Surgical safety of cervical pedicle screw placement with computer navigation system

Abstract

Cervical pedicle screw (CPS) may be the biomechanically best system for posterior cervical segmental fixation, but may carry a surgery-related risk. The purpose of this study was to evaluate the safety of CPS placement using computer navigation system for posterior cervical instrumented fixation and discuss its complication avoidance and management. Posterior cervical instrumented fixation using CPS was performed in a total of 128 patients during the period between 2007 and 2015. Intraoperative image guidance was achieved using a preoperative 3D CT-based or an intraoperative 3D CT-based navigation system. A total of 762 CPSs were placed in the spine level of C2 to Th3. The radiological accuracy of CPS placement was evaluated using postoperative CT. Accuracy of CPS placement using a preoperative 3D CT-based navigation system was 93.6 % (423 of 452 screws) in grade 0; the screw was completely contained in the pedicle, and accuracy of CPS placement using an intraoperative 3D CT-based navigation system was a little bit improved to 97.1 % (301 of 310 screws) in grade 0. CPS misplacement (more than half of screw) was 3.3 % (15 of 452 screws) using a preoperative 3D CT-based navigation system, and CPS misplacement (more than half of screw) was 0.6 % (2 of 310 screws) using an intraoperative 3D CT-based navigation system. In total, 38 screws (5.0 %) were found to perforate the cortex of pedicle, although any neural or vascular complications closely associated with CPS placement were not encountered. Twenty nine of 38 screws (76.3 %) were found to perforate laterally, and seven screws (18.4 %) were found to perforate medially. Image-guided CPS placement has been an important advancement to secure the safe surgery, although the use of CPS placement needs to be carefully determined based on the individual pathology.

Accuracy of a patient‐specific 3D printed drill guide for placement of cervical transpedicular screws

“…These results are comparable to those reported in the human literature (Table 3). [16][17][18][19][20][21][22][23][24] The cause of the 3 grade 1 vertebral canal breaches in this series is unknown. In the current study, locking screws were selected to maximize core diameter and therefore strength for a given thread diameter in comparison to cortical screws.…”

“…As more procedures are performed with this new 3D PDG system, the accuracy of CPS placement and associated patient outcome will be determined. 19,29 All measurements were performed by the same individual to maintain consistency throughout the study. CT was selected over radiography for its documented superior accuracy in assessing screw penetration into the vertebral canal.…”

“…For each vertebra, a virtual drill guide (VDG) was created; the contact surface of each VDG was constructed as an inverted virtual representation of the ventral surface of that vertebra, such that the guide would fit securely onto that Conventional fluoroscopy-guided 13-55.1% 16,18,27,28 Computed tomography-based CAS 2.9-12.5% 16,17,19,29 3D patient-specific drill guide (3D PDG) 2.4-6% 22,23,30 F IGUR E 1 Sagittal image of C4-C7 virtual vertebral models within the computer-aided design software…”

“…Navigational aids such as computer assisted surgery (CAS) or 3-dimensional patient-specific drill guides (3D PDG) are widely accepted in human surgery as conferring a higher degree of accuracy and safety for CPS placement, compared to free-hand and conventional fluoroscopic techniques (Table 1). [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] CAS is currently the most widely used navigation technique. 31 However, 3D PDG technology now rivals CAS by allowing preoperative planning of pedicle screw trajectories and providing rigidly conforming templates for drilling the pilot holes.…”

Navigation an der Halswirbelsäule

“…Alle gängigen konventionellen Versorgungsformen können auch navigiert durchgeführt werden. Für die dorsale Stabilisierung konnte eine niedrigere Fehllagerate als in konventioneller Technik nachgewiesen werden [34]. Für die obere Halswirbelsäule existieren ausschließlich retrospektive Studien mit geringen Fallzahlen.…”