Ileus

Ileus, or intestinal paralysis, represents delay in coordinated bowel activity and is experienced by most patients following an intraperitoneal procedure but can also be exhibited following extraperitoneal procedures. This condition falls on a continuum from a normal physiologic process of recovery to a prolonged delay in bowel motility and function and is characterized by abdominal distention, decrease in bowel sounds, delayed passage of flatus and defecation, and accumulation of gas and fluids in the bowel that may result in nausea and vomiting. Prolonged ileus lengthens the patient’s discomfort, increases the need for parenteral nutritional support, and constitutes the most common reason for the delayed discharge after abdominal surgery occurring in 10–22% of patients undergoing major abdominal surgery. The economic impact of ileus in the United States is estimated to be $750 million to $1 billion annually.

Following abdominal surgical procedures, each section of the GI tract recovers at a different rate. The small intestine first regains function within 24 hours, the stomach in 24 to 48 hours, and the colon in 3 to 5 days. Therefore once the patient has experienced flatus following an operation, it is likely that the colon and the remaining GI tract have recovered.

The pathophysiologic mechanism of ileus is incompletely understood but appears multifactorial, involving neurogenic, inflammatory, and pharmacologic mechanisms. Neurogenic hypotheses suggest ileus may be a result of activation of a spinal reflex that inhibits GI motility, which is further reinforced through sympathetic hyperactivity induced by the stress of surgical trauma. For this reason, epidural/spinal anesthesia has been suggested to prevent prolonged ileus but must be adequately proximal to block the sympathetic chain and should utilize local anesthetics rather than narcotic agents to maximize effectiveness. Narcotic medication, frequently used in the perioperative setting, contributes to prolonged ileus through activation of µ-opioid receptors in the GI tract.

Electrolyte disturbances including hypomagnesemia, hyponatremia, and hypokalemia have all been cited as contributing to prolonged ileus. Additional contributors include prolonged operative time, significant manipulation of the bowel, increased blood loss, and body mass index. Inflammation is thought to contribute to postoperative ileus as a systemic response to surgery as well as due to direct manipulation of the bowel through both the innate and adaptive immune system and is the subject of research to identify pharmacologic interventions that may reduce its duration. It may be that the benefit in terms of shorter duration of ileus with laparoscopy compared to open surgery despite average longer operating times is due to the induction of less inflammation through a smaller degree of manipulation and/or improved temperature and humidity control of the bowel.

Several abnormalities common in urologic procedures can initiate and propagate ileus. Ileus can also be a sign of a more severe condition, and urologic patients experiencing a prolonged return of bowel function should be assessed for sources of electrolyte abnormalities and infection including intraabdominal abscess, bowel leak, urinary tract infection or leak, and urinoma. If any of these conditions are identified, correction is necessary to aid in the resolution of ileus and to prevent further development of complications. Finally, the acute withdrawal or accelerated taper of steroids in the postoperative period has been shown to prolong or even precipitate ileus and is corrected with bolus steroid administration.

In some patients, ileus may continue despite best efforts at prevention and treatment, and the mainstay of treatment remains nasogastric decompression. It is not our routine practice to surgically intervene in the setting of prolonged ileus when bowel obstruction and other inciting conditions have been ruled out or otherwise addressed. While the use of routine nasogastric decompression for abdominal procedures has fallen out of favor due to increased rates of pulmonary complications such as fever, atelectasis, and pneumonia as well as higher rates of wound complications and prolonged hospital length of stay, if the patient does become distended or experiences severe nausea or vomiting, a nasogastric tube should be placed.

Parenteral nutrition should be started if it is anticipated that prolonged ileus will continue (>7–10 days). Once bowel obstruction has been ruled out and the correctable abnormalities have been addressed, a trial of prokinetic agents may be considered; although, while this route may be potentially helpful for symptomatic relief of nausea, their use has not been consistently shown to reduce time of ileus.

Prevention of prolonged postoperative ileus remains a critical component of the management of the urologic patient. Minimization of narcotics with substitution/addition of nonsteroidal antiinflammatory medications (NSAIDs) or epidural, spinal, or regional (e.g., On-Q) local anesthetics has been shown to have beneficial impact on ileus. Perioperative use of peripheral µ-receptor antagonists (e.g., alvimopan) also reduces the time of postoperative ileus and may represent a cost-effective strategy. Other proven strategies include early enteral feeding, chewing sugar-free gum, early administration of coffee, electroacupuncture, and readaptation of the peritoneum after cystectomy and pelvic lymphadenectomy. Early postoperative ambulation may not expedite GI tract function recovery but is encouraged for benefits in reducing thromboembolism and pulmonary complications. Enhanced recovery protocols (standardized clinical pathways) that incorporate some or all of these strategies have shown significant reductions in hospital stays without increasing perioperative complications or readmissions.

Bowel Preparation

Considerable debate continues on the value of preoperative mechanical and/or antibiotic bowel preparation for the prevention of bowel-related complications. Dogma in favor of bowel preparation has been around for over 50 years and was challenged more recently with several trials and a Cochrane review suggesting no advantage for colectomy in terms of bowel anastomosis leaks, deep abscess, or superficial surgical-site infection and with possible worsening with prolonged ileus. Largely based on these data, several enhanced recovery protocols have eliminated routine use of bowel preparation for radical cystectomy patients. Additional data suggest it can be safely eliminated with radical prostatectomy. However, recent retrospective studies now suggest mechanical preparation along with enteral antibiotic preparation reduces infectious complications, anastomotic leak, and ileus in patients undergoing colectomy. It is unknown whether these data translate to urologic patients undergoing surgical manipulation of small bowel rather than colon.

Bowel Injury

Any procedure in or near the abdomen risks inadvertent bowel injury with reports after cystectomy, laparoscopy, percutaneous nephrolithotomy, suprapubic tube placement, and even transvaginal surgery. A simple serosal injury should be oversewn with Lembert-type suture, usually 3-0 silk. If the bowel is perforated, the approach varies depending on the size and location of the injury as well as whether the injury involved electrocautery. When the majority of the circumference of the bowel is violated the segment does not appear viable, or if the injury was caused by electrocautery, segmental resection should be performed. The small bowel can usually be reconnected safely. The large bowel can also often be reconnected, as long as fecal impaction or spillage is minimal.

If the bowel is perforated but the perforation does not appear to involve a large segment or circumference, primary repair in two layers with an inner layer of 3-0 polydioxanone (PDS) and an outer layer of interrupted 3-0 silk suture can be used. Closing the injury transverse to the longitudinal axis of the bowel should be considered so that the luminal diameter is not compromised. One may consider proximal bowel diversion if the patient is immunocompromised, has poor nutritional status, has had prior radiation of the involved segment, or there is gross contamination by colonic contents.

Delayed recognition of bowel injury typically presents with prolonged ileus, abscess (contained leak), or intraperitoneal sepsis (uncontrolled leak), and these patients can be profoundly ill. Initial presentation after laparoscopy is often more subtle, and patients may simply demonstrate pain at a single trocar, abdominal distention, diarrhea, and leukopenia. Surgical exploration and washout are indicated in patients with uncontrolled leak to gain source control and generally requires proximal diversion of the bowel. Consultation with general or colorectal surgery is often recommended in this setting to assist with bowel repair and diversion. Controlled leak (abscess) or retroperitoneal bowel injury in a patient who is otherwise stable may be successfully managed with percutaneous drainage.

Rectal injury represents a special case of bowel injury of specific interest to urologists. It has been reported in less than 1% of cases in modern prostatectomy series ( Fig. 11.1 ). Recognition of the injury is generally intraoperative with minimal spillage of rectal contents. In this case, primary closure in two or three layers with absorbable suture has been described without diverting colostomy in both open and laparoscopic/robotic series. A peritoneal or omental flap may be used to interpose between the repair and the urethra-bladder anastomosis. Fecal diversion should be more strongly considered in the setting of an immunocompromised patient or prior pelvic radiation. Recto-urethral fistula uncommonly develops after primary repair (2/16 in one series), management of which is discussed elsewhere in this text. Rectal injury during cystectomy can be managed similarly. However, avoidance of urinary diversion that will place suture lines directly over rectal repair should be considered. Delayed presentation of rectal injury, thought to be caused by thermal injury, typically presents with bloody stool or pneumaturia and is initially managed by washout and fecal diversion.

A, CT after radical prostatectomy showing large free air between bladder and rectum and lateral to the bladder in a patient with a rectal injury not recognized at the time of surgery requiring proximal diversion of bowel. B, Subsequent cystogram showing development of fistula between urethra and rectum.

Bowel Leak, Abscess, and Fistula

Procedures that require anastomosis of bowel segments, as are commonly performed in urology, risk development of bowel leakage. This can present in a variety of manners including enteric contents captured in drains, intrabdominal or pelvic abscess, or development of a fistula.

Leakage from bowel anastomosis after urologic surgery is rare. Patients may present with eneteric contents from a surgical drain, persistent ileus, leukocytosis, or fevers. Reoperation and repair may be considered in the early postoperative period. However, presentation of anastomotic leak has been reported over 30 days postoperatively, and reoperation after 7–10 days after the initial surgery is often very difficult due to edema and adhesions and is likely to result in additional harm. In this case, management focuses on control of the enteric contents through drainage and delayed surgical repair.

An intraabdominal abscess represents a walled-off infection and collection of bacteria, purulence, blood, and possibly enteric contents, urine, or foreign material. Most intraabdominal abscesses develop in the postoperative period and have been reported in 1.1% to 3.6% of patients after cystectomy with urinary diversion. The diagnosis should be suspected in a patient who is not progressing adequately following an operation. Ileus, abdominal distention, and anorexia are common symptoms. Spiking fevers are common but may be masked in immunosuppressed patients, in elderly patients, and in patients receiving antibiotics.

Diagnosis is made by ultrasound or CT scan ( Fig. 11.2 ). Treatment of the abscess requires drainage as antibiotics alone will not provide adequate resolution. For most intraabdominal, pelvic, and retroperitoneal abscesses, a percutaneous approach should be attempted before operative intervention. In general, a pigtail catheter should be left in the abscess cavity and removed when drainage has subsided. Catheter drainage also allows for additional management decisions including assessment for ongoing urine or bowel leakage as contributing factors. The indications for open surgical drainage include inability to safely drain due to location, failure of percutaneous drainage, or presence of interloop abscesses.

CT with IV contrast showing a subcutaneous abscess tracking from an intraabdominal location after radical cystectomy.

Antibiotic use should be directed by culture information until signs of infection have resolved. It is not necessary to continue antibiotics for long periods after adequate drainage. If the patient does not improve within 24 to 48 hours, additional imaging should be performed to ensure adequate drainage.

Fistula is defined as the abnormal communication between two structures and occurs not uncommonly in urologic surgery. Fistula to bowel used for urinary diversion occurs in up to 4% after radical cystectomy and between neobladder and vagina in up to 3.1%. Initial conservative management with maximal urinary drainage with an indwelling catheter and low residual diet may be undertaken. Surgical repair should not be undertaken in the acute setting due to the high risk for failure and potential to cause further injury. Surgical management principles when conservative management is not successful include (1) locating and excising the fistula tract, (2) closure of neobladder defect in two layers, and (3) interposition of healthy tissue with an omental flap. Temporary proximal diversion of bowel can also be utilized to maximize successful repair.

Vesicoenteric fistula, or the abnormal communication between bladder and bowel, is rare and most commonly occurs as a result of inflammatory and neoplastic processes of the bowel rather than as a result of urologic intervention. Management principles are similar to enterocutaneous fistula and include diversion of fluid crossing the fistula such as urine in a fistula to an ileal conduit. Patients often present with infection and may have undrained fluid collections leading to intraabdominal abscess that both require treatment.

Bowel Obstruction

Intraabdominal adhesions are the most common cause of bowel obstruction in the United States. The incidence of postoperative obstruction varies with the approach and procedure performed but is much less common. The short- and long-term risk of obstruction ranges from 1.6% to 16.0% after cystectomy and 5% for retroperitoneal lymph node dissection. Cases have been reported involving less invasive procedures including laparoscopy and even penile prosthesis placement.

Intestinal obstruction in the early postoperative period must be distinguished from ileus. Ileus is associated with many intraabdominal and extraabdominal processes that interfere with normal bowel motility and resolves spontaneously once the provoking source has been addressed.

Most patients with bowel obstruction exhibit abdominal pain, nausea, vomiting, obstipation, and abdominal distention. Delayed return of bowel function may also represent bowel obstruction. Pain is usually intermittent and may become constant if the bowel becomes compromised. However, pain severity may decrease over time as a result of bowel fatigue and atony. Patients usually become profoundly intravascularly depleted, manifested by orthostatic hypotension, tachycardia, and low urinary output. Eventually, patients manifest hypokalemic, hypochloremic metabolic alkalosis secondary to gastric loss of hydrogen and chloride and renal compensation of potassium wasting.

In patients with suspected bowel obstruction radiologic studies are indicated. Computed tomography (CT) scanning has sensitivity and specificity of >90% for small bowel obstruction ( Fig. 11.3 ). In addition, it is capable of detecting the cause as well as the presence of closed-loop obstruction and strangulation and therefore is usually the first radiologic examination performed. In contrast to ileus, which may also produce air–fluid levels, gas is not seen through the entire GI tract, especially distal to the point of obstruction.

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