Diverticula of
Esophagus
Diverticula may form at any point along the length of the esophagus. The
pathogenesis of the diverticula is usually either pulsion (due to high
intrinsic esophageal pressure secondary to a motility disorder) or traction secondary
to a process extrinsic to but neighboring the esophagus that tethers to and
pulls the esophageal wall away from the lumen.
In the proximal esophagus, a pulsion
Zenker diverticulum may form. This outpouching occurs in a mechanistically
weak area of the pharynx located posteriorly between the inferior pharyngeal
constrictor and the cricopharyngeus muscles (triangle of Killian). The source
of pulsion forces is felt to be contraction of the pharynx against a fibrotic,
poorly compliant cricopharyngeus. Treatment is myotomy of the cricopharyngeus
to prevent reformation with diverticulectomy, diverticulopexy, or division,
depending on the size of the diverticulum. In the midesophagus, traction
diverticula are more common. These typically occur from external tethering
forces, such as mediastinal adenopathy involved with cancer or with
granulomatous infection, such as tuberculosis or histoplasmosis. The openings
of the outpouchings tend to be broader, without acute entry into the esophagus
when compared with the pulsion type. Nonspecific diverticula, possibly due to
pulsion, may also form in the midesophagus, often incidentally and
sometimes causing symptoms. The precise etiology is unclear.
A distal esophageal epiphrenic
diverticulum is typically caused by pulsion and forms proximal to the gastroesophageal
junction. It generally results from a hypertensive lower esophageal sphincter
with or without changes of achalasia. Similar to treatment of a Zenker
diverticulum, a myotomy of the highpressure zone must be performed, in
addition to diverticulectomy for large sacs.
