Rigid videolaryngoscope for difficult intubation caused by mandibular tori

Mandibular Tori Limiting Treatment of Carcinoma of the Upper Aerodigestive Tract

Background:

Mandibular tori are a rare cause of difficult direct visualization of the upper aerodigestive tract. In the setting of aerodigestive tract pathology necessitating direct visualization, removal of mandibular tori may be required to facilitate treatment.

Methods:

In the first case, large bilateral symmetric mandibular tori were removed to facilitate access to the anterior commissure and removal of a T1 glottic squamous cell carcinoma (SCC). In the second case, large bilateral mandibular tori were removed to access a markedly exophytic SCC in the right vallecula. Subsequently, the tumor was removed with robotic assistance with excellent exposure.

Results:

Both patients were free of recurrence at last follow-up.

Conclusion:

Mandibular tori are an uncommon cause of difficult direct laryngoscopy. In situations that require direct visualization of the anterior commissure or base of tongue for diagnosis and management of lesions, surgical removal of the tori may be required as in the cases presented here.

Effect of Mandibular Tori on Glottic Exposure During Simulated Suspension Microlaryngoscopy

Objectives:

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.

Methods:

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.

Results:

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.

Conclusions:

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.