Three14 141 Orthotopic Urinary Diversion

  1. Basic principles of orthotopic neobladder construction?
    • • Patient must have a healthy unobstructed urethra and adequate external sphincter function to maintain continence.
    • •  The reservoir must be sufficiently compliant to maintain a low pressure throughout the filling phase. This is best achieved by opening the bowel segment longitudinally to completely detubularize it and folding it to create a spheric shape.
    • • Ultimate storage volume should be at least 300 to 500 mL at low pressure. The bladder volume achieved through bladder reconstruction must accommodate the patient's urinary output for an acceptable period of time, usually 4 hours

    Colonic segments do not stretch up as easily, and a larger initial volume is necessary for pouches constructed out of colon. In general, small bowel, when available, has  advantages over colon in terms of wall compliance and ability to stretch, as well as reduced mucous formation.

    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. 

    Stomach and sigmoid colon have been found to have particularly poor compliance and high pressures.

    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.

    If colon is used for diversion, colonoscopy should be done before procedure.

    The use of nonabsorbable suture and metal staples should be avoided because of the potential for stone formation.
  2. Patient selection for continent orthotopic diversion?
    • Oncological factors
    • • The presence of CIS, multifocal tumor, or extravesical disease should not preclude orthotopic diversion if frozen section of the urethral margin is negative at surgery. Presence of urothelial carcinoma at urethral margin on frozen section is absolute contraindication to orthotopic diversion. 

    • • The most significant risk factor for a urethral tumor recurrence
    • - in men - presence of prostatic stromal invasion
    • - in women - bladder neck or with palpable extension into the vaginal wall 

    • Intraoperative frozen-section analysis of the urethral margin in men and women provides an accurate assessment of the urethra and appropriately determines candidacy for orthotopic diversion. Preoperative biopsy of the prostatic urethra or bladder neck is not mandatory.


    Patient related factors 

    • • eGFR > 35 or 40 mL/min
    • • Older age and obesity are not contraindications.
    • • In patients with prior bowel resection the prior anastomosis should be taken down and that segment used for the orthotopic diversion rather than choosing a new site, to avoid devascularization of the bowel.
  3. Describe about indications and contraindications of orthotopic neobladder after radical cystectomy. (TU 75-5)

    Contraindications of orthotopic neobladder?
    • Medical
    • Compromised renal function - Serum creatinine >2.0 mg/dL or creatinine clearance <60 mL/min
    • Severe hepatic dysfunction
    • Compromised intestinal function
    • Inflammatory bowel disease
    • Radiation enteritis
    • External sphincter dysfunction
    • Severe urethral stricture disease
    • Severe mental impairment

    • Oncologic
    • Bladder neck involvement: female patient
    • Prostatic urethral or apical involvement: male patient
    • Need for simultaneous urethrectomy
    • Failure to achieve negative urethral margin
    • The distal two thirds of the female urethra may serve as an adequate sphincter mechanism provided that the risk of cancer in the retained urethra is low. Anterior vaginal wall involvement—by a posterior-based bladder tumor or bladder neck or urethral involvement—is a contraindication to urethral sparing and orthotopic bladder replacement because one cannot get an adequate distal vaginal margin and urethral margin.
  4. Continence mechanism in patients undergoing orthotopic diversion?
    The female urethral sphincter system consists of smooth muscle innervated by the autonomic nervous system and striated muscle supplied by somatic nerves. There is general agreement that the autonomic nerves that serve the smooth muscle sphincter originate in the pelvic plexus. These autonomic fibers emerge from the pelvic plexus and course along the lateral aspect of the rectum and vagina toward the bladder neck and very proximal urethra.


    • Male rhabdosphincter as an independent muscle unit that is not in direct contact with the fibers of the levator ani muscle.
    • Male sphincter does not form a horizontal muscular ring around the membranous urethra. Rather, the male rhabdosphincter is a muscular coat situated ventral and lateral to the membranous urethra and prostate, the core of which is an omega-shaped loop that surrounds the membranous urethra.
    • The innervation of the male rhabdosphincter originate from fine branches that arise off the pudendal nerve. Injury to either the rhabdosphincter or the pudendal innervation may impair the sphincter mechanism in men.
  5. Surgical techniques to preserve continence during radical cystectomy?
    • Anterior Apical Dissection in the Male Patient
    • - Minimal manipulation of the muscle fibers of the rhabdosphincter, fascial attachments, and corresponding innervation is essential to providing optimal urinary continence
    • - Posterior dissection should not extend distally to the apex of the prostate. If a nerve-sparing approach is planned, the urethra may be divided after the lateral pedicles are taken down to the bladder (anterior branches of the internal iliac vessels) before the posterior dissection is performed. The prostate is then dissected in a retrograde fashion off the rectum and bilateral neurovascular bundles, and the posterior pedicles are divided last.


    • Preservation of the Urethra in the Female Patient
    • - It appears that preserving the uterus and its supportive ligaments eliminate the risk of vaginal fistula, improves sexual function, and may decrease urinary retention in women undergoing neobladder reconstruction. 
    • - In female patients, the endopelvic fascia and levator muscles should not be disturbed
  6. Describe different types of orthotopic neobladder and patients follow up in the postoperative period. (TU 72-10)

    Types of reservoir pouch?
    • Ileal Pouch - The two most popular configurations around the world are the Hautmann W-neobladder (and its various modifications) and the Studer pouch neobladder
    • - Camey II 
    • - Orthotopic Kock Ileal Reservoir (Hemi-Kock) - originally used for cutaneous continent ileal reservoir 
    • - Serous lined extramural tunnel 
    • - Ileal Neobladder (Hautmann Pouch) 
    • - Studer Pouch 

    • Colic and Ileocolic Pouch 
    • - Orthotopic Mainz Pouch (Mainz III) 
    • - Le Bag Pouch 
    • - Right colon Pouch 
    • - Sigmoid Pouch
  7. Length of Pouches?
    • Koch - 61cm, Ileum 
    • Camey - 65cm, ileum, z shaped 
    • Hautmann - 70cm, w shaped 
    • Studer - 44+15, 
    • Mainz - 15cm cecum, 30 cm ileum 

    >60 cm - risk of retention

    HautMann - M or W shaped  from ileum [@ M]
  8. Construction of the Hautmann ileal neobladder?
    This neobladder is an intentionally large-capacity, spheric (W configuration) ileal  reservoir that is constructed in an attempt to optimize initial volume and potentially reduce nighttime incontinence. 

    Image Upload 1

    • A, A70-cm portion of terminal ileum is selected. The isolated segment of ileum is incised on the antimesenteric border.
    • B, The ileum is arranged into an M or W configuration with the four limbs sutured to one another.
    • C, After a buttonhole of ileum is removed on an  antimesenteric portion of the ileum, the urethral anastomosis is performed. The ureteral anastomoses are performed using a Le Duc technique or direct implantation and are stented, and the reservoir is then closed in a side-to-side manner. As an alternative, the two ends of the W may be left slightly longer as a short chimney on either side for implantation of the ureters. 

    • With Le Duc antireflux ureteral anastomosis, ureteroilial strictures are high.
    • Later, the technique was modified  that uses a freely refluxing, open end-to-side anastomosis implanted into short tubularized segments at each end of the W. This resulted in a decrease in the risk of ureteroileal stenosis from 9.5% to 1%.

    This pouch has larger capacity than Studer Pouch, which may assisted in earlier continence. However, this may result in increased incidence of late urinary retention and increased electrolyte absorption form the pouch.
  9. Enlist the steps of making a Studer pouch. (TU 69,75-3)

    Studer Pouch?
    • The terminal portion of the ileum (54 to 56 cm long) is isolated approximately 15 to 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 to 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. 
    • The reservoir is then closed by folding it in half in the opposite direction to which it was opened.
    • Once the reservoir is folded in half, the anterior wall is closed with a two-layer 3-0 polyglycolic acid suture that is watertight. Note that the anterior suture line is stopped just short of the (patient) right side to allow insertion of an index finger, which will become the neobladder neck. Conversely a new buttonhole can be created at the most dependent portion of  the pouch.
    • Each ureter is spatulated and a standard bilateral end-to-side  ureteroileal anastomosis is performed using interrupted 4-0  polyglycolic acid suture.
    • The reservoir is anastomosed to the urethra using the  previously placed urethral sutures.

    Image Upload 2
  10. Orthotopic Mainz Pouch (Mainz III))
    • A, An isolated 10 to 15 cm of cecum in continuity with 20 to 30 cm of ileum are isolated.
    • B, The entire bowel segment is opened along the antimesenteric border. An appendectomy is performed. 
    • C, The posterior reservoir is closed by joining the opposing  three limbs together with a continuous running suture.
    • D, An antireflux implantation of the ureters through a submucosal tunnel is performed and stented.
    • E, A buttonhole incision in the dependent portion of the cecum is made to provide for the urethral anastomosis.
    • F, The reservoir is closed side to side with a cystostomy tube and the stents exiting.

    Image Upload 3
  11. Mainz Pouch types?
    Mixed Augmented Ileum and Zecum


    Mainz I - Ileocecal resorvoir cuteneous, one limb of W is not opened 

    Image Upload 4

    Mainz II - Sigma-rectum pouch, The colon is incised along the antimesenteric border for 6 cm proximal and distal to the rectosigmoid junction. The ureters are implanted in an antirefluxing fashion, and that portion of colon is then reconfigured and closed. This is done to create a rectosigmoid reservoir of lower pressure to protect the upper tracts. 

    • Mainz III - Ileocecal reservoir orthotopic, whole bowel opened
    • [@ Mainz I and II for non-orthotopic, Mainz III for orthotopic, remember the sequence how they are kept as chapters]
  12. What are the complications of the orthotopic neobladder? (TU 75,2)

    Early complications of orthotopic urinary diversions?
    Complications of radical cystectomy 

    • Urine leak 
    • - manage with percutaneous drainage and/or bilateral nephrostomy tube placement is preferable to open surgical repair. The later is extremely difficult during the first few weeks after the initial surgery and is likely to be complicated
  13. Late complications of orthotopic urinary diversions?
    Incontinence

    Urinary tract infection - asymptomatic bacteruria does not require treatment except for urease producing organism because of the propensity of stone formation 

    Ureteroileal or afferent limb obstruction

    Urethral stricture

    Upper tract and pouch stones - more common with Kock neobladder because of the used of surgical staplers. Stones are rare in Studer and Hautmann neobladders which are made entirely with absorbable suture. 

    Pouch Vaginal fistula - difficult to repair. Preveention measures include leaving the vagina intact whenever it is safe from an oncologic standpoint, careful watertight closreure of the vaginal cuff when it is opened and placement of the mental flap between the vagina and neobladder, secured to the perivaginal tissue on either side of the urethral anastomosis. Beyond the initial few weeks a pouch-vaginal fistula is unlikely to heal spontaneously or with catheter drainage or percutaneous nephrostomy tubes alone. Repair may be attempted transvaginally, although reported success varies 

    Pouch perforation - is rare in orthotopic diversion outlet resistance is usually low. CT cystogram is diagnostic. These patients should be managed with exploration and repair, although percutaneous drains has been described

    Other than incontinence, these complications tend to be less common in the orthotopic diversion than in continent cutaneous diversion, and many if not most can be managed by endoscopic procedures and rarely require open surgical revision
  14. Continent issues in orthotopic neobladder?
    Daytime continence develops gradually over 3-6 months

    Nocturnal continence may continue to improve beyond 12 months from surgery. Nighttime incontinence remains one of the most bothersome sequelae of neobladders, occurring in 7% to 70% of patients. Nocturnal incontinence after orthotopic  reconstruction results in part from the absence of neurologic feedback and sphincter detrusor reflex, as well as decreased sphincter tone at night. There is also initially an excess of urine production at night with an inability to concentrate the urine and a reversal of the normal antidiuretic effect of  nighttime dehydration because of secretion of water by the bowel mucosa, which decreases with time.

    In women, preservation of the uterus may significantly affect the functional results of neobladder reconstruction. 

    Decreased urethral sensitivity has been proposed as a potential factor contributing to urinary incontinence after radical cystectomy and orthotopic diversion. Conscious or unconscious sensation of urine leakage in the membranous urethra may normally produce either a reflex or voluntary contraction with increased tone of the external urethra. This may be impaired in some patients with an orthotopic  diversion. This reflex may also diminish with age and  contribute to gradually decreasing continence in some individuals after orthotopic reconstruction.

    Evaluation and management of urinary incontinence after orthotopic diversion should be delayed until the neobladder has had time to expand. This may take 6-12 months of surgery. UDS to ensure adequate adequate capacity without pressure waves. 

    • Treatment 
    • - transurethral injection of bulking agents 
    • - artificial urinary sphincter 
    • - Pubovaginal sling procedures more efffective than bulking agents in women
  15. Urinary retention after orthotopic urinary diversion?
    • Risk factors
    • - use of excessive intestinal length for the reservoir (>60 cm of ileum)
    • - use of prostate-sparing or nerve-sparing surgical procedures


    • Evaluation 
    • - rule out urethral anastomotic stricture or tumor recurrence 


    • Management 
    • - CISC 
    • - Pharmacological therapy not effective 
    • - Biofeedback training 
    • - In women, posterior prolapse of the pouch may contribute to  late retention, and posterior support by means of omental flaps and sacrocolpopexy has been advocated
    • -
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prem7777
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351971
Card Set
Three14 141 Orthotopic Urinary Diversion
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Diversion
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