A.- PHARYNGOESOPHAGEAL SEGMENT (PES)/UPPER ESOPHAGEAL SPHINCTER (UES)

1.- Definition

The upper esophageal sphincter (UES) is a 2.5–4.5 cm manometric high-pressure zone located between the pharynx and esophagus

Because of its location, this region has also been referred to as the pharyngoesophageal segment (PES)

The cricopharyngeus muscle (CPM) makes up only one component of the PES.

The CPM is not synonymous with the UES and PES

Fig 1: Pharyngoesophageal segment (PES)/Upper esophageal sphincter (UES)

 2.- Anatomic landmarks

Fig 2: Anatomic landmarks

 3.- PES´s Physiology

Swallowing relies on the proper and timely opening of the pharyngoesophageal segment (PES). This opening is facilitated by the relaxation of the cricopharyngeal muscle (CPM), elevation of the larynx, and contraction of the pharyngeal muscles.

Fig 3: PES´s Physiology

B.- QUANTITATIVE AND QUALITATIVE ASSESSMENT OF THE PHARYNGOESOPHAGEAL

SEGMENT (PES)

Fig 4: Quantitative and qualitative assessment of the pharyngoesophageal segment (PES)

1.- Qualitative assessment

1.1.- Evaluation of pre-swallow PES fluoroscopic anatomy

Before beginning the swallowing study, it is necessary to analyze the pre-swallowing anatomy.

This includes assessing the location of the hyoid and thyroid cartilage, the size of the air column, and the cervical spine.

Fig 5: Evaluation of pre-swallow PES fluoroscopic anatomy

 1.2.- Laryngohyoid elevation

 Anterior-Superior Laryngohyoid Elevation Moves the larynx forward beneath the base of the tongue and directs the bolus posteriorly towards the hypopharynx.

The PES Opening requires both muscular relaxation of the cricopharyngeal muscle (CPM) and laryngohyoid elevation

CPM relaxation without elevation will not result in PES opening

Fig 6: Laryngohyoid elevation

 1.3.- Pharyngeal contractility

Assessing the pharynx's contractility is challenging, even for experienced physicians, and there is significant variability between different observers.

It's important to evaluate the pharyngeal area at rest and compare it to the image of maximum contraction.

Patients with a dilated pharyngeal area have more difficulty propelling the bolus through the UES and may be at risk for airway aspiration.

Fig 7: Pharyngeal contractility

1.4.- PES opening

The PES opening is determined by the size and weight of the bolus.

It relies on the contractions of the pharynx and tongue to propel the bolus through the primed PES into the esophagus.

Inadequate contractions of the tongue and pharynx result in insufficient pressure to open the PES, making it impossible to accurately evaluate the PES when these contractions are weak.

Fig 8: PES opening

1.5.- Evaluation of the posterior cricoid region

 Evaluation of this region is crucial in diagnosing swallowing dysfunction.

An evaluation of the posterior cricoid (PC) region on fluoroscopy is essential in the assessment of PES function.

Requires a large bolus of barium to distend the area for proper visualization

Fig 9: Evaluation of the posterior cricoid region

Fig 10: Common PC Findings

1.6.- Posterior hypopharyngeal wall

Is defined as the area on the posterior hypopharyngeal wall at the most cranial region of the esophageal inlet.

Fig 11: Posterior hypopharyngeal wall

1.7.- Airway Protection: The Role of the Pharyngoesophageal Area

The laryngopharynx serves both breathing and swallowing functions.

Three Levels of Defense Mechanisms for Airway Protection:

• Laryngeal Elevation and Epiglottic Inversion (PES)
• Closure of False Vocal Cords
• Closure of True Vocal Cords

Any Dysfunction in these layers of protection can lead to laryngeal penetration or aspiration.

Fig 12: Airway Protection: The Role of the Pharyngoesophageal Area

Cricopharyngeal bar or prominent cricopharyngeus muscle

Also referred to as a cricopharyngeal bar, cricopharyngeal achalasia, or cricopharyngeal hypertrophy.

The cricopharyngeal bar is a smooth, posterior bar- or band-like protrusion into the lumen and the barium column, seen on the lateral view, at the junction of the hypopharynx and cervical esophagus (level of C5-C6)

Cricopharyngeal bar may be seen in 5–10% of asymptomatic patients.

Fig 13: Cricopharyngeal bar or prominent cricopharyngeus muscle

1.8.- The esophageal function

Esophageal conditions such as hiatal hernia, esophageal dysmotility, reflux, and strictures are often more frequent in patients with CPM dysfunction and Zenker’s Diverticulum.

Fig 14: The esophageal function

1.8.1Cervical esophageal diverticula

Fig 15: Cervical esophageal diverticula

• Zencker´s diverticulum

This is the most common type of cervical esophageal diverticulum. Mucosal outpouching of the hypopharyngeal wall located in Killian's triangle between the upper fibers of the cricopharyngeus and inferior pharyngeal constrictor muscles.

Fig 16: Zencker´s diverticulum

• Other upper esophagus Diverticula:
• Killian-Jamieson diverticulum.- It is Less common than Zenker's. It is a pulsion diverticulum, protruding through a lateral anatomic weak site of the cervical esophagus below the cricopharyngeus muscle.
• Laimer's diverticulum.- located below the cricopharyngeal muscle, is a much rarer type. In VFSS they are indistinguishable from Zenker's Diverticulum.

Fig 17: illian-Jamieson diverticulum and Laimer's diverticulum

 1.8.2 Cervical esophageal osteophytes

Cervical osteophytes, though usually asymptomatic, can sometimes enlarge and cause swallowing difficulties.

Diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) are two common causes of pathological anterior cervical osteophytes.

Fig 18: Cervical esophageal osteophytes

 1.8.3 Other Structural causes of Oro-pharyngeal Dysphagia

Many causes of oropharyngeal dysphagia are functional (neurological, neurodegenerative diseases). However, there are also structural causes of oropharyngeal dysphagia.

Fig 19: Other Structural causes of Oro-pharyngeal Dysphagia

2.- Quantitative assessment

 Experienced clinicians' subjective assessment is unreliable in accurately determining critical parameters of the videofluoroscopic swallow study (VFSS), such as PES opening, laryngeal elevation, pharyngeal area, and transit times. Intra- and inter-rater agreement can be as low as 70%, making objective measurements essential for distinguishing normal from disordered swallowing, tracking changes over time, and providing precise research outcomes

Fig 20: Quantitative assessment of the pharyngoesophageal segment (PES)

2.1.- The pharyngeal area at rest

The pharyngeal area at rest is defined by two key lines:

A line drawn from the posterior nasal spine to the posterior pharyngeal wall at the level of the tubercle of the atlas.

A second line from the arytenoid to the epiglottis.

Enlarged pharyngeal area: Can indicate a weak pharynx and poor constriction. It is a significant risk factor for aspiration, which may affect swallowing safety.

Fig 21: The pharyngeal area at rest and The pharyngeal constriction ratio (PCR)

2.2.- The pharyngeal constriction ratio (PCR)

It is calculated by dividing the lateral pharyngeal area during maximal contraction by the area with a one cc bolus in the oral cavity.

Normal Values: A normal PCR approaches zero, indicating effective pharyngeal contractility.

As PCR increases, pharyngeal contractility diminishes.

Individuals with a PCR greater than 0.25 have a threefold increased risk of aspiration.

Fig 21: The pharyngeal area at rest and The pharyngeal constriction ratio (PCR)

2.3.- UES/PES opening diameter

Lateral View: Narrowest point of opening between C3 and C6

Anterior-Posterior View: Narrowest point between the pharynx and esophagus

Fig 22: UES/PES opening diameter

2. 4.- Laryngeal elevation

Fig 23: Laryngeal elevation

2.5.- PES opening duration

PES opening duration is measured from the time the head of the bolus enters the PES until the PES closes on the bolus.

Shortened PES opening duration may also increase aspiration risk and be targeted with therapy.

Fig 24: PES opening duration

2.6.- Airway closure duration

Airway closure duration is measured from the moment the arytenoid cartilage approaches the petiole of the epiglottis until the epiglottis returns to its resting position after swallowing

A reduced airway closure duration can increase the risk of aspiration.

Fig 25: Airway closure duration

 2.7.- Measurement of the cricopharyngeus bar to distinguish between obstructive and non-obstructive bars

Fig 26: Measurement of the cricopharyngeus bar to distinguish between obstructive and non-obstructive bars

 2.8.- Bolus Residue: Alteration of effectiveness.

Fig 27: Bolus Residue: Alteration of effectiveness.

 2.9.- Bolus Residue: Residue scales

There are multiple scales to assess pharyngeal residue and they are divided into two types.

• Observational
• Quantitative (pixels)

Fig 28: Bolus Residue: Residue scales

2.10.- Laryngeal penetration and/or aspiration: Loss of security

An alteration in the functioning of the Pharyngoesophageal Segment (PES), such as decreased pharyngeal clearance or inadequate opening of the Upper Esophageal Sphincter (UES), can lead to aspiration or penetration postdeglutory, resulting in a loss of safety. The degree of aspiration/penetration is measured using the Penetration-Aspiration Scale (PAS).

Fig 29: Laryngeal penetration and/or aspiration: Loss of security

Fig 30: Penetration-Aspiration Scale (PAS)