Use Endoscope and Instrument and Pathway Relative Motion as Metric for Automated Objective Surgical Skill Assessment in Skull Base and Sinus Surgery

Background Endoscopic skull base and sinus surgery (ESBSS) is one of the most common surgical procedures, with over 300,000 surgeries performed in the United States yearly, for treatment of neoplasm, cancer, and chronic sinusitis (CRS). Objective assessment of surgical skills helps surgeons with skill improvement and leads to improved patient care; however, it is extremely expensive and requires experts to review surgical video. In many instances, this is prohibitively resource intensive. In this study, we propose an automated objective skill assessments based on instrument and endoscope motion.

Fig. 1

Methods The motion data from five cadaveric sinus and skull base operations were collected with commercial navigation systems (Medtronic S7, Medtronic, Dublin, Ireland). Motion data from the endoscope and the instrument were filtered and the data points outside the scope of the surgical site were removed. The pathway was then defined as the convex hull (the purple polygon in the left figure) that was converted from all remaining points with Delaunay triangulations. The central line of the pathway was defined as the line that minimizes the total distance to all remaining data points. Motion data from the endoscope and the instrument were individually clustered into subsets according to anatomical regions of left/right anterior/posterior ethmoid sinuses, frontal sinus, left and right maxillary sinuses, nasal airway, and sphenoid sinus, as indicated by the colored points in the right figure. Our group has previously shown that this regional organization improves the precision of the skill differentiation. For motion data in each anatomical region, the metrics defined were the deviations of the endoscope and the instrument from the pathway central line, the maximum and the minimum velocity of the instrument with respect to the endoscope, the spectrum of the instrument velocity with respect to the endoscope, the distance between the endoscope tip and the instrument tip, the angles among the instrument, and the endoscope and the pathway central line.

Results The motion data were collected from five cadaveric operations with a commercial navigation system (Medtronic S7), and the comparison between the attending surgeons and the residents showed significant difference in the defined metrics.

Conclusion This article verified the hypothesis that the relative motion patterns between the endoscope and the instruments can objectively indicate surgical skill levels. The proposed method has the potential to be applied to any navigated ESBSS. It has no impact on the surgical procedure, and it only depends on a reliable surgical navigation system. It provides an objective, automated report of skill assessment, which otherwise can be extremely resource intensive to obtain via traditional video review in OSATS.