Editing Orthotopic Urinary Diversion (section)

== Techniques for orthotopic bladder substitution ==

* '''Choice of bowel segment'''
** '''Excellent functional and clinical outcomes with voiding can be achieved regardless of the segment of bowel chosen''' as long as the principles of preservation of the rhabdosphincter as a continence mechanism and construction of an adequate capacity, low-pressure reservoir are maintained
** '''Reservoirs made of detubularized ileum or ileum and colon together appear to have the greatest compliance and lowest likelihood of generating intermittent high-pressure contractions.'''
*** The urodynamic characteristics of the ileum appear to be superior to those of the colon
*** '''Advantages of neobladders made of ileum (6):'''
***# '''Larger capacity'''
***# '''Lower filling pressures'''
***# '''Lower maximum capacity pressures'''
***# '''Better compliance'''
***# '''More mobile mesentery'''
***#* Generally reaches to the urethra without much difficulty
***#* In patients with short ureteral length because of malignancy or other pathology of the ureters, an ileal pouch with a “tail” (such as the Studer) can be extended to reach all the way to the renal pelvis
***# '''Decreased mucous production and decreased reabsorption of urinary electrolytes in the mature reservoir due atrophy of the intestinal mucosa''' as it is exposed to urine over time.
***#* Mucosal atrophy appears to be more reliable in small bowel than in large bowel reservoirs
*** '''The primary disadvantage of using distal ileum lies in the potential loss of absorption of vitamin B12.'''
*** '''Contraindications to use ileum for diversion(3):'''
***# '''Short bowel syndrome'''
***# '''Inflammatory small bowel disease'''
***# '''History of extensive pelvic irradiation''' where the ileum may have been affected
*** Whenever ileum is available, it is preferentially use it for orthotopic diversion.
*** '''Stomach and sigmoid colon have been found to have particularly poor compliance and high pressures'''
**** See Intestinal Segments Chapter Notes
* '''Need to prevent reflux'''
** '''The addition of an antireflux mechanism does not appear to be necessary for preservation of the upper tracts and prevention of infections''', at least in the intermediate term
*** Studies that have compared refluxing versus non-refluxing urinary diversion have been limited, in general, by short follow-up, patient selection bias, retrospective design, or relatively small patient numbers
*** '''Any mechanism introduced to prevent reflux may potentially cause upper tract obstruction.''' Afferent valve obstruction is often clinically silent
* General perioperative management
** Perioperative management of patients undergoing cystectomy and orthotopic diversion is similar to those undergoing other types of diversion
** A pelvic drain should be placed in every patient. The authors leave the drain until the pouch has healed because of occasional late leakage if the catheter gets plugged at home.
** There is no consensus on the ideal management of ureteral stents or catheters in patients undergoing orthotopic diversion. Most authors recommend the use of ureteral stents in the early postoperative period
** When patients return at the 3-week postoperative mark, if there is minimal drainage from the drain (<100 mL during 24 hours), the catheter is removed, followed by the drain. Routine pouchograms or radiographic studies of the neobladder are not routinely performed unless a significant output from the drain is observed.
** Patients receive education throughout the perioperative period regarding catheter management, pelvic floor exercises, and proper voiding technique.
* '''Surgical techniques'''
** '''Ileal reservoirs'''
*** '''Most ileal reservoirs use 60-75 cm of terminal ileum, which is detubularized and folded in a variety of ways to attempt to create a spheric shape. Modifications primarily include variations in the exact folding technique and variations in management of the ureters, with or without an antireflux mechanism'''
*** '''In general, all reservoirs are closed with continuous absorbable suture. The use of nonabsorbable suture and metal staples should be avoided because of the potential for stone formation'''
*** '''The 2 most popular configurations are the Hautmann W-neobladder''' (and its various modifications) '''and the Studer pouch neobladder.''' '''The T pouch and extraserosal tunnel techniques both provide an antireflux mechanism when that is felt to be advantageous'''.
*** '''Ileal neobladder (Hautmann Pouch)'''
**** '''See BJUI Surgical Atlas for details and figures'''
**** Intentionally large-capacity, spheric (W configuration) ileal reservoir that is constructed in an attempt to optimize initial volume and potentially reduce nighttime incontinence.
**** '''A segment of terminal ileum of ≈70 cm is selected'''. The bowel is reconstituted, and the mesenteric trap is closed. The ileal section that reaches the urethra most easily is identified and marked with a traction suture along the antimesenteric border. The isolated bowel segment is then arranged in either an M or W shape and is opened along the antimesenteric border except for a 5-cm section along the traction suture where the incision is curved to make a U-shaped flap.
**** The 4 limbs of the M or W are then sutured to one another with a running absorbable suture. A small full-thickness segment of bowel is excised in the site for the urethral anastomosis, which is then performed with the sutures tied from inside the neobladder. Once the ileal neobladder is situated in the pelvis and the urethral sutures are tied, the ureters are implanted from inside the neobladder through a small incision in the ileum at a convenient site. The remaining portion of the anterior wall is then closed with a running absorbable suture
**** '''This pouch has a larger initial capacity than the Studer pouch, which may assist in earlier continence. However, it may also result in an increased incidence of late urinary retention and increased electrolyte reabsorption from the pouch.'''
*** '''Studer pouch'''
**** '''See BJUI Surgical Atlas for details and figures'''
**** '''Uses a long, afferent, isoperistaltic, tubular ileal segment that is believed to prevent vesicoureteral reflux when the patient voids by Valsalva maneuver'''
**** The advantages of this bladder substitute include the simplicity of construction, the lack of a requirement for surgical staples, and the ability to accommodate short ureters.
**** The reservoir portion uses the optimal double-folded U configuration
**** '''The terminal portion of the ileum (54-56 cm long) is isolated''' approximately 15-20 cm proximal to the ileocecal valve. The distal mesenteric division is made along the avascular plane between the ileocolic artery and terminal branches of the superior mesenteric artery. The proximal mesenteric division, however, is short and provides a broad vascular blood supply to the reservoir. In addition, a small window of mesentery and 5 cm of small bowel proximal to the overall ileal segment are discarded, ensuring mobility to the pouch and small bowel anastomosis. Bowel anastomosis is performed using staplers.
**** The Studer pouch is created from 40-44 cm of distal ileum with each limb of the U measuring 20 to 22 cm and a proximal 15-cm segment of ileum used as the afferent limb. If ureteral length is short or compromised, a longer afferent ileal segment (proximal ileum) may be used. The proximal end of the isolated afferent ileal segment is closed with absorbable suture. The isolated ileal segment is opened about 2 cm away from the mesentery, and the incised ileal mucosa is then oversewn with two layers of a running 3-0 polyglycolic acid suture

*** '''Camey II'''
*** '''Serous-lined extramural tunnel'''
*** '''Orthotopic Kock Ileal Reservoir (Hemi-Kock)'''
**** '''The Kock ileal reservoir was first used as a continent cutaneous ileal reservoir incorporating intussuscepted nipple valves for both the afferent (antireflux) and efferent (continence) limbs. This subsequently evolved into an orthotopic form of diversion in which the afferent intussuscepted limb was maintained to prevent urinary reflux'''
**** The technical difficulty of the intussuscepted nipple valve and the associated complications, along with the development of effective alternative techniques, has made this neobladder procedure primarily of historical interest.
*** '''T pouch modification'''
**** In an effort to preserve an antireflux mechanism but avoid the potential long-term complications seen with the Kock nipple valve, as well as to allow for more flexibility in managing the ureters, the T pouch was developed as a modification of serous-lined ureteral tunnel
** '''Colon and ileocolic pouches'''
*** '''Orthotopic neobladders constructed completely of colon are a good option for patients with multiple previous small bowel resections or who have diseased ileum (e.g. Crohn’s, previous pelvic radiation)'''
*** '''Colon segments are less distensible than ileal segments and may be more likely to produce higher pressure waves causing incontinence. As a consequence,''' '''initial volume should be larger than for an ileal pouch.''' Combined colon and ileal segments can mitigate this problem.
*** '''Orthotopic Mainz Pouch (Mainz III)'''
*** '''Le Bag Pouch'''
*** '''Right Colon Pouch'''
*** '''Sigmoid Pouch'''
**** Patients who are candidates for radical cystectomy often have a redundant sigmoid colon, which is readily available for use.
**** The only concern is the potential compromise of the vasculature of the distal colon segment because of interruption of branches of the internal iliac artery during the cystectomy. It is important, therefore, to maintain as much of the vascular supply to both ends of the bowel anastomosis as possible. Some patients will complain of frequent stools or rectal urgency for a period of time after sigmoid colectomy.
** '''Use of Minimally Invasive Techniques for Orthotopic Diversion'''
*** Postoperative recovery in most series has only been modestly improved compared with open series, with longer operative times but decreased blood loss.
*** Postoperative complications demonstrate mixed results.
*** In the RAZOR trial, which showed non-inferiority of robotic RC vs. open for 2-year PFS and similar rate of complications, 20-24% underwent neobladder diversion