三种颧弓缩小术式致咬肌颧肌生物力学变化及并发症的分析

The analysis of complications and changes of biomechanics of masseter muscle and zygomaticus caused by in three kinds of malar arch in reduction malarplasty

目的回顾性分析三种颧弓缩小术式对咬肌颧肌生物力学的影响和产生并发症的原因。方法自2003年5月至2007年8月，采用Baek法冠状切口、Kim法颧颌缝口内入路L型截骨及口内入路颧弓下截骨三种术式对59例女性求美者行面部整形术。术后分析三种术式损伤咬肌颧肌附着点后致面部不对称、面颊部软组织下垂、颧点下移等并发症产生的解剖学和力学原因。结果Baek法冠状切口术，因颧大小肌附着点被剥离，可使而颊部脂肪垫向内下移位，而咬肌附着点被剥离少，力学方向和收缩力量没有大的改变，可能会牵引颧骨骨折端向下移位。Kim法口内入路L型截骨术，因手术设计原因，截骨完成后颧弓滑向内下，由于咬肌强大的向外下方的牵引力，易造成骨间固定松落，使颧骨端向下移位加重，同时使咬肌颧肌及脂肪垫向下移位。颧弓后截骨术的并发症较少，主要是因为对颧骨颧弓的固定系统损伤小，对咬肌颧肌生物力学影响小。结论颧骨缩小无十全十美的术式。手术时不仅要考虑手术的彻底性，同时也应考虑术后因局部肌肉生物力学变化而导致的组织移位等不良后果及其补救措施。

Objective Retrospective analysis of the effect of biomechanics and reasons of complications caused by using three techniques in reduction malarplasty. Methods Since May 2003 to August 2007, using Back＇s coronary incision, Kim＇s malomaxillary suture and L - shape-osteotomy with intraoral approach and osteotomy under zygomatic archwith intraoral approach were adopted for 59 female patients＇ facial plasty. The reasons of complications arising from the mechanics and the anatomical basis, such as facial asymmetry caused by injuried attachment points of masseter and zygomaieus muscle, ptosis of facical soft tissue and the downward movement of malar point in the three surgical procedures were analyzed postoperatively . Results The inside cheek fat pad moved intero - inferiorly because of the zygomatic muscle attachment points were stripped by the method of Back＇s coronary wide incision, however, mechanics direction and strength of contraction were with less change because of the masseter muscle attachment points were stripped less, so the masseter muscle might draw a fractured cheekbone moving downward . As the reasons of operative design of the Kim＇s method, the zygomatic arch slided intero - inferiorly, loosening of fixation between the bones due to strong extro - inferior traction of masseter muscle made , the cheekbones extremities moving downward and made the zygomaticns, masseter muscle and fat pad moving downward at the same time. Osteotomy behind the zygomatic arch was with few complications, mainly due to the small injury in the fixing system of zygomatic arch and less effect of biomechanics of the masseter muscle and zygomaticus. Conclusion There is no perfect technique in reduction ma- larplasty. Surgery is not only to consider the operation complete, but also to consider the cacoethic results of tissue displacement caused by the changes of biomechanics of local muscle and its remedial measures.