A 72-year-old man was brought to the emergency department with an abdominal aortic aneurysm (an expansion of the infrarenal abdominal aorta). The aneurysm measured 10 cm, and after discussion with the patient it was scheduled for repair.
The surgical and endovascular treatment options were explained to the patient.
Treatment of abdominal aortic aneurysms has been, for many years, an operative procedure where the dilation (ballooning) of the aorta is resected and a graft is sewn into position. A modern option is to place a graft to line the aneurysm from within the artery (endovascular aneurysm repair). In this technique the surgeon dissects the femoral artery and makes a small hole in it. The graft is compressed within a catheter and the catheter is passed through the femoral artery and the iliac arterial system into the distal abdominal aorta. The graft can then be released inside the aorta, effectively relining it to prevent further expansion of the aneurysm.
Occasionally the relined aneurysm may continue to enlarge after the endovascular graft has been placed and a cause needs to be identified.
A Doppler ultrasound investigation of the abdomen and a CT scan revealed there was flow between the endovascular lining and the wall of the aneurysm.
The likely sources for this bleeding were assessed.
The graft usually begins below the level of the renal arteries and divides into two limbs that end in the common iliac arteries. The aneurysm may continue to be fed from any vessels between the graft and the aneurysm wall. These vessels can include the lumbar arteries and the inferior mesenteric artery. Interestingly, blood usually flows from the abdominal aorta into the inferior mesenteric artery and the lumbar arteries; however, with the changes in flow dynamics with the graft in place, blood may flow in the opposite direction through these branches, thereby leading to enlargement of the aneurysm.
Blood flow was from the superior mesenteric artery into the aneurysm sac.
Above the level of the graft the superior mesenteric artery arises normally. From the right colic and middle colic branches a marginal branch around the colon anastomoses, in the region of the splenic flexure, with marginal branches from the inferior mesenteric artery (this can become a hypertrophied vessel known as the marginal artery of Drummond). In this situation, blood passed retrogradely into the inferior mesenteric artery, filling the aneurysm and allowing it to remain pressurized and expand.
The inferior mesenteric artery was ligated laparoscopically and the aneurysm failed to expand further. Over the ensuing 6 months the aneurysm contracted. The patient remains fit and healthy, with two small scars in the groin.
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Fig. 4.1, cont’d
Conceptual Overview • Relationship to Other Regions
Fig. 4.13, cont’d
Fig. 4.15, cont’d
Fig. 4.47, cont’d.
Fig. 4.50, cont’d
In the clinic—cont’d
In the clinic—cont’d
In the clinic—cont’d
In the clinic—cont’d
In the clinic—cont’d
In the clinic—cont’d
In the clinic—cont’d
In the clinic—cont’d
In the clinic—cont’d
In the clinic—cont’d
Surface Anatomy • How to Find the Superficial Inguinal Ring
Surface Anatomy • Visualizing Structures at the LI Vertebral Level
Surface Anatomy • Using Abdominal Quadrants to Locate Major Viscera
Surface Anatomy • Where to Find the Spleen
The pelvis and perineum are interrelated regions associated with the pelvic bones and terminal parts of the vertebral column. The pelvis is divided into two regions: