Intraoperative Gastroscopy for Tumor Localization in Laparoscopic Surgery for Gastric Adenocarcinoma

Summary

In early gastric cancer, the aim of surgery is to precisely remove the distal stomach including the primary tumor. To do this, accurate localization of the tumor is crucial, especially in totally laparoscopic surgery. This protocol describes a procedure for intraoperative gastroscopy in totally laparoscopic subtotal gastrectomy.

Abstract

Determining resection margins for gastric cancer, which are not exposed to the serosal surface of the stomach, is the most important procedure during totally laparoscopic gastrectomy (TLG). The aim of this protocol is to introduce a procedure for intraoperative gastroscopy, in order to directly mark tumors during TLG for gastric cancer in the middle third of the stomach. Patients who were diagnosed with adenocarcinoma in the middle third of the stomach were enrolled in this case series. Before surgery, additional gastroscopy for tumor localization is not performed. Under general anesthesia, laparoscopic mobilization of the stomach is performed first. After the first portion of the duodenum is mobilized from the pancreas and clamped, the surgeon moves to the other side for the gastroscopic procedure. On the insertion of a gastroscope through the oral cavity into the stomach, 2 - 3 cc of indigo carmine is administered via an endoscopic injector into the gastric muscle layer at the proximal margin of the stomach. The location of stained serosa in the laparoscopic view is used to guide distal subtotal gastrectomy, however, total gastrectomy is performed if the tumor is too close to the esophagogastric junction. A specimen is sampled after distal gastrectomy to confirm sufficient length from resection margin to tumor before reconstruction. In our case series, all patients had tumor-free margins and required no additional resection. There was no morbidity related to the gastroscopic procedure, and the time required for the procedure has gradually decreased to about five minutes. Intraoperative gastroscopy for tumor localization is an accurate and tolerated method for gastric cancer patients undergoing totally laparoscopic distal gastrectomy.

Introduction

Laparoscopic surgery has been become the treatment of choice for early gastric cancer in East Asian countries, including Korea and Japan.¹ The advantage of this surgery has been well demonstrated in several clinical trials for early gastric cancer (EGC).^2-4 Most of the procedures in these trials were accomplished by laparoscopy, but identification of the tumor location, resection of the stomach, including the primary tumor, and reconstruction were performed via minilaparotomy. Therefore, surgery requiring minilaparotomy has been labeled "laparoscopy-assisted gastrectomy."

Recently, however, surgical procedures have evolved to minimize trauma, improving the postoperative quality of life for patients. Since this concept has also been applied in laparoscopic surgery for gastric cancer, some experienced laparoscopic surgeons have tried to avoid minilaparotomy. Totally laparoscopic gastrectomy (TLG) for gastric cancer requires that all procedures are completed using only laparoscopic devices, without requiring an additional minilaparotomy for specimen resection and anastomosis. Since this type of surgery results in less pain and faster recovery relative to open or laparoscopy-assisted surgery, which require laparotomy, more surgeons prefer it.^5,6 However, an obstacle to TLG for gastric cancer is tumor localization without direct visualization or palpation to determine the area of stomach resection.

Tumor absence at the resection margin is very important to achieve success in gastric cancer surgery. If there is tumor involvement at the resection margin during distal gastrectomy for gastric cancer, additional resection is needed to avoid leaving tumor in the remaining stomach. In open and laparoscopy-assisted surgery, the primary tumor can be easily localized by palpation or direct visualization through a temporary gastrostomy. However, because the primary tumor is not easily detected in the laparoscopic view, determining resection margins for EGC in TLG may be difficult.

Several other methods requiring additional preoperative gastroscopy to determine resection margins have been proposed.^7-9 However, additional preoperative gastroscopy can be inconvenient for patients. We introduced a procedure for intraoperative gastroscopy to directly mark tumors during TLG for gastric cancer in the middle third of the stomach.

In this protocol, we applied the laparoscopic surgery for patients with early gastric cancers at the preoperative studies, which are not included in absolute indication for endoscopic submucosal dissection.

Protocol

Ethics Statement: This procedure involving human subjects has been approved by the Institutional Review Board (IRB) at Ajou University Hospital.

1. Preparation for Surgery

1. Allow a soft diet one day before surgery, with nothing by mouth after midnight before the surgery.
   Note: Do not insert a nasogastric tube before and during the surgery. This protocol does not use any tube to deflate the stomach. Instead of that, the intra-gastric gas can be aspirated by laparoscopic puncture needle if the stomach is distended causing limited view for laparoscopic surgery.
2. After placing the patient on the operating table, administer the induction agent (Thiopental Sodium, 100 mg).
3. After intravenous injection of a muscle relaxant (Rocuronium bromide, 1.0 mg/kg), insert the endotracheal tube through the oral cavity.
4. Start the anesthetic gas (Sevoflurane, 2 - 3%) via the endotracheal tube, then monitor the patient for stability during surgery.

2. Surgical Procedure before Intraoperative Gastroscopy

1. Place the patient in reverse Trendelenburg position, and stand at the right side of the patient.
2. Make 10 mm incision at the infraumbilical area, and insert the first trocar into the abdominal cavity.
3. As soon as the trocar is inserted, connect the gas tube for carbon dioxide with the trocar to create a pneumoperitoneum of 15 - 18 mm Hg.
4. Insert a rigid 30° laparoscope through the trocar, and explore the abdominal cavity on a monitor connected with the laparoscopic system.
5. Insert 4 additional trocars (one 12 mm and three 5 mm) as working ports. Insert 12 mm trocar at the right upper side of the umbilicus. Insert other three 5 mm trocars at left upper side of the umbilicus and both upper outer quadrants of the abdomen.
6. Dissect the gastrocolic ligament along the transverse colon toward the inferior pole of the spleen using ultrasonic endoscopic scissors.
7. Ligate the left gastroepiploic artery and vein originating from splenic vessels at the root with a laparoscopic clip and resect them using ultrasonic endoscopic scissors, after exposure of the superior border of the pancreatic tail.
8. Using ultrasonic endoscopic scissors, dissect the peripyloric lymph nodes around the pylorus and the head of the pancreas, and resect the right gastroepiploic vessels at their origin.
9. Before resection of the first portion of the duodenum, clamp the duodenum with a laparoscopic clamp to prevent migration of gas into the small bowel during the gastroscopic procedure (Figure 1).

3. Intraoperative Gastroscopy

1. Move to the left side of the patient's head to perform intraoperative gastroscopy.
2. Insert a gum shield to protect the teeth and gums during intraoperative gastroscopy.
3. Turn the head of the patient to the left side for insertion of the gastroscope.
4. Insert the gastroscope into the stomach carefully through the mouth and the esophagus, to avoid injury to the mucosa of the oral cavity, the esophagus, and the stomach.
5. Insufflate the stomach by injecting gas through the gastroscope to locate the primary lesion.
   Note: Most gastroscopes have a specific button to inject gas into the bowel during the procedure.
6. Approximate the distance between the proximal margin of the tumor and the esophagogastric junction using the scale marked on the gastroscope (Figure 2), and perform total gastrectomy (as described previously) if the distance is too short to salvage the proximal stomach.¹⁰
7. If total gastrectomy is not necessary, insert an endoscopic injector through a small hole of the gastroscope, and inject 2 - 3 cc of indigo carmine into the gastric wall using an endoscopic injector at an area 2 - 3 cm proximal from the tumor margin, avoiding intra- or extraluminal leakage (Figure 3A).
   1. Insert the needle of the injector into the gastric wall obliquely to avoid the perforation of gastric wall by the needle. In addition, inject indigo carmine very slowly to identify intraluminal leakage during injection.
8. After dye injection, aspirate inflation gas through the gastroscope to make the laparoscopic procedure easier.
   Note: Most gastroscopes have a specific button to aspirate inflation gas during the procedure.

4. Procedure after Intraoperative Gastroscopy

1. Return to the right side of the patient after the gastroscopic procedure.
2. In the laparoscopic view, confirm the proximal portion of the tumor by identifying serosal staining by blue dye (Figure 3B).
3. Mark the stained portion to be resected with an endoscopic clip, avoiding involvement of tumor at the resection margin (Figure 4A).
   Note: We recommend performing this procedure within 5 - 10 min after surgery begins, because the dye can sometimes be washed out during subsequent procedures.
4. If the dye cannot be detected in the serosa, immediately re-inject the dye under gastroscopic visualization.

5. Procedure after Intraoperative Gastroscopy

1. Resect the duodenum, and perform other procedures for lymph node dissection according to the Japanese treatment guidelines.¹¹
2. After lymph node dissection, resect the stomach at the proper location at least 3 cm proximal from the tumor margin, guided by the marking clip, using 2 endoscopic staplers.
3. As soon as the distal stomach is resected, insert the specimen into an endoscopic bag and withdraw it from the abdominal cavity through a 2 - 3 cm extension of the infraumbilical trocar site.
4. Send the tissue from the proximal margin to pathology for intraoperative histological evaluation.
5. After confirmation of tumor-free tissue in the proximal portion of the resected stomach, perform an anastomosis between the remaining stomach and the proximal jejunum with intracorporeal linear staplers (Figure 4B).

Results

Of 20 patients who underwent intraoperative gastroscopy, 18 underwent distal subtotal gastrectomy, guided by findings at gastroscopy. However, we performed total gastrectomy on two patients, because the proximal tumor margin was too close to the esophagogastric junction, as determined on intraoperative gastroscopy. The distance from the tumor to the proximal resection margin was 3.5 cm and 2.5 cm in these two patients, respectively (Table 1).

Discussion

In this protocol, we introduced a procedure for intraoperative gastroscopy to accurately and reliably identify tumor location in the middle third of the stomach. We were able to successfully perform distal subtotal gastrectomy based on the findings of intraoperative gastroscopy.

To date, various methods have been applied to identify the location of early gastric cancer in the laparoscopic view. Most common methods used preoperative gastroscopic clipping, and surgeons could detect the location ...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Pentothal Sodium	JW pharmatheutical Co.	644912100	It was used as induction asgent
Rocumeron	Ilsung pharmatheutical Co.	655402960	It was used for general anesthestia as muscle relaxant.
SevoFRAN	Hana pharmatheutical Co.	657801060	It was used as general anesthetics
Endoscopy system	Olympus Corp.	CLV-260	It was used for intraoperative GFS
Laparoscopic surgery system	Striker Endoscopy	1488 HD 3-CHIP	It was a system for laparoscopic surgery
Ultrasonic scissor	Johnson and Johnson Medical Corp.	HAR23	It was used during tissue dissection
Laparoscopic clip	Johnson and Johnson Medical Corp.	ER420	It was used for ligation of the vessels.
Indigo carmine	Korea United Pharma	Carmine	It was injected into the gastric wall
Linear stapler	Johnson and Johnson Medical Corp.	ECHELON FLEX Powered Endopath Stapler	It was used for resection the stomach
Gastroscopic injector	TaeWoong Medical	Cobra injector	I was used for gastroscopic injection of blue dye