Titanium Clip and Dental Floss Traction Assisted Endoscopic Submucosal Dissection Resection for Early Gastric Cancer

Summary

This study presents a successful technique using a titanium clip and dental floss traction-assisted endoscopic submucosal dissection for the treatment of early gastric cancer.

Abstract

Endoscopic mucosal dissection (ESD) is used to diagnose and treat early gastrointestinal tumors. ESD allows for curative resection of superficial gastrointestinal lesions, with the advantage of treating multiple lesions in a single session and performing repeated procedures when necessary. However, ESD operations require a large field of view, and when bleeding occurs, the restricted space may make it difficult to locate and control the bleeding site in a timely manner. Larger wounds created during ESD procedures require even more space, and while tunneling technology has emerged, it is still considered less direct compared to having an additional hand to open the peeled mucosal window. Although transparent caps can help expose the surgical field, their effectiveness is limited when dealing with larger wounds. Various auxiliary techniques have been explored to address these challenges. In our endoscopic diagnosis and treatment center, we have been using ESD for many years, performing approximately 200 cases annually of gastric mucosal lesions and submucosal masses. The vertical and horizontal margins were negative, and the resection was complete, avoiding surgical treatment. Among these cases, 10 involved the use of dental floss-assisted traction during ESD. Dental floss assistance, as one of the auxiliary ESD methods, has the advantages of convenience and ease of use, which facilitates the imaging process. By securing the tail of a titanium clip with dental floss, the procedure becomes more efficient and adaptable. The traction wire can be pulled as needed during the operation, helping to expose and control the field of view. This significantly supplements the effect of the transparent cap, which may be less effective in larger wound areas. Dental floss traction acts as a third hand, expanding the operational space, facilitating endoscopic maneuvers, reducing surgical time, and minimizing the risk of side injuries during the treatment.

Introduction

Endoscopic submucosal dissection (ESD) is a minimally invasive method for treating early gastrointestinal cancer and precancerous lesions¹. It involves the gradual dissection of gastrointestinal lesions, including early tumors, using high-frequency electric knives and specialized instruments under endoscopic guidance to achieve complete resection of the lesion². Due to the large field of view required during ESD, larger wounds demand more operational space³. If bleeding occurs in such cases, a small operating space may prevent the timely identification and control of the bleeding site³. While transparent caps are used to help expose the surgical field, their effectiveness in large wound areas remains limited⁴. It is generally considered more effective to use a third-hand approach to open the mucosal window for peeling⁵. As a result, numerous ideas and attempts have been made to incorporate auxiliary accessories to enhance the procedure.

Our endoscopic diagnosis and treatment center has been using this ESD technology for many years. For the removal of large gastric mucosal lesions, we use titanium clips and dental floss to assist in ESD, which offers convenience and ease of use. The core principle of dental floss-assisted ESD is to secure the mucosa at the window opening with a titanium clip, which is then connected to a traction wire -- dental floss -- outside the oral cavity⁵. This allows for on-demand pulling of the traction wire during the procedure to help expose and control the field of view, providing significant support to the transparent cap⁶. This method helps prevent issues that may arise from the unintentional continuous expansion caused by the limited field of the transparent cap⁷. As a powerful third hand, dental floss traction expands the operational space, facilitates endoscopic procedures, shortens surgical time, and reduces the risk of side injuries during treatment⁸. This dental floss-assisted traction method has been well-validated in our center. The overall goal of this method is to enhance the safety and efficiency of endoscopic submucosal dissection (ESD) for the removal of large gastric mucosal lesions by providing better control and visualization during the procedure.

Protocol

This study was approved by the Shanghai Civil Aviation Hospital Committee (Ethics Approval No: 2023-06). Informed consent has been obtained from all patients. All ESD procedures were performed by a well-experienced gastroenterologist who had extensive training and practice in performing upper gastrointestinal ESDs. Specifically, the surgeon had more than 10 years of experience performing ESD and had completed over 150 procedures annually.

1. Preoperative preparation

1. Ensure the patient fasts for at least 8 h before surgery and administer intravenous fluids to prevent hypoglycemia and maintain electrolyte balance.
2. Before the surgery, determine the scope, nature, and invasion depth of the lesions by combining intensive endoscopic examination. Adjust the gastroscope settings to the Blue Light Imaging (BLI) mode for optimal imaging. Perform intensive endoscopic examination focusing on observing the microsurface structure (MS) and microvascular structure (MV).
3. Perform tracheal intubation for general anesthesia. Administer proton pump inhibitors 1 h before surgery to prevent bleeding.
   NOTE: Prior to undergoing intensive gastroscopy, it is recommended to take medications that help remove gastric mucus, such as streptomycin protease, and agents that eliminate foam in the stomach, such as simethicone. The Fuji 7000 endoscopy system utilized in our unit is equipped with advanced intelligent dyeing technology, including Blue Light Imaging (BLI) and optical magnification capabilities. The intensive gastroscopy diagnosis adheres to the Magnifying Endoscopy Simple Diagnostic Algorithm for Early Gastric Cancer (MESDA-G).

2. Gastroscopic exploration

1. After administering general tracheal intubation anesthesia, perform gastroscopy on the patient with gastric cavity gas insufflation achieved by using the inflation button.
2. Utilize the suction button to remove fluid and mucus from the stomach and throat.
3. After scrupulously exploring and rinsing the mucosa with water, confirm the location of the tumor under the white light of gastroscopy. Identify the specific location of the lesion based on the detailed gastroscopy examination results.
4. After the exploration, completely aspirate the CO₂ and fluid in the stomach and the fluid and mucus in the esophagus and throat.

3. Scope marking and sufficient exposure of lesions

1. Define the lesion boundary and mark it with an electric knife, maintaining a 5 mm margin from the lesion's edge.
2. Perform multi-point submucosal injection on the outer side of the marked point at the edge of the lesion.
3. Inject a mixture of physiological saline, sodium hyaluronate, methylene blue, and adrenaline beneath the lesion, with a volume of approximately 1 mL each time. The mixture consists of 100 mL of physiological saline, combined with 0.2 mL of methylene blue, 40 mg of sodium hyaluronate, and 1 mg of adrenaline hydrochloride.

4. Endoscopic submucosal dissection of the lesion

1. Use an electric knife to incise the mucosa around the lesion's edge, cutting into the submucosal layer.
2. Use titanium clips and dental floss to assist in traction during surgery as described below.
   1. Open the titanium clip, take a suitable length of dental floss, tie and fix the floss to one foot of the titanium clip, and knot the dental floss at the tail of the titanium clip.
   2. Close the titanium clip and insert it into the biopsy channel. Deploy the clip into the gastric cavity, attach it to the lesion's edge, and gently pull the dental floss to lift the mucosa.
   3. Gently pull the dental floss to pull up the mucosa and expose the boundary of the tumor.
3. Before performing dissection, assess the lifting status of the lesion, and maintain sufficient lifting of the lesion. Fully lift the lesion, carefully separate it along the submucosa, and achieve complete resection. Ensure to completely dissect the mucosal lesion and completely remove the lesion in one go. The settings used for completely lifting the lesion are Mode: Endocut (for cutting), 40 W, effect 3, cutting width 3, cutting interval time 3.
   NOTE: Adequate lifting of the lesion is beneficial for completely removing the lesion without easily damaging the intrinsic muscle layer, reducing the occurrence of complications such as perforation and bleeding.
4. Perform local electrocoagulation hemostasis with hot biopsy forceps during the operation.
5. Completely remove the lesion from the body. If the lesion size is large, extract the specimen using an endoscopic basket. After detaching the specimen, promptly extend and fix it as described in step 7 to prevent tissue ischemia or drying, which could interfere with pathological diagnosis.

5. Closure of the gastric wall defect

1. Perform hot biopsy forceps for local electrocoagulation hemostasis of wounds.
2. Gradually close the wound with metal titanium clips to ensure complete sealing. Use the following settings: Mode: Forced Coagulation (for hemostasis): 40 W, effect 2.

6. Surgical wound check

1. Inspect the wound surface carefully to confirm the absence of active bleeding. Completely aspirate any residual gas and fluid from the stomach cavity.
2. Place a gastric tube in the gastric cavity and withdraw the gastroscope.
3. Administer intravenous antibiotics to prevent infection. Administer a proton pump inhibitor (PPI) to promote wound healing and reduce the occurrence of postoperative bleeding.

7. Specimen management

1. Inspect the specimen visually to confirm its integrity and initial condition.
2. Flatten the specimen fully using tweezers and stainless-steel needles, then secure it onto a fixation plate.
3. Photograph the specimen and document its dimensions.
4. Immerse the specimen entirely in a 4% neutral formalin solution for fixation.

8. Postoperative care and monitoring

1. Monitor closely for any signs of bleeding, including changes in vital signs (heart rate, blood pressure), abdominal pain, the color of gastric tube drainage fluid, vomiting blood, and fecal occult blood.
2. Assess the patient's health status by monitoring abdominal pain and fever.
3. Ensure long-term endoscopic follow-up after surgery. Pathologically, for patients with high-grade intraepithelial neoplasia, perform gastroscopy follow-up 3-6 months after surgery, followed by another examination 12 months later. For patients with low-grade intraepithelial neoplasia, perform gastroscopy re-examination at 12 months post-surgery.

Results

From 2021 to 2024, 10 patients with gastric mucosal lesions underwent ESD assisted by titanium clip and dental floss traction (Table 1). All diagnoses were confirmed by pathological examination, and none required conversion to open surgery. The average age was 69 years. Location of the tumor: four in the esophagus, two in the gastric body, two in the gastric antrum, two in the gastric angle, and one spanning the gastric antrum and angle. Out of the 10 lesions, eight were pathologically classified as high...

Discussion

The prognosis and staging of gastric cancer are related to early diagnosis⁹. Early detection and treatment significantly reduce the mortality rate and improve outcomes for patients¹⁰. This underscores the importance of identifying and effectively managing precancerous lesions in the gastric mucosa¹⁰. Epithelial intraepithelial neoplasia, also known as dysplasia or atypical hyperplasia, belonging to precancerous lesions, is classified according to the...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
adrenaline hydrochloride		Shanghai Hefeng Pharmaceutical Co., Ltd	1 mg per vial
Argon electrode	20132-177	ERBE Elektromedizin GmbH
dental floss		Oral-B Procter and Gamble Ltd.
Digestive endoscopy argon plasma coagulation (APC) knife system	VIO200	ERBE Elektromedizin GmbH
Disposable high-frequency cutting knife,	MK-T-2-195	Micro-Tech (Nanjing) CO, Ltd
Endoscopic therapy device	BL-7000	Fujifilm (China) Investment Co., Ltd
Gastroscopic	EG-760CT	Fujifilm (China) Investment Co., Ltd
Hot biopsy forceps		Nanwei Medical Technology Co., Ltd
methylene blue		Jumpcan Pharmaceutical Group Co., Ltd	2 mL per vial
physiological saline		Chenxin Pharmaceutical Co., Ltd	100 mL per vial
simethicone		Berlin-Chemie AG.Germany	30 mL per vial
sodium hyaluronate		Shanghai Haohai Biotechnology Co., Ltd	20 mg per vial
streptomycin protease		Beijing Tede Pharmaceutical Co., Ltd	20,000 units per vial
titanium clips		Hangzhou Angesi Medical Technology Co., Ltd