Population
Forty-five patients, for whom a diagnosis of unilateral proximal external iliac endofibrosis was suspected between June 2008 and December 2012, underwent an aorto-ilio-femoral arteriography, according to the same protocol. They were free of any atheromatous cardiovascular diseases or cardiovascular risk factor.
The measurements were performed on the left side in 33 patients, and on the right side in 10 patients
Five patients were excluded for our study because of lack of usable images, data or of too many physiological angulations of the artery. Three patients were excluded because they couldn’t flex the hip.
Thirty-seven patients were included for study: 31 men, 6 women with a mean age of 44 +/- 11 (range 29-69 years).
Radiological protocol
For all patients, both sides were studied, to compare right and left.
Using Seldinger technique, a 0.035 hydrophilic guidewire was introduced in the contralateral femoral artery. A 5 F multiperforated angiographic catheter was guided by a crossover procedure, in the origin of the common iliac artery (CIA) on the side to be studied, for unilateral injection.
Fluoroscopic images in neutral position of the hip joint were obtained in anteroposterior and lateral projections (30°) of the patient. Then, for the search of arterial length excess, the patients were requested to flex the hip at 90°, to be able to have images in hip flexion with lateral projection.
Concerning neutral positions, only anteroposterior projections were used because of the low resolution of lateral projections images.
Measurement technique
From the digital images obtained, several points and data were measured.
Three vascular and ligament reference points were chosen to measure the location of the folding point (figure 1):
- the bifurcation of the CIA to the departure of the extern iliac artery (A),
- the EIA to the radiological crossing line of the inguinal ligament on the ilio-femoral arterial axis (B). This line connected the anterior superior iliac spine to the pubic spine. It was traced on the anteroposterior incidence radiographs.
- the inguinal ligament to the femoral bifurcation (C).
The length of the EIA (distance A-B) was measured in the neutral position on the anteroposterior X-ray. In neutral position, it was noted if there was an arterial angulation, by excess of arterial length. It was measured in degrees, relative to the main axis of the ship.
During hip flexion, the point of arterial flexion (point D) was determined on the ilio-femoral arterial axis. Distances AD, DB, and DC, respectively representing the distance of the ilio-femoral flexion point from the origin of the EIA, from the inguinal ligament, and from the ipsilateral femoral bifurcation, were measured (Fig 2).
The length measurements were taken according to the 3 reference points on the ilio-femoral axis. The measurements in pixels are then converted into mm, from the measurement of the diameter of the intravascular probe of 5F (1.66mm).
The different angulations in extension were also measured because of their presence in several patients (Fig 3).
After femoral access, a marked catheter was advanced into the contralateral proximal common iliac artery, and an oblique image was taken, in 90° hip flexion, using an selective injection. The arterial folding point was determined only on the side without catheter.
On the oblique image, lines parallel to the central arterial line were drawn above and below the folding point, and the angle formed by the two lines was bisected. The arterial folding point was determined as the point where the line bisecting the angle.
Statistical analysis
Mean and standard deviation were calculated for each measurement. Spearman correlation analysis was used to determine the correlation coefficient between the patient’s age and the distance from the folding point to the femoral bifurcation. A second correlation analysis was made between the total length of the ilio-femoral axis and the location of the folding point.