Natural orifice transluminal endoscopic surgery (NOTES), in which a flexible endoscope is used to perform operations that have traditionally required laparoscopic surgery, has garnered attention as a minimally invasive surgery that does not leave a surgical wound on the body. Among the various forms of NOTES, endoscopic full-thickness resection (EFTR) is an ultraminimally invasive endoscopic surgery that allows for radical resection, which is an extension of endoscopic submucosal dissection and involves full-thickness excision of a tumor of the gastrointestinal tract wall. With further development of the equipment, including full-thickness suture instruments, nonexposed EFTR could be a feasible surgical procedure.
Key points
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Endoscopic full-thickness resection (EFTR) is an ultraminimally invasive endoscopic surgery for radical tumor resection.
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There are 2 types of EFTR: exposed EFTR and nonexposed EFTR.
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Nonexposed EFTR is ideal.
Introduction
EFTR is an ultraminimally invasive procedure in which a flexible endoscope alone is used, and endoscopic submucosal dissection (ESD), is used for full-thickness local excision of a gastrointestinal epithelial malignancy, such as gastric or colon cancer, or a gastrointestinal submucosal tumor, such as a gastrointestinal stromal tumor (GIST).
From improvements in diagnostic performance to therapeutics, flexible endoscopes have progressively been developed; these include development of the various peripheral devices and accessories to the endoscope, including those used to perform polypectomies and endoscopic mucosal resection. With the evolution of incision devices from snares to electrosurgical knives, flexible endoscopes have been used for ESD as an ultraminimally invasive treatment of gastrointestinal tract malignancies and currently as the standard treatment of early-stage gastrointestinal cancer.
Although an excellent therapeutic technique, ESD is still limited to intraluminal treatments, and robust full-thickness closure devices and countertraction devices need to be developed to perform full-thickness excision.
Although full-thickness closure devices have been developed, only the OverStitch Endoscopic Suturing System (Apollo Endosurgery, Austin, Texas) and the Over-The-Scope Clip (Ovesco, Tübingen, Germany) have been commercialized, and the development of full-thickness suturing devices is difficult. The authors have been working toward commercialization of inexpensive suturing devices that have a simple configuration, have highly reliable suturing strength, are simple to operate, and can be used in clinical practice.
Ensuring an appropriate endoscopic surgical field for full-thickness excision and suturing is also a major challenge, but there have been few reports on devices for expanding the field of view. Suturing is impossible if an adequate field of view cannot be achieved. Other than insufflation, there are no means of increasing the field of view of flexible endoscopes in diagnosis and treatment. Thus, if the gastrointestinal tract walls are punctured, the insufflated air flows out from the lumen into the abdominal cavity, and collapse of the gastrointestinal tract makes it difficult to secure the field of view. There are 2 different methods for securing the operative field of view. One is to extend/expand an enclosed cavity by insufflation of CO 2 or a similar gas to increase the field of view for laparoscopy, and another is to mechanically expand the tissue with instruments, such as a surgical retractor, without insufflation. Because the insufflation method is hampered by loss of CO 2 during full-thickness procedures, developing mechanical devices that maintain an adequate field of view is important.
In clinical practice, a pathway of development of NOTES for many of these procedures has been to start with hybrid NOTES procedures, which include collaboration of endoscopists and surgeons.
Laparoscopy and endoscopy cooperative surgery (LECS) was proposed in 2006 ; this superior procedure, which incorporates both safety of laparoscopy and the diagnostic accuracy of endoscopy, has been recognized as safe by both surgeons and endoscopists and has expanded the potential for new minimally invasive surgeries, with various new surgical procedures developed and reported. LECS and hybrid NOTES are similar.
Among NOTES-related procedures, specifically EFTR, it is beneficial to have an endoscopist who is skilled in advanced flexible endoscope treatments, such as ESD. With further development of devices and surgical procedures in the future, an increasing number of gastrointestinal endoscopists may operate in this field. This article describes the authors’ efforts as one of the pioneering EFTR groups to study and address challenges of EFTR, including 2 endoscope techniques to facilitate pure EFTR, prevention of peritoneal contamination, minimization of the risk of tense capnoperitoneum, achieving secure closure with a suturing device that can be operated via a single-channel regular gastroscope, and countertraction devices to maintain visibility during loss of luminal insufflation.
Introduction
EFTR is an ultraminimally invasive procedure in which a flexible endoscope alone is used, and endoscopic submucosal dissection (ESD), is used for full-thickness local excision of a gastrointestinal epithelial malignancy, such as gastric or colon cancer, or a gastrointestinal submucosal tumor, such as a gastrointestinal stromal tumor (GIST).
From improvements in diagnostic performance to therapeutics, flexible endoscopes have progressively been developed; these include development of the various peripheral devices and accessories to the endoscope, including those used to perform polypectomies and endoscopic mucosal resection. With the evolution of incision devices from snares to electrosurgical knives, flexible endoscopes have been used for ESD as an ultraminimally invasive treatment of gastrointestinal tract malignancies and currently as the standard treatment of early-stage gastrointestinal cancer.
Although an excellent therapeutic technique, ESD is still limited to intraluminal treatments, and robust full-thickness closure devices and countertraction devices need to be developed to perform full-thickness excision.
Although full-thickness closure devices have been developed, only the OverStitch Endoscopic Suturing System (Apollo Endosurgery, Austin, Texas) and the Over-The-Scope Clip (Ovesco, Tübingen, Germany) have been commercialized, and the development of full-thickness suturing devices is difficult. The authors have been working toward commercialization of inexpensive suturing devices that have a simple configuration, have highly reliable suturing strength, are simple to operate, and can be used in clinical practice.
Ensuring an appropriate endoscopic surgical field for full-thickness excision and suturing is also a major challenge, but there have been few reports on devices for expanding the field of view. Suturing is impossible if an adequate field of view cannot be achieved. Other than insufflation, there are no means of increasing the field of view of flexible endoscopes in diagnosis and treatment. Thus, if the gastrointestinal tract walls are punctured, the insufflated air flows out from the lumen into the abdominal cavity, and collapse of the gastrointestinal tract makes it difficult to secure the field of view. There are 2 different methods for securing the operative field of view. One is to extend/expand an enclosed cavity by insufflation of CO 2 or a similar gas to increase the field of view for laparoscopy, and another is to mechanically expand the tissue with instruments, such as a surgical retractor, without insufflation. Because the insufflation method is hampered by loss of CO 2 during full-thickness procedures, developing mechanical devices that maintain an adequate field of view is important.
In clinical practice, a pathway of development of NOTES for many of these procedures has been to start with hybrid NOTES procedures, which include collaboration of endoscopists and surgeons.
Laparoscopy and endoscopy cooperative surgery (LECS) was proposed in 2006 ; this superior procedure, which incorporates both safety of laparoscopy and the diagnostic accuracy of endoscopy, has been recognized as safe by both surgeons and endoscopists and has expanded the potential for new minimally invasive surgeries, with various new surgical procedures developed and reported. LECS and hybrid NOTES are similar.
Among NOTES-related procedures, specifically EFTR, it is beneficial to have an endoscopist who is skilled in advanced flexible endoscope treatments, such as ESD. With further development of devices and surgical procedures in the future, an increasing number of gastrointestinal endoscopists may operate in this field. This article describes the authors’ efforts as one of the pioneering EFTR groups to study and address challenges of EFTR, including 2 endoscope techniques to facilitate pure EFTR, prevention of peritoneal contamination, minimization of the risk of tense capnoperitoneum, achieving secure closure with a suturing device that can be operated via a single-channel regular gastroscope, and countertraction devices to maintain visibility during loss of luminal insufflation.
Exposed endoscopic full-thickness resection and nonexposed endoscopic full-thickness resection
EFTR includes what the authors term, exposed EFTR ( Fig. 1 ), in which an endoscope inserted from the mouth or anus is used to intentionally perforate the muscle layer and then perform a full-thickness excision, followed by full-thickness suturing, and also includes what is termed, non-exposed EFTR ( Fig. 2 ), in which the lesion is inverted, and the full-thickness excision is performed only after full-thickness suturing has been performed. In clinical practice, the device development has been in pace with pure EFTR, in which a flexible endoscope alone is used, and the field of view and full-thickness suturing are secured laparoscopically as hybrid-exposed EFTR (so-called LECS).
Nonexposed EFTR involves nonexposed endoscopic wall-inversion surgery (NEWS), a procedure in which hand-sewn sutures are made laparoscopically, followed by full-thickness excision under endoscopy and a combination of laparoscopic and endoscopic approaches for neoplasia using a nonexposure technique, where the mucosa forms a barrier to exposing the peritoneum to luminal contents (see elsewhere in this issue).
Although still in an ex vivo experimental setting, nonexposure EFTR has been achieved as a proof of principle using 2 flexible endoscopes—one inserted through the mouth into the lumen of the stomach and another inserted via an 10-mm umbilical laparoscopic port created by open technique and allowing access to the gastric wall from the peritoneal side (see Fig. 2 A). Using the gastroscope inserted through the mouth, ESD technique is used to perform a circumferential mucosal and submucosal incision around the tumor, leaving the muscular layer intact. The flexible endoscope inserted via the 10-mm umbilical laparoscopic port allows visualization of transmitted light from the orally inserted endoscope as it filters through the circumferential submucosal incision and ring of intact muscularis propria around the lesion. This ring of transmitted light defines the proper resection border on the peritoneal side. Thus, the endoscope on the peritoneal side can grasp the muscularis along this ring using the Twin Grasper (Ovesco Endoscopy) and thus invert the gastric wall ( Fig. 3 A, B ). This inverted full-thickness plication of the stomach is sutured with an endoscope equipped with the double-armed bar suturing system (DBSS), a full-thickness suturing device (see Fig. 3 C). After suturing, the resection is completed from the luminal side by full-thickness excision seromuscular excision with a DualKnife (KD-650L; Olympus, Tokyo, Japan) (see Fig. 3 D).
Related posts:
The New NOTES Expands Interventional Endoscopy
The New NOTES: More “E” and Less “S” Leads to Success!
Submucosal Tunneling Endoscopic Resection (STER) and Other Novel Applications of Submucosal Tunneling in Humans
Endoscopic Full-thickness Resection (EFTR) for Gastrointestinal Subepithelial Tumors
New NOTES Clinical Training and Program Development
Pre-clinical Training for New Notes Procedures
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