BACKGROUND & AIMS:
:After a failed mandibular osteodistraction, the wrong positioned mandible of a few patients with Pierre Robin sequence returned in the most functional position and regained a proper symmetry, without external intervention. The study aims to explain this self-adjustment and introduce the floating bone phenomenon.The inclusion criteria were severe micrognathia, Fast and Early Mandibular Distraction Osteogenesis protocol, postoperative mandibular wrong positioning, presurgery, immediate postsurgery, and long-term computed tomography scan. Five patients were included. The considered parameters were the distance between mandibular dental centerline and midsagittal facial axis, the rotation of the mandibular body, the magnitude of elongation, and the lowering of the mandibular body.Three patients went from a decentralization >4 mm in the activation phase to a normalization of the said value in the follow-up. In the same period, the interincisal point of 2 patients moved respectively from 0.5 mm on the left and 0.8 mm on the right to 1.2 mm and 1.6 mm on the right, respectively. The rotation of the mandibular body was meanly 25.6° among all patients. The mean value of the distraction was 14.1 mm. A difference of about 4.4 mm between the left and the right side was measured. The lowering of the mandible varied between 2.8 and 12.6 mm.All patients improved their symmetry. Four of them improved in all the measured parameters, while 1 patient presented a worsening in the decentralization of the interincisal point.The floating bone phenomenon could break new grounds in the management of patients with Pierre Robin sequence.
背景与目标:
:在下颌骨牵引失败后,少数具有Pierre Robin序列的患者的下颌骨位置错误,在没有外部干预的情况下恢复了最功能的位置并恢复了适当的对称性。该研究旨在解释这种自我调整并引入浮骨现象。纳入标准为严重微棘突症,快速和早期下颌骨牵张成骨方案,术后下颌骨错误定位,术前,即刻术后以及长期计算机断层扫描。包括五名患者。考虑的参数包括下颌牙齿中心线与矢状面中轴之间的距离,下颌体的旋转,伸长的幅度以及下颌体的降落。三例患者在激活阶段从分散性> 4 tomm转移到了下颌骨。在随访中将所述值归一化。在同一时期,2例患者的切入点分别从左侧的0.5mm和右侧的0.8mm分别移至右侧的1.2mm和1.6mm。在所有患者中,下颌体的旋转平均为25.6°。牵引力的平均值为14.1mm。测量到左侧和右侧之间的差异约为4.4mm。下颌骨的下降幅度在2.8至12.6mm之间,所有患者的对称性均得到了改善。其中有四个在所有测量参数上都有改善,而有1个患者的切齿间点分散性恶化。浮骨现象可能会为Pierre Robin序列患者的治疗开辟新的领域。