Endoscopic Submucosal Dissection and Its Clinical Application

Introduction:

Surgery is one of the most common modes of treatment for gastrointestinal cancers. But removing small cancerous growth and dysplastic lesions with a major surgical procedure can be problematic. This includes significant complications like hospitalization, bleeding, and severe pain. Such complications can be minimized with the help of modern endoscopic techniques.

What Is Endoscopic Submucosal Dissection?

Endoscopy is a procedure in which a camera-like device is inserted into the body with the help of a flexible tube-like structure. This helps in the visualization of the organs from the inside. Also, other structures can be attached to it for different diagnostic and surgical purposes. Localized excision of minimally invasive gastric cancer can be done with the help of an endoscopic technique. In this procedure, en-bloc resection of the gastrointestinal lesions can be done.

Endoscopic mucosal resection was developed by Karita et al. and Dyehle et al. in 1971. But with the help of this technique, lesions not more than 2 centimeters can be removed. To solve this issue, Hirao et al. developed endoscopic resection with a local injection of the hypertonic saline-epinephrine solution. Later in 1990, Ono et al. insulated a tipped knife in it. This is how. Endoscopic submucosal dissection was developed.

What Are the Indications of Endoscopic Submucosal Dissection?

Endoscopic submucosal dissection can be used in the treatment of various cases of gastrointestinal cancer. These are:

1. Esophageal Cancer: The cancer of the food pipe is known as esophageal cancer. This is the sixth most common cancer in the world. Smoking, excessive alcohol consumption, and gastroesophageal reflux disorder are the potential risk factors for developing esophageal carcinoma. Squamous cell carcinoma and adenocarcinoma are the principal types of esophageal cancer. Cases in which esophagectomy can not be done because of comorbid conditions are suitable for this type of surgery. Also, cases in which the lesion has spread more than three-quarters of the circumference of the esophagus can be treated using this method.

2. Colorectal Cancer: Colorectal cancer is the third most prevalent cancer in the world. The number of deaths associated with colorectal cancer is the second highest in the world. Colorectal cancers are mainly of two types: colon cancer and cancer of the rectum. Colon cancer again can be of several types, like sigmoid colon cancer, ascending colon cancer, transverse colon cancer, descending colon cancer, and cancer of the cecum. Colorectal cancer, which has spread less than 1000 micrometers below the muscularis mucosa, can be treated by this method.

3. Gastric Cancer: This type of cancer involves the lining cells of the stomach. This is the fourth most common type of cancer in the world. Adenocarcinoma of the stomach is the most common type of gastric cancer. Other types of gastric cancers are neuroendocrine carcinoma and lymphoma. Early stages of gastric can be treated by this procedure. Lesions that are less than three centimeters in size are excised through this procedure.

4. Collection samples from the lesions and analyzing them histopathologically may be misleading. For such cases, en-bloc resection of the small lesions can be beneficial in diagnosing pathological conditions.

What Are the Tools in Endoscopic Submucosal Dissection?

Endoscopic submucosal dissections depend on various instruments. These are:

1. Knives: Different types of knives are used for resection purposes. ITKnife and ITKnife2 are the most commonly used. These knives have ceramic balls mounted on the top of the cutting tips. A triangular electrode is placed beneath a ceramic ball that facilitates cutting. These knives are used for circumferential cutting. HookKnife is another type of knife where the tip is bent at a right angle to create an L-shaped device. This knife is used for hooking and retracting purposes. Circumferential incision and submucosal dissection can be possible with the help of this knife. Triangle Tip Knife also uses a triangular electrode tip for cutting purposes. FlexKnife is composed of a braided cutting knife with a looped tip at the distal aspect of the Triangle Tip Knife to avoid perforation. DualKnife uses a very small non-insulated dome-shaped electrode at the tip. This knife is used for electrosurgical purposes. HybridKnife uses a jet water stream to penetrate the submucosa. Along with this, these knives have disk-shaped electrodes and I or T-shaped knives.

2. Hemostatic Forceps and Other Devices: Monopolar or bipolar hemostatic forceps are used to stop bleeding. These forces have serrated tips with a length of 165 to 230 centimeters. These forces can also be used for grasping and cutting.

3. Dyes: Identification of pathological conditions are necessary. This helps in the proper excision of the pathological structures. Dyes like indigo carmine, methylene blue, and Lugol’s iodine are frequently used to identify neoplasms and dysplasia.

4. Injection Agents and Delivery Devices: Delineating the margins of the lesions are important for surgical excision. Such agents are delivered with 21 to 25-gauge needles. For this purpose, submucosal lifting agents are injected. These agents also provide submucosal cohesion. Though normal saline can be used, it does not provide a long-lasting cushion. Other than this, 0.4 % sodium hyaluronate and 0.4 % hydroxypropyl methylcellulose can also be used. Often these agents are mixed with dyes.

5. Endoscopes: The endoscopes used for this purpose are usually with high magnification. These endoscopes can perform narrow-band imaging that can be used for better visualization.

6. Electrosurgical Units: Electro surgical unit is the most important unit of this device. This device operated at 200 volts in an interrupted manner. This interruption is essential for coagulation.

What Are the Complications?

The complication of endoscopic submucosal dissection are:

1. One of the major complications of this procedure is bleeding. Bleeding usually occurs during the procedure. In some cases, bleeding may occur post-operative conditions also. Bleeding is most commonly seen in gastric procedures. Other than this, rectal procedures may also cause post-operative bleeding.

2. Complications caused by the surgical knife are rarely seen. But, the size of the perforation is smaller than endoscopic mucosal resection.

3. Stricture formation is most commonly seen in esophageal and gastric endoscopic submucosal dissection.

Conclusions:

Endoscopic procedures are effective for better visualization of internal structures. Endoscopic submucosal dissection is developed from the endoscopic mucosal reaction procedure. This procedure is helpful in removing small cancerous lesions without many complications. Esophageal lesions, gastric pathology, and colorectal pathologies can be removed by this procedure.