Impact of a nickel-reduced stainless steel implant on striated muscle microcirculation: A comparative in vivo study

The impairment of skeletal muscle microcirculation by a biomaterial may hav e profound consequences. With moderately good physical and corrosion charac teristics, implant-quality stainless steel is particularly popular in ortho pedic surgery. However, due to the presence of a considerable amount of nic kel in the alloy, concern has been voiced in respect to local tissue respon ses. More recently a stainless steel alloy with a significant reduction of nickel has become commercially available. We, therefore, studied bi vivo nu tritive perfusion and leukocytic response of striated muscle to this nickel -reduced alloy, and compared these results with those of the materials conv entional stainless steel and titanium. Using the hamster dorsal skinfold ch amber preparation and intravital microscopy, we could demonstrate that redu ction of the nickel quantity in a stainless steel implant has a positive ef fect on local microvascular parameters. Although the implantation of a conv entional stainless steel sample led to a distinct and persistent activation of leukocytes combined with disruption of the microvascular endothelial in tegrity, marked leukocyte extravasation, and considerable venular dilation, animals with a nickel-reduced stainless steel implant showed only a modera te increase of these parameters, with a clear tendency of recuperation. Tit anium implants merely caused a transient increase of leukocyte-endothelial cell interaction within the first 120 min, and no significant change in mac romolecular leakage, leukocyte extravasation, or venular diameter. Pending biomechanical and corrosion testing, nickel-reduced stainless steel may be a viable alternative to conventional implant-quality stainless steel for bi omedical applications. Concerning tolerance by the local vascular system, t itanium currently remains unsurpassed, (C) 2001 John Wiley & Sons, Inc.