Battagel J M, L'Estrange P R, Nolan P, Harkness B
Department of Orthodontics, London Hospital Medical College Dental School, UK.
Eur J Orthod. 1998 Apr;20(2):121-32. doi: 10.1093/ejo/20.2.121.
Mandibular advancement splints are successful in managing obstructive sleep apnoea (OSA) in selected subjects. For these to be effective, some improvement in the dimensions of the oropharyngeal airway must occur. Twenty subjects with proven obstructive sleep apnoea were examined using lateral cephalometric radiography and a fluoroscopic technique. Cephalograms were analysed, and assessed for both skeletal and soft tissue abnormalities known to be present in OSA subjects. On the basis of these, a prediction was made as to whether the subject's oropharyngeal airway would increase during mandibular protrusion. From the fluoroscopic sequences, the narrowest antero-posterior dimensions of the post-palatal and post-lingual airways were recorded as the mandible moved from the intercuspal position into maximal protrusion. The changes in airway size were noted and these were compared with the predictions made from the static films. In nine subjects, fluoroscopy indicated that the airway opened well during mandibular protrusion, seven did not improve and in four the changes were minimal. Post-palatally the mean airway increase was 2.6 mm, whilst behind the tongue a mean improvement of 3.1 mm was seen. In all but two instances, the cephalometric prediction agreed exactly with the outcome demonstrated by fluoroscopy. All subjects whose airways clearly increased were correctly identified by the cephalogram alone. Cephalometric features associated with a good airway response to protrusion were a reduced lower facial height, low maxillomandibular planes angle and a high hyoid position, accompanied by a normal anteroposterior relationship of the jaws, relatively normal mandibular body length and soft palate area. The more abnormal the skeletal and soft tissue dimensions, the poorer the prognosis. Thus, whilst a single radiograph could indicate whether a positive mandibular response to protrusion could be expected, where doubt existed, a fluoroscopic analysis could provide a useful adjunct to diagnosis.
下颌前移矫治器对部分阻塞性睡眠呼吸暂停（OSA）患者治疗有效。要使其发挥作用，口咽气道尺寸必须有所改善。对20名确诊为阻塞性睡眠呼吸暂停的患者进行了头颅侧位X线摄影和荧光透视检查。分析头颅侧位片，评估OSA患者已知存在的骨骼和软组织异常情况。据此预测患者在下颌前伸时口咽气道是否会增大。在荧光透视序列中，记录下颌从牙尖交错位移动到最大前伸位时腭后气道和舌后气道的最窄前后径。记录气道大小的变化，并与静态X线片的预测结果进行比较。9名患者荧光透视显示下颌前伸时气道开放良好，7名患者无改善，4名患者变化极小。腭后气道平均增大2.6mm，舌后气道平均改善3.1mm。除两例情况外，头颅侧位片预测结果与荧光透视结果完全一致。仅凭头颅侧位片就能正确识别所有气道明显增大的患者。与前伸时气道反应良好相关的头颅侧位片特征包括面下高度降低、下颌平面角低、舌骨位置高，同时颌骨前后关系正常、下颌体长和软腭面积相对正常。骨骼和软组织尺寸越异常，预后越差。因此，虽然一张X线片可以表明是否预期下颌前伸会有积极反应，但在存在疑问时，荧光透视分析可为诊断提供有用的辅助手段。
