Introduction: The rising utilization of thoracolumbar pedicle screws beseeches further efforts toward improving the accuracy of their insertion to minimize known complications associated with improper placement. Several studies have illuminated deficiencies in breach detection using conventional tactile techniques. Endoscopic-assisted pedicle screw placement has been presented previously in animal models and human patients. However, to our knowledge this technique has not been re-examined in the past 17 years. Improvements in endoscope technology, availability, and surgeon training warrant revisiting intraosseous pedicle trajectory endoscopy as a technique to directly visualize cannulated pedicles and assess the risk of complications prior to screw placement.

Methods: Twenty-six thoracolumbar pedicles were cannulated with a gear-shift probe followed by sharp tap in an adult cadaveric specimen. All trajectories were probed manually with a ball-tipped probe followed by endoscopic investigation with a 4 mm rigid zero or thirty degree endoscope.

Results: Visualization of normal pedicle trajectories and cortical wall breaches were excellent (figure 1). All palpable breaches were readily detectable by endoscopy (figure 2). Endoscopy excelled at evaluating the severity of breaches and for permitting unequivocal comprehension of complex trajectories with multiple pathways stemming from a common entry point (figure 3).

Conclusions: Endoscopic assistance holds potential to increase safe and accurate placement of thoracolumbar pedicle screws with minimal resource utilization. More extensive clinical trials are warranted.

Patient Care: Improved sensitivity for detection of improper pedicle cannulation will reduce known risks associated with pedicle screw misplacement.

Learning Objectives: Transosseous exploration of pedicle trajectories has not been described since the advent of HD endoscopy; furthermore, data has emerged illuminating insensitivity in the traditional blind tactile technique used to explore pedicle trajectories. Endoscope techniques should be tested and optimized for pedicle trajectory exploration either routinely or for challenging cannulations.

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