Percutaneous implants

The currently available percutaneously implanted pumps offer short term ventricular support only. They have been mostly used in acute cardiogenic shock to provide acute hemodynamic stability before another definitive therapy like revascularization, surgical LVAD, or transplantation. Following is a description of the currently available percuatneous LVADs. 

It is often demanded that the surface of polymeric biomaterials should exhibit permanent tenacious adhesion to soft connective and dermal tissues. However, conventional non-porous, polymeric materials will be encapsulated by a fibrous membrane generated de novo by surrounding fibroblasts, when subcutaneously implanted into the living body in contact with soft connective tissues. This is a typical foreign body reaction of the living system to isolate foreign materials from the host inside the body. On the other hand, it should be noted that the small gap present between a percutaneously-implanted device and the surrounding tissue provides a possible route for bacterial infection because of the lack of microscopic adhesion at the interface. 

Fig. 18. Bacterial infection observed during percutaneous implantation of silicone devices into rabbits (O) non-treated and ( ) collagen-immobilized...

The intrathecal route is more invasive than i.v, i.m. or s.c routes. Both percutaneously implanted catheters and subcutaneously implantable pumps have heen used to reduce the risk of infection on repeated puncture. 

Grube E, Laborde JC, Gerckens U, etal. Percutaneous implantation of the CoreValve self-expanding valve prosthesis in high-risk patients with aortic valve disease the Siegburg first-in-man study. Circulation 2006 Oct 10 114(15) 1616-24. 

In-Vivo Percutaneous Implant Experiment. The principle of percutaneous attachment has extensive application in many biomedical areas, including the attachment of dental and orthopedic prostheses directly to skeletal structures, external attachment for cardiac pacer leads, neuromuscular electrodes, energy transmission to artificial heart and for hemodialysis. Several attempts to solve the problem of fixation and stabilization of percutaneous implants(19) have been made. Failures were also attributed to the inability of the soft tissue interface to form an anatomic seal and a barrier to bacteria. In the current studies, the effect of pore size on soft tissue ingrowth and attachment to porous polyurethane (PU) surface and the effect of the flange to stem ratio and biomechanical compliance on the fixation and stabilization of the percutaneous devices have been investigated.(20)... 

A series of percutaneous implant devices with three stem/flange ratios (1 1, 1 2 and 1 4) was fabricated from three materials (Dacron velour - silicone, porous PU and porous metal). The implants were totally porous (coarse, 150-250 ym) with 1.5 mm diameter holes drilled throughout the device. Figure 6 shows the mold and the polyurethane percutaneous devices with three stem/ flange ratios and 1.5 mm diameter drilled holes. 

Figure 6. Porous polyurethane percutaneous implantable devices and molds.

Figure 9. Sites for the percutaneous implantation of the porous devices in the dorsum and subcutaneous implantation of discs in thigh and belly.

Conclusions. Results from the biocompatibility studies in rabbit supratellar bursa, measurement of hydrophilic properties, lubrication and wear in-vitro studies, determination of viscoelastic properties, measurement of damping coefficient and impact test, total elbow joint replacement design and in-vivo percutaneous implant experiment, all indicate that this series of polyurethanes is an excellent candidate biomaterial for the prosthetic replacement of articular cartilage, artificial joint prostheses and percutaneous implantable devices. 

Wong, E.W. Bennington, A.G. A Percutaneous Implant Using a Porous Metal Surface Coating for Adhesions to Bone and a Velour Covering for Soft Tissue Attachment, Results of Trials in Pigs, J. Biomed. Mat. Res., 1977, 11, 883. ... 

A Percutaneous Implant Experiment Using Porous Coatings for Soft Tissue Attachment A Preliminary Report, accepted for presentation at International Congress of Implantology and Biomaterials in Stomatology, June 9-12, 1980, in Kyoto, Japan. 

Artificial skin is another example of a percutaneous implant, and the problems are similar to those described above. Important for this apphcation is a material which can adhere to a large (burned) surface and thus prevent the loss of fluids, electrolytes, and other biomolecules until the wound has healed. 

B. Cheroudi, T.R.L. Gould, D.M. Brunette, A light and electron microscopic study of the effects of surface topography on the behavior of cells attached to titanium-coated percutaneous implants, J. Biomed. Mater. Res. 25 (1991) 387. 

Figure 11. Infection rate for polyethylene sponge percutaneously implanted in rabbits. (OX without collagen immobilization ( ), with collagen immobilization. Source Reproduced with permission from reference 18. Copyright 1988 American Chemical Society.

Silver has been used as a bacteriostatic agent in percutaneous implants and sutures. Again, the effect was increased when an electrical current was applied. Silver-coated sutures were found to be effective against a broad range of bacteria [28],... 

Fig. 4.66 A Stylized Ulustratioii of axillary venipuncture using tbe guidewire as a landmark. B Radiograph of needle accessing the axillary vein using the guidewire as a landmark. (Shefer A, Lewis BS, Gang ES. The retropectoral transaxillary permanent pacemaker description of a technique for percutaneous implantation of an invisihle device. Pacing Chn Electrophysiol 1996 19(llPt 1) 1646-1651, with permission.)...

Shefer A, Lewis SB, Gang ES. The retropectoral transaxillary permanent pacemaker description of a technique for percutaneous implantation of an invisible device. PACE 1996 16 1646. 

Park, S., Lee, S.J., Lee, M., Lee, M.S., Kim, G.M., Kim, M.D., Won, J.Y., Lee, D.Y., 2015. Prospective randomized trial comparing pushable coils and detachable coil during percutaneous implantation of port-catheter system for hepatic artery infusion chemotherapy. Abdominal Imaging 40, 595-600. 

P. Kreis and S. Fishman, Spinal Cord Stimulation Implantation Percutaneous Implantation Techniques, Oxford University Press, USA, 2009. 

Thalhammer C, Kirchherr AS, Uhlich F, Waigand J, Gross CM (2000) Postcatheterization pseudoaneurysms and arteriovenous fistulas repair with percutaneous implantation of endovascular covered stents. Radiology 214 127-131... 

Buellesfeld, L., Gerckens, U., and Gruhe, E., Percutaneous Implantation of the first repositionable aortic valve prosthesis in a patient with severe aortic stenosis. Catheter Cardiovasc Interv, 2008. 71(5) p. 579-84. 

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