LAUSR

BACKGROUND Because endovascular abdominal aortic repair (EVAR) lowers the lumbar arterial blood flow, we hypothesized that the volume of the psoas muscle decreases after surgery. When internal iliac artery (IIA) embolization is performed, the lumbar arterial blood flow further decreases; therefore, we also hypothesized that the decrease in the volume of the psoas muscle becomes more significant. This study was performed to assess the volume change in the psoas muscle after EVAR. METHODS Fifty-three consecutive patients who underwent EVAR from January 2016 to December 2016 were included. The psoas muscle volume was measured by preoperative and postoperative computed tomography (CT). Postoperative CT scans were performed 6 to 12 months after EVAR. Axial CT images with a 2-mm slice thickness were used to measure the psoas muscle volume. Data were transferred to a three-dimensional workstation, and the psoas muscle volume was measured. RESULTS In the EVAR group, the volume of the psoas muscle decreased by an average of 5.8 ml (4.6%) from 114.8 ± 32.0 ml preoperatively to 109.0 ± 30.3 ml postoperatively (p < 0.01). There was a significant difference in the change in the psoas muscle volume between patients with and without IIA embolization (embolization group: preoperative, 118.1 ± 31.0 ml; postoperative, 107.5 ± 29.2 ml; mean volume change rate, -8.8%; non-embolization group: preoperative, 114.0 ± 32.3 ml; postoperative, 109.4 ± 30.7 ml; mean volume change rate, -3.6%; p < 0.05). CONCLUSIONS The psoas muscle volume is reduced with EVAR. Moreover, when the IIA is embolized, the psoas muscle volume is further reduced.