Global Spine Journal - 2026-03-10 - Journal Article
Comparison of the Accuracy of Marker Screw-Assisted Pedicle Screw Placement in Thoracic and Lumbar Spine to 3D Navigation: A Randomized Controlled Study.
Khashab MA, Elkhalifa M, Alswat MM, Adas RA
Topics
Key Takeaway
Marker screw technique achieved 94.5% pedicle screw accuracy vs 99.1% for 3D navigation (P=.04), yet met the pre-specified non-inferiority margin with no breach-related neurologic or vascular complications.
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Summary
This non-inferiority RCT compared marker screw (MS) guidance to 3D navigation for thoracic and lumbar pedicle screw placement in 46 patients at a single tertiary center, excluding deformity, tumor, and infection cases. Accuracy was assessed by postoperative CT using the Gertzbein-Robbins classification. MS achieved 94.5% accuracy vs 99.1% for navigation (P=.04), but satisfied the non-inferiority threshold; no neurologic or vascular complications occurred in either group.
Key Limitation
The study excluded deformity, tumor, and infection cases — precisely the high-risk anatomic scenarios where navigation provides its greatest accuracy advantage — limiting generalizability to the most challenging pedicle screw placements.
Original Abstract
Study DesignNon-inferiority randomized controlled study.ObjectivesPedicle screws are the standard for thoracic and lumbar spine fixation. Various guidance techniques exist for optimal screw placement, among which three-dimensional (3D) navigation is regarded as one of the most accurate. The marker screw (MS) technique has been proposed as a method for defining entry points and trajectories. This study compares the accuracy of pedicle screw placement using the MS technique vs that of 3D-navigation.MethodsThe study was conducted in a tertiary center, where patients undergoing thoracic and lumbar spine pedicle instrumentation were assessed. Patients with deformities, tumors, and infections were excluded. Informed consent was obtained. Candidates were assigned to a guidance method by randomly withdrawing a sealed envelope. A computed tomography scan was obtained postoperatively, and the accuracy of pedicle screw placement was assessed and compared between the two groups. The Gertzbein and Robbins system was used to assess pedicle breach.ResultsForty-six patients (23 MS and 23 navigation) received a total of 266 pedicle screws (146 MS and 120 navigation). Baseline demographics and surgical parameters were comparable between groups. Overall accuracy was 94.5% in the MS group vs 99.1% in the navigation group ( P .04). However, MS accuracy was not inferior to navigation and within the non-inferiority margin. No neurologic or vascular complications were attributed to screw misplacement.ConclusionsThe MS technique achieved high placement accuracy with no breach-related complications. Given its safety profile, lower cost, and broader availability, the MS guidance technique represents a viable alternative.