Use of Intestinal Segments in Urinary Diversion By Dr.Turky Al-Mouhissen R3 at KKNGH

outline  General indications of urinary diversion  Intestinal segments used  General complications  Renal Function necessary for Urinary Diversion  Use of antireflux mechanism  Metabolic abnormalities associated  Neuromechanical Aspects

Indications for urinary diversion  Postcystectomy  Before transplantation in pt with bladder that cannot adequately receive the transplanted ureter  Dysfunctional bladders that result in  persistent bleeding  obstructed ureters  poor compliance with upper tract deterioration  inadequate storage with total urinary incontinence

What part of intestine can we use in urinary diversion?  Stomach  Small bowel  Ileum  Jejunum  Large bowel  Transverse  Sigmoid  Ileocecal

Use of stomach in diversion Advantages  decreased electrolyte abnormalities – (less permeable to urinary solutes)  acidifies the urine  produces less mucus  less stones  avoids acidosis ( has a net secretion of chloride and protons rather than absorption)  behaves urodynamically as other intestinal segments  less infection ( less incidence of bacteruria )  easy tunnelling of ureter  outside field of radiation

Disadvantages  less surgical familiarity  ulcers  hemmorrhage  dysuria/hematuria secondary to acid pH

complications  (Early )  gastric retention, hemorrhage, hiccups, pancreatitis, dudenal injury  (Late complications)  B12 anemia  iron deficiency anemia  uncontrollable metabolic alkalosis in patients with chronic renal failure   hematuria-dysuria syndrome  bilious vomiting  afferent loop syndrome  dumping syndrome  Note: many of these complications are related to the Bilroth 1 gastroduodenostomy

When to consider stomach? rarely indicated and may carry with them difficult problems of stomal maintenance  when use of other intestinal segments would result in malabsorption  pts with much bowel irradiated  pts with multiple small and large bowel adhesion

Use of jejunum in diversion  usually not employed  has major electrolyte abnormalities  Mainly, Na, Cl, K metabolic aciodosis with azotemia

Indications  no other acceptable bowel for use  extensive radiation to the ileum  severe adhesions / inflammation of ileum and absence of large bowel

contraindications  severe bowel nutritional disorders  presence of another acceptable segment ( use as distal segment as possible if must use this diversion ) ( use as distal segment as possible if must use this diversion )

Use of ileum in diversion Advantages:  simplest type of conduit diversion  associated with fewest number of intraoperative & postop. complications  familiar  decreased bacteruria compared to colon  decreased stone compared to colon  decreased contractility  adequate length available  decreased mucous compared to colon

contraindications  pts with short bowel syndrome  inflammatory small bowel disease  those whose ileum has received extensive radiation, often as a consequence of prior radiation to a pelvic malignancy

Disadvantages  malabsorption (Vit B12, fat, lack of bile salt resorption)  often in radiated field  higher incidence of bowel obstruction compared to colon ( 10% vs. 4%)  difficulty in mobilization depending on mesentery  more difficult to do non refluxing ureteric reimplant  Cl metabolic acidosis

Use of a colon in diversion Advantages  easier to tunnel ureter  less post op bowel obstruction  ( larger diameter)  better mobility than ileum

Disadvantages  more bacteruria  more mucus  more stones  more infection  higher cancer rate ( ureterosigmoidostomy)

 Three types of colon conduits are commonly used:  transverse  Sigmoid  Ileocecal  The transverse colon  pts who received extensive pelvic irradiation  It is an excellent segment when an intestinal pyelostomy needed

 The sigmoid conduit  good choice in pts undergoing a pelvic exenteration who will have a colostomy ( no bowel anastomosis needed )  It allows nonrefluxing submucosal reimplantation  Precaution :  Extensive pelvic irradiation

ileocecal conduit  Provides long segment of ileum when long segments of ureter need replacement  advantage of providing colon for the stoma

Contraindications to the use of transverse, sigmoid, and ileocecal conduits include  inflammatory large bowel disease  severe chronic diarrhea

Complications associated with urinary diversion

 Complications in the use of ilial conduit not listed include:  hypertension  renal failure  decreased renal function  These complications in large part depend on the  concomitant procedure performed  the length of follow-up  status of the kidneys before diversion  Over the long term (20 years), 7% of patients have renal failure requiring dialysis, and 60% show morphological deterioration of the upper tracts

 After salvage cystectomy, complications are increased so that 1/3 pts have one of the early complications  The complication rate is increased in pts requiring renal transplantation

 Complications in the use of large bowel not listed include :  Chronic diarrhea  renal failure  renal deterioration

 Interestingly, early reports suggested a lower incidence of renal deterioration with colon conduits  Some more recent series suggest incidence of these complications is about the same  However, there appears to be  7.6% incidence of pyelonephritis  78% incidence of preservation of the upper tracts over the long-term

Renal Function necessary for Urinary Diversion  Renal function in urinary diversion is affected by:  type of urinary intestinal diversion created  time the urine is exposed to the intestinal mucosa  greater degree of renal function needed for continent diversions rather than conduit diversions

 patients with normal urinary protein and serum creatinine below 2.0 mg/dL do well with diversion  can do continent diversion if  urine osmolality of 600 mOsm/kg or greater in response to water deprivation  GFR > 35 mL/min  minimal proteinuria  achieve urine pH of 5.8 or less following ammonium chloride load

Use of antireflux mechanism in urinary diversion   In a group of pts who had nonrefluxing colon conduits   Anastomoses remained nonrefluxing had a lesser incidence of renal deterioration than those in whose the antireflux anastomosis failed  F/U for 9-20 years revealed that 79% (22 of 28 patients) of the refluxing renal units deteriorated, whereas only 22% (11 of 51 pts) of the nonrefluxing units deteriorated (Elder et al, 1979; Husmann et al, 1989) ElderHusmannElderHusmann

 Others reported in continent diversions, the majority of pts who experience reflux show upper tract dilatation and deterioration, whereas few show upper tract deterioration when a nonrefluxing anastomosis is present (Kock et al, 1978) Kock  If a nonrefluxing mecahnism is used, only 7% of the renal units show evidence of pyelonephritic scarring after 3 months,  whereas if a refluxing anastomosis is constructed, 83% of the renal units show scarring. Half the conduits in both groups have significant bacteriuria (Richie and Skinner, 1975) Richie

 Others have not found the same high incidence of renal deterioration associated with ureteral intestinal reflux  One group noted no difference in the incidence of renal deterioration regardless of whether the colon conduit experienced reflux  17% (5 of 29) of nonrefluxing renal units showed deterioration compared with 18% (5 of 27) of refluxing units (Hill and Ransley, 1983) Hill  In another series, only 3 of 135 renal units with refluxing ureteral intestinal anastomoses that were unobstructed showed evidence of renal deterioration (Shapiro et al, 1975) Shapiro

 It does not appear that conduit pressures are transmitted to the renal pelvis  The pressure within the renal pelvis in refluxing diversions is not elevated above normal, and it is independent on the segment of bowel used (Magnus, 1977; Kamizaki and Cass, 1978; Hayashi et al, 1986) MagnusKamizakiHayashiMagnusKamizakiHayashi  Peristaltic ureteral contractions apparently dampen pressure transmission from intestine to renal pelvis, emphasizing the importance of normal ureters

 The voiding pressure is blunted by the distensible bowel segment  Moreover, in renal function measured 2 to 5 years postoperatively, there is no difference in ileal and colon conduits between those who experience reflux and those who do not (Mansson et al, 1984) Mansson  The successful creation of an antirefluxing anastomosis does not prevent bacterial colonization of the renal pelvis

Metabolic complications of the use of intestinal segment in diversion (1) electrolyte abnormalities (2) altered sensorium (3) abnormal drug metabolism (4) osteomalacia (5) growth retardation (6) persistent and recurrent infections (7) formation of renal and reservoir calculi (8) short bowel & nutritional problems (9) development of urothelial / intestinal cancer

 Many of these complications are a consequence of altered solute absorption across the intestinal segment  The factors that influence the amount of solute and type of absorption are  segment of bowel used  surface area of the bowel  amount of time the urine is exposed to bowel  concentration of solutes in the urine  renal function  pH of the fluid

Electrolyte abnormalities Stomach :  Cl, K metabolic alkalosis  HCl secretion by gastric segment is coupled with systemic HCO3 release  The renal HCO3 excretion ( compensation ) is impaired in persons with compromised renal function & exacerbate alkalosis  This is generally not a significant problem unless the patient has concomitant renal failure

 Rx of metabolic abnormalities with the use of stomach in urinary diversion:  electrolyte disorder may be difficult to treat  Proton pump blockers (omeprazole)  Histamine ( H2 ) receptor blocker  but often when this occurs, the segment must be taken down and replaced with ileum or colon

Electrolyte abnormalities Jejunum  Na, Cl, K, azotemia, and metabolic acidosis particularly when proximal jejunum is used  incidence varies 25% - 75% pts  Severe abnormalities may occur in 4% when short segments are employed

mechanism  jejunal segment loses NaCl ( secretes) and reabsorbs K & H  Na and Cl carry water with it which leads to dehydration  dehydration results in hypovolemia  renin increased as is aldosterone  Na reabsorbed by kidney and K lost  when this urine is presented to the jejunal segment, a favorable concentration gradient exists for loss of Na and increased reabsorbtion of K (Na rich, K poor urine)

HCO3+H H2O+CO2

Symptoms  lethargy  nausea and vomiting  dehydration  muscle weakness  elevated temp  made worse if on TPN ( mechanism unclear)  worse with more proximal segments of jejunum

treatment  rehydration with Na Cl  correction of acidosis with Na HCO3  Provided that renal function is normal, hyperkalemia is corrected by renal secretion  A diuretic may be helpful to correct the hyperkalemia  After restoration of normal electrolyte balance, long-term therapy involves oral supplements with sodium chloride  A thiazide diuretic has also been useful in selected cases to control hyperkalemia over the long term

Electrolyte abnormalities ileum & colon   Cl metabolic acidosis, +/- hypokalemea   Acidosis occurs in most pts but in minor degree   Hyperchloremic acidosis has been reported with a frequency of 68%   (19 of 28 pts—10 of 19 cases were severe enough to require treatment) in pts with ileal conduits (Castro and Ram, 1970)Castro   In another study, 70% of patients with ileal conduits followed for 4 years or more had a decreased serum bicarbonate level (Malek et al, 1971)Malek   Severe electrolyte disturbances occur to a much lesser degree   reported to be major problem in 18% (8 of 45) of pts with intestinal cystoplasties (Whitmore and Gittes, 1983)Whitmore   in 10% (17 of 178) of patients with ileal conduits (Schmidt et al, 1973)Schmidt   in 80% (112 of 141) of patients with ureterosigmoidostomies

mechanism  Due to the ionized transport of ammonium  ammonium substitutes for Na in the Na/H antiport  exchange of NH4 for H+ is coupled with the exchange of Cl for HCO3  ammonium chloride is absorbed across the intestinal lumen in exchange for carbonic acid ( CO2 + H20)

CO2+H2O H+HCO3

hypokalemea  more common in ureterosigmoidostomies   In one study,   pts with ureterocolonic diversions had a 30% reduction in total body K,   those with ileal conduits had no significant alteration in total body K; individually   some had 14% reduction in total body K (Williams et al, 1967)Williams

 The K depletion is due to renal K wasting as a consequence of  renal damage  osmotic diuresis  loss through intestinal secretion   it has been shown that when exposed to high concentrations of K in the urine, ileal segments reabsorb some of the K, whereas colon is less likely to do so (Koch et al, 1990)Koch   Rx must involve both replacement of K and correction of the acidosis with HCO3

Symptoms  fatigability  anorexia  weight loss  polydipsia  Lethargy  Flaccid paralysis in case of severe hypokalemea  Those with ureterosigmoidostomies also have an exacerbation of diarrhea

treatment  alkalinizing agents ( sodium bicarbonate, potassium citrate)  chlorpromazine or nicotinic acid  They inhibit cAMP and thereby impede Cl transport  Used in pts in whom persistent hyperchloremic metabolic acidosis occurs and in whom excessive Na loads are undesirable  These agents used alone do not correct the acidosis in humans, but they limit its development and thus reduce the need for alkalinizing agents

Metabolic abnormalities  Water deprivation test for renal function is inappropriate test in diversion  Bcs the bowel transports solutes and its membrane is not particularly watertight, osmolality generally re-equilibrates across the bowel wall  The bowel also makes the contents more alkaline impossible to determine the ability of the kidney to acidify simply by measuring urinary pH in pts with urinary intestinal diversion impossible to determine the ability of the kidney to acidify simply by measuring urinary pH in pts with urinary intestinal diversion  As urea and creatinine are reabsorbed by both the ileum and the colon, serum concentrations of urea and creatinine do not necessarily accurately reflect renal function

Altered Sensorium causes  Altered ammonium metabolism (most common)  Magnesium deficiency  Drug intoxication  Amoniagenic coma  Cirrhotics  Abn. liver function without cirrhosis  Normal hepatic function Most common with ureterosigmoidostomy

Treatment  draining intestinal diversion to prevent exposure of bowel to urine ( Foley or rectal tube (if ureterosig)  Neomycin po to reduce ammonia load  decrease protein intake  lactulose P.O or P.R ( complexes ammonia and prevents absorption)  IV Arginine glutamate 50 g in 1 Litre D5W (in severe cases)

Abnormal Drug absorption  Drug intoxication has been reported in pts with diversions  Drugs more likely to be a problem are those that are absorbed by the GI and excreted unchanged by the kidney  The excreted drug is re-exposed to the intestinal segment, which then reabsorbs it, and toxic serum levels develop  Reported for phenytoin & antimetabolites (methotrexate)  in pts with continent diversions who are receiving chemotherapy, consideration should be given to draining the pouch during the period of time the toxic drugs are being administered

Osteomalacia ( renal rickets)  mineralized bone is reduced and osteoid component becomes excessive Causes:  acidosis ( excess protons are buffered by the bone with release of bone calcium)  correction of acidosis results in remineralization  Vit D resistance ( renal in origin)  excessive calcium loss by the kidney

Growth and Development  urinary intestinal diversion has a detrimental effect on growth and development  In a study of 93 myelodysplasia pts followed for 17 to 23 years, significant aberrations in growth were noted when morphometric parameters were analyzed  Anthropomorphic measurements in those with urinary intestinal diversion showed a decrease in linear growth in all indices measured, with a statistically significant decrease in biachromial span and in elbow-hand length (Koch et al, 1992) Koch  patients are more prone to fractures and complications after orthopedic procedures

Infection   increased incidence of bacteruria, bacteremia and sepsis   many patients do well with chronic bacteruria   pts with Proteus or Pseudomonas are more likely to deteriorate their upper tracts, therefore those with pure cultures of one of these organisms should be treated   pts with mixed cultures may generally be observed, provided that they are Asymptomatic

Stones  ** #1 stone calcium ammonium magnesium phosphate Factors:  hyperchloremic metabolic acidosis  preexisting pyelonephritis  UTI with urea splitting organisms  Staples Incidence:  continent cecal resevoirs (koch) 20%  colon conduit 4%  ileal conduit 10-12%

Short bowel and Nutritional Problems   B12 malabsorptioon   bile salt malabsorption   loss of Ileocecal valve  bacterial growth in ileum  B12, bile salt, fat malabsorption   jejunal loss -- > malabsorption of Ca folic acid and fat

Cancer   ureterosigmoidostomy   11% risk   year delay   histologically:   adenocarcinoma   adenomatous polyp   sarcoma   TCC   cause: transitional epithelium in contact with colonic epithelium and both are exposed to urine and feces   routine colonoscopy in these patients

neuromechanical aspects Volume pressure  goal  create a sphere, with high volume  over time if conduit is filled its volume will increase Laplace’s Law  for a sphere, tension of wall is proprtional to radius X pressure  The greater the radius, the smaller the pressure which is desirable to prevent upper tract deterioration Motor activity  detubularizing bowel interrupts coordinated motor activity for at least 3 months, eventually returns to N state  persistaltic waves are thought to reappear  reconfiguring bowel increase volume

REFFERENCES  The Journal Of Urology, Vol. 161, , April 1999  Urologic Clinics of North America, Vol. 24, No. 4, Nov  Campbell`s Urology, 8 th Edition, 2002