ESD treatment of difficult parts of the lesion, usually take repeated submucosal injection, although the subsequent stripping operation provides a limited view of the operation, but the operation time is long, increase the risk of bleeding, perforation. Another simple solution is to adjust the patient's body position according to the direction of gravity, so that the stripping surface to obtain the desired tension, and provide a good operation field of vision, but the patient can choose a limited body position, limit the use of results.
Therefore, how to achieve a good "vision" in the operation, to achieve a safe, accurate cutting and stripping operation method is the key to solve the above problems.
Inspired by the surgical technique, all kinds of endoscope assisted traction technology came into being. According to can be roughly divided into traction for the in vivo and in vitro traction traction force source location. According to the traction device can be divided into metal clip silk combined traction technology, metal clip circle of elastic joint traction technology, S-O metal clip traction technology, magnetic anchor technology etc..
This paper summarizes the advantages and disadvantages of various relevant traction technology, in order to provide reference for clinical choice.
Combined traction technology of metal wire clip
At present, one of the most widely used methods in the esophagus, stomach, duodenum and colon surgery are applied. The technical points are:
1 in vitro ligation of the silk thread in the metal clip between the two clamping arms, through the endoscopic treatment channel, the metal clip is fixed on the cut edge of the lesion (Figure 1a). Light pull the thread to maintain appropriate tension, so that the lesion was fully carried, and then the implementation of a complete stripping. But because of its limited traction direction, it is difficult to apply force to the side of the lesion.
2. Later, scholars have improved on the method, namely in the first metal clip on the side wall of the mucous membrane fixed on another metal clips, the silk thread ligation in the first metal clip from bypass, produced similar to the "block" effect, in order to obtain the anal side direction tension (Fig. 1B).
3 another more direct way is that the second metal clips and the thread is fixed on the side of the mucosa, so that the peel tissue from the side of the tension, see Figure 1c. But this method is insufficient, one is silk itself can only provide directional pull; second is silk itself does not shrink, with the increase of the release face, the thread tension decreases, its role will be decreased or disappeared.
Figure 1 different variants of the metal wire clip combined traction technology (1a. direct wire traction method; 1b. using the "pulley group" effect of the wire traction method; 1c. on the side of the wire traction method)
S-O metal clamp traction technology
In 2009, two Japanese scholars based on the spring, metal clips and nylon ring for the design of another in vivo traction technology, and with the first letter of the two names of the first letter S-O metal clip traction technology. The method consists of a metal clip elastic ring combined with traction of the evolvement, to spring instead of the elastic force ring, trying to obtain greater scalability, to adapt to large, ESD shallow early colon tumor resection (Figure 3).
The spring length of the device is 7 mm, the width is 1.8 mm, the force of 1 G above can make the spring deformation, the maximum extension length is 10 times, the maximum can be 20 G. After the completion of the mucosal stripping, with endoscopic scissors to open the nylon loop, with the specimen removed. Clinical prospective controlled study showed that the operation time of the experimental group, the tumor resection rate and the safety of the experimental group were better than those of the control group.