Soncul M, Bamber M A
Department of Oral and Maxillofacial Surgery, Eastman Dental Institute, University College London Hospitals, University of London, UK.
Int J Oral Maxillofac Surg. 2000 Apr;29(2):86-90.
The aim of this study was to evaluate the reproducibility of the head position for a three-dimensional soft tissue laser scan (lasergraph) using thin-plate splines, for orthognathic surgery planning and follow-up. 60 laser scans of five subjects (12 scans per subject) were obtained at specified intervals. The head was positioned in the lateral view using a spirit level, an engineering device for setting horizontal surfaces, to adjust the Frankfort horizontal plane parallel to the ground. The projection of a narrow beam of longitudinal laser light was used to adjust the axial plane for the frontal view. These scanned images (lasergraphs) were digitised and the co-ordinates of the landmarks recorded. The digitised laser scans were compared using thin-plate splines analysis. The mean difference between the scans due to variations in head position was 0.0135 +/- 0.0109 g x cm2/ sec2 in the lateral view and 0.0090 +/- 0.0054 g x cm2/sec2 in the frontal view. This represents an overall distortion error of less than 2% when following up the surgical change of a typical bimaxillary osteotomy case with 6 mm maxillary advancement and 3 mm mandibular set-back. It is concluded that facial laser scans (lasergraphs) with the Frankfort horizontal plane set using a head rest and spirit level, and the axial plane set using projection of a vertical laser light on the facial midline, are highly reproducible.
本研究的目的是评估使用薄板样条法进行三维软组织激光扫描（激光图像）时头部位置的可重复性，用于正颌外科手术规划和随访。在特定间隔对五名受试者进行了60次激光扫描（每名受试者12次扫描）。使用水准仪（一种用于设定水平面的工程装置）将头部置于侧视图中，以调整法兰克福水平面与地面平行。使用纵向激光窄束的投影来调整正视图的轴向平面。对这些扫描图像（激光图像）进行数字化处理并记录标志点的坐标。使用薄板样条分析比较数字化的激光扫描图像。由于头部位置变化，侧视图扫描之间的平均差异为0.0135 +/- 0.0109 g x cm2/秒2，正视图为0.0090 +/- 0.0054 g x cm2/秒2。对于典型的双颌截骨病例，上颌前徙6 mm和下颌后退3 mm的手术变化进行随访时，这代表总体失真误差小于2%。得出的结论是，使用头托和水准仪设定法兰克福水平面，并使用垂直激光在面部中线的投影设定轴向平面的面部激光扫描（激光图像）具有高度可重复性。
