A urethral false passage, known medically as via falsa, is an unintended channel or tear created in the wall of the urethra. It occurs when an instrument, such as a urinary catheter or cystoscope, deviates from the natural path of the urinary tract. Instead of passing smoothly into the bladder, the tip punctures the lining and tunnels into the surrounding spongy tissue. The creation of a false passage prevents the correct placement of the instrument and can lead to significant pain and potential long-term damage.
What is a Urethral False Passage and How Does It Form?
The urethra is a delicate tube lined with a mucous membrane and surrounded by vascular spongy tissue. A false passage forms when mechanical force is applied to the urethral wall, causing the instrument to perforate this lining. The instrument then travels in a new, abnormal path alongside the true urethral channel, creating a pocket or blind-ending tract within the tissue.
This injury is most commonly caused by traumatic instrumentation, such as a difficult or forced attempt at inserting a urinary catheter. The risk increases significantly when a patient has a pre-existing condition that narrows the urethra. Urethral strictures present a physical obstruction that can deflect the instrument tip.
Men with an enlarged prostate may also experience difficulty during catheterization, particularly where the urethra passes through the prostate gland. Repeated attempts at insertion, especially without proper lubrication or technique, increase the likelihood of the catheter tip snagging and tearing the tissue.
Recognizing the Immediate Signs
The onset of a false passage is typically marked by immediate and observable signs. The patient will often report acute pain and significant discomfort at the time of the injury.
A physical sign of the trauma is the presence of blood, which may be visible at the urethral opening (meatus). During the procedure, the most telling clinical observation is the inability to smoothly advance the instrument into the bladder. The instrument may stop abruptly, or it may feel as though it is traveling into a pocket rather than continuing its expected course.
In many cases, the instrument may be inserted to its full length, but no urine will drain because the tip is lodged in the false passage instead of the bladder. If there is any suspicion of a false passage, any further attempts at catheterization must immediately cease to prevent worsening the tear.
Diagnosis and Initial Clinical Response
Confirming the diagnosis of a false passage often requires specialized imaging techniques. A common method is a retrograde urethrogram, where a contrast dye is injected into the urethra and X-rays are taken. This imaging may reveal two parallel tracts: the true urethra and the abnormal false passage.
Direct visualization of the injury is sometimes necessary using a cystoscope, a thin, lighted instrument inserted into the urethra. This allows the medical professional to accurately locate the tear and assess the extent of the damage. Once the injury is confirmed, the immediate treatment priority is to ensure proper drainage of the bladder while allowing the urethral wall to heal.
Management involves diverting the urine away from the injury site. A small indwelling catheter may be carefully guided past the false passage and into the bladder, sometimes requiring endoscopic assistance. If placing a urethral catheter is impossible, a suprapubic catheter is surgically placed directly into the bladder through the lower abdominal wall. The temporary catheter is typically left in place for several weeks.
Healing and Preventing Future Complications
While the acute injury heals, the body’s natural response is to form scar tissue, which presents the most significant long-term risk. The formation of this scar tissue can lead to a urethral stricture.
The temporary indwelling catheter acts as a stent, holding the urethral walls in their correct alignment while the tissue re-epithelializes. Preventing recurrence relies on meticulous technique. Medical professionals must employ gentle, non-forceful catheterization methods, especially when encountering resistance.
Patients who perform intermittent self-catheterization are advised to use well-lubricated or hydrophilic catheters to reduce friction and trauma. In cases where instrumentation is difficult due to underlying conditions, specialized instruments, such as a Coude-tip catheter, may be used. Avoiding blind attempts and seeking specialist consultation immediately upon encountering resistance are the most effective strategies for prevention.