PHARYNGEAL POUCH (Zenker's Diverticulum)


DEFINITION

Essentials of diagnosis: dysphagia, regurgitation, gurgling, halitosis.
Pouches can form in different parts of the oesophagus; Zenker's is at the cervical oesophagus.

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INCIDENCE

Rare.
M>F.
Mainly >60yrs.
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AETIOLOGY

Acquired, degenerative.

Pathogenesis
A triangular area of weakness (Killian triangle) exists in the posterior wall, limited inferiorly by cricopharyngeus, and superiorly by the inferior pharyngeal constrictor.
- see Netter plate 222; "zone of sparse muscle fibres"

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BIOLOGICAL BEHAVIOUR

Natural History

Lack of coordination between the pharyngeal contraction at opening of UES, or a hypertensive UES.
--> pressure --> pulsion herniation (progressive) of mucosa and submucosa through Killian triangle.
- note that they are not the entire wall of oesophagus, so are considered 'false diverticula'
- tends to deviate from the midline, mostly Left.
Progressive food stasis and dysphagia.

Other
Another sort of diverticulum can form low in the oesophagus (epiphrenic diverticulum)
- pulsion or traction.
--> associated with other oesophageal motility disorders; may need resection, long myotomy and partial fundoplication.

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MANIFESTATIONS

Symptoms often initially relate to the motility problem
- later progress to those of the pouch itself.
Dysphagia
--> difficulty initiating swallowing.
Later, regurgitation of old undigested food.
- bland and not bitter like acid
- stuff that never reached the stomach.
Halitosis
Cough and aspiration of debris
Gurgling sounds in neck
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INVESTIGATIONS

Imaging
Barium swallow = best; video swally esophagogram.
- shows position and size.
- as well as bolus transport by esophagus.
- or prominent cricopharyngeal bar at least.
- can rule out hiatal hernia or other problem.

Endoscopy
Often found incidentally.
Can be dangerous as risk of perforating the pouch.

Manometry
Not necessary as a routine.
May need to be placed with endoscopic guidance or might coil in the divertic.
Lack of coordination between pharynx and cricopharyngeus
- hard to capture rapid skeletal muscle events on manometry.
Often hypertensive UES
Possibly hypotensive LES and abnormal peristalsis.

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MANAGEMENT

Mostly found incidentally -> leave alone.
Surgery is the only effective therapy for symptomatic patients.
- should be considered regardless of old age.

Surgical
Excise diverticulum
Myotomy of cricopharyngeus and upper 3cm of posterior oesphageal wall.
- myotomy alone if <2cm in size.
--> then excision or suspension of the diverticulum.
Failure to divide the dysfunctional cricopharyngeus leads to a high rate of recurrence and increased risk of leak.
Treat GERD first, or can lead to aspiration when UES treated.

See: Zenker Diverticulum Repair

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