Pharyngeal Pouch

A pharyngeal pouch represents a posteromedial pulsion diverticulum through Killian's dehiscence. It is a herniation between thyropharyngeus and cricopharyngeus muscles that are both part of the inferior constrictor of the pharynx.
The aetiology is unknown¹ but malfunction of the upper oesophageal sphincter probably contributes. A diagrammatic representation of the anatomy can be found in the Surgical Tutor reference.²

It is uncommon but the incidence appears to be higher in the UK than elsewhere.³ It is largely confined to those over 70 years of age and males outnumber females by 5:1.

The usual presenting features are dysphagia, regurgitation, aspiration, chronic cough and weight loss.⁴
Usually there are no clinical signs but there may be a lump in the neck that gurgles on palpation. There may also be halitosis from food decaying in the pouch.

Usually this is the differential diagnosis of dysphagia and must include oesophageal carcinoma and oesophageal strictures, rings and webs.

Endoscopy should be avoided as an initial investigation for fear of perforating the lesion. A barium swallow may show a residual pool of contrast within the pouch.
Indirect laryngoscopy may show a pooling of saliva within the pyriform fossa.

This is dependent upon the size of the pouch. With recognition of the importance of the cricopharyngeus muscle in the pathogenesis of the pouch, the emphasis on treatment has shifted from diverticulectomy to cricopharyngeal myotomy. Minimally invasive techniques have become established with endoscopic stapling devices.⁵

Diverticulectomy

This is used for larger lesions. A rigid endoscope is passed and the pouch is packed with gauze. An incision is made at the level of the cricoid cartilage and the fascia at the anterior border of sternomastoid is divided. The pouch is identified and excised and the defect closed. Cricopharyngeal myotomy is performed to prevent recurrence. The patient is fed via a nasogastric tube for a week postoperatively.
Potential complications include:

• Recurrent laryngeal nerve palsy
• Cervical emphysema
• Mediastinitis
• Cutaneous fistula.

Dohlman's procedure⁶

This is suitable for smaller lesions and is performed via an endoscope. A double-lipped oesophagoscope is used and the wall between the diverticulum and oesophageal wall is exposed. The hypopharyngeal bar is divided with diathermy or laser.
The advantages are that it is a minimally invasive techniques that allows:⁷

• Shorter duration of anaesthesia
• More rapid resumption of oral intake
• Shorter hospital stay
• Quicker recovery.

There is no evidence from high quality randomised controlled trials to demonstrate the effectiveness of endoscopic compared with open procedures for pharyngeal pouch. There is no good evidence to establish whether one endoscopic procedure is superior to another.⁸ There is some evidence that whilst endoscopic surgery is safer for the elderly and frail that there may be a higher rate of recurrence and the conversion to an open procedure may be required if there are technical difficulties or perforation during operation.⁹

• Aspiration from the pouch can cause inhalation pneumonia.
• Carcinoma may develop in the pouch although the true level of risk is debated.^3,4

Friedrich Albert von Zenker was a German physician and pathologist. He was born in Dresden in 1825 and died in 1898. He studied at Leipzig and received his doctorate in 1851. His name is also attached to Zenker's degeneration that is severe glassy or waxy hyaline degeneration or necrosis of skeletal muscles in acute infectious diseases and Zenker's paralysis that is peroneal nerve palsy.