1163. Novel Rodent Model for Simulation of Sylvian Fissure Dissection and Cerebrovascular Bypass Under Subarachnoid Hemorrhage Conditions

Authors: Avital Perry, MD; Christopher Graffeo, MD; Lucas Carlstrom, MD, PhD; William Anding; Michael Link, MD; Leonardo Rangel-Castilla, MD (Rochester, MN)

Introduction: Sylvian fissure dissection following subarachnoid hemorrhage (SAH) is a challenging but fundamental skill in microneurosurgery, and one that has become increasingly difficult to develop during residency, given the overarching management trends. We describe a novel rodent model for simulation of Sylvian fissure dissection and cerebrovascular bypass under SAH conditions. Methods: A standardized microvascular anastomosis model using rat femoral arteries and veins was used for the experimental framework. In the experimental protocol, following exposure and skeletonization of the vessels, extensive, superficial (1-2mm) soft tissue debridement was conducted, followed by wound closure and delayed re-exploration at intervals of 7, 14, and 28 days. Two resident subjects dissected 1 rat each per time point (total n=6 rats), completing vessel skeletonization followed by end-to-end artery/vein anastomoses. Videos were reviewed post-procedure to assess scar score and relative difficulty of dissection by blinded raters using 4-point Likert scales. Results: At all time points, vessels were markedly invested in friable scar, and exposure was subjectively assessed as a reasonable surrogate for Sylvian fissure dissection under SAH conditions. Scar score and relative difficulty of dissection both indicated 14 days as the most challenging time point. Conclusion: Our experimental model of femoral vessel skeletonization, circumferential superficial soft tissue injury, and delayed re-exploration provides a novel approximation of Sylvian fissure dissection and cerebrovascular bypass under SAH conditions. The optimal re-exploration interval appears to be 7-14 days. To our knowledge, this is the first model of SAH simulation for microsurgical training, particularly in a live animal system.