- Email: [email protected]
Modified Ileal Conduit Stoma: Safety of Freeing the Mesenteric Edge of the Distal Part of Ileal Conduits
Modified Ileal Conduit Stoma: Safety of Freeing the Mesenteric Edge of the Distal Part of Ileal Conduits Mohamed M. Abdallah and Nabil K. Bissada* From the Faculty of Medicine, Menoufia University, Menoufia, Egypt, and University of Arkansas for Medical Sciences (NKB), Little Rock, Arkansas
Purpose: An ileal conduit is created in about half of all urinary diversions. Difficulties in constructing an abdominal stoma in morbidly obese patients can be challenging, especially if the patient has a short mesentery. Excessive traction on the mesentery in an attempt to pass the distal segment of ileum through the thick abdominal wall may result in ischemia of the whole segment blood supply. We evaluated the safety of freeing the terminal portion of the conduit from its mesentery to facilitate easy passage of the conduit through the abdominal wall and decrease the incidence of parastomal hernia. Materials and Methods: Five domestic pigs were used for this study. In each subject a 10 cm segment of ileum was isolated to form the ileal loop and bowel continuity was established. A 3 to 4 cm segment of the distal ileal loop was freed from its mesenteric blood supply. This segment of the loop was passed through the appropriate defect in the abdominal wall to the skin and an everted stoma was constructed. Postoperatively the animals were followed for 1 month and then sacrificed. The ileal loop with its mesentery and surrounding skin were harvested en bloc and sent for gross and histological examination. Results: Mean postoperative time was 30 days (range 29 to 32). No mortality or perioperative complications were recorded. All animals had an uneventful postoperative course until the scheduled time for specimen collection. At harvesting the stoma remained pink in all animals. Gross examination and calibration demonstrated no evidence of narrowing or stenosis. Histological examination revealed no ischemic changes. The mucosa of the entire ileal loop was uniform and healthy. Conclusions: Freeing the mesenteric edge of the ileal loop is safe. This finding has an important application for allowing easy construction of an ileal loop or continent cutaneous diversion stoma in morbidly obese patients. This finding is also applicable when constructing terminal ileostomy or colostomy stoma in select patients. Key Words: urinary diversion, ileum, swine, ileostomy, colostomy
ifficulties may be noted when creating an IC in obese patients. Passing the distal part of the IC with its fatty mesentery through the thick abdominal wall of morbidly obese patients can be challenging or even impossible if the patient has a short mesentery. However, excessive traction on the mesentery may result in ischemia of the whole segment blood supply with catastrophic results. IC is still performed by many urologists.1– 4 Currently IC accounts for about half of all urinary diversions.4 The IC requires the shortest length of bowel and exposes the mucosa to urine for a shorter time than continent diversion.4 However, ileal conduits have complications. In 1 series 66% of the patients had complications (mean 2.2 complications per patient, range 1 to 7).4 Stoma related complications are among the most common (24% of cases). Parastomal hernia is the most common of these complications, accounting for 56% of all stoma related complications. Other stomal complications include stomal stenosis in 25% of patients, recurrent bleeding and skin irritation in 19%.4 Parastomal hernias have been reported in 4.5% to 18% of patients with an
D
Submitted for publication November 30, 2006. Study received Institutional Animal Care and Use Committee approval. * Correspondence: Department of Urology, University of Arkansas for Medical Sciences, 4301 West Markham St., No. 540, Little Rock, Arkansas 72205-7199 (telephone: 501-686-5241; FAX: 501-6865277; e-mail: [email protected]).
0022-5347/07/1783-1113/0 THE JOURNAL OF UROLOGY® Copyright © 2007 by AMERICAN UROLOGICAL ASSOCIATION
IC.4,5 Of stoma related complications 78% occur within the first 5 years after surgery.4 Stomal stenosis is seen in 2% to 19% of cases.3,4 We evaluated the safety of freeing the terminal portion of the IC from its mesentery to facilitate easy passage of the IC through the abdominal wall defect and decrease the incidence of parastomal hernia.
MATERIALS AND METHODS Animals The Animal Use Protocol was approved by the Institutional Animal Care and Use Committee and all animals were treated in accordance with the Guide for the Care and Use of Laboratory Animals of the Research Council. Five domestic pigs with an average weight of 70 pounds (range 50 to 70) were used for this experiment. No bowel preparation was given. No animals were excluded.
Anesthesia A mixture of drugs (pig mix) consisting of Telazol®, ketamine and Rompun®. An intramuscular dose of 2 mg/kg was used to sedate the pigs. The animals were maintained on isoflurane gas via an endotracheal tube and anesthetic machine. Subsequently the animals were positioned supine with the operative field prepared and drapes applied (fig. 1).
1113
Vol. 178, 1113-1116, September 2007 Printed in U.S.A. DOI:10.1016/j.juro.2007.05.007
1114
MODIFIED ILEAL CONDUIT STOMA
FIG. 3. Stoma at end of operation
FIG. 1. Animal position on operating, and incision and stomal sites.
Surgical Technique A 10 cm long midline incision is made to the peritoneum. Exploration of the ileum is done and about 10 cm of small bowel are harvested after developing mesenteric windows to form the IC using a gastrointestinal anastomosis stapler. Bowel anastomosis is completed using the gastrointestinal anastomosis stapler. The isolated segment is opened at each end by excising the staple line. The IC is washed with saline. The distal portion (3 to 4 cm) of the isolated segment is freed from its mesenteric blood supply using 3-zero silk sutures (fig. 2). The stomal site is chosen on 1 side of the wound. The defect in the abdominal wall is created as in construction of an ileal loop in humans with excision of a circular skin
segment and cruciate incision in the rectus fascia through the rectus muscle, and posterior rectus sheath and peritoneum. The freed portion of the isolated intestinal segment is brought out through this defect in the abdominal wall. The distal edges of the IC are everted to create an everted stoma (fig. 3). The peritoneum is sutured to the protruding distal ileal loop at the peritoneal level with interrupted absorbable sutures. The abdominal wound is closed using polyglactin sutures.
Followup Animals were followed for 1 month (range 29 to 32 days) in cages in a standard laboratory environment. Feeding started 24 hours after surgery.6 The animals were followed for any signs of pain, such as teeth grinding, reluctance to move or walk, hopping rather than walking normally, shivers or quivers, ripples along the body, sitting hunched, spiky hair, whimpering or failure to eat. No analgesics were required after postoperative day 1.
Specimens After 1 month the stoma was inspected and calibrated with the animals under anesthesia (fig. 4). A circumferential incision 1 cm away from the stoma was made. The peritoneum was entered and the ileal loop was harvested for pathological examination. Five sections through the ileal stoma, surrounding tissue and ileal loop were examined.
RESULTS
FIG. 2. Intraoperative devascularization of IC distal segment
Inspection revealed viable ileal loops in all animals. The stoma showed no signs of ischemia. Calibration of the stomas was done with the animals under anesthesia at harvesting. This demonstrated adequate caliber in all 5 animals, admitting a small finger. Histological examination of the specimens revealed that the conduits were adequately vascularized with no evidence of ischemia. One specimen showed infiltration of the submucosa with inflammatory cells, which might have been related to stomal environmental exposure (fig. 5).
MODIFIED ILEAL CONDUIT STOMA
1115
DISCUSSION Since the original description of the Bricker IC,1,7 there have been relatively few modifications.1,2 As addressed, creating the IC stoma can be difficult in obese patients. Passing the distal part of the IC with its fatty mesentery through the thick abdominal wall of morbidly obese patients can be challenging or even impossible if the patient has a short mesentery. Excessive traction on the mesentery may result in ischemia of the whole segment with catastrophic results. Mobilizing the right colon and root of the mesentery, and using a Turnbull stoma have been offered as alternatives. The characteristics that have led to the use of pigs for this experiment over other species for these models are related to the anatomical and physiological characteristics as well as the wound healing characteristics, which were reported to be similar to those of humans.8 In humans the arterial supply to the jejunum and ileum arises from the superior mesenteric artery. Branches divide as they approach the mesenteric border and extend between the serosal and muscular layers. From them numerous branches traverse the muscle, supplying it and forming an intricate submucosal plexus, from which minute vessels pass to the glands and villi.9 Although there is a profuse anastomotic network of arteries in the mesentery, anastomoses between the terminal branches close to the intestinal wall are few and alternate vessels are often distributed to opposite sides of the jejunum/ileum.10 In the Kock pouch several cm of small intestine are freed from the mesentery to create an intussuscepted valve.11–13 Studies with sigmoid colon demonstrated that blood flow to the tissue can extend beyond the site of vessel ligation.14 In another experiment with the sigmoid colon anastomosis after mesenteric artery ligation the integrity of the anastomosis depended mainly on residual blood flow to the anastomotic area.15 With this information we theorized that a segment of ileal loop cleared of its mesentery could survive with no risk of ischemia during long-term followup. In our work we used an operative technique similar to that used in humans except for freeing the distal segments of its mesenteric attachments.
FIG. 5. Histological examination of skin-intestine junction. Reduced from ⫻4.
In all 5 animals no stoma related complications were noted during this followup. Pathological examination of the specimen revealed no ischemic changes related to mesentery devascularization. Postoperative followup was 29 to 32 days. We believe that this period was enough to evaluate stomal viability, considering the relative life span of pigs vs that of humans. Domestic breeds typically weigh 100 kg by age 4 months.8 We believe that this information allows the construction of an IC or continent cutaneous urinary diversion in obese patients even if they have a short mesentery. However, problems with small vessels or other comorbidities that not infrequently exist in morbidly obese patients must be considered. We also believe that passing a mesentery devoid segment of bowel through the abdominal defect minimizes the risk of parastomal hernia compared to classic ileal conduits. We also believe that this finding is applicable to other intestinal surgeries, such as terminal ileostomy or colostomy and rectal pull-down, especially in the presence of a short mesentery. Applying the same principle may facilitate the fashioning of the intestinal anastomosis. Further studies are indicated to address these other issues. CONCLUSIONS This model demonstrates that freeing the mesenteric edge of the IC is safe. This finding has an important application for allowing easy construction of an IC or a continent cutaneous diversion stoma in morbidly obese patients. It may also minimize the incidence of parastomal hernia and it may be applicable in the construction of terminal ileostomy or colostomy stoma in such patients.
Abbreviations and Acronyms IC ⫽ ileal conduit REFERENCES FIG. 4. IC and stoma that can admit 1 finger with no stenosis after 1 month.
1.
Pannek J and Senge T: History of urinary diversion. Urol Int 1998; 60: 1.
1116 2.
3. 4.
5.
6.
7. 8.
MODIFIED ILEAL CONDUIT STOMA
Pagano S, Ruggeri P, Rovellini P and Bottanelli A: The anterior ileal conduit: results of 100 consecutive cases. J Urol 2005; 174: 959. Williams O, Vereb MJ and Libertino JA: Noncontinent urinary diversion. Urol Clin North Am 1997; 24: 735. Madersbacher S, Schmidt J, Eberle JM, Thoeny HC, Burkhard F, Hochreiter W et al: Long-term outcome of ileal conduit diversion. J Urol 2003; 169: 985. Wood DN, Allen SE, Hussain M, Greenwell TJ and Shah PJ: Stomal complications of ileal conduits are significantly higher when formed in women with intractable urinary incontinence. J Urol 2004; 172: 2300. Kaouk JH, Gill IS, Desai MM, Meraney AM, Fergany AF, Abdelsamea A et al: Laparoscopic orthotopic ileal neobladder. J Endourol 2001; 15: 131. Bricker EM: Bladder substitution after pelvic evisceration. Surg Clin North Am, 1950; 30: 1511. No ARS, Smith CP, Swindle MM and Smith AC: Information Resources on Swine in Biomedical Research. Beltsville, Maryland: United States Department of Agriculture, Agricultural Research Service, National Agricultural Library, Animal Welfare Information Center 2000.
9. 10.
11.
12.
13.
14.
15.
Krstic RV: Human Microscopic Anatomy: An Atlas for Students of Medicine and Biology. New York: Springer 2004. Standring S and Ellis H: Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 39th ed. New York: Elsevier 2005. Kock NG, Nilson AE, Nilsson LO, Norlen LJ and Philipson BM: Urinary diversion via a continent ileal reservoir: clinical results in 12 patients. J Urol 1982; 128: 469. deKernion JB, DenBesten L, Kaufman JJ and Ehrlich R: The Kock pouch as a urinary reservoir. Pitfalls and perspectives. Am J Surg 1985; 150: 83. Jonsson O, Olofsson G, Lindholm E and Tornqvist H: Longtime experience with the Kock ileal reservoir for continent urinary diversion. Eur Urol 2001; 40: 632. Kashiwagi H, Konishi F, Furuta K, Okada M, Saito Y and Kanazawa K: Tissue blood flow of the sigmoid colon for safe anastomosis following ligation of the inferior mesenteric artery. Nippon Geka Gakkai Zasshi 1994; 95: 504. Dworkin MJ and Allen-Mersh TG: Effect of inferior mesenteric artery ligation on blood flow in the marginal artery-dependent sigmoid colon. J Am Coll Surg 1996; 183: 357.
Purpose: An ileal conduit is created in about half of all urinary diversions. Difficulties in constructing an abdominal stoma in morbidly obese patients can be challenging, especially if the patient has a short mesentery. Excessive traction on the mesentery in an attempt to pass the distal segment of ileum through the thick abdominal wall may result in ischemia of the whole segment blood supply. We evaluated the safety of freeing the terminal portion of the conduit from its mesentery to facilitate easy passage of the conduit through the abdominal wall and decrease the incidence of parastomal hernia. Materials and Methods: Five domestic pigs were used for this study. In each subject a 10 cm segment of ileum was isolated to form the ileal loop and bowel continuity was established. A 3 to 4 cm segment of the distal ileal loop was freed from its mesenteric blood supply. This segment of the loop was passed through the appropriate defect in the abdominal wall to the skin and an everted stoma was constructed. Postoperatively the animals were followed for 1 month and then sacrificed. The ileal loop with its mesentery and surrounding skin were harvested en bloc and sent for gross and histological examination. Results: Mean postoperative time was 30 days (range 29 to 32). No mortality or perioperative complications were recorded. All animals had an uneventful postoperative course until the scheduled time for specimen collection. At harvesting the stoma remained pink in all animals. Gross examination and calibration demonstrated no evidence of narrowing or stenosis. Histological examination revealed no ischemic changes. The mucosa of the entire ileal loop was uniform and healthy. Conclusions: Freeing the mesenteric edge of the ileal loop is safe. This finding has an important application for allowing easy construction of an ileal loop or continent cutaneous diversion stoma in morbidly obese patients. This finding is also applicable when constructing terminal ileostomy or colostomy stoma in select patients. Key Words: urinary diversion, ileum, swine, ileostomy, colostomy
ifficulties may be noted when creating an IC in obese patients. Passing the distal part of the IC with its fatty mesentery through the thick abdominal wall of morbidly obese patients can be challenging or even impossible if the patient has a short mesentery. However, excessive traction on the mesentery may result in ischemia of the whole segment blood supply with catastrophic results. IC is still performed by many urologists.1– 4 Currently IC accounts for about half of all urinary diversions.4 The IC requires the shortest length of bowel and exposes the mucosa to urine for a shorter time than continent diversion.4 However, ileal conduits have complications. In 1 series 66% of the patients had complications (mean 2.2 complications per patient, range 1 to 7).4 Stoma related complications are among the most common (24% of cases). Parastomal hernia is the most common of these complications, accounting for 56% of all stoma related complications. Other stomal complications include stomal stenosis in 25% of patients, recurrent bleeding and skin irritation in 19%.4 Parastomal hernias have been reported in 4.5% to 18% of patients with an
D
Submitted for publication November 30, 2006. Study received Institutional Animal Care and Use Committee approval. * Correspondence: Department of Urology, University of Arkansas for Medical Sciences, 4301 West Markham St., No. 540, Little Rock, Arkansas 72205-7199 (telephone: 501-686-5241; FAX: 501-6865277; e-mail: [email protected]).
0022-5347/07/1783-1113/0 THE JOURNAL OF UROLOGY® Copyright © 2007 by AMERICAN UROLOGICAL ASSOCIATION
IC.4,5 Of stoma related complications 78% occur within the first 5 years after surgery.4 Stomal stenosis is seen in 2% to 19% of cases.3,4 We evaluated the safety of freeing the terminal portion of the IC from its mesentery to facilitate easy passage of the IC through the abdominal wall defect and decrease the incidence of parastomal hernia.
MATERIALS AND METHODS Animals The Animal Use Protocol was approved by the Institutional Animal Care and Use Committee and all animals were treated in accordance with the Guide for the Care and Use of Laboratory Animals of the Research Council. Five domestic pigs with an average weight of 70 pounds (range 50 to 70) were used for this experiment. No bowel preparation was given. No animals were excluded.
Anesthesia A mixture of drugs (pig mix) consisting of Telazol®, ketamine and Rompun®. An intramuscular dose of 2 mg/kg was used to sedate the pigs. The animals were maintained on isoflurane gas via an endotracheal tube and anesthetic machine. Subsequently the animals were positioned supine with the operative field prepared and drapes applied (fig. 1).
1113
Vol. 178, 1113-1116, September 2007 Printed in U.S.A. DOI:10.1016/j.juro.2007.05.007
1114
MODIFIED ILEAL CONDUIT STOMA
FIG. 3. Stoma at end of operation
FIG. 1. Animal position on operating, and incision and stomal sites.
Surgical Technique A 10 cm long midline incision is made to the peritoneum. Exploration of the ileum is done and about 10 cm of small bowel are harvested after developing mesenteric windows to form the IC using a gastrointestinal anastomosis stapler. Bowel anastomosis is completed using the gastrointestinal anastomosis stapler. The isolated segment is opened at each end by excising the staple line. The IC is washed with saline. The distal portion (3 to 4 cm) of the isolated segment is freed from its mesenteric blood supply using 3-zero silk sutures (fig. 2). The stomal site is chosen on 1 side of the wound. The defect in the abdominal wall is created as in construction of an ileal loop in humans with excision of a circular skin
segment and cruciate incision in the rectus fascia through the rectus muscle, and posterior rectus sheath and peritoneum. The freed portion of the isolated intestinal segment is brought out through this defect in the abdominal wall. The distal edges of the IC are everted to create an everted stoma (fig. 3). The peritoneum is sutured to the protruding distal ileal loop at the peritoneal level with interrupted absorbable sutures. The abdominal wound is closed using polyglactin sutures.
Followup Animals were followed for 1 month (range 29 to 32 days) in cages in a standard laboratory environment. Feeding started 24 hours after surgery.6 The animals were followed for any signs of pain, such as teeth grinding, reluctance to move or walk, hopping rather than walking normally, shivers or quivers, ripples along the body, sitting hunched, spiky hair, whimpering or failure to eat. No analgesics were required after postoperative day 1.
Specimens After 1 month the stoma was inspected and calibrated with the animals under anesthesia (fig. 4). A circumferential incision 1 cm away from the stoma was made. The peritoneum was entered and the ileal loop was harvested for pathological examination. Five sections through the ileal stoma, surrounding tissue and ileal loop were examined.
RESULTS
FIG. 2. Intraoperative devascularization of IC distal segment
Inspection revealed viable ileal loops in all animals. The stoma showed no signs of ischemia. Calibration of the stomas was done with the animals under anesthesia at harvesting. This demonstrated adequate caliber in all 5 animals, admitting a small finger. Histological examination of the specimens revealed that the conduits were adequately vascularized with no evidence of ischemia. One specimen showed infiltration of the submucosa with inflammatory cells, which might have been related to stomal environmental exposure (fig. 5).
MODIFIED ILEAL CONDUIT STOMA
1115
DISCUSSION Since the original description of the Bricker IC,1,7 there have been relatively few modifications.1,2 As addressed, creating the IC stoma can be difficult in obese patients. Passing the distal part of the IC with its fatty mesentery through the thick abdominal wall of morbidly obese patients can be challenging or even impossible if the patient has a short mesentery. Excessive traction on the mesentery may result in ischemia of the whole segment with catastrophic results. Mobilizing the right colon and root of the mesentery, and using a Turnbull stoma have been offered as alternatives. The characteristics that have led to the use of pigs for this experiment over other species for these models are related to the anatomical and physiological characteristics as well as the wound healing characteristics, which were reported to be similar to those of humans.8 In humans the arterial supply to the jejunum and ileum arises from the superior mesenteric artery. Branches divide as they approach the mesenteric border and extend between the serosal and muscular layers. From them numerous branches traverse the muscle, supplying it and forming an intricate submucosal plexus, from which minute vessels pass to the glands and villi.9 Although there is a profuse anastomotic network of arteries in the mesentery, anastomoses between the terminal branches close to the intestinal wall are few and alternate vessels are often distributed to opposite sides of the jejunum/ileum.10 In the Kock pouch several cm of small intestine are freed from the mesentery to create an intussuscepted valve.11–13 Studies with sigmoid colon demonstrated that blood flow to the tissue can extend beyond the site of vessel ligation.14 In another experiment with the sigmoid colon anastomosis after mesenteric artery ligation the integrity of the anastomosis depended mainly on residual blood flow to the anastomotic area.15 With this information we theorized that a segment of ileal loop cleared of its mesentery could survive with no risk of ischemia during long-term followup. In our work we used an operative technique similar to that used in humans except for freeing the distal segments of its mesenteric attachments.
FIG. 5. Histological examination of skin-intestine junction. Reduced from ⫻4.
In all 5 animals no stoma related complications were noted during this followup. Pathological examination of the specimen revealed no ischemic changes related to mesentery devascularization. Postoperative followup was 29 to 32 days. We believe that this period was enough to evaluate stomal viability, considering the relative life span of pigs vs that of humans. Domestic breeds typically weigh 100 kg by age 4 months.8 We believe that this information allows the construction of an IC or continent cutaneous urinary diversion in obese patients even if they have a short mesentery. However, problems with small vessels or other comorbidities that not infrequently exist in morbidly obese patients must be considered. We also believe that passing a mesentery devoid segment of bowel through the abdominal defect minimizes the risk of parastomal hernia compared to classic ileal conduits. We also believe that this finding is applicable to other intestinal surgeries, such as terminal ileostomy or colostomy and rectal pull-down, especially in the presence of a short mesentery. Applying the same principle may facilitate the fashioning of the intestinal anastomosis. Further studies are indicated to address these other issues. CONCLUSIONS This model demonstrates that freeing the mesenteric edge of the IC is safe. This finding has an important application for allowing easy construction of an IC or a continent cutaneous diversion stoma in morbidly obese patients. It may also minimize the incidence of parastomal hernia and it may be applicable in the construction of terminal ileostomy or colostomy stoma in such patients.
Abbreviations and Acronyms IC ⫽ ileal conduit REFERENCES FIG. 4. IC and stoma that can admit 1 finger with no stenosis after 1 month.
1.
Pannek J and Senge T: History of urinary diversion. Urol Int 1998; 60: 1.
1116 2.
3. 4.
5.
6.
7. 8.
MODIFIED ILEAL CONDUIT STOMA
Pagano S, Ruggeri P, Rovellini P and Bottanelli A: The anterior ileal conduit: results of 100 consecutive cases. J Urol 2005; 174: 959. Williams O, Vereb MJ and Libertino JA: Noncontinent urinary diversion. Urol Clin North Am 1997; 24: 735. Madersbacher S, Schmidt J, Eberle JM, Thoeny HC, Burkhard F, Hochreiter W et al: Long-term outcome of ileal conduit diversion. J Urol 2003; 169: 985. Wood DN, Allen SE, Hussain M, Greenwell TJ and Shah PJ: Stomal complications of ileal conduits are significantly higher when formed in women with intractable urinary incontinence. J Urol 2004; 172: 2300. Kaouk JH, Gill IS, Desai MM, Meraney AM, Fergany AF, Abdelsamea A et al: Laparoscopic orthotopic ileal neobladder. J Endourol 2001; 15: 131. Bricker EM: Bladder substitution after pelvic evisceration. Surg Clin North Am, 1950; 30: 1511. No ARS, Smith CP, Swindle MM and Smith AC: Information Resources on Swine in Biomedical Research. Beltsville, Maryland: United States Department of Agriculture, Agricultural Research Service, National Agricultural Library, Animal Welfare Information Center 2000.
9. 10.
11.
12.
13.
14.
15.
Krstic RV: Human Microscopic Anatomy: An Atlas for Students of Medicine and Biology. New York: Springer 2004. Standring S and Ellis H: Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 39th ed. New York: Elsevier 2005. Kock NG, Nilson AE, Nilsson LO, Norlen LJ and Philipson BM: Urinary diversion via a continent ileal reservoir: clinical results in 12 patients. J Urol 1982; 128: 469. deKernion JB, DenBesten L, Kaufman JJ and Ehrlich R: The Kock pouch as a urinary reservoir. Pitfalls and perspectives. Am J Surg 1985; 150: 83. Jonsson O, Olofsson G, Lindholm E and Tornqvist H: Longtime experience with the Kock ileal reservoir for continent urinary diversion. Eur Urol 2001; 40: 632. Kashiwagi H, Konishi F, Furuta K, Okada M, Saito Y and Kanazawa K: Tissue blood flow of the sigmoid colon for safe anastomosis following ligation of the inferior mesenteric artery. Nippon Geka Gakkai Zasshi 1994; 95: 504. Dworkin MJ and Allen-Mersh TG: Effect of inferior mesenteric artery ligation on blood flow in the marginal artery-dependent sigmoid colon. J Am Coll Surg 1996; 183: 357.