TECHNIQUES AND PITFALLS OF ENDOSCOPIC SUBMUCOSAL DISSECTION FOR COLORECTAL TUMORS

Endoscopic submucosal dissection (ESD) for colorectal tumors is steadily being developed. Safety and standardization of ESD for colorectal tumors have not been yet established because of the technical difficulties and the unsuitable anatomical characteristics of the colon and rectum. The authors mainly use a Flex knife for mucosal incision and a Hook knife for submucosal dissection to perform ESD safely. Skillful colonoscopic control, selection of scope, distal attachment tip hood, adequate high‐frequency generator and correct approach strategy should all be considered for safe performance of ESD. However, the incidence of indicative lesions is rare because the majority of colorectal tumors are adenomatous large laterally spreading tumors, which can be cured by intentional endoscopic piecemeal resection. At present, ESD for colorectal tumors should be performed only at central facilities that have expert colonoscopists. With the development of new devices and associated techniques, technical standardization of ESD for colorectal tumors is expected in the near future.     

ENDOSCOPIC SUBMUCOSAL DISSECTION WITH SHEATH‐ASSISTED COUNTER TRACTION FOR EARLY GASTRIC CANCERS

Aim: Endoscopic submucosal dissection (ESD) is associated with frequent complications, such as bleeding and perforation. The procedure is technically difficult, requires considerable skill and is longer than conventional endoscopic mucosal resection (EMR). Thus, non‐invasive tools and methods are needed to facilitate direct visualization of the submucosal layer during ESD. Methods: An insulation‐tipped (IT) knife was inserted into one channel, and a conventional injection sheath was inserted to the other channel of a double‐channel fiberscope. The submucosal layer was lifted via a circumferential incision using the conventional injection sheath for visualizing cutting lines, and the submucosal layer under the lesion was directly dissected from the underlying muscularis propria. Results: Sheath‐assisted traction resulted in successful ESD with en bloc resection in all 25 patients. Hemostasis and manipulation of blood vessels were uncomplicated and dissection was completed safely, without either bleeding or perforation. The movement of the sheath was not suppressed while lifting the submucosal layer and the IT knife could be moved freely, which allowed submucosal dissection independently of the sheath movement. Conclusion: Sheath‐assisted traction ESD, using simple materials and methods, has several advantages over other standard traction methods. Our procedure is straightforward, safe, non‐invasive, cost‐effective and uses readily available instruments to enhance visualization of cutting lines.     

ENDOSCOPIC SUBMUCOSAL DISSECTION FOR EARLY GASTRIC CANCER: TECHNICAL FEASIBILITY,OPERATION TIME AND COMPLICATIONS FROM A LARGE CONSECUTIVE SERIES

Background: Endoscopic mucosal resection (EMR) is a recognized treatment for early gastric cancer (EGC). One‐piece resection is considered to be a gold standard of EMR, as it provides accurate histological assessment and reduces the risk of local recurrence. Endoscopic submucosal dissection (ESD) is a new technique developed to obtain one‐piece resection even for large and ulcerative lesions. The present study aims to identify the technical feasibility, operation time and complications from a large consecutive series. Methods: We reviewed all patients with EGC who underwent ESD using the IT knife at National Cancer Center Hospital in the period between January 2000 and December 2003. Results: During the study period of 4 years we identified a total of 1033 EGC lesions in 945 consecutive patients who underwent ESD using the IT knife. We found a one‐piece resection rate (OPRR) of 98% (1008/1033). Our OPRR with tumor‐free margins was 93% (957/1033). On subgroup analysis it was found to be 86% (271/314) among large lesions (≥ 21 mm) and 89% (216/243) among ulcerative lesions. The overall non‐evaluable resection rate was 1.8% (19/1033). The median operation time was 60 min (range; 10–540 min). Evidence of immediate bleeding was found in 7%. Delayed bleeding after ESD was seen in 6% and perforation in 4% of the cases. All cases with complications except one were successfully treated by endoscopic treatment. Conclusion: The present study shows the technical feasibility of ESD, which provides one‐piece resections even in large and ulcerative EGC.     

CLINICAL RESULTS OF ENDOSCOPIC HEMOSTASIS USING A SHORT TRANSPARENT HOOD AND SHORT HEMOCLIPS FOR NON‐VARICEAL UPPER GASTROINTESTINAL BLEEDING

Aim: Endoscopic hemostasis using hemoclips is useful, but there are technical difficulties because the angle of the approach is tangential. A transparent hood facilitates the observation and treatment of these lesions, and a shorter hood provides a wider visible field. Endoscopic hemoclipping of hard lesions with hemoclips of the conventional size does not reliably result in sustained hemostasis because the clips slip. Short clips, however, can be easily clamped on protruded visible vessels without slip. The aim of the present study was to evaluate the efficacy of endoscopic hemostasis with a short transparent hood and short clips. Methods: Subjects were 198 patients with 214 lesions of non‐variceal upper gastrointestinal bleeding at Keio University Hospital. We used a video endoscope with a short transparent hood attached to its distal tip and carried out hemostasis using short hemoclips. Results: The short transparent hood provided a good visual field. If the lesions were in the tangential, the short hood made it possible to observe them in the frontal view and made clip hemostasis much easier. The short clip could be securely clamped against protruded visible vessels. Of 214 lesion, 211 (98.6%) had temporal hemostasis. Rebleeding occurred in 13 of 211 lesions (6.2%), and 205 of 214 lesions (95.8%) had permanent hemostasis. Nine cases were endoscopically difficult. Conclusion: Endoscopic hemostasis with a short transparent hood and short clips is useful for non‐variceal upper gastrointestinal bleeding.     

ENDOSCOPIC PROCEDURE UNDER IRRIGATION

Background: Endoscopic therapy is often difficult to achieve particularly when the field of view of the lesion is poor due to contamination of mucus and blood. We developed five different types of end hoods that facilitate endoscopic procedures by simultaneously allowing various treatments and irrigation of the site. Methods: The end‐hood pieces were fabricated by drilling a side hole in the cap portion of conventional transparent hoods, then the irrigation tube was glued to the exterior surface of the hole. The fabricated transparent hood was placed at the tip of the endoscope. Results: Types 1 and 2 were useful for upper‐gastrointestinal (GI) hemorrhage, type 3 for lower‐GI hemorrhage, type 4 for endoscopic submucosal dissection and type 5 for endoscopic mucosal resection. Conclusions: With this method, endoscopic procedure is easy and economical, as therapeutic procedures can be performed under irrigation using a conventional endoscopy.     

ENDOSCOPIC SUBMUCOSAL DISSECTION FOR SUPERFICIAL DUODENAL NEOPLASMS

Endoscopic submucosal dissection (ESD) has emerged as a novel technique for achieving en bloc resection for superficial neoplasms limited to the mucosa. ESD was originally developed in Japan as a method of endoscopic resection of superficial gastric cancers. In our hospital, ESD has been used concurrently in other parts of the gastrointestinal tract, including the esophagus and colorectum from the beginning of its development. However, ESD in the duodenum is considered more challenging than other parts. From August 2005 to March 2008, a total of 15 superficial duodenal neoplastic lesions in 14 patients were treated with endoscopic resection. Of these, nine underwent ESD. We report our experience with duodenal ESD with a combination of ST hood and hook knife.     

USE OF SHORT NEEDLE KNIFE FOR ESOPHAGEAL ENDOSCOPIC SUBMUCOSAL DISSECTION

Background: The emergence of endoscopic submucosal dissection (ESD) has enabled en bloc resection of lesions, which were conventionally difficult. However, ESD has problems of technical difficulty and high incidence of complications. In order to improve the procedure of marking and submucosal dissection in the esophagus, we modified and adjusted the standard needle knife to a short needle knife having a tip portion with a projection length of 1.5 mm. Methods: We treated 20 esophageal lesions with ESD using the short needle knife. We marked around the lesion with the short needle knife and performed mucosal incision of the entire circumference with a needle knife and an IT knife, then dissected the submucosal layer with the short needle knife. A Hook knife was also used in situations where muscular layers were located in the front‐view Results: Complete en bloc resection was performed in all 20 cases. The diameter of lesions ranged from 3 to 65 mm (median, 20 mm), and that of resected specimens ranged from 28 to 90 mm (median, 47 mm). Submucosal dissection was completed with the short needle knife alone in 13 cases in 20 (65%), and in seven cases (35%), in combination with so‐called Hook knife. The procedure was complicated in one patient with mediastinal emphysema. Conclusions: The short needle knife proved to be useful and safe in clear marking and submucosal dissection of esophageal lesions. It allows greater flexibility in the angle of insertion, and enables more effective and safer procedures because its full length can be inserted into the submucosa and fixed.     

Prospect of Endoscopic Mucosal Resection for Early Gastric Cancer: Our Devices in Insulated‐Tip Electrosurgical Knife Method

In Kobe University Hospital, a new method for endoscopic mucosal resection (EMR) using insulated‐tip electrosurgical knife (IT‐EMR) for early gastric cancer (EGC) was introduced from November 2001. To achieve an effective and safe IT‐EMR procedure, we use a high‐frequency surgical unit for cutting and coagulation (ERBOTOM ICC 200) with automatically controlled cutting mode (ENDOCUT). In this study, we show not only our results of IT‐EMR for EGC in comparison with those of the conventional strip biopsy method, but also the optimal conditions for the apparatus of a high‐frequency surgical unit to prevent complications such as bleeding and perforation.     

Newly Developed Endoscopic Resection Technique for Colorectal Tumors

We applied a newly developed endoscopic resection technique for a rectal mucosal cancer of 4.2 cm. This method resulted in a curable treatment and provided precise information for histological examinations. This technique, using IT‐knife, may involve the risk of bleeding and perforation compared with conventional methods. Further improvements are needed to make this technique safer and more reliable for a standard endoscopic method for large colorectal tumors.     

Endoscopic treatment of upper GI hemorrhage with a novel irrigating hood attached to the endoscope

BACKGROUND: Despite advances in endoscopic treatment methods for upper GI hemorrhage, hemostasis is often difficult to achieve, particularly when the endoscopic view at the site of hemorrhage is poor because of the presence of mucus and blood. The investigators developed an end hood that facilitates endoscopic hemostatic procedures while simultaneously allowing irrigation of the bleeding site. The usefulness of this end hood for treatment of upper GI hemorrhage, excluding hemorrhage from varices, was evaluated. METHODS: The end-hood piece was fabricated by drilling a side hole in the cap portion of a conventional transparent hood. An irrigation tube then was glued to the exterior surface of the hole. The fabricated transparent hood was placed on the tip of an endoscope. With the hood piece in place, hemoclip placement and other endoscopic hemostatic procedures were performed in 15 patients with nonvariceal upper GI hemorrhage. RESULTS: Hemostasis was successfully achieved in all cases. In all cases of active hemorrhage, hemostatic treatment was enhanced by simultaneous irrigation beneath the hood. The median time required for the hemostatic procedure with the attached hood was 4.8 minutes. CONCLUSION: The end-hood irrigation device and technique facilitate endoscopic hemostatic treatment of nonvariceal upper GI hemorrhage.     

Use of Sato's curved laryngoscope and an insulated‐tip knife for endoscopic incisional therapy of esophageal web

We experienced two cases of esophageal web accompanying severe stricture that were treated by endoscopic incisions with an insulated‐tip knife (IT‐knife). With attention paid to the mucosa at the stricture, the lesion was incised with an IT‐knife without complications. Sato's curved laryngoscope was used even in cervical esophageal lesions and an excellent field was secured.     

RISK MANAGEMENT IN ENDOSCOPIC SUBMUCOSAL DISSECTION USING NEEDLE KNIFE IN KOREA

The needle knife is used for mucosal incision during endoscopic mucosal resection (EMR). The first author has used the needle knife for EMR since 1996 to overcome several limitations. Conventional EMR is not able to be used to remove tumors >15 mm. Excessive burning effect on the margin during strip biopsy leads to misdiagnosis during evaluation of resection margins. Relatively larger specimens could be resected and resection margins evaluated effectively with EMR with needle knife. Nowadays the needle knife is used to perform endoscopic submucosal dissection (ESD) from mucosal incision to submucosal dissection. The advantages of needle knife are as follows: (i) the lumen of the stomach can be kept clear during the whole procedure because of less burning effect; (ii) the procedure time for ESD is short because the needle knife has a very thin body, enabling the mucosal and submucosal layer to be cut quickly; and (iii) the needle knife can provide cutting action with the tip. In contrast, the needle knife has a high potential to cause perforation during incision and dissection. Only experts can use the needle knife safely. The perforated site can be closed endoscopically using hemoclips. To prevent perforation the needle knife should be kept parallel to the gastric wall during dissection. In conclusion, the needle knife has many advantages as well as a higher risk of perforation. However, the success rate for ESD using the needle knife increases with sufficient experience.     

ENDOSCOPIC MUCOSAL RESECTION FOR EARLY GASTRIC CANCER: A NEW TECHNIQUE USING A SLIT‐HOOD and HOOK KNIFE

We report a successful application of a new submucosal dissection method for EMR using an endoscope equipped with a slit‐hood and hook knife. The mucosal lesion is separated from the submucosal layer with the aid the hood and the submucosal fibers are cut with the hook knife introduced through the slit, allowing an easy and safe dissection with good visualization of the tissue. Twenty‐seven patients with early gastric cancer underwent EMR using a slit‐hood and hook knife. Tumors were completely resected in 10 cases, and perforation of the stomach occurred in one case. The hook knife cuts as it is pulled back into the hood, helping to prevent perforation.     

Endoscopic hemostatic treatment under irrigation for upper-GI hemorrhage: a comparison of one third and total circumference transparent end hoods

BACKGROUND: Endoscopic hemostasis for upper-GI hemorrhage often is difficult to achieve if the view of the bleeding lesion is poor because of the presence of mucus, blood, and clots. An end hood that facilitates endoscopic hemostatic procedures while simultaneously allowing irrigation of the bleeding site was designed by us. Based on this design, a one-third partial irrigating end hood was developed, and its usefulness for treatment of non-variceal hemorrhage was evaluated. METHODS: The end hood was fabricated by drilling a side hole in the cap portion of a transparent end hood. An irrigation tube was glued to the exterior surface over the hole. A "total" (type 1) and a "one-third partial" (type 2) transparent end hood were fabricated. These differ with respect to the proportion of the endoscope circumference that is hooded by the device. The fabricated transparent end hood was placed on the tip of a standard endoscope. With the end hood in place, endoscopic hemostatic treatment under irrigation was performed in 35 patients (type 1 end hood, 18; type 2, 17) with non-variceal upper-GI hemorrhage. OBSERVATIONS: Hemostatic treatment was enhanced by simultaneous irrigation beneath the end hood, and hemostasis was successfully achieved in 34 of 35 cases. The time required to achieve hemostasis was significantly shorter in the type 2 group than the type 1 group (median 11.8 vs. 16.9 minutes; p < 0.05). CONCLUSIONS: The end hood was extremely useful for endoscopic hemostatic treatment under irrigation. The "one-third partial" end hood is superior to the total end hood in terms of duration of time required to achieve hemostasis.     

ENDOSCOPIC SUBMUCOSAL DISSECTION FOR RECURRENT GASTRIC TUMORS

Endoscopic resection has been accepted as the standard treatment for intramucosal gastric tumors of differentiated type. However, the indication was limited to small tumors to achieve en bloc resection and prevent local recurrence in cases of conventional endoscopic mucosal resection (EMR) such as the strip biopsy and the cap technique. To avoid multi‐fragmental resection, we have developed endoscopic submucosal dissection (ESD) as a new endoscopic resection technique. ESD is a remarkable technique, because we make it possible to remove the lesions en bloc regardless of size, shape, coexisting ulcer, and location. However, it is difficult or impossible to resect recurrent tumors en bloc in conventional EMR owing to hard fibrosis, and some patients need laparotomy. Using ESD, we can dissect the submucosal layer as we directly look at the submucosa, and remove the lesion safely and reliably even in cases of hard fibrosis. The key to treatment of recurrent tumors in ESD are as follows: (i) using enough submucosal injection solution (we use a mixture of Glyceol and 1% 1900 kDa hyaluronic acid preparation); (ii) incising the mucosa without fibrosis; (iii) understanding characteristics of various cutting devices, and changing other devices in difficult situations. In these ways we can remove the majority of the recurrent tumors en bloc. Hence, we consider that ESD is a very effective treatment which achieves excellent en bloc and complete resection rates and enables patients with intramucosal gastric tumors to a recurrent‐free survival even in recurrent tumors.     

Randomized controlled trial comparing submucosal endoscopy with mucosal resection and endoscopic submucosal dissection in the esophagus and stomach: Animal study

Background and Aim

In Western countries, endoscopic submucosal dissection (ESD) has not prevailed as a result of training problems and a target patient population. We have previously reported a hybrid ESD technique, submucosal endoscopy with mucosal resection (SEMR), in which the submucosal dissection is carried out chiefly by blunt balloon dissection. We have also reported successful application in the porcine colon. In the present study, we compared the safety and efficacy of SEMR with ESD in the porcine esophagus and stomach.

Methods

SEMR and ESD were carried out in eight domestic pigs under general anesthesia. Resection sites were marked by circumferential coagulation. After circumferential ESD knife mucosal incision, submucosal fluid cushion (SFC) was created. In the SEMR group, the balloon catheter was inserted deep into the SFC. The balloon was then inflated and pulled back toward the endoscope tip repeatedly, altering the direction, to disrupt the submucosa. Residual strands were cut with an IT‐knife. En bloc resection rates, procedure times, complications and dissection difficulty scales (DDS) were recorded prospectively. DDS were rated using a visual analog scale.

Results

Thirty‐two resections (8 SEMR/8 ESD in the esophagus; 8 SEMR/8 ESD in the stomach) were done with no major adverse events. There was no statistical difference between the two techniques in either location in the above categories measured.

Conclusions

SEMR and traditional ESD are comparable techniques in safety and effectiveness when carried out in the esophagus and stomach. SEMR may serve as a more appealing technical option for endoscopists who are unable to sustain a traditional ESD practice volume.     

RISK MANAGEMENT TO PREVENT PERFORATION DURING ENDOSCOPIC SUBMUCOSAL DISSECTION

En bloc resection is beneficial for accurate histological assessment of resected specimens of endoscopic mucosal resection. Conventional endoscopic mucosal resection is simple and convenient but with this procedure the size of specimen obtained from one‐piece resection is very limited. Endoscopic submucosal dissection (ESD) using IT knife, Hook knife, Flex knife and so on has already been reported and it is useful to some expert endoscopists, but sometimes difficult for general endoscopists to use safely. The drawback of ESD is that it is difficult and is consequently associated with a higher rate of perforation, which may reach up to 2–6% . In addition, ESD requires advanced endoscopic techniques. Further improvement of devices and techniques is expected to be developed to prevent perforation for ESD procedure.     

MANAGEMENT OF BLEEDING CONCERNING ENDOSCOPIC SUBMUCOSAL DISSECTION WITH THE FLEX KNIFE FOR STOMACH NEOPLASM

Management of bleeding is crucial for a successful endoscopic submucosal dissection (ESD) with the Flex knife for a stomach neoplasm. Medical approaches to suppress gastric acid secretion and keep systolic blood pressure at the level of < 150 mmHg during ESD are tried to lessen bleeding. But, major concerns for bleeding are whether the blood vessels are cut off or not and endoscopic surgeons have to avoid blind application of devices for ESD as much as possible. Even in the situations where blind application for non‐visible vessels in the submucosa is not preventable such as in the steps of marking, submucosal injection, mucosal incision, and snaring, the efforts to lessen bleeding are necessary. When non‐bleeding visible vessels are noticed, ‘prebleeding coagulation’ with appropriate devices is important. Even if unexpected bleeding occurs, it is also controllable using appropriate devices according to the type of bleeding. All endscopists who perform ESD should also be experts in management of bleeding.     

Endoscopic submucosal dissection for superficial esophageal neoplasms using the stag beetle knife

Endoscopic submucosal dissection (ESD) is an accepted standard treatment for early gastric cancer but is not widely used in the esophagus because of technical difficulties. To increase the safety of esophageal ESD, we used a scissors‐type device called the stag beetle (SB) knife. The aim of this study was to determine the efficacy and safety of ESD using the SB knife. We performed a single‐center retrospective, uncontrolled trial. A total of 38 lesions were excised by ESD from 35 consecutive patients who were retrospectively divided into the following two groups according to the type of knife used to perform ESD: the hook knife (hook group) was used in 20 patients (21 lesions), and the SB knife (SB group) was used in 15 patients (17 lesions). We evaluated and compared the operative time, lesion size, en bloc resection rate, pathological margins free rate, and complication rate in both groups. The operative time was shorter in the SB group (median 70.0 minutes [interquartile range, 47.5–87.0]) than in the hook group (92.0 minutes [interquartile range, 63.0–114.0]) (P = 0.019), and the rate of complications in the SB group was 0% compared with 45.0% in the hook group (P = 0.004). However, the lesion size, en bloc resection rate, and pathological margins free rate did not differ significantly between the two groups. In conclusion, ESD using the SB knife was safer than that using a conventional knife for superficial esophageal neoplasms.     

New role of the dual knife for precut papillotomy in difficult bile duct cannulation

The dual knife is usually used for endoscopic submucosal dissection (ESD). To date, however, there have been no clinical trials of the safety and effectiveness of precut papillotomy using the dual knife for biliary access in patients failing conventional endoscopic retrograde cholangiopancreatography (ERCP) cannulation. We herein report 18 patients who underwent precut papillotomy with the dual knife. All had intact papilla, and had failed deep cannulation of the bile ducts. After successful biliary cannulation and standard endoscopic sphincterotomy, if necessary, stone removal or plastic or metal stent insertion was attempted. Selective bile‐duct cannulation was achieved in all 18 patients (100%), at an average time of 4.2 min (range, 3–6 min). Of these 18 patients, six had malignant bile duct obstruction and 12 had common bile duct stones. One patient developed post‐ERCP pancreatitis, which resolved after conservative management. There were no deaths related to the procedure.