Dolph Houben

84 CHAPTER 4 Arteriovenous (AV) bundle patency Evaluation of the autogenous implanted AV-bundle was evaluated with Micro-CT angiography at the termination of the experiment (week 20). In the patent AV-bundle group (group 1) we found all of the implanted AV-bundles to be patent 20 weeks after transplantation. Complications Observed complications of the experiment were categorized as either minor or major. Major complications were those that required surgical intervention or resulted in termination of the experiment. One pig developed uncontrollable seizures (group 2), requiring euthanasia at 6 weeks. After full veterinarian autopsy, no focus for the seizures could be found. Another animal developed an abscess 6 weeks postoperatively at the medial malleolus (group 1). Although it resolved without apparent sequelae after debridement and antibiotic treatment, a deep infection with accompanying loss of bone alignment was confirmed at 20 weeks, caused by Staphylococcus hyicus . These two major complications required exclusion of the animals from further analyses. Minor complications were defined those which resolved spontaneously or needed only medical treatment. In the first 2-4 weeks, six pigs developed a seroma in the inguinal area, which resolved spontaneously (3 in both groups). One pig developed a generalized skin rash (group 1), possibly due to an allergic reaction. We report a total of seven (7/12) minor complications and two (2/12) major complications in this study. We assessed twelve pigs for healing scores, biomechanical measurement, and bone properties, thus resulting in two groups of six pigs. Bone healing X-rays and CT-scans were evaluated for bony union on both the proximal and distal junction of the transplant using a scoring system devised for allograft healing [24] . All allotransplants showed new periosteal bone forming from both the allotransplant and native bones at both proximal and distal junction points 2 weeks following the tibial allotransplantation, serving to indicate transplant viability through the allogenic vascular pedicle (Fig. 4). Bone healing scores at the different evaluation time points did not show a statistically significant difference between the groups. A median score of 22.83 and 23.67 healing scores were found for group 1 and 2 respectively (Table 1). All proximal host-transplant interfaces (12/12) showed complete bone union 20-weeks after transplantation. Three distal host-transplant interfaces (3/12) showed incomplete distal union, two in group 1 and one in group 2. Serial radiographic evaluation showed the incorporation, remodeling and union of the allotransplant over time (Fig. 4). Insignificance in bone healing scores between the two groups indicates that the microsurgically repaired allogenic vascular pedicle, providing initial blood flow, was responsible for much of the observed bone healing and union.