Traumatic and iatrogenic bladder injury

INTRODUCTION — Injuries to the bladder are relatively uncommon, occurring in approximately 1.6 percent of blunt trauma [1]. Injuries can occur due to blunt trauma, penetrating trauma, or iatrogenic means. The majority of traumatic bladder injuries are extraperitoneal, which can often be managed nonoperatively.

The clinical features, diagnosis, and management of traumatic and iatrogenic bladder injuries are reviewed here. (See "Overview of traumatic lower genitourinary tract injury" and "Traumatic injury to the male anterior urethra, scrotum, and penis" and "Posterior urethral injuries and management".)

ANATOMY AND MECHANISM OF INJURY — The urinary bladder is a hollow organ located near the pelvic floor, posterior to the pubic symphysis and anterior to the vagina in women and rectum in men. The bladder is separated by a prevesical space named the space of Retzius. The peritoneal lining covers the bladder dome, which is the weakest part of the bladder and vulnerable to injury as the bladder distends with urine and rises into the peritoneal cavity.

The bladder receives urine from the kidney via the ureters (right and left), which enter the bladder inferiorly and posteriorly. Urine exits the bladder at the bladder neck. The right ureteral orifice, left ureteral orifice, and bladder neck delineate the bladder trigone.

Traumatic injury — The majority of traumatic bladder injuries have a blunt etiology (85 percent) [2-4]. Over one-half of traumatic bladder injuries occur as a result of a motor vehicle crash [5]. Direct trauma to a full bladder (eg, seatbelt) can rupture the bladder at its weakest part (ie, at the dome), causing urine to leak into the abdominal cavity [6,7]. Among penetrating injuries, gunshot wounds predominate (88 percent) [3].

Associated injuries — Because of the intimate association of the bladder with the pelvis, traumatic bladder injuries are highly associated with pelvic fracture, particularly pubic ramus fractures (95 percent) and obturator ring fractures [8,9]. Bladder injury associated with pelvic fractures is often due to intrusion of bony spicules directly into the bladder. While pelvic fractures are very common when bladder injuries are identified, bladder injuries occur in only approximately 3 percent of pelvic fractures [10].

With penetrating bladder injuries, there is low association with other injured organs (4 percent). Penetrating rectal injuries and buttock injuries are associated in 13 and 20 percent of these patients, respectively [1].

Iatrogenic injury — Iatrogenic bladder injuries are rare. Increasing age, recent chemotherapy or radiation, and smoking are the main risk factors for iatrogenic bladder injury [11]. In a national database review, the incidence was 0.11 percent of surgeries [11]. Iatrogenic bladder injury most commonly occurs following obstetric/gynecologic surgery (7.8/1000 cases), typically hysterectomy [1,12]. Among general surgery cases, open colorectal surgery is the most common etiology [11]. Iatrogenic bladder injury has also been reported following transurethral bladder tumor resection and with the surgical management of pelvic fractures [1].

CLINICAL PRESENTATIONS — Clinical findings that suggest the presence of a bladder injury include gross hematuria, suprapubic tenderness, and inability or difficulty voiding. Findings differ depending upon whether the bladder injury is intraperitoneal or extraperitoneal. (See 'Injury classification' below.)

Hematuria — Gross hematuria and/or a pelvic fracture are common findings in the setting of bladder trauma (90 and 88 percent, respectively) and, when present together, warrant evaluation for bladder injury. A meta-analysis that evaluated the combination of a pelvic fracture and gross hematuria found that bladder injury was present in 29 percent of the patients presenting with both. In the setting of microhematuria or normal urine and a pelvic fracture, bladder injury is less likely and was present in only 0.6 percent of patients in one review [13]. Microscopic hematuria combined with pelvic fracture is not an indication for radiologic evaluation but may be warranted in selected cases [14].

Gross or microscopic hematuria in the presence of penetrating injuries with pelvic trajectories also requires evaluation of the bladder, based on index of suspicion.

Suprapubic tenderness — Suprapubic tenderness is common but not specific given the common association with pelvic fracture or other injuries. Once the acute traumatic period has passed, any persistent suprapubic pain should raise suspicion for bladder injury. Delayed presentations, from days to years, have been documented [15-22].

Peritonitis — If the diagnosis of an intraperitoneal bladder injury is missed initially, irritation from leaking urine can lead to persistent abdominal pain, peritonitis, ileus, and possibly sepsis [15,19]. Symptoms may include low urine output, and increased blood urea nitrogen (BUN) and creatinine from peritoneal absorption of urine [14].

DIAGNOSIS — Although a diagnosis of bladder injury may be suspected based upon a clinical presentation of hematuria, particularly when associated with pelvic fracture, a definitive diagnosis requires either directly identifying the injury at the time of exploratory laparotomy or imaging the bladder (ie, cystography). Retrograde cystography identifies the presence of an injury and can determine if it is intraperitoneal or extraperitoneal. (See 'Injury classification' below.)

Intraoperative evaluation — For patients who have indications for immediate laparotomy and for whom cystography could not be obtained preoperatively, direct inspection of the bladder dome should be performed during exploratory laparotomy to identify intraperitoneal bladder rupture. If intraperitoneal bladder injury is identified, the remainder of the bladder should be examined via the bladder dome injury site for a concomitant extraperitoneal injury. If necessary, the bladder dome can be opened further to facilitate direct inspection. If further inspection is not possible due to the extent of other injuries or ongoing hemodynamic instability, cystography can be performed postoperatively to identify a potential extraperitoneal bladder injury.

Cystography — The combination of gross hematuria and pelvic fracture is an absolute indication for imaging the bladder [14,23]. Retrograde cystography can be accomplished using plain films, fluoroscopy, or computed tomography (CT). The choice of imaging technique depends upon the clinical status of the patient, radiologic capabilities, and physician preference. Plain film and CT cystography have similar sensitivity and specificity for bladder injury [24,25].

Retrograde urethrogram should be performed prior to cystography if a urethral injury is also suspected (blood at meatus, perineal hematoma, complex perineal laceration); however, retrograde urethrogram is not a substitute for cystography, which must be done to evaluate the bladder.

Retrograde cystography is performed by passively filling the bladder with water-soluble contrast media (eg, Cystografin, Isovue-300) via a urinary catheter to at least 300 mL [24,25]. If contrast media is still freely flowing after 300 mL has been instilled and the patient is not uncomfortable, continued filling (until discomfort is felt) is recommended to increase diagnostic sensitivity [26]. At least three films are necessary for static/plain films or fluoroscopy. These include anterior-posterior films at capacity, a lateral film at capacity, and a post-drainage film.

With CT cystography, filling of the bladder is similar with retrograde cystography but uses a dilute water-soluble contrast to prevent artifacts; however, the multiplanar capabilities of CT only require imaging at bladder capacity. It is important to note that allowing the bladder to fill antegrade following intravenous contrast administration is not an acceptable method to diagnose bladder injuries and will lead to missed injuries [24,25,27]. Although a bladder injury may be seen incidentally on routine standard CT scan, a retrograde cystogram should be performed to confirm the suspicion.

Differential diagnosis — Hematuria in the setting of traumatic injury can indicate injury to any part of the genitourinary tract (ie, kidney, ureter, bladder, urethra). For suspected renal trauma, a CT urogram is warranted in the setting of blunt abdominal trauma with gross hematuria, blunt abdominal trauma with microhematuria and systolic blood pressure <90 mmHg, penetrating abdominal trauma with any degree of hematuria, and pediatric abdominal trauma with any degree of hematuria. (See "Overview of traumatic upper genitourinary tract injuries in adults".)

Hematuria is not a reliable indicator for urethral injury. In the setting of concomitant pelvic fracture, posterior urethral injury may be the cause of hematuria. Straddle injuries to the anterior urethra can also result in hematuria. In both settings, retrograde urethrogram (RUG) is recommended prior to urethral catheter placement and cystography. (See "Overview of traumatic lower genitourinary tract injury".)

Peritonitis or abdominal sepsis as a complication of missed intraperitoneal rupture may be confused with traumatic rupture of other abdominal organs causing leakage of abdominal contents, leakage of bile, or bleeding (eg, small bowel, gallbladder, vascular injury). In such a setting, gross hematuria is highly associated with bladder injury and should prompt cystography; however, in the absence of hematuria, reduced urine output may prompt bladder evaluation, and/or routine CT scans may reveal perivesical fluid indicative of bladder injury. The presence of blood alone in the rectovesical pouch (eg, bleeding from abdominal organs, mesentery) is not likely to mimic bladder injury.

Spontaneous bladder rupture not related to direct trauma (blunt, penetrating, iatrogenic) is rare but has been reported following vomiting [28], resuscitation after cardiac arrest [29], after vaginal delivery [30], and in association with urinary tract pathologies. While the presenting symptoms are the same, the presence of other historical features (eg, radiation treatment) and a lack of significant associated trauma or other instrumentation will make the distinction.

INJURY CLASSIFICATION — Bladder injuries can be classified according to trauma injury scales typical of other organ injury scales, or anatomically, based on location and severity (table 1). Most urologists prefer to use anatomic classification as it is more informative for management. (See 'Approach to management' below.)

Bladder injury scale — The American Association for the Surgery of Trauma (AAST) grading system is given in the table (table 1) [31]. Although organ injury scales are commonly used for other organs, these are rarely reported for bladder injuries in the medical literature. The bladder injury scale is clinically challenging to use as it is not easy to accurately implement.

As an example, grading extraperitoneal bladder injuries that are often managed nonoperatively requires a distinction between injuries that are ≥2 cm and <2 cm, which is difficult to determine using radiographs alone.

Anatomic classification — To classify bladder injuries, most surgeons simply make a distinction between intraperitoneal versus extraperitoneal injuries and combined injuries, etiology, and whether the injury is complex.

Intraperitoneal versus extraperitoneal — Bladder injuries are broadly classified as intraperitoneal (ie, injury communicating with the peritoneum) or extraperitoneal (ie, injury confined to extraperitoneal space). Among traumatic injuries, extraperitoneal bladder injuries are more common (60 percent) and occur almost entirely in the setting of a pelvic fracture [14,23,32]. Blunt rupture as a result of a seatbelt injury is typically intraperitoneal. In one review, simultaneous extraperitoneal and intraperitoneal injuries occurred in 10 percent [32].

Simple versus complex extraperitoneal injury — Management of extraperitoneal bladder injuries is stratified based upon the presence of complex features, which include [14]:

●Open pelvic fracture with exposed bone within the bladder lumen.

●Concurrent rectal/vaginal injury to prevent subsequent fistula formation to the bladder.

●Bladder neck injury (image 1).

●Persistent hematuria as a consequence of the bladder injury with clots interfering with adequate bladder drainage.

APPROACH TO MANAGEMENT — Bladder injuries are managed according to anatomic classification (eg, intraperitoneal, extraperitoneal) and the complexity of the injury (algorithm 1) [14,23]. There are no randomized trials to guide the approach to treatment, which has evolved over time to include more conservative treatments [26].

For injuries that are managed with catheter drainage, cystography is recommended prior to catheter removal to ensure complete healing has occurred regardless of whether the injury was managed conservatively or required surgery.

Intraperitoneal bladder injury — Traumatic intraperitoneal bladder injuries warrant surgical repair since these injuries are typically large and will not heal spontaneously. Extravasation of urine into the peritoneum will cause peritonitis and ileus and, if prolonged, can lead to abdominal sepsis. Based on expert opinion [14], small iatrogenic intraperitoneal bladder injuries can be managed with drainage alone if there is no ileus or peritonitis. However, such patients should be closely observed, and the surgeon should have a low index of suspicion for proceeding with surgical repair. (See 'Surgical repair' below.)

Extraperitoneal bladder injury — Extraperitoneal bladder injuries are highly associated with pelvic fracture. In early series, all extraperitoneal bladder injuries were surgically repaired, but it became evident that avoiding laparotomy just to close extraperitoneal bladder injury was desirable [33]. Initial nonoperative management strategies were developed, and subsequently factors associated with poor healing were identified when bladder catheter drainage alone was used. These risk factors form the basis of the anatomic classification system used by urologists to stratify management of extraperitoneal bladder injury as complex or simple. As an example, we have noted delayed/poor healing of extraperitoneal bladder injuries managed with urethral catheter drainage alone in the setting of a complex open perineal wound. In such circumstances, early surgical repair may help avoid bladder fistulas to the perineal wound. Delayed repair of bladder neck injuries and bladder injury concomitant with pelvic, vaginal, or rectal injury are technically more difficult and associated with complications. (See 'Simple versus complex extraperitoneal injury' above.)

Complex — For most patients with complex extraperitoneal bladder injuries, we suggest early surgical repair because these may not heal with urethral drainage alone, and their presence can negatively impact management of patients with multiple injuries [14]. (See 'Surgical repair' below.)

Complex extraperitoneal bladder injuries includes [14]:

●Open pelvic fracture with exposed bone within the bladder lumen.

●Concurrent rectal/vaginal injury in order to prevent fistula formation to the bladder.

●Bladder neck injury (image 1).

●Persistent hematuria as a consequence of the bladder injury with clots interfering with adequate bladder drainage. Note that this circumstance should not be managed with a three-way catheter and continuous irrigation.

It is also reasonable to repair extraperitoneal bladder injury in patients who require surgery for another indication (eg, patients requiring open reduction/fixation of pelvic fracture and those requiring laparotomy for another reason).

Simple — Most simple (ie, not complex) extraperitoneal bladder injuries can be successfully managed nonoperatively (even in the presence of extensive retroperitoneal or scrotal extravasation). These injuries are best managed with urethral catheter drainage alone for two to three weeks; however, a longer period of catheterization may be necessary if there are significant concomitant injuries. Cystography should be performed prior to catheter removal to ensure that healing is complete. Persistent leakage beyond four weeks should prompt consideration for open bladder repair [14]. (See "Placement and management of urinary bladder catheters in adults".)

This practice is based on retrospective studies demonstrating that the majority of extraperitoneal bladder ruptures heal spontaneously [26,34-42] and is consistent with expert consensus guidelines [14,23,43]. In one of the early reviews, 39 patients with extraperitoneal bladder injuries were treated with catheter drainage alone and suffered no major complications [26]. Subsequent observational studies have verified the safety of nonoperative management for most simple extraperitoneal bladder injuries [34-37]. (See 'Simple versus complex extraperitoneal injury' above.)

In a larger review that included 80 patients with simple extraperitoneal traumatic bladder injuries, 56 were initially managed with catheter drainage alone and 24 were managed with early operative repair [37]. The injury severity score was not significantly different between the groups (37.5 versus 37.9), and noninjury-related complications and length of hospital length of stay were also similar. Nonoperative management was successful in 87.5 percent of the patients. Seven patients initially managed with catheter drainage ultimately required surgery (one prolonged urinary leak, six fistulas). One patient managed with early surgical repair required reoperation. All but one patient in the catheter drainage group ultimately had a negative cystogram by four months of follow-up. A weakness of this study was that an aggressive protocol of nonoperative management was pursued in select patients who should have undergone surgery in lieu of catheter drainage alone (ie, patients with extraperitoneal bladder injuries with large open perineal wounds) [44]. Four of the patients developed a fistula in the thigh, while two had perineal fistulas in the setting of an open perineal wound requiring diverting colostomy. Before the development of the fistula, four had undergone nonurologic operations without repairing the bladder [45]. (See 'Simple versus complex extraperitoneal injury' above.)

SURGICAL REPAIR — An infraumbilical abdominal incision is used unless there is an associated pelvic hematoma. Inspection of the bladder should be performed via the dome of the bladder to avoid extravesical dissection that can result in uncontrollable pelvic bleeding.

Bladder injuries (intraperitoneal, extraperitoneal) are repaired using a two-layer technique with urethral catheter drainage for two to three weeks [14]. There is no advantage to combined suprapubic/urethral catheter following repair of most bladder injuries [13,36,46]. Exceptions may include those who will require long-term catheterization (eg, head injury, spinal cord injury, complex bladder repair). As an example, if there is a tenuous repair, dual drainage provides a backup drainage source if one catheter obstructs. Cystography is recommended prior to catheter removal.

●Intraperitoneal injury – Blunt abdominal trauma can result in severe intraperitoneal bladder injuries when associated with a full bladder prior to injury. A large defect in the bladder is often seen, thus supporting primary repair for these injuries, since they are unlikely to heal with catheter drainage alone. Iatrogenic and penetrating injuries can be much smaller. Repair should be expedited once the patient is hemodynamically stable to avoid persistent leakage of urine into the peritoneum, which can increase morbidity. The majority of intraperitoneal bladder injuries are repaired in an open manner; however, laparoscopic closure has been described for small/simple repair [47,48]. During intraperitoneal repair, the remainder of the bladder, ureters, and bladder neck should also be examined for concomitant injury.

●Extraperitoneal injury – Bladder neck injuries are surgically repaired within the first seven days, once the patient is hemodynamically stable. Reapproximation of the bladder neck tissue may be all that is possible in this setting with the aim of reducing bladder neck urine extravasation. Delayed management of a bladder neck injury can result in significant morbidity, including stress incontinence, fistula, and stricture [49].

Pelvic fracture bone fragments that protrude into the bladder will interfere with bladder healing. Removal of the bone fragments and bladder repair is recommended. In the setting of a pelvic hematoma (ie, from associated pelvic fracture) and an extraperitoneal bladder injury that requires repair, the surgeon should avoid dissection into the pelvis to repair the extraperitoneal bladder injury as the dissection can result in uncontrollable pelvic bleeding and added morbidity. In such a situation, the bladder can be opened at the dome to repair the extraperitoneal bladder injury from the inside (ie, intravesical repair). Once the repair is completed, the dome of the bladder is closed as described for intraperitoneal injury.

FOLLOW-UP — Repeat cystography is recommended following nonoperative management and surgical management of extraperitoneal bladder injuries to assess healing [14,50]. Urinary drainage should remain in place until follow-up imaging. Most centers will obtain cystography two to three weeks after injury and/or repair. Repeat cystography is also recommended following surgical care for intraperitoneal bladder injuries two to three weeks after repair; however, avoidance of imaging has been proposed for "simple" repairs [14,23,50].

MORBIDITY AND MORTALITY — Mortality directly attributed to the bladder injury is uncommon as most deaths are a consequence of the associated pelvic fracture and hemodynamic instability [35,41]. In one database review, the mean Injury Severity Score (ISS) associated with bladder injuries was 23.8, and the overall mortality rate was 10.8 percent [35]. Unrecognized intraperitoneal bladder injuries can result in peritonitis, sepsis, ileus, and other associated complications. Unrecognized bladder neck injury can also result in significant morbidity, including stress incontinence, fistula, and stricture formation [49].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Genitourinary tract trauma in adults".)

SUMMARY AND RECOMMENDATIONS

●Injuries to the bladder are relatively uncommon. Injuries can occur due to blunt trauma, penetrating trauma, or by iatrogenic means. Extraperitoneal bladder injuries are more common and occur almost entirely in the setting of a pelvic fracture. Blunt rupture, typically as a result of a seatbelt injury, is typically intraperitoneal. (See 'Anatomy and mechanism of injury' above.)

●Clinical findings that suggest the presence of a bladder injury include gross hematuria, suprapubic tenderness, and/or difficulty voiding. A definitive diagnosis requires either directly identifying the injury at the time of laparotomy or imaging the bladder. Retrograde cystography (fluoroscopic or computed tomographic [CT] imaging) is the only imaging study to establish a diagnosis of bladder injury. Water-soluble contrast media is administered into the bladder via a urethral catheter; CT imaging with intravenous contrast (antegrade bladder filling) does not provide adequate imaging to diagnose a bladder injury. (See 'Diagnosis' above.)

●Bladder injuries are broadly classified anatomically as extraperitoneal (ie, injury confined to extraperitoneal space) or intraperitoneal (ie, injury communicating with the peritoneum) and, for extraperitoneal injures, as simple or complex.

Complex extraperitoneal bladder injuries include (see 'Anatomic classification' above):

•Bladder neck injury

•Open pelvic fracture with impinging bone into the bladder

•Concomitant rectal and/or vaginal injury

•Persistent hematuria impacting urinary drainage

●The management of bladder injuries is according to anatomic classification and complexity of the injury (algorithm 1). (See 'Approach to management' above.)

•For patients with simple (ie, not complex) extraperitoneal bladder injuries, initial conservative management with urethral catheter drainage alone is safe with a high rate of spontaneous bladder healing. (See 'Simple' above.)

•For complex extraperitoneal bladder injuries, we suggest early surgical repair rather than bladder catheter drainage alone (Grade 2C). These injuries are not likely to heal with urethral catheter drainage alone. Early repair is also reasonable for patients with pelvic fracture who require open reduction/fixation, or who have other indications for laparotomy. (See 'Complex' above.)

•Traumatic intraperitoneal bladder injuries should be repaired because they are typically large and will not heal with catheter drainage. We also repair most iatrogenic bladder injuries. Selected small intraperitoneal iatrogenic bladder injuries may be judiciously observed, with a low threshold for proceeding with surgical repair. (See 'Surgical repair' above.)

●Bladder injuries requiring surgery are repaired with a two-layer closure with urethral catheter drainage for two to three weeks. Dual catheter drainage (suprapubic tube, urethral catheter drainage) may be warranted in select circumstances. (See 'Surgical repair' above.)

●Cystography is recommended prior to catheter removal to ensure complete healing has occurred regardless of whether the injury was managed conservatively or required surgery. Avoidance of imaging for simple intraperitoneal repairs has also been advocated. (See 'Approach to management' above.)