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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