Real-time Image Guidance for Improved Orthognathic Surgery

描述（由申请人提供）：正颌手术用于治疗严重的先天性/发育性颅面畸形和牙面错颌。据估计，超过2.5%的美国人有严重的牙面畸形，需要进行正颌手术。如果不加以纠正，这些错颌会导致心理困扰，咀嚼、言语和呼吸功能受损，影响整体生活质量。在过去的50年里，手术技术得到了改进，刚性螺钉固定减少了术后并发症，提高了成功率，但手术复发仍然存在。大约20%接受下颌骨推进手术的患者，不论是否接受上颌推进手术，术后1-5年出现中度复发。此外，据报道，更复杂的上下颌手术的成功率低至60%。手术复发的一个主要原因是手术中髁突和支的定位不当。患者麻醉时，下颌骨近段（支）的移位引起咀嚼肌的拉伸。咀嚼肌的拉伸最终导致分支回到原来的位置。因此，术中技术或方案可以帮助外科医生引导支/髁复合体回到其生物稳定的术前位置，应减少手术复发并改善治疗效果。该项目的目标是将徒手超声成像技术与实时三维图像配准技术相结合，以帮助口腔颌面外科医生可视化下颌骨近段并将其引导回其稳定的术前位置。我们的假设是一个强大的手术导航系统，具有实时术中可视化能力，将提高正颌手术的疗效和安全性。第一阶段的具体目标是(a)为正颌手术计划、导航和可视化开发、原型和测试算法，以及(b)将算法组件集成到完整的超声引导导航软件系统中，并使用假体评估系统。在第一阶段的可行性论证后，我们会完善系统，并在第二阶段进行广泛的研究。

DESCRIPTION (provided by applicant): Orthognathic surgery is used to treat severe congenital/ developmental craniofacial anomalies and dentofacial malocclusion. It is estimated that over 2.5% of the US population has severe dentofacial deformities requiring orthognathic surgery. Left uncorrected, these malocclusions can lead to psychological distress, impaired masticatory, speech and respiratory functions affecting the overall quality of life. Surgical techniques have improved over the past 50 years with rigid screw fixation decreasing post-operative complications and improving the success rate, yet surgical relapse still occurs. Approximately 20% of patients who had mandibular advancement surgery, with or without maxillary advancement surgery, experience moderate relapse 1-5 years after surgery. In addition, the success rate for more complex maxilla-mandibular surgery is reported to be as low as 60%. A principle component responsible for surgical relapse is due to improper positioning of the condyle and ramus during surgery. The displacement of the proximal segment of the mandible (ramus) produces a stretching of the muscles of mastication while patient is anesthesized. The stretch of the mastication muscles leads eventually to a relapse of the ramus to its original position. Therefore, intra-operative technique(s) or protocol that can assist surgeons in guiding the ramus/ condyle complex back into its biologically stable pre-operative position, should reduce surgical relapse and improve treatment outcomes. The goal of this project is to incorporate freehand ultrasound imaging technology with real-time 3-D image registration techniques to help Oral Maxillofacial Surgeons visualize the proximal segment mandible and guide it back into its stable pre-operative position. Our hypothesis is that a robust surgical navigation system with a real-time intra-operative visualization capability will improve the efficacy and safety of orthognathic surgery. The specific aims of phase I are (a) develop, prototype, and test algorithms for orthognathic surgery planning, navigation and visualization and (b) Integrate the algorithmic components into a complete Ultrasound-guided navigation software system and evaluate the system using a phantom. Following the Phase I feasibility demonstration, we will refine the system and conduct an extensive study in Phase II.