A new free-hand pedicle screw placement technique with reference to the supraspinal ligament

Abstract

We sought to compare the safety and accuracy of a new free-hand pedicle screw placement technique to that of the conventional technique. One hundred fifty-three consecutive adult patients with simple fracture in the thoracic or/and lumbar spine were alternately assigned to either the new free-hand or the conventional group. In the new free-hand technique group, preoperative computerized tomography (CT) images were used to calculate the targeted medial-lateral angle of each pedicle trajectory and the pedicle screw was inserted perpendicular to the correspond-ing supraspinal ligament. In the conventional technique group, the medial-lateral and cranial-caudal angle of each pedicle trajectory was determined by intraoperatively under fluoroscopic guidance. The accuracy rate of pedicle screw placement, the time of intraoperative fluoroscopy, the operating time and the amount of blood loss during operation were respectively compared. All screws were analyzed by using intraoperative radiographs, intraoperative triggered electromyography (EMG) monitoring data, postoperative CT data and clinical outcomes. The accuracy rate of pedicle screw placement in the new free-hand technique group and the conventional technique group was 96.3% and 94.2% (P < 0.05), respectively. The intraoperative fluoroscopy time of the new technique group was less than that of the conventional technique group (5.37 seconds vs. 8.79 seconds, P < 0.05). However, there was no statistical difference in the operating time and the amount of blood loss during operation (P > 0.05). Pedicle screw placement with the free-hand technique which keeps the screw perpendicular to the supraspinal ligament is an accurate, reliable and safe technique to treat simple fracture in the thoracic or lumbar spine.

Feasibility Study of Free-Hand Technique for Pedicle Screw Insertion at C7 without Fluoroscopy-Guidance

“…Accurate PS placement in C7 is critical for stabilizing the vertebral segments. Among the three screw types (lateral mass screw, laminar screw, and PS), PS has been recognized as a superior option for posterior stabilization due to its high degree of strength, which can endure segmental motion [ 1 2 11 ]. Several experimental and clinical studies have demonstrated that PS screws can provide more strength for de-stabilized cervical segments compared with other screws [ 1 3 7 ].…”

“…Posterior stabilization procedures with screw-rod systems are frequently used to treat various cervical pathologies in the cervical spine including cervical stenosis, segmental instability, and fracture-dislocation [ 1 2 3 4 5 ]. In the cervical spine, placement of a posterior screw requires a lateral mass screw, laminar screw, and a pedicle screw (PS).…”

“…However, a PS is the firstline selection for posterior stabilization in C7, because the lateral mass of this vertebra is smaller than those of other vertebrae. Thus, C7 is not strong and solid enough to accommodate other screws [ 1 2 6 7 ]. In addition, a laminar screw alone is not strong enough to endure segmental motion [ 1 6 8 9 ].…”

“…In addition, a laminar screw alone is not strong enough to endure segmental motion [ 1 6 8 9 ]. However, the insertion of a PS in C7 is difficult due to its steep convergence angle, the lack of an apparent entry point for screw placement, and the positioning of critical structures near the pedicle, such as the spinal cord and the nerve root [ 1 2 3 4 5 7 10 11 ].…”

“…Finally, the operation time is longer due to the extensive preparation required and the movements of the machine to ensure proper imaging. The problems associated with radiation exposure during surgery have received increased attention by surgeons [ 2 4 5 6 12 ]. These studies have clearly shown that the amount of continuous radiation exposure resulting from fluoroscopic guidance for PS insertion is not negligible.…”