Subaxial Cervical Pedicle Screw Fixation Through Paraspinal Approach:anatomic And Clinical

Objective:To investigate the feasibility and clinical application of the cervical pedicle screw fixation through intermuscular planes between musculus semispinalis cervicis and musculus semispinalis capitis.Methods:5 adult specimens were selectedfor studing the anatomic features of musculus semispinalis cervicis and musculus semispinalis capitis,show the lateral mass and the deep cervical vascular and carotid nerve and 50 cervical pedicle screw from C3-C7 were inserted through the new approach in the specimens.25 patients randomly divided into two groups,experimental group:12 patients were treated by 49 cervical pedicle screws through this new approach,control group:13 patients were treated by 66 cervical pedicle screws through traditional approach,screw positions and complications were observed.the cervical dorsal rami nerve will be cut off if it stop the vision In the operation.Results:Musculus semispinalis capitis was the main part of the lateral intermuscular,Musculus semispinalis cervicis was the main part of the medial intermuscular.Multifidus and rotator participated in forming the cervical dorsal rami nerve bone fiber tube.Medial and lateral intermuscular tissues were dominated respectively by cervical dorsal medial branch and lateral branch.Deep cervical artery lied in upward branches between the semispinalis capitis and semispinalis cervicis,supplying both sides of the semispinalis.6 screws that was placed in the specimens cut through the pedicle walls.the clinical result,The experimental group:Serew were placed successfully in all 12 patients,unilateral exposure time(min):16.00±4.12,unilateral exposure blood loss(ml):41.00±9.56,Length of incision(cm);6.70± 1.73,no articular ligament complex damaged,less damaged of neck extensor group,abduction angle was easily obtained.2 screws that was placed in the specimens cut through the pedicle walls.The control group:Serew were placed successfully in all 13 patients,unilateral exposure time(min):19.01±5.24,unilateral exposure blood loss(ml):52.03±7.35,Length of incision(cm);9.30±2.38,articular ligament complex and neck extensor group were damaged,abduction angle was hardly obtained.4 screws that was placed in the specimens cut through the pedicle walls.observations of cut or remain the cervical dorsal rami nerve,the cut off group:6 cases without feeling disability,2 cases in mild feeling disability,the remain group 9 cases without feeling disability,3 cases in mildfeeling disability.Conclusion:Primary clinical results show cervical pedicle screw placement through the new approach is safe,feasible,easy and minimally invasive.cut off the cervical dorsal rami nerve had no obvious effect on the feeling of the neck.