In this chapter, the surgical technique for constructing an ileal orthotopic bladder substitute combined with an afferent tubular segment is described. This reservoir with a low pressure and high compliance is continent, while preserving renal function and pertaining a low risk of fluid and electrolyte imbalances. The length of ileum resected is relatively short, and because both the terminal ileum and ileocecal valve are left in situ, the risk of malabsorption and diarrhea is limited. Another bonus is the ease of surgery; this operation can be done by every urologist experienced in performing radical cystectomy with an ileal conduit.
Low pressure is achieved by double folding the ileum, which is transected along its antimesenteric border, to form a spherical reservoir, thereby rendering contractions of the bowel wall asynchronous and uncoordinated. Because the reservoir is spherical, the maximum capacity and lowest possible pressure for the given surface of bowel is obtained. As illustrated by Laplace’s law (Pressure = Tension/Radius), intraluminal pressure is low for a given tension because conversion of a tubular structure into a spherical reservoir increases the radius. Furthermore, the spherical shape achieves maximal capacity, and the surface-to-volume ratio minimizes the reabsorbing surface and consequently the associated metabolic issues.
The 12- to 14-cm-long afferent tubular limb allows the ureters to be resected at a safe oncologic distance from the bladder. The periureteral lymphatic tissue is included in the resection because it may harbor micrometastasis. In addition, by removing the distal ureter, ureteral ischemia is precluded and thereby subsequent stricture formation is prevented. Under normal physiological conditions, the segments isoperistaltic contractions decrease the possibility of ureteral reflux and transmission of reservoir pressures into the renal pelvis. An additional benefit is that if urethral recurrence or functional problems (e.g., incontinence, pelvic recurrence, inability to void) occur, the afferent limb can easily be converted into an ileal conduit.
As is true for all bladder substitutes, specific selection criteria must be fulfilled. Box 58.1 lists the contraindications for orthotopic ileal bladder substitution. Although an estimated glomerular filtration rate (eGFR) of 50 mL/min/m 2 is considered the lower limit, some patients with significant creatinine elevations due to primary bladder cancer may recover sufficient function to allow for continent diversion after the obstruction is relieved. In this situation, placement of a percutaneous nephrostomy tube before surgery may provide a better idea of true renal function. As with all bladder substitutes, cancer treatment is the primary goal of surgery and must not at any cost be compromised by the orthotopic reconstruction.
Urinary stress incontinence or cystoceles grade III or IV in female patients
A damaged lissosphincter or incompetent urethra (injury to autonomic nerves)
Impaired renal function (estimated glomerular filtration rate of <50 mL/min/m 2 )
Severely impaired liver function
Severe intestinal diseases (e.g., Crohn disease, short bowel syndrome)
Tumor infiltration of the distal prostatic urethra in men or the bladder neck in women
Unwillingness or incapability to adhere to regular postoperative follow-up
Previous radiation therapy or chronologic age should not be considered absolute contraindications for continent urinary diversion. Even octogenarians do not necessarily have to be excluded, but the time needed for postoperative recovery and for achieving urinary continence may be longer than in younger patients. A relatively weaker sphincter muscle because of old age is a possible explanation for this observation. The ileal orthotopic bladder substitute is also particularly well suited for patients in whom the consequences of ileocecal resection must be avoided.
Preoperative Patient Preparation
Patients follow a regular diet until the evening of surgery at which point they eat only a light meal. Bowel preparation consists of two enemas late in the afternoon the day before surgery. Neomycin–erythromycin and antegrade bowel preparations, which can increase the risk of fluid imbalance, are avoided. In older patients, fluid imbalance can cause cardiovascular instability because of intravascular volume depletion as well potentially placing the patient in a catabolic state before surgery.
All patients receive perioperative and postoperative prophylactic antibiotics. Subcutaneous heparin is injected in the upper arm the evening before surgery and continued postoperatively. To prevent deep venous thrombosis of the lower extremities or bronchopneumonia, patients wear compression stockings and are taught appropriate breathing exercises by a physical therapist.
Under general and epidural anesthesia, the latter placed for both intraoperative and postoperative pain management, the patient is placed in a dorsal Trendelenburg position with overextension of the pelvis for optimal intraoperative exposure. Under sterile conditions an 18-Fr urethral Foley catheter is inserted into the bladder. A lower midline incision gives adequate access for the surgery. The technique for radical cystectomy with bilateral pelvic lymphadenectomy has been described elsewhere. Previous publications refer in detail to the technique and role of nerve sparing, which should be attempted at least on one side and is an important step toward obtaining good functional results. In women, increasing attention is being placed on the role of nerve sparing. In a recent publication, preservation of the uterus and attempted nerve sparing were associated with better functional outcome.
For nerve-sparing cystectomy in male patients, the nerve fibers in the dorsomedial pedicles that are located lateral to the seminal vesicles in the angle between the seminal vesicle and the base of the prostate, as well as the paraprostatic neurovascular bundle have to be left intact. Nerve sparing can be facilitated by beginning along the prostate through a lateral approach with incision of the endopelvic and periprostatic fascia. Santorini plexus is bunched and ligated at the level of the prostate, not distal to it. The dorsolateral neurovascular bundle is then separated from the prostatic capsule (step 1, Fig. 58.1 ). Thereafter the dorsomedial bladder pedicle is divided anterolateral to the seminal vesicles. The dissection ends at the base of the prostate. The pelvic plexus lateral to the seminal vesicles is spared by gentle blunt dissection (step 2, Fig. 58.1 ). Dissection continues towards the angle between the seminal vesicle and the base of the prostate ventral to the neurovascular bundle (step 3, Fig. 58.1 ). After having preserved the pelvic plexus and the neurovascular bundle, the prostatic apex is approached from its lateral aspect directly along the prostatic capsule to avoid damage to the sphincter apparatus and the distal portion of the neurovascular bundle. Finally, the membranous urethra is sharply dissected out of the donut-shaped prostatic apex, and the specimen is removed.
For nerve sparing in women, the line of dissection should be ventrolateral to the cervix and along the anteroventral aspect of the vaginal wall, that is, at the 2 or 10 o’clock position ( Fig. 58.2 ). An empty sponge-holding forceps in the vagina facilitates dissection along the whitish vaginal wall. It is important to remain in close contact with the whitish wall of the vagina, thereby ensuring that the paravaginal venous plexus is ligated before the dorsomedial bladder pedicle is transected. The endopelvic fascia is disturbed as little as possible to minimize damage to the intrapelvic branch of the pudendal nerve, which contributes to urethral innervation. In general, nerve sparing should be performed on the non–tumor-bearing side and extensive surgery on the tumor-bearing side. Videos can be downloaded from the American Urology Association (AUA) or European Association of Urology (EAU) video library.
Preparation of the Ileal Segment for the Bladder Substitute
For the ileal bladder substitute, 52 cm to 56 cm of ileum, is isolated 25 cm proximal to the ileocecal valve ( Fig. 58.3 ). The ileocecal valve and the most distal 25 cm of the ileum are preserved to minimize the risk of malabsorption and bile acid–induced diarrhea. After completing the lymph node dissection, the peridural anesthesia is temporarily stopped to avoid increased bowel muscle tone and activity, which would result in an artificial shortening of the bowel and as a consequence removal of more bowel than necessary for construction of the reservoir. The segment of ileum designated for the bladder substitute is measured with a ruler along the mesoileum without overstretching the bowel.
The distal mesenteric division, which is important to achieve adequate mobility of the reservoir, should extend deep into the mesentery. The proximal mesenteric division, however, is short and assures a broad vascular blood supply to the bladder substitute by at least two separate vascular arcades. Bowel continuity is reestablished with a standard end-to-end seromuscular running (4-0 Vicryl) suture. The same technique is used to close both ends of the ileal segment, and the mesenteric gap is readapted. The proximal segment of the harvested ileum is left untouched to become the afferent tubular segment. The distal 40 cm to 44 cm that will form the reservoir is opened with scissors along the antimesenteric border ( Fig. 58.4 ).
The left ureter is mobilized to the level of the lower pole of the kidney. Care is taken to mobilize the periureteric tissue with the ureter to preserve its blood supply and prevent ischemia. The left ureter is then transferred retroperitoneally, crossing the aorta above the inferior mesenteric artery, to the right side of the abdomen. If the ureters need to be resected closer to the kidney (e.g., carcinoma in situ, compromised vascular supply, previous radiation history), a longer afferent ileal segment can be harvested to bridge the necessary distance.
The ureters are anastomosed, using the Nesbit technique, in an end-to-side fashion to the proximal isoperistaltic (nonincised) afferent tubular segment and placed paramedial to the antimesenteric border ( Fig. 58.5 ). To prevent bowel ischemia between the ureteral implantation sites, the right ureter is placed approximately 1 cm distal to the left one.
After spatulating the ureters over a length of 1.5 to 2 cm, a suture (4-0 polyglycolic acid) is placed through both ends of the spatulated ureter and the ileal incision. A running suture beginning at the proximal end of the ureter and encompassing a minimal amount of the ureteral wall and the seromuscular layer of the ileum is placed on one side. A minimal amount of the ureter is taken in the corner or proximal end to avoid narrowing the ureter. As the suture is completed, the amount of ureteral wall tissue incorporated gradually is increased to stabilize the anastomosis.
To preclude a fistula resulting from ureteral mucosal prolapse and to establish a watertight anastomosis, care should be taken to have the ureteral wall lie between the mucosa and seromuscularis of the bowel. This is accomplished by starting each stitch on the ureteral wall. Before suturing the other side of the ureter, an 8-Fr ureteral catheter is placed and secured with 5.0 Rapid Vicryl through the wall of both the ureter and the stent. It is loosely tied to prevent ischemia. Tension on the anastomosis is reduced with three interrupted sutures placed between the distal periureteral tissue and the ileal afferent tubular segment. By doing so, the periureteral tissue also covers the suture line. The stents are then passed through an area of the distal tubular wall that is covered with mesenteric fat. This helps prevent leakage at the time of removal (see Fig. 58.5, C ).
Construction of the Bladder Substitute
The previously opened portion of the ileal segment is folded into a U shape, and the two medial borders are adapted with a running seromuscular 2.0 Vicryl suture (see Fig. 58.5, C ). The bottom of the U is then folded up between the two ends of the U to create a spherical, low-pressure reservoir with an initial capacity of approximately 120 mL ( Fig. 58.6 ). Before reservoir closure, the surgeon’s forefinger is introduced to determine the most dependant portion, and a 1-cm-diameter hole is excised from the wall as shown in Fig. 58.7 . Although it may appear easier to use the funnel-shaped end of the reservoir, this should be avoided because the risk of kinking and obstruction at the anastomotic site is increased, especially when the reservoir is full ( Fig. 58.8 ). To obtain optimal voiding and emptying, the anastomosis should sit broadly on the pelvic floor.