Contralateral Limb Cannulation Using Intra-Operative Positioning SystemTechnology in Endovascular Aneurysm Repair

Background:

The current standard of care for abdominal aortic aneurysm (AAA) is endovascular aneurysm repair (EVAR) which has been suggested as the treatment of choice by both European and American guidelines . Although short-term results are favorable for EVAR compared to open surgery, one of the major drawbacks to this shift is the need for fluoroscopy and contrast dyes to visualise endovascular devices. The contrast dyes used during these procedures can induce renal failure in patients with preexisting renal dysfunction. Meanwhile, the use of fluoroscopy exposes both patients and caregivers to harmful ionizing radiation. Because of the harmful effects of radiation, recent radiation protection guidelines strongly recommend as low as reasonably achievable (ALARA) principle.

In response to these challenges, Centerline Biomedical (Cleveland, Ohio, USA) has developed a proprietary electromagnetic tracking and positioning system called the Intra-Operative Positioning System (IOPS). This medical device provides surgeons with 3D visualization for increased surgical precision while reducing the use of contrast dye and radiation exposure for patients and healthcare professionals alike. IOPS provides 3D electromagnetic navigation of interventional devices as an adjunct to fluoroscopy. Image guidance is provided using 3D maps of the vasculature, generated from thin-slice contrast-enhanced preoperative computerised tomography angiography (CTA). At the start of the procedure, a self-adhesive sterile fiducial tracking pad is attached to the patient's lumbar region, and the angiography system is used to perform a non-contrast-enhanced cone-beam CT scan. The cone beam CT volume is then loaded onto the IOPS cart and manually aligned with the preoperative CT volume. This work can be performed in parallel with achieving vascular access, with minimal effects on the procedure time. During the intervention, the IOPS devices can be visualized with on-screen image guidance. The console is operated by a technician under a physician's instruction. The IOPS guidewires and catheters can be used together or combined with off-the-shelf 0.035-inch catheters and guidewires, as needed. This technology has been used by other centres for visceral and renal cannulation during complex aortic aneurysm procedures.

Previously there have been publications on the use of Fiber Optic Real Shape (FORS) Technology with both complex and standard endovascular aneurysm repair (EVAR) showing the potential benefit of this technology in procedural time and radiation reduction. However, the need for additional radiation-reducing navigation techniques is high, with the ultimate goal of performing endovascular procedures without radiation at all.

This study aims to describe the influence of IOPS technology on radiation exposure during cannulation of the contralateral limb (CL) during standard EVAR.