Thoracoscopic and Laparoscopic Myotomy Technique

Ernst Heller first described the two-cardiomyotomy (one anterior and one posterior) technique along the esophagogastric junction (EGJ) for achalasia in 1914. This technique has since been modified so that only an anterior myotomy is performed. Heller myotomy provides excellent results and relief of dysphagia in 90-95% of patients. ^{[11, 8]}

Traditionally, surgery was accomplished via a transthoracic or transabdominal approach. Each was associated with the morbidity of a major open procedure, often with expected hospital stays of 7-10 days. For this reason, patients commonly were treated by by means of less invasive therapies such as pneumatic dilatation, despite the superior long-term results from surgical myotomy. ^[18]

In the early 1990s, as minimally invasive techniques developed, surgical treatment came to be more widely accepted. The thoracoscopic approach was first described in 1991. This minimally invasive approach decreased postoperative pain and shortened hospital stays without compromising the relief of dysphagia.

In the mid-1990s, multiple factors led to a shift from the thoracoscopic to the laparoscopic approach, including the following:

• With the increase in the number of laparoscopic fundoplications being performed, surgeons became more adept at laparoscopically operating on and around the esophageal hiatus
• Many recognized that extending the myotomy well onto the stomach was critical for consistent and durable relief of dysphagia
• The incidence of postoperative reflux was high with the thoracoscopic approach even with limited gastric myotomy; this highlighted the need for a fundoplication, which is much easier to perform laparoscopically than via the chest

Additionally, laparoscopy avoids the need for single-lung ventilation with a double-lumen endotracheal tube and tube thoracostomy. The laparoscopic approach has been found to be superior to both open and thoracoscopic procedures with respect to complications, morbidity, mortality, length of hospital stay, relief of dysphagia, prevention of postoperative reflux, and operating time.

University of Washington experience

At the University of Washington (UW), surgeons converted from a thoracoscopic to a laparoscopic Heller myotomy in 1994 for two distinct reasons. First, the surgeons recognized that a limited gastric myotomy (0.5-1.0 cm) failed to protect the patient from gastroesophageal reflux (GER). In fact, when pH monitoring was performed, 80% of patients had pathologic reflux. Second, 17% of patients in their series returned with recurrent dysphagia, and half of them responded to extension of the gastric myotomy between 1.5 and 2.0 cm via the laparoscopic approach.

Between 1994 and 1998, 52 patients underwent laparoscopic myotomy with this longer gastric myotomy, yielding excellent improvement in dysphagia in over 90%. Still, occasional patients had inadequate relief or recurrence of dysphagia, some of whom improved with further extension of the gastric myotomy.

Therefore, the UW surgeons began extending the gastric myotomy a full 3 cm in 1998. ^[19] They also began performing a Toupet, rather than a Dor, fundoplication. They felt that an anterior fundoplication was more difficult with a 3-cm cardiomyotomy and suspected that the 270° posterior Toupet would provide better control of reflux. A comparison of the two approaches confirmed that an extended myotomy with Toupet fundoplication (EM/Toupet) more effectively obliterated the lower esophageal sphincter (LES) than the shorter myotomy with Dor fundoplication (SM/Dor). 

The evidence for this was a greater reduction in the residual LES pressure (9.5 vs 15.8 mm Hg), as well as better, more durable relief of dysphagia. Dysphagia was both less frequent (once a month vs once a week, on average) and less severe (3.2 vs 5.3 on a 10-point visual analogue scale) in the EM/Toupet group. Most important, in the subsequent 7 years, no patient required surgical intervention for recurrent dysphagia. Furthermore, this complete obliteration of the LES did not result in more reflux; the mean distal esophageal acid exposure was equivalent in the two groups (EM/Toupet, 6.0%; SM/Dor, 5.9%).

Pneumoperitoneum is usually established with a Veress needle and the use of an optical trocar. For a myotomy, four working ports are inserted under direct vision. The port for the camera is placed about 10-12 cm inferior to the left upper quadrant port and about 4-6 cm left of the midline. The remaining ports include a 5-mm trocar inserted in the right upper quadrant, a 10-mm trocar in the left lower quadrant and a 10-mm trocar in the right lower quadrant to retract the liver.

After the ports have been inserted, the patient is usually placed in a steep reverse Trendelenburg position. A 10-mm 30° angled camera is used.

The initial approach involves dividing the left phrenoesophageal and phrenogastric ligaments, allowing exposure of the left crus. Next,  the gastric fundus is mobilized to create a tension-free fundoplication. An ultrasonic dissector (eg, Autosonix; United States Surgical, Norwalk, CT) is used to divide the short gastric vessels, beginning at the inferior pole of the spleen and continuing superiorly to the previously exposed left crus.

After the left phrenoesophageal ligament is divided, the gastrohepatic ligament is incised. The right and anterior phrenoesophageal ligament and peritoneum overlying the anterior abdominal esophagus are divided, with care taken not to damage the underlying anterior vagus nerve. When a posterior Toupet fundoplication is planned, a posterior esophageal window is created. During this step, the posterior vagus nerve should be visualized and protected. If an anterior fundoplication is performed, only the anterior esophagus requires full exposure.

Adequate mediastinal esophageal mobilization is crucial for a long esophageal myotomy and tension-free fundoplication. A Penrose drain may be placed around the EGJ and used to retract the esophagus caudally and laterally during hiatal and mediastinal mobilization. To clear a path for the myotomy across the EGJ, it is useful to resect the cardioesophageal fat pad to the left of the anterior vagus nerve while simultaneously mobilizing the vagus from the esophagus. This allows a straight plane for performance of the myotomy.

Excellent visualization and exposure are essential to performing a safe and adequate myotomy. A lighted 52-French bougie is placed into the body of the stomach, serving both to illuminate the esophagus and muscle layers and to provide a stable platform for performing the myotomy. The myotomy is begun approximately 3 cm below the EGJ, and an L-shaped hook electrocautery device is used to divide the muscle fibers.

During the myotomy, electrocautery should be avoided unless absolutely necessary. Individual muscle fibers are divided by hooking them and applying gentle upward traction. Bleeding from the muscle or submucosa is controlled with pressure and time. These steps are important to avoid delayed perforation from unrecognized thermal mucosal injury.

Progressive division of the longitudinal and then the circular muscle layer is performed as the myotomy is carried superiorly, 6-8 cm above the EGJ. Once the circular muscles are divided, a mucosal plane is reached with smooth, white, bulging mucosa (see the image below). Thus, the entire myotomy spans approximately 6-10 cm (3 cm below to 6-8 cm above the EGJ). The most difficult dissection involves the 3-cm myotomy on the stomach, where the plane of dissection becomes blurred with intervening sling muscular fibers and the underlying gastric mucosa is thinner, increasing the risk of perforation.

Mucosal perforations are repaired with a fine (4-0 or 5-0) absorbable monofilament suture and rarely require further intervention. In cases with a perforation, performing an anterior (Dor) fundoplication is prudent to buttress mucosal repairs and prevent leakage or fistula formation. Endoscopy can be used to evaluate the completeness of the myotomy and check for a missed perforation.

After satisfactory cardioesophageal myotomy, a Toupet fundoplication is performed. The posterior fundus of the stomach is brought around the esophagus and secured to the right crus and the right cut edge of the myotomy. In a similar (in fact, mirror-image) fashion, the anterior fundus is sutured to the left crus and the left edge of the myotomy. Rarely, patients with large hiatal hernias require crurapexy closure of the hiatus.

Ideal length of myotomy

In general, the length of the myotomy should not exceed 6-8 cm. Sometimes, one may extend the myotomy on the proximal stomach for 2-3 cm. If a longer myotomy is performed, aperistalsis will occur, and the patient will develop severe bloating and dysphagia, which often are not reversible.

Choice of laparoscopic vs thoracoscopic approach

First, it should be understood that myotomy can be performed via either the abdomen or the thorax. The choice of approach depends on the surgeon’s training and personal preference. There is no good evidence for the superiority of one technique over the other with regard to the end result, but there are various technical differences between the two, as follows:

The first involves patient positioning. With the laparoscopic approach, the patient is placed supine, whereas with the thoracoscopic approach, the patient must be placed in the lateral decubitus position and be firmly protected by a bean bag to prevent a fall. Nerve compression injuries are also more likely with the thoracoscopic procedure. In addition, the patient needs a dual-lumen endotracheal (ET) tube, which can often add an extra 30-60 minutes to the procedure. Furthermore, there is always the risk of dislodgment of the ET tube during surgery, which technically complicates the procedure.

A second difference relates to specialty preferences. Thoracic surgeons generally prefer video-assisted thoracoscopic surgery (VATS), whereas general surgeons prefer the abdominal approach. However, if the patient is undergoing other procedures concomitantly, such as cholecystectomy, then an abdominal approach is preferred.

A third difference has to do with certain technical difficulties specifically associated with thoracoscopy. In some cases, identifying the distal LES via the thoracoscopic approach can be difficult, especially in obese individuals. In addition, extending the myotomy to the proximal stomach can also be problematic via thoracoscopy. For patients who have undergone multiple abdominal procedures, the presence of adhesions may make a thoracoscopic approach more practical and safer.

A fourth difference concerns the degree of postoperative pain and morbidity. The pain after a laparoscopic procedure is significantly less than that after a thoracoscopic one, and if by chance the procedure must be converted to an open operation, a thoracotomy is associated with much higher morbidity than a celiotomy is.

A fifth difference is that adding a reflux procedure is also slightly more difficult via the thoracoscopic approach.

In conclusion, as surgeons become more experienced with minimally invasive procedures, it is to be hoped that they may become skilled in both laparoscopic and thoracoscopic approaches to myotomy. No matter which procedure the surgeon elects to perform, the key is to ensure patient safety.

For patients who have recurrence of symptoms, those whose myotomy was inadequate, or those who underwent a prior thoracoscopic myotomy, laparoscopic surgery is the procedure of choice. The procedure allows extension of the myotomy and performance of an additional reflux procedure if required.

To ensure that the dysphagia caused by achalasia is effectively relieved, complete division of the LES muscles is necessary.

Thoracoscopic long myotomy has been performed with moderate success in patients with diffuse esophageal spasm. ^[20]

It must be kept in mind that a thoracic approach to myotomy does not allow complete extension of the myotomy to the cardia, which is a common reason for recurrence of dysphagia. Redo surgeries are generally more difficult and do require advanced laparoscopic skill and a good understanding of the abdominal and thoracic anatomy.

If the patient has had a myotomy and has recurrence but is not a candidate for surgery, pneumatic dilatation is another noninvasive option. Botulinum toxin has been used to treat achalasia and is an option for patients who are poor candidates for surgery. It should not be used in good surgical candidates, because it induces severe fibrosis and makes surgery difficult. The intense fibrosis often lasts 6-12 months.

With the advent of minimally invasive surgery, laparoscopic Heller myotomy now is the first procedure of choice for most patients. ^{[21, 22, 23]}

Robot-assisted surgery has also been used to treat achalasia. ^[24] Robotic surgery can perform both an anterior reflux procedure and a myotomy without assistance. The chief advantages of robotic surgery include greater flexibility, better visualization, increased range of motion of instruments, and ease of fine manipulations in tiny spaces.

The anatomy of the esophagus lends itself well to robotic surgery because the approach is direct and allows the robotic arms a full range of mobility and flexibility. Once the instruments are inserted, not much maneuvering is required except fine dissection.

To date, however, there have been no studies comparing robotic surgery with manual laparoscopy in the treatment of achalasia. The definitive feature of robotic surgery in this setting is its prohibitively high cost.

Early

Perforation of the esophagus is known to occur in 1-5% of cases. The vast majority of perforations are identified in the operating room and easily repaired with minimal morbidity and no affect on the relief of dysphagia. This is vastly different from the morbidity associated with esophageal rupture that occurs following balloon dilatation for achalasia

Additional complications of surgery seen in 3% of patients include bleeding, pneumothorax, wound infection, and ileus. The pneumothorax rarely requires treatment except for observation with serial chest radiographs. Other rare complications include splenic injury and injury to the vagus nerve.

Late

Late complications from the surgery include recurrent dysphagia. Other common complications include incomplete myotomy, scarring in the hiatal region, and stricture formation.