Microsurgical Bypass Training Rat Model: Part 2-Anastomosis Configurations.

Background: Mastery of microsurgical anastomosis is key to achieving good outcomes in cerebrovascular bypass procedures. Animal models (especially rodents) provide an optimal preclinical bypass training platform. However, the existing models for practicing different anastomosis configurations have several limitations.

Objective: We sought to optimize the use of the rat's abdominal aorta and common iliac arteries (CIA) for practicing the 3 main anastomosis configurations commonly used in cerebrovascular surgery.

Methods: Thirteen male Sprague-Dawley rats underwent inhalant anesthesia. The abdominal aorta and the CIAs were exposed. The distances between the major branches of the aorta were measured to find the optimal location for an end-to-end anastomosis. Also, the feasibility of performing side-to-side and end-to-side anastomoses between the CIAs was assessed.

Results: All bypass configurations could be performed between the left renal artery and the CIA bifurcation. The longest segments of the aorta without major branches were 1) between the left renal and left iliolumbar arteries (16.9 mm ± 4.6), and 2) between the right iliolumbar artery and the aortic bifurcation (9.7 mm ± 4.7). The CIAs could be juxtaposed for an average length of 7.6 mm ± 1.3, for a side-to-side anastomosis. The left CIA could be successfully reimplanted on to the right CIA at an average distance of 9.1 mm ± 1.6 from the aortic bifurcation.

Conclusions: Our results show that rat's abdominal aorta and CIAs may be effectively used for all the anastomosis configurations used in cerebral revascularization procedures. We also provide technical nuances and anatomic descriptions to plan for practicing each bypass configuration.