A 48-year-old woman with a history of difficult intubation (Cormack-Lehane Grade 3 on previous anesthesia) is scheduled for thyroid surgery. Awake fiberoptic intubation is planned. Which investigation is most appropriate to confirm the presence of vocal cord pathology and assess laryngeal mobility before the procedure?

## Preoperative Laryngeal Assessment for Awake Fiberoptic Intubation ### Role of Flexible Laryngoscopy **Key Point:** Flexible laryngoscopy is the investigation of choice for preoperative assessment of vocal cord pathology and mobility because it is non-invasive, allows dynamic visualization of cord movement during phonation and respiration, and can be performed in the awake patient without general anesthesia. **High-Yield:** Flexible laryngoscopy in the preoperative setting: - Directly visualizes the larynx and vocal cords in the awake patient - Assesses vocal cord mobility bilaterally (abduction during inspiration, adduction during phonation) - Identifies pathology: paralysis, paresis, fixation, masses, or inflammation - Guides the anesthesiologist on the expected difficulty of intubation - Can be performed in the clinic as part of preoperative workup - Provides functional information essential for planning awake intubation ### Clinical Context **Clinical Pearl:** In a patient with previous Cormack-Lehane Grade 3 intubation, vocal cord pathology (such as paralysis or fixation from thyroid disease) may be the underlying cause of difficult intubation. Preoperative flexible laryngoscopy identifies this and allows appropriate planning of awake fiberoptic intubation technique. ### Comparison of Laryngeal Assessment Methods | Investigation | Awake Assessment | Dynamic Cord Mobility | Invasiveness | Utility in AFI Planning | |---|---|---|---|---| | Flexible laryngoscopy | Yes | Yes | Non-invasive | Excellent — gold standard | | Stroboscopic laryngoscopy | Yes | Yes (vibratory detail) | Non-invasive | Limited — assesses phonatory function, not intubation difficulty | | Rigid laryngoscopy under GA | No | No (patient unconscious) | Invasive | Poor — defeats purpose of awake assessment | | Laryngeal ultrasound | Yes | Limited | Non-invasive | Poor — does not visualize vocal cord movement | **Mnemonic:** **FLEX** — **F**lexible **L**aryngoscopy **E**xplores **X**ynamic cord mobility.