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  • Robot-Assisted Stereotaxy Minimizes Target Error: A Meta-Analysis of 8,902 Trajectories

    Final Number:

    Sara Thalheimer BA; Ashwini Dayal Sharan MD; Chengyuan Wu MD, MSBmE

    Study Design:

    Subject Category:
    Emerging Technologies

    Meeting: 2018 ASSFN Biennial Meeting

    Introduction: Despite a growing number of frame-based, fiducial-based, and robot-assisted stereotactic methods, accuracy remains the driving force behind stereotaxy. At present, a direct comparison of all stereotactic methods has yet to be performed. The present study serves as a meta-analysis of 26 publications, reporting the overall accuracy of frame-based and skull fiducial-based systems, and further takes into account the influence of robot-assistance.

    Methods: A PubMed search was performed for the following terms: “Leksell,” “Cosman-Robert-Wells,” “CRW,” “NexFrame,” “STarFix,” “ClearPoint,” “NeuroMate,” “ROSA,” “accuracy,” and “error.” No date restrictions were placed. Raw accuracy data was extrapolated and recorded. System-specific accuracy means and standard deviations were calculated; and z-scores were calculated to compare differences between each system.

    Results: Across 24 studies and a total of 8,902 measurements, the average Euclidean target error for frame-based, fiducial-based, and robot-assisted procedures was 1.89 ± 1.12 mm (N = 2249), 1.86 ± 1.03 mm (N = 1630), and 1.72 ± 0.71 mm (N = 5023), respectively. These data yield no statistical difference between frame-based and fiducial-based systems (p = 0.37), however, the use of a robotic system yielded a statistically significant increase in target accuracy (p < 0.001). Furthermore, when examining only clinically-derived measurements, fiducial-based systems demonstrate a statistically significant increase in accuracy over frame-based systems (p < 0.001), with mean target errors of 2.20 ± 1.26 mm (N = 1070) versus 2.47 ± 1.42 mm (N = 449), respectively. Still, robot-assisted procedures were reported to have the greatest accuracy (p < 0.001), with a mean target error of 1.92 ± 0.92 mm.

    Conclusions: There are incremental improvements from frame-based to fiducial-based and from fiducial-based to robot-assisted of 0.28 mm and 0.27 mm, respectively. All systems demonstrated a mean Euclidean target error of <2.5mm and have demonstrated the ability to provide reliable electrode placement.

    Patient Care: Provide objective data regarding the accuracy of different systems to allow well-informed decision making by physicians.

    Learning Objectives: By the end of the session, participants should be able to 1) Critically analyze pre-existing data on stereotactic techniques, 2) Compare and contrast strengths and weaknesses of frame-based versus skull fiducial-based versus robot-assisted procedures, 3) Begin developing a method by which newly-acquired information can be utilized in clinical settings.


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