Assessment of the Learning Curve for Virtual Surgical Planning in Orbital Fractures

Abstract

Virtual surgical planning (VSP) is becoming more widely used in maxillofacial reconstruction and can be surgeon-based or industry-based. Surgeon-based models require software training but allow surgeon autonomy. We evaluate the learning curve for VSP through a prospective cohort study in which planning times and accuracy of 7 otolaryngology residents with no prior VSP experience were compared to that of a proficient user after a single training protocol and 6 planning sessions for orbital fractures. The average planning time for the first session was 21 minutes 41 seconds ± 6 minutes 11 seconds with an average maximum deviation of 2.5 ± 0.8 mm in the lateral orbit and 2.3 ± 0.6 mm in the superior orbit. The average planning time for the last session was 13 minutes 5 seconds ± 10 minutes and 7 seconds with an average maximum deviation of 1.4 ± 0.5 mm in the lateral orbit and 1.3 ± 0.4 mm in the superior orbit. Novice users reduced planning time by 40% and decreased maximum deviation of plans by 44% and 43% in the lateral and superior orbits, respectively, approaching that of the proficient user. Virtual surgical planning has a quick learning curve and may be incorporated into surgical training.

Keywords: computer aided surgery; maxillofacial trauma; orbital fractures; surgical training; virtual surgical planning.

Figure 1.

A, Example user interface for VSP demonstrating segmented unaffected orbit on the right and the mirrored orbit plan superimposed on the left fractured side. The red markers are fiducial points for intraoperative navigation. B, Coronal view: measurement of maximum deviation of mirrored orbit plan from bone superior (blue double-ended arrow) and lateral (yellow double-ended arrow) orbit. VSP indicates virtual surgical planning.

Figure 2.

A, Exponential fitted regression analysis demonstrated a downward trend in the planning time with subsequent trials. Control: y = 298.04e ^0.0224x. Participants: y = 1204.2e ^−0.114x. R ² = 0.1925. P = .0037. B, The novice users’ average planning times approached a proficient user’s planning times (control). *Within 2 standard deviations; **within 1 standard deviation.

Figure 3.

A, A scatter plot and exponential fitted regression analysis showed improvement in the maximum deviation in the lateral orbit in preoperative plans for orbital fractures with successive trials. Control: y = 1.2774e ^0.011x. Participants: y = 2.4626e ^{− 0.127x}. R² = 0.1393. P = .0149. B, There was no significant difference in the novice users’ average maximum deviation in the lateral orbit compared to the proficient user’s measurements for all the trials. *Within 2 standard deviations; **within 1 standard deviation.

Figure 4.

A, Exponential fitted regression analysis of the maximum deviation in the superior orbit in virtual preoperative plans decreased as the number of created plans by each novice user increased. Control: y = 0.6052e ^−0.061x. Participants: y = 2.2291e ^−0.08x. R ² = 0.1122. P = .0301. B, There was variation in the novice users’ average maximum deviation in the superior orbit compared to the proficient user’s data. *Within 2 standard deviations; **within 1 standard deviation.