Cardia achalasia, also known as cardia spasm and megaesophagus, is a functional disorder due to neuromuscular dysfunction of the esophagogastric junction (EGJ), characterized by lack of peristalsis, high pressure of the lower esophageal sphincter (LES) and a reduced relaxation response to swallowing movements. Clinical manifestations include dysphagia, retrosternal pain, food reflux, and cough and lung infection due to aspiration of food into the trachea.
There is a lack of epidemiological data on cardia in China, but the incidence in Western countries such as Europe and the United States is about 1 case per 100,000 people per year, with a similar ratio of men to women (1U1.15).
The cause of pancreatic achalasia is unknown, but it is generally believed to be due to neuromuscular dysfunction, associated with degeneration, reduction or lack of Auerbach ganglion cells in the esophageal muscle layer and defective parasympathetic distribution; degeneration of ganglion cells is often accompanied by inflammatory manifestations of lymphocytic infiltration, perhaps associated with infection and immune factors.
Treatment for this disease consists mainly of drugs, endoscopy and surgery aimed at reducing LES pressure and relaxing the lower esophagus, thus relieving functional obstruction.
Transoral endoscopic myotomy (POEM), a minimally innovative technique of myotomy through tunnel endoscopy, was first used in 2008 for the treatment of cardia incontinentia. China started to use POEM clinically in 2010, and after two years of rapid development, it has now become the country with the largest number of patients performing this technique.
In order to standardize the operation of POEM and provide hospitals at all levels with a preliminary specification suitable for China’s national conditions, an expert consensus on POEM for the treatment of achalasia was drafted, led by the Endoscopy Center of Zhongshan Hospital, Fudan University, following the principles of evidence-based medicine and with reference to existing domestic and international literature and expert experience. Due to the limited quality evidence-based medical evidence available at home and abroad, it is not enough to form a normative document or guideline. This consensus opinion will be updated and improved with the development of POEM and the follow-up of long-term outcomes.
Diagnosis
Clinical symptoms
Dysphagia, reflux, retrosternal pain, and weight loss are the main symptoms of cardia, and the Eckardt score, a clinical symptom scoring system for cardia, is recommended for diagnosing and grading patients with cardia (Table 1).
Dysphagia is the most common (>80%-95%) and earliest symptom; it is sometimes absent at the beginning of the disease, sometimes mild and sometimes severe, and becomes persistent in the later stages.
The incidence of food reflux and vomiting can be as high as 90%. Vomiting mostly occurs within 20-30 minutes after eating, and may involve vomiting the previous meal or overnight food. In cases of complicated esophagitis and esophageal ulcers, the reflux may contain blood. Patients can suffer from recurrent episodes of pneumonia, bronchitis, and even bronchiectasis, lung abscess or respiratory failure due to food reflux and misaspiration.
About 40% to 90% of patients have pain, mostly behind the sternum and in the mid-upper abdomen.
Weight loss is associated with dysphagia affecting food intake. Weight loss, malnutrition and vitamin deficiency are evident in patients with longer disease duration, and very few patients may present with cachexia. In the later stages of the disease, the extremely dilated esophagus compresses the intrathoracic organs and may produce a dry cough, shortness of breath, cyanosis and hoarseness.
Imaging
Barium fluoroscopy of the upper gastrointestinal tract reveals varying degrees of esophageal dilatation, decreased peristalsis, end-stenosis (bird’s beak), and smooth mucosa in the stenosis, which are typical of patients with pancreatic flaccidity.
Henderson et al. classified esophageal dilatation into three grades as follows.
Grade I (mild) esophageal diameter <4 cm; Grade II (moderate) esophageal diameter 4-6 cm; Grade III (severe) esophageal diameter >6 cm, even curved in an S-shape (sigmoid type).
Real-time barium swallow examination can quantitatively assess the ability of esophageal emptying and is a simple and easily reproducible tool for efficacy evaluation.
CT, magnetic resonance imaging and ultrasound endoscopy (EUS) can be used as a complement to barium fluoroscopy of the upper gastrointestinal tract to exclude pseudo-exhaustion of the cardia due to organic diseases such as inflammation and tumor.
Esophageal kinetic testing
Esophageal manometry is still the gold standard for the diagnosis of cardia, which is usually characterized by loss of esophageal smooth muscle peristalsis, incomplete LES relaxation, and often a significant increase in LES pressure.
Based on the results of esophageal high-resolution manometry (HRM), cardia can be divided into three types: type I (classical achalasia) shows a significant reduction in esophageal peristalsis without high intraesophageal pressure; type II shows a loss of esophageal peristalsis and a significant increase in total esophageal pressure; type III shows esophageal spasm, which can lead to luminal obstruction. This typing can be used to determine the efficacy of surgery: type II patients have the best outcome, while type III patients have the worst response to surgical treatment.
Gastroscopy
Gastroscopy can rule out organic strictures or tumors. The characteristics of endoscopic cardia atelectasis include: (1) a medium to large amount of accumulated food remains in the esophagus, mostly in a semifluid state covering the canal wall, with mucosal edema and thickening and loss of normal esophageal mucosal color; (2) the body of the esophagus is dilated with different degrees of distortion and deformation; (3) the canal wall may show a segmental constriction ring, resembling a diverticulum bulge; (4) the degree of cardia stenosis varies until complete atresia cannot be passed. In early cardia, there may be no significant endoscopic abnormality, and sometimes there is no significant resistance to pass through the cardia.
Indications for surgery
Indications Anyone with a confirmed diagnosis of pancreatic achalasia that affects quality of life can be treated with POEM.
Patients with a markedly dilated esophagus, even S- or U-shaped, those who have failed previous surgical Heller (editor’s note: thoracoscopic lower esophageal cardia myotomy) and POEM treatment or whose symptoms have recurred, and those who have undergone other treatments (such as balloon dilation, botulinum toxin injections, stenting, etc.) prior to surgery may undergo POEM, but the procedure may be more difficult.
Contraindications POEM is contraindicated in patients who cannot tolerate the procedure due to a combination of severe coagulation dysfunction or serious organic disease, and in those who cannot successfully establish a submucosal tunnel due to severe fibrosis in the submucosa of the esophagus. patients with significant inflammation or large ulcers in the lower esophagus or EGJ are a relative contraindication to POEM surgery.
Conditions and access
1. POEM should be limited to legally qualified medical units. The most basic equipment includes: endoscope with attached water-clamp tract, carbon dioxide perfusion device, transparent cap, incision knife, injection needle, thermal biopsy forceps, metal clips, etc., and special high-frequency electric generator for endoscopy. All instruments should meet the relevant sterilization requirements, disposable items should be handled in accordance with the relevant regulations, commonly used perishable instruments should have spare parts.
2. POEM must be done by legally qualified physicians, assistants and nurses in collaboration, the team should include physicians with senior technical titles, and by senior attending physicians or above, the work of formally trained personnel.
3. The main operator of POEM should have received standardized professional technical training, have experience in performing endoscopic resection, such as endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD), and complete ESD treatment of esophageal lesions in no less than 30 cases, and have experience in handling surgical complications (such as bleeding and perforation). It is recommended to operate independently after completing a certain number of cases initially under the guidance of an experienced physician, and to start with simple cases of short duration and without other treatments, and then gradually transition to the treatment of complex cases.
Pre-operative preparation
1. Complete the patient information registry through the duration of the disease, symptom score, previous treatment and various preoperative tests to clarify the diagnosis and classification of cardia inactivation and to assess the difficulty and expected outcome of the surgery. Patients with a history of severe pulmonary infection should receive preoperative pulmonary function tests.
2. Sign the informed consent form before surgery and inform the possible benefits and risks.
3. Preoperative liquid diet for 2 days. Endoscopy is performed on the day of surgery to confirm that no contents are retained in the esophagus in order to provide a good view of the operation and to prevent reflux and misaspiration during anesthesia.
Operation method and key points
Operation method
All patients received general anesthesia with tracheal intubation in the supine or left lateral position, and preoperative intravenous antibiotics were administered prophylactically. The choice of antibiotics was based on the principles of antimicrobial use of the Ministry of Health.
Esophageal mucosal layer dissection A transparent cap was attached to the front of the gastroscope to determine the distance of the EGJ from the incisors. A submucosal injection was routinely performed 10 cm above the EGJ, and the submucosal layer was revealed by a longitudinal incision of approximately 1.5-2 cm.
Separate the submucosal layer and establish a “tunnel” The submucosal “tunnel” was established by separating the submucosal layer along the esophagus from top to bottom until 2-3 cm below the EGJ, and the submucosal layer was separated as close as possible to the muscular layer, and the submucosal injection was repeatedly performed during the separation to avoid damaging the The submucosal layer was repeatedly injected during separation to avoid damage to the mucosal layer. During the separation, the mirror body was withdrawn from the submucosal “tunnel” into the gastric lumen, and the color change of the gastric mucosa was observed by inverted mirror to determine the distance between the separation stop and the EGJ. In the case of sigmoid esophagus, the esophageal wall can be flattened by the transparent cap attached to the front of the endoscope, but it is more difficult to do so.
The following indicators are used to determine whether the EGJ is reached: (1) the depth of entry; (2) the resistance to entry, which can be felt to increase when the mirror body approaches the EGJ and suddenly disappears when it passes and reaches the submucosa of the stomach; (3) the presence of fenestrated thick parallel vessels in the submucosa at the cardia; (4) the distribution of vessels in the submucosa – there are fewer vessels in the submucosa of the esophagus, while the vessels in the submucosa of the stomach are obvious. The blood vessels in the submucosa were less in the submucosa of the esophagus and more in the submucosa of the stomach in the form of spider web.
Myotomy A complete, effective and sufficiently long myotomy is the key to ensure the success of POEM. Under direct gastroscopy, the circular muscle bundle is incised 2 cm below the entrance of the “tunnel”, from top to bottom, from superficial to deep, longitudinally to more than 2 cm below the EGJ. Electrocoagulation was administered at any time to stop bleeding at the trauma site. After completion of myotomy, it was confirmed that there was no resistance to the passage of the gastroscope through the cardia. For patients with type III cardia in whom chest pain and esophageal spasm are the main manifestations, the myotomy should include all the stenotic rings caused by abnormal contractions, and the exact length of the myotomy can be judged by endoscopy or manometry; for post-Heller patients, the myotomy site is routinely chosen contralateral to the original surgical area to avoid the effect of previous surgical scar adhesions. According to the experience of more than 500 cases of POEM surgery in the Endoscopy Center of Zhongshan Hospital of Fudan University, myotomy of the whole layer, including the longitudinal muscle, can significantly shorten the operation time without increasing the surgery-related complications. To ensure long-term outcomes, total myotomy is recommended for patients with severe symptoms, especially in the 5 cm range above and below the EGJ.
Metal clips are used to close the mucosal incision. The submucosal “tunnel” and the esophagogastric lumen are aspirated, the wound is flushed and the bleeding points and small vessels are electrocoagulated; the mucosal incision is sutured with multiple metal clips.
Management of intraoperative complications
Mucosal layer injury For mucosal layer injury or even perforation during surgery, especially in the cardia, metal clamps can be used in the esophageal lumen after myotomy is completed; if necessary, a gastrointestinal decompression tube can be placed under gastroscopic surveillance.
Intraoperative emphysema, pneumothorax and pneumoperitoneum Intraoperative subcutaneous and mediastinal emphysema often requires no special treatment and can generally resolve on its own. In cases of severe intraoperative pneumothorax (airway pressure >20 mmHg and oxygen saturation <90% during surgery, confirmed by emergency bedside chest radiograph), the operation can often be continued after closed chest drainage. For those with significant intraoperative pneumoperitoneum, a 14-g puncture needle can be used to puncture and deflate the right lower abdomen at the Maier's point. Because internal carbon dioxide diffuses and is absorbed more quickly than air, carbon dioxide perfusion is recommended for endoscopic treatment, and the gas can be absorbed quickly once emphysema, pneumothorax, or pneumoperitoneum occurs. < span="">
Postoperative management
General management
On the postoperative day, fasting, fluid replacement, semi-recumbent position, and cardiac monitoring were performed to observe for cervical and anterior thoracic subcutaneous emphysema. Postoperative intravenous proton pump inhibitor (PPI) for 3 days and antibiotics (first and second generation cephalosporins are available), but the total duration of medication should not exceed 48 hours; for patients with pneumothorax, massive bleeding, advanced age and immunodeficiency, the duration of medication can be extended as appropriate.
Patients should receive postoperative chest X-ray and chest CT examination for the presence of mediastinal emphysema, pneumothorax, pneumoperitoneum and pleural effusion. Routinely, they should have a liquid diet 3 days after surgery and a semi-liquid diet 2 weeks after surgery, and take oral PPI for 4 weeks after surgery.
Complication management
Pneumothorax and pneumoperitoneum If there is mediastinum, subcutaneous emphysema and mild pneumothorax (lung compression volume <30%, patient's respiration is stable, oxygen saturation >95%, usually no special treatment is needed; for pneumothorax with lung compression volume >30%, a venipuncture catheter can be used to perform closed drainage of the thoracic cavity at the junction of the midclavicular line and the second rib space; if there is a small amount of free gas under the diaphragm and no obvious symptoms, the gas can generally be absorbed by itself If the abdominal distension is obvious, gastrointestinal decompression is feasible, and if necessary, 14G puncture needle is used to perform laparotomy for deflation.
Pleural effusion The incidence of pleural effusion after POEM is about 40%. For those who have small amount of fluid and no fever, it can be absorbed by itself without special treatment; for those who have larger amount of fluid, affecting breathing and high fever, it can be placed under ultrasound guidance to drain as soon as possible.
Bleeding The incidence of bleeding after POEM is low. Because of the richness of small vessels and collateral circulation in the lower esophageal muscular space, the wound should be flushed and electrocoagulated at any time during surgery to stop bleeding completely.
If the patient develops rapid heart rate, decreased blood pressure, progressive worsening of chest pain or vomiting of blood or black stool after surgery, the possibility of bleeding in the “tunnel” should be considered, and gastroscopic exploration should be performed in time to remove the accumulated blood from the trauma surface and submucosal tunnel, expose the trauma surface as much as possible, and stop the bleeding with hot biopsy forceps electrocoagulation; if the active bleeding point cannot be clearly identified, a three-lumen If the active bleeding point cannot be clearly identified, a three-lumen esophageal sac can be used to stop the bleeding by compression. Antibiotics should be applied therapeutically for postoperative bleeding.
Infections, mainly submucosal “tunnel” infections, mediastinal infections and pulmonary infections, are serious complications that can occur after POEM. The causes of infection include inadequate preoperative esophageal cleaning, intraoperative and postoperative bleeding and fluid accumulation in the submucosal tunnel. Therefore, the esophagus should be adequately cleaned before surgery and antibiotics should be used prophylactically; the tracheal intubation process should be prevented from aspiration; the intraoperative wound should be tightly hemostatic, and the “tunnel” entrance should be repeatedly rinsed with sterile saline before clamping to ensure that the mucosal incision is tightly clamped. For postoperative pulmonary inflammation and segmental atelectasis, strengthen sputum and administer intravenous antibiotics.
Gastrointestinal fistulae Include esophageal mediastinal fistulae and esophageal thoracic fistulae. Maintaining esophageal mucosal integrity is the key to fistula prevention. Minimize mucosal layer injury during surgery and use metal clamps to close the perforation; ensure that the entrance to the “tunnel” is tightly clamped. In case of fistula, the fistula can be occluded with an esophageal overlay stent, and closed chest drainage can be performed at the same time.
Postoperative follow-up
The purpose of follow-up is to assess outcomes, detect early recurrence, and monitor for long-term complications.
The outcome assessment is usually performed 2 to 4 weeks after surgery and includes a subjective symptom assessment and an objective examination. Subjective symptom assessment can be performed using a symptom scoring system, and surgery is considered effective if the postoperative Eckardt score is ≤3; surgery is considered a failure if the Eckardt score is ≥4 within 6 months after surgery (Table 2). Objective examinations included gastroscopy, esophageal manometry and real-time barium swallow. Gastroscopy provides insight into esophageal wound healing and resistance through the cardia port. Postoperative LES resting pressure ≤10-15 mmHg is a good predictor of long-term effectiveness of treatment. Real-time barium fluoroscopy provides insight into esophageal lumen dilation and cardia opening patency; residual barium height after 1-minute barium swallow is more than 50% below the preoperative basal value, which is also a good predictor of long-term effectiveness of treatment (Table 2).
Early detection of recurrence Those who are more than 6 months postoperative and have an Eckardt score ≥4 can be diagnosed as postoperative recurrence when combined with esophageal manometry, barium meal fluoroscopy and gastroscopy findings. Early detection of postoperative recurrence relies on regular and standardized symptom assessment. Postoperative recurrence is usually monitored by outpatient or telephone follow-up every 1-2 years after surgery with an Eckardt symptom score, or directly by periodic objective examinations. For postoperative recurrence, further treatment may be done, including re-POEM, endoscopic balloon dilatation, and placement of retrievable stents.
Monitoring of distant complications The main distant complication is gastroesophageal reflux. Patients should be followed up regularly every 1-2 years after surgery to assess the presence of heartburn and acid reflux and to determine the presence of reflux esophagitis by gastroscopy and, if necessary, 24-hour esophageal pH monitoring to confirm the diagnosis of gastroesophageal reflux (PPI is usually effective). Patients who are older, with a disease duration of 10-15 years or more, and who have recently lost significant weight should be alerted to the development of cardia cancer.