Methods and Materials
Shunt Creation
Medical grade barium-impregnated silicone catheter tubing with an outer diameter of 2.8 mm and inner diameter of 1.5 mm (Medtronic, Minneapolis, MN) were cut into 2-centimeter segments. To mimic the conical shape of hole in industrial made catheters, eight holes were punched using a 0.5 mm diameter leather punch 1.25 mm apart. Dimension used followed those seen in Medtronic catheters. The catheter was rotated 90 degrees, two times, repeating the punching process to create a total of three rows of eight holes. Excess catheter material left over after punching the holes was removed using tweezers. The final dimensions of the catheter holes were 0.5 mm outer diameter with 1 mm edge to edge separation, confirmed with confocal microscopy (Figure 5). The outer diameter was measured to ensure this method resulted in accurate dimensions after manually punching the samples. Sterilization of these samples began with a one-hour incubation in 10% bleach. Following this, a series of washes included a 30-minute incubation in ethanol followed by two 10-minute washes with double distilled cell culture water (Growcells, Irvine, CA). Phenol red (v/v 1%) (Sigma, St. Louis, MO) was added into the last wash to observe if a color change occurred, ensuring all ethanol was removed.