[The anatomic relationship of the umbilicus to retroperitoneal major vessels]

To study the anatomic relationship of the umbilicus to the retroperitoneal major vessels and the characteristics of such relationships among the Chinese with different body weights so as to provide a clear reference to the operator of laparoscopy.

Eighty-nine patients without pelvic disease, 57 males and 32 females who accepted digital subtraction angiography (DSA) of aorta were randomly selected and divided into 3 groups: non-obese group, overweight group, and obese group according to body mass index (BMI). All the patients lied supine with a round block of lead 1 cm in diameter located on the umbilicus. Seldinger technique was used to puncture the right femoral artery so as to conduct DSA. Using the bifurcation of the abdominal aorta as reference point the vertical projection relationships of the umbilicus to the retroperitoneal major vessels, abdominal aorta, right common iliac artery, and left common iliac artery were evaluated and the distance from the umbilicus to the aortic bifurcation was measured. The distance was regarded as positive if the umbilicus was cephalic to the aortic bifurcation and as negative if the umbilicus was caudal to the aortic bifurcation

There were 32 patients in the normal body weight group, 35 in the overweight group, and 22 in the obese group with the mean distances from the umbilicus to the aortic bifurcation of (14.8 +/- 19.7) mm, (0.04 +/- 2.5) mm, and (-12.6 +/- 15.4) mm respectively. In 50 of the 89 patients (63.9%) the location of umbilicus corresponded to the retroperitoneal major vessels, among which the umbilicus of 47 patients (94%) projected vertically to the abdominal aorta or the right common iliac, and the umbilicus of 3 patients (6%) projected vertically to the left common iliac artery. Compared to the above-mentioned 50 patients, in the other 39 patients (36.1%) the location of umbilicus did not corresponded to the retroperitoneal major vessels (P < 0.05), among which the umbilicus of 32 patients (82.1%) projected vertically to the right side of the aorta or of the right common iliac artery, and the umbilicus of 7 patients (17.9%) projected vertically to the internal side of the right iliac common artery. Along with the increase of body weight the projection of umbilicus gradually moved downward to the inferior side of the bifurcation of the abdominal artery. For example, among the male subjects, the distance were (10.4 +/- 4.0) mm, (-0.51 +/- 5.5) mm, and (-13.1 +/- 2.2) mm respectively in the normal body weight group, overweight group, and obese group (all P < 0.05), and in the females, the distance were (13.7 +/- 2.8) mm, (-0.14 +/- 4.4) mm, and (-11.5 +/- 3.2) mm respectively in the normal body weight group, overweight group, and obese group (all P < 0.05).

The location of umbilicus was more caudal with the increase of BMI. So once the retroperitoneal major vessels are injured, the incidence of aorta or the right common iliac artery is higher than that of other vessels.