Veterans Affairs

Improved urinary catheter that eliminates tissue damage

Increases patient comfort and decreases the chance of infection by lowering the risk of tissue damage and bacterial transport

Medical & Biotechnology


The catheter, yellow, is stored inside a sterile bag. The applicator tip is placed on the outside of the urethra and the catheter is inserted. During insertion, the flexible catheter folds back upon itself thereby eliminating the sliding against tissue. (Troy Carter/TechLink)

Persons with urinary retention due to spinal cord injury, multiple sclerosis, prostate enlargement, or the like use disposable urinary catheters, referred to as intermittent catheters, to void their bladder. The process of catheterization can be messy and sometimes leads to urinary tract infections.

The state of the art in urinary catheterization is to slide a flexible plastic tube up the urethra and into the bladder. The tube is often lubricated in an effort to reduce damage to the urethra due to surface abrasion caused by the sliding of the catheter against the urethral walls. Microtrauma from this sliding can be a source of urinary tract infection. The exterior surface of the catheter can also become contaminated with bacteria when sliding through the male urethral meatus as bacteria is carried up into sterile regions of the urethra and into the bladder, likewise potentially causing urinary tract infection. The process of urinary catheterization has changed relatively little with most recent developments occurring in the area of coatings, lubrication, and packaging,

To address the above problems, Eric Nickel, VA research biomedical engineer, invented a urinary catheter assembly that can be introduced into the urethra without sliding, reducing the risk of trauma to the urethral wall and transport of bacteria and other infectious agents into the urethra and bladder.

The tip of the catheter is anchored to an applicator positioned outside the urethra. Upon introduction into the urethra, the tip of the catheter begins to unfold over itself such that the former inside of the catheter becomes the outside portion pressed against the wall of the urethra. As the catheter tube is inserted, it continually folds over itself to present the inner portion of the catheter to the tissue. The process can be related to putting socks on by rolling them up the foot and leg versus pulling them on with a sliding motion.

Because the catheter does not slide up the urethra but stays in the same position relative to the tissue wall as it is deployed, a sterile environment is maintained during both application and removal and the chance of bacterial transport to the bladder is lowered. Once the catheter tube has been inserted through the urethra into the bladder, urine is voided through the catheter tube into a suitable container or pouch associated with the distal end of the tube or directly into a toilet. After voiding, the catheter tube is retracted from the urethra and the process is reversed still avoiding sliding of the catheter tube against the urethra wall.

This invention is protected by US patent 9,789,284 and four pending international patents.

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