J Trauma Acute Care Surg. 2019 Mar 1; Epub ahead of print

# CT Correlation of Skeletal Landmarks and Vascular Anatomy in Civilian Adult Trauma Patients: Implications for Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA).

Eliason J, Derstine B, Horbal S, Wang N, Holcombe S, Chiu C, Ross B, Bromwell B, Morrison J, Wang S

BACKGROUND: REBOA is a valuable resuscitative adjunct in a variety of clinical settings. In resource-limited or emergency environments, REBOA may be required with delayed or absent image-guidance or verification. Catheter insertion lengths may be informed by making CT correlations of skeletal landmarks with vascular lengths.

METHODS: 2247 trauma patients with CT imaging between 2000-2015 at a single civilian tertiary care center were identified, yielding 1789 patients with adequate contrast opacification of the arterial system in the chest, abdomen, and pelvis. Individual scans were analyzed using MATLAB software, with custom high-throughput image processing algorithms applied to correlate centerline vascular anatomy with musculoskeletal landmarks. Data were analyzed using R version 3.3.

RESULTS: The median centerline distance from the skin access to the aortic bifurcation was longer by 0.3 cm on the right than on the left side. Median Aortic Zone I length was 21.6 (IQR, 20.3-22.9) cm, while Zone III was 8.7 (7.8-9.5) cm. Torso extent (TE) correlation to Zone I was much higher than for Zone III (R2 0.58 vs 0.26 (right) and 0.58 vs. 0.27 (left), p<0.001). Assuming a 4 cm balloon length, optimal fixed insertion length would be 48 cm and 28 cm for Zones I and III (Error 0.4% vs 33.3%), respectively, although out of zone placements can be reduced if adjusted for TE (Error 0% vs 26.4%).

CONCLUSIONS: CT morphometry suggests a fixed REBOA catheter insertion length of 48 cm for Zone I and 28 cm for Zone III is optimal (on average, for average-height individuals), with improved accuracy by formulaic adjustments for torso extent. High residual error for Zone III placement may require redesign of existing catheter balloon lengths or consideration of the relative risk associated with placing the balloon catheter too low or too high.