The Use of Retraction Sutures in End-to-Side Microvascular Anastomosis - A Novel Technical Innovation in Experimental Rat Femoral Model with Successful Use in STA-MCA Bypass in Moya-Moya Disease.

BACKGROUND: A narrow working space, small diameters, and the tendency to collapse with clamps make cerebral microvascular anastomosis challenging. A retraction suture (RS) is a novel technique to keep the recipient vessel lumen open during the bypass.

OBJECTIVE: To provide a step-by-step overview of RS for end-to-side (ES) microvascular anastomosis on rat femoral vessels and successful use for STA-MCA bypass in Moya Moya disease (MMD) patients.

METHODS: A prospective experimental study with approval from the Institutional Animal Ethics Committee. Femoral vessels ES anastomoses were performed on Sprague Daley rats. The rat model used three types of RS (Adventitial, Luminal, and Flap-retraction sutures). An ES-interrupted anastomosis was done. The rats were observed for an average period of 16.18±5.65 days; the patency was assessed by re-exploration. The immediate patency on the STA-MCA bypasses was confirmed with intra-operative indocyanine green (ICG) angiography and micro-doppler; delayed patency with MRI and DSA after 3-6 months.

RESULTS: In the rat model, 45 anastomoses were performed, 15 each using the three subtypes. The immediate patency was 100%. Delayed patency was 42/43 (97.67%), and two rats died during observation. In the clinical series, 59 STA-MCA bypasses were done in 44 patients (average age -18.14±11.09 years) using RS. The follow-up imaging was available for 41/59 patients. Both immediate and delayed patency (41/41 at six months) was 100%.

CONCLUSION: The RS allows continuous visualization of the vessel lumen, reduces the handling of intimal edges, and avoids incorporating the back wall in sutures; thus improving anastomosis patency.