Analysis of surgeon’s line of sight using an optical tracking system with a multifaceted marker device

Abstract

Video-assisted thoracoscopic surgery (VATS) is a widely used technique where operating surgeons alternate between direct vision through minithoracotomy and monitor-aided vision as required. We analyzed surgeons' line of sight to assess their proficiency at using an optical tracking system with a multifaceted marker device. An infrared optical tracking system was developed that is capable of integrating information from a multifaceted marker device and analyzing three-dimensional (3D) dynamic movements including flexion and rotation. Using this system, we analyzed multiple aspects of surgeons' head poses, thereby indirectly identifying their visual line of sight. A multifaceted device comprising 4 surfaces and 4 markers was constructed and attached to surgeons' heads. The surgeons' head motions were tracked using this multifaceted device and videotaped their face while they performed wedge resection. Both data sets were compared. The system could document 98.5% of surgeons' head motions, with a high correlation (<kappa> = 0.935) between data acquired using the multifaceted device and video analysis. An inverse correlation was observed between tumor size and the monitor-viewing time ratio by surgeons in pulmonary wedge resection (R(2) = 0.728). An optical tracking system with a multifaceted device was able to measure 3D dynamic movements of thoracic surgeons. The associated problems of reflection angle and marker shielding were solved. The utility of this device for analyzing surgeons' visual line of sight during VATS was established.