Esophageal webs & rings
- Esophageal web:
A thin mucosal fold that protrudes into the lumen and is covered with squamous epithelium. Webs most commonly occur anteriorly in the cervical esophagus, causing focal narrowing in the post-cricoid area.
- Esophageal rings: 2 types
- Mucosal Schatzki rings (B rings):
Mucosal structures at the gastro-esophageal junction that are smooth, thin, and covered with squamous mucosa above and columnar epithelium below. This is the common type.
- Muscular rings (A rings):
This type is rare, usually seen in children, located within 2 cm of the squamo-columnar junction, and characterized by hypertrophic musculature in the esophageal body.
The caliber of a muscular ring changes during peristalsis, distinguishing it from a peptic stricture or mucosal ring.
Pathogenesis of mucosal rings is controversial.
It may be due to either:
- Chronic damage from GERD.
- Congenital or developmental.
Pathogenesis of cervical webs is also controversial. It may be congenital or acquired as an extra-cutaneous manifestation of systemic disorders such as Epidermolysis bullosa, Bullous pemphigoid & Pemphigus vulgaris.
Esophageal rings and webs cause dysphagia to solids..
Detection is done by fluoroscopy using the full-column technique. This technique will detect 100% of esophageal rings.
Endoscopy is less sensitive in detecting esophageal rings and strictures since they will not be seen unless the lower esophagus is widely distended. Endoscopically, esophageal ring appears as a thin membrane with a concentric smooth contour that projects into the lumen.
Asymptomatic Schatzki rings are found in 6-12% of routine barium studies and in 15-25% of cases of esophageal dysphagia.
An association between mucosal rings & eosinophilic esophagitis has been reported.
Although webs have classically been associated with iron-deficiency (Plummer-Vinson syndrome), at least one epidemiologic study found no correlation between cervical webs and iron deficiency.
- They are usually ruptured during diagnostic endoscopy.
- Esophageal dilation may be necessary.
- Rarely, they are refractory to standard dilations. These are treated by endoscopic laser division.
- First line of treatment is dilation with a large bougie (≥50 French).
- Dilation can also be done with a balloon dilator that corresponds in size to a large bougie (18 to 20 mm).
- When rings are dilated, the initial dilator used is large and reflects the goal of ring disruption.
- A possible alternative to dilation with a large bougie is disruption of the ring with a biopsy forceps or with electrosurgical incision.
- Patients with multiple esophageal rings are an exception. Forceful dilation with a large caliber bougie has been associated with deep mucosal tears and esophageal perforation. Such patients should be dilated very cautiously.
- Prospective studies suggest that symptom recurrence after dilation is probably the rule rather than the exception and should be anticipated after one year. Recurrence also develops following other methods to disrupt the ring.
- Acid suppression may reduce the risk of recurrence as illustrated in a controlled trial, so it is recommended after dilatation to give long term PPIs.
- Balloon dilation, steroid injection, surgery, and endoscopic incision, have been proposed to the small number of patients with lower esophageal rings that fail to respond to repeated bougie dilatation.