Influence of different techniques for bilateral sagittal split osteotomy on the fracture pattern of the mandibular ramus in the context of orthognathic surgery: a cadaver study

错(牙合)的表现是多方面的，取决于各种影响因素，常伴有咬合和关节功能障碍。通过手术干预，可以影响和改善颌骨关节的位置。双侧矢状劈开截骨术(BSSO)是治疗这些复杂病例的首选手术方式。最常见的并发症是严重的劈裂(定义为下颌骨近端或远端的不想要的骨折)和手术中损伤下牙槽神经(Ian)导致的神经感觉障碍，这可能会影响患者的日常生活。为了解决这些问题，已经提出了对这项技术以及手术装置的修改。虽然截骨术可以通过钻头、锯子或超声波设备来完成，但大多数下颌骨远端和近端的分离技术都是基于凿子的使用。在这份平面身体调查中，根据标准的手术方案，在下颌角前进行外侧皮质切开术，并在下颌体下缘实施进一步的截骨线的改良技术。截骨术是有选择地用常规钻头或超声波手术进行的，然后用连接到扭力计的凿子进行劈开。这导致了四个研究小组：1)标准程序/演练，2。)标准程序/超声波3.)修改程序/演练，4.)改良方法/超声本研究的目的是探讨双侧矢状劈开截骨术的不同技术和器械对舌骨骨折类型、不良劈裂发生率、下牙槽神经的状态以及劈开所需力量的影响。应该找到一种理想的操作程序，以降低目前的高风险。

The appearances of malocclusions are manifold and depend on various influencing factors and often occur with functional impairments of occlusion and articulation. By surgical intervention, the position of the jaw joint can be affected and improved. The bilateral sagittal split osteotomy (BSSO) is the surgical procedure of choice to treat these complex cases. Therefore, the lower jaw is detached from the base and repositioned.The most common complications are bad splits (defined as unwanted fractures of the proximal or the distal segment of the mandible) and neurosensory disturbances, resulting from injury to the inferior alveolar nerve (IAN) during surgery, which can affect the daily life of patients. Modifications to this technique as well as the surgical devices have been proposed to address these issues. While osteotomy can be done by bur, saw or ultrasonic device, most techniques for separation of the distal and proximal segments of the mandible based on the use of a chisel.In this planed cadaveric investigation, a split procedure is done according to the standard protocol with a lateral corticotomy anterior to the mandibular angle as well as a modified technique implementing a further osteotomy line at the inferior border of the mandibular body. The osteotomy is performed selectively with conventional drills or ultrasonic surgery followed by a split using a chisel connected to a torque gauge. This results in four study groups: 1.) Standard procedure/drill, 2.) Standard procedure/ultrasonic 3.) Modified procedure/drill, 4.) Modified procedure/ultrasonicThe objective of the investigation is the influence of different techniques and devices for bilateral sagittal split osteotomy on lingual fracture patterns, incidence of bad splits, status of the inferior alveolar nerve, and the necessary force for the split. An ideal operation procedure should be found to reduce the current high risk.