Dr John Chaplin – Auckland Head and Neck Specialist

Pharyngeal Pouch (Zenker’s Diverticulum)

 

Anatomy

A pharyngeal pouch or Zenkers Diverticulum is an outpouching of the pharynx at the level of the larynx (voice Box). Pouches occur in older people and are the result of fibrosis of a band of muscle at the top of the oesophagus callled cricopharyngeus. This muscle usually relaxes during swallowing but because of the fibrosis it remains tight and the pressure created with the swallow causes the lining of the throat above to bulge out through a weaker area of muscle above cricopharyngeus called Killians Dehiscence.

 

Presentation

Patients are older and usually male. Symptoms include difficulty swallowing (dysphagia) with food sticking at the level of the larynx, regurgitation of undigested food after finishing eating and particulary when lying down at night. Other symptoms can be gurgling noises when swallowing, a soft mass in the left neck, recurrent cough or repeated aspiration pneumonia. There is a small risk that cancer can develop in a pouch that has been present for a long time and if this occurs symptoms can include: pain, voice change and airway obstruction.

Investigation

The definitive test for this condition when suspected clinically is a barium swallow (). The barium will outline the pouch and will also show the indentation that the scarred cricopharyngeus muscle causes. Chest X Ray or CT scan can also be important in patients with recurrent cough or aspiration symptoms. Aspiration pneumonia can result from repeated aspiration of pouch contents into the airway.

 

Treatment

Surgery is the only treatment for pharyngeal pouch. There are a variety of surgical approaches split into two main groups: endoscopic and external approaches.

Endoscopic Approach

This approach is performed through the throat using a special endoscope that passes partly into the oesophagus and partly into the pouch. The common party wall, that contains the scarred muscle fibres of cricopharyngeus, is then divided using a variety of cutting instruments. These include: Endoscopic stapling devices, CO2 laser, diathermy and scalpel or scissors. The pouch itself is not removed but dividng the wall converts the pouch into part of the pharynx/ oesophagus and food and debris cannot be retained but pass into the oesophagus.

Advantages:
May be quicker procedure
No external incision

Disadvantages:
Access can be difficult- cannot do some cases endoscopically
Recurrence of pouch more common
Higher complication rates.

External Approach

Intially the pouch is packed endoscopically to make identification in the neck easier. A tube is passed into the oeosphagus to help identification and retention of the diameter of the oesophagus. An incision is made in the left neck, either horizontally at the level of the cricoid cartilage or diagonally along the anterior border of the sternomastoid muscle. The pouch is identified and muscle layers are stripped off the surface of it. Depending mainly on the size of the pouch it is then either excised, suspended or inverted. Larger pouches are better managed by excision. If excised the procedure is best performed using a stapling device that automatically staples the pharynx closed and excises the pouch at the same time. The fibres of the cricopharyngeus muscle are always divided completely and sometimes excised to prevent recurrence of the pouch. The wound is then closed over a drain.

Advantages
All pouches can be treated this way
lower complication rates
Minimal risk of recurrence

Disadvantages
Can be a longer procedure
Need for external incision

Complications

It is imporatnt to remember that these complicatons are rare when being treated by an experienced head and neck surgeon.

Recurrent laryngeal nerve palsy
This nerve passes near the pouch and can be injured during the surgery. Injury can result in a hoarse and breathy voice. The nerve cannot be seen in an endoscopic approach and is not usually identified even in an external approach. Injury is rare.

Salivary Fistula (Leak)
Saliva can leak from the repaired pharynx and can cause infection in the neck. This most commonly occurs with endoscopic approaches and can occur in and external approach where the pouch is excised. It is much less common if the pouch is stapled and excised.

Haematoma
Bleeding can occur in any neck operation and if a haematoma occurs it will need to be drained in the operating room.