Effect of mandibular tori on glottic exposure during simulated suspension microlaryngoscopy

Simon R Best, James B. Kobler, Aaron D. Friedman, Anca M. Barbu, Steven M. Zeitels, James A. Burns

Research output: Contribution to journalArticle

Abstract

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 (12° to 28°), 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.

Original languageEnglish (US)
Pages (from-to)188-194
Number of pages7
JournalAnnals of Otology, Rhinology and Laryngology
Volume123
Issue number3
DOIs
StatePublished - 2014
Externally publishedYes

Fingerprint

Tongue
Suspensions
Mandible
Larynx
Intubation
Skull

Keywords

  • Difficult airway
  • Difficult intubation
  • Direct laryngoscopy
  • Glottis
  • Laryngoscope
  • Larynx
  • Mandibular tori
  • Suspension microlaryngoscopy
  • Vocal fold

ASJC Scopus subject areas

  • Otorhinolaryngology

Cite this

Effect of mandibular tori on glottic exposure during simulated suspension microlaryngoscopy. / Best, Simon R; Kobler, James B.; Friedman, Aaron D.; Barbu, Anca M.; Zeitels, Steven M.; Burns, James A.

In: Annals of Otology, Rhinology and Laryngology, Vol. 123, No. 3, 2014, p. 188-194.

Research output: Contribution to journalArticle

Best, Simon R ; Kobler, James B. ; Friedman, Aaron D. ; Barbu, Anca M. ; Zeitels, Steven M. ; Burns, James A. / Effect of mandibular tori on glottic exposure during simulated suspension microlaryngoscopy. In: Annals of Otology, Rhinology and Laryngology. 2014 ; Vol. 123, No. 3. pp. 188-194.
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abstract = "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 (12° to 28°), 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.",
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AU - Friedman, Aaron D.

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AU - Zeitels, Steven M.

AU - Burns, James A.

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KW - Suspension microlaryngoscopy

KW - Vocal fold

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