Association Between Preoperative Gluteal Muscle Quality on CT and Buttock Claudication After EVAR With Internal Iliac Artery Embolization.

Abstract

Objective: Internal iliac artery (IIA) embolization is frequently performed during endovascular aneurysm repair (EVAR) to secure an adequate distal sealing zone or to treat iliac artery aneurysms; however, it may result in postoperative buttock claudication. This study investigated the association between preoperative gluteal muscle mass and quality assessed on noncontrast computed tomography (CT) and the risk of postoperative buttock claudication.

Methods: This was a 2-center retrospective observational study conducted across 2 institutions. A total of 116 patients who underwent EVAR with concomitant IIA embolization between May 2015 and February 2025 were included. Preoperative noncontrast CT was used to assess gluteal muscle quality, defined by CT attenuation, and muscle mass, defined by cross-sectional area (CSA), of the gluteus medius and gluteus maximus muscles. The primary outcome was newly developed postoperative buttock claudication. Logistic regression analyses were performed to identify factors associated with buttock claudication. Variables that remained significant in multivariable analysis were further evaluated using receiver operating characteristic (ROC) curve analysis.

Results: Buttock claudication occurred in 54 of 116 patients (46.6%). While CSA was not associated with buttock claudication, CT attenuation values of both the gluteus medius and gluteus maximus were significantly higher in patients who developed buttock claudication (both P < .001). In multivariable analysis, bilateral IIA embolization, gluteus medius CT attenuation, and gluteus maximus CT attenuation were independently associated with buttock claudication. Receiver operating characteristic analysis demonstrated moderate discriminatory ability, with an area under the curve of 0.764 for the gluteus medius and 0.717 for the gluteus maximus.

Conclusion: In patients undergoing EVAR with IIA embolization, preoperative gluteal muscle quality assessed by noncontrast CT was independently associated with the development of buttock claudication, whereas muscle mass was not. Preoperative assessment of gluteal muscle quality may provide complementary information for risk stratification and patient counseling. In anatomically feasible cases, it may also serve as an adjunctive factor when discussing pelvic perfusion-preserving options.Clinical ImpactButtock claudication after EVAR with internal iliac artery embolization has traditionally been explained by anatomical and technical factors. This study demonstrates that gluteal muscle quality, assessed by CT attenuation on routine preoperative noncontrast CT, is independently associated with the development of buttock claudication, whereas muscle mass was not associated with this outcome. By introducing muscle quality as a patient-related risk factor, these findings suggest that preoperative assessment of gluteal muscle quality may provide complementary information for risk stratification and patient counseling. In anatomically feasible cases, this information may also serve as an adjunctive factor when discussing pelvic perfusion-preserving options, although it should not be used as a stand-alone criterion for treatment selection. However, the broader clinical applicability of this approach requires prospective validation in independent cohorts.