Thoracoscopic and Laparoscopic Myotomy

Achalasia is an uncommon disorder of the esophagus. The disorder is characterized by inadequate relaxation of the lower esophageal sphincter (LES) and concomitant loss of peristalsis in the body of the esophagus. (See the images below.) Patients are usually young and often present with dysphagia to both solids and liquids at the same time. Other symptoms may include regurgitation, chest pain, aspiration, and weight loss. The disorder is often mistaken for gastroesophageal reflux (GER) disease (GERD), and this mistake is a common reason for a delay in diagnosis of achalasia.

Achalasia is most common between the second and fifth decades of life but has been reported in people of all ages. ^[1] In the United States, the incidence is about 1 per 200,000 population.

With achalasia, the essential problem involves lack of normal esophageal motility and a hypertonic LES that fails to relax. The aim of surgery is to disrupt the muscle fibers of the LES to relax the esophagus and allow for passage of food.

Today, many surgeons offer a laparoscopic procedure for the treatment of achalasia. Studies have shown that this surgery offers durable results with good short-term benefits. More than 90% of patients have relief of their symptoms immediately after surgery. In addition, the use of minimally invasive surgery has reduced the morbidity associated with open esophageal surgery. A thoracoscopic procedure has also been performed. (See Technique.)

There are many treatments for achalasia. Over the years, the role of surgery has become better defined. For mild cases of achalasia, medical therapies still play a role. Even though several medical therapies are available, the response is variable among patients, and the benefits are not sustained for longer than a few months, at best. Botulinum toxin and pneumatic dilatation may be good choices in patients who want to wait or would like a nonsurgical alternative. However, repeated balloon dilatation is associated with a risk of esophageal perforation, which appears to occur in 1-3% of cases.

Minimally invasive surgery has now supplanted most medical therapies for achalasia. ^{[2, 3, 4, 5, 6, 7]} The minimally invasive approaches have a far lower morbidity and mortality than the open technique does. More than 90% of patients find effective relief from dysphagia. For those who have associated GERD, an antireflux procedure can be combined without any added morbidity.

Etiology of achalasia

Achalasia has been known to occur for more than 200 years, but its cause still remains unknown. Biopsy of the mucosa in the affected part of the esophagus often reveals loss of ganglion cells and fibrosis of myenteric plexus.

This process is likely autoimmune-regulated, given that T cells predominate in the inflammatory infiltrate. ^[8] Additional research has shown that achalasia patients have decreased nitric oxide synthase in the myenteric plexus, resulting in reduced nitric oxide production. ^[9] Because nitric oxide is a key factor in gastrointestinal (GI) smooth-muscle relaxation, its decreased presence at least partly explains the dysfunction of the LES.

Symptoms of achalasia

The hallmark symptom of achalasia is progressive dysphagia, often first to solids and then to liquids. Because the dysphagia usually worsens very gradually, it is often quite severe upon presentation. Most patients adapt their eating behavior long before the diagnosis is made. Because stress and cold liquids may exacerbate the dysphagia, both liquids and solids may be poorly tolerated simultaneously at presentation.

Chest pain is also a common symptom, and patients often undergo extensive cardiac evaluation prior to diagnosis. Previously, 10-39% of patients suffered bronchopulmonary complications from repeated regurgitation and aspiration. ^[10] Many of these complications can now be avoided through earlier diagnosis and treatment. Dyspepsia occurs in about one fourth of cases, though it is usually caused by fermentation of unevacuated food in the esophagus rather than GER. ^[11]  

Also common, though often not mentioned, are the symptoms caused by fungal infection. The residual food in the esophagus makes this structure a prime target for Candida, and the resulting infection can be quite severe. Medical treatment is required to manage the candidal infection, but recurrence is common as long as achalasia persists. ^[12]

Patients often have a long history of symptoms—in some cases, longer than 30 years. Weight loss is common, though patients usually alter their diets enough to maintain body mass until the disease becomes intolerable and they seek therapy. Acute onset of symptoms or rapid weight loss should be a red flag for clinicians to rule out malignancy. Ruling out pseudoachalasia (presence of a distal esophageal tumor causing dysphagia) in older patients (>55 y) is crucial, ^[13]  as is ruling it out in those with a shorter duration of symptoms (< 6 mo), or more profound, rapid weight loss (>15 lb [~7 kg]).

Any patient with a questionable diagnosis should undergo a careful evaluation, to include the use of endoscopic ultrasonography (US) and computed tomography (CT) to rule out pseudoachalasia. ^[11]

Sigmoid-shaped esophagus or megaesophagus

Some patients with achalasia develop a megaesophagus, which is usually the end stage of achalasia. This disorder is characterized by an aperistaltic esophagus and failure of the LES to relax. Over time, progressive dilatation and lengthening of the esophagus occurs. In the past, the only surgical option these patients had was total esophagectomy because no matter what type of surgery was performed, the dilated and tortuous esophagus had no motility and dysphagia persisted.

In the past decade, some surgeons have been offering laparoscopic myotomy to these patients. The myotomy significantly lowers the morbidity and mortality that is associated with a total esophagectomy. Initial studies indicated that laparoscopic myotomy was beneficial in these patients and provided moderate-to-excellent relief of symptoms. Short-term evaluation of these patients revealed no reflux and improvement of dysphagia. Unfortunately, the majority of these reports are anecdotal case reports. There remains a need for long-term data. 

To be able to undergo a laparoscopic myotomy under general anesthesia, the patient must be surgically fit. A relative contraindication may be prior esophageal or hiatal hernia surgery. Some surgeons feel that a megaesophagus or grade 1V dilatation (>8 cm) is a contraindication for myotomy because poor relief from dysphagia occurs. Instead, these patients may be better served with an esophagectomy.

Another group of patients who may not be served well with surgery are the elderly. These patients may best be managed with medical therapies (eg, botulinum toxin or dilatation). 

In any case, other surgeons feel that a minimally invasive procedure may be attempted, and an esophagectomy can then be performed if the minimally invasive procedure fails.

Best practices

No absolute rule exists regarding the extent of the myotomy. In the past, most surgeons have elected to perform a myotomy of 3-5 cm. (See the image below.) However, numerous studies have shown a direct correlation between length of myotomy and relief from dysphagia. Ample evidence shows that a myotomy shorter than 1 cm on the gastric wall is associated with persistent dysphagia. Most experts recommend making a myotomy of about 1.5 cm over the gastric wall to ensure that no residual dysphagia exists. Some surgeons also recommend that extending the myotomy to about 3 cm has better outcomes, but long-term results with this approach are unavailable.

A controversial aspect of laparoscopic myotomy is whether to perform an antireflux procedure at the same time. Some surgeons recommend performing a simultaneous antireflux procedure each and every time, but others maintain that the addition of the procedure should depend on the patient and the status of the esophagus. ^[14]

Long-term outcome data from the open surgical era have suggested successful relief of dysphagia in 65-70% of patients. However, most of these patients underwent open thoracotomy with minimal extension of the myotomy onto the stomach. This lack of sufficient myotomy onto the cardia has been proved to be the cause of most recurrent dysphagia after thoracoscopic or open myotomy via the chest. Additionally, many of these late failures were the result of severe, intractable reflux affecting quality of life and necessitating surgical intervention. ^[15]

Since the advent of the abdominal approach, and because laparoscopic techniques greatly improve visualization and allow longer transabdominal myotomies, success rates have improved dramatically. Several authors have now supported performing the myotomy with intraoperative endoscopic or manometric guidance to ensure complete obliteration of the LES. Specifically, the sling fibers of Willis (the oblique component of the LES) must be surgically divided to provide adequate passage of food.

Transthoracic approaches also make performing an antireflux procedure more difficult. These problems have been substantially corrected with laparoscopic techniques. Long-term outcomes for dysphagia in patients undergoing a laparoscopic Heller myotomy and antireflux procedure have ranged from 80% to 95% in large studies. Results for control of reflux may be inferior to results for dysphagia.