Overview
SEES is a diagnostic procedure which can be used to enhance the clinial swallow assessment by assessing pre- and post-swallowing outcomes in people with dysphagia. SEES involves passing a rigid laryngoscope through the mouth to view the pharynx, larynx, and subglottis before and after swallowing.
Typically, SEES begins with a 'Pre-Swallow Assessment'. The pre-swallow assessment is used to examine pharyngeal and laryngeal anatomy, secretions, vocal fold mobility, and other potentially relevant non-swallowing tasks (e.g., pharyngeal squeeze maneuver, light breath hold, Valsalva maneuver, stroboscopy).
Then, SEES proceeds to the 'Swallow Assessment'. The swallow assessment is completed by: (1) first, presenting the examinee with foods or liquids to eat and drink, (2) then, using the scope to record the examinee externally as they eat/drink and swallow to document number of chews and swallows and to document any instances of coughing or throat clearing, (3) then, using the scope to record oral residue, and (4) re-insert the scope for to visualize post-swallow residue patterns within the pharynx, larynx (penetrant residue), and subglottis (aspirate residue). The Visual Analysis of Swallowing Efficiency and Safety (VASES) can be used to facilitate standardized rating of residue, penetration, and aspiration. Because the scope is not in place during the swallow, it is important that the liquids presented have a 'coating effect', such as presenting water with white dye or using barium water.
SEES was originally published in 2016 (Curtis et al., 2016), with several followup studies having been completed. A 2024 study assessed SEES using relatively affordable (~$50-$400 USD) intra-oral dental cameras in an acute inpatient setting (Vergara et al., 2024). Disposable sheaths can be used on the camera to help facilitate their use between patients (though you would need to verify with infection control if the sheaths, plus cleaning the camera, is permissible). Higher level research is needed, but current data are promising.
SEES Video Demonstration
This video demonstration illustrate myself (James Curtis, PhD, SLP) passing a rigid laryngoscope transorally on Allie Beam, MS, SLP, completing what is known as a Static Endoscopic Evaluation of Swallowing ('SEES').
Here, I begin with a pre-swallow assessment, looking at secretions, pharyngeal/larygneal anatomy, vocal fold mobility and edges, and vibratory parameters. I also attempt to have the patient complete a pharygneal squeeze maneuver, which elicited a gag (totally okay) and therefore could not be determined.
Then, I proceed to trialing a self-selected volume bite size (I record the bite size after) of a graham cracker. I record their chewing patterns and document if a cough/throat clear is observed. Then I record oral residue before visualizing the pharynx, larynx, and subglottis.
Then, I proceed with trials of white-dyed water, including one trial of a self-selected volume, single sip of white-dyed coating water, and two trials of self-selected volume, sequential sips of white-dyed coating water. The size of all self-selected volumes were recorded (off screen) using a digital food scale. Notice how the first trial of the sequential sip penetration was clearly observed.
Potential Benefits and Limitations
SEES is intended to enhance the clinical swallow evaluation and should NOT be used replace FEES or MBS. With that, there are several benefits and limitations that I suspect are present with SEES.
Potential benefits of SEES are (expert opinion - still needs more research):
Because normal foods and drinks can be tested without a scope in situ during swallowing, SEES might exhibit the greatest ecological validity when compared to modified barium swallow studies (whereby, patients are limited to eating/drinking barium or other radiopaque contrasts while in a radiology suite) and flexible endoscopic evaluation of swallowing (whereby, a patient is swallowing while a scope is in their nasal cavity and pharynx during swallowing).
Rigid laryngoscope typically have greater image quality when compare to flexible laryngoscopes (considering same company and same year of model). Therefore, if using a rigid laryngoscope for SEES, as opposed to a low-cost intra-oral dental camera, it is possible that SEES may have greater sensitivity and specificity of the exam. However, this is currently speculative, requires further research, and is likely limited to boluses with coating effects .
SEES is easy and expedient to complete (once the endoscopist is skilled in completing transoral rigid endoscopy).
Potential limitations of SEES are (expert opinion - still needs more research):
It is possible transient events of pharyngeal residue, penetration, and aspiration are missed since the scope is not in place during the swallow. However, current research suggests that, despite this limitation, SEES may still be more sensitive at detecting this impairments when compared to modified barium swallow studies. However, it is important to note this research has been completed using foods and liquids with a coating effect (e.g., barium, heavily concentrated white-dyed water). It is very likely, I suspect, SEES is less sensitive if using liquids without a coating effect.
Technically speaking, performing rigid endoscopy can be more challenging than flexible, and requires more skill from the endoscopic to obtain complete visualization of all structures and to minimize gagging. That said, gagging is common. When it happens, the endoscopist quickly removes the camera, gives the patient a quick break (10 seconds), then re-inserts (repeat as needed).
Additionally, there is no billing mechanism for SEES in the United States of America.
Intra-oral dental cameras are relatively low cost ($50-$400), and have disposable protective sheaths can be placed on the camera and disposed of between patients. It is possible that using the disposable sheaths, and cleaning the camera between uses, would be aide in the camera able to be used between patients. This would need to be verified by your infection control (similar to using a laryngeal mirror, pen light, or anything else that goes near/in a person's mouth). If this is true, then perhaps no billing mechanism is not a deal breaker, given the relatively low cost of the equipment.
It is possible certain custom billing mechanisms might cover SEES. For example, it is possible a -22 modifier might be added to the clinical swallow evaluation or stroboscopic evaluation to indicated enhanced services. It is also possible that the -52 modifier might be added to FEES to indicated reduced services. However, I have not personally tried to use these codes.
Another potentially billing mechanism for SEES is 92700. In an email exchange I had with ASHA about another billing question, they mentioned that 92700 can be used for services such as Manometry, MBS without recording, FEES without recording, SEES, and acoustic/aerodynamic measures of swallowing/cough (not voice). Again, I have not personally not tried to use this code, but this could be an option.
As an aside, we need ASHA and leaders in our field to advocate for the development of billing codes for SEES, and aerodynamic ± acoustic assessments of reflex and voluntary cough! Let's make this happen!
Select References
Curtis, J. A., Laus, J., Yung, K. C., & Courey, M. S. (2016). Static endoscopic evaluation of swallowing: transoral endoscopy during clinical swallow evaluations. The Laryngoscope, 126(10), 2291-2294.
Chang, J., Brown, S. K., Hwang, C., Kirke, D. N., & Goldberg, L. (2021). Predictive values of static endoscopic evaluation of swallowing in adults. Laryngoscope Investigative Otolaryngology, 6(6), 1383-1388.
Meister, K. D., Okland, T., Johnson, A., Galera, R., Ayoub, N., & Sidell, D. R. (2020). Static endoscopic swallow evaluation in children. The Laryngoscope, 130(6), 1590-1594.
Vergara, J., Miles, A., Lopes de Moraes, J., & Chone, C. T. (2024). Contribution of Wireless Wi-Fi Intraoral Cameras to the Assessment of Swallowing Safety and Efficiency (pp. 1-16). American Speech-Language-Hearing Association.