Related Experiment Video
Updated: Jan 23, 2026
A Spine Robotic-Assisted Navigation System for Pedicle Screw Placement
Published on: May 11, 2020
The Learning Curve of Subaxial Cervical Pedicle Screw Placement: How Can We Avoid Neurovascular Complications in the
Yeon Heo1, Su Bum Lee1, Byung Ju Lee1
1Department of Neurosurgery, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea.
Background:
Despite the biomechanical benefits of subaxial cervical pedicle screw (CPS) placement, possible neurovascular complications, including vertebral artery and nerve root injury, are of great concern. We have demonstrated many times the safety and efficacy of CPS deployments, even when using freehand technology.
Objective:
To analyze the learning curve of CPS placement to determine the number of cases necessary for assuring safe CPS placement and to identify a reasonable accuracy rate.
Methods:
From March 2012 to August 2018, a single surgeon performed posterior cervical fusion surgery using CPS placement on 162 consecutive patients. We classified whole surgical periods, 6 years, into 4 periods. We analyzed the screw breach rate, lateral mass screw conversion (LMSC) rate, and reposition rate. We also compared the CPS placement accuracy in the initial 15, 20, and 30 patients with the other 147, 142, and 132 patients, respectively, to assess the number of procedures necessary to reach the learning curve plateau and to identify a reasonable accuracy rate.
Result:
The total number of planned CPS placements was 979. Our learning curve showed that the breach rate plateaus at 3% to 4%. The necessary numbers for safe and accurate CPS placement during learning curve were 30 patients and 170 screws. None of the patients undergoing CPS developed a neurologic or vascular complication.
Conclusion:
By following our 5 safety steps, the steady state for safety and accuracy can be reached without neurovascular complications even in the initial period of the learning curve.
Related Concept Videos
01:14Avoidance Learning and Learned Helplessness
Avoidance learning occurs when an organism learns that a specific behavior can prevent an unpleasant outcome. For example, a student who receives a bad grade may start studying harder to avoid future poor grades. This behavior persists even when the negative outcome is no longer present. Avoidance learning is powerful because it maintains behavior in the absence of the...
01:14Frustration and Conflict: Avoidance-Avoidance, Double-Approach Avoidance
03:25The Periodic Table
02:33Initiation of Translation
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
02:33Initiation of Translation
01:16Self-Locking Screw
A square-threaded screw jack carrying a load is considered self-locking if the screw retains its position even after the moment applied to it is removed.