Achalasia is a motility disorder of the oesophagus characterized by failure of the lower oesophageal sphincter to relax in response to swallowing and absence of peristalsis in the oesophageal body. The disease is most often progressive, leading to gradual dilatation of the oesophagus above the sphincter. Patients typically present with dysphagia, regurgitation, and substernal chest pain. Surgical or pneumatic disruption of the lower oesophageal sphincter relieves the obstruction and effectively restores swallowing.

The earliest available description of the disease and a successful treatment was provided in 1674 by Thomas Willis who treated a man with perpetual vomiting. Willis fashioned a sponged-tipped rod made of whale bone that the patient used to force open his cardia after meals for the following 15 years. Russell first reported treatment of the constricted sphincter by inflation of a silk-covered rubber balloon in 1887. Von Mikulicz introduced the term cardiospasm in 1904 and described dilatation of the gastro-oesophageal junction through a gastrostomy. In 1913 Heller performed surgical division of the muscular narrowing by means of two myotomies on the anterior and posterior surface of the lower oesophagus, through an abdominal incision. Plummer developed a successful method of forcefully dilating the sphincter with hydrostatic pressure using a rubber bag passed over a thread; he reported his personal experience with 301 cases in 1921. Modifications of the procedures introduced by Heller and Plummer are the mainstay of effective therapy today.

The incidence rate of radiologically confirmed cases of achalasia in population studies from Great Britain and the United States averages between 0.4 and 0.6 cases/10&sup5; population/year, although peak rates as high as 2 cases/10&sup5; have been observed. The disease is known in most races and on all continents. In Europe and the United States, men and women are affected in equal proportions, although some series show a slight male predominance. Most patients present between the third and fifth decade of life, and less than 5 per cent of patients have the infantile type of disease. In South America, particularly in Brazil, mega-oesophagus is most frequently a manifestation of Chagas' disease, caused by Trypanosoma cruzi infection. Chagas' disease resembles achalasia because of the diffuse ganglion cell involvement and similar abnormalities of oesophageal motility. Patients with Chagas' disease, however, develop disease of multiple organs, including cardiomyopathy, megacolon, and megaureter. It can be diagnosed by specific serological tests.

The primary abnormality causing chronic constriction of the lower oesophageal sphincter and loss of peristalsis remains unknown. Potential aetiologies are a primary disease of the oesophageal wall, a disorder affecting the peripheral or central autonomic motor neurones, and autoimmune or inflammatory disease. Various experimental procedures, including selective ischaemic or toxic injury to the oesophagus and bilateral cervical vagotomy, result in conditions similar, but not identical, to achalasia.

The earliest documented histological finding in achalasia is degeneration of ganglion cells in the myenteric plexus of Auerbach. A reduction in number or absence of ganglion cells, predominantly in the oesophageal body but also in the distal narrowed oesophageal segment is noted. These changes are generally more pronounced in advanced disease. Recent studies have found a selective impairment of postganglionic inhibitory neurones in the circular layer of the lower oesophageal sphincter. As a result, cholinergic agonists produce an accentuated tightening and the lower oesophageal sphincter relaxant cholecystokinin produces a paradoxical contraction of the sphincter. Neural damage occurs at two further levels. Abnormalities similar to Wallerian degeneration occur in both myelinated and non-myelinated fibres of the vagus nerve. Nerve cells in the dorsal motor nucleus of the vagus nerve in the brain-stem are diminished in number or absent.

Ultrastructural studies of oesophageal muscle fail to demonstrate a specific injury in achalasia. In advanced disease, gross observation of the oesophagus demonstrates a 1.5 to 4.5 cm distal narrowing with normal wall thickness. The wall of the oesophageal body is thickened due to an increase of the circular muscle layer. The lumen is enlarged, elongated, and tortuous. Diverticula or pseudodiverticula of the mid-oesophagus occur occasionally. The mucosa demonstrates typical lesions of chronic stasis, including oesophagitis and ulcerations.

A gradual onset of symptoms over months to years is characteristic of achalasia. Over 90 per cent of all patients have symptoms for longer than 1 year, and half are symptomatic for more than 3 years. Some may have symptoms for several decades. In addition to obstruction of swallowing, patients complain of regurgitation or vomiting of undigested food. Ellis and Olsen described how a typical patient copes with his eating problem.

He shuns company while eating and is unwilling to dine in public. He learns quickly which foods will pass most easily and hence often avoids cold foods or solids such as meats or apples. He knows that he must not eat before retiring for fear of regurgitation, choking, and coughing. Some patients with advanced achalasia develop techniques for forcing food through the cardia. Merely drinking large quantities of water will sometimes overcome the resistance at the cardia [ . . . ]. Others learn to execute a “Valsalva maneuver”, [ . . . ] thus increasing intrathoracic pressure until the lower sphincter gives way. In the process the patient usually stands in a crouched position, often holding on to a mantelpiece or stair rail.

Weight loss is present in 60 per cent of patients. Substernal chest or epigastric pain occurs in one-third of all patients. Nocturnal regurgitation may lead to aspiration, and pneumonia is present in 10 per cent of patients. In infants respiratory problems may be the first symptom to prompt evaluation and diagnosis.

Typical findings on plain chest radiograph include widening of the mediastinum and a posterior mediastinal air-fluid level. Chronic aspiration may cause abnormalities of the lung fields. Barium swallow demonstrates the characteristic dilatation of the oesophagus with a narrowing at the gastro-oesophageal junction (bird's beak deformity) in over 85 per cent of patients (Fig. 1) 913,914. The size of the oesophageal body on contrast studies provides an approximation of disease severity: a diameter of less than 4 cm is termed mild disease, 4 to 6 cm moderate, and greater than 6 cm severe (‘mega-oesophagus’). Further indicators of disease severity are the amount of retained food and degree of peristalsis observed on fluoroscopy.

Oesophageal manometry confirms the clinical diagnosis and reliably separates patients with similar symptoms due to other motility disorders, such as diffuse oesophageal spasm (Fig. 2) 915. Four criteria are characteristic of achalasia: elevated lower oesophageal sphincter pressure, incomplete or absent relaxation of the lower oesophageal sphincter, absence of peristalsis in the oesophageal body, and elevated intra-oesophageal pressure. Absence of co-ordinated peristalsis is required for diagnosis, but weak simultaneous contractions are often observed early in the course of the disease. A subgroup of patients have ‘vigorous achalasis’, a hyperdynamic disco-ordinate motility pattern with simultaneous, high amplitude contractions of the oesophageal body. The latter condition may be accompanied by epiphrenic diverticula.

Complete endoscopic examination of oesophagus and stomach should be part of the initial evaluation, to detect disease complications, such as ulceration, and to rule out carcinoma. The oesophagus is often patulous and contains food particles and secretions. The mucosa exposed to these contents is frequently inflamed. The lower sphincter is closed, but provides little or no resistance to the endoscope which is easily advanced into the stomach.

Two conditions mimic the radiological and manometric features of achalasia. Chagas' disease occurs uncommonly outside South America and generally also affects other organs. Pseudoachalasia is the rare presentation of a carcinoma at the gastro-oesophageal junction with gradually worsening dysphagia, narrowing at the lower sphincter, and manometric findings characteristic of achalasia. Patients typically have symptoms for less than 1 year, and weight loss predominates. Inhalation of amyl nitrate leads to sphincter relaxation in achalasia, but not in pseudoachalasia. The diagnosis of pseudoachalasia is made by endoscopic examination and biopsy, but findings are subtle and require a high index of suspicion and often, serial examination.

Diffuse oesophageal spasm may present with symptoms similar to those of early achalasia. Indignation of this condition are diffuse narrowing or segmental contractions of the oesophagus on radiological examination and motility studies demonstrating relaxation of the lower oesophageal sphincter in diffuse spasm. A peptic stricture that occurs as a complication of scleroderma may imitate achalasia on contrast studies, but concomitant systemic manifestations usually indicate the diagnosis.

Successful therapy consists of judicious weakening of the lower oesophageal sphincter by forceful dilatation or oesophagomyotomy to allow gravity drainage of food while avoiding chronic gastro-oesophageal reflux. Therapy does not restore the normal anatomy of the sphincter or co-ordinated peristalsis of the oesophageal body. Sphincteric disruption, however, relieves dysphagia and regurgitation in most patients. Therapy with calcium channel blockers and nitrates decreases lower oesophageal sphincter pressure transiently. Although patients with mild and moderate symptoms of achalasia experience improvement of swallowing, these drugs do not produce lasting relief and no information on disease progression during treatment is available. Drug therapy should therefore be used for extended periods only in patients unable to undergo standard treatment.

Forceful dilatation is accomplished with an expandable balloon made of silk-covered rubber or polyurethane, inflated with water or air, and advanced either over thread, an olive-tipped bougie, or under radiographic control. Pneumatic dilatation using a polyurethane balloon and fluoroscopy is the currently preferred method. The dilator is typically placed through the narrowed segment and the balloon is rapidly inflated for a period ranging from seconds to a few minutes. If the result is unsatisfactory repeated attempts or a larger balloon is required. The patient can leave the hospital on the same day or after overnight observation. If the first treatment produces no improvement, another dilatation may be considered after 3 months.

Approximately 70 per cent of patients improve after the procedure. Advantages of dilatation are the avoidance of general anaesthesia and the painful incision. Treatment cost are lower. Further dilatations are required in approximately 16 per cent of patients and a myotomy in 8 per cent. Disadvantages include a high incidence of gastro-oesophageal reflux disease (20 per cent of patients) and a 1 to 10 per cent risk of oesophageal perforation. Appropriate treatment of acute perforation consists of thoracotomy and primary repair of the oesophagus.

In principle, this is derived from the duplicate Heller myotomy by the abdominal approach. However, many modifications of oesophagomyotomy for achalasia have evolved with the aim of reducing the postoperative complications of reflux and recurrent obstruction.

When operating through the abdomen, division of the phreno-oesophageal ligament is required to expose the lower oesophagus. The added effects of a weakened sphincter and a dissected hiatus are followed by high incidence of reflux, making a routine fundoplication necessary. Thoracotomy offers direct access to the lower sphincter without obligatory injury to the diaphragmatic attachments and risk of reflux (Fig. 3) 916. In the future, laparoscopic or thoracoscopic approaches may reduce perioperative discomfort and hasten recovery, but effectiveness and safety of these procedures await confirmation.

The longitudinal incision into the muscle must divide all circular fibres on the lower oesophagus and reach proximally to all dilated oesophagus. Any remaining constriction will lead to persistent dysphagia. However, extending the incision too far on to the gastric wall results in free reflux. The myotomy should therefore continue for less than 1 cm on to the stomach, where the presence of transverse cardiac veins is first noted. Exact execution of this step is probably the most critical determinant of postoperative results.

While those who perform only myotomy restrict a fundoplication to specific indications, i.e. the presence of a hernia, others consider it routine. They argue that a widely dissected hiatus provides improved exposure and believe that the incidence of postoperative reflux is reduced. However, the rate of failure after fundoplication is 10 to 15 per cent, which equals the overall incidence of postoperative reflux after myotomy and raises doubt regarding the benefit of adding this procedure in all patients. If reconstruction of the hiatus is required, the lack of oesophageal peristalsis often results in recurrent obstructive symptoms which require oesophageal dilatation and long-term observation. Total fundoplication is therefore avoided, and ‘loose’ Belsey and ‘floppy’ or incomplete Nissen repairs are preferred.

Surgical myotomy results in improvement in 90 per cent of patients. In the Mayo Clinic experience, simple myotomy achieved good or excellent results in over 90 per cent of patients. Unsatisfactory long-term, results were noted in 6 per cent of myotomy patients, as compared to 19 per cent after forceful dilatation. Thus surgical therapy produces better results with risk of postoperative reflux disease.

Patients presenting with extensive dilatation of the oesophageal body or unrelenting post-treatment reflux may respond poorly to conventional therapy. Replacement of the oesophagus with stomach or intestinal interposition should be considered to alleviate symptoms.

Patients with achalasia have an increased risk of dying from cancer of the oesophagus. Successful palliation does not prevent malignancy, but cancer usually develops in patients who had advanced achalasia at the time of definitive therapy. Treatment during the early stage of the disease may thus afford a relative protection from oesophageal cancer. Most frequently located in the middle-third of the oesophagus, tumours develop in 5 to 8 per cent of patients, typically many years after diagnosis or treatment. Routine long-term endoscopic examination with brush cytology or biopsy is recommended and should continue indefinitely, even after effective palliation.

Aggestrup S, Holm JC, Sorensen HR. Does achalasia predispose to cancer of the esphagus? Chest, 1992; 102: 1013–16.

Belsey R. Functional disease of the esophagus. J Thoracic Cardiovasc Surg, 1966; 52: 164–88.

Csendes A, Braghetto I, Henriquez A, Cortes C. Late results of a prospective randomised study comparing forceful dilatation and oesophagomyotomy in patients with achalasia. Gut, 1989; 30: 299–304.

Ellis FH, Olsen AM. Achalasia of the Esophagus. Philadelphia: WB. Saunders, 1969.

Ellis FH, Crozier RE, Watkins E. Operation for esophageal achalasia. Results of esophagomyotomy without an antireflux operation. J Thoracic Cardiovasc Surg, 1984; 88: 344–51.

Ferguson MK. Achalasia: current evaluation and therapy. Ann Thoracic Surg, 1991; 52: 336–42.

Ferguson TB, Burford TH. An evaluation of the modified Heller operation in the treatment of achalasia of the esophagus. Ann Surg, 1960; 152: 1–9.

Kahrilas PJ, Kishk SM, Helm JF, Dodds WJ, Harig JM, Hogan WJ. Comparison of pseudoachalasia and achalasia. Am J Med, 1987; 82: 439–46.

Little AG, Soriano A, Ferguson MK, Winans CS, Skinner DB. Surgical treatment of achalasia: results esophagomyotomy and Belsey repair. Ann Thoracic Surg, 1988; 45: 489–94.

Okike N, Payne WS, Neufeld DM, Bernatz PE, Pairolero PC, Sanderson DR. Esophagomyotomy versus forceful dilation for achalasia of the esophagus: results in 899 patients. Ann Thoracic Surg, 1979; 28: 119–25.

Shimi S, Nathanson LK, Cuschieri A. Laparoscopic cardiomyotomy for achalasia. J R Coll Surg Edin, 1991; 36: 152–4.

Skinner DB. Myotomy and achalasia. Ann Thoracic Surg, 1984; 37: 183–4.

Slater G, Sicular AA. Esophageal perforations after forceful dilatation in achalasia. Ann Surg, 1982; 195: 186–8.

Topart P, Deschamps C, Taillefer R, Duranceau A. Long-term effect of total fundoplication on the myotomized esophagus. Ann Thoracic Surg, 1992; 54: 1046–52.