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Laparoscopic cardiomyotomy for achalasia

SHERAZ MARKAR AND GIOVANNI ZANINOTTO

INTRODUCTION AND HISTORICAL NOTES

Esophageal achalasia, albeit a rare disease with an incidence ranging from 0.4 to 1.5 per 100 000 inhabitants/year, is the most characterized esophageal motor disorder and it is defined by the failure of the lower esophageal sphincter to relax at swallowing and by the absence/impairment of peristaltic contractions along the esophageal body. As a direct consequence, a residual pressure gradient between the esophagus and the stomach remains after swallowing, causing a functional obstruction at the gastro-esophageal junction. Dysphagia, regurgitation of undigested food, respiratory symptoms (nocturnal cough, recurrent aspiration, pneumonia), chest pain, and weight loss are the most common symptoms experienced by the patients. Present understanding suggests that achalasia results from the disappearance of the myenteric neurons that coordinate esophageal peristalsis and lower esophageal sphincter relaxation. It is believed the myenteric neurons disappear due to chronic ganglionitis, with experimental data suggesting that in genetically predisposed patients, an aberrant autoimmune response to the herpes simplex virus may be the trigger leading to achalasia.

Due to the absence of an etiologic therapy, the medical community has focused treatment around how to palliate dysphagia, the main symptom of achalasia. This is done by lowering the lower esophageal sphincter pressure, either by forceful dilatation, by sectioning the lower esophageal sphincter muscle, or by paralyzing it with Botulinum toxin.

For many years, surgery has represented the most effective therapy for achalasia. The original treatment was proposed by a German surgeon, Heller, in 1914. The myotomy as described by Heller was performed in April 1913 on a 49-year-old patient who had been suffering from dysphagia for more than 30 years. It consisted of two separate longitudinal incisions 8 cm long on the anterior and posterior sides of the esophagus and cardia, through a left subcostal approach. Some years later, a Dutch surgeon, de Bruyn Grenwaldt, limited the procedure to the anterior myotomy (though this adaptation is attributed to another Dutch surgeon, Zaaijer). The modified technique with only the anterior myotomy has remained substantially unchanged ever since and the procedure has continued to be linked to the name of Heller. After the advent of thoracic surgery, the operation was performed in English-speaking countries through a thoracotomy, while in continental Europe and South America, the abdominal approach continued to be preferred. In the 1960s, a French surgeon, Dor, suggested adding a partial anterior gastric fundoplication to the myotomy to prevent acid reflux.

In the following years, the preferred treatment for achalasia shifted toward the less invasive option, endoscopic pneumatic dilatation (PD), but the advent of mini-invasive surgery in the early 1990s revived the Heller myotomy, and the pendulum of achalasia treatment swung back in favor of surgery. The first mini-invasive Heller myotomy was performed in Dundee by Cuschieri via a laparoscopic approach. Two years later, Pellegrini reported performing the same operation through a thoracoscopic approach, and Ancona subsequently added an anterior fundoplication to the laparoscopic myotomy. Since then, the operation has gained in popularity and is now considered the gold standard treatment for esophageal achalasia.

DIAGNOSIS AND SURGICAL TECHNIQUE

DIAGNOSTIC WORK-UP

Diagnostic work-up comprises esophageal high resolution manometry (HRM), barium swallow, and endoscopy. HRM provides detailed information on esophageal motility: using catheters incorporating 36 or more pressure sensors spaced 1 cm apart, it allows in-detail pressure recording from the pharynx to the stomach, and is currently considered the gold standard investigation to diagnose achalasia. The use of HRM has led to the subclassification of achalasia into three clinically relevant types based on the pattern of contractility in the esophageal body: type I (classical achalasia; no evidence of pressurization), type II (achalasia with compression or compartmentalization in the distal esophagus >30 mmHg), and type III (two or more spastic contractions). To quantify lower esophageal sphincter relaxation, a new manometric parameter was introduced: integrated relaxation pressure (IRP). This parameter calculates the mean post-swallow lower esophageal sphincter pressure over a 4-second period during which the lower esophageal sphincter pressure is at its lowest. The upper limit of normal for IRP is 10 mmHg for type I achalasia, 15 mmHg for type II achalasia, and 17 mmHg for type III achalasia, which differentiates the impaired relaxation in achalasia from non-achalasic individuals and from diffuse esophageal spasm patients.

The classical radiographic features of achalasia seen on contrast swallow investigations are esophageal dilatation and minimal lower esophageal sphincter opening, with a bird’s-beak appearance of the cardia, sometimes with an air-fluid level in the gullet and no intragastric air bubble. In more advanced achalasia, severe dilatation with stasis of food and a sigmoid-like appearance can be noted. A “timed” barium swallow test has been proposed and is widely utilized in evaluating patients before and after treatment. A fixed amount of barium (200 mL) is ingested in 2 minutes, and pictures are taken after fixed intervals (at time 0, then after 1 minute, 2 minutes, and 5 minutes) to measure the height of the barium column.

Endoscopy is most commonly the primary investigation to be performed in a patient with dysphagia. Findings may appear normal in patients with achalasia, especially in the early stages, when the gullet is only mildly dilated. In more advanced cases, esophagitis (“stasis” esophagitis) may be identified and should not be confused with reflux esophagitis. Esophageal candidiasis, resistant to the usual treatments, can also be found, and is usually related to the functional obstruction. Malignant tumors can produce an achalasia-like syndrome called “pseudoachalasia” by infiltrating the gastro-esophageal junction and mimicking the clinical and manometric presentation of achalasia; they account for about 5% of cases of misdiagnosis. In general, patients with pseudoachalasia are older and have a shorter history of dysphagia and weight loss. Endoscopy, with a careful examination of the cardiac and fundic region, is therefore mandatory as part of the diagnosis work-up to avoid this potential catastrophic pitfall and, if the clinical suspicion is strong, computerized tomography and endoscopic ultrasound should be considered. These latter tests should be considered particularly in elderly patients with symptoms of recent onset.

Finally, all the tests routinely performed as part of preoperative assessment before surgery under general anesthesia (blood tests, chest X-rays, electrocardiogram) are required. Additional tests may be requested by the anesthesiologist for particular patients, based upon specific issues raised by the patients’ physiological status and/or medical comorbidities.

Patient preparation and positioning

Patients should be kept on a liquid diet for 24 hours before the operation, and a dilated gullet should be mechanically washed and emptied via a naso-esophageal tube the night before the procedure. The required standard laparoscopic instrumentation is composed of two 12 mm trocars and three 5 mm trocars; a 30-degree laparoscope; a device for lifting the left liver lobe; atraumatic forceps, a cautery hook, scissors, and a needle holder for suturing. Small bipolar cautery forceps may be useful to control bleeding from the edges of the myotomy. The endoscope may be useful during the performance of the myotomy to facilitate the procedure and check for any mucosal perforation. We prefer to position endoscopically a guide wire in the stomach before starting the operation and to place a 3 cm Rigiflex balloon (Boston Scientific, Marlborough, Massachusetts, United States) across the cardia during the myotomy.

The operation is performed under general anesthesia and oro-tracheal intubation. The patient is placed supine on a steep reverse Trendelenburg position with legs abducted and the surgeon standing in between. The right arm is tucked against the patient’s side and the left arm remains on an arm board. Prophylactic anti-thrombosis measures (low molecular weight heparin and stockings) are recommended.

Pneumoperitoneum is created using open technique, and the first 12 mm trocar for the laparoscope is positioned in the midline, halfway between the umbilicus and the xyphoid. A 5 mm trocar is inserted as laterally as possible on the patient’s right side, immediately below the costal margin, to lift the left lobe of the liver. A 5 mm trocar inserted immediately below the xyphoid is used for the operator’s left hand, while a 12 mm trocar inserted laterally below the left costal margin provides access for the surgeon’s right hand. Finally, a 5 mm trocar is positioned on the left mid-clavicular line to pull down the gastric fundus (see Figure 41.1).

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