Endoscopic surgery of tumors of the gastrointestinal tract

Endoscopic polypectomy. The first endoscopic polypectomy was performed in 1969 by Suneko and Ashida - mechanical shearing with a loop. Later, electroexcision was started. At first, polypectomy was performed only with single polyps on the leg.

Polypectomy is diagnostic and therapeutic. Diagnostic polypectomy is the establishment of a diagnosis after complete removal of the polyp by the method of histological examination.

Indications for diagnostic polypectomy.

1. With all single polyps, if technically possible.
2. With polyposis - removal of 2-3 polyps with the largest size and changed surface.

Indications for therapeutic polypectomy.

It is shown for all single or multiple polyps if the tumor size is more than 5 mm (less than 5 mm - forming polyp) and if a polypectomy can be performed without the risk of causing serious complications

Contraindications to polypectomy.

In addition to general contraindications to the performance of endoscopy, a contraindication to polypectomy is a violation of the coagulation system of the blood.

Methods of polypectomy.

1. Excision (clipping). It is used rarely, because there is a risk of bleeding. It is used to remove small formations when one needs to know their histological structure.
2. Electroexcision is the main method of polyp removal. On the base of the polyp is a loop and tighten it until the polyp's color changes - the vessels clamped with a loop are thrombosed. After 2-3 minutes, tightening the loop, include a coagulator. From the viewpoint of radicality, it is necessary that the base of the neoplasm with the adjacent mucosa be captured in the loop. With this arrangement of the loop due to the extension of the zone of coagulation necrosis towards the mucous membrane, the polyp base and adjacent mucous membrane and even submucosal layer are completely destroyed. However, this technique is not safe, because a real threat of perforation of the organ wall. Cross the leg of the polyp should be started with short impulses (2-3 seconds) with a small diathermic current to achieve a coagulating effect. The longer the coagulation and the broader leg of the polyp, the deeper and larger the area of the mucosal defect. Remove the polyp should be slow. As coagulation of the vessels feeding the polyp, it changes its color - becomes crimson, cyanotic and finally black. If the loop tightens quickly, the polyp is rejected before the vessels completely coagulate and bleeding occurs.
3. Electrocoagulation. It is shown, first, in the presence of small tumors with a base width of up to 5 mm and a height of 2-3 mm, which most often can not be removed with a loop. Secondly, the electrocoagulation method can be used in the case of incomplete loop electroexcision. Thirdly, this method can be widely used to eliminate bleeding that occurs during the electroexcision of neoplasms. The technique consists in bringing the electrothermosonde to the apex of the neoplasm, after which the current is turned on. There is a zone of necrosis, which gradually spreads to the entire neoplasm, as well as to the surrounding mucosa at a distance of 1-2 mm from the base. Before conducting electrocoagulation, a biopsy should be performed in order to know the morphological structure of the neoplasm.
4. Photocoagulation.
5. Drug-induced polypectomy. In the base of the polyp injected 96-degree alcohol, 1-2% acetic acid, etc.

The technique of polypectomy is determined by the type of polyp. Yamada (Yamada) proposed the classification of polyps, which allows you to select the most appropriate technique for removing a polyp of a particular species. According to this classification, there are four main types of polyps:

• Polyp type I - is a formation in the form of a plaque, located on the mucous membrane of the stomach.
• Polyp type II - has the form of a hemisphere. Its consistency is soft. The leg is absent, but when pressed with biopsy forceps, the formation is moderately shifted.
• Polyp type III - round or oval, located on a wide base (broad pedicel). Such polyps sometimes reach large sizes.
• Polyp type IV - has a long leg (sometimes several centimeters), easily shifts in different directions.

Polyps III and IV types prefer polypectomy using a loop. Such polyps coagulate, regardless of the thickness of the leg and the size of the polyp. In those cases when the diameter of the foot does not exceed 4-5 mm, clipping of the polyp with a loop can be performed without electrocoagulation.

It is not easy to remove polyps of types I and II because of the difficulty of hanging the loop and tightening it at the base. To implement this stage of the operation, you have to resort to various techniques: change the size of the loop, the angle of its exit from the device, the method of throwing. When using two-channel endoscopes, it is much easier to locate the loop on the polyp. Biopsy forceps are carried into the open loop, grasp the tip of the polyp and lift it. Then loop through the forceps, as on the guide, lowered aiming on the polyp and tightened. If unsuccessful attempts to capture a small foot of the polyp in the loop, it can be created artificially by injecting a 5-20 ml loop through the base of the polyp through a two-channel 0.25% solution of novocaine.

It is important to note that when tightening the loop and coagulation to the cutting area, the underlying and surrounding tissues are pulled up, which create an elevation (a false leg) with a defect in the center. This elevation can be incorrectly regarded as the result of incomplete removal of the neoplasm and serve as an excuse for a reoperation, which can be complicated by perforation of the organ.

Large polyps (more than 1.5 cm) can be removed in parts: by several grips with a loop electrode, the main part of the polyp is excised, and then its base. With this method, it is possible to obtain a scab whose area does not exceed the area of the base of the polyp. Removing the polyp by parts ensures that the entire thickness of the organ wall, especially the thick one, is captured. This technique can be used for villous tumors and polyps having a short (less than 1 cm) and thick (more than 1 cm) leg in which large vessels pass. Electroexcision in parts allows you to achieve good hemostasis.

With polyps of large sizes, a two-stage poly-pectomy is also used. At the base of the polyp tighten the loop and turn on the current, demarcation develops and a leg is formed, after 3-4 days the polyp is cut off.

Two-stage polypectomy is also used for multiple polyps. With a successful operation and a good state of patients, one can strive for one-step cutting and extraction of all polyps (up to 7-10). But if the patients do not tolerate the introduction of the endoscope, 3-5 polyps can be removed, and after 2-3 days repeat the operation.

Extraction of the polyp. Extraction of a single polyp is mandatory. In polyposis, it is reliable to extract each cut polyp, but for patients unpleasant and not indifferent are the repeated insertion and removal of the endoscope. You can use the collection of polyps in the basket, but it is enough to extract the polyp with the most morphological changes. Extraction of clipped polyps can be performed in various ways: aspiration (sucking the polyp to the endoscope end), grasping them with biopsy forceps, diathermic loop and special tools (trident, four-tooth, basket). The method of extraction depends on the type of endoscope and the set of appropriate instruments. To suppress the peristaltic movements of the walls of the stomach and esophagus, preventing the removal of the drug, you can use glucagon.

After a polypectomy, a control study is performed after 1 week, if there is no epithelization, after another week. Epithelialization occurs in 1 to 3 weeks. For 3 years, the patient is observed once every 6 months. Then 1 time per year for life.

Complications.

1. Bleeding - up to 5% of cases. The causes of bleeding are violations of the technique of electroexcision of tumors (breakage or mechanical cutting of the polyp, insufficient coagulation, prevalence of cutting torque and rapid cutting), the formation of deep and extensive mucosal defects. To reduce the likelihood of bleeding after the polypectomy, the adrenaline solution in the dilution 1: 10000 is injected into the leg of large polyps before resection.
2. Perforation is a rare but terrible complication, for the elimination of which surgical treatment is required. Causes of perforations can be prolonged coagulation, the use of a current of high power and strength, a wide leg of the neoplasm, a violation of the procedure of operation (pressure on the wall of the organ, detachment of the tumor). The probability of perforation increases with increasing pressure on the wall and decreases when 1-2 ml of a 0.9% solution of sodium chloride or other solutions are administered under the polyp base.
3. Burns and necrosis of the mucous membrane outside the polyp zone - in 0.3-1.3% of cases. Occur when the organ walls touch the tip of the polyp, the loop and the bare metal part of the endoscope, or there is liquid at the base of the polyp. In this case, the electric current can spread not only on the base of the polyp, but also on the walls of the organ. To prevent this complication, it is necessary to perform visual control over the course of the operation and to ensure that there is no content in the lumen of the organ.
4. Prolonged non-healing defects of the mucosa. In 95-99% epithelization of coagulation defects occurs within 4 weeks.
5. Relapses of the disease. The frequency of recurrence of the disease and the appearance of new polyps in the stomach is 1.5-9.4%. If the polyp is not completely removed, its residues can be excised during a control endoscopic examination in the immediate postoperative period. Relapses at the site of the removed polyps are associated with abnormalities of the technique performed, and the appearance of new polyps in the distant period is a characteristic feature of polyposis as a disease.

Endoscopic removal of submucosal neoplasms. Endoscopic removal of submucosal tumors is performed with diagnostic and therapeutic purposes. Indications for the operation are determined by the possibility of its technical implementation and safety, as well as the prospect of extraction.

Without the risk of serious complications, the operation is technically feasible under exophytic, dangerous - with intramural and impossible - with endophytic growth of tumors.

Contraindications to endoscopic treatment are:

1. tumors of large sizes (8-10 cm), which are dangerous to remove due to the possibility of complications development and it is difficult to dissect into parts for extraction;
2. endophytic growing tumors of any size;
3. malignant tumors with infiltration of surrounding tissues.

There are two types of endoscopic operations for the removal of submucosal tumors, which differ fundamentally in technique and complexity of surgical techniques.

The first type - endoscopic electroexcision diathermic loop as usual endoscopic polypectomy. This operation is performed with small (up to 2 cm) neoplasms, which, on the basis of visual data, are regarded as polyps. Only histological examination allows to establish non-epithelial character of the removed tumor.

With endoscopic electroexcision, the loop is captured not only by the tumor itself, but also by surrounding tissues. When the loop is tightened, the tumor is squeezed out of its bed and moves up into the loop.

The second type of operation is endoscopic excision (excision) of the tumor from surrounding tissues with a preliminary dissection of the mucosa covering it. It is carried out in several stages:

• hydraulic isolation of the tumor from surrounding tissues;
• dissection of the mucosa covering the tumor;
• excising tumor from surrounding tissues;
• Tumor extraction.

1. At the top of the tumor, up to 5-10 ml of 0.25% solution of novocaine with 1 ml of a 0.1% solution of epinephrine is injected into the submucosal layer with a needle. Thus, a hydraulic preparation of the tumor is produced, which facilitates its excision and prevents bleeding from the bed.
2. A tip of the tumor is dissected by a diathermic electron-knife. The length of the incision should correspond to the diameter of the tumor. As the dissection, the tumor prolapses into the incision in connection with the dilatation of the organ walls by the introduced air.
3. Further actions depend on the depth of the tumor, the shape of its growth, the nature of the relationship with surrounding tissues. The main condition determining the success of an operation is the mobility of the tumor. To determine its mobility, it is necessary to take the tumor with forceps and vigorously stir. If there are no accretions and the location of the tumor is superficial, then after the incision of the mucosa, it significantly protrudes into the lumen of the stomach and must be separated only at the base.

When using a single-channel fibroendoscope, it is easier to do this with a diathermic loop, which is placed on the base of the tumor and gradually tightened. If the tumor is easily removed, then the operation can be completed without using a diathermic current. If an obstacle is felt during the tightening, periodic electroexcitations of the tumor are performed by periodic short (up to 1 s), current pulses. At the same time, it must be pulled upwards towards the end of the endoscope.

When a two-channel fibroendoscope is used with forceps, the top of the tumor is captured by the forceps and pulled upward. Stripping cords between the tumor and its bed are dissected with a diathermic knife or scissors carried along the second channel. In the presence of fusion, a deeply located tumor can be removed only by a two-channel endoscope and it is better to abandon surgery in its absence.

If the tumor is not released from the incision during pull-up and adhesion is not exposed, the electroexcision is continued by the loop. The loop is gradually tightened alternating with the "coagulating" and "cutting" currents, and the forceps are lifted up and the tumor is taken away to the side so that the depth of the cut can be visually checked. It should be borne in mind that the splices are not easily electrocutaneous, and unlike conventional polypectomy, one needs to use a current of great strength, but in short intervals and widely use mechanical extraction of tumors.

4. Tumors are extracted by one of the known methods (special forceps, basket). In this case, the size of the tumor is important. Tumors more than 3 cm in diameter can be removed dangerously, as it is possible to damage the esophagus, so they need to be dissected and extracted in parts. Management of the postoperative period is the same as in endoscopic polypectomy.

Complications.

The risk of complications (perforations and bleeding) in endoscopic excision of submucosal tumors is significantly higher than in normal polypectomy. In this regard, a special place should be taken by measures to prevent them: the correct selection of patients for surgery, determining the depth of the tumor, the availability of special tools, careful compliance with the procedure of the operation.

[1], [2], [3]