Minimally Invasive Thoracic Pedicle Screws In Basic Research And Clinical Application

1.ObjectiveTo indentify the technical difference between traditional pedicle screw and minimally invasive pedicle screw by measuring relevant data,two techniques were compared in the biomechanical the analysis of the accuracy and the pullout strength of screw placement from 6 specimens of fresh thoracic vertebrae,draw conclusion,guide the clinical.2.Material and method2.1 30 adult patients were obtained,which was consist of 15males and 15 females,none of which were related spine disease,then experienced CT scan,with thickness of 1 mm.measure the angles of screw insertion and the screw path length of traditional approach and minimally invasive approach.2.2 According to the measurement results,two techniques were compared in the analysis of the accuracy and the pullout strength of screw placement from 6 specimens of fresh thoracic vertebrae.2.3 According to the measurement results,30 patients of thoracic vertebral fracture were placed pedicle screws with minimally invasive operation,postoperative CT scan,evaluate the safety of placement.3 Result3.1 Thoracic pedicle screw has two approaches:minimally invasive approach and traditional approach,the angles of screw insertion and the screw path length have statistically significant difference between two approaches.The angle was more bigger and the length is more longer of minimally invasive approach,in T1～11 segment’s measurement of angles,the maximum was in T1,minimum is in Til,decrease gradually form T1～T1l,to T9 negative.The maximum of path length is in T11,minimum is in T1,increase gradually form T1～T11.Each section of the inclined angle and length of nail in a statistically significant difference between men and women.3.2 The accuracy of minimally invasive approach is higher than the traditional approach;the overall maximum axial pullout force of minimally invasive approach is slightly larger than the traditional approach,comparing the two groups,the difference was not statistically significant(P>0.05).3.3 The use of minimally invasive method in 30 patients of thoracic vertebra fracture with screw fixation,small trauma,the point of the needle was easy to confirm,there were no vascular,nerve injury.Postoperative CT scan screw high accuracy 4.Conclusion4.1 The path length of minimally invasive approach was more longer than traditional approach,so the longer screws could be inserted,the screws holding force will be stronger.The Pedicle screw angle of minimally invasive approach was more bigger than traditional approach,so the safe extent of screw insertion angle was present.Notwithstaning the advantage existed in the technique of minimally invasive thoracic pedicle screws,it’s necessary of individualization screw insertion via minimally invasive approach on the basis of preoperative CT image on account of the significant difference both length and angles in gender and the great difference in segments an individuals.4.2 The mechanical stability of minimally invasive approach was bigger than traditional approach.4.3 Thoracic pedicle screw through minimally invasive approach,which is small truma,safe and feasible.