The Animal Experimentation On Porcine Scoliosis Model And The Direction Of Scoliosis

Purpose：To observe the effect exerted by the internal fixation system of titanium wireon the morphological development of spine by means of animal experiment and tomake a preliminary study on the direction of scoliosis.Method: Prepare15domestic and one-month-old pigs, including8male pigs and7female ones; divide them into three groups at random;Group A is the sham-operatedgroup, in which the pigs are simply incised and shown the vertebral part without theinternal fixation; Group B is the group with the internal fixation of titanium wire (nointraoperatie spinal bending), placing the internal fixation system of titanium wirewithout intraoperatie spinal bending and causing no immediate postoperative scoliosis;Group C is the group with the internal fixation of titanium wire (spinal bendinggroup), placing he internal fixation system of titanium wire with intraoperatie spinalbending and showing15-25°cobb postoperative scoliosis; Analyze the ration of thechanged angle between intervertebral disc and vertebral wedge and the total cobbangle on the immediate postoperation, four weeks and eight weeks after operation anddiscuss the causes for the direction of scoliosis.Results: In Group B,C, the ratio between the changed angle of vertebral wedge andthe total cobb angle gradually increases, the ratio between the changed angle ofintervertebral disc and the total cobb angle gradually decreases. The change betweenvertebral body and intervertebral disc wedge on all experimental pigs decreases fromtop vertebral area to both sides. When the operative finish instantly，cobb angle ismost consist of intervertebral disc(Group B: no scoliosis; Group C:91%);8weeksafter operation, cobb angle is the wedge change of vertebral body(Group B:73%;Group C:69%). All the five experimental pigs in Group B bend in the same directionand all the four experimental pigs in Group C bend in the opposite direction (structural scoliosis).Conclusion: Fix on single side, asymmetric tie-down can cause early-onset scoliosismodel in young pigs. The early period after operation, the scoliosis is composed of thewedge change in intervertebral disc; the middle and late period after operation, thescoliosis is composed of the wedge change in vertebral body. The imbalance of loadon both sides and spinal bending while-operation are the important conditions aboutthe direction of Scoliosis.