Accuracy of minimally invasive percutaneous thoracolumbar pedicle screws using 2D fluoroscopy: a retrospective review through 3D CT analysis

Abstract

Background: In the literature, there is a large variation in the reported misplacement rates of pedicle screws.The use of minimally invasive surgical techniques is increasing and as such there has only been a small amount of data to look at the misplacement rate of percutaneously inserted thoracic and lumbar pedicle screws.Methods: A retrospective analysis of post-operative computed tomography (CT) scans were performed on 108 patients who underwent minimally invasive percutaneously inserted thoracic and lumbar pedicle screws by a single surgeon. Analysis of the screw trajectory using strict guidelines was performed using multiplanar reconstruction CT scan data to determine the accuracy of the pedicle screws.Results: A total of 614 screws were inserted in vertebral levels T2 to S1. Twenty-five (4.07%) screws were considered misplaced having breached the pedicular cortex. Thoracic pedicle screws had a statistically higher misplacement rate than lumbar pedicle screws (14.67% vs. 2.60% respectively, P<0.001). A single screw required replacement (0.16%) and there were no permanent neurological deficits. The misplacement rates were lower than those reported for open screw placement and equivalent to 3D CT navigated misplacement rates.Conclusions: Percutaneously inserted pedicle screws using 2D fluoroscopy offers a safe and accurate option for spinal stabilisation with an extremely low misplacement rate and morbidity. Overall, the low misplacement rates were equivalent and in most cases lower compared to open and computer assisted navigation techniques.However, we would recommend that given a misplacement rate of 14.67% for thoracic pedicle screws that computer assisted navigation may be able to offer further improvements in accuracy.

Navigated robotic assistance results in improved screw accuracy and positive clinical outcomes: an evaluation of the first 54 cases

“…Misplaced screws are not only biomechanically disadvantageous but also carry an increased risk for neurological deficit, vascular damage, and morbidity [1][2][3]. Advances in imaging and navigation such as fluoroscopic guidance have improved the accuracy of screw placement in the spine, yet significantly increased the amount of radiation exposure to the patient, surgeon, and operating room (OR) staff [4,5].…”

Design of a 3D navigation template to guide the screw trajectory in spine: a step-by-step approach using Mimics and 3-Matic software

“…However, the complication of pedicle screw misplacement is concerning with the freehand approach, especially in thoracic and cervical spine region. Winder et al reported that a misplacement rate of thoracic pedicle screws is 14.67% (12). Amiot et al reported…”

Accuracy of Screw Placement in Lumbar Transpedicular Fixation: A Comparative Study between Open and Percutaneous Techniques Using a Novel Classification Model

“…On the other hand, comparison of maldirected screws (classes 2 and 3 collectively) between the two groups confirmed a statistically high significant difference in the number of maldirected screws per patient (P<0.001). Idler et al, 10 Mark et al, 15 and Tsuang et al, 14 reported better results regarding the number of cortical breaches complicating percutaneous lumbar screws placements with an overall accuracy of 98.47%, 97.7% and 94.1% respectively while Spitz et al, 13 reported an overall accuracy of 96.7%. On the other hand, Mohi Eldin et al, 11 reported an accuracy rate that was comparable to that reported in the current study (79.4% versus 81.25 % respectively) regarding the percutaneous group.…”

“…Screw misplacement carries the risk of having an inadequate construct, unintended durotomy and, moreover, an incidence of inadvertent neurological injury of 1%-11%. 5,12,15 Currently, there are three methods for pedicle screw placement: the free hand, the fluoroscopy guided open and the percutaneous techniques with the fluoroscopy guided open technique being the most frequently used one. 3,7,16 The traditional open technique has been always believed to have the disadvantage of extensive paraspinal muscles dissection and retraction for exposure of the necessary bony landmarks that may be a direct cause of more blood loss and a prolonged postoperative hospital stay and recovery time especially from pain.…”

“…4 Today, the percutaneous technique is gaining more popularity for treatment of an expanding variety of spinal pathologies. 6,13,15 However, the lack of direct visualization of bony landmarks and tactile feedback may be considered a challenge for accurate screw placement that can be, in part, overcome by the inevitable increased use of image guidance with its inherent risk of higher radiation exposure. 5 Despite being reported safe and accurate, percutaneous pedicle screw insertion is still being investigated in comparison to the traditional open technique.…”