Measuring the positional accuracy of computer assisted surgical tracking systems

Area of Science:

• Orthopaedic Surgery
• Biomedical Engineering
• Medical Device Technology

Background:

• Computer Assisted Orthopaedic Surgery (CAOS) technology is rapidly advancing, yet standardized methods for assessing technical performance, specifically positional accuracy, are lacking.
• Independent measurement guidelines are crucial for evaluating the reliability of CAOS systems in clinical settings.

Purpose of the Study:

• To evaluate the positional accuracy of a commercial and a novel CAOS tracking system using newly developed American Society for Testing and Materials (ASTM) International standards.
• To assess the impact of manual versus clamped pointer use on tracking system accuracy.

Main Methods:

• A standardized measurement object model was created based on ASTM guidelines.
• Positional accuracy was evaluated by measuring distances and single-point repeatability for both a commercial (Polaris) and a novel (MicronTracker) system.
• Measurements were taken with the pointer manually held and rigidly clamped to isolate human movement artifacts.

Main Results:

• The novel tracking system exhibited unacceptable distance errors and was disqualified from further testing.
• The commercial system demonstrated accuracy within expected ranges under optimal, clamped conditions.
• Manual pointer use, especially by novices, reduced the commercial system's precision by a factor of ten, indicating significant susceptibility to movement artifacts.

Conclusions:

• The developed ASTM-based guidelines provide a standardized, simple method for independent technical validation of CAOS tracking systems.
• The novel system was deemed unsuitable for clinical use due to high inaccuracy.
• Commercial systems, while accurate under ideal conditions, can experience substantial performance degradation due to manual operation errors, emphasizing the need for technical validation to build user confidence and identify error sources.