Objective To investigate the effects of internal plating with high and low moduli of elasticity on the stress and its distribution on the femoral shaft fracture. Methods A femur from a normal Chinese adult male was scanned by 64-detector row helical CT at 0. 5 mm interval. The CT images were used to establish a finite element model of the femur by software. The mid-femoral fracture was simulated in the model and fixated by eight-hole plates of Ti-6Al-4V (high modulus group, E = 110 GPa) and of Ti2448 (low modulus group, E = 30 GPa). When the femur was in axial compression, flexion and torsion loads, the stress and its distribution on the bone fracture site were analyzed to compare the biomechanics of the plates with high and low moduli. Results Under axial compression load, the contact stress between fracture ends in the low modulus group was larger than that in the high modulus group, while the max stress at the hole (11.47MPa) was smaller than that in the high modulus group (13.89 MPa) . Under four-point bending load, the contact stress in the low modulus group was still larger, while the bending movement was smaller. Under the torsion load, stress on the femur was well-distributed in both groups, but the max stress at the hole in the low modulus group (11.47 MPa) was smaller than that in the high modulus group (31.24 MPa). Conclusions Under internal fixation by plates of low modulus, the stress stimulus at the fracture site may be increased,while the stress concentrated at the hole may be decreased. The stress shielding of the low modulus plate may also be modified.

Objective To investigate the operative techniques of microsurgery treatment of M1 segment of middle cerebral artery (MCA) aneurysms via pterional approach in 132 cases.Methods Retrospectively analyzed the clinical manifestation,angiograms,and surgical operation data of 132 patients with M1 segment of MCA aneurysms who underwent microsurgery through pterional approach.Results Preoperative digital subtraction angiography (DSA) was conducted in 121 cases to identify the size,shape,orientation and relationship with blood vessels around the MCA aneurysms.The other 11 cases underwent emergency operation.Among the 132 cases,72 patients were discharged in good condition according to Glasgow Outcome Scale; 41 patients were in poor condition; 19 cases were dead or in predying state.Postoperative CT showed that49 cases occurred new infarction and 7 cases developed hydrocephalus or enlargement of ventricles.Ventriculoperitoneal shunt was conducted in 2 cases.Intraoperation rupture and bleeding of aneurysms occurred in 17 cases.Conclusion The aneurysms in M1 segment of the middle cerebral artery are mostly located in the bifurcation of M1 segment.Most branches and perforating arteries stem from middle cerebral artery trunk.Patients with Hunt-hess grade Ⅰ-Ⅲ MCA aneurysms or with Hunt-hess grade Ⅳ,Ⅴ should be treated with microsurgery as soon as possible.Inside Sylvian fissure approach is the most frequently adopted in microsurgery via pterional approach.It is key for the success of the operation to preoperatively understand the anatomy surrounding the aneurysms,have good microsurgical skills and employ correct methods of preventing and managing of rupture of aneurysm.It can relieve the secondary cerebral vasospasm to clear up hematocele in the cisterns or to wash the cisterns or use adhesive wound dressing on blood vessels during operation using papaverine.

Objective:To investigate the stress distribution in peri-implant bone with All-on-4 implant with various parameters by three-dimensional finite element method.Methods:An edentulous mandibular specimen was scanned by CT Mimcs.Geomagic,Uni-graphics,HyperMesh modeling software were used to establish All-on-4 implant finite element models with different inclination angles and corresponding cantilever lengths.1 50 N vertical static load was applied at the right end of the cantilever,peri-implant bone stress was analysed using Abaqus software.Results:When the distal implant inclined 0°with cantilever length of 1 9.5 mm,the peak stress in peri-implant cortical bone at the mesial and distal side was 25.526 MPa and 83.026 MPa respectively.When the distal implant in-clined 1 5°,30°and 45°with the cantilever length of 1 7.2 mm,1 3.3 mm and 9.8 mm,the stress in perio-implant cortical bone at distal side of the implant reduced by 1 2.4%,35.6% and 53.1 %,that at mesial side of the implant reduced by 1 3.6%,36.3% and 40.2%,respectively.Conclusion:From the perspective of the stress analysis,the design of All-on-4 distal implant with large incli-nation angle and short cantilever is superior to that with small inclination angle and long cantilever.

Objective To explore the neuroprotective effects ofβ-aescinate on brain edema in rats of traumatic brain injury (TBI). Methods A total of 78 male SD (Sprague Dawley) rats were randomly divided into three groups: sham-operation group (Sham), traumatic brain injury group (TBI) andβ-aescinate group, with 26 rats in each group. Rats of Sham group were anesthetized and surgically prepared only, but were not induced by cortical contusion. Electronic brain cortical damage impactor (eCCI) was used for establishing TBI model in TBI group and β-aescinate group after opening the bone window. TBI group was only established TBI model, but no intervention. After establishment of TBI model in β-aescinate group, β-aescinate (5 mg/kg body weight) was intraperitoneally injected, once every 24 hours. The modified neurological severity scores (mNSS) was used for evaluating changes of neurological function. After 48 hours, SD rats were sacrificed for hematoxylin and eosin (H&E) staining (n=6). Additionally, water content of the brain tissue was evaluated using the wet-to-dry weight ratio (n=10). Evans blue assay was performed to investigate the blood-brain barrier (BBB) permeability (n=4). The expression of aquaporin 4 (AQP4) was measured by Western blot assay (n=6). Results Compared with the Sham group, neurologic deficit, increased brain water content and the expression of AQP4 were found in TBI group (all P<0.05). Moreover, BBB permeability was destroyed. However, β-aescinate can improve the neurological function, reduce the brain water content and significantly decrease the expression of AQP4 in TBI rats. The BBB permeability was significantly improved in treatment group (all P<0.05). Conclusion These findings suggest that β-aescinate can reduce cerebral edema and improve neurological outcome in SD rats after TBI. This neuroprotection may be related with the down-regulation of AQP4 protein.

OBJECTIVE: To investigate the surgical treatment of cholesterol granuloma in middle ear. METHOD: Nineteen patients of cholesterol granuloma in middle ear were retrospectively study. All the patients were treated with tympanic tube insertion, canal wall up mastoidectomy or intact-tympanic canal wall down mastoidectomy respectively. RESULT: All the cases were followed up from 6 months to 3.3 years. Two patients recurred among the 4 patients treated with tympanic tube insertion, 3 patients recurred among 8 patients treated with canal wall up mastoidectomy, and no recurrence was found among 7 patients treated with intact-tympanic canal wall down mastoidectomy. 12 patients had their hearing improved obviously among 14 patients without recurrence. CONCLUSION For the juvenile patients with a short medical history occurred for the first time, tympanic tube insertion merely is a rea sonable choice after the factor of obstruction of the pharyngotympanic tube was removed. For the patients with a long medical history and comprehensive lesions, or occurred repeatedly after being treated with tympanic tube in sertion or canal wall up mastoidectomy, the intact-tympanic canal wall down mastoidectomy should be a good choice.
Adolescent ; Adult ; Child ; Cholesteatoma, Middle Ear ; surgery ; Ear Diseases ; surgery ; Ear, Middle ; Female ; Granuloma ; surgery ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Young Adult

Objective To explore the risk factors for vascular invasion and its influence on prognosis of resectable gastric cancer patients by analyzing the clinicopathological features. Methods We retrospectively analyzed the data of 1077 patients with stage Ⅰ-Ⅲ gastric cancer who underwent surgical resection. According to whether vascular invasion occurred, they were divided into LVI positive group (n=672) and LVI negative group (n=405). Logistic univariate and multivariate analyses were used for the relation between clinical pathological features and LVI. Survival analysis was used to study the relation between vascular invasion and survival rate in patients with stage Ⅰ gastric cancer. Results Univariate analysis showed that tumor size, type of differentiation, depth of invasion, lymph node metastasis, TNM stage, Lauren classification, nerve invasion and the increase of CEA, CA125 and CA199 were risk factors for vascular invasion (P < 0.05). Multivariate analysis showed that poor differentiation, deep invasion, lymph node metastasis, nerve invasion and elevated CA724 were independent risk factors for vascular invasion. The 5-year survival rate of stage Ⅰ gastric cancer patients with vascular invasion was significantly lower than that without vascular invasion (P < 0.01). Conclusion Gastric cancer patients with poor differentiation, deep invasion, lymph node metastasis, nerve invasion and elevated CA724 are more prone to vascular invasion. Patients with stage I gastric cancer at risk of vascular invasion should be treated more aggressively.

Objective To investigate the relationship between mismatch repair (MMR) protein expression and microsatellite instability (MSI) and tumor TNM staging in colorectal cancer. Methods The clinical data of 1351 patients who underwent radical resection of colorectal cancer at the Xijing Digestive Hospital of Air Force Military Medical University from January 2008 to December 2017 were retrospectively analyzed. The MMR and MSI status in patients with different gender, age and TNM staging were analyzed. Results Of the 1351 specimens, 291 (22％) didn't express MMR protein. Univariate analysis showed that there were significant differences in the deletion rates of MSH2, MSH6 and PMS2 between patients ≥60 years old and<60 years old (all P<0.05);there were significant differences in the deletion rates of MSH2 between stage T3 and the other stages (P<0.05); the deletion rates of MLH1, PMS2 among different N stages, and the deletion rates of MSH2 and MSH6 between stage N0 or N1 and the other N stages were significantly different (all P< 0.05); the deletion rates of PMS2 among different M stages were significantly different (P< 0.05). There were significant differences in PMS2 deletion rates among different TNM stages and MLH1, MSH2 and MSH6 deletion rates between stage Ⅱ or Ⅲ and the other stages (all P< 0.05). There was significant difference in MSI positive rates between patients ≥60 years old and<60 years old (P<0.05); there were significant differences in MSI positive rates between stage T3 or T4 and the other T stages, among different N or M stages, and between TNM stage Ⅱ, ⅢorⅣand the other TNM stages (all P<0.05). Conclusions The MMR protein expression and MSI in colorectal cancer patients are closely related to tumor TNM staging. Detection of MMR protein expression and MSI in colorectal cancer patients has certain reference value for judging TNM staging of colorectal cancer. To a certain extent, it can guide the diagnosis and treatment of patients with colorectal cancer and judge the prognosis.

Objective:To investigate the risk factors of lymph node metastasis for patients with colorectal cancer in T 3 and T 4, and to provide a reference for clinical diagnosis and treatment. Methods:The clinicopathological data of 1 112 patients with colorectal cancer in T 3 and T 4 who underwent radical resection of colorectal cancer in Xijing Digestive Disease Hospital from January 2008 to December 2017 were retrospectively analyzed. The correlation between lymph node metastasis status and the clinicopathological factors as well as tumor markers was analyzed. The related risk factors of lymph node metastasis were analyzed by using logistic multivariate regression analysis. Results:Univariate analysis showed that there was no statistically significant difference in the incidence of lymph node metastasis among colorectal cancer patients stratified by gender, age and tumor location (all P > 0.05). The different tumor diameter [<5 cm and ≥5 cm: 37.75% (211/559), 52.26% (289/553), χ2 = 23.666, P < 0.01], general type [infiltration, ulcer, parasol, bulge: 37.04% (20/54), 47.52% (432/909), 34.33% (23/67), 69.51% (57/82), χ2 = 13.787, P = 0.003], degree of differentiation [highly-differentiated, moderately-differentiated, poorly-differentiated: 34.11% (102/299), 49.00% (317/647), 48.80% (81/166), χ2 = 19.771, P < 0.01], mismatch repair deficiency (dMMR) [yes and no: 26.34% (64/243), 50.17% (436/869), χ2 = 43.996, P < 0.01], neurological invasion [yes and no: 48.17% (421/874), 33.20% (79/238), χ2 = 16.954, P < 0.01], vascular invasion [yes and no: 79.16% (338/427), 23.65% (162/685), χ2 = 327.493, P < 0.01] and preoperative carcino-embryonic antigen (CEA) [positive (≥5 mg/ml) and negative (<5 mg/ml): 52.87% (249/471), 39.16% (251/641), χ2 = 20.162, P < 0.01] and CA199 [positive (≥35 U/ml) and negative (<35 U/ml): 59.33% (124/209), 41.64% (376/903), χ2 = 21.465, P < 0.01] had statistically significant differences in the incidence of lymph node metastasis for above stratified patients. Logistic multivariate regression analysis showed that vascular invasion and preoperative CA199-positive were independent risk factors for lymph node metastasis in patients with colorectal cancer in T 3 and T 4 ( OR = 13.006, 95% CI 9.329-17.276, P < 0.01; OR = 2.194, 95% CI 1.513-3.181, P < 0.01), and dMMR-positive was a protective factor for lymph node metastasis ( OR = 0.279, 95% CI 0.190-0.411, P < 0.01). Conclusions:Vascular invasion is the main risk affecting factor for the lymph node metastasis of patients with colorectal cancer in T 3 and T 4. The detection of preoperative tumor marker CA199 can be used as an index to predict the lymph node metastasis of patients with colorectal cancer in T 3 and T 4. To a certain extent, it can provide a reference for the diagnosis and treatment of patients with colorectal cancer in T 3 and T 4.

Objective:To investigate the application prospect of 3D virtual reconstruction and printing technology based on thin-slice CT images in network cloud+dual-track teaching.Methods:A total of 120 medical students who were on probation in The Second Affiliated Hospital of Air Force Medical University from April 2021 to April 2022 were selected as subjects and were randomly divided into experimental group and control group, with 60 students in each group. The students in the experimental group received 3D virtual reconstruction and printing technology combined with network cloud+dual-track teaching, and those in the control group received network cloud+dual-track teaching alone. After 6 months of learning, the teaching effect was compared by closed-book examination, skill operation, speech defense, and questionnaire survey. SPSS 23.0 was used for the t-test and the chi-square test. Results:Compared with the control group in terms of department examination, the experimental group had significantly better scores of theoretical knowledge [(84.25±5.53) vs. (79.43±6.69), P<0.001] and operational skills [(87.68±5.72) vs. (82.97±5.32), P<0.001]. The experimental group had significantly higher scores than the control group in speech [(44.90±2.56) vs. (41.88±2.71), P<0.001] and defense [(45.83±2.62) vs. (43.85±2.56), P<0.001]. The questionnaire survey showed that compared with the control group, the experimental group had significantly higher scores of practical ability, active learning ability, expression ability, practice enthusiasm, and information acquisition ability ( P<0.001). Conclusion:The network cloud+dual-track teaching model assisted by 3D virtual reconstruction and printing technology can significantly improve the objective learning effect and subjective learning initiative of students and has a relatively high value of teaching application and promotion.