Zenker's diverticulum

Abstract

There is now strong evidence that acquired Zenker's diverticulum arises in most cases secondary to a poorly compliant, but normally relaxing, UES which cannot fully distend during the process of sphincter opening. This gives rise to increased hypopharyngeal intrabolus pressure during the phase of trans-sphincteric bolus flow; pressure which is imparted to the area of relative muscular weakness (Killian's dehiscence) just proximal to the cricopharyngeus. This combination of factors gives rise to posterior herniation of the pouch over many years. The restricted opening of the cricopharyngeus is a result of muscle fibre degeneration and fibroadipose tissue replacement. For this reason, cricopharyngeal myotomy is the essential component for successful surgical treatment of the condition. The precise aetiology of this myopathic process affecting the cricopharyngeus is unknown and may be multifactorial. However, an underlying myositis with a predilection for the cricopharyngeus muscle is likely to be one such factor in some cases.