Superior mesenteric artery (a. mesenterica superior). Acute disorders of the mesenteric circulation. Treatment How big should the superior mesenteric artery be?

1. Superior mesenteric artery, a mesenteric superior. Unpaired branch of the abdominal aorta. It starts about 1 cm below the celiac trunk, first lies behind the pancreas, then passes in front of the uncinate process. Its branches continue into the mesentery of the small and transverse colon. Rice. A, B.

2. Inferior pancreatoduodenal artery pancreaticoduodenalis inferior. It departs at the level of the upper edge of the horizontal part of the duodenum. Its branches lie in front and behind the head of the pancreas. Rice. A. 2a Anterior branch, ramus anterior. Anastomoses with the anterior superior pancreatoduodenal artery. Rice. AT.

3. Jejunal arteries, aajejunales. Goes to the jejunum in her mesentery. Rice. BUT.

4. Ileal arteries, aa ileales. They approach the ileum between the two sheets of its mesentery. Rice. BUT.

5. Ileocolic artery, a. ileocolica. In the mesentery of the small intestine goes down and to the right to the iliocecal angle. Rice. BUT.

6. Colon branch, ramus colicus. Goes to the ascending colon. Anastomoses with the right colonic artery. Rice. BUT.

7. Anterior caecal artery, a. caecalis (cecalis) anterior. In the caecal fold, it approaches the anterior surface of the caecum. Rice. BUT.

8. Posterior caecal artery, a. caecalis (cecalis) posterior. Heads behind the terminal ileum to the posterior surface of the caecum. Rice. BUT.

9. Artery of the appendix, a. appendicularis. It crosses behind the ileum and lies along the free edge of the mesentery of the appendix. The place of origin of the artery is unstable, it can be double. Rice. A. 9a Ileal branch, ramus ile: alis. It goes to the ileum and anastomoses with one of the small intestinal arteries. Rice. BUT.

10. Right colonic artery, a. colic dextra. Anastomoses with the ascending branch of the ileocolic and middle colonic arteries. Rice. A. 10a Artery of the right flexure of the colon, aflexura dextra. Rice. BUT.

11. Middle colonic artery, a. colica media. It is located in the mesentery of the transverse colon. Rice. A. Pa Regional colonic artery, a. marginalis coli[]. Anastomosis of the left colic and sigmoid arteries. Rice. B.

12. Inferior mesenteric artery, and tesenterica inferior. Departs from the abdominal part of the aorta at the level of L3 - L4. Heads to the left and supplies the left third of the transverse colon, descending, sigmoid colon, as well as most of the rectum. Rice. B. 12a Ascending [intermesenteric] artery, a ascendeus. Anastomoses with the left colonic and middle colonic arteries. Rice. A, B.

13. Left colonic artery, a. colic sinistra. Retroperitoneally goes to the descending colon. Rice. B.

14. Sigmoid-intestinal arteries, aa. sigmoideae. Goes obliquely down to the wall of the sigmoid colon. Rice. B.

15. Superior rectal artery, a. rectalis superior. Behind the rectum, it enters the small pelvis, where it is divided into right and left branches, which, perforating the muscle layer, supply the intestinal mucosa with blood to the anal flaps. Rice. B.

16. Middle adrenal artery, and suprarenalis (adrenalis) media. It departs from the abdominal part of the aorta and supplies the adrenal gland with blood. Rice. AT.

17. Renal artery, a. renalis. It starts from the aorta at the level of L 1 and divides into several branches that go to the hilum of the kidney. Rice. C, D. 17a Capsular arteries, aaxapsulares (perirenales). Rice. AT.

18. Inferior adrenal artery, a. suprarenalis inferior. Participates in the blood supply to the adrenal gland. Rice. AT.

19. Anterior branch, ramus anterior. Blood supply to the upper, anterior and lower segments of the kidney. Rice. V, G.

20. Artery of the upper segment, a. segment superioris. Spreads to the posterior surface of the kidney. Rice. AT.

21. Artery of the upper anterior segment, a. segmenti anterioris superioris. Rice. AT.

22. Artery of the lower anterior segment, a segmenti anterioris inferioris. Branch to the anteroinferior segment of the kidney. Rice. AT.

23. Artery of the lower segment, a. segmenti inferioris. It spreads to the back surface of the organ. Rice. AT.

Superior mesenteric artery (a. mesenterica superior).

A. mesenterica superior, the superior mesenteric artery, departs from the anterior surface of the aorta immediately below the vermiform trunk, goes down and forward, into the gap between the lower edge of the pancreas in front and the horizontal part of the duodenum behind, enters the mesentery of the small intestine and descends to the right iliac fossa .

Branches, a. mesentericae superioris:

a) a. pancreatieoduodeiialis inferior goes to the right along the concave side of the duodeni towards aa. pancreaticoduodenales superiores;

b) aa. intestinales -- 10-16 branches that extend from a. mesenterica superior to the left side to the jejunum (aa. jejundles) and ileum (aa. ilei) intestine; along the way, they divide dichotomously and adjacent branches are connected to each other, which is why it turns out along aa. jejunales three rows of arcs, and along aa. ilei - two rows. Arcs are a functional device that provides blood flow to the intestines with any movements and positions of its loops. Many thin branches extend from the arcs, which encircle the intestinal tube in an annular fashion;

c) a. ileocolica departs from a.r mesenterica superior to the right, supplying with branches the lower part of the intestinum ileum and the caecum and sending to the appendix a. appendicularis, passing behind the final segment of the ileum;

d) a. colica dextra goes behind the peritoneum to the colon ascendens and near it is divided into two branches: ascending (going up towards a. colica media) and descending (descending towards a. ileocolica); branches depart from the resulting arcs to the adjacent sections of the large intestine;

e) a. colica media passes between the sheets of mesocolon transversum and, having reached the transverse colon, is divided into the right and left branches, which diverge in the respective directions and anastomose: the right branch -- with a. colica dextra, left - with a. colic sinistra

Inferior mesenteric artery (a. mesenterica inferior).

A. mesenterica inferior, the inferior mesenteric artery, departs at the level of the lower edge of the III lumbar vertebra (one vertebra above the aortic division) and goes down and slightly to the left, located behind the peritoneum on the anterior surface of the left psoas muscle.

Branches of the inferior mesenteric artery:

a) a. colica sinistra is divided into two branches: ascending, which goes towards flexura coli sinistra towards a. colica media (from a. mesenterica superior), and descending, which connects to aa. sigmoideae;

b) aa. sigmoideae, usually two to colon sigmoideum, ascending branches anastomose with branches of a. colica sinistra, descending - with

c) a. rectalis superior. The latter is a continuation of a. mesenterica inferior, descends at the root of the mesentery colon sigmoideum into the small pelvis, crossing in front of a. iliaca communis sinistra, and splits into lateral branches towards the rectum, joining as with aa. sigmoideae, as well as with a. rectalis media (from a. iliaca interna).

Thanks to the interconnection of branches aa. colicae dextra, media et sinistra and aa. rectales from a. iliaca interna, the large intestine along its entire length is accompanied by a continuous chain of anastomoses connected to each other.

Paired visceral branches: renal artery (a. renalis), middle adrenal artery (a. suprarenalis media).

Paired visceral branches depart in the order of the location of the organs, due to their laying.

1. A. suprarenalis media, the middle adrenal artery, starts from the aorta near the beginning of a. mesenterica superior and goes to gl. suprarenalis.

2. A. renalis, the renal artery, departs from the aorta at the level of the II lumbar vertebra almost at a right angle and goes in the transverse direction to the gate of the corresponding kidney. In caliber, the renal artery is almost equal to the superior mesenteric, which is explained by the urinary function of the kidney, which requires a large blood flow. The renal artery sometimes departs from the aorta in two or three trunks and often enters the kidney with multiple trunks not only in the region of the gate, but also along the entire medial edge, which is important to consider when pre-ligating the arteries during the kidney removal operation. At the hilum of the kidney a. renalis is usually divided into three branches, which in turn break up into numerous branches in the renal sinus (see "Kidney").

The right renal artery lies behind v. cava inferior, heads of the pancreas and pars descendens duodeni, left behind pancreas. V. renalis is located in front and slightly below the artery. From a. renalis extend upward to the lower part of the adrenal gland a. suprarenalis inferior, as well as a branch to the ureter.

3. A. testucularis (in women a. ovarica) is a thin long stem that starts from the aorta immediately below the beginning of a. renalis, sometimes from this latter. Such a high discharge of the artery that feeds the testicle is due to its laying in the lumbar region, where a. testicularis occurs at the shortest distance from the aorta. Later, when the testicle descends into the scrotum, along with it, a. testicularis, which by the time of birth descends along the anterior surface of m. psoas major, gives a branch to the ureter, approaches the inner ring of the inguinal canal and, together with the ductus deferens, reaches the testicle, which is why it is called a. testicularis. A woman has a corresponding artery, a. ovarica, does not go to the inguinal canal, but goes to the small pelvis and further as part of lig. suspensorium ovarii to the ovary.

Parietal branches of the abdominal aorta: lower phrenic artery (a. phrenica inferior), lumbar arteries (Aa. lumbales), median sacral artery (a. sacralis mediana).

1. A. phrenica inferior, inferior phrenic artery, supplies blood to the pars lumbalis of the diaphragm. She gives a small twig, a. suprarenalis superior, to the adrenal gland.

2. Ah. lumbales, lumbar arteries, usually four on each side (the fifth sometimes departs from a. sacralis mediana), correspond to the segmental intercostal arteries of the thoracic region. They supply blood to the corresponding vertebrae, spinal cord, muscles and skin of the lumbar region and abdomen.

3. A. sacralis mediana, median sacral artery, unpaired, represents the continuation of the aorta lagging behind in development (caudal aorta).

Acute violation of the mesenteric circulation

Etiology.

Acute violation of the mesentary circulation may be due to embolism or thrombosis of the mesentary vessels.
Emboli occur due to occlusion of blood vessels by an afferent blood clot.
Thrombosis - blockage of blood vessels formed at the site of a clot. Thrombus formation is facilitated by abdominal trauma, a drop in blood pressure, prolonged mesentarial spasm, vascular damage by atherosclerosis, nonspecific aortoarteritis, compression of vessels from the outside (tumor), hypercoagulability.

Anatomy.

superior mesenteric artery- supplies blood to almost the entire small intestine (except for the initial part of the duodenum), the cecum, the ascending colon and half of the transverse colon. It departs 1.25 cm below the celiac trunk. Crosses the splenic vein and pancreas. Then it goes in front of the processus uncinatus of the head of the pancreas and the lower part of the duodenum, descends between the layers of the mesentery into the right iliac fossa, where it anastomoses with its own branch - a. ileocolica. The vein next to her lies to her right.
Her branches:
- a. pancreaticoduodenalis inferior. It leaves at the level of the upper edge of the lower part of the duodenum and goes to the right between the head of the pancreas and the intestinal wall. Then it anastomoses with the superior pancreaticoduodenal artery. It supplies blood to the head of the pancreas, the descending and lower part of the duodenum.
- a.a. intestinales. Their number is usually 12-15. They run parallel to each other, then each branch is divided into two and anastomose with each other, forming arcs, bulging towards the intestines.
- a. ileocolica. Heads down and to the right behind the mesentery to the right iliac fossa. Gives two branches - the lower, anastomosing with the end of the superior mesenteric artery, and the upper, anastomosing with the right colonic artery. The lower branch gives branches to the ileum, caecum, ascending colon, and appendix.
- a. colic dexter. Goes to the right behind the mesentery. Gives a descending branch that anastomoses with a. ileocolica, and ascending, which anastomoses with a. colica media.
- a. colica media. It departs slightly below the pancreas. Goes in the mesentery of the transverse intestine. Gives right (anastomoses with a. colica dexter) and left (anastomoses with a. colica sinister, which departs from the inferior mesenteric artery) branches.

Inferior mesenteric artery- departs 3-4 cm above the division of the aorta, at the lower edge of the lower part of the duodenum. It supplies the left half of the transverse colon, the descending colon, the sigmoid colon, and most of the rectum. First, it goes in front of the aorta, then on the left. Then it descends into the small pelvis, where it turns into the superior hemorrhoidal artery, which runs in the mesentery of the sigmoid colon and ends at the upper part of the rectum.
Her branches:
- a. colica sinist ra .
- a.a. sigmoideae - 2-3 arteries.
- a. haemorrhoidalis superior.

Pathogenesis.

With embolism, rapid intestinal necrosis occurs (after 4-5 hours) with perforation and the development of peritonitis.
With thrombosis, pathomorphological changes develop more slowly, since a network of collaterals is formed in patients with a previous disease.
With blockage of the mesenteric veins, hemorrhagic necrosis develops.

Pathological anatomy.

There are three stages of pathomorphological changes occurring in the intestine:
one). Ischemia (in case of violation of the venous outflow - hemorrhagic impregnation).
2). Heart attack (gangrene, necrosis).
3). Peritonitis.
Morphologically, hemorrhagic, anemic and mixed myocardial infarction are distinguished.

The extent of intestinal damage depends on the location of the embolus or thrombus. Three segments are distinguished in the superior mesenteric artery:
I - from its mouth to the place of discharge of a.colica media. There is necrosis of the entire small intestine, and in half of the cases, both the blind and the right half of the transverse intestine.
II - from the place of discharge of a.colica media to the level of discharge of a.ileocolica. Necrosis of the terminal jejunum and the entire ileum occurs.
III - distal to a. ileocolica. Only the ileum is affected.

Thrombosis mainly affects the superior mesenteric artery.
Necrosis of the left half of the colon due to thrombosis of the inferior mesenteric artery is very rare. This is due to the fact that the inferior mesenteric artery anastomoses with arteries from the system of the internal iliac artery (rectal, genital) and with the superior mesenteric artery. The nutrition of the intestine is provided by the development of collaterals. Infection of the descending intestine develops with concomitant, and clinically significant, occlusive-stenotic lesions of the superior mesenteric artery.

Emboli also mainly affect the superior mesenteric artery (more than 90%), because it departs at a right angle (the celiac trunk and inferior mesenteric depart at a right angle).

Classification.

I. By type of violation:
one). Occlusal:
a) embolism
b) arterial thrombosis
c) vein thrombosis
d) covering the mouths of the arteries from the side of the aorta due to atherosclerosis and its thrombosis.
e) vascular occlusion in dissecting aortic aneurysm (shutdown symptom)
e) compression of blood vessels by tumors
g) ligation of blood vessels
2). Non-occlusive
a) with incomplete occlusion of the artery
b) angiospastic
c) associated with the centralization of hemodynamics.

II. According to the stages of the disease:
one). stage of ischemia.
2). stage of infarction.
3). stage of peritonitis.

III. With the flow:
one). With compensation of mesentary blood flow - there is a complete restoration of bowel function.
2). With subcompensation of mesentary blood flow - the viability of the intestine is maintained by collaterals.
3). With decompensation of the mesentary blood flow, an intestinal infarction occurs.

clinical picture.

The most typical symptoms are:
one). Abdominal pain. The nature of the pain is cramping or constant. Localization of pain is different depending on the level of vascular damage.
The most intense pain in the stage of ischemia, in the stage of a heart attack, it becomes somewhat dull, then, with peritonitis, it intensifies again.
2). Nausea and vomiting. They are reflexive.
3). Chair. It can be both diarrhea and intestinal obstruction; on this basis, two forms of the course of stroke are distinguished. Usually there is frequent loose stools with an admixture of blood.
Acute violation of the mesenteric circulation is accompanied by intestinal obstruction. Therefore, some authors consider it one of the types of intestinal obstruction.

Diagnostics.

Intestinal peristalsis weakens and then disappears.
A digital examination of the rectum reveals dark blood.
Radiographically - swollen intestinal loops with a horizontal level of fluid (signs of intestinal obstruction). However, inflated loops easily change their position on the latheroscope. Radiography recognizes intestinal obstruction, it is not essential in the recognition of stroke.
Ultrasound - reveals signs of intestinal obstruction, free fluid in the abdominal cavity. The main purpose is to exclude other pathology of the abdominal cavity.
Laparoscopy.
Angiography. The most accurate diagnostic method. It is believed that angiography must be performed in case of suspected stroke. It is necessary to identify patients with non-occlusive mesenteric ischemia, since they are not indicated for surgery (they need treatment with vasodilators).
CT is gradually replacing angiography in the diagnosis of stroke.

D / diagnostics.

CVA is differentiated primarily from mechanical intestinal obstruction, acute pancreatitis, acute cholecystitis, acute appendicitis, perforated gastric and duodenal ulcers.

Is it possible to distinguish stroke and mechanical intestinal obstruction before laparoscopy and angiography?

D / diagnosis of arterial and venous circulatory disorders?

Treatment.

In case of viability of intestinal loops, an embolus or thrombectomy is performed.
In the presence of a local occlusive-stenotic process, a reconstructive operation is performed - endarterectomy or aortomesenteric shunting (prosthetics).
With gangrene, the intestine is resected within healthy tissues. With a fuzzy demarcation line, an enterostomy is performed (since if an anastomosis is made, then there may be a failure of the sutures).
In doubtful cases of the viability of the intestine, revascularization is done first, and then the intestine is looked at.
In patients with a total lesion of the intestine, the operation is limited to revision of the abdominal organs.
With a high frequency of leaving non-viable tissues in the abdominal cavity, a second laparotomy (laparoscopy) is done.

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The treatment of acute disorders of the mesenteric circulation in the vast majority of cases involves emergency surgical intervention, which should be undertaken as soon as the diagnosis is established or there is a reasonable suspicion of this disease. Only active surgical tactics give real chances to save the lives of patients. Conservative methods of treatment should be used in combination with surgical ones, complementing, but in no case replacing them. Therapeutic and resuscitative measures taken in situations where the development of non-occlusive disorders of the mesenteric blood flow is possible are effective only until the appearance of clinical symptoms from the abdominal organs and can only be considered as preventive measures.

Surgical intervention should solve the following tasks:
1) restoration of mesenteric blood flow;
2) removal of non-viable parts of the intestine;
3) fight against peritonitis.

The nature and extent of surgical intervention in each case is determined by a number of factors: the mechanism of mesenteric circulation disorders, the stage of the disease, the location and extent of the affected areas of the intestine, the general condition of the patient, surgical equipment and the experience of the surgeon. All types of operations are reduced to three approaches:
1) vascular interventions;
2) resection of the intestine;
3) combinations of these methods.

Obviously, vascular operations are the most appropriate. We are usually talking about an intervention on the superior mesenteric artery. Restoration of blood flow through the mesenteric arteries during the first 6 hours after occlusion usually leads to the prevention of intestinal gangrene and the restoration of its functions. However, when a patient is admitted at a later date, when irreversible changes occur in a more or less extended section of the intestine, in addition to its removal, an operation on the mesenteric vessels may be necessary to restore blood flow in its still viable sections. That is why in most cases it is necessary to combine vascular operations and resection interventions.

The main stages of surgical intervention include:

• surgical access;
• revision of the intestine and assessment of its viability;
• revision of the main mesenteric vessels;
• restoration of mesenteric blood flow;
• bowel resection according to indications;
• decision on the timing of the anastomosis; sanitation and drainage of the abdominal cavity.

Intestinal revision necessarily precedes active surgical actions. The subsequent actions of the surgeon depend on the correct determination of the nature, localization, prevalence and severity of intestinal damage. The detection of total gangrene of the small intestine forces us to confine ourselves to a trial laparotomy, since intestinal transplantation, one of the most difficult operations in modern medicine, despite the progress made in recent years, is not yet the lot of emergency surgery.

Intestinal viability assessment is based on known clinical criteria: color of the intestinal wall, determination of peristalsis and pulsation of the mesenteric arteries. Such an assessment in cases of apparent necrosis is quite simple. Determining the viability of an ischemic gut is much more difficult. For violations of the mesenteric circulation, the "mosaic" of ischemic disorders is characteristic: neighboring sections of the intestine can be in different conditions of blood circulation. Therefore, after the vascular stage of surgical intervention, a repeated thorough examination of the intestine is necessary. In some cases, it is advisable to perform it during relaparotomy one day after the first operation.

Revision of the main mesenteric vessels- the most important stage of surgical intervention. The revision of the arteries begins with the examination and palpation of the vessels near the intestine. Normally, the pulsation is clearly visible visually. If the mesenteric blood flow is disturbed, the pulsation along the edge of the intestine disappears or becomes weak. The developing edema of the mesentery and intestinal wall also prevents it from being detected. It is convenient to determine the pulsation along the mesenteric edge by grasping the intestine with the thumb, index and middle fingers of both hands.

The pulsation of the trunk of the superior mesenteric artery can be determined using two different techniques (Fig. 50-2).

Rice. 50-2. Methods for determining the pulsation of the superior mesenteric artery.

The first is as follows: under the mesentery of the small intestine, the thumb of the right hand, feeling the pulsation of the aorta, is advanced as high as possible to the place of origin of the superior mesenteric artery. At the same time, the root of the mesentery of the small intestine is grasped from above with the index finger immediately to the right of the duodenal-skinny bend.

Second reception - the right hand is brought under the first loop of the jejunum and its mesentery (with the thumb located above the intestine) and slightly pulled down. With the fingers of the left hand, a cord is found in the mesentery, in which the superior mesenteric artery is palpated. Along its trunk with a non-greasy mesentery, an embolus can sometimes be palpated. Indirect signs of thrombosis are pronounced atherosclerosis of the aorta and the presence of a plaque in the region of the artery mouth. By moving the small intestine and its mesentery to the right, it is possible to determine the pulsation of the aorta and the inferior mesenteric artery.

In doubtful cases (with mesenteric edema, systemic hypotension, severe obesity), it is advisable to isolate the trunks of the mesenteric arteries and revise them. This is also necessary to perform an intervention on them, aimed at restoring blood circulation in the intestines.

Exposing the superior mesenteric artery can be made from two approaches: anterior and posterior (Fig. 50-3).

Rice. 50-3. Exposure of the superior mesenteric artery: (1 - superior mesenteric artery; 2 - middle colic artery; 3 - iliocolic artery; 4 - aorta; 5 - inferior vena cava; 6 - left renal vein; 7 - inferior mesenteric artery): a - anterior access; b - rear access.

Anterior access more simple and it is usually used for embolism. To do this, the transverse colon is brought into the wound and its mesentery is pulled. The mesentery of the small intestine is straightened, the loops of the intestines are moved to the left and downwards. The initial section of the mesentery of the jejunum is also stretched. The posterior leaf of the parietal peritoneum is cut longitudinally from the ligament of Treitz along the line connecting it with the ileocecal angle. With a fatty mesentery or its edema, you can use the middle colon artery as a guide, exposing it towards the mouth, moving gradually towards the main arterial trunk. Large branches of the superior mesenteric vein, lying above the trunk of the artery, are mobilized, displaced, but in no case do not cross. The trunk and branches of the superior mesenteric artery are exposed for 6-8 cm. Anterior access usually does not expose the first 2-3 cm of the trunk and its orifice, covered with a fairly dense fibrous tissue. The superior mesenteric vein is exposed in a similar way.

For posterior access(to the left in relation to the root of the mesentery of the small intestine), the intestinal loops are moved to the right and down. The ligament of Treitz is stretched and dissected, and the duodeno-jejunal flexure is mobilized. Next, the parietal peritoneum is dissected above the aorta in such a way that a right-curved incision is obtained. It is better to dissect tissues from below: the aorta is exposed, then the left renal vein, which is mobilized and retracted downward. Above the vein, the mouth of the superior mesenteric artery is exposed. It is advisable to use this access for thrombosis, since atherosclerotic plaque is more often located in the region of the artery mouth. To perform a possible vascular reconstruction, it is necessary to allocate a section of the aorta above and below the orifice.

For the purposes of highlighting inferior mesenteric artery extend the longitudinal incision of the peritoneum downward along the aorta. The trunk of the artery is found along its left lateral contour.

Restoration of mesenteric blood flow produced in various ways, depending on the nature of the vascular occlusion. Embolectomy from the superior mesenteric artery is usually performed from the anterior approach (Fig. 50-4).

Rice. 50-4. Scheme of indirect embolectomy from the superior mesenteric artery: a, b - stages of the operation; 1 - middle colic artery.

A transverse arteriotomy is performed 5-7 mm above the orifice of the middle colic artery so that its catheter revision can be carried out along with the iliocolic and at least one of the intestinal branches. Embolectomy is performed using a Fogarty balloon catheter. The arteriotomy is sutured with separate synthetic sutures on an atraumatic needle. To prevent angiospasm, novocaine blockade of the mesenteric root is performed. The effective restoration of blood flow is judged by the appearance of pulsation of the trunk and branches of the superior mesenteric artery, the restoration of the pink color of the intestine and peristalsis.

Vascular operations for arterial thrombosis are technically more difficult, they have to be performed in an unknown state of the distal mesenteric bed, and they give worse results. Due to the predominant localization of thrombosis in the I segment of the trunk of the superior mesenteric artery, posterior access to the vessel is indicated.

Depending on the clinical situation, perform thrombin thymectomy followed by suturing of an autovenous or synthetic patch (Fig. 50-5), bypass, reimplantation of the artery into the aorta, prosthesis of the superior mesenteric artery.

Rice. 50-5. Scheme of thrombin thymectomy from the superior mesenteric artery.

From a technical point of view, thrombinthymectomy is the simplest. To prevent retrombosis, it is advisable to make a longitudinal incision of the artery longer than the area of ​​the removed intima, and be sure to hem the distal edge of the intima with U-shaped sutures.

Shunt operations are promising when the trunk of the superior mesenteric artery is anastomosed with the splenic artery, the right common iliac artery, or the aorta. Retrombosis after these interventions occurs less frequently. Prosthetics of the superior mesenteric artery is indicated for its significant thrombosis. The prosthesis can be sutured after resection of the artery in the first segment, between the aorta and the distal end of the artery, and also connect the mesenteric bed to the right common iliac artery.

Thrombectomy from superior mesenteric vein primarily aimed at preventing portal vein thrombosis. The trunk of the superior mesenteric vein is exposed below the mesentery of the transverse colon, a transverse phlebotomy is performed, and thrombotic masses are removed using a Fogarty catheter. With a sharp edema of the mesentery, when it is difficult to expose the trunk of the superior mesenteric vein, thrombectomy can be performed through a large intestinal branch.

Bowel resection in case of mesenteric circulation disorders, it can be used as an independent intervention, or in combination with vascular operations. As independent operation resection is indicated for thrombosis and embolism distal branches upper or lower mesenteric arteries, limited in length venous thrombosis, decompensated non-occlusive disorders blood flow. In these cases, the extent of the intestinal lesion, as a rule, is small, therefore, after resection, digestive disorders usually do not occur.

At the same time, bowel resection in case of occlusions of the I segment of the superior mesenteric artery as an independent operation is unpromising, and if total necrosis has not yet occurred in accordance with the level of occlusion, it should always be combined with a vascular operation.

The rules for performing bowel resection are different depending on whether it is performed as an independent operation or in conjunction with intervention on the vessels. In case of occlusion of the branches of the mesenteric arteries, when no intervention is performed on them, one should deviate from the visible boundaries of the non-viable section of the intestine by 20-25 cm in each direction, taking into account the outstripping dynamics of necrotic changes in the inner layers of the intestine. When crossing the mesentery, it is necessary to make sure that, in accordance with the level of resection, there are no thrombosed vessels in it, and the crossed vessels bleed well. If the resection is performed together with a vascular operation, then after the restoration of blood circulation, only areas of the obviously non-viable intestine are removed, the resection border may pass closer to the necrotic tissues. In such a situation, the tactics of delayed anastomosis during relaparotomy is especially justified.

The predominance of high occlusion and late terms of surgical interventions for acute disorders of the mesenteric circulation quite often determine the performance of subtotal resections of the small intestine. Due to the wide range of the length of the small intestine, the length of the removed segment itself is not decisive in terms of prognosis. Much more important is the size of the remaining intestine. The critical value in most initially relatively healthy patients is about 1 m of the small intestine.

When performing a resection for a heart attack, some technical rules must be observed. Along with the intestine affected by a heart attack, it is necessary to remove the altered mesentery with thrombosed vessels, so it is crossed not along the edge of the intestine, but significantly retreating from it. In case of thrombosis of the branches of the superior mesenteric artery or vein, after dissection of the peritoneal sheet 5-6 cm from the edge of the intestine, the vessels are isolated, crossed and ligated. With extensive resections with the intersection of the trunk of the superior mesenteric artery or vein, a wedge-shaped resection of the mesentery is performed. The trunk of the superior mesenteric artery is crossed in such a way as not to leave a large "blind" stump next to the outgoing pulsating branch.

After resection within the limits of reliably viable tissues, an end-to-end anastomosis is performed according to one of the generally accepted methods. If there is a significant discrepancy between the ends of the resected intestine, a side-to-side anastomosis is formed.

Delayed anastomosis often becomes the most appropriate solution. The reasons for such tactics are doubts about the exact determination of the viability of the intestine and the extremely difficult condition of the patient during surgery. In such a situation, the operation is completed by suturing the stumps of the resected intestine and active nasointestinal drainage of the adducting section of the small intestine. After stabilization of the patient's condition against the background of ongoing intensive therapy (usually a day later), during relaparotomy, the viability of the intestine in the resection zone is finally assessed, if necessary, resection is performed and only after that an interintestinal anastomosis is applied.

When signs of non-viability of the caecum and ascending colon are found, it is necessary to perform a right-sided hemicolectomy along with resection of the small intestine. In this case, the operation is completed with an ileotransversostomy.

Necrotic changes found in the left half of the colon require resection of the sigmoid colon (with thrombosis of the branches of the inferior mesenteric artery or non-occlusive disturbance of mesenteric blood flow) or left-sided hemicolectomy (with occlusion of the trunk of the inferior mesenteric artery). Due to the serious condition of the patients and the high risk of failure of the primary colonic anastomosis, the operation, as a rule, should be completed with a colostomy.

When intestinal gangrene is detected, it is advisable to apply the following procedure for surgical intervention. First, resection of clearly necrotic intestinal loops is performed with a wedge-shaped excision of the mesentery, leaving areas of questionable viability. In this case, the operation on the mesenteric arteries is delayed by 15-20 minutes, but the delay is compensated by better conditions for further operation, since the swollen, non-viable intestinal loops make it difficult to intervene on the mesenteric vessels. In addition, such an operation procedure prevents a sharp increase in endotoxicosis after the restoration of blood flow through the vessels of the mesentery, its possible phlegmon, and to a certain extent stops infection of the abdominal cavity and the development of purulent peritonitis. The stump of the resected intestine is sutured with a UKL-type device and placed in the abdominal cavity. Then an intervention is performed on the vessels. After the elimination of arterial occlusion, the viability of the remaining intestinal loops can be finally assessed, the issue of the need for additional bowel resection and the possibility of anastomosis can be decided.

It is advisable to complete the intervention on the intestine with nasointestinal intubation, which is necessary to combat postoperative paresis and endotoxicosis. Sanitation and drainage of the abdominal cavity is performed in the same way as in other forms of secondary peritonitis.

In the postoperative period, intensive care includes measures aimed at improving systemic and tissue circulation, which is especially important for the condition of the intestinal microcirculatory bed, maintaining adequate gas exchange and oxygenation, correcting metabolic disorders, combating toxemia and bacteremia. It should be borne in mind that resection of a non-viable intestine does not eliminate severe systemic disorders, which may even worsen in the immediate postoperative period.

Low resistance of patients predisposes to the development of general surgical complications (abdominal surgical sepsis, pneumonia, pulmonary embolism). These complications can be prevented by complex intensive therapy. At the same time, any conservative measures in case of recurrence or progression of vascular occlusion will be useless. The main diagnostic efforts in the postoperative period should be aimed at identifying ongoing intestinal gangrene and peritonitis.

In patients with ongoing gangrene of the intestine note persistent leukocytosis and a pronounced stab shift with a tendency to increase, ESR increases. The development of hyperbilirubinemia and the progressive accumulation of nitrogenous wastes in the blood are characteristic signs of ongoing intestinal gangrene, which indicate a deep toxic lesion of the liver and kidney parenchyma. Urination progressively decreases until anuria, despite the large amount of fluid administered and significant doses of diuretics. Urinalysis reveals the development of toxic nephrosis, manifested in persistent and increasing proteinuria, cylindruria and microhematuria. Reasonable suspicions of ongoing gangrene of the intestine serve as indications for emergency relaparotomy.

Early targeted (programmed) relaparotomy performed in order to control the condition of the abdominal cavity or to impose a delayed anastomosis. The need for repeated revision of the abdominal cavity arises when, after revascularization, signs of dubious viability of the intestine (edema, cyanosis of the intestine, weakened peristalsis and pulsation of the arteries along the mesenteric margin) persist throughout the entire intestine (especially the small intestine) or on the remaining small part of it after extensive resection.

Signs of doubtful viability usually disappear within 12-24 hours, or obvious gangrene of the intestine develops, and in operable cases, during a programmed relaparotomy, limited areas of the affected intestine can be removed without waiting for the development of widespread peritonitis and intoxication. The time for relaparotomy is 24 to 48 hours after the initial operation. Repeated intervention to a certain extent aggravates the patient's condition. At the same time, this is an effective way to save a significant part of patients with mesenteric blood flow disorders.

B.C. Saveliev, V.V. Andriyashkin

Portal vein, v. portae hepatis , collects blood from unpaired organs of the abdominal cavity.

It is formed behind the head of the pancreas as a result of the confluence of three veins: the inferior mesenteric vein, v. mesenterica inferior, superior mesenteric vein, v. mesenterica superior, and splenic vein, v. splenica.

The portal vein from the place of its formation goes up and to the right, passes behind the upper part of the duodenum and enters the hepatoduodenal ligament, passes between the sheets of the latter and reaches the gate of the liver.

In the thickness of the ligament, the portal vein is located with the common bile and cystic ducts, as well as with the common and proper hepatic arteries in such a way that the ducts occupy the extreme position on the right, to the left are the arteries, and behind the ducts and arteries and between them is the portal vein.

At the gates of the liver, the portal vein divides into two branches - the right and left, respectively, the right and left lobes of the liver.

Right branch, r. dexter, wider than left; it enters through the gates of the liver into the thickness of the right lobe of the liver, where it is divided into anterior and posterior branches, r. anterior et r. posterior.

Left branch, r. sinister, longer than right; heading to the left side of the gate of the liver, it, in turn, divides along the way into a transverse part, pars transversa, giving branches to the caudate lobe - caudal branches, rr. caudati, and the umbilical part, pars umbilicalis, from which the lateral and medial branches depart, rr. laterales et mediales, into the parenchyma of the left lobe of the liver.

Three veins: inferior mesenteric, superior mesenteric and splenic, from which v. portae are called roots of the portal vein.

In addition, the portal vein receives the left and right gastric veins, vv. gastricae sinistra et dextra, prepyloric vein, v. prepylorica, paraumbilical veins, vv. paraumbilicales, and gallbladder vein, v. cystica.

1. Inferior mesenteric vein, v. mesenterica inferior , collects blood from the walls of the upper part of the straight, sigmoid colon and descending colon and with its branches corresponds to all branches of the inferior mesenteric artery.

It begins in the pelvic cavity as the superior rectal vein, v. rectalis superior, and in the wall of the rectum with its branches is connected with the rectal venous plexus, plexus venosus rectalis.

The superior rectal vein goes up, crosses the iliac vessels in front at the level of the left sacroiliac joint and receives the sigmoid intestinal veins, vv. sigmoideae, which follow from the wall of the sigmoid colon.

The inferior mesenteric vein is located retroperitoneally and, heading up, forms a small arc, facing the bulge to the left. Having taken the left colic vein, v. colica sinistra, the inferior mesenteric vein deviates to the right, passes immediately to the left of the duodenal-lean bend under the pancreas and most often connects with the splenic vein. Sometimes the inferior mesenteric vein flows directly into the portal vein.

2. Superior mesenteric vein, v. mesenterica superior , collects blood from the small intestine and its mesentery, caecum and appendix, ascending and transverse colon and from the mesenteric lymph nodes of these areas.

The trunk of the superior mesenteric vein is located to the right of the artery of the same name, and its branches accompany all the branches of this artery.

The superior mesenteric vein begins at the ileocecal angle, where it is called the ileocolic vein.

Ileococolic intestinal vein, v. ileocolica, collects blood from the terminal ileum, appendix (vein of the appendix, v. appendicularis) and the caecum. Heading up and to the left, the iliac-colon-intestinal vein continues directly into the superior mesenteric vein.

The superior mesenteric vein is located at the root of the mesentery of the small intestine and, forming an arc with a bulge to the left and down, receives a number of veins:

a) jejunal and ileo-intestinal veins, vv. jejunales et ileales, only 16 - 20, go to the mesentery of the small intestine, where they accompany the branches of the small intestinal arteries with their branches. Intestinal veins flow into the superior mesenteric vein on the left;

b) right colonic veins, vv. colicae dextrae, go retroperitoneally from the ascending colon and anastomose with the ileocolic-intestinal and middle colon-intestinal veins;

c) middle colic vein, v. colica media, located between the sheets of the mesentery of the transverse colon; it collects blood from the right flexure of the colon and the transverse colon. In the region of the left flexure of the colon, it anastomoses with the left colonic vein, v. colica sinistra, forming a large arcade;

d) right gastroepiploic vein, v. gastroepiploica dextra, accompanies the artery of the same name along the greater curvature of the stomach; collects blood from the stomach and greater omentum; at the level of the pylorus flows into the superior mesenteric vein. Before confluence, it takes pancreatic and pancreatoduodenal veins;

e) pancreatoduodenal veins, vv. pancreaticoduodenales, repeating the path of the arteries of the same name, collect blood from the head of the pancreas and duodenum;

e) pancreatic veins, vv. pancreaticae, depart from the parenchyma of the head of the pancreas, passing into the pancreatoduodenal veins.

3. Splenic vein, v. splenica , collects blood from the spleen, stomach, pancreas and greater omentum.

It is formed in the region of the gate of the spleen from the numerous veins emerging from the substance of the spleen.

Here the splenic vein receives the left gastroepiploic vein, v. gastroepiploica sinistra, which accompanies the artery of the same name and collects blood from the stomach, greater omentum, and short gastric veins, vv. gastricae breves, which carry blood from the fundus of the stomach.

From the gate of the spleen, the splenic vein goes to the right along the upper edge of the pancreas, located below the artery of the same name. It crosses the anterior surface of the aorta just above the superior mesenteric artery and merges with the superior mesenteric vein to form the portal vein.

The splenic vein receives the pancreatic veins, vv. pancreaticae, mainly from the body and tail of the pancreas.

In addition to the indicated veins that form the portal vein, the following veins flow directly into its trunk:

a) prepyloric vein, v. prepylorica, begins in the pyloric region of the stomach and accompanies the right gastric artery;

b) gastric veins, left and right, v. gastrica sinistra et v. gastrica dextra, go along the lesser curvature of the stomach and accompany the gastric arteries. In the region of the pylorus, the veins of the pylorus flow into them, in the region of the cardial part of the stomach - the veins of the esophagus;

c) paraumbilical veins, vv. paraumbilicales (see Fig. 829, 841), begin in the anterior abdominal wall in the circumference of the umbilical ring, where they anastomose with the branches of the superficial and deep superior and inferior epigastric veins. Heading to the liver along the round ligament of the liver, the paraumbilical veins either connect into one trunk, or several branches flow into the portal vein;

d) gall bladder vein, v. cystica, flows into the portal vein directly into the substance of the liver.

In addition, in this area in v. portae hepatis, a number of small veins flow from the walls of the portal vein itself, the hepatic arteries and ducts of the liver, as well as the veins from the diaphragm, which reach the liver through the falciform ligament.