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Objective:To review our clinical experience on total pancreatectomy in treatment of pancreatic diseases.Methods:The clinical data of 25 patients with pancreatic diseases who underwent total pancreatectomy at Nanjing Drum Tower Hospital from February 2016 to October 2019 were retrospectively analyzed. The data on general information, surgical methods, postoperative complications, changes in postoperative pancreatic endocrine and exocrine functions and quality of life were analyzed.Results:There were 16 males and 9 females, aged (60.9±9.4) years. Planned selective surgery was carried out in 16 patients while unplanned operations in 9 patients. There were 15 patients with pancreatic neoplasms with 4 patients who received neoadjuvant or conversion therapy, 6 patients with intraductal papillary mucinous neoplasms, 3 patients with chronic pancreatitis and 1 patient with pancreatic neuroendocrine carcinoma. The total postoperative complication rate was 36% (9/25). One patient died in the perioperative period, and one patient underwent a second operation. After 6 months of operation, 2 of 24 patients had died. The remaining patients had a fasting blood sugar of (8.9±1.6) mmol/L, with an insulin dosage of (30.7±10.6) U/d. The average dosage of trypsin was (1.1±0.3) g/d. The quality of life score reached or exceeded the preoperative levels.Conclusions:Total pancreatectomy was safe and feasible for some pancreatic diseases. For patients with pancreatic cancer, its long-term oncological outcomes need further studies.
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Objective To investigate the effects of the thickness of the adhesives(3 M ESPE RelyX ARC)on the internal stress distribution of the IPS Empress Ⅱ full-ceramic crowns by using Finite Element Analysis(FEA).Method A dummy Empress Ⅱ ceramic crown restoration of the mandible right first molar was prepared according to standard dental process.Followed by micro-CT scanning,four 3D numerical models with cement thickness 60,90,120 and 150 μm were established respectively.The models were subjected to four loading conditions and stresses in veneer and core layers were presented.Result Numerical results indicate that when adhesive thickness increases from 60 μm to 90 μm,the maximum principal stress either in veneer or core decreases.However,when thickness increases to 150 μm,stress variation trends differ from adhesives.Conclusions The normal stresses in adhesives remain a low level when the thickness varies from 90 μm to 120 μm,while the shear stress is less sensitive to the thickness when it exceeds 90 μm.There is an optimal thickness which can reduce the tensile stress in the core and veneer.Attention should be paid to the shear strength of the adhesives since the shear stress could cause failure in the adhesive layer.
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Objective To construct three-dimensional finite element model of lumbar spondylolysis,then to verify its validity by comparison of biomechanics in vitro.Method According to the radiological data of a patient with lumbar spondylolysis,the bone and intervertebral disc of L4-S1 were reconstructed by Simpleware software.The lumbar attaching ligaments and articular capsule were added into simulating model by Ansys software.The three-dimensional finite element model of lumbar spondylolysis was finally simulated successfully,and validated by lumbar spondylolysis biomechanical experiment in vitro.Results The reconstruction of digital model contained the bones of lumbar spine which include vertebral cortical bone,cancellous bone,facet joint,pedicle,lamina,transverse process and spinous process,as well as the annulus fibrosus,nucleus pulposus,superior and inferior end-plates.Besides,anterior and posterior longitudinal ligaments,flavum ligament,supraspinal and interspinal ligaments and articular capsule of facet joint are also attached.The model consisted of 281,261 nodes and 661,150 elements.Imitation of spondylolysis is well done in this model.The validity of the model was verified by comparison of the results of biomechanics in vitro which involved in the trends under loading of stress/strain of L4 inferior facet process,L5 superior and inferior facet process,S1 superior facet process and the trends of stress/strain of lateral and medial L4 inferior facet process.Conclusions Three-dimensional model of lumbar spondylolysis is reconstructed using finite element analysis,and can be further used in the research in biomechanics of lumbar spondylolysis.