Coiled wire intramuscular electrodes have been used, in humans and animals, as electrodes with leads that traverse the skin since the latter half of the 1960s at Case Western Reserve University. From the beginning, everyone was favorably surprised that infections were rare and when they occurred at the skin exit site were easily controlled with topical antibiotics.
The tight cell layer plays an important role in protecting the subcutaneous area from pathogen invasion. In this vignette I am animating an experimental result that I observed in the course of one spontaneous experiment. Animal experiments carried out in the lab often involved electrodes implanted in the hind limbs or abdomen and coursing in the subcutaneous space to exit in the upper shoulder or neck region. These electrodes remained in place for months and years. At the termination of one of these experiments the subcutaneous track, of the lead section of the tissue capsule, was exposed. Two incisions were made approximately ten centimeters apart through the track, and the lead wire, to expose and gain access to the lead. When these leads are withdrawn they “corkscrew” out of the tissue capsule. In the experiment I’m describing a pool of Evans blue labeled bovine serum albumin was created at one of the capsule incision sites and the lead was withdrawn from the other site, drawing into the capsule the labeled albumin. While the labeled albumin diffused rapidly through the tissues at the pooling site the labeled albumn in the capsule track did not diffuse out over a period lasting something like an hour.