Tankersley Ashley C, Nimmich Matthew C, Battan Andrew, Griggs Jason A, Caloss Ronald
Resident, Department of Oral and Maxillofacial Surgery, University of Mississippi Medical Center, Jackson, MS.
Chief Resident, Department of Oral and Maxillofacial Surgery, University of Mississippi Medical Center, Jackson, MS.
J Oral Maxillofac Surg. 2019 Aug;77(8):1675-1680. doi: 10.1016/j.joms.2019.03.004. Epub 2019 Mar 14.
Virtual surgical planning and interocclusal splints are commonly used in performing orthognathic surgery. The benefits are well known, but how close do surgeons come to achieving the planned movements? The aim of this study was to answer this question.
This was a retrospective cohort study of patients who underwent maxillary and mandibular osteotomies to correct their dentofacial deformity. The predictor variable consisted of the virtually planned 3-dimensional (3D) positions of the maxillary and mandibular centroids and maxillary central incisor. The outcome variable consisted of the postoperative 3D positions of these points. Absolute differences were calculated using the root mean square deviation. Other variables that could affect the outcome were assessed, which included skeletal classification, osteotomy sequence, and maxillary segmental surgery. Paired t test was used to determine the mean of the error for the outcome variable. A forward stepwise regression test was used to test for associations with the other variables.
This study was composed of 15 patients with a mean age of 19 years. The maxillary incisor was advanced 2.5 to 8 mm. The mean of the error for the maxillary incisor in the anteroposterior dimension was -2.0 mm, which was a statistically relevant under-advancement (95% confidence interval). The anteroposterior error for the maxillary centroid was significantly higher for a 1- than for a 3-piece Le Fort osteotomy (P = .008). Eight patients had under-advancement of more than 50% of the planned movement, which could be clinically relevant.
The maxillomandibular complex was under-advanced. This could be due to surgeon-dependent variables and other factors that are not simulated with virtual planning. This could affect the desired lip and paranasal support. The surgeon needs to take this into account when planning esthetic objectives for surgery.
虚拟手术规划和咬合间夹板常用于正颌手术。其益处众所周知，但外科医生在实现计划的移动方面能有多接近呢？本研究的目的是回答这个问题。
这是一项对接受上颌和下颌截骨术以矫正牙颌面畸形患者的回顾性队列研究。预测变量包括上颌和下颌质心以及上颌中切牙的虚拟计划三维（3D）位置。结果变量包括这些点的术后3D位置。使用均方根偏差计算绝对差异。评估了其他可能影响结果的变量，包括骨骼分类、截骨顺序和上颌节段性手术。使用配对t检验确定结果变量误差的均值。使用向前逐步回归检验来检验与其他变量的关联。
本研究由15名平均年龄为19岁的患者组成。上颌中切牙前移2.5至8毫米。上颌中切牙在前后维度上误差的均值为-2.0毫米，这是具有统计学意义的推进不足（95%置信区间）。对于1块式而非3块式Le Fort截骨术，上颌质心的前后误差显著更高（P = 0.008）。8名患者的推进不足超过计划移动的50%，这在临床上可能具有相关性。
上颌下颌复合体推进不足。这可能归因于依赖外科医生的变量以及虚拟规划未模拟的其他因素。这可能会影响期望的唇部和鼻旁支撑。外科医生在规划手术美学目标时需要考虑到这一点。
