Medical devices may include a tubular body including a lumen and a wire extending through the tubular body. For example, a lead includes at least one wire—a lead wire, extending through a tubular body—a lead body. The lead wire may be metallic while the lead body may be a silicone or polyurethane material. The lead body isolates the lead wires from surrounding tissue and any external environment that could compromise the lead's performance.
During use, lead wires may rub on the inner surface of the lead body due to the constant movement of the patient. Over time, the lead wires may abrade or wear on the inner surface of the lead body. In some circumstances, such wear can result in a failure of the isolation system and short-circuiting of the lead.
In another example, a rotational atherectomy catheter includes at least one wire—a drive shaft, extending through a tubular body—a catheter. The drive shaft may be a helically coiled metallic wire while the catheter may be a silicone or polyurethane material. The catheter isolates the rotating drive shaft from the surrounding tissue. A lubricant including saline may flow between the catheter and the drive shaft.
During use, where the catheter must curve to confirm to the human body, the drive shaft may be forced against the inner surface of the catheter. This force may push lubricant out from between the outer surface of the drive shaft and the inner surface of the catheter. Without lubrication, friction between the rotating drive shaft and the catheter may generate head and particles which may result in a failure of the rotational atherectomy catheter.