Robotic Heller Myotomy for Advancements in Surgical Management of Achalasia

Achalasia is an esophageal motility disorder. The most common cause of achalasia is idiopathic, characterized by impairment of the circular and longitudinal muscular layers of the esophagus due to the destruction of the myenteric nerves in the lower esophageal sphincter (LES)¹. This leads to the inability of the LES to relax. Achalasia is also associated with an increased risk of esophageal squamous cell carcinoma. The gold standard for diagnosing achalasia is manometry^2,3. However, endoscopy should be performed to rule out other causes of narrowing, such as gastro esophageal junction (GEJ) malignancy and other strictures.

The treatment of achalasia is divided into surgical and non-surgical options. Non-surgical treatments include the use of drugs such as calcium channel blockers and nitrates, as well as endoscopic treatments like dilation or botulinum toxin injection. Non-surgical treatments have high recurrence rates^4,5. Surgical treatment, specifically laparoscopic or robotic myotomy, originally described as the heller myotomy, can be performed with or without an anti-reflux procedure. Surgical treatment provides the best long-term treatment and relieves achalasia symptoms by dissection of the muscles in the affected part of the esophagus around the LES⁶.

The decision to perform a fundoplication following Heller myotomy remains controversial. In theory, anti-reflux procedures, such as the Dor or Toupet procedures, reduce the risk of gastroesophageal reflux disease (GERD) following myotomy. Peroral endoscopic myotomy (POEM) has been developed as an option in the treatment of achalasia. Through a proximal submucosal tunnel, the muscular layer of the affected esophagus is divided distally to the level of LES and cardia⁷. We perform the Heller myotomy using a robotic approach. The robotic platform offers enhanced high-definition visualization of distal esophageal and hiatal anatomy, advanced range of motion, and decreased complication rates when compared to the laparoscopic approach⁸. Despite all the advantages of the robotic approach, the method and approach to surgical treatment of achalasia decision ultimately lies with the surgeon and is dependent on the available resources, level of comfort, and experience with the available techniques. The goal of this protocol is to serve as a guide and a valuable resource for training new foregut surgeons, as well as residents, making the steps of the surgery clear and understandable.

This protocol follows the guidelines of our institution's human research ethics committee. Written informed consent was obtained from the patients' cases reviewed for the protocol. Inclusion criteria - patients of all ages who were diagnosed with achalasia based on clinical manifestations, manometric criteria, and radiographic studies. Exclusion criteria - achalasia symptoms due to gastroesophageal malignancy.

1. Preoperative preparation

1. Place patients on a liquid diet for 3 days prior to the operation in an attempt to clear the esophagus of impacted food.
2. Place the patient in the supine position and administer general endotracheal anesthesia (GETA) via a rapid sequence induction (RSI) while holding cricothyroid pressure to reduce the risk of aspiration during intubation. To provide Cricothyroid pressure, apply manual pressure on the cricoid cartilage to occlude the esophagus.
   NOTE: The RSI technique is conducted via the administration of appropriate anesthetic agents and neuromuscular blocking agents per the anesthesiologist's protocol.
3. After successful endotracheal intubation, perform an esophagogastroduodenoscopy (EGD) to assess the level of achalasia severity and dislodge any solid food stuck in the esophagus, if needed (Figure 1A).
   1. Ensure the endoscope is clean and properly connected to the video monitor and light source. Confirm that the water and air channels are functioning correctly, lubricate the distal end of the endoscope to facilitate insertion, and then gently insert the endoscope through the patient's mouth into the esophagus under direct visualization.
      NOTE: Usually, there is a pop of pressure as the endoscope is passed through the gastroesophageal junction with pressure.
4. Leave the endoscope in the stomach to function as a bougie and provide counter pressure within the esophagus during the myotomy procedure.

2 Ports placement and robotic docking

NOTE: A total of four 8 mm robotic ports are required for the surgery, and there is an option to add a fifth port to serve as an assistant trocar.

1. Following skin sterilization and preparation using an antiseptic solution, perform a small skin incision of approximately 1 cm using a blade at each planned trocar insertion site in order to insert the trocar into the abdominal cavity.
2. Place the first port site at 15 cm below the xiphoid process, 1-2 cm to the left of the abdominal mid-line, using a 0° 5 mm laparoscope and optical access trocar visualization technique. Use a verses needle to inflate the abdomen when needed.
3. Attach carbon dioxide gas insufflation and inflate the abdomen to 15 mmHg. Reinsert the 0° scope and inspect the abdomen for any site of potential trocar injury. Change the laparoscope to 30° to facilitate additional trocar placement.
4. Under direct vision, place three 8 mm robotic trocars in a transverse line at the level of the first port with 4-8 cm between each port (try to leave 8 cm between each port to reduce collisions within the robotic arms). Locations of robotic ports (from patient left to right) are approximately at the left anterior axillary line, left mid-clavicular line, and right mid-clavicular line (Figure 2).
5. Place an additional assistant trocar in the right flank at the level of the right anterior axillary line, just above the level of the umbilicus.
6. Place a Nathanson liver retractor in the xiphoid region to elevate the left lateral lobe of the liver and expose the hiatus. This will expose the entire left upper quadrant, ensuring excellent exposure for the operation.
7. Dock the robot. Prepare the instruments, which include an advanced bipolar energy device, a cardia forceps, a fenestrated bipolar, and a hook cautery.

3 Division of phren-oesophageal ligament

1. Divide the gastrohepatic ligament using the bipolar energy device to expose the right crus and phren-oesophageal membrane (Figure 3).
2. Identify the phreno-esophageal membrane and divide it using the bipolar energy device toexpose the longitudinal muscle fibers of the esophagus. Extend and dissect the avascular plane between the esophagus and mediastinum from the right crus to the left crus after dividing the phren-oesophageal ligament.This dissection should expose the anterior surface of the esophagus.
3. Identify and preserve the anterior vagus nerve. Elevate and dissect the anterior vagus nerve off of the esophagus to facilitate the preservation of the nerve and to ensure a complete myotomy beneath the nerve .

4 Esophageal myotomy

1. Dissect the gastroesophageal fat pad on the anterior surface using an electrocautery hook from the level of the stomach to expose the GEJ; start the dissection at the distal fat pad.
2. Extend the dissection proximally to the left crus using an electrocautery hook, and then medially dissect towards the right crus with care to preserve and protect the anterior vagus, which often courses through the medial aspect of the fat pad.
3. Before performing the myotomy, completely expose the distal portion of the esophagus and the anterior portion of the proximal stomach to allow for the appropriate length of myotomy.
   NOTE: The goal for myotomy length should be a minimum of 6 cm in the distal esophagus and 2 cm in the proximal stomach.
4. Begin the myotomy just proximal to the GEJ on the side of the esophagus, approximately 1 cm proximal. This approach will help the surgeon avoid the sling fibers of the stomach, which can occasionallycause confusion during dissection.
5. Exchange the robotic advanced bipolar instrument for the robotic hook. With great care, start the myotomy 1 cm proximal to the GE junction with a brief application of cautery energy with the robotic hook. Using traction of the robotic hook towards the anterior abdominal wall, carefully divide the esophageal muscle fibers until the esophageal mucosa is visualized.
6. After the mucosa is visualized, repeat the traction motion of the hook (with minimal use of cautery) to tear the esophageal muscular fibers proximally onto the esophagus. Continue dissection until either the view becomes obstructed or the dissection has reached a point where repairing an injury would be challenging. Ensure that it is at least 6 cm in length (Figure 4 and Figure 5).
7. After completing the proximal myotomy, continue the dissection down onto the side of the stomach.
   NOTE: A technical consideration during myotomy is to prioritize the tearing of muscle fibers rather than using cautery. This helps to minimize the risk of thermal injury. However, if cautery is used, it is recommended to pull the circular fibers away from the esophagus before applying cautery. (Figure 4)

5 Post-myotomy esophago-gastro-duodenoscopy

1. Perform an EGD to evaluate the GEJ. Ensure that the endoscope easily passes across the cardia and use visual inspection to ensure that there is no thermal injury (Figure 1B).
2. Perform a leak test by inflating the esophagus and stomach with air while submerging them in water. Evaluate for the presence of gas bubbles, which could indicate a leak.
3. After completing the myotomy,proceed with a Dor to Toupet fundoplication if indicated.
   NOTE: If a Toupet fundoplication is performed, posterior dissection of the hiatus is necessary. However, if a Dor fundoplication is to be performed, there is no need to disturb the posterior attachments of the esophagus.
4. Upon completing the procedure, remove the endoscope along with the liver retractor and ports.

6 Post-operative care

1. In the postoperative period, administer a multi-modal pain regimen with anti-inflammatory and opioid medications. Start patients with a clear liquid diet on the day of surgery. On postoperative day 1, perform a radiographic evaluation with an upper GI series to evaluate for leaks (Figure 6B). Most patients are discharged on postoperative day 1 with instructions to follow a full liquid diet until post-operative evaluation in the surgery clinic within 2 weeks.

At our academic tertiary care center, both intraoperative and postoperative complications of Heller myotomy are extremely rare. Between 2020 and August 2023, post-Heller myotomy perforation rate was 0% utilizing the robotic approach. During this period, we performed 105 robotic Heller myotomy. Blood loss is generally less than 20 mL, and we did not transfuse blood for any patient; hospital stay length rarely exceeds postoperative day 1, and patients are able to drink immediately after surgery, experiencing relief of their achalasia symptoms. After the myotomy, we routinely perform intraoperative esophagogastroduodenoscopy (EGD) to evaluate the gastroesophageal (GE) junction. During this examination, we ensure that the endoscope can easily pass across the cardia (Figure 1B), and we can rule out any injury using a leak test. In recent years, we have begun to utilize endoluminal functional lumen imaging probes during the operation. Our patient was chosen randomly. She is a 67-year-old with a history of psoriatic arthritis and type II Achalasia. She had been suffering from progressive dysphagia, even after a previous attempt to treat it with Botox and dilation. The procedure (Heller myotomy) was performed successfully without any complications, and no blood transfusions were needed. She was able to drink immediately after the procedure and felt obvious relief from the dysphagia. After the surgery, she was discharged home on postoperative day 1. These results following surgery allow us to be confident of a safe and complete myotomy (Table 1). The radiographic evaluation of the upper GI series done before the operation and on post-operative day 1, showing the removal of the strictures and the absence of any leaks, is depicted in Figure 6.

Figure 1: Esophagogastroduodenoscopy. (A) Preoperative esophagogastroduodenoscopy (EGD) was used to visualize the severity of achalasia and rule out other findings (GEJ malignancy and other strictures). (B) Post-myotomy esophagogastroduodenoscopy (EGD) was able to pass the endoscope across the cardia easily, and no thermal injury was found. Please click here to view a larger version of this figure.

Figure 2: Trocars placement. From the patient's left to right, the picture depicts the arrangement of 4 robotic trocars spaced approximately 8 cm apart. In addition, there is an assistant trocar positioned at the level of the right anterior axillary line. Furthermore, a Nathanson liver retractor is visible in the xiphoid region. Please click here to view a larger version of this figure.

Figure 3: Gastrohepatic ligament division. Division of the Gastrohepatic ligament, exposing the right cruse and phren-oesophageal membrane, using the bipolar energy device. Please click here to view a larger version of this figure.

Figure 4: Esophageal myotomy. The picture shows the application of traction using a robotic hook towards the anterior abdominal wall while carefully separating the muscle fibers of the esophagus until the esophageal mucosa becomes visible. Please click here to view a larger version of this figure.

Figure 5: Complete esophageal myotomy. The picture illustrates a complete esophageal myotomy spanning at least 6 cm, highlighting the preservation of the anterior Vagus nerve branch indicated by an arrow. Please click here to view a larger version of this figure.

Figure 6: Upper GI series. (A) This picture demonstrates a dilated esophagus and an EGJ stricture after ingesting barium during a GI series. (B) Following Heller myotomy, we can observe a significant relief in esophageal dilation and a significant improvement of the GEJ stricture with the passage of barium. Additionally, no evidence of a leak or free air was found. Please click here to view a larger version of this figure.

Table 1: Patient demographic and operation parameters.

Laparoscopic and robotic Heller myotomy is now the procedure of choice with or without fundoplication⁶. The primary contentious issues revolve around the necessity of fundoplication after Heller myotomy, as well as the type of fundoplication (Toupet, Dor, Nissen) to minimize GERD. Peroral endoscopic myotomy (POEM) is another option for achalasia treatment; however, this option lacks a fundoplication procedure⁸. Therefore, surgeons should make decisions regarding which procedures to perform based on their own experience and preferences. The critical point in myotomy is to obtain enough length of myotomy on both the esophageal and gastric sides. The gastric side myotomy is, at times, more challenging than the esophageal myotomy as there is now a serosal layer of the stomach wall, and the gastric sling fibers are present as well. During this dissection, it is also common to encounter large submucosal veins feeding into the left gastric venous system. If bleeding is encountered, it is recommended to use pressure and a thrombotic agent to stop the bleeding. Additionally, caution should be taken while using hook cautery to avoid injury to the esophageal mucosa and to prevent perforation⁹. If there are issues with exposure of the mediastinum during esophageal myotomy, the anterior portion of the diaphragmatic hiatus can be divided to increase exposure. However, if this is done, this should be closed with a permanent stitch at the completion of the case.

The advantages of robotic surgery compared to others are enhanced dexterity and greater precision due to better visualization with the three-dimensional view. Additionally, it gives the surgeon the ability to operate even in tight spaces, hence its utilization in pelvic surgery. A meta-analysis study showed a lower intra-operative perforation rate with robotic Heller myotomy compared to laparoscopic surgery (0% vs. 11%, respectively)¹⁰. The disadvantage of the robotic approach is reported higher cost¹¹. The limitations of the laparoscopic approach include a poor range of motion and limited view and visual stability when compared to robotics.

In conclusion, in the hands of experienced surgeons, robotic surgery is safer and yields exceptional results due to its improved visualization, platform stability, and increased articulation of the instruments.