Real-time Image Guidance for Improved Orthognathic Surgery

描述(申请人提供)：正颌外科用于治疗严重的先天性/发育性颅面畸形和牙面错牙合。据估计，超过2.5%的美国人口患有严重的牙面畸形，需要正颌手术。如果不加以纠正，这些错牙合可能会导致心理痛苦，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，坚固的螺钉固定减少了术后并发症，提高了成功率，但手术复发仍有发生。大约20%的接受了下颌前移手术的患者，无论是否有上颌前移手术，在手术后1-5年都会经历中度复发。此外，据报道，更复杂的上颌-下颌手术的成功率低至60%。导致手术复发的一个主要因素是由于手术中髁突和升支的位置不正确。当病人麻醉时，下颌骨近端(升支)的移位会引起咀嚼肌的伸展。咀嚼肌肉的伸展最终导致升支复发到其原始位置。因此，术中技术(S)或方案，可以帮助外科医生引导升支/髁状突复合体恢复到术前生物稳定的位置，应减少手术复发，改善治疗结果。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，帮助口腔颌面外科医生可视化近端下颌骨，并将其引导回到手术前的稳定位置。我们的假设是，具有术中实时可视化能力的健壮的手术导航系统将提高正颌外科手术的有效性和安全性。第一阶段的具体目标是(A)为正颌外科计划、导航和可视化开发、原型和测试算法，以及(B)将算法组件集成到一个完整的超声导航软件系统中，并使用体模对该系统进行评估。在完成第一阶段的可行性论证后，我们会在第二阶段完善该系统，并进行广泛的研究。

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.