This is protrusion of the mucosa through the Killian's dehiscence, a weak area of the posterior pharyngeal wall between the oblique fibres of thyropharyngeus and the transverse fibres of the cricopharyngeus at the lower end of the inferior constrictor muscle. These fibres along with the upper circular fibres of the oesophageous form a physiological sphincter of upper oesophagus. It has been seen that is these patients there is incomplete relaxation of the sphincter during swallowing, early cricopharygeal contraction and abnormalities of the pharyngeal contraction waves.

Clinical features : This condition is more commonly seen in elderly population and the female to male ratio is 2:1.
In the early phase when the diverticulum is small, patients may complain of feeling of something in the throat or slight regurgitation on swallowing. As the diverticulum enlarges regurgitation symptom becomes more severe. They start complaining that they bring up undigested food material hours after meal especially on bending down or turning over in bed at night. They may even wake up in the night as a result of tightness in the throat and fit of cough. Occasionally they may present with recurrent chest infection as a result of aspiration of liquid brought up from the pouch. Further enlargement of the pouch will cause a gurgling noises in the neck with swallowing and the patients may present with a swelling in the neck. The swelling is usually on the left side of the neck because as the pouch enlarges the resistance of the vertebral column behind cause it to turn laterally to the left.

Radiological examination :

Barium swallow- a thin emulsion of barium is given to the patient to swallow. This will delineate the pouch and the upper oesophageous.
Videofluoroscopic swallowing study- this gives the additional information about the pharyngeal contraction waves and the performance of the upper oesophageal sphincter.

Treatment : Surgery in indicated when the pouch is associated with progressive symptoms or the abnormalities of the upper oesophageal sphincter mechanism is causing considerable dysphagia.

If the size of the diverticulum is 2-4 cm it can be suspended upside down after performing the cricopharyngeal myotomy.
If the size is more than 4 cm, it is best removed after performing cricopharyngeal myotomy.

Operative procedure :

The patient is placed in supine position with a small pillow under the shoulders. The head is supported on a doughnut type pillow and is hyperextended and turned to the right.
An incision is made along the anteromedial border of the left sternomastoid muscle from a few cm below the ear lobule to a point just above the sternal notch. The subcutaneous tissue and the platysma is divided. The sternomastoid muscle is freed by sharp dissection from the underlying vascular structure. The omohyoid muscle and the prethyroid muscles are separated or cut to expose the jugular vein, carotid artery and the thyroid gland. The middle thyroid vein is divided and if necessary, the inferior thyroid artery is found and divided as laterally as possible to protect the recurrent laryngeal nerve. These will help to retract the thyroid gland medially. Now the recurrent laryngeal nerve is identified in the groove between the trachea and the oesophagus and safeguarded. Thereafter the pharynx and the oesophageous is dissected free from the prevertebral fascia. A 36-Fr bougie is passed into the oesophageous for use as a stent. Myotomy is begun on the oesophageous and proceeds proximally. The mucosa is recognized by its slightly bluer colour compared with the muscle and by the submucosal plexus of the vessels that overlies it. To make sure that the myotomy is complete the mucosal bulge through the myotomy should be in continuity with the mucosa of the sac. Now the diverticulum is grasped with a atraumatic forceps and the facial condensation around it are dissected away. This is done till the neck is defined. Then the diverticulum is divided and sutured transversely. This can be also done by the help of the stapler. The muscle around it may or may not be sutured. However if the diverticulum is around 2-4 cm, it can be suspended by suturing it to the retropharyngeal fascia or to the anterior spinal ligament. This will allow the body and fundus to empty continuously into the oesophageous.

Endoscopic stapling technique : A specialised stable gun is available which can be passed down a pharyngoscope. This can divide the anterior wall of the pouch and the posterior wall of the oesophageous and hence a complete myotomy is done. The staple provides an instant two layer closure at the division. This will allow any food or fluid to drain into the oesophageous. This technique is associated with low morbidity and therefore very useful for the elderly.

Postoperative : The patient is feed through nasogastric tube for 3-6 days. Gastrograffin swallow is repeated on 7th postoperative day. If there is no leak oral feeding is started.