Gastric endoscopic submucosal dissection assisted by a new traction ...

NEW METHODS: Experimental Endoscopy

Gastric endoscopic submucosal dissection assisted by a new traction method: the clip-band technique. A feasibility study in a porcine model (with video) Adolfo Parra-Blanco, MD, PhD,1,2 David Nicolas, MD, PhD,1 Maria R. Arnau, DVM, PhD,3 Antonio Z. Gimeno-Garcia, MD, PhD,1 Luis Rodrigo, MD, PhD,2 Enrique Quintero, MD, PhD1 Tenerife, Oviedo, Spain

Background: Endoscopic submucosal dissection (ESD) is the standard of care for treating gastric intramucosal neoplasias in Japan. However, it is seldom performed in Western countries, mainly because it is technically very challenging. Several traction methods have been proposed to facilitate submucosal dissection, but they are usually not widely available or are difficult to apply. Objective: Our main aim was to evaluate the feasibility of a new method, the clip-band technique, for improving the visualization of the submucosal layer during ESD. Design: Observational, experimental, feasibility study conducted in a porcine model. Setting: University Hospital of the Canary Islands, Research Animal Laboratory. Patients: Animal study. Interventions: After completion of the circumferential cutting, a clip-band traction system was applied. Main Outcome Measurements: Efficacy and safety of the clip-band technique. Results: Eighteen ESDs performed in live domestic pigs were completed without any serious complications. The mean specimen size was 35.38 ! 12.17 mm, the mean cutting time was 13.06 ! 10.52 minutes, and the mean dissection time was 16.67 ! 9.01 minutes. Limitations: The clip-band technique was not compared with the standard ESD technique. Conclusions: This initial study shows that the clip-band traction technique is feasible and that it permits safe, effective, and relatively inexpensive gastric ESD.

Endoscopic submucosal dissection (ESD) provides en bloc resection more frequently than traditional endoscopic mucosal resection methods.1-4 Piecemeal resection of gastric lesions is a risk factor for lesion recurrence.4 ESD is a complex technique. Despite the advantages of ESD, the risk of perforation is high, and it is technically complex to perform.5-7 Although in Japan ESD can be learned from experts in specialized centers, this method is

only anecdotally performed in Western countries where, therefore, experience with ESD is very limited.5,8 Submucosal dissection after having completed the circumferential cutting is considered the most challenging step of ESD because it is often difficult to obtain a good view of the dissection plane.9,10 If simple, inexpensive, and effective traction methods were available, ESD might become more widely used. We hypothesized that a new

Abbreviation: ESD, endoscopic submucosal dissection.

Department of Gastroenterology (2), Asturias Central University Hospital, Oviedo, Spain, Research Animal Laboratory (3), La Laguna University, Tenerife, Spain.

DISCLOSURE: The authors disclosed no financial relationships relevant to this publication. Copyright © 2011 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 doi:10.1016/j.gie.2011.07.037

Presented at Digestive Disease Week 2010, New Orleans, LA, May 1-5, 2010 (Gastrointest Endosc 2010;71:AB321).

Received February 7, 2011. Accepted July 16, 2011.

Reprint requests: Adolfo Parra-Blanco, MD, PhD, Endoscopy Unit, Hospital Universitario Central de Asturias, Celestino Villamil s/n, 33006 Oviedo, Principado de Asturias, Spain.

Current affiliations: Endoscopy Unit (1), Department of Gastroenterology, University Hospital of the Canary Islands, Tenerife, Spain, Endoscopy Unit,

If you would like to chat with an author of this article, you may contact Dr. Parra-Blanco at [email protected].

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Volume 74, No. 5 : 2011 GASTROINTESTINAL ENDOSCOPY 1137

Gastric endoscopic submucosal dissection via the clip-band technique

Parra-Blanco et al

Take-home Message ●

In this feasibility animal study, the authors show that gastric endoscopic submucosal dissection (ESD) can be performed safely and effectively with a new clip-band traction technique. The superiority of this method compared with conventional ESD, as well as the applicability and results in humans, should be assessed in future studies.

and simple traction method for performing ESD, using 2 clips and a rubber band (the clip-band method), might be a feasible therapeutic option.

METHODS

Figure 1. A, The rubber band is clamped with the clip. B, The clip with the band is retracted into the clip sheath. C, The clip-band system is applied to the inner margin of the resected mucosa. D, The second clip is attached to the normal distal mucosa, after having clamped the band. E, Traction is exerted by the system, and dissection progresses with direct visualization of the submucosal layer.

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Live, female, approximately 30-kg, domestic pigs were used. Details of the preparation and anesthetic procedures have been reported elsewhere.11 Two Western endoscopists participated in this study, both with some previous experience with animal ESD (endoscopist 1: 50 cases, endoscopist 2: 10 cases), and 1 of them (endoscopist 1) also having initial experience with human ESD (7 cases, observation of experts in "40 cases).11 Because this was a feasibility study, we wanted to try the technique in the following different scenarios: (1) hypothetical lesions 2 to 3 cm in diameter in different gastric areas (small resections), (2) large hypothetical lesions approximately 5 to 7 cm in diameter (large resections), (3) subcardial resection, and (4) resection of mucosa with underlying fibrosis, which was secondary to a previous ESD performed 2 weeks earlier. A dedicated endoscope (EG-200HR; Fujinon, Saitama, Japan) and the Erbotom ICC 200 (ERBE Elektromedizin GmbH, Tübingen, Germany) electrosurgical system were used. The technique for ESD was basically similar to previous training in porcine stomachs already reported, using the Flex Knife (KD-630 L; Olympus Medical Systems, Tokyo, Japan), the Insulated-Tip 2 Knife (KD-611L; Olympus Medical Systems), and a solution of 10% glycerin, 0.003% indigo carmine, and 1:300.000 epinephrine for submucosal injection.11 The new technique was applied after having achieved the circumferential cutting. First, a rubber band used for orthodontic treatment (5-6 mm in diameter, and 56.7g to 99.2g strength)(ORMCO Corp, Glendora, Calif) is preloaded in the open prongs of a Resolution clip (Boston Scientific, Natick, Mass) (Fig. 1A). The clip with the loaded band is again pulled back into the sheath (Fig. 1B). Next, it is inserted in the working channel of the endoscope and attached to the proximal inner margin of the resected mucosa (Fig. 1C). Then, the band is clamped again with the second clip, which is pushed toward the normal mucosa distal to the already cut mucosa, where it is attached www.giejournal.org

Parra-Blanco et al


TABLE 1. Technical details of the 18 ESDs performed in a live porcine model Type of resection

Location

Cutting time, min

Dissection time, min

Maximum diameter, mm

Dissection speed, cm2/min

Endoscopist no.

1

Small

LB, GC

8

5

32

1.16

1

2

Small

UB, AW

5

6

33

1.17

1

3

Small

UB, AW

6

6

32

1.09

1

4

Small

LB, LC

24

5

25

0.86

1

5

Subcardial

SC, AW

10

9

22

0.42

1

6

Small

A, GC

9

12

24

0.31

2

7

Small

UB, AW

12

13

37

0.67

1

8

Small

SC, AW

20

15

30

0.35

2

9

Small

UB, GC

7

13

39

0.73

1

10

Small

LB, LC

7

18

35

0.46

1

11

Fibrosis

A, PW

13

19

35

0.48

1

12

Small

UB, GC

10

22

35

0.44

2

13

Small

MB, AW

48

23

22

0.15

2

14

Large

MB, AW

7

27

55

0.58

1

15

Large

A, AW

7

24

70

1.15

1

16

Small

UB, AW

12

20

29

0.31

1

17

Large

LB, GC

6

25

55

1.10

1

18

Small

UB, AW

24

38

32

0.16

2

Case

ESD, Endoscopic submucosal dissection; LB, lower gastric body; GC, greater curvature; UB, upper gastric body; AW, anterior wall; LC, lesser curvature; SC, subcardial; A, antrum; PW, posterior wall; MB, middle gastric body.

(Fig. 1D). Then dissection is performed with the knife, facilitated by the continuous traction exerted by the clipband system (Fig. 1E). The specimens were retrieved by grasping the second clip with a snare and pulling gently; they were then pinned on a cork and measured. The dissection speed was calculated as the area of the specimen divided by the submucosal dissection time. The following variables were recorded: (1) gastric location of the targeted area, (2) time required from the marking until the end of making the circumferential incision (circumferential cutting), (3) dissection time after having applied the clip-band system (submucosal dissection), (4) size of the resected specimen, (5) en bloc versus piecemeal resection, and (6) complications (immediate bleeding, delayed bleeding, perforation). The study was approved by the Ethics Committee of the University Hospital of the Canary Islands.

RESULTS Eighteen resections were performed in a total of 3 pigs (weights: 26.6 kg, 36.2 kg, 29.8 kg). Details of the type of www.giejournal.org

resection, location, specimen size, and procedural times are shown in Table 1. En bloc resection was achieved in all cases except the case involving underlying fibrosis in which the mucosa was resected in 2 pieces. In 2 cases, a second clip-band system had to be applied because the direction of the clips was not adequate (case 1) or additional tension was required in a large resection (case 14). With the application of the second clip-band system, the resections were completed uneventfully. There were no cases of significant bleeding or perforations. Altogether, the mean specimen size was 35.38 ! 12.17 mm, the mean cutting time was 13.06 ! 10.52 minutes, and the mean dissection time was 16.67 ! 9.01 minutes. For the 13 small resections, the mean maximum diameter of the specimens was 31.15 ! 5.1 mm (range 22-39 mm). The mean time from marking until circumferential cutting was 14.77 ! 11.94 minutes, and the mean dissection time was 15.08 ! 9.37 minutes. The application of the clip-band system never took more than 3 minutes. The subcardial resection was the only one that had to be performed in the retroflexed position. The subcardial resection and the 3 large resections, and to a Volume 74, No. 5 : 2011 GASTROINTESTINAL ENDOSCOPY 1139


Figure 2. Large endoscopic submucosal dissection (55 mm maximum diameter) in the greater curvature. A, View after completion of the circumferential cutting and application of the first clip. B, After having attached the second clip to the normal mucosa distal to the resection margin, traction is exerted and the submucosal layer can be easily recognized.

lesser extent the resection in the fibrosis-associated case, were accomplished rather easily (Table 1; Video 1, available online at www.giejournal.org; Fig. 2).

DISCUSSION Submucosal dissection is the most difficult step of ESD, and self-completion by beginners is hampered especially at this stage.9 To facilitate the dissection, several methods have been proposed for use in the stomach and the colon: using longer-lasting solutions in the submucosa,10 transparent hoods,10 or traction methods.12-22 The method proposed by Sakurazawa et al21 has some similarities to ours. However, in their study, the second clip was applied not distally to the lesion, but on the opposite gastric wall. The method proposed by Matsumoto et al22 in a case report also has similarities to ours, but they applied the clip, which could not be reopened, on the distal margin of the lesion. Compared with most previous traction methods, the clipband method is widely available, very easy to prepare, and rather inexpensive (the price for the 2 clips is approximately $200, and the price of a package of 100 bands is about $5). The idea for our method came after learning about the S-O 1140 GASTROINTESTINAL ENDOSCOPY Volume 74, No. 5 : 2011

Parra-Blanco et al

clip traction method reported by Sakamoto et al.18 The first author of our study was undergoing orthodontic treatment at that time, which included use of the rubber bands. We tried several sizes of bands at the beginning of the animal study and found that the 6-mm bands are generally the most convenient, especially if thin (56.7 g strength), because they can be easily pushed out of the clip sheath. In our study using the clip-band system, procedure times were remarkably short, and this might be a potential advantage of this method. However, the lack of a control group compromises meaningful interpretation of the study findings. In the future, well-designed comparative studies should clarify this issue. One potential problem with this method is that if the clips are incorrectly placed, traction might be applied in an incorrect direction, and, therefore, the safety and effectiveness of ESD might be hampered. However, it is easy to detach the second clip by using a snare if required. Then, a new clip can be inserted to clamp the band and place it in the correct position. Alternatively, a second clip-band system can be applied to modify the traction exerted. To apply the second clip to the most adequate area, we recommend pushing the clip=s sheath, instead of the endoscope, distally to the lesion, so that the desired area can be selected while the lesion is observed. We suggest that the second clip be applied 1 to 2 cm distal to the circumferential cutting line, in an imaginary line in along the long axis of the stomach passing through the middle of the lesion. ESDs could be performed en face (whereas most Japanese experts favor the use of the retroflexed position) and with almost no trimming (initial dissection after having completed the circumferential cutting), advantages that we believe to be especially useful for beginners. Another potential advantage of this method is that the clips attached to the specimen facilitate the orientation for histopathological examination. Not only small and theoretically easy resections were performed in this study. We also performed large resections, a subcardial resection, and a resection involving marked fibrosis. This clip-band method was only studied in the context of a feasibility study; thus, future animal and human studies should clarify the effectiveness of this new method for achieving gastric ESD easily, even in difficult situations. This is the first description of a traction method for ESD from a non-Asian country, and traction methods are believed to play an important role in the development of ESD in Western countries.

CONCLUSION In this feasibility animal study, we have shown that gastric ESD can be performed safely and effectively with a new clip-band traction technique. The superiority of this method compared with conventional ESD, as well as the applicability and results in humans, should be assessed in future studies. www.giejournal.org

Parra-Blanco et al


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