External grooving on a catheter traps microorganisms nurtured by mucus in a patient's body. The grooving also traps contaminating debris, originating outside the body, that migrates into the body along the catheter exterior. Energy, which may be a propagating vibration or electrical energy or a radioactive...http://www.google.co.uk/patents/US4906238?utm_source=gb-gplus-sharePatent US4906238 - Exterior antimigration refinements for self-cleaning indwelling therapeutic articles
