Anatomic Factors Contributing to External Iliac Artery Endofibrosis in High-Performance Athletes.

Background: External iliac artery endofibrosis (EIAE) classically presents in cyclists with intimal thickening of the affected arteries. We investigated possible anatomical predisposing factors including psoas muscle hypertrophy, arterial tortuosity, inguinal ligament compression, and arterial kinking via a case-control comparison of symptomatic and contralateral limbs.

Methods: All patients with unilateral EIAE treated surgically at our institution were reviewed. Each patient's symptomatic side was compared with their contralateral side using paired t-tests. Psoas hypertrophy was quantified by the transverse cross-sectional area (CSA) at L4, L5, and S1 vertebral levels, and inguinal ligament compression was measured as the anterior-posterior distance between the inguinal ligament and underlying bone. Tortuosity index for diseased segments and arterial kinking were measured on TeraRecon.

Results: Of 33 patients operated on for EIAE from 2004 to 2021, 27 with available imaging presented with unilateral disease, more commonly left-sided (63%). Most (96%) had external iliac involvement and 26% had ≥2 segments affected: 19% common iliac artery, 15% common femoral artery. The symptomatic limb had greater mean L5 psoas CSA (1,450 mm vs. 1,396 mm, mean difference 54 mm, P = 0.039). There were no significant differences in L4 or S1 psoas hypertrophy, tortuosity, inguinal ligament compression, or arterial kinking. 63% underwent patch angioplasty, and 85% underwent additional inguinal ligament release. 84% reported postoperative satisfaction, which was associated with a greater difference in psoas hypertrophy at L4 (P = 0.022).

Conclusions: Psoas muscle hypertrophy is most pronounced at L5 and is associated with symptomatic EIAE. Preferential hypertrophy of the affected side correlates with improved outcomes, suggesting psoas muscle hypertrophy as a marker of disease severity.