Most people with caudal regression syndrome (CRS) cannot urinate on their own the way the body normally would. Because the condition affects the lowest part of the spine, the nerves that tell the bladder when to squeeze and the sphincter when to relax are missing or underdeveloped. The result is a neurogenic bladder, meaning the bladder either can’t contract strongly enough to push urine out, can’t sense when it’s full, or both. How someone with CRS actually empties their bladder depends on the severity of their nerve damage and which management approach works best for their body.
Why the Bladder Doesn’t Work Normally
Bladder control depends on a coordinated signal loop between the brain, the lower spinal cord, and the muscles of the bladder and pelvic floor. In CRS, the sacral spine (the bony segments at the base of the back) is partially or completely absent. The sacral nerves that run through this area are the ones responsible for telling the bladder wall to contract and the urethral sphincter to open. Without those signals, the bladder may sit full without triggering any urge to go, or it may spasm unpredictably, causing leakage. Some people retain partial nerve function and have a weak, incomplete stream. Others have no voluntary control at all.
The specific pattern varies. Some people have a bladder that stays relaxed and overfills, stretching out over time. Others have a small, stiff bladder that holds very little and generates high internal pressure. Both patterns create real problems: the overfull bladder risks infections and overflow leaking, while the high-pressure bladder can force urine backward toward the kidneys, a condition called vesicoureteral reflux. That reflux, combined with frequent urinary tract infections, can damage kidney function over time if it isn’t managed.
Intermittent Catheterization: The Most Common Method
The primary way most people with CRS empty their bladders is through clean intermittent catheterization. This means inserting a thin, flexible tube (catheter) through the urethra and into the bladder on a schedule throughout the day. The urine drains through the tube into a toilet or collection bag, and then the catheter is removed. It sounds invasive, but for many people it becomes a quick, routine part of the day, similar to brushing teeth.
When catheterization is the main method of bladder emptying, it’s typically done every four hours during the day and every six hours overnight. Keeping to this schedule matters because urine sitting in the bladder for too long promotes bacterial growth and increases infection risk. The catheters themselves come in a range of styles: some are plain plastic or silicone, others come pre-lubricated or coated with a slippery hydrophilic surface that activates with water. Many people try several types before finding one that’s comfortable and easy to use.
Catheter size differs by anatomy. Males typically use a size 14 French gauge catheter, about 20 cm long to match the longer male urethra. Females usually use a 12 or 14 French gauge catheter, and because the female urethra is only about 5 cm long, shorter catheters (as short as 9 cm) are available. Children with CRS often learn to catheterize themselves as they get older, which gives them a level of independence that’s important for everyday life, school, and social situations.
The Mitrofanoff Procedure: A Surgical Alternative
For some people, catheterizing through the urethra is painful, difficult, or impractical. Boys can experience discomfort from repeated urethral catheterization. Girls, especially those who use wheelchairs, may find it physically difficult to position themselves on a toilet to insert a catheter. In these cases, a surgical option called a Mitrofanoff procedure can change the way catheterization works entirely.
The surgery uses the appendix to build a new, small channel connecting the bladder to a tiny opening (stoma) on the belly, usually at or near the belly button. After healing, the person catheterizes through this abdominal opening instead of the urethra. The catheter slides into the stoma, drains the bladder, and comes out. Because the stoma is on the front of the body, it’s accessible from a wheelchair, a bed, or any seated position. Children who have this procedure can empty their bladders independently without diapers and without transferring to a toilet, which is a significant quality-of-life improvement.
Bladder Augmentation for Small or High-Pressure Bladders
Some people with CRS have a bladder that’s too small or too stiff to store a reasonable amount of urine safely. When the bladder can’t expand properly, pressure builds up inside it, and that pressure can push urine back up toward the kidneys. If medications and catheterization alone aren’t enough to protect the kidneys or keep the person dry between catheterizations, a surgery called bladder augmentation (augmentation cystoplasty) may be recommended.
In this procedure, a piece of intestinal tissue is used to enlarge the bladder, giving it more room to fill at lower pressure. Studies in children and adolescents with neurogenic bladder show that augmentation improves bladder capacity, reduces internal bladder pressure, and decreases incontinence. After augmentation, most people still catheterize to empty, but the larger, more compliant bladder can hold urine longer and more safely between catheterizations. A Mitrofanoff channel is often created at the same time, so the person catheterizes through their abdomen.
Medications That Help the Bladder Behave
Alongside catheterization, many people with CRS take medications that calm the bladder muscle. These drugs work by blocking the chemical signal (acetylcholine) that tells the bladder wall to contract. By quieting those involuntary contractions, the medications reduce spasms, decrease leakage between catheterizations, and allow the bladder to hold more urine at lower pressure.
Several options exist, and the choice usually depends on side effects and how well a particular drug works for the individual. The most commonly used is oxybutynin, which relaxes the bladder muscle directly in addition to blocking nerve signals. It’s available in a long-acting form taken once daily. Other options target the bladder more selectively, which can mean fewer side effects like dry mouth or constipation. These medications don’t restore normal urination on their own, but they make catheterization schedules more manageable and help protect the kidneys from high-pressure damage.
Protecting the Kidneys Long-Term
The bladder management plan for someone with CRS isn’t just about convenience or staying dry. It’s fundamentally about protecting the kidneys. When a neurogenic bladder stores urine at high pressure, or when infections happen repeatedly, urine can reflux backward into the kidneys. Over years, this causes scarring and gradual loss of kidney function. Research on patients with sacral agenesis (the bone defect at the core of CRS) has found that long-standing lower urinary tract symptoms are universal and that upper urinary tract changes, meaning damage to the kidneys and the tubes connecting them to the bladder, are common.
This is why regular monitoring is a standard part of life with CRS. Ultrasounds track kidney size and shape. Urodynamic testing, which measures pressure inside the bladder as it fills and empties, helps doctors decide whether the current management plan is keeping pressures in a safe range. Adjustments to catheterization frequency, medications, or surgical planning are all driven by these measurements. The goal is straightforward: keep bladder pressures low, keep urine draining on schedule, and catch any signs of kidney stress early.