Think urethra

There are a number of different considerations when consulting with a person about which catheter they might use for intermittent self-catheterisation, and it is important to include the potential for urethral damage among these. This article explains why.
 

Anatomy and physiology

Along with the bladder, the urethra forms the lower urinary tract. It is sometimes considered to just be a tube that allows urine to leave the bladder, but the muscles and lining of the urethra both have an important role to play in ensuring that the urethra works properly. It is important that healthcare professionals consider urethral health and integrity as a vital part of continence care.  

The male urethra is between 15–22cm long, while the female urethra is only 3–5cm in length (Jones, 2025). The male urethra extends from the bladder neck, through the prostate gland and the pelvic floor, then down to the external urethral opening. The female urethra extends from the bladder neck through the pelvic floor to the external opening and shares a wall with the vagina, which is situated behind it (Figure 1).
 

Figure 1. Anatomy of the male and female urinary systems.

The lining of the urethra is made up of epithelial cells (Figure 2) which are protected from the effects of urine by the presence of mucus-secreting glands.
 

Figure 2. Transitional epithelial tissue, also known as urothelium – a highly specialised, stratified epithelial tissue lining the urinary tract.
 

Protecting the urethra

Looking at the anatomy and physiology of the urethra, it is clear how important its integrity is to patient safety and comfort. Many catheter users would say that the most important role of the urethra is in protecting against the development of urinary tract infections (UTIs) - these are often reported by patients as being the most troublesome and painful condition linked to catheterisation.
As well as reducing the chance of developing a UTI, taking steps to reduce the likelihood of damaging the lining of the urethra while catheterising can have a number of clinical benefits for the patient:

• Using catheters that have integral hydrophilic properties or a coating to make them easier to both insert and remove can help to keep the urethral lining intact. This makes it harder for bacteria to breach the protective barrier and cause infection, decrease the risk of developing UTIs.
• Ex-vivo research found that a catheter with integral hydrophilic properties needed less force to insert and remove it than catheters that use hydrophilic coatings (Burns et al, 2025).
• This study also found that catheters that use hydrophilic coatings left some of the coating within the urethra after they had been removed while the catheter with integral hydrophilic properties left no residue.
• Burns et al (2025) looked for evidence of microtrauma to the urethral lining following removal of the catheters. While all intermittent catheters studied caused some degree of damage to the urethral lining, the hydrophilic coated catheters caused more damage to the uroepithelial membrane than the catheter with integral hydrophilic properties or the uncoated catheter.
• In a previous study, Burns et al (2024) showed that the surface of coated catheters can dry out while in the urethra and then stick to the lining of the urethra. This can mean that more force is needed to remove the catheter and can damage the urethral lining when the catheter is pulled away from it. In contrast, the catheter with integral hydrophilic properties needed less force to begin removing it, which suggests that a coating-free hydrophilic surface could reduce the risk of urethral microtrauma.
• If the lining of the urethra is injured, the scar tissue that develops in response can make it harder to catheterise as this narrows the diameter of the urethra.
• A breach in the urethral lining will also disrupt the mucous membrane, which may increase the pain experienced during or after catheterising as urine comes into direct contact with the epithelial cells.
• The muscles in the urethra form the sphincters which control release of urine. If these contract, it can make insertion and removal of the catheter harder.
• The psychological effects of fearing pain on insertion and/or removal, and worry about contracting further UTIs are very real for catheter users. These can also have physical effects as they can lead the user to tense up inadvertently before inserting/removing the catheter, which can make the process harder.

 

Conclusions

Whether you are prescribing a catheter to someone for the first time, or reviewing the practice of an experienced user, take a moment to make sure that the solution that you are providing isn’t inadvertently causing unnecessary damage. This will ensure that you are providing the best possible care for all those who use intermittent self-catheterisation

References

Burns J, Pollard D, Ali A, McCoy CP, Carson L, Wylie MP (2024) Comparing an integrated amphiphilic surfactant to traditional hydrophilic coatings for the reduction of catheter-associated urethral microtrauma. ACS Omega. 9 (20):22410-22422. https://doi.org/10.1021/acsomega.4c02109

Burns J, Irwin RN, Quinn J et al (2025) An ex vivo porcine urethral model for investigating intermittent catheter-associated urethral microtrauma. Materials Design. 259:114727. https://doi.org/10.1016/j.matdes.2025.114727

Jones O (2025) The urethra. https://teachmeanatomy.info/pelvis/viscera/urethra/ (accessed 11 February 2026)