Modified method of recording and reproducing natural head position with a multicamera system and a laser level

• A new method was used to record and reproduce natural head position.
• The method was based on multicamera system and a laser level.
• The reliability and viability were evaluated via studies on physical model.
• The method was highly reproducible.
• Its accuracy was higher than 2 degrees.

IntroductionAs computer-assisted surgical design becomes increasingly popular in maxillofacial surgery, recording patients' natural head position (NHP) and reproducing it in the virtual environment are vital for preoperative design and postoperative evaluation. Our objective was to test the repeatability and accuracy of recording NHP using a multicamera system and a laser level.MethodsA laser level was used to project a horizontal reference line on a physical model, and a 3-dimensional image was obtained using a multicamera system. In surgical simulation software, the recorded NHP was reproduced in the virtual head position by registering the coordinate axes with the horizontal reference on both the frontal and lateral views. The repeatability and accuracy of the method were assessed using a gyroscopic procedure as the gold standard.ResultsThe interclass correlation coefficients for pitch and roll were 0.982 (0.966, 0.991) and 0.995 (0.992, 0.998), respectively, indicating a high degree of repeatability. Regarding accuracy, the lack of agreement in orientation between the new method and the gold standard was within the ranges for pitch (−0.69°, 1.71°) and for roll (−0.92°, 1.20°); these have no clinical significance.ConclusionsThis method of recording and reproducing NHP with a multicamera system and a laser level is repeatable, accurate, and clinically feasible.