Objective to determine the modulus of elasticity (E) of small intestinal submucosa (SIS), a new biological graft material. Methods The longitudinal tensile testing was performed on 21 specimens of canine jejunum with the electronic material test machine. Results Stress (σ)strain (ε) data were obtained. It was found that the stress (σ)strain (ε) data fitted the expressionσ＝Kεα very well, the mean correlation coefficients R2 was0.991 6.Then the expression of the modulus of elasticity (E) of SIS was E=K1/ασ1-1/α. The mean values of α and K were 3.966 9 and 374.55，so E=4.3992σ0.75. Conclusion The modulus of elasticity was found to increase with increasing stress. The variations law is similar to that of the vessels. Furthermore when σ is 001333 MPa(100 mmHg),E is about 0.16 MPa, which is similar to that of the vessels.
Objective To establ ish sophisticated three-dimensional finite element model of reconstructing the whole pelvis and defects in pelvis caused by the resection of periacetabular tumor, and to research the stress distribution regularity ofthe pelvis reconstructed by the fibular transplantation through three different internal fixation techniques. Methods The CTdatasets including L3 to middle-femur, unilateral fibular and internal fixation system from 1 healthy 35-year-old male volunteer were collected to establ ish finite element models of reconstructing the pelvis after the resection of periacetabular tumors through 3 different internal fixation means, namely fibular with plates, pedicle-rods and sacral-il iac rods. Bilateral leg standing position was simulated, then vertical load of 500 N was imposed on the surface of L3, the stress distribution regularity of reconstructed pelvis, transplanted fibular and internal fixation system were evaluated. Results The finite element models of the pelvis reconstruction after resection of periacetabular tumors were establ ished. The stress concentration of transplanted fibular was extremely high in the vicinity of the host junction sites. For the three internal fixation systems, the connection between steel plate and screw or between titanium bar and screw inclined to have stress concentration; and when the titanium bar was adopted to reconstruct, the transplanted fibular and the healthy side of femoral neck had less stress concentration, while sacral-il iac rods had the most obvious stress concentration. Conclusion For the reconstruction pelvis, the three fibula transplantation and steel plate internal fixation are consistent with intact state of pelvis in terms of the stress distribution, which is a relatively good method for the treatment of bone defect after periacetabular tumor. The finite element model can be used as a tool for the pelvis biomechanics research.