Editing Orthotopic Urinary Diversion (section)

== Patient selection for orthotopic diversion ==

* '''It is estimated that ≈80-90% of male patients and 75% of female patients undergoing cystectomy are potential candidates for neobladder construction from a purely medical standpoint'''
* '''UrologySchool.com Summary of Contraindications (6):'''
*# '''Insufficient bowel length'''
*# '''Unwillingness or inability to self-catheterize'''
*# '''Renal insufficiency'''
*#* '''eGFR <45 ml/min (based on 2019 AUA MIBC guidelines)'''
*#* '''A patient with serum creatinine > 2 mg/dL (177 µmol/L) may be considered for a continent diversion if:'''
*#*# '''GFR > 35 mL/min'''
*#*# '''Able to achieve a urine ≤ pH of 5.8 after an ammonium chloride load'''
*#*# '''Able to achieve urine osmolality ≥ 600 mOsm/kg in response to water deprivation'''
*#*# '''Minimal protein in the urine'''
*# '''Hepatic dysfunction'''
*# '''Indications for urethrectomy'''
*## '''Positive urethral margin'''
*##* CIS in bladder, multifocal tumour, bladder neck tumour, locally advanced disease are not contraindications
*## '''Males with:'''
*### '''High grade or invasive urethral disease distal to the prostatic urethra'''
*### '''Suspected prostatic stromal involvement'''
*## '''Females with bladder neck tumours'''
*# '''Severe urethral stricture disease'''
*** '''Note that first 4 also apply to non-orthotopic continent urinary diversions'''

* '''Oncologic considerations'''
** '''Locally advanced tumour stage'''
*** Many avoid continent orthotopic diversion in patients with locally extensive disease based on 2 factors:
**** Concern about the possible impact of local recurrence on the neobladder itself
**** Belief that these patients are doomed to suffer distant recurrence and have a shortened life expectancy and will not benefit from the neobladder
*** '''Local recurrence even for patients demonstrating locally advanced or lymph node positive disease is relatively infrequent and a significant proportion of these patients will be long-term survivors and may benefit from continent diversion'''
**** '''Risk of recurrence is not increased by careful preservation of the urethra during the cystectomy'''
*** '''If local tumor recurrence does develop in patients with an orthotopic diversion, only a minority will develop problems related to the urinary diversion itself'''
*** '''The presence of extravesical disease should not preclude orthotopic diversion.'''
* '''Patient-related considerations'''

** A number of patient-related factors need to be considered when advising a patient about the best form of urinary diversion, including the patient’s general health and social circumstances, baseline renal function, presence of a healthy urethra and functioning sphincter muscle, manual dexterity, and previous treatments including pelvic radiation, prostate surgery, or bowel resection. Equally important is the patient’s personal preference and attitudes about the risk of incontinence, potential need to self-catheterize, and management of an external appliance.
** '''Patients with poor general health, high surgical risks, the frail elderly, difficult social circumstances, or poor cognitive function are probably best managed with an ileal conduit'''
** '''Chronologic age and obesity are not contraindications for orthotopic diversion'''
** '''Renal function'''
*** Urinary electrolytes including urea, potassium, and chloride are reabsorbed from the small bowel mucosa with excretion of sodium and bicarbonate, resulting in an increased acid load that must be processed by the kidneys. In patients with compromised renal function, hyperchloremic metabolic acidosis can develop along with worsening dehydration, uremia, nausea, and bone loss.
*** Compromised renal function (eGFR <35-50 ml/min [<45 as per 2019 AUA MIBC Guidelines or serum Cr >150-200 μmol/L (1.7 – 2.2 mg/dL) is a contraindication for continent neobladder reconstruction
**** The exact level of acceptable renal function for consideration for continent diversion is unclear
*** '''Orthotopic diversion does not lead to progressive renal dysfunction in patients with normal renal function before surgery'''
** Hepatic dysfunction
*** Similar to the kidneys, the liver must deal with an increased metabolic load with urinary diversion
** Manual dexterity and willingness to do self-catheterization
*** All patients considered for continent diversion should be willing and able to do self-catheterization since it is impossible to predict which patients will require catheterization to empty, and retention can occur many years after the initial surgery
** '''Insufficient bowel length'''
*** '''Orthotopic diversion requires more length (ileal reservoirs require 60-75cm) than ileal conduit (10-15cm)'''
*** '''A patient with multiple prior bowel resections, such as those with Crohn’s, may be at risk of developing chronic diarrhea or even short bowel syndrome after an additional 60 cm of small bowel is resected. In these patients, alternatives to orthotopic diversion such as a sigmoid neobladder should be considered.'''
*** '''In general, prior bowel resections can be managed by carefully dissecting out all of the small bowel, taking down any adhesions before performing the diversion.'''
**** '''In patients with prior bowel resection, it is critical to identify the old bowel anastomosis and, whenever possible, take that down and use that site as one end of the continent reservoir. This avoids potential devascularization of the bowel segment between the old and new bowel anastomoses.'''
** Urethral stricture disease
*** Severe urethral stricture disease in men and women is a contraindication for orthotopic diversion.
** '''Prior pelvic radiation'''
*** '''In carefully selected patients, orthotopic lower urinary tract reconstruction can be performed after definitive, full-dose pelvic irradiation.'''
*** '''Ileum should not used for diversion in patients with previous pelvic radiation'''
*** Previous high-dose prostate radiation (external beam or brachytherapy) or a vaginal implant for cervical cancer cause more '''scarring in the rhabdosphincter area''' than does external beam radiation for either bladder cancer or other malignancies. Interstitial seed implants for prostate cancer often end up in the levator muscles and urogenital diaphragm and may result in severe scarring around the area of the external sphincter.
*** Patients with prior radiation are at increased risk of several complications, even with an ileal conduit diversion.
*** '''Preoperative evaluation including cystoscopy is mandatory to evaluate the integrity of the mucosa around the area of the sphincter'''. However, it may not be possible to accurately predict the degree of radiation damage found at surgery, so careful intraoperative tissue assessment and determination of the condition of the urethra, ureters, and bowel must be performed to make a final decision about the feasibility of orthotopic diversion. '''These patients should always be counseled preoperatively that the orthotopic diversion may not be possible.'''
** '''Prior prostate surgery'''
*** Patients who have had a prior radical prostatectomy may have a particularly difficult dissection around the proximal urethra at the prior vesicourethral anastomosis. Nevertheless, this is often feasible with careful dissection.
*** With careful dissection a patient who was continent after the initial radical prostatectomy surgery can be expected to have an acceptable result with a neobladder.
** '''External sphincter damage'''
*** Poor sphincter function in a patient who is highly motivated to undergo orthotopic diversion may be managed with a concomitant or delayed anti-incontinence procedure