NON SUTURE CUFF TECHNIQUES - A NOVEL REVASCULARIZATION APPROACH FOR RODENT COMPOSITE TISSUE ALLOTRANSPLANTATION MODELS

Robert Sucher^1,2,3, Cheng-Hung Lin^1,3, Barbara Kern^2,3, Xin Xiao Zheng¹, Stefan Schneeberger^1,2,3, W.P. Andrew Lee^1,3, Gerald Brandacher^1,2,3.

¹Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA; ²Department of Visceral, Transplant and Thoracic Surgery, D. Swarovski Research Laboratory, Innsbruck Medical University, Innsbruck, Austria; ³Department of Plastic and Reconstructive Surgery, UPMC, Pittsburgh, PA, USA.

Background: The development of microsurgical techniques has recently facilitated the establishment of vascularized composite tissue transplants in rodents. However, current models utilize a technically highly demanding and time consuming micro-vascular suture technique. Our objective was to develop a new simplified procedure using a cuff technique for revascularization to minimize operating time and yet maximize success rate.

Methods: Balb/c hindlimbs were transplanted orthotopically (mORT) or heterotopically (mHET) to Balb/c or C57BL/6 recipients. ORT: Vascular anastomosis were completed by pulling the recipient femoral vessels over the respective venous and arterial cuffed donor vessels and fixed with a 10-0-ligature thereby facilitating a non-suture technique. The sciatic nerve was approximated end-to-end. HET/cervical: donor vessels of a reduced size osteomyocutaneous hindlimb CTA were anastomosed to the recipient common carotid artery and external jugular vein without nerve approximation. In Lewis rats syngeneic orthotopic hindlimb transplants were performed using either the conventional suture (rsORT) - or the cuff technique (rcORT).

Results: All procedures resulted in a high success rate (mHET: 90%, mORT: 62%, rsORT: 100%, rcORT: 90%). Complications in terms of bleeding and thrombosis were higher in the mORT group as compared to mHET, rcORT and rs ORT groups respectively. All syngeneic grafts survived long term (>100 days). FK506 (2 mg/kg) significantly prolonged graft survival (87±22 days) when compared with untreated controls (6±1 day). Functional evaluation (video gait kinematics/ CatWalk analysis) of mORT and rcORT grafts revealed specific differences of gait parameters when compared with non-transplanted controls.

Conclusion: Using a cuff technique in various rodent CTA models is technically and microsurgically feasible and results in excellent graft survival. Major advantages are short ischemia time, lack of vascular complications, and a relatively short operation time. This approach also allows for the first time to study both nerve regeneration and basic immunology in mouse models of CTA.