Stokbro Kasper, Bell R Bryan, Thygesen Torben
PhD Fellow and Oral and Maxillofacial Surgical Resident, Department of Oral and Maxillofacial Surgery, Odense University Hospital, Odense, Denmark.
Medical Director, Providence Oral, Head and Neck Cancer Program and Clinic, Providence Cancer Center, Portland, OR.
J Oral Maxillofac Surg. 2018 Dec;76(12):2647.e1-2647.e9. doi: 10.1016/j.joms.2018.08.002. Epub 2018 Aug 16.
It remains unclear to what extent patient-specific printed plates can improve surgical outcomes in orthognathic procedures. This study aimed to quantify the surgical accuracy of patient-specific printed plates in vitro and to compare the results with patients' actual surgical outcomes.
This in vitro study enrolled 20 postoperative orthognathic surgical patients, all treated with inferior maxillary repositioning. The preoperative midfaces were re-created in a 3-dimensionally printed model. The osteotomy and screw holes were placed at prespecified positions using a 3-dimensional guide. The dental segment was repositioned by means of the patient-specific plates. The primary outcome was the mean reposition at 3 dental reference points. The primary predictor variable was the obtained surgical reposition in vitro compared with the virtual surgical plan. Confounding variables were gender, age, occlusion, and bimaxillary surgery. The secondary outcome was surgical accuracy, and the secondary predictor was the in vitro outcomes versus the patients' surgical outcomes. Surgical accuracy was defined as the difference between the obtained reposition and the virtual surgical plan on a continuous scale. The differences were recorded in 3 dimensions according to the positive value of the 3 axes: right, anterior, and posterior. The results were analyzed using mixed-model regression and 1-sample t tests.
In the 20 patients (age, 18 to 64 years; 40% of patients were women), the mean planned reposition was 2.9 mm anterior and 1.8 mm inferior. In all models, the osteotomy edge was rounded off to position the plate in the predetermined position. Overall, the maxilla was positioned 0.5 mm anterior and 0.3 mm inferior to the planned position using patient-specific plates.
The patient-specific plates positioned the maxilla in close approximation to the planned position without surgically relevant differences. The osteotomy edge must be carefully inspected for interference with the patient-specific plates to avoid displacement of the planned maxillary repositioning.
目前尚不清楚定制打印板在正颌手术中能在多大程度上改善手术效果。本研究旨在量化定制打印板在体外的手术精度，并将结果与患者的实际手术效果进行比较。
本体外研究纳入了20例正颌手术后患者，均接受下颌骨复位治疗。术前中面部在三维打印模型中重建。使用三维导向器将截骨和螺钉孔放置在预定位置。通过定制板重新定位牙段。主要结局是3个牙齿参考点的平均重新定位。主要预测变量是与虚拟手术计划相比在体外获得的手术重新定位。混杂变量包括性别、年龄、咬合和双颌手术。次要结局是手术精度，次要预测因素是体外结果与患者手术结果的比较。手术精度定义为获得的重新定位与虚拟手术计划在连续尺度上的差异。根据3个轴的正值在3个维度上记录差异：右、前和后。结果采用混合模型回归和单样本t检验进行分析。
在20例患者（年龄18至64岁；40%为女性）中，计划的平均重新定位为向前2.9毫米和向下1.8毫米。在所有模型中，截骨边缘被修圆以将板放置在预定位置。总体而言，使用定制板时，上颌骨的位置比计划位置向前0.5毫米，向下0.3毫米。
定制板将上颌骨定位在与计划位置非常接近的位置，没有手术相关差异。必须仔细检查截骨边缘是否干扰定制板，以避免计划的上颌骨重新定位发生移位。
