Cricopharyngeal achalasia seems the commonest cause of oro-pharyngeal dysphagia in the elderly
W. Pelemans (Leuven)
Aspects of the normal physiology of the UES
The upper esophageal sphincter (UES) is a musculoskeletal valve composed of the cricopharyngeus muscle, the lower part of the inferior pharyngeal constrictor, and the cricoid cartilage, to which these muscles attach. The UES regulates the passage of material between the pharynx and the esophagus: it keeps air from entering the esophagus, allows swallowed material to pass into the esophagus and prevents the regurgitation of esophageal contents into the pharynx.
This contribution will examine the swallow-induced opening of the UES. This opening of the sphincter is only one component of the complex motor events which take place during the pharyngeal stage of a normal deglutition.
The opening of the UES is realized by a double action : an abrupt fall in the resting tone of the UES muscles and anterior elevation of the larynx. The sudden disappearance of the tonic muscular contraction in the pharyngo-esophageal region creates the possibility for opening of the sphincter by the pull of the larynx.
In this way, anterior elevation of the larynx and cricopharyngeal opening are intimately related .
Asherson [ 1 ] was the first to consider the possibility that defective opening of the UES might cause swallowing problems. He describes in his study several patients with a characteristic profile radiograph of the pharynx (figure 1): a hold-up of the barium bolus above the cricopharyngeus, swallowed boli which piled up in the hypopharynx forming a reservoir which acts as a « drip feed » to the esophagus. Asherson introduced the term achalasia of the cricopharyngeus to describe this functional disturbance. He suggested that there was partial or complete failure, as well as a delay in the relaxation of the cricopharyngeal sphincter in these patients. However, Asherson gave no clear radiological description of the cricopharyngeus muscle itself.
Figure 1. The typical radiological appearance of achalasia of the UES in a patient with dermatomyositis.
Later studies have made clear that the description and the patients of Asherson were extreme cases and that other radiological signs exist which suggest a failure of relaxation in the cricopharyngeal region. However, the term « cricopharyngeal achalasia » often used to designate this insufficient relaxation of the cricopharyngeal muscle during swallowing seems inappropriate, since achalasia means «not relaxing» and in many patients the muscle does relax, even if delayed or incomplete .
The cricopharyngeus is not discernible on a normal radiography; the fully distented pharynx has a smooth posterior wall when the UES opens in a normal way. In some patients however, it can be visualized. The roentgenographic manifestations of the cricopharyngeus range from a minimal indentation in the posterior wall of the pharynx at the C5- C6 level to a horizontal shelf that completely occludes the lumen . The radiological picture of the cricopharyngeus can be a constant and continuous phenomenon! in some patients; in others the indentation
seems to be transient [4, 3]. The cricopharyngeus can appear at different stages in the pharyngeal phase. The posterior impression can be present only at the beginning or the end of the barium passage, in other patients it is manifest throughout the passage of the bolus.
It is important to note that the cineradiography of patients with a demonstrable cricopharyngeus often reveals other associated pharyngeal abnormalities.
The prevalence of a visible cricopharyngeal muscle is 5-10 p. cent in routine cine or video study series [8, 4, 3]. In most patients this abnormality does not induce swallowing problems. In the study of Curtis et al.  dysphagia was found in less than 15 p. cent of the patients with a visible cricopharyngeus. In patients with oropharyngeal dysphagia studied by cineradiography, 22 p. cent had dysfunction of the cricopharyngeal muscle . Although the incidence of cricopharyngeal dysfunction increases with advancing age, it is not unknown in infants and it has also been described as a congenital lesion.
A failure of cricopharyngeal relaxation can exist as an isolated, idiopathic entity. However, in many cases the disturbance in opening of this sphincter is associated with other pathological conditions. It has been described in cerebrovascular diseases, after laryngectomy, in bulbar poliomyelitis and syringobulbia, in oculopharyngeal muscular dystrophy, thyroid myopathy and dermatomyositis, in recurrent laryngeal nerve paralysis, Parkinson's syndrome, unilateral cervical vagotomy...
The reason for the lack of complete relaxation of the cricopharyngeus is not fully understood. The radiographic appearances are consistent with many hypotheses . Moreover, the variability in the appearance of the cricopharyngeus and the variety of associated conditions makes an uniform physiopathological explanation very unlikely.
Cricopharyngeal achalasia in the elderly
Some evidence suggests that minor changes occur in the function of the LIES in normal elderly people. The resting tone diminishes with age and manometric observations indicate that the UES more easily forgets to relax in asymptomatic persons . A minor degree of cricopharyngeal « achalasia » is also found more frequently in radiological studies of elderly subjects .
In daily practice, the majority of deglutition disorders in elderly people occur in the course of cerebrovascular disease. These patients exhibit a variety of physiologic disturbances in swallowing, usually occurring in combination rather than as isolated disorders. One of these disturbances can be a failure of relaxation of the cricopharyngeus. However, in the videofluorographic study of Veis and Logemann only 5 p. cent of the patients with swallowing problems caused by a cerebro-vascular accident experienced cricopharyngeal dysfunction. Cricopharyngeal achalasia is not a prominent cause of swallowing problems in the elderly as an isolated disorder; a disturbed opening of the cricopharyngeus can be found combined with other functional disturbances of the deglutition act.
As far as this cricopharyngeus dysfunction is the most important trouble, cricopharyngeal myotomy can be warranted in some well selected patients .