Overview of Urinary Diversions and Neobladders
The urinary bladder, located behind the pubic bone in the lower pelvis, functions as a storage and disposal system for urine. Its structure, divided into multiple layers, and complex neurological controls allow it to fill up without involuntary contractions (unplanned muscle movements), and empty itself by contracting a muscle called the detrusor muscle while relaxing the urinary sphincters to release urine. The bladder is the most common location for cancer within the urinary system.
For certain types of bladder cancer, especially those that have invaded the muscle and in select cases where the cancer hasn’t yet invaded the muscle, a surgery called radical cystectomy is recommended. Radical cystectomy involves removing the entire bladder, some nearby lymph nodes in the pelvis, and creating a new way for the body to store and expel urine. This same surgery can also be performed for other reasons such as unmanageable chronic bladder pain or bladder dysfunction caused by injury, surgery, or radiation, which also require creating a new system for urine management.
There are two primary methods to manage urine after a cystectomy: continent and incontinent diversions. In a continent diversion, urine is stored in a newly created reservoir (made from a segment of bowel), and the person can voluntarily control when to release it, either through normal urination or using a catheter. On the other hand, an incontinent diversion allows urine to continuously drain into a bag. It does this by diverting urine into a segment of the intestine which is then rerouted to an opening on the body’s skin, known as an ostomy. These procedures can be performed using traditional open surgery or with the help of robotic surgical techniques, performed within the body (intracorporeally).
Anatomy and Physiology of Urinary Diversions and Neobladders
The urinary bladder is an organ in the pelvis that holds urine from the kidneys and excretes it through a tube called the urethra. It’s secured to the belly button by a band of tissue called the median umbilical ligament, which is left over from when we were babies. Other bands of tissue, known as the medial umbilical ligaments, link the bladder to the belly button. The lower part of the bladder is connected to the prostate gland in men.
Blood is supplied to the bladder from the internal iliac arteries, with additional sources coming from several other arteries. Veins carry blood away from the bladder and pass it back to the heart through the internal iliac veins. The bladder’s lymph vessels, which remove waste, lead to different groups of lymph nodes. These nodes can sometimes be involved in the spread of bladder cancer.
The bladder is built of four distinct layers. The inside layer, the urothelium, interacts directly with urine and is made up of three types of cells. One of these types, the umbrella cells, act as a protective barrier to stop harmful bacteria from crossing the bladder wall while also controlling the transport of salts. The urothelium layer is tightly sealed by proteins which can be targets for bacteria that cause infections.
Beneath the urothelium is the lamina propria layer, which houses connective tissue, veins, nerves, and lymphatics. The muscularis layer is beneath this and contains smooth muscle called the detrusor, which contracts to empty the bladder. The bladder has a clever design that allows it to stretch to hold urine and then contract to empty it out effectively, all while keeping the pressure low. If bladder cancer gets past the lamina propria layer, it can spread to other parts of the body through lymph vessels and blood vessels.
For severe cases of bladder cancer, doctors may recommend removing the bladder completely. Following this, surgeries can reconstruct the urinary tract, either to uphold natural control over urination or to divert urine flow. The patient’s health, abilities, and desires, as well as surgical history, will influence the type of surgery and decision of which part of the intestine to use in reconstruction.
Some segments of bowel can be used to create urinary diversions. While the small intestine and colon are most commonly used, the stomach and a part of the small intestine called the jejunum have also been used, but only occasionally. However, using bowel parts for urinary diversion can sometimes lead to metabolic changes. These can depend on things like the specific bowel segment chosen, how much surface area of the bowel is used, and how long urine stays in contact with the bowel.
Overall, the goal when creating a new bladder after the original has been removed, is to build a reservoir that can hold urine without causing harm to the organs that produce urine. This reservoir should also be able to stretch, peel away easily, and hold urine for an appropriate time to avoid severe metabolic changes. It should also be able to facilitate urination often enough for comfortable daily living.
The bowel segment chosen for urinary reconstruction is less likely to have serious metabolic consequences when it’s the small intestine. This is because a smaller piece of bowel is used, and urine doesn’t stay in the bowel for long. Finally, in some cases where the bladder has been removed, it’s not possible to position the small intestine properly in the pelvis. In these cases, a different surgical procedure is needed. Research has recently shown that the small intestine can be used even in people who have had pelvic radiation before.
While both small intestine and colon (large intestine) segments can absorb certain substances from the urine, this can sometimes lead to an acid-base imbalance in the blood, especially if urine stays in contact with the bowel for a long time. The jejunum is used less frequently for urinary diversions, as it can cause chronic dehydration due to its more absorbent lining. This segment can also cause an imbalance of certain salts in the blood and has been associated with symptoms like nausea, weakness and even seizures.
Why do People Need Urinary Diversions and Neobladders
For serious cases of bladder cancer that have spread into the muscle, a surgery called radical cystectomy is used frequently. This surgery can remove the bladder and create a new way for the body to store and release urine. This treatment has a promising success rate, with patients reportedly remaining cancer-free for 5 years in up to 76% of cases. Usually, patients undergoing this surgery can consider several urinary reconstructive options. It’s important that they understand and discuss these different choices along with their risks and benefits before going into surgery.
The type of urinary diversion used during surgery really depends on both the specifics of the patient’s disease and their unique characteristics. Some patients may prefer an option called an orthotopic neobladder. However, this requires being able to go to the bathroom at specific times after surgery and possibly needing intermittent self-catheterization. Patients considering this option also need to understand that the way they normally go to the bathroom will change, including using a method called Valsalva voiding. There’s also the chance of experiencing incontinence, or leakage, during the day or night after a neobladder is created.
If a patient undergoes an ileal conduit, one of the methods of urinary diversion, they should be aware and capable of taking care of their ostomy (an opening in the body created during surgery) and appliance. For patients considering an alternative method of urine storage and release, known as continent cutaneous urinary diversion, they must keep in mind that this method relies on frequent and regular self-catheterization – typically 4 to 6 times a day.
When a Person Should Avoid Urinary Diversions and Neobladders
While age is not a reason to avoid creating a new bladder (known as neobladder reconstruction), older people should be aware that recovery might be slower and they may experience greater risk of nighttime accidents. A different method, known as an ileal conduit, is simpler and can result in less surgery time and less manipulation of the bowels. This option could be a better fit for older or frailer patients because it can lead to less surgical complications in the short term.
Those with cognitive issues, degenerative nerve diseases, or frailty should know that continent diversions (a type of surgery that reroutes urine to a location outside the body) require more physical agility and focus. These patients might be better served by an ileal conduit, as they may not have the necessary support from family, caregivers, visiting nurses, or long-term care facilities.
About 10% of men and up to half of women may need to use a tube intermittently to completely empty their new bladder. Thus, limited hand control and reluctance to perform self-catheterization are reasons not to create a neobladder. Severe urethral stricture disease (narrowing of the urethra) is also a reason against an orthotopic neobladder (a new bladder that discharges urine through the urethra). Patients with significant pre-existing urinary incontinence may be better served with an ileal conduit or continent cutaneous diversion, rather than an orthotopic neobladder.
In cases where cancer has affected the urethra, a neobladder is not advised due to increased risk of cancer recurrence in the urethra. Similarly, disease outside the bladder and plans for additional radiation therapy also stand against the creation of a new bladder.
Historically, patients who underwent previous pelvic radiation therapy have been advised against neobladder surgery, owing to the increased risk of complications and incontinence. These patients might therefore benefit more from an ileal conduit or continent cutaneous urinary diversion.
Finally, patients with long-standing kidney or liver disease should not have neobladder surgery. Chronic metabolic acidosis (a condition where there’s too much acid in the body) can lead to worsening of kidney disease. A minimum kidney function, measured by creatinine clearance, is needed for continent diversions. Normal liver function is also required to manage the reabsorption of ammonium in new bladders, so liver disease is also a condition preventing a neobladder surgery.
Preparing for Urinary Diversions and Neobladders
Before having surgery to divert urine flow, it’s essential for doctors to know about a patient’s past medical and surgical issues. They will need to know about any former abdominal surgeries or any past exposure to radiation that might have affected the intestines or bladder. This information is critical in deciding on the best surgical approach. If a person has chronic bowel inflammation (like with conditions such as Crohn’s disease), treating doctors might need to rethink using the large intestine for the surgery. To be on the safe side, doctors will have to perform a colonoscopy (a procedure to examine the inside of the large intestine) before using the colon in the surgery to avoid potential issues.
Before the surgery, it’s also essential to understand what will happen during the operation and the different methods that might be used. Knowing more about the process could lead to lesser regret post-surgery, and even improve overall well-being after the operation. Specialists like surgeons, physicians, and enterostomal therapists (who helps with stoma care – an artificial opening in the body for waste removal) can provide this helpful information. For patients who have a history of smoking, advice on how to quit is also recommended. This is because quitting smoking can lead to better health outcomes after surgery.
One aspect that is often overlooked but extremely important is nutrition. Research shows that a patient’s nutritional status before surgery, as indicated by albumin levels (a type of protein in blood), may affect how well they recover from the operation. Therefore, pre-surgical nutritional counseling should also be considered. Given that bladder disease often affects older individuals (around the ages of 69 to 73), they may require careful examination and medical clearance from their physicians, heart specialists, or geriatricians (doctors who specialize in aging issues) before having surgery.
In some types of urinary diversions, the small intestine is used. In these cases, there isn’t a need for bowel preparation (a process to clean the intestines before surgery). However, when the large intestine is used in the surgery, some hospitals recommend a standard bowel preparation to ensure the colon is clean and empty, mainly to lower the risk of infection.
Opioid medicines are commonly used for managing pain around the time of surgery. Some of these medicines can slow down the intestines, which can delay recovery. However, some specific types of opioids (called ‘periphery acting’) have been linked to an earlier return of bowel function after surgery. This can lead to shorter hospital stays. For this reason, the American Urological Association suggests using certain antibiotics (second- or third-generation cephalosporins) around the time of surgery to prevent infection.
How is Urinary Diversions and Neobladders performed
For some surgeries, part of the intestines, or “bowel,” is used to help redirect urine once the bladder is removed. The bowel is selected and prepared carefully to make sure it has enough blood flow. The beginning of the procedure is the same regardless of what kind of urinary diversion surgery you’re having. That means taking the bladder and some nearby lymph nodes out, and getting the left ureter (the tube that takes urine from the kidney to the bladder) ready to be reconnected elsewhere.
In an Ileal Conduit procedure, a section of the small intestine, called the ileum, is selected. This section is typically about 15 cm long, which leaves enough room to connect the ureters without any pulling or stretching. Then the blood flow to this section of the intestine can be checked by shining a light through it. Next, the section of small intestine is separated on both ends, getting it ready to be used for sending urine out of the body.
After all that is done, the remaining ends of the small intestine are brought back together. This process is completed by cutting off the corners of the intestines and then using a stapling device to put the two ends back together. To finish this off, the opening created by the stapling device is closed with more staples. Then a catheter can be inserted to ensure that urine drains properly, and, finally, the stoma (the opening where urine will pass) is created and connected.
Stents, which are tiny tubes, can be used to help make sure there are no leaks or blockages, but they’re not always necessary. You’ll definitely need to drain the urine out nightly with a special bag to prevent infection. Taking care of your stoma is a critical step after your operation.
In an Orthotopic Neobladder procedure, the bladder is recreated using a part of the ileum, much larger than that in the Ileal Conduit procedure. Here, a “U” shape is created using two lengths of small intestine. This also involves a lot of careful sewing to make sure that the urine stays inside the new bladder and isn’t able to leak out. The ureters are reconnected in much the same way as in the Ileal Conduit procedure. In some cases, stents can be used to help make sure there are no leaks.
The final type of procedure, Continent Cutaneous Urinary Diversion, uses a pouch made from a part of the ascending colon (which is part of the larger intestine) and a portion of the distal ileum to create what we call a “catheterizable channel.” This channel can be used to drain urine from your body with a catheter. The reconstructed intestine is sutured to the colon and intestine, and the ends of this channel are readjusted to create the best possible connections.
All these processes are aimed at using a part of your bowel to replace the functionality of your bladder after its removal. This way, you are able to urinate although the process might be different from previously. It’s best to discuss with your doctor which process is suitable for your particular case.
Possible Complications of Urinary Diversions and Neobladders
Radical cystectomy, a major abdomen operation frequently performed on older patients suffering from cancer, is a complex procedure. This operation often includes urinary diversion and is usually performed on patients with other health conditions like diabetes, and heart and kidney problems. In the first three months after this operation, up to two-thirds of patients may experience a complication, with as many as 20% being high grade or severe. More than half of these surgical complications are due to the urinary diversion part of the procedure, rather than the cystectomy itself. The most commonly reported complications include issues related to the digestive system, infections, and urinary problems.
About 20% of patients might experience prolonged ileus, a disruption in the normal movement of the digestive system after the surgery. Some patients are at a higher risk for developing blood clots due to factors like the type of surgery, presence of cancer, frequent use of chemotherapy before surgery, and older age. This risk can be reduced by giving a special type of blood-thinning medication known as low molecular weight heparin before the surgery and for a month after the surgery.
There have been cases where ureteroenteric stricture, a narrowing of the tube that carries urine from the kidneys to the bladder, has occurred with rates varying between 3% and 17%. Risk factors include conditions like fluid overload in the kidney, urine leak after surgery, urinary tract infections during the operation, previous abdominal surgery, and a history of radiation therapy in the pelvic region. Urine leaks can lead to a condition known as chemical peritonitis and contribute to prolonged ileus.
In the long term, some patients may develop stones in their new bladder at rates between 4% to 6%, and up to 42% in patients with a certain type of urinary diversion. If the intestine that is being used to carry out the urinary diversion is the terminal ileum, it can put patients at risk of Vitamin B12 deficiency. This can result in symptoms like fatigue, weakness, heart palpitations, shortness of breath, dizziness, pale skin, vision problems, mouth ulcers, and mood changes. Regular testing for vitamin B12 levels and supplementing as needed can help prevent these symptoms.
Another long-term issue is hernias forming around the ileal conduit, a part of the intestine used to create a passage for urine, which have been reported in 5% to 65% of cases. Rates of metabolic acidosis, a condition where the body produces too much acid or the kidneys cannot remove enough, can vary. If left untreated, it can lead to bone loss and increased risk of fractures. Regular checks of electrolytes, managing acidosis and supplementation with calcium and vitamin D can prevent this.
Regular use of a special type of scan, called a dual-energy x-ray absorptiometry (DEXA) scan, is recommended to quickly identify and treat any bone loss and osteoporosis.
What Else Should I Know About Urinary Diversions and Neobladders?
The bladder plays a crucial role in storing and releasing urine. When required, procedures like removal of the bladder (cystectomy) and urinary diversion — rerouting urine flow through a different path — can effectively treat bladder cancer. These treatments can help a person live a healthy life even after bladder cancer. However, it should be understood that completely removing the bladder is a significant life event, even if it successfully cures the problem.
After bladder removal, there are various ways urine can be diverted; each method has its unique implications during and after the operation. Surveys have suggested that patients feel better if they actively participate in deciding which method to use after being informed about the pros and cons.
Nowadays, patients who have undergone bladder removal tend to live longer with their urinary diversions. Therefore, it is vital to manage the long-term effects of such a procedure, especially as these patients grow older. Doctors treating these patients should understand the consequences of each urinary diversion method so they can monitor their patients and optimize their treatments.