Minimally Invasive Percutaneous Internal Fixation With The Sextant Spinal System For Thoracolumbar Fractures And The Anatomical Basis For This Technology

The use of pedicle screws for spinal stabilization has become increasingly popular worldwide. Pedicle screw systems engage all three columns of the spine and can resist motion in all planes. Several studies suggest that pedicle screw fixation is a safe and effective treatment for many spinal disorders. Standard techniques for pedicle screw placement, however, require extensive tissue dissection to expose entry points and to provide for lateral-to-medial orientation for optimal screw trajectory. Open pedicle fixation and spinal fusion have been associated with extensive blood loss, lengthy hospital stays, and significant cost. The purpose of this paper is to describe a new technique and instrumentation for minimally invasive posterior fixation of the thoracolumbar spine by using Sextant Spinal System. ObjectiveTo study the feasibility and application value of percutaneous internal fixation with the Sextant Spinal System in the treatment of thoracolumbar fractures. Methods 1 Materials(1)6 adult carbol-formol-fixed specimens (2) 54 patients with thoracolumbar fractures2 Equipments(1) Disscting instrument(2) Anatomical microscope(3) Vernier caliper(4) Camera(5) Surgical instruments for spinal(6) Sextant Spinal System(7) C-arm3 Methods(1) The origin,branch and distribution of the posterior rami of spinal nerves and the dorsal branches of the segmental artery,vein in the thoracolumbar region were observed on 6 adult carbol-formol-fixed specimens.(2) A total of 54 patients with thoracolumbar fractures underwent posterior pedicle screw internal fixation. They were evenly divided into two groups: minimally invasive group (group A) and traditional open surgery group (group B). Perioperative parameter and Imaging Index were compared between the two groups.(3) Statistics:SPSS13. 0 t-TestResults(1) The posterior branch of the segmental artery in the thoracolumbar region asises lateral to the intervertebral foramen and runs dorsocaudal, inferior to the superior articular process of the vertebral below, and the dorsal branchs of the segmental veins parallel their corresponding arteries. The posterior rami emerge from the intervertebral foramen posterior to the superior articular process of the vertebral below and divide into their terminal medial and lateral branchs. The medial branch of the posterior ramus of the spinal nerve courses dorsally from the lateral aspect of the superior articular process to the root of the transverse, and it is attached to the periosteum by fibers, and the lateral one enters into the deep muscles of the theback.(2) The vertebral height, Cobb's angle and the sagittal index were significantly recovery in the two groups (P<0.01), and there was no significant difference of the Imaging Index between the two groups (P>0.05). However, as compared with the group B, the operative time , hospital stay , operative bleeding and postoperative drainage of group A shortened significantly(P<0.01) . Moreover, one year's follow-up showed the result that all of the 54 patients were found vertebral height loss in some extant, and the loss of vertebral height of group A is more obvious than that of group B.ConclusionsThe percutaneous pedicle screw can we avoid mechanical damage to the posterior ramus of the spinal nerve as well as intraopretive bleeding that may require cautery. The technique of minimally invasive percutaneous pedicle scerws internal fixation with the Sextant Spinal System has the advantages of simpler manipulation, less trauma, less bleeding and rapid recovery and so on. However, it need long - time exposure of X - ray and the loss of vertebral height is more obvious.