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 validate the gross tumor volume (GTV) delineation in head and neck cancer based on magnetic resonance imaging (MRI) or computed tomography (CT) by cross-sectional autopsy,and to provide a basis for clinical evaluation of the two imaging methods.Methods Ten New Zealand rabbits were selected for transplantation of VX2 carcinoma cells,and a head and neck cancer model was successfully established in six rabbits.Each rabbit was fixed and received MRI scan and CT scan in the same body position.Then,they were sacrificed and fixed in gelatin solution (-70℃) for 72 h; all cryopreserved rabbits underwent cross-sectional autopsy using a jig saw,with the same position and sectional thickness as in MRI scan and CT scan,and cross-sectional autopsy images were obtained using a digital single-lens reflex camera.GTVs were separately delineated based on CT,MRI,and cross-sectional autopsy images.The GTVMRI,GTVCT,GTVSA,and volume difference ratios (VDRs) were calculated;two-way classification ANOVA and paired t-test were used for difference analyses.Results The mean values of GTVMRI,GTVCT,and GTVSA were 8.20 ± 2.56,8.40 ± 2.20,and 8.11 ± 2.88 cm3,respectively,without significant differences among them (F =0.06,P =0.943).The mean values of VDRMRI-SA and VDRCT-SA were 0.180 ± 0.060 and 0.309 ± 0.091,respectively,with a significant difference between them (t =7.49,P =0.001).Conclusion The GTV delineation based on MRI is more accurate than that based on CT in head and neck cancer.

Objective To sum up the experience in the diagnosis and treatment of pancreatic duct stone developed as a result of long-term chronic pancreatitis. Methods The clinical data of 11 patients with pancreatolithiasis treated in our hospital from 1996 to 2002 were retrospectively analyzed. Results The main clinical manifestations included abdominal pain, back pain as well as exocrine and endocrine functional disturbance. The disease can be diagnosed by B-mode ultrasonography, CT and ERCP. Nine of 11 cases were treated by pancreaticojejunostomy, 1 case suffering from concurrent carcinoma of the head of the pancreas received pancreaticodudenectomy and 1 case underwent distal pancreatetomy. Ten patients who were followed up were free of pain . Conclusions B-mode ultrasonography is the best choice for the diagnosis of panceatolithiasis, and pancreaticojejunostomy should always be attempted for cases with duct dilatation .

Objective To evaluate surgical management of pancreatic duct stones.Methods From 1997 to 2007, 24 cases of pancreatic duct stones underwent surgical treatment, the clinical data were retrospectively analyzed. Results In this study, 17 cases underwent lithotomy by longitudinal pancreatic duct incision, Roux-en-Y anastomosis(side-to-side) of pancreatic duct to jejunum, extra drainageof the main pancreatic duct was done in two cases, hepaticojejunostomy in three cases, pancreaticcystojejunostomy in one case. One case suffered from postoperative bleeding at pancreatic ojejunostomy, one from stress ulcer, and both were cured by conservative treatment. Three cases underwent pancreaticeduodenectomy, anastomosis bleeding occurred in one patient, and was cured by conservative method. One case underwent duodenum-preserving resection of the head of the pancreas, 2 cases underwent distal pancreatectomy, one case underwent lithotomy by pancreatic duct incision and primary closure, no postoperative complications occurred among those patients. 21 cases were followed up, results were excellentin 17 patients. Conclusions Lithotomy by longitudinal pancreatic duct incision, Roux-en-Y anastomosisof pancreatic duct to jejunum is the main and effective surgical procedure, while duodenum preserving pancreatic head resection and lithotomy by pancreatic duct incision and primary closure are also rational for the treatment of pancreatic duct stones.

Objective To analyze the security and effectiveness of the accurate resection and reconstruction of pelvic tumor with computer navigation and to evaluate the feasibility of pelvic ring structure and mechanics reconstruction using finite element analysis.Methors From December 2008 to June 2010,tumor resections assisted by computer navigation technology and pelvic reconstructions with assembly prosthesis designed by finite element analysis were performed in 12 patients with internal hemi-pelvic malignant tumors.There were 8 male and 4 female patients,with the average age of 39.7 years(range,25-53).The malignant tumors involved chondrosarcoma(4 cases),osteosarcoma(2),Ewing sarcoma(2),malignant fibrohistiocytoma(1),and metastatic tumor(3,in which including renal cell carcinoma 1 case,thyroid carcinoma 1,and breast carcinoma 1).According to Enneking staging classification,there were 1 case in Ⅰ A,2 cases in ⅠB,2 cases in Ⅱ A.and 4 cases in Ⅱ B.The local recurrence of tumor and functional results were followed up postoperatively.Results There were no nerves,vessels and pelvic organs injuries intra-operatively.The postoperative X-rays showed that the excised regions were proper to the preoperative schedule and en bloc resections were performed in all patients.All assembly prostheses were in satisfactory position.and the screw fixation was accordance with the finite element biomechanical analysis.All the cases were followed up for average 18.2 months (range,8-26).There were 1 case with local recurrence and pulmonary metastasis,1 case with deep infection,and 1 case with deep vein thrombosis.No prosthesis dislocation,loosening,breaking,and limb length discrepancy occurred in all patients.The average MSTS93 functional score was 70%in all patients at 6 months,and 68 % in 6 patients at 20 months follow.up.Conclusion The resection and reconstruction of pelvic tumor assisted by computer navigation is a safe and effective procedure.The finite element analysis can provide accurate biomechanical guidance to the reconstruction of pelvic ring.

Background:Cold storage and ischemia-reperfusion injury of liver grafts are critical for the prognosis of patients undergoing liver transplantation. Establishing a stable cold storage and reperfusion animal model is a fundamental measure for related studies. Aims:To establish a modified isolated perfused rat liver model for comprehensive assessment of liver grafts in studies on preservation of liver grafts before transplantation. Methods:Twelve Sprague-Dawley rats were randomly allocated into two groups. Livers of rats in control group were retrieved and perfused immediately for 90 minutes without preservation. In experimental group,liver grafts underwent a 30-minute warm ischemia followed by 24-hour cold storage before ex vivo perfusion. The perfusate was collected dynamically for monitoring the levels of transaminases,electrolytes and pH value;the portal vein pressure of liver grafts was measured by pressure sensor,and the hepatic hydrogen peroxide (HPO)level was assessed by microprobe for free radicals. The bile production was recorded after the ex vivo perfusion;meanwhile,the levels of malondialdehyde (MDA)and superoxide dismutase (Cu/ Zn SOD),the histopathological changes and apoptosis of hepatocytes of liver grafts were examined. Results:Compared with the control group,the levels of AST and ALT,the portal vein pressure and the HPO level of liver grafts in experimental group were obviously increased throughout the perfusion. Furthermore,the bile production and level of Cu/ Zn SOD of liver grafts in experimental group were significantly decreased. The histopathological injury and hepatocytes apoptosis of liver grafts were milder in control group. Conclusions:The liver function and antioxidant effect were reduced in warm ischemic and cold preserved liver grafts. The modified isolated perfused rat liver model established in this study is useful for monitoring and evaluation of the cold storage and reperfusion injury in liver grafts.

ObjectiveTo investigate the feasibility and efficacy of using the hepatoduodenal ligament tension-reduced operation (tension-reduced operation in short) for iatrogenic bile duct injury where the bile duct was severely defective. MethodsBetween March 2006 and May 2009, the authors treated 6 patients with iatrogenic bile duct injury (Bismuth type Ⅱ : 5 patients and type Ⅲ : 1 patient). A no. 7 black silk thread was used to hold the hilar plate tissues and the seromuscular layer of the bulbous part of the duodenum closer together and knots were tied. This method brought the porta hepatis and the duodenal bulb closer together and the hepatoduodenal ligament was shortened. An end to end anastomosis could then be made between the two broken ends of the defective bile duct without tension. ResultsSix patients suffered from bile duct injury and they recovered fully after the tensionreduced operation. There was no complication on follow-up. ConclusionsThe tension-reduced operation was efficacious in the treatment of iatrogenic bile duct injury. This technique should be popularized and more widely used.

OBJECTIVETo analyze the risk factors for level Ib lymph node enlargement on CT in patients with nasopharyngeal carcinoma (NPC) and provide clinical evidence for defining the indications of prophylactic level Ib irradiation.

METHODSA total of 435 newly diagnosed NPC patients receiving radiotherapy in Nanfang Hospital in the past 2 years were enrolled in this analysis. The correlations were analyzed with Logistic regression between level Ib lymphadenopathy and the clinical risk factors including T stage, N stage, diameter of level II lymph nodes, submandibular gland involvement, nasal cavity involvement, oropharyngeal involvement, and involvement of 4 or more lymphatic drainage regions.

RESULTSUnivariate analysis showed that level Ib lymphadenopathy were positively correlated with N stage (P=0.023), submandibular gland involvement (P=0.045), and level II lymph node diameter (P<0.001). Multivariate Logistic regression analysis suggested a significant correlation only between the diameter of the level II lymph nodes and level Ib lymphadenopathy (P=0.013).

CONCLUSIONLevel Ib lymphadenopathy is positively correlated with the size of ipsilateral level II lymph nodes in NPC patients.

Carcinoma ; Humans ; Lymph Nodes ; pathology ; Lymphatic Diseases ; epidemiology ; Lymphatic Metastasis ; Nasopharyngeal Neoplasms ; epidemiology ; Neck ; Paranasal Sinuses ; Risk Factors ; Submandibular Gland

Objective:To explore the advantages of the novel individualized 3D printing artificial vertebral body in spine reconstruction and to evaluate its clinical effect.Methods:From January 2017 to December 2018, the 15 patients who underwent total vertebrectomy and spine reconstruction with individualized 3D printing artificial vertebral body were analyzed retrospectively. There were 8 males and 7 females, with the mean age 39.5 years (range: 20-57), including 12 primary tumors and 3 metastatic tumors. According to tumor location and surrounding soft tissue invasion range, simple posterior or combined anterior and posterior approach were used for total vertebral resection, and the defection was reconstructed by 3D printing artificial vertebral body. The operation time, intraoperative bleeding volume, postoperative stability of artificial vertebral body and bone ingrowth of adjacent vertebral body, preoperative and postoperative neurological changes, preoperative and postoperative VAS score, local control and survival of patients were analyzed.Results:The mean operation time was 412.0 min (range: 135-740 min), and the mean blood loss was 4 140.0ml (range: 100-14 000 ml). The mean follow-up time was 23.2 months (range: 12-35 months), and no one loss to follow-up. One case had pleural rupture, one case had cerebrospinal fluid leakage and one case had L5 nerve root palsy. All patients recovered after active symptomatic treatment. Compare with the preoperative VAS score (4.7±1.1), the differences of VAS score at 7 d postoperative and last follow-up (1.6±0.6 and 1.0±0.5) were significantly reduced ( P<0.001). Three patients with Frankel grade C gradually recovered to grade D, and no change were found in grade D and Grade E patients, there was no significant improved at last follow-up. Preliminary bone growth was found between the artificial vertebral body and the adjacent vertebral body 3 months after operation. The bone growth was more obvious at 12 months post-operation, and the artificial vertebral body fused with the adjacent vertebral bodies to form bone integration. At 24 months post-operation, the integration of the artificial vertebral body was more accurate. During the follow-up period, there was no loosening or displacement of the artificial vertebral body and no failure of internal fixation. A case of hemangioendothelioma and a case of epithelioid angiosarcoma died at 33 months and 35 months postoperatively. One patient with chondrosarcoma had local recurrence at16 months post-operation. After treated with arotinib, the tumor did not progress. The other 12 patients had no tumor recurrence or distant metastasis. Conclusion:After spinal tumor resection, individualized 3D printing artificial vertebral body can be used to accurate restoration of spinal continuity, and provide nice interface matching and bone growth between artificial vertebral body and the adjacent vertebral endplates. Moreover, the immediate and long-term stability of the artificial vertebral body can meet the needs of spinal reconstruction.

Coronary heart disease (CHD) is a kind of cardiovascular diseases originated from atherosclerosis (AS), and chronic inflammation is one of the pathological characteristics. The peripheral blood leukocytes, especially mononuclear cells, play an important role in the AS processes. Recently, in a series of Epigenome-Wide Association Studies (EWAS), multiple DNA differential methylation sites in peripheral blood cells were found to be statistically associated with CHD, which suggested that these DNA differential methylation sites might serve as new risk factors for CHD. The recognition of the variant of DNA methylation as a common epigenetic nucleic acid modification in the occurrence and development of CHD, is ongoing. DNA methylation has the potential to become warning biomarkers, which might provide new ideas and evidences for mechanistic studies of CHD.