The sandwich technique to treat aortoiliac aneurysms: How to size the parallel graft

Introduction

The current gold standard of treatment aortoiliac aneurysms are through endovascular aneurysm repairs which can result in occluding the internal iliac artery. An alternative that preserves internal iliac artery blood flow is the sandwich technique. This is when two covered stents of the internal and external iliac arteries are placed inside the main limb of common iliac artery stent. The complexity of such task is complicated by efficiently calculating the size of the stent grafts to ensure a proper fit.

Methods

We have developed a mathematical proof that depends on the arterial circumferences to size the three stents needed for the sandwich technique: $D\cong \left[0.68*\left(d_1+d_2\right)\right]+2$. D is the diameter of the common iliac stent, d₁ and d₂ is the diameter of the internal and external iliac artery stent. We added 2 mm to account for the thickness of stents.

Results

We have treated 10 common iliac artery aneurysms using this formula. Patients were followed up by CTA scans three, six and twelve months after the procedure. Seven of ten had complete sealing and no type III endoleaks intraoperatively. The other three had a small, limited type III endoleak at completion angiogram, that disappeared completely on the three months follow-up. At one-year follow up only one patient developed moderate claudication and erectile dysfunction.

Conclusion

ST is considered a practical and feasible approach, as it is easy to implement and can be utilized in most cases, especially in emergencies. It is also cost effective due the use of standard grafts without the need for specialized stents. Our aiming by improving this surgical technique is that we will be able to help standardize practice leading to reduced waste, maintain longer-term repair and therefore reduce complication risks.