Abdominal aortic aneurysm resection

Abdominal aortic aneurysm is used for the treatment of abdominal aortic aneurysm. Abdominal aortic aneurysms are almost exclusively caused by atherosclerosis, and aneurysms caused by syphilis or fungal infections are rare. The intimal thickening, thickening, ulceration and degeneration of the medial membrane make the arterial wall unable to withstand the continuous impact of blood flow and gradually expand and bulge to form an aneurysm. There are many thrombosis in the tumor cavity. It usually affects the abdominal aorta below the plane of the renal artery to the bifurcation, and sometimes to the common iliac artery. The patient may be asymptomatic, or may have complaints such as abdominal fullness and dull pain, and some may find pulsating masses. The lesions are progressive and have a spontaneous rupture trend. Once ruptured, only a few patients can be rescued. Most of the patients are middle-aged and elderly people over 50 years old, often accompanied by hypertension and coronary heart disease. X-ray and B-mode ultrasound are helpful for diagnosis, but more valuable are CT and angiography. CT can accurately measure the size of the aneurysm; digital subtraction angiography can determine the relationship between the hemangioma and the renal artery, the presence of the radial artery and other visceral vessels, and the blood supply to the inferior mesenteric artery. Surgery is the only effective treatment. Aneurysm resection and abdominal aorta-iliac artery or abdominal aorta-femoral artery bridging are recognized as standard procedures. Treatment of diseases: abdominal aortic aneurysm Indication In principle, all patients with a good abdominal aortic aneurysm should undergo surgery. The larger the tumor, the greater the risk of rupture, especially for symptomatic or hypertensive patients. It is reported that 50% of aneurysms <6 cm in diameter can survive for 5 years; those with 6 cm are only 6%. A 6cm diameter abdominal aortic aneurysm ruptures every year. It is not uncommon for a tumor to rupture <5cm, so it is wise to perform surgery as soon as possible. On the other hand, abdominal aortic aneurysm resection is a risky operation. Interruption and opening of the abdominal aorta during surgery can cause significant changes in hemodynamics, and patients have some basic diseases. Some are still quite serious. Among the known high-risk factors, heart disease ranked first, including unstable angina, congestive heart failure, and recent history of myocardial infarction; followed by respiratory diseases (dyspnea, intermittent oxygen inhalation) and renal insufficiency (creatinine > 265mol/L or 3mg/dl, depending on dialysis treatment). Age is a relatively minor factor. To decide whether to perform surgery, you must first conduct an in-depth examination of the patient and master the detailed information on the two aspects of hemangioma and organ function. On this basis, we must carefully weigh the risk of aneurysm rupture and surgery, and make a decisive decision. At current levels, the surgical mortality rate is about 5%, and myocardial infarction is the leading cause of death. Contraindications Less than 3 months after myocardial infarction, difficult to correct heart failure and heart rhythm disorders, severe myocardial insufficiency, advanced malignant tumors are contraindications. Preoperative preparation 1. Actively treat basic diseases, especially heart, lung and kidney diseases, so that patients can meet the surgery as best as possible. 2. Smoking is not allowed for more than 1 month before surgery. Instructing patients to take deep breathing exercises, postoperative intermittent deep breathing can greatly help reduce atelectasis and other respiratory complications. 3. Prepare enough blood (1500 ~ 2000ml). 4. Intravenous infusion of crystal balance solution 1000 ~ 1500ml within 12h before surgery. 5. Broad-spectrum antibiotics were given intravenously 30 minutes before surgery to prevent infection. 6. Place the stomach tube and the urinary tube. Surgical procedure Incision A midline incision from the xiphoid to the pubic symphysis. 2. Exposing an aneurysm After thorough investigation, all the small intestines are wrapped with a wet gauze pad, blocked to the upper right (partially placed outside the abdominal cavity), and the transverse colon is pulled upwards, and the peritoneum is cut from the ligament of the flexor to the lower part of the iliac crest. Free to both sides, revealing aneurysms and bilateral radial arteries. 3. Anatomical aneurysm proximal abdominal aorta The third and fourth segments of the duodenum were separated and appropriately separated from the superior mesenteric vein for further retraction to the upper right. Close to the aorta of the abdominal aorta and blunt dissection until the left renal vein, separate it from the abdominal aorta and push it upwards. For this purpose, the left internal spermatic vein can be cut. Free the side of the aorta on both sides of the aorta, so that the aorta can be pinched from the spine to the front, but it is not necessary to make a ring free to avoid bleeding from the lumbar arteriovenous tear. Most of the inferior mesenteric artery from the aneurysm has been severely stenotic or occluded, and the ligation can be cut from the root. However, except for a few cases, it needs to be replanted after cutting. Treatment of the inferior mesenteric artery: In order to expose and dissect the abdominal aorta, the inferior mesenteric artery (IMA) is usually cut off, usually without causing ischemia in the left colon. However, if the preoperative angiography reveals that the IMA is grossly distorted and the superior mesenteric artery has insufficient blood supply, it may be necessary to replant the severed IMA. In the surgical exploration, IMA can be tried to block the blood flow of the left colon, and the intraoperative Doppler test is very helpful. If it is preliminarily judged that it needs to be re-implanted, the aortic wall of the IMA root should be pulled out to form a trumpet shape with the IMA. The gap in the aorta is sutured. At this point, try to open the IMA blocker. If there is enough blood to return, the IMA does not need to be replanted and can be ligated. Otherwise, it is implanted on the artificial blood vessel after the bridge is completed. Fortunately, this situation is rare. 4. Exposing the common arteriovenous fistula Find the ureter and protect it. Properly separate the common iliac artery can be pinched by the operator's finger (to ensure that the blocking forceps can not be slipped in place), but not full circumference separation. The patient was heparinized by intravenous injection of heparin 100 U/kg. The bilateral common iliac artery and abdominal aorta were sequentially blocked with a non-invasive forceps. The distal side is first blocked to prevent lower extremity arterial embolization caused by intimal atherosclerotic plaque or thrombus detachment during proximal clamping. 5. Partially open aneurysm wall It is best to use an electric knife to cut the outer and middle membranes longitudinally along the midline and try not to cut into the tumor cavity. The upper end stops at the junction of the tumor and the normal artery, and is changed into a transverse incision to make it T-shaped. The transverse incision accounts for about 40% to 50% of the circumference. If the common arteries of the two jaws are not involved, the same T-shaped incision can be made on the bifurcation to prepare for anastomosis with the distal end of the transplanted single-tube artificial blood vessel. However, in about half of the cases, the common iliac artery is affected to varying degrees, and it is necessary to extend the incision to open it. The tumor is removed with a shank. The stripping plane can be between the middle and inner membranes, or between the inner membrane and the immobilized thrombus adhering thereto. 6. Enter the tumor cavity Peeling to a certain range, you can enter the tumor cavity, at which time blood is pouring out. Immediately cut the entire length of the aneurysm wall with the original incision, rapidly remove the intratumoral thrombus and thicken the hard and brittle inner membrane. Most of the lumbar artery has been occluded, and those who are not occluded can use the 4-0 non-absorption line to do the "8" suture to stop bleeding. If the inferior mesenteric artery has not been found during the exposure of the aneurysm, it can be recognized from the inner wall of the cavity and sewn. 7. Polyester blood vessel pre-coagulation treatment 8. Do a proximal end anastomosis First, cut the thick arm of the herringbone-shaped polyester blood vessel as needed (the artificial blood vessel will be significantly expanded after the blood is passed, and it should be cut in the elongated state when trimming). Since the posterior wall of the aorta is not severed, the boundary between the normal arterial wall and the aneurysm must be recognized (generally not difficult). Use a 3-0 double needle thread to make a 1-needle valgus suture in the middle of the posterior wall of the polyester vessel and knot it. Then use these two needles to make continuous valgus stitching to both sides. The continuous stitching turns to the front wall and continues until it meets with the opposite side line, and the last two lines are knotted to each other. 9. Check the anastomotic sealing The vascular clamp clamps the distal end of the artificial blood vessel, and slowly releases the blocking forceps of the abdominal aorta, and the artificial blood vessel is immediately filled. If there is obvious blood leakage in the anastomosis, simple suture or suture suture repair. Small blood leaks can be resolved by brief compression. After confirming that there is no blood leakage, the artificial blood vessel close to the anastomosis is blocked, and the distal blocking forceps is opened to evacuate the blood in the artificial blood vessel cavity. 10. Do a distal anastomosis If the condition permits an anastomosis above the aortic bifurcation, the operation is relatively easy. However, it is necessary to carefully check the condition of the posterior wall of the blood vessel in the anastomosis. If there is an intimal hardened plaque, it should be removed, and then it can be judged whether it can be firmly sutured. The anastomosis method is the same as the proximal anastomosis. If the proximal iliac artery is affected and the distal segment is intact, the thin arm of the herringbone-shaped polyester vessel is anastomosed with its end-end or end-to-side. If the entire common iliac artery is involved and the external iliac artery is intact, it can also be anastomosed with the external iliac artery. When the blood vessels are anastomosed, pay attention to the needle from the endometrium and the needle from the outer membrane instead of the opposite to prevent the intimal membrane that is easily peeled off from being provoked. Before the last needle of the distal anastomosis is knotted, the proximal and distal blocking forceps are opened separately to expel air and blood clots in the artificial blood vessel. After knotting, also check for blood leaks, see "abdominal aorta-sacral artery bridging and abdominal aorta-femoral bridging." After confirming that there is no blood leakage, the contralateral arm is clamped under the bifurcation of the artificial blood vessel, and the blocking clamps on the same side are removed to restore the blood supply to the lower limb. When the radial artery is extensively unable to be used for anastomosis, it can only be bridged to the femoral artery. To this end: 1 sutured the common iliac artery end; 2 incision in the femoral triangle, revealing the femoral artery; 3 along the anterior external iliac artery to do extraperitoneal tunnel, the artificial blood vessel leading to the thigh triangle; 4 and femoral artery end - Lateral anastomosis, see "abdominal aorta-radial artery bridging and abdominal aorta-femoral bridging" for details. After the completion of the anastomosis, intravenous injection of protamine 25 ~ 50mg in order to stop bleeding. 11. Close the peritoneum and aneurysm wall In order to prevent arterial bowel fistula, artificial blood vessels, especially anastomosis, must be properly covered and separated from the duodenum and small intestine. After the wall of the aneurysm was completely hemostasis, it was wrapped around the polyester blood vessel. If there is a surplus in the wall of the capsule, it can be overlapped and stitched, and it is not necessary to trim it to avoid re-healing. The posterior peritoneum and the wall of the capsule can also be sutured together. For this purpose, the peritoneal rupture is sutured continuously from the upper end. When the level of the anastomosis is reached, the wall of the capsule is sutured together. Note that when the upper edge of the wall of the capsule is sewn, a needle of the outer membrane of the proximal vessel of the anastomosis is required to make the coverage of the anastomosis more reliable. 12. The upper boundary of the aneurysm is very high, close to the level of the renal artery opening, and it is impossible to place the blocking forceps and complete the anastomosis solution in the usual position. Occasionally, the upper boundary of the aneurysm is very high, close to the level of the renal artery opening, and it is impossible to place the blocking forceps and complete the anastomosis in the usual position. The simpler solutions are as follows: 1 Block the abdominal aorta at the diaphragmatic hernia (see the repair of the inferior vena cava injury below the renal vein plane), clamp the renal arteries on both sides and insert the balloon catheter into the celiac artery and mesentery. Arterial, water injection into the sac to block retrograde blood flow, can complete the tumor removal and anastomosis. 2 Insert the large balloon catheter through the artificial blood vessel into the abdominal aorta to the level of the renal artery opening, so that the filled water balloon simultaneously blocks the abdominal aorta and the renal artery on both sides, providing conditions for the subsequent operation. Blocking the visceral artery for 30 minutes under temperature does not have obvious adverse consequences. A higher abdominal aortic aneurysm is required to enter through the large thoracoabdominal incision from the left retroperitoneal approach and reconstruct the celiac artery, superior mesenteric artery, and renal artery opening. complication 1. myocardial infarction. 2. Atelectasis and lung infections. 3. Internal bleeding. 4. Distal arterial embolism caused by blood clots or sclerosing plaques. 5. Erectile dysfunction. Do not widely dissipate the bifurcation of the abdominal aorta (especially to the left) to reduce the chance of damaging the nerve plexus. It has been suggested that a lateral-lateral anastomosis to the common iliac artery can be added midway through the abdominal aorta-femoral artery to improve the blood supply to the inferior epigastric artery, which is helpful for the prevention and treatment of vasculogenic impotence.