Krenkel C
Department of Oral and Maxillofacial Surgery, State Hospital of Salzburg, Salzburg, Austria.
Atlas Oral Maxillofac Surg Clin North Am. 1997 Mar;5(1):127-55.
Particularly with true dislocation fractures, nonoperative treatment with maxillomandibular fixation followed by physiotherapeutic exercises leads to poor results, as was proved with axiography and clinical examinations. The main reason for this is the shortening and scarring of the condyloid process and the lack of function of the lateral pterygoid muscle. The condyle with its insertion of the muscle is usually displaced medially and anterially and nearly in touch with the origin on the pterygoid process so that protrusion by the muscle is no longer possible. The physiologic relationship of the lateral pterygoid muscle is restored after reduction of the condyle and osteosynthesis of the condylar neck fracture and the original distance between origin and insertion of the muscle is re-established and is a fundamental necessity for regaining function (Fig. 40). The anchor screw osteosynthesis is a most effective technique with low limitations for its indication. A comparison with plates shows this technique to be very economic because one anchor screw has the effect of at least one five-hole plate with five plating screws. That means a reduction of osteosynthesis implants of up to 80%, which saves a lot of money. On the other hand, the sophisticated technique of an anchor screw osteosynthesis needs some training on the part of the surgeon to get the best results possible. In general, we could realize that the anchor screw osteosynthesis gives a perfect adaptation of the fracture ends with compression also on the inner cortical layer, which with plates is only possible in rare cases. After an osteosynthesis of mandibular condyle neck fractures with an axial anchor-screw there are a few cases with an absorptive process in the fracture interface where the screw migrates in an axial direction with loosening of the osteosynthesis. This effect can be compared with the effect of a dynamic hip screw, which leads to compression of the callus, which speeds up bony union at the expense of shortening the bone. When the same absorption happens using a plate, the fracture ends cannot become sintered and the plate is in danger of fracturing as a result of metal fatigue. Ceipek evaluated 136 patients with mandibular condylar neck fractures treated with axial anchor screw osteosynthesis. Thirty-six of these screws showed signs of migration, but only 3.7% for more than 4 mm. For the migration process there are some important risk factors: difficult repositioning of the proximal fragment, dorsal luxation fracture, indirect method of anchor screw osteosynthesis, narrow condyle neck, no intercuspation in the molar region, no compliance, and disturbance of bone healing. Another stable technique of osteosynthesis should be used if patients show more risk than one risk factor.
特别是对于真正的脱位骨折，采用颌间固定随后进行物理治疗的非手术治疗效果不佳，这已通过轴位片和临床检查得到证实。主要原因是髁突缩短和瘢痕形成以及翼外肌功能丧失。附着有肌肉的髁突通常向内和向前移位，几乎与翼突上的起点接触，因此肌肉无法再产生前伸作用。在髁突复位和髁突颈部骨折骨合成后，翼外肌的生理关系得以恢复，肌肉起点和止点之间的原始距离得以重建，这是恢复功能的基本必要条件（图40）。锚钉骨合成是一种非常有效的技术，其适应证限制较少。与钢板相比，该技术非常经济，因为一枚锚钉的效果至少相当于一块带有五枚钢板螺钉的五孔钢板。这意味着骨合成植入物可减少多达80%，节省大量资金。另一方面，锚钉骨合成的复杂技术需要外科医生进行一些培训才能获得最佳效果。总体而言，我们可以认识到，锚钉骨合成能使骨折端完美贴合，在内侧皮质层也能产生加压效果，而使用钢板时只有在极少数情况下才能做到。在用轴向锚钉对下颌髁突颈部骨折进行骨合成后，有少数病例在骨折界面出现吸收过程，螺钉沿轴向迁移，骨合成松动。这种效果可与动力髋螺钉的效果相比较，动力髋螺钉会导致骨痂压缩，从而加快骨愈合，但代价是骨缩短。当使用钢板出现同样的吸收情况时，骨折端无法烧结，钢板会因金属疲劳而有断裂的危险。Ceipek评估了136例采用轴向锚钉骨合成治疗的下颌髁突颈部骨折患者。其中36枚螺钉出现迁移迹象，但超过4毫米的仅占3.7%。对于迁移过程，有一些重要的危险因素：近端骨折块复位困难、背侧脱位骨折、锚钉骨合成的间接方法、髁突颈部狭窄、磨牙区无咬合、不配合以及骨愈合障碍。如果患者存在不止一个危险因素，应采用另一种稳定的骨合成技术。
