Small Animal Surgery Resident University of Wisconsin-Madison Madison, Wisconsin
Orthopaedic infections are serious, debilitating conditions in companion animals that are difficult to treat. Multidrug resistant bacterial infections complicate systemic antimicrobial treatment, therefore alternative regional strategies are desirable. Antimicrobial intravenous regional limb perfusion (IVRLP) is an established strategy in horses but has not been explored in small animals. This study aimed to describe a technique for IVRLP in dogs, and to evaluate efficacy of drug delivery to target tissues in the pelvic limbs. IVRLP was performed using contrast radiography, followed by 5mg/kg amikacin in saline in the hindlimbs of 12 experimental research dogs. Antimicrobial concentration in serum, synovial fluid, and bone marrow following IVRLP was assessed. Contrast reached the terminal veins in the digital paw pads but did not extend proximal to the tourniquet. Tourniquet location and patient size impacted volume required to achieve complete intravascular distribution. Systemic amikacin plasma levels with the tourniquet in place were 3.2+/-2.25 ug/dl and increased to 11.87ug/dl (+/- 1.77) 30 min following removal. Amikacin levels were 171.99+/-202.61 ug/dl and 566.85/829.74 ug/dl in stifle synovial fluid and tibia bone marrow, respectively. Limb contrast boundaries and amikacin levels suggest IVRLP can be successfully used in the canine hindlimb. Tissue amikacin levels exceeded the minimum inhibitory concentration of common pathogens in 11/12 dogs. Further research is recommended to optimize volume recommendations for varying dog size and thoracic limbs. This study demonstrates early safety and efficacy for use of IVRLP for treatment of orthopedic infections in dogs.
