Bohart Zachary, Cassidy Charles, Merrill David, Villani Mario, Villani Rosanna, Cappabianca Leo, Pitkin Mark
Department of Orthopaedics and Physical Medicine and Rehabilitation, Tufts University School of Medicine, Boston, MA, United States.
DaVinci Biomedical Research Products, Lancaster, MA, United States.
Front Rehabil Sci. 2022 Mar;3. doi: 10.3389/fresc.2022.758238. Epub 2022 Mar 3.
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.
为了改进骨锚式肢体假肢技术，我们提出了一种改良的猪模型，用于在皮肤与经皮骨植入物之间实现无感染的整合。深度多孔的皮肤与骨整合支杆（SBIP）在植入背部以及膝下截肢后的残肢后，均呈现出无感染的皮肤-植入物界面。然而，在背部手术中，皮肤向SBIP多孔包层的深度向内生长情况更好，而植入残肢时有时会形成造口，这可能是由于猪大腿皮肤和软组织的高移动性所致。植入后第一周内不受控制的高皮肤移动性是猪动物模型的一个限制因素，我们试图在本研究中解决这一问题。由于我们之前的研究表明，对腿部残肢进行石膏固定并不能充分限制植入物周围皮肤的运动，因此我们测试了一种改良的植入方案，其中包括向大腿肌肉注射肉毒杆菌毒素。在研究过程中，我们确定了合适的肉毒杆菌毒素成分、剂量以及注射后的时间段，以实现对影响皮肤运动的肌肉的最大固定效果。为了验证固定效果，我们使用了美国马萨诸塞州波士顿Tekscan公司的Strideway系统获取的步态中负重不对称的动力学数据。我们发现，用MYOBLOC®（利美布汀毒素B；每块肌肉5000单位）对左后腿大腿远端的四块肌肉进行注射，足以在术后第四周提供明显的固定效果。这一结论是基于对在仪器化人行道上行走时注射侧（左后腿）和未注射侧（右后腿）垂直地面反应不对称动力学的分析得出的。
