a simple and reliable supplement to the wound repair, and can reduce the surgical risk.