Use of the Scissor-Type Knife During the Peroral Endoscopy Myotomy Procedure for the Treatment of Achalasia

Summary

To minimize the technical difficulty and improve the safety of peroral endoscopic myotomy (POEM), we describe a protocol for using a scissor-type knife for the main steps of POEM, including mucosal incision, submucosal tunneling, myotomy, and hemostasis.

Abstract

Peroral endoscopic myotomy (POEM) is one of the first-line treatment modalities along with pneumatic dilation and Heller myotomy for patients with achalasia. Endoscopists, especially trainees during the learning phase, commonly face difficulty in tissue plane dissection and selective myotomy while working near the esophagogastric junction, with increased risks of inadvertent injury, unexpected bleeding, and inadequate myotomy. To minimize the technical difficulty and improve the safety of POEM, we describe a protocol for using a scissor-type knife for the main steps of POEM, including mucosal incision, submucosal tunneling, myotomy, and hemostasis. The standard techniques used with the scissor-type knife involve grasping the target tissue, and then dissection or coagulation. The confirmation of the cutting line after grasping improves the accuracy and reliability of dissection, which is particularly useful for the selective myotomy of the internal circular muscle. Meanwhile, the scissor-type knife provides enhanced hemostatic capability and enables hemostasis and pre-coagulation without the device exchange for hemostatic forceps. Evaluation of the clinical outcomes in three patients who successfully received POEM using the scissor-type knife revealed no perioperative adverse events. At the 3-month follow-up, all patients achieved clinical success with postoperative Eckardt scores ranging from 0 to 1. In conclusion, the use of a scissor-type knife could minimize the technical difficulty and improve the safety of the POEM procedures, which may be suitable for trainees during the learning phase.

Introduction

Peroral endoscopic myotomy (POEM) has gained worldwide acceptance as one of the first-line treatment modalities along with pneumatic dilation and Heller myotomy for patients with achalasia¹. To date, most POEM procedures have been confined to a few high-volume, specialized centers. Previous studies have shown that even operators skilled in laparoscopy or endoscopy have a steep learning curve when they are beginning to perform POEM and a higher volume of cases is required to manage challenging situations and prevent adverse events^2,3. During POEM procedures, endoscopic needle-knives are most commonly used for both submucosal tunneling and myotomy, combined with hemostatic forceps for managing large vessels and active bleeding. However, because of the impaired esophagogastric junction (EGJ) relaxation in patients with achalasia, the limited space at the level of the EGJ increases the technical difficulty of tissue plane dissection and selective myotomy using the needle-type knife. Besides, operators who are still in the learning phase could be less proficient in exchanging the hemostatic forceps for bleeding control, which may lead to poor visibility and even further inadvertent mucosal injury.

Various endoscopic knives have been used in the POEM procedures for better manipulations and safety profiles^4,5. The junior scissor-type knife (Stag-beetle Knife Jr.) with two monopolar blades that are both insulated externally was originally developed for accurate manipulations in colorectal endoscopic submucosal dissection (ESD)⁶. The standard techniques used with the scissor-type knife involve grasping the target tissue, and then dissection or coagulation. Theoretically, tissue injury caused by unintentional movement could be avoided with a scissor-type knife as compared with a needle-type knife⁷. Several studies have demonstrated the feasibility and safety of using the scissor-type knife for all ESD procedures, including mucosal incision, submucosal dissection, and hemostasis^7,8. Meanwhile, a recent randomized controlled trial showed that the scissor-type knife significantly improved the trainees' self-completion rates for colorectal ESD⁹. It can be speculated that these advantages of the scissor-type knife can promote a safer POEM procedure, especially during the trainee's early cases. To minimize the technical difficulty and improve the safety of POEM, we described a protocol for using a scissor-type knife for the main steps of the POEM procedure, including mucosal incision, submucosal tunneling, myotomy, and hemostasis. Three patients with achalasia who received POEM using the scissor-type knife were presented to evaluate the feasibility and clinical outcomes of this protocol.

Protocol

The protocol was conducted in accordance with the Declaration of Helsinki and the protocol was approved by the Institutional Review Board at the First Affiliated Hospital of Sun Yat-sen University.

1. Patient selection

1. Diagnose achalasia by clinical manifestations and diagnostic testing (barium esophagram, high-resolution manometry (HRM), and upper endoscopy)¹⁰: the presence of symptoms such as dysphagia, regurgitation, chest pain, and weight loss; the "bird's-beak" appearance on barium esophagram; impaired relaxation of the lower esophageal sphincter and absent peristalsis on the results of HRM; and ruling out malignancy by upper endoscopy.
2. Use the following inclusion criteria: diagnosis of achalasia; Eckardt score¹¹ > 3; age between 18-80 years; written informed consent for POEM using the scissor-type knife.
3. Use the following exclusion criteria: coagulopathy and systemic disorders that precluded safe general anesthesia; pregnancy; ulcerated esophagitis.

2. Preoperative preparations

1. Administer a liquid only diet 1 day before the POEM procedure.
2. Administer intravenous antibiotics (Cefazolin) and proton pump inhibitors (PPIs) 30 min before the induction of anesthesia.
3. Perform an upper endoscopy to aspirate any residual contents to reduce the risk of aspiration immediately before the induction of anesthesia.
4. Administer general anesthesia (propofol) with endotracheal intubation.
5. Place the patient in a supine position.

3. Surgical technique with a scissor type knife for the POEM procedure

NOTE: See Figure 1 for the POEM procedure using a scissor-type knife.

1. Identify the EGJ by the puckered and tight appearance. Confirm the increased resistance when maneuvering the endoscope through the EGJ. Note the location of the EGJ by measuring the distance from the incisors.
2. Choose an injection point 7 to 9 cm proximal to the EGJ in the posterior wall (the 5-6 o'clock position) of the esophagus. Inject saline with methylene blue into the submucosal space with an endoscopic injection needle.
   NOTE: Use an extended proximal injection point for patients with Chicago type III achalasia.
3. Make a 1.5 to 2 cm longitudinal mucosal incision with the scissor-type knife (endocut Q mode: effect 3, duration 2, interval 4).
4. Rotate the blades of the scissor-type knife parallel to the muscle layer. Then grasp and dissect (endocut Q mode: effect 3, duration 2, interval 4) the submucosa tissue to create a submucosal tunnel to a location 2 to 3 cm below the EGJ. Keep the dissection plane close to the muscle layer. Inject saline with methylene blue into the submucosal tissue to expand the working space with tunnel progression.
5. Confirm the adequate submucosal tunnel length by the blue discoloration of the gastric mucosa on the retroflexed view.
6. Use the scissor-type knife for intraoperative vessel sealings and bleeding controls (forced coagulation mode: effect 2, 50 W) without changing the hemostatic forceps.
7. Begin the anterograde myotomy at approximately 2 cm distal to the mucosal entry. Selectively grasp and dissect (endocut Q mode: effect 3, duration 2, interval 4) the internal circular muscle bundle with the scissor-type knife. Extend the myotomy 2 to 3 cm onto the gastric cardia.
8. After the completion of myotomy, confirm the smooth passage through the EGJ by reinserting the endoscope into the esophageal lumen.
9. Close the mucosal entry with endoclips.

4. Postoperative management

1. Admit patients to the inpatient ward following the POEM procedure for observation.
2. Administer intravenous antibiotics for 24 h after the POEM procedure. Continue the intravenous PPIs until discharge, and then switch to the oral PPIs (single dose) for 6 weeks.
3. Initiate a liquid diet 24 h after the POEM procedure. At discharge, instruct patients to adhere to a soft diet for 2 weeks, and then resume regular diet gradually.

5. Follow-up

1. Schedule an initial follow-up by outpatient visits and telephone interviews at 3 months postoperatively.
2. At the follow-up visit, obtain standardized questionnaires from patients, including Eckardt scores¹¹, GerdQ scores¹², body weight, and information about PPIs use. Schedule objective tests, including HRM, barium esophagram, and upper endoscopy.

Results

Compared with the needle-type knife, the scissor-type knife enables coagulation and dissection after grasping the target tissue. Meanwhile, the scissor-type knife is equipped with an enhanced hemostatic capability similar to hemostatic forceps and insulated coating external of the two blades (Table 1). Three patients with achalasia received POEM using the scissor-type knife in our institution. Sigmoid esophagus was present in one patient. One patient had previously undergone pneumatic dilation. Technical...

Discussion

As an evolving endoscopic surgical treatment for achalasia, POEM requires both advanced endoscopic skills and knowledge of surgical anatomy. A recent study demonstrated that POEM comes with a considerable learning curve that increases the risk of technical failure, adverse events, and clinical failure². Endoscopists, especially trainees who have not completed their learning phase, commonly face difficulty in accurate manipulations of the endoscopic knife while working near the EGJ with limited wor...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Electrogenerator	ERBE Elektromedizin	VIO 200S
Endoclip	Micro-Tech (Nanjing)	ROCC-D-26-195-C
Endoscope	Olympus	GIF-H260
Injection Needle	Olympus	NM-400L-0423
Stag Beetle Knife Jr	Sumitomo Bakelite	MD-47703W
Transparent Distal Cap	Olympus	D-201-11804