Retmperitoneal ganglioneuroma is a rare neurogenic benign tumor.The prognosis of patients was good when the tumor was completely resected,while the surgical procedure is complicated.In March of 2013,a male patient with complex retroperitoneal ganglioneuroma was treated at the First Affiliated Hospital of Chongqing Medical University.A hypoechoic solid lesion (size,6.5 cm ×4.5 cm) adjacent to the head of the pancreas was detected by color Doppler ultra-sonography 9 months ago,and no any other clinical symptoms were detected.Perioperative abdominal computed tomography and the surgery confirmed that the tumor (size,8.5 cm × 7.5 cm × 4.5 cm) was located beneath the pancreas,encompassing thc ccliac artery,hepatic artery,splenic artery and superior mesenteric artery,surrounding the head and uncinate process of the pancreas,making it impossible to be separated.The tumor was closely connected with the portal vein,superior mesenteric vein,splenic vein and left renal vein.The tumor was separated from the major blood vessels,the body and tail of the pancreas,while the tumor could not be resected from the pancreatic head,and thus tumor resection and pancreaticoduodenectomy were performed.The surgery was extremely diffcult,but the complete removal of tumor was successfully achieved without excision of the major blood vessels and the patient recovered well.

BACKGROUND:The traditional view is that proximal fibular fractures do not require fixation.Others and our research suggest that the proximal fibular structure plays an important role in the stability of the posterolateral structure of the knee joint,and its mechanism of action is worth studying. OBJECTIVE:To investigate the biomechanical effects of proximal fibular fractures on various structures of the knee joint in an extended state. METHODS:Finite element method was used to conduct simulated biomechanical experiments.A healthy young male volunteer was selected to establish a finite element model of the knee joint in an extended state using MRI and CT image data,and four proximal fibular shapes were simulated(Model A:intact,Model B:1 cm fracture below the fibular head,Model C:1 cm tip defect fracture from the proximal end of the fibula to the distal end,and Model D:2 cm bone defect from the proximal end of the fibula).A longitudinal concentrated load of 1 500 N was applied to the femoral shaft to compare and analyze the distribution and changing trend of the maximum equivalent stress and maximum first principal stress of each structure of the knee joint in an extended state under four working conditions. RESULTS AND CONCLUSION:(1)In Model A,the maximum equivalent stress in the tibial cartilage and lateral compartment of the meniscus was greater than that in the medial compartment,while the maximum first principal stress in the tibial plateau and medial compartment of the meniscus was greater than that in the lateral compartment.The maximum equivalent stress of the medial condyle of the femoral cartilage was greater than that of the lateral condyle,and the maximum first principal stress of the medial condyle of the femoral cartilage was greater than that of the medial condyle.(2)Compared to Model A,there was no significant difference in the magnitude and distribution of the maximum equivalent stress and maximum first principal stress in the cartilage and meniscus of Model C.(3)Compared to Model A,the maximum equivalent stress increase amplitude of Model B was in the order of medial tibial cartilage(14.9％),medial condyle of femoral cartilage(13.6％),and medial meniscus(6.6％).The maximum first principal stress increase amplitude was the medial meniscus(11.06％),the medial tibial cartilage(8.65％),and the medial condyle of the femoral cartilage(7.46％).The maximum equivalent stress increase amplitude of the ligament was as follows:popliteal arch ligament(33.2％)>anterior cruciate ligament(21.3％)>fibular collateral ligament(17％)>posterior cruciate ligament(14.3％)>anterior lateral collateral ligament(13.2％)>medial collateral ligament(10.1％).(4)Compared to Model A,the maximum equivalent stress increasing trend of Model D followed the medial tibial cartilage(19.5％),femoral cartilage medial condyle(17.9％),and medial meniscus(9.9％).The maximum first principal stress in sequence was the medial meniscus(14.04％),the medial tibial cartilage(13.03％),and the medial condyle of the femoral cartilage(11.37％).The increasing trend of maximum equivalent stress in ligaments was as follows:anterior cruciate ligament(25.2％)>posterior cruciate ligament(18.9％)>medial collateral ligament(18.5％)>anterior lateral collateral ligament(12.7％).(5)It is suggested that when the knee joint is extended,a 1 cm fracture below the fibular head and a 2 cm fibular tip bone defect have a significant impact on the structure of the medial ventricular cartilage,anterior cruciate ligament,and posterior lateral ligament complex.

Objective To investigate the effects of three-dimensional(3D)screws and circular plates on the biomechanical stability of Sanders ABⅢ calcaneal fractures.Methods Calcaneal computed tomography(CT)and magnetic resonance imaging(MRI)data from a 26-year-old volunteer were collected to establish a 3D finite element model of Sanders ⅢAB calcaneal fracture fixed with 3D screws and circular plates.A longitudinal load of 700 N was applied to compare the variations in the stress,displacement of the bone block,and internal fixation in the different models.Results Under 700 N longitudinal loads,the maximum displacement of the bone block and the maximum stress of the bone block and internal fixation were concentrated at the intersection of the posterior talar articular plane internal fixation and fracture line.The overall displacements of the bone blocks in the 3D screw and circular plate models were similar.Compared with the circular plate model,the maximum and average stresses of the bone block and internal fixation in the 3D screw model were lower,and the displacement and stress changes of the 3D screw model were closer to those of the complete calcaneal bone model.Conclusions In the fixation of Sanders ⅢAB calcaneal fractures,both 3D screw and circular plate fixation method can provide good stability.The biomechanical properties of the 3D screws were better than those of the circular plates,which is consistent with the biomechanical characteristics.

BACKGROUND:Satisfactory clinical results have been achieved in the treatment of Sanders Ⅲ calcaneal fractures by percutaneous compression fixation with three-dimensional frame screws.However,whether the stability of minimally invasive plate internal fixation can be achieved in terms of biomechanics,and the advantages and disadvantages after comparison are still unknown. OBJECTIVE:To investigate the fixation effect of different internal fixation devices on Sanders Ⅲ calcaneal fractures by finite element analysis. METHODS:A finite element model of Sanders Ⅲ calcaneal fracture was made based on CT data of a 26-year-old healthy male volunteer.The calcaneal fracture models were fixed by minimally invasive three-dimensional frame screws and minimally invasive Y-plate.The longitudinal loads of 350 and 700 N were applied respectively.The displacement and stress distribution of the two models were analyzed,and the stability of each model was compared. RESULTS AND CONCLUSION:(1)The peak stress of bone block and implant in the minimally invasive three-dimensional frame screw model was significantly lower than that in the minimally invasive minimally invasive plate model.The average stress of bone block and implant in the three-dimensional frame screw model was also significantly lower than that in the minimally invasive plate model.(2)The maximum displacement of the two models was located at the medial side of the articular surface of the posterior talus,and the maximum displacement of the three-dimensional frame screw model was smaller than that of the minimally invasive plate model.(3)The longitudinal displacement between the anterior fragment and the medial fragment of the minimally invasive plate model was smaller,and the transverse and vertical displacement between the medial fragment and the middle fragment of the three-dimensional group screw model was smaller.(4)It is concluded that both of the two internal fixation models can provide satisfactory fixation effect.The three-dimensional frame screw model can provide better transverse and vertical stability with more uniform stress distribution and smaller comprehensive displacement of bone fragments,while the minimally invasive plate has more advantages in maintaining longitudinal stability.

Xinjiang local liver hydatid disease is an infectious parasitic disease in Xinjiang pastoral areas. Based on the image features, selecting the appropriate distance algorithms to retrieve the image quickly and accurately, different distance algorithms have been induced in this area, which can greatly assist the doctors to early detect, diagnose and cure the liver hydatid disease. This paper compared the performance of different distance algorithms to retrieve the image when using the liver hydatid disease medical image texture features. The results showed that: for the liver hydatid disease medical images retrieval based on gray level cocurrence matrix (GLCM) texture features, the Mahalanobis distance algorithm is superior to other distance algorithms.
Algorithms ; China ; Databases, Factual ; Echinococcosis, Hepatic ; diagnostic imaging ; Humans ; Image Processing, Computer-Assisted ; methods ; Information Storage and Retrieval ; methods ; Tomography, X-Ray Computed ; methods