Prospective clinical trial of magnetic-anchor-guided endoscopic submucosal dissection for large early gastric cancer (with videos).

BACKGROUND: The treatment of early gastric cancer (EGC) by endoscopic submucosal dissection (ESD) has been rapidly gaining popularity in Japan. However, the procedure needs a high quality of skill. To facilitate complicated ESD by using a single working-channel gastroscope ("one-hand surgery method"), the magnetic-anchor-guided ESD (MAG-ESD) controlled by an extracorporeal electromagnet was reported to be successful in a porcine model. OBJECTIVES: The purpose of this prospective clinical trial was to evaluate the feasibility of MAG-ESD for large EGC located on the gastric body in human beings. DESIGN: Prospective clinical trial at a single center. SETTING: National Cancer Center Hospital, Tokyo, Japan. SUBJECTS: From January 2005 to May 2006, 25 patients with EGC >20 mm in diameter, located in the gastric body, and intestinal-type histology were enrolled. Patients with a cardiac pacemaker, advanced malignancy in other organs, severe cardiac and/or pulmonary diseases, and uncontrolled hypertension and/or diabetes mellitus were excluded from this study. INTERVENTIONS: Similar to a standard ESD, the MAG-ESD procedure was performed with the patient under conscious sedation by intravenous injection of midazolam (3-5 mg) and pentazocine (15 mg). MAIN OUTCOME MEASUREMENTS: Unfavorable events and other intraoperative complications caused by the magnetic anchor or the magnetic force were recorded and evaluated. Two GI endoscopists (T.G., I.O.) assessed whether the magnetic anchor facilitated gastric ESD according to 2 criteria: "supportive" and "not supportive." The en bloc resection rate, complications, total operation time, bleeding, perforation, and recurrence rate were also evaluated. The total operation time was measured from insertion to withdrawal of the endoscope, including the retrieving of the magnetic anchor or anchors. RESULTS: All tumors were resected en bloc, without any perforations or severe uncontrollable bleeding. All magnetic anchors were safely retrieved. Two endoscopists assessed that the MAG system was supportive in 23 patients. None of the patients experienced physiologic and mental abnormalities as a result of long-term magnetic-field exposure. During a median follow-up of 20 months (15-32 months), neither delayed adverse effects nor allergies caused by the stainless steel of the magnetic anchor were observed. CONCLUSIONS: MAG-ESD is a feasible and safe method that allowed an excellent visualization by suitable tissue tension and facilitated gastric ESD in patients with EGC. The system should be miniaturized to make it applicable in daily clinical practice.

A flexible endoscopic surgical system: first report on a conceptual design of the system validated by experiments.

BACKGROUND: Surgery is a standard diagnostic and therapeutic procedure. However, its technical difficulty and invasiveness pose problems that are yet to be solved even by current surgical robots. Flexible endoscopes can access regions deep inside the body with less invasiveness than surgical approaches. Conceptually, this ability can be a solution to some of the surgical problems. METHODS: A flexible (surgical) endoscopic surgical system was developed consisting of an outer and two inner endoscopes introduced through two larger working channels of the outer endoscope. The concept of the system as a surgical instrument was assessed by animal experiments. RESULTS: Gastric mucosa of the swine could be successfully resected using the flexible endoscopic surgical system, thereby showing us the prospect and directions for further development of the system. CONCLUSION: The concept of a flexible endoscopic surgical system is considered to offer some solutions for problems in surgery.

Magnetic anchor for more effective endoscopic mucosal resection.

BACKGROUND: Technical difficulties are involved in endoscopic mucosal resection (EMR) of gastric cancer since it is a "one handed surgery". These difficulties prevent this technique from being indicated for larger lesions, even when it can possibly be performed for patients with such lesions. If microforceps could assist EMR, this procedure would become easier and safer. Since magnetic force can control objects without direct contact, it can be applied to control microforceps internally in assistance with EMR. METHODS: We developed a magnetic anchor consisting of three parts: a magnetic weight with dimensions of 1.0 x 1.0 x 1.5 cm, microforceps and a connecting thread. Endoscopic clips used in hemostasis were used as the microforceps of the magnetic anchor in this study. The magnetic control system consisted of a 0.68 kOe/10 cm/100 A electromagnet, 350 mm in diameter and a circumventing positional frame. The microforceps were inserted into a sheath within the endoscope, and the magnetic weight was secured to the tip of the sheath protruding from the endoscope. The magnetic anchor, along with the endoscope, was inserted through an overtube into the gastric cavity of a swine under general anesthesia. The magnetic anchor was used in a manner similar to that in standard surgery, and EMR was thereby performed. RESULTS: The mucosa to be resected was satisfactorily dragged and stabilized. The magnetic anchor facilitated EMR, regardless of the technical skills of the endoscopist and region of the stomach at which the technique was performed. CONCLUSION: The magnetic anchor is considered to have alleviated some technical problems involved in EMR. It has the potential for making EMR a safer and quicker procedure for the treatment of early gastric cancer, when appropriately indicated.