RESUMO
Enhancing the technology of bone-anchored limb prosthetics, we present a modified porcine model for developing an infection-free integration between the skin and a percutaneous bone implant. The deeply porous Skin and Bone Integrated Pylon (SBIP) presented an infection-free skin-implant interface both after implantation into the dorsum and after implantation into the residuum after below-knee amputation. However, deep ingrowth of skin into the porous cladding of the SBIP was achieved better in the dorsal procedure, while implantation to the residuum sometimes developed a stoma, probably due to the high mobility of the skin and soft tissues in the pig's thigh. Uncontrolled high skin mobility during the first week after implantation constituted a limitation for the porcine animal model, which we tried to address in the current study. As our previous studies showed that casting of the leg residuum did not sufficiently limit the skin's movement around the implant, we tested a modified protocol of the implantation, which included injection of botulinum toxin into the thigh muscles. During the course of the study, we identified proper botulinum toxin componentry, dosage, and the period after injections to achieve a maximal effect of immobilization of the muscles affecting skin movements. To verify the immobilization, we used kinetic data on the asymmetry of loading during gait with the Strideway System, Tekscan, Inc., Boston, MA, USA. We found that injections in the four muscles of the distal thigh of the left hind leg with MYOBLOC® (rimabotulinumtoxinB; 5,000 units/muscle) were sufficient to provide noticeable immobilization by the fourth week after the procedure. This conclusion was made based on the analysis of the dynamics of asymmetry in vertical ground reactions on the injected (left hind) and uninvolved (right hind) legs during gait over an instrumented walkway.
RESUMO
PURPOSE: To compare the degree of hemolysis generated during use of the ultrasound-based OmniSonics OmniWave Endovascular System and the Possis AngioJet connected to an Xpeedior-6 catheter. MATERIALS AND METHODS: Twelve 64-145-kg Yorkshire pigs were used as the model because their weight, blood volume, and vessel diameters are comparable to that of adult humans. Six pigs were treated with the OmniWave and six with the AngioJet; half of the pigs in each group were treated in the contralateral iliofemoral arteries and half in the ipsilateral iliofemoral veins. Devices were activated for 10 minutes in patent vessels to represent a worst-case scenario for hemolysis generation. Plasma-free hemoglobin (PfHgb) levels, red blood cell counts, white blood cell (WBC) counts, and platelet counts were measured before and after the procedure, and PfHgb levels were measured every 2 minutes during treatment. RESULTS: The OmniWave generated significantly lower PfHgb levels than the AngioJet (average, 228 vs 1,367 mg/dL; P < .001). The location of activation (arterial vs venous) had no significant effect (P = .575). Compared with OmniWave use, AngioJet use was associated with significantly greater changes from pre- to posttreatment values in WBCs (P = .002), platelets (P = .004), and creatinine (P = .002). AngioJet use was associated with a significant postprocedure decrease in the WBC count (mean, -8,000/microl; 95% confidence interval [CI]: -3,830, -12,170; P = .004) and platelet count (mean, -72,000; 95% CI: -25,000, -120,000; P = .011). With the OmniWave device there were no significant differences between pre- and posttreatment WBC count (P = .127), platelet count (P = .493), and creatinine level (P = .317). CONCLUSIONS: The OmniWave generated approximately one-sixth of the hemolysis the AngioJet created. In addition, animals treated with the AngioJet exhibited a decrease in WBC and platelet counts.