Best Simon R, Kobler James B, Friedman Aaron D, Barbu Anca M, Zeitels Steven M, Burns James A
Department of Surgery, Harvard Medical School, and the Center for Laryngeal Surgery and Voice Rehabilitation, Massachusetts General Hospital, Boston, Massachusetts, USA.
Ann Otol Rhinol Laryngol. 2014 Mar;123(3):188-94. doi: 10.1177/0003489414522967.
Mandibular tori have been identified as a contributing factor in difficult exposure during intubation. However, no investigation has measured the effect of mandibular tori on glottic exposure during suspension microlaryngoscopy (SML). The objective of this study was to measure how the size and location of mandibular tori affect glottic exposure during simulated SML at different thyromental distances.
Suspension microlaryngoscopy was modeled on an anatomically accurate skull and larynx with thyromental distances between 6 and 12 cm. Mandibular tori were simulated by protruding screws 5 to 15 mm from the lingual aspect of the mandible. The tori were positioned either 15 mm (anterior) or 25 mm (posterior) from the midline of the symphysis. The glottic exposure for the various-size tori in each location was measured by recording the displacement of the glottiscope tip relative to the most anterior exposure achievable without tori. The glottiscope angle relative to the horizontal plane was measured for each condition.
Mandibular tori of more than 10 mm had a significant impact on glottic exposure. Displacement of the glottiscope tip ranged from 2 to 9 mm for anteriorly placed tori and from 7 to 29 mm for posteriorly placed tori, with larger tori causing greater displacement. Increasing the thyromental distance increased the posterior glottiscope tip displacement regardless of torus size or location. The glottiscope angle increased with larger tori (12º to 28º), but this angle did not change with increasing thyromental distance.
Larger size and more-posterior location of mandibular tori more significantly reduce glottic exposure during SML. The inner table of the mandible is the most relevant anatomic constraint on glottic exposure, which varies with the presence or absence of mandibular tori independent of thyromental distance.
下颌隆突已被确定为插管困难暴露的一个促成因素。然而，尚无研究测量下颌隆突对悬吊式显微喉镜检查（SML）期间声门暴露的影响。本研究的目的是测量下颌隆突的大小和位置如何在不同甲状舌骨距离的模拟SML期间影响声门暴露。
在解剖结构精确的颅骨和喉部上模拟悬吊式显微喉镜检查，甲状舌骨距离为6至12厘米。通过从下颌骨舌侧突出5至15毫米的螺钉模拟下颌隆突。隆突位于距联合中线15毫米（前部）或25毫米（后部）处。通过记录声门镜尖端相对于无隆突时可实现的最前暴露的位移，测量每个位置不同大小隆突的声门暴露情况。测量每种情况下声门镜相对于水平面的角度。
超过10毫米的下颌隆突对声门暴露有显著影响。对于前部放置的隆突，声门镜尖端的位移范围为2至9毫米，对于后部放置 的隆突，位移范围为7至29毫米，隆突越大，位移越大。增加甲状舌骨距离会增加声门镜尖端的后向位移，而与隆突大小或位置无关。声门镜角度随较大的隆突而增加（12°至28°），但该角度不会随甲状舌骨距离的增加而改变。
下颌隆突尺寸越大且位置越靠后，在SML期间对声门暴露的减少作用越显著。下颌骨内板是对声门暴露最相关的解剖学限制因素，其会因下颌隆突的存在与否而变化，与甲状舌骨距离无关。
