A study published on March 12, 2025, has provided fresh insights on improving the accuracy of pedicle screw placements, addressing the common issue of entry point (EP) deviations. This research reveals the advantages of using alternative navigation methods over the traditional planning and alignment (PA) approach.
Pedicure screw placement is fundamental to spinal surgeries, but misplacements due to inaccurate entry points can endanger surrounding neurovascular structures. According to the authors of the article, there is substantial variability in reported misplacement rates, with studies reflecting figures as high as 41%. Therefore, any advancements aimed at reducing errors are incredibly significant.
The study explored the influence of EP deviations, investigating new reference methods designated as the screw tip point (STP) and the midpoint (MP). By utilizing 3D vertebral body models for computer simulations, the research objectively compared the accuracy of these methods against the established PA technique.
The results of the simulations were substantial, showing both the STP and MP methods allowed for significantly more viable screw trajectories, achieving statistically significant results at p < 0.01. "Both new methods showed a significantly larger number of possible screw trajectories in the simulations (p < 0.01)," wrote the authors of the article.
One of the findings highlighted the capability of the STP method to maintain acceptable screw diameters, even when deliberately deviated by 4.5 mm from the optimal entry point. At this level of deviation, the study noted, a perforation-free screw diameter of 4.9 mm could still be achieved, demonstrating the flexibility of the STP method.
To evaluate the performance of both new methods practically, phantom-based evaluations were conducted. This involved six experienced surgeons drilling pedicle screw trajectories on models, with some trials incorporating entry point deviations. The findings from these evaluations were promising. The median maximum screw diameter without perforation was noted as 8.8 mm, along with median metrics illustrating direction differences less than 6 degrees.
More explicitly, the study recorded instances where deviations occurred: 84% of the recorded trials had lateral deviations relative to the intended entry point, with 68% showing cranial deviation. Notably, surgeons were able to achieve acceptable diameters for screw placement, even when deviations of up to 8 mm occurred.
Despite some concerns about the trade-offs between lateral and medial placements, the STP method emerged as the optimal choice due to its ability to adapt to real intraoperative conditions. "The STP method seems to be a feasible alternative to the established, less flexible PA method," concluded the researchers.
While this research contributes to the existing body of knowledge, challenges remain. The study acknowledges the need for conducting trials on real human anatomy to assess the method's effectiveness and safety truly. The authors call for future clinical studies to establish the findings more broadly, underscoring the necessity of enhanced accuracy during pedicle screw placements.
Overall, these promising findings suggest advancements beyond the PA method, offering hope for improved surgical practices and patient outcomes through refined navigation techniques.