| Objective: To summarize the choice of entrance point and the confirmation of screwangle and depth when minimally invasive thoracic and lumbar pedicle screw，throughthe study of the imaging of open thoracic and lumbar pedicle screw surgery, whichprovide a reliable method for the establishment of the preoperative individualizedplanning for the screw surgery, then to improve the accuracy of minimally invasivesurgery, which minimizes the risks and the complications of the surgery, so as to thisscrew surgery can be better promoted, especially in the grassroots hospitals.Methods: This topic is divided into the following two parts.(1) Study theimaging measurement of thoracic and lumbar pedicle. We select T8-L3dry spine bonespecimens as the object of the study. In accordance with the pedicle screw, we markedthe screw point of thoracic and lumbar, and used the X-ray, CT scan to measure thescrew angle and depth of the vertebral entrance point.(2) A comparative study ofminimally invasive surgery and open surgery. We selected three skeletons specimensand made them simulated cadavers, we used the traditional open pedicle screw in theleft side of the specimens, and performed minimally invasive pedicle screw in theright after determined the entrance point through X-ray.Then we to scan the skeletonsby CT. Finally we compared the penetrated bone cortex amount of this two screwsurgeries with t-test, by observing whether the pedicle screw penetrated the medialwall and the lateral wall of the pedicle, and anterior vertebral cortical bone.Results: The entrance point of the left thoracic T8-T12segments were mainly in10:00in the outer edge of pediculus arcus vertebrae of the X-ray films showed, andthe right thoracic pedicle were mainly in2:00; the entrance point of the L1-L3segment of the left lumbar pedicle were mainly in9:00, and the lumbar pedicle weremainly in3:00. The left abduction angle of the T8-L3segments respectively were7.92±0.32,6.57±0.49,5.65±0.36,5.28±0.23,5.03±0.18,5.21±0.31,6.2±0.45 and9.43±0.47;the right respectively were7.81±0.34,6.61±0.45,5.64±0.39,5.33±0.28,5.01±0.18,5.13±0.31,6.35±0.50and9.47±0.44.And the head inclinationangles of the thoracic T8-L3segments were10-0°, the lumbar were-10-0°. Thescrew channel lengths of the thoracic T8-L3segments and the lumbar respectivelywere40-50mm and50-55mm. The left head tilting angle, the left extraversion angle,the length of the screw channel were respectively compared with the right side by thet-test statistical analysis (P>0.05), there were no significant statistical differences inboth sides. The measured data was quite to the reports in the literature. There was nosignificant difference in the excellent rate of pedicle screw, through the preoperativeCT scan measurement after the minimally invasive pedicle screw and open pediclescrew pedicle screw.Conclusion:(1) The development of individualized preoperative plan through thepreoperative X-ray, CT measurements to obtain accurate angle and depth of thepedicle screw help to accurately guide minimally invasive pedicle screw.(2) Theminimally invasive pedicle screw is a safe, practical and feasible method, and it canbe used clinically to biggest reduce surgical risks and complications. |
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