Arteriovenous fistula and bone healing: experimental study in the rat

The incidence of fractures is greater in patients with hemodialysis than in the general population. Surgically created arteriovenous fistulas are widely used in end-stage renal failure patients for the vascular access of hemodialysis. Despite occurrence of fracture at the fistula site in the forearm, bone mineral density is similar in both arms. The effects of arteriovenous fistulas on fracture healing have not been widely studied. The goal of this study was to test the hypothesis that a fracture distal to a surgically-created arteriovenous fistula has negative effects in a rat osteotomy model. The tibial bones were fractured in a monocortical fashion bilaterally. No fixation method was used. The right side was used as control. On the left side of the rat, a side-to-side arteriovenous anastomosis was done between the common femoral vessels proximal to the fracture line under magnification with the operating microscope. Three weeks later, bone segments, including the monocortical osteotomy line, were removed and examined histopathologically. Although the gross appearance of callus formation was not different in both groups, histopathologically, there were more dead medullary bone and less cartilage cells around the osteotomy line in the bone associated with the arteriovenous fistula. But with short-term evaluation of the fracture sites after opening an arteriovenous connection proximal to the fracture site, no real difference was noted related to fracture healing.