Proposal of renal artery's ostial projection under virtual geometric correction in infrarenal aneurysms: initial results of a pilot study.

INTRODUCTION: Endovascular aneurysm repair requires the precise deployment of the graft. In order to achieve accurate positioning, the anatomical and morphological characteristics of the aorta and its branches is mandatory. Software that perform three dimensional reformatting of multislice tomographic images, allow for the study of the whole aorto-iliac axis and the perpendicular visualization of the origin of the renal arteries. The correct length of the proximal neck can be evaluated and adequate graft fixation and sealing may be foreseen. A technique is presented, using an software, for the orthogonal correction of the position of the renal arteries in relation to the proximal neck, which may guide the radioscopic orientation intraoperatively.

METHODS: Within a multiplanar tomographic image reconstruction, virtual triangulation allows for the three dimensional orthogonal correction of the renal arteries' ostia position. The predetermined best angulations for visualization are annotated and used for the positioning of the surgical C-arm.

RESULTS/DISCUSSION: Some authors discuss that the anatomic position of the renal vessels seen on the tomographic scan can change during the surgical procedure. It is known that the renal arterys' angular positioning does not alter, even after insertion of stiff guidewires, introducers, and the endograft itself. Therefore, it is possible, using concepts of spacial geometry and orthogonal correction, to predict the ideal bidimensional intraoperative positioning of the radioscopy device in order to reproduce the optimized renal artery ostial projection, ensuring the best accuracy during endograft deployment.

CONCLUSION: As closer to the tomographic reproduction was the radioscopic correction, more careful is the visualization of the ostium of the renal artery, better is the exploitation of the lap for fixing and sealing and the endoprosthesis deployment is more accurate.