A previously intubated 8-month-old infant has failed multiple extubation attempts. Endoscopic evaluation shows circumferential narrowing of the subglottis estimated to involve approximately 80 percent of the cross-sectional area, with no normal mucosa visible in the narrowest segment but a still-detectable lumen. According to the Myer-Cotton classification, what grade of subglottic stenosis is this?
- A Grade III ✓
- B Grade II
- C Grade I
- D Grade IV
Correct answer: A. Grade III
Explanation
The Myer-Cotton endoscopic grading system classifies pediatric subglottic stenosis by percentage luminal obstruction: Grade I up to 50 percent, Grade II 51 to 70 percent, Grade III 71 to 99 percent with no normal lumen detectable but some patency present, and Grade IV complete stenosis with no detectable lumen. An 80 percent narrowing with a patent but abnormal segment therefore falls in Grade III, which typically requires laryngotracheal reconstruction.
Reference: Cummings Otolaryngology: Head and Neck Surgery, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.