Flexible Endoscopic Evaluation of Swallowing (FEES): Technique and Interpretation

  • Unnikrishnan K. Menon


The inspection and evaluation of the interior of body cavities improved by leaps and bounds with the advent of the rod lens and optical fibre systems. Over the last few decades, flexible endoscopy using the tensile strength, transparency and homogeneity of glass has further revolutionized this modality. It was in 1968 that Sawashima and colleagues reported the first laryngeal images captured with transnasal flexible scopes [1]. This has now become an almost routine investigation modality in most ENT centres. As such, most ENT surgeons are familiar with the basic technique of this procedure. However, this was almost always used merely for a closer look at the structure of the larynx and to diagnose any organic lesion or neuromuscular dysfunction. Flexible endoscopic evaluation of swallowing (FEES) has widened the horizons of the use of this instrument. As described by Susan Langmore, FEES has been conceived as a comprehensive evaluation of the swallowing process, inclusive of laryngeal anatomic integrity, motor and sensory functions, ability to swallow and response to prescribed changes in posture and/or diet [2].

Supplementary material

Video 6.1

Showing the setting, arrangements and initial steps of FEES (MOV 161350 kb)

Video 6.2

Left vocal fold paresis with a phonatory gap. A notable finding is the thick, mucoid secretions pooled in the left pyriform fossa, overflowing into the interarytenoid and post-cricoid areas. The secretions almost resemble the standard ice-cream bolus in look and thickness! There is no entry into the larynx. This was a case of lateral medullary stroke (MOV 59556 kb)

Video 6.3

The scope tip is gently brought into contact with the right arytenoid, resulting in reflex elevation and closure, indicating active laryngeal sensation. There are no other findings (MOV 54674 kb)

Video 6.4

FEES in a case of cerebellar stroke, where the patient reported ‘difficulty in swallowing’, without true dysphagia or aspiration. The main finding was a coiled NGT. The mild pooling in left pyriform fossa was cleared by head and neck tilt. The culprit was the NGT itself, which could be picked up by FEES. Removal resulted in resolution of the symptom (MOV 111400 kb)

Video 6.5

The scope tip is held in the nasopharynx. After the bolus is administered into the oral cavity, the patient has started to attempt swallowing, but is unable to complete the oral stage. This is evidenced by the corresponding excursions of the soft palate and Passavant’s ridge with each swallow attempt. This demonstrates a way in which the oral phase can be indirectly assessed—this being normally out of view in FEES. The present case was of myasthenia gravis, with the patient recovering from a crisis (MOV 214126 kb)

Video 6.6

Biscuit pieces softened by soaking in water has been given as a bolus, to a patient with the complaint of difficulty in swallowing solids. Significant residue can be noted in the valleculae and right pyriform fossa. Multiple attempts were needed to complete this residue. This is an example of pharyngeal stasis, likely due to the delayed pharyngeal trigger (MOV 85110 kb)

Video 6.7

The case of post total thyroidectomy with documented bilateral vocal cord immobility on the second postoperative day. There was also suspicion of aspiration. FEES did on the sixth postoperative day: Note the obvious phonatory gap, with recovering vocal cord mobility, but absolutely no penetration or aspiration. NGT was removed the next day (MOV 149224 kb)

Video 6.8

The pre-swallow stage of FEES reveals the collected saliva/secretions are dripping down between the interarytenoid level and also onto the false cords. This constitutes laryngeal penetration, further evidenced after the administration of ice-cream bolus. This was a case of recovering pontine stroke (MOV 91030 kb)

Video 6.9

Post-operative right-sided carotid body tumour excision with damage to superior and recurrent laryngeal nerve. FEES demonstrates the bolus is dripping into the larynx up to the level of vocal folds—aspiration. The patient was able to cough out (on command) (MOV 55656 kb)

Video 6.10

A significant amount of pooled secretions and frank aspiration seen in this FEES recording, in a bedridden patient with bilateral cerebellar and brainstem infarcts, posterior fossa decompressive craniectomy done and on tracheostomy. The late oropharyngeal stage is also hinted at by the gradual progress of bolus from above (MOV 121853 kb)

Video 6.11

The case of right vocal fold palsy, post-neck surgery, with resultant weak voice and cough during the swallow. Laryngoscopy showed phonatory gap with saliva gradually trickling into the larynx, as the patient was phonating. So, FEES was done: ice-cream bolus was given. Significant pooling saw in the right PF—unable to clear despite multiple swallows—resulting in laryngeal penetration (secondary). Good cough reflex. No aspiration noted. Patient instructed positional manoeuvre while swallowing—chin tuck and head tilt to right—immediately cleared the residue. Repeated bolus was given with the above manoeuvre—only minimal residue at the first swallow—followed by clearance at the second swallow (MOV 188860 kb)

Video 6.12

FEES in a case of lateral medullary stroke, post-stroke 3 weeks: persistent residue in the post-cricoid area only. Recording three to four distinct swallow attempts, all failing to clear the waste. Interpretation is cricopharyngeal spasm. There is no overflow (secondary) penetration (MOV 215591 kb)

Video 6.13

FEES did in the same patient as in Video 6.9, about 6 weeks post-op. Patient has been taught chin tuck and supraglottic manoeuvre. A careful look at this video shows the distinct control of laryngeal penetration (bolus held firmly at the interarytenoid level) and the split-second opening of the cricopharyngeal sphincter for the swallow (MOV 59063 kb)


  1. 1.
    Unnikrishnan K, Menon C. A historical review of laryngology. In: Nerurkar NK, editor. Textbook of laryngology. New Delhi: Jaypee Brothers Medical Publishers; 2017. p. 7.Google Scholar
  2. 2.
    Langmore SE. Endoscopic evaluation of oral and pharyngeal phases of swallowing. GI Motility Online; 2006.Google Scholar
  3. 3.
    Logemann JA. Preface. In: Berman D, editor. Evaluation and treatment of swallowing disorders. 2nd ed. Texas: Pro Ed; 1998. p. 5.Google Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  • Unnikrishnan K. Menon
    • 1
  1. 1.Department of ENT, Amrita Institute of Medical Sciences and Research CentreAmrita Vishwa VidyapeethamKochiIndia

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