Urinary Diversions and Neobladders

Anatomy and Physiology

The urinary bladder is a muscular, extraperitoneal organ in the pelvis that receives urine from the ureters and drains it via the urethra. This organ is anchored at the apex of its dome to the umbilicus via the median umbilical ligament—a remnant of the fetal urachus. Immediately to the right and left of the median umbilical ligament are the medial umbilical ligaments, which are the remnants of the obliterated umbilical arteries and connect the bladder to the umbilicus. The bladder neck connects to the prostate in men. This organ is attached to the pelvic diaphragm via the medial and lateral puboprostatic ligaments in men and the pubovesical ligaments in women.

The arterial blood supply to the bladder arises from the internal iliac arteries. The superior and inferior vesical arteries, with additional inputs from the obturator and inferior gluteal arteries, as well as from the vaginal and uterine arteries in women, merge to form the lateral and posterior bladder pedicles. Venous drainage from the bladder arises from the vesical venous plexus and drains via the internal iliac veins. Lymphatic drainage from the bladder proceeds via the external iliac, internal iliac, obturator, and common iliac lymph node chains.[3] Further spread to the presacral lymph nodes and the retroperitoneal nodes in the paracaval, interaortocaval, and paraaortic lymph node chains can also be seen.[4][5]

The urinary bladder has 4 distinct layers. The urothelium is the innermost layer and comprises the transitional epithelium (urothelium), which is 7 to 10 cells deep and is composed of apical, intermediate, and basal cells. The apical umbrella cells are in direct contact with the urine. They are the first defensive barrier for uropathogenic bacteria while allowing for selective transport of electrolytes across the bladder membrane.[6] Tight junctions and uroplakin proteins render the urothelium impermeable, and these uroplakins are primary attachment sites for uropathogenic Escherichia coli infections.[7] 

The lamina propria layer, located deep in the urothelium, contains connective tissue, lymphatics, nerves, and blood vessels. Deep to the lamina propria is the muscularis propria, which consists of smooth muscle known as the detrusor, which is responsible for bladder contractions. The muscle fascicles within the body of the bladder above the trigone are arranged in random directions, while they adopt a layered circular configuration in the trigone and bladder neck. These structural characteristics enable the bladder to expand effectively to accommodate urine and empty it in a coordinated manner. The compliance afforded by the bladder's multilayered design allows for low-pressure filling. Beyond the muscularis are the final layers of the bladder, serosa, and fat. These anatomical features are important in understanding and treating bladder cancer. Once bladder cancer invades the lamina propria layer, the potential for metastasis via lymphatics and blood vessels increases.[8] For cancers that are muscle-invasive, high-grade (carcinoma in situ), and recurrent, or Bacille Calmette-Guérin (BCG)-unresponsive, or unresectable using endoscopic techniques, bladder removal through radical cystectomy is the recommended standard of care.

Performing a complete lymph node dissection, according to the lymphatic drainage pattern described above, is integral to surgical treatment.[9][10] The lymphatic spread of bladder cancer can be seen in ipsilateral or contralateral pelvic lymph nodes, necessitating a bilateral pelvic lymph node dissection regardless of the location of cancer within the bladder.[11]

When considering urinary tract reconstruction after bladder removal, both the continent and incontinent diversion surgical techniques are available. The choice of reconstruction must include the patient's desires, abilities, and motivation, as well as medical comorbidities and prior surgical or radiation history. These factors will determine both the type of reconstruction performed and the choice of bowel segment to be used in the reconstruction.

Different bowel segments have been used in various configurations to create urinary diversions. While the ileum and colon are the most commonly used segments, the stomach and jejunum have also been employed, albeit less frequently. However, the use of bowel segments in urinary diversion can lead to metabolic consequences. Factors contributing to metabolic derangements include the choice of bowel segment, the surface area of the bowel segment utilized, and the duration of urine contact time in the bowel.[12]

When creating a neobladder or continent cutaneous pouch, the choice of bowel segment and configuration must enable the reservoir to store urine at low pressure, preventing damage to the upper urinary tract. Additionally, the reservoir should have the capacity to expand, facilitating volitional emptying at intervals short enough to avoid excessive metabolic consequences while also retaining urine for several hours to achieve social continence.[13] 

Metabolic consequences are less pronounced in the ileal conduit due to the utilization of a shorter segment of the bowel and decreased urine dwell time. Appropriate bowel selection is essential to ensure the stoma is positioned effectively for the self-care of appliances.[2] The distal ileum is the most commonly used bowel segment for urinary conduits and orthotopic neobladders. The ileum has a relatively small diameter and is highly mobile, facilitating optimal positioning in the abdomen or pelvis, supported by a reliable blood supply from the superior mesenteric artery. The ileum can be opened and folded to create a low-pressure reservoir as required for a neobladder.

In rare cases, the ileal mesentery may be short or thickened, making it difficult to fold and position adequately in the pelvis for an orthotopic neobladder. An ileal conduit or continent cutaneous diversion may be necessary in such cases. Although the ileum is rarely involved in radiation fields, prior pelvic irradiation has historically indicated the use of a transverse colon conduit. However, recent studies indicate that the ileum can safely be utilized in cases of prior pelvic radiation.[14]

Both the ileum and colon segments can absorb ammonium, hydrogen, and chloride from urine while excreting bicarbonate.[15] This absorption pattern can result in hyperchloremic metabolic acidosis, with an increased risk associated with prolonged urine/bowel contact time. The jejunum is rarely used due to its highly porous epithelium, which permits larger volumes of water to move osmotically into the bowel lumen, potentially resulting in chronic dehydration. Additionally, the jejunum possesses chloride-bicarbonate antiports but lacks the sodium-potassium antiports present in the ileum and colon. This can result in a state of hypochloremic, hyponatremic, hyperkalemic metabolic acidosis, which has been associated with symptoms such as nausea, weakness, seizures, and dehydration.[16]

Indications

Radical cystectomy with urinary diversion is the most effective treatment for muscle-invasive bladder cancers, with 5-year cancer-specific survival rates reported up to 76% using this treatment.[17] Most patients are eligible for all urinary reconstructive options. All patients being considered for radical cystectomy should receive counseling about the different types of urinary diversion options and the associated risks and benefits of each.[18] 

Patient-unique and disease-specific factors are important considerations in choosing the appropriate diversion. Patients desiring an orthotopic neobladder must be motivated to adhere to a timed voiding regimen postoperatively and capable of performing clean intermittent catheterization if necessary. These patients should also be advised about the difference in voiding technique, including the use of Valsalva voiding.

Similarly, patients should understand the potential for daytime or nighttime incontinence after neobladder creation. Patients undergoing an ileal conduit should understand and be capable of caring for their ostomy and appliance. Those considering continent cutaneous urinary diversions must understand that urinary drainage depends on regular, clean, intermittent self-catheterization 4 to 6 times daily.

Contraindications

While older age is not a contraindication for neobladder reconstruction, older individuals should be counseled about the higher risk of delayed recovery of urinary control and the increased long-term risk of nocturnal incontinence.[19] An ileal conduit is technically less complicated to perform and can lead to shorter operative times with less bowel manipulation compared to neobladder or continent cutaneous diversions. This technique is associated with decreased short-term surgery-related complications and may be more appropriate for older or more frail patients.[12][20]

Patients with cognitive impairment, degenerative neurologic disease, or frailty should be counseled that continent diversions may require dexterity and attention beyond what may be available or possible from family members, caretakers, visiting nurses, or long-term care facilities, and an ileal conduit may better serve them.[21] 

Approximately 10% of men and up to half of women require intermittent catheterization to empty their neobladders adequately. Therefore, poor manual dexterity and an unwillingness to perform or commit to self-catheterization are contraindications to neobladder creation.[20][22] Similarly, severe urethral stricture disease is also a contraindication to orthotopic neobladder due to the same reason. Significant preoperative urinary incontinence may indicate poor urinary continence with an orthotopic neobladder, and these patients may benefit more from an ileal conduit or continent cutaneous diversion.[23]

An orthotopic neobladder is contraindicated in patients with malignancy involving the urethra, either grossly or on intraoperative frozen sectioning, as they are at increased risk for urethral recurrence of the disease. Significant diseases outside the bladder and plans for adjuvant radiation are also contraindications to neobladder creation.[24] 

Historically, prior pelvic radiation therapy has been considered an additional contraindication for neobladder creation and usage. Studies have demonstrated that while technically feasible, neobladder formation after prior radiation exposure is associated with increased complications and incontinence rates. Therefore, patients with a history of pelvic radiation therapy may benefit more from an ileal conduit or continent cutaneous urinary diversion.[25]

Similarly, patients with chronic renal or hepatic insufficiency should not undergo orthotopic neobladder surgery. Chronic metabolic acidosis can lead to progressive kidney disease. Many centers use an estimated creatinine clearance of 35 to 40 mL/min as a minimal requirement for continent diversions.[24] Adequate hepatic function is necessary to manage the reabsorption of ammonium across the bowel mucosa in neobladders. Therefore, hepatic insufficiency is also a contraindication for a neobladder.[2]

Preparation

Detailed past medical and surgical histories of patients are crucial to adequately prepare both the patient and the medical team for urinary diversion surgery. Prior abdominal surgeries and radiation history, including specific attention to radiation fields that may involve the bowel or bladder, are crucial for surgical decision-making. A history of inflammatory bowel disease may restrict the use of the colon in diversions. Therefore, a colonoscopy should be conducted before using the colon in continent cutaneous urinary diversions to exclude malignancy or evidence of chronic inflammatory bowel disease.[18]

Thorough counseling regarding cystectomy and diversion types is associated with less regret concerning the type of diversion performed and better quality of life scores postoperatively.[26][27] Multidisciplinary teams, including surgeons, primary care physicians, and enterostomal therapists, can assist with patient counseling. Given that many bladder cancer patients undergoing cystectomy have a significant history of tobacco use, smoking cessation counseling is also advised and has been demonstrated to improve perioperative outcomes.[28] 

Considering that preoperative nutritional status, as measured by albumin levels, has been demonstrated to correlate with perioperative outcomes following cystectomy with urinary diversion, preoperative nutritional consultations should be considered.[29][30] In addition, given that the median age for bladder cancer diagnosis falls between 69 and 73, many older cystectomy patients will require consultations and optimization by their primary care providers, cardiologists, or geriatricians.[31][32]

Patients undergoing small bowel diversions such as ileal conduit or orthotopic neobladder typically do not undergo bowel preparation as a routine practice. However, many institutions still recommend standard mechanical bowel preparation when the colon is utilized for a conduit or continent cutaneous urinary diversion.[33] 

Preoperative and perioperative administration of peripherally acting opioid receptor antagonists has been linked to an earlier return of bowel function and shorter hospital stays.[34] Accordingly, the American Urological Association recommends antibiotic prophylaxis with second- or third-generation cephalosporins perioperatively.

Technique or Treatment

General techniques for ileal conduit, orthotopic neobladder, and continent cutaneous urinary diversions are described below. Open and minimally invasive approaches are utilized, including laparoscopy and robotic assistance. Ensuring adequate exposure and bowel mobilization for tension-free anastomoses is critical across all diversion types and surgical approaches. Care should be taken to carefully evaluate the blood supply to each segment of the bowel used in the urinary reconstruction to ensure the diversion is well-perfused. The diversion starts after removing the bladder and lymph nodes in each case. The left ureter is passed behind the sigmoid mesentery in preparation for the ureteral anastomosis for each reconstruction.

Ileal Conduit

An appropriate portion of the ileum, approximately 15 cm proximal to the ileocecal valve, is selected. The length of the conduit is chosen to allow for appropriate positioning and tension-free anastomoses of the ureters to the proximal end of the conduit, with about 15 cm of ileum generally required for the diversion. The mesenteric blood supply can be visualized by lifting the distal ileum and shining a light through to visualize the avascular plane for the division, ensuring adequate blood supply to the conduit.

The distal division is made along the avascular line of Treves, between the ileocecal artery and the terminal branch of the superior mesenteric artery. The mesentery is then divided using a ligature device or with suture ligation. The proximal mesenteric division should be shorter than the distal division, as the distal segment requires greater mobilization to reach the skin. The distal division requires dividing the vascular arcade connecting the terminal branch of the superior mesenteric artery and the ileocolic artery. A gastrointestinal anastomosis (GIA) stapling device is then used to divide the proximal and distal segments of the conduit.

The conduit is then placed into the pelvis, and the portion of the ileum to be reconnected to restore bowel continuity is elevated and brought together. A side-to-side anastomosis is completed by excising the antimesenteric corners of the proximal and distal bowel to be reconnected. A GIA stapling device is then used for the anastomosis. The end of the anastomosis is closed with a transverse anastomosis (TA) stapler after the ends are aligned with Allis clamps. The staple line is reinforced, and the mesenteric defect between the anastomosed bowel segments is realigned with interrupted sutures. Using the Parker-Kerr technique, the staple line at the proximal end of the ileal conduit is excised and closed with running sutures in 2 layers. The conduit is then aligned to allow for ureteral anastomosis.

The ureters are brought to the proximal end of the conduit and further tapered and spatulated to allow for anastomosis without excessive tension or redundancy, which may cause kinking and obstruction. Care must be taken not to handle the ureters directly to avoid damaging the blood supply located in the adventitial layer. The bowel serosa is grasped, and enterotomies are made for the ureteral anastomosis, which can be performed with interrupted or running absorbable sutures. Some centers place temporary ureteral stents to help decrease early urinary leaks and strictures at anastomotic sites. However, stents are not uniformly used, and their role is debated in the literature.[34][35]

The stoma is then brought through the belly of the rectus muscle and matured to the skin at the preselected site. Turnbull loop stomas or rosebud stomas may be created at the surgeon's discretion. After the stoma is matured, the proximal end of the conduit is retroperitonealized by tracking the medial peritoneal flap to the conduit. A stomal catheter is often placed temporarily to ensure adequate drainage of the conduit during the early perioperative period. After recovery, patients should be instructed to change their urostomy appliance every 3 to 4 days and attach a urinary drainage bag to their ostomy appliance at night to ensure the urine drains away from the conduit. Urine refluxing into the conduit can lead to skin breakdown, increasing the risk of urinary infection. The appliance does not need to be sterilized, and the conduit does not require irrigation. Simple hydration effectively promotes adequate urine flow to avoid stasis and infection.

Orthotopic Neobladder

Numerous orthotopic neobladder diversions have been described, each of which relies on creating a low-pressure reservoir based on double folding of the ileal segment. The distal division, approximately 15 cm proximal to the ileocecal valve, is performed identically to the ileal conduit. However, the mesenteric division distally can be deeper to allow for greater mobilization of the bowel segment into the pelvis. Approximately 55 cm of the bowel is measured proximal to this distal division to create the neobladder. The bowel to be used for the neobladder is placed into the pelvis while the bowel to be reconnected is anastomosed, and the mesenteric trap is closed in an identical manner as described previously.

Segments of the ileum (2 in total and measuring 20 cm) are utilized for the neobladder, with an additional 15 cm of more proximal ileum allocated for the afferent limb to facilitate ureteral anastomoses. The back wall of the 2 20-cm segments is aligned to create a "U" configuration. The bowel is detubularized on the antimesenteric border, except for the proximal afferent limb. The posterior plate is closed with a running 2-layer closure, and the pouch is folded in half in the opposite direction of the posterior plate. The anterior wall is closed, with the distal suture line remaining open for ultimate anastomosis to the urethra.

The ureters are anastomosed to the afferent limb using the same technique as described earlier for the ileal conduit. The reservoir is positioned in the pelvis, and the urethra-enteric anastomosis is accomplished with interrupted sutures around a Foley catheter. If used, ureteral stents can be secured to the catheter or externalized. Suprapubic catheter drainage of the neobladder may be used in addition to Foley catheter drainage at the surgeon's discretion.

Continent Cutaneous Urinary Diversion

Although multiple configurations of continent cutaneous urinary diversions have been described, the most performed technique uses a pouch created using the ascending colon and a catheterizable channel created by a portion of the distal ileum. Approximately 30 cm of ascending colon is selected, de-fatted, and divided using a GIA stapler. For the catheterizable channel, a 10-cm segment of the terminal ileum is selected. The bowel is divided, and continuity is reestablished by anastomosing the terminal ileum to the transverse colon in a side-to-side manner, as outlined previously.

The isolated colon segment undergoes detubularization along the anterior tenia, ensuring the preservation of the ileocecal valve. The catheterizable channel, formed from the terminal ileum, is tapered around a 14 Fr catheter using running sutures, with reinforcement of the ileocecal valve to serve as the continence mechanism. Sites for ureteroenteric anastomoses are selected on the posterior wall of the detubularized colon. A minor colonic hiatus is established for each ureteral anastomosis, and each ureter is guided from outside to inside the colonic pouch.

The ureteral segments are shortened and adjusted as necessary to remove any redundant or poorly perfused areas. They are then spatulated and anastomosed from within the pouch using either interrupted or running absorbable sutures, and stents can be placed at the surgeon's discretion. Following the completion of the ureterocolonic anastomoses, the open colon segment is folded and approximated in two layers using absorbable sutures. If needed, a cecostomy tube can be inserted through the anterior wall of the pouch. Subsequently, the catheterizable channel is brought to the predetermined stoma site and secured to the skin using interrupted absorbable sutures following a V-shaped incision. Finally, a stoma catheter is inserted and fastened in place.

Complications

Radical cystectomy with urinary diversion is a complex major abdominal operation frequently performed on older patients with cancer, often accompanied by diabetes, renal, and cardiopulmonary comorbidities.[36] During the first 90 days after surgery, as many as two-thirds of patients may experience a complication, with up to 20% being high grade.[37][38] Over half of surgical complications can be attributed to the urinary diversion rather than the cystectomy.[37] The most commonly reported complications of cystectomy with urinary diversion in several series include gastrointestinal, infectious, and urinary issues.[38][39][40] 

Prolonged ileus can be seen in approximately 20% of cases.[41] Risk factors for perioperative venous thromboembolic events include major pelvic surgery, the presence of malignancy, the frequent use of neoadjuvant chemotherapy, and older age.[42] This risk can be mitigated by administering prophylactic low molecular weight heparin preoperatively and 28 days postoperatively.

Ureteroenteric stricture rates between 3% and 17% have been reported, with increasing rates described with longer follow-up.[40][43] Risk factors for stricture include preoperative hydronephrosis, postoperative urine leak, perioperative urinary tract infection, prior abdominal surgery, and a history of pelvic radiation. Urine leaks from the ureteral anastomosis in the perioperative period can induce chemical peritonitis and contribute to prolonged ileus. The resulting urinomas may become infected and require drainage.

In the longer term, stones have been found to form in 4% to 6% of patients with neobladders and up to 42% of those with continent cutaneous diversions.[44][45] Parastomal hernias surrounding the ileal conduit have been reported in 5% to 65% of cases, with approximately one-third eventually requiring surgical repair.[24] Chronic acidosis and stasis contribute to the formation of urinary stones in these patients.

Rates of metabolic acidosis vary from 5% to 15% for ileal conduits, 6% to 13% for orthotopic neobladders, and 26% to 45% for continent cutaneous diversions in recent series.[19][46][47] Chronic acidosis can lead to bone demineralization and osteopenia, with patients who have baseline renal insufficiency being at even higher risk.[47][44] SEER analysis showed cystectomy patients have a 21% greater risk of fracture than those without a cystectomy history.[12] Regular evaluation of electrolytes, correction of acidosis, and supplementation with calcium and vitamin D, along with either bisphosphonates or RANK ligand inhibitors, will likely help prevent this acidosis-induced bone demineralization. Periodic dual-energy x-ray absorptiometry (DEXA) scans are recommended to identify and treat any osteopenia and osteoporosis promptly.

The terminal ileum is the site of vitamin B12 absorption, and patients with diversions that use this intestinal segment are at risk of B12 deficiency. Symptoms of vitamin B12 depletion are nonspecific and include lethargy, extreme fatigue, weakness, palpitations, shortness of breath, dizziness, extremely pale skin, neuropathy, visual disturbances, mouth ulcers, and mood changes. The depletion of B12 can take 3 to 4 years to manifest.[16] Annual vitamin B12 surveillance and supplementation as needed can prevent sequelae of B12 deficiency.

Clinical Significance

The bladder is critical in storing and releasing urine. When indicated, cystectomy and urinary diversion can effectively treat bladder cancer while maintaining a good quality of life. However, bladder removal is a life-changing event, even when it cures the underlying problem as intended. Various urinary diversion options are available after cystectomy, each with unique considerations in the perioperative and postoperative periods. Patient-reported quality of life surveys show improvement if patients describe their post-diversion-related goals and participate in informed shared decision-making with their medical team preoperatively.[26] 

Cystectomy patients now live longer with their urinary diversions, making the long-term treatment of associated age-related conditions essential. Physicians treating these patients should be aware of the short- and long-term consequences of the various urinary diversion types and be prepared to optimize their surveillance and treatment.

Enhancing Healthcare Team Outcomes

Cystectomy with urinary diversion is a complex surgery commonly performed in an older and more comorbid patient population. Outcomes have been shown to be improved in centers that perform more operations and have healthcare teams accustomed to the specialized care needed in these patients.[48][49] The interprofessional healthcare team includes urologists, advanced care practitioners, nurses, pharmacists, physical and occupational therapists, and other healthcare professionals. Effective communication and collaboration among team members are crucial for coordinating comprehensive, patient-centered care and enhancing patient safety.

Optimization of surgical outcomes following cystectomy and urinary diversions begins before surgery with preoperative counseling and treatment of underlying disorders. Perioperative management with standardized enhanced recovery after surgery (ERAS) clinical pathways can improve outcomes with hospital stays decreased from 1 week or more to 3 to 4 days.[50] 

Common pathway components include narcotic-sparing pain management, which often begins preoperatively with epidural anesthesia or regional blocks. Additionally, early enteral feeding, bowel optimization with opioid antagonists, aggressive ambulation, and early involvement of physical therapy, as well as enterostomal therapists, can improve perioperative outcomes. Early postoperative mobilization with the assistance of physical therapists can also help shorten hospital stays. Occupational therapy for older patients may be necessary in optimizing each patient’s ability to care for their urinary diversion at home.

Improved clinical outcomes result from meticulous surgical technique, thorough patient education, and effective postoperative care, reducing complications and enhancing quality of life. High-performing teams demonstrate collaborative problem-solving, mutual respect, and shared goals. Regular training and debriefing sessions can improve team dynamics and performance, ultimately benefiting patient care.

Nursing, Allied Health, and Interprofessional Team Interventions

Multiple healthcare teams collaborate to provide comprehensive care to patients needing cystectomy with urinary diversion. As part of multidisciplinary care, preoperative and perioperative evaluation and management by nutritionists, anesthesia and pain management teams, geriatricians, smoking cessation counselors, and primary care teams are essential. Physical and occupational therapists also play crucial roles.

Preoperative evaluation of all patients undergoing cystectomy by a dedicated enterostomal therapist is critical, even if an orthotopic neobladder is desired as the primary reconstructive option. Intraoperative assessments may occasionally necessitate conversion to ileal conduit or continent cutaneous urinary diversion. Preoperative abdominal evaluations in varying positions can allow for ideal placement of ileal conduit stoma or catheterizable channel. Preoperative marking of the stoma site ensures accurate placement of the ostomy by a surgeon, facilitating comprehensive preoperative counseling with the patient and family.

The stoma is most commonly situated in the right lower quadrant of the abdomen. Careful consideration should be given to its placement, ensuring it is distant from the midline incision for optimal wound healing and within the patient's line of sight. Preoperative marking has been associated with improved independent ostomy care, decreased stoma-related complications, easier and more secure appliance application, and earlier resumption of normal activities.[51][52][53] Regular postoperative care by surgical, enterostomal, and primary care teams remains essential for the ongoing treatment of patients with cystectomy.