- Email: [email protected]
Epidemiology of Blunt Lower Urinary Tract Trauma With and Without Pelvic Fracture
ARTICLE IN PRESS
Reconstructive Urology Epidemiology of Blunt Lower Urinary Tract Trauma With and Without Pelvic Fracture Niels V. Johnsen, Roger R. Dmochowski, Jason B. Young, and Oscar D. Guillamondegui OBJECTIVE METHODS
RESULTS
CONCLUSION
To assess the contemporary epidemiology of blunt trauma lower urinary tract injury (LUTI) and to evaluate outcomes in patients with and without associated pelvic fracture (PF). Patients presenting to our level I trauma center with PF and/or LUTI from blunt trauma from 2000 to 2014 were identified in our institutional trauma registry. Demographics, mechanism of injury, fracture configurations, hospital course, and outpatient disposition were analyzed. Of 5518 PF patients, 233 (4.2%) had LUTI. Thirty-four patients had non-PF LUTI. There were 3.2% of men and 3.3% of women with PF who had bladder injuries (P = .94). Urethral injury was more common in men (2.0% vs 0.05%; relative risk 43.1). Pubic arch fractures were present in 87% of patients with urethral injuries, although only 1.5% of patients with pubic arch fractures had urethral injury. Isolated acetabular fractures were never associated with urethral injury and associated with only 2.6% of bladder injuries. Extraperitoneal bladder ruptures were more common in the PF group as compared to the non-PF LUTI group (39.1% vs 14.7%, P < .01). Intensive care unit length of stay and hospital length of stay for PF vs non-PF patients were 7.1 ± 8.1 vs 2.8 ± 5.3 days (P < .01) and 13.5 ± 13.4 vs 7.7 ± 8.4 days (P = .01), respectively. These data suggest that the contemporary incidence of PF LUTI is lower than previously reported. The presence of PF in patients with LUTI is associated with more severe overall injuries, longer hospital stays, and increased rates of inpatient complications. UROLOGY ■■: ■■–■■, 2016. © 2016 Elsevier Inc.
L
ower urinary tract injury (LUTI) due to blunt trauma is a relatively rare occurrence, with the vast majority of these injuries (83%-95%) occurring in conjunction with pelvic fractures (PF). 1-3 Despite this association, a small percentage of patients still experience LUTI in the absence of PF and this patient population has not been thoroughly evaluated in the literature. Although earlier data suggest that bladder injuries occur in up to 10% of PF patients and urethral injuries occur in up to 6% of women and 10% of men with PF, the contemporary incidence and etiology of traumatic LUTI have not been fully reevaluated in a modern series.1-4 Historical studies have been from relatively small patient populations and none has thoroughly described the differences in presentation and outcomes between patients with and without associated PF. The aim of the present study was to review a 15-year single-institution experience with LUTI Financial Disclosure: The authors declare that they have no relevant financial interests. From the Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN; and the Division of Trauma and Surgical Critical Care, Vanderbilt University Medical Center, Nashville, TN Address correspondence to: Niels V. Johnsen, M.D., Department of Urologic Surgery, Vanderbilt University Medical Center, A-1302 Medical Center North, Nashville, TN 37232. E-mail: [email protected] Submitted: October 9, 2016, accepted (with revisions): November 7, 2016
© 2016 Elsevier Inc. All rights reserved.
secondary to blunt trauma to determine the contemporary epidemiology, as well as to compare initial inpatient outcomes between LUTI patients with and without associated PF.
METHODS All patients presenting to Vanderbilt University Medical Center for trauma between January 2000 and June 2014 were identified in our institutional trauma registry, a prospectively maintained database using the National Trauma Registry of the American College of Surgeons software. Inclusion criteria for entry into the registry have previously been described.5 All patients with International Classification of Disease version 9 diagnosis codes for traumatic fractures of the pelvis (808.0-808.9) as well as those with traumatic injuries to the bladder or urethra (867.0867.1) were extracted from this registry and evaluated. Only patients with injuries as a result of blunt trauma were included in the final analysis. To account for inaccuracies in registry coding, charts of patients with coded PF were randomly selected from each study year to evaluate for the presence or absence of missed LUTI. Similarly, the charts of all patients with coded LUTI in absence of PF were individually reviewed to identify miscoding for missed PF. http://dx.doi.org/10.1016/j.urology.2016.11.015 0090-4295
1
ARTICLE IN PRESS Retrospective chart review was performed for all patients with LUTI. Admission demographics including gender, arrival condition, overall injury severity, type of LUTI, and mechanism of injury were analyzed. Overall trauma severity was estimated using the Injury Severity Score (ISS) and calculated as previously described.6 For patients with PF, fracture configurations were determined based on International Classification of Disease version 9 coding and converted to the appropriate anatomical location. Hospital courses were evaluated specifically with regard to intensive care unit (ICU) and hospital length of stay (LOS), need for urologic operative intervention, and inpatient complications. Primary inpatient complications were categorized using the Clavien-Dindo system 7 and included incidences of pneumonia, urinary tract infection, bacteremia, acute kidney injury, need for hemodialysis, blood transfusion after initial resuscitation, secondary operative intervention for urologic injury-related complications, and death. Mortality was defined as death during the initial hospitalization. Statistical analysis was completed using Stata/IC v13.1. Categorical variables were analyzed using χ2 tests and continuous variables with the Student t test. All statistical tests were 2-sided with P < .05 considered statistically significant. Institutional review board exemption was provided for this study.
RESULTS Review of our trauma registry revealed 5718 patients with PF admitted between January 2000 and June of 2014. Of these, 200 were found to be from nonblunt injuries and were excluded from the final study population. Of the remaining 5518 patients, 242 were coded to have associated LUTI to the bladder, urethra, or both. Individual chart review revealed that 15 patients were incorrectly coded as having LUTI and were excluded. Similarly, 50 patients were identified as coded for LUTI in the absence of PF, of whom 10 did not in fact have LUTI, whereas 6 actually had PFassociated LUTI. On random review of PF patients not coded for LUTI, no LUTI patients were identified. In total, 34 patients were identified with non-PF blunt trauma LUTI and 233 patients with blunt PF LUTI. These 233 patients represented 4.2% (233 of 5518) of all blunt trauma PF patients. Of all patients with LUTI from blunt trauma, 87.3% (233 of 267) were associated with PF. An analysis of patients with PF LUTI (Table 1) revealed 164 men (70.4%) and 69 women (29.6%). Of the men, 94 had documented bladder injuries, 54 had urethral
Figure 1. Mechanism of injury in pelvic fracture-associated lower urinary tract injuries.
injuries, and 16 had both bladder and urethral injury. Of the women, 68 had bladder injuries and only 1 had a combined bladder and urethral injury. There was no difference in risk of PF-associated bladder injury between men and women (3.2% vs 3.3%, respectively; P = .94). However, men were significantly more likely to experience urethral injury associated with PF (2.0% vs 0.05%, respectively; P < .01, relative risk 43.1, 95% confidence interval 6.0309.9). Only 1 woman was identified with a urethral injury; however, this injury was in conjunction with a large bladder neck injury following a particularly devastating pelvic injury. Evaluation of the mechanisms of injury involved (Fig. 1) revealed that 74% of injuries were associated with motor vehicle or motorcycle accidents. However, whereas 81% of women were injured in motor vehicle accidents, only 46% of men were (P < .01). Similarly, men were much more likely to have been injured in motorcycle accidents (21% vs 7%, P < .01) or in workplace-related accidents (24% vs 4%, P < .01). There were no differences between genders in terms of condition at arrival, ISS scores, hospital courses, or discharge disposition. A review of the associated pelvic fracture patterns of those with LUTI revealed that 28.8% of patients had associated acetabular fractures, 29.2% had pubic arch fractures, 21.0% had ilium fractures, and 23.6% had multiple fractures with disruption of the pelvic circle (Fig. 2). Only 6 (2.6%) of the 233 patients with PF LUTI had isolated acetabular fractures in the absence of other pelvic fractures. Of these patients, 2 had extraperitoneal bladder ruptures, 1 had intraperitoneal rupture, and 2 had bladder contusions. There were no urethral injuries associated with
Table 1. Incidence of lower urinary tract injury associated with pelvic fracture by gender Gender Male (%) Female (%) Total (%)
2
Pelvic Fracture
Any Lower Urinary Tract Injury
Bladder
Urethra
3416 2102 5518
164 (4.8) 69 (3.3) 233 (4.2)
110 (3.2) 69 (3.3) 179 (3.2)
70 (2.0) 1 (0.05) 71 (1.3)
UROLOGY ■■ (■■), 2016
ARTICLE IN PRESS
Figure 2. Pelvic fracture configurations and associated lower urinary tract injuries.
isolated acetabular fractures. There were 87.0% of patients with urethral injuries who had pubic arch fractures, with 35.2% and 38.9% having fractures of the acetabulum and multiple fractures disrupting the pelvic circle, respectively. However, of all patients with documented pubic arch fractures, only 1.5% had associated urethral injuries. For patients experiencing bladder rupture, 31.5% had acetabular fractures, 25.9% had ilium fractures, 24.7% had multiple fractures disrupting the pelvic circle, and 19.1% had pubic arch fractures. Thirty-four patients (91.2% male) were identified with non-PF LUTI, representing just 12.7% of all LUTI patients during the study period. A comparison of demographics and outcomes between those with and without PF is displayed in Table 2. As expected with their associated injury patterns, patients with PF LUTI had higher mean ISS scores (37.9 vs 25.5, P < .01). The incidence of bladder, urethral, or combined injuries was not significantly different, at 69.5%, 23.1%, and 7.3% for the PF group, and 67.7%, 29.4%, and 2.9% for the non-PF group, respectively. PF patients, however, were significantly more likely to have extraperitoneal bladder ruptures (50.8% vs 20.8%, P < .01), whereas those without PF had a higher incidence of intraperitoneal ruptures (58.3% vs 24.0%, P < .01). Rates of urologic operative intervention (specifically, cystorrhaphy for bladder ruptures and urethral realignment or suprapubic catheter placement for urethral injuries) for PF LUTI and non-PF LUTI were not significantly different (50.6% vs 61.8%, P = .27). LOS was significantly longer for patients with concomitant PF, at 7.1 (±8.1) days vs 2.8 (±5.3) days in the ICU (P < .01) and 13.5 (±13.4) days vs 7.7 (±8.4) days in the hospital overall (P = .01). PF patients experienced increased rates of overall inpatient complications at a rate of 67.8% as compared to 20.6% in the non-PF cohort (P < .01). Clavien grade ≤ 2 complications occurred in 62.2% of PF patients, as compared to only 20.6% of nonPF patients (P < .01). Specifically, rates of pneumonia (24.5% vs 5.9%; P = .01), bacteremia (16.7% vs 0.0%; UROLOGY ■■ (■■), 2016
P < .01), and need for postresuscitative transfusion (60.1% vs 0.0%; P < .01) were all higher in PF patients. Clavien grade ≥ 3 complication rates were not significantly different. Non-PF patients were more likely to be discharged to home (76.5% vs 32.6%; P < .01). Incidence of inpatient mortality between those with and without PF trended toward but did not reach statistical significance (10.3% vs 0.0%; P = .05).
DISCUSSION The presence of PF following blunt trauma serves as a marker of significant injury from high-energy force. Although the morbidity from PF is well known and the association of LUTI with PF is similarly well established, the contemporary incidence has not been adequately analyzed and the differences in outcomes between LUTI patients with and without PF have not been previously addressed.2,3,6,8-12 The impact of traumatic LUTI on patientcentered outcomes should not be underestimated, as prior studies have shown that these injuries can result in significant morbidity not only in the acute setting but also in the long term.4,9,10,13-17 The present study is the first to evaluate the epidemiology of LUTI due to blunt trauma in a large contemporary cohort and to examine the role that concomitant PF has in influencing outcomes. This study finds that the overall incidence of LUTI from blunt pelvic trauma is low and actually quite lower than previously reported (only 4.2% of all PF).1-4 The vast majority of blunt LUTI remains associated with PF (87%) and these patients are shown to have both increased inpatient complications and increased LOS relative to those with LUTI in the absence of PF. Although there was a trend toward significance, we did not demonstrate a difference in mortality between groups, although we believe that this is likely a result of the rarity of LUTI overall and lack of sufficient statistical power to detect a difference. Although the bladder and urethra are relatively protected due to their anatomic location deep within the bony 3
ARTICLE IN PRESS Table 2. Demographics and hospital course comparing pelvic fracture and nonpelvic fracture lower urinary tract injury patients
Patients (%) Male Female Mean Injury Severity Score Bladder injury (%) Extraperitoneal Intraperitoneal Combined Contusion Urethral injury Bladder or urethral injury Operative intervention (%) Mean length of stay (±SD) ICU Hospital Complications (%) Overall Pneumonia UTI Bacteremia AKI Dialysis Postresuscitation transfusion Operative Disposition (%) Home Rehabilitation SNF Other Mortality
Pelvic Fracture
Nonpelvic Fracture
233 (87.3) 164 (70.4) 69 (29.6) 37.9 162 (69.5) 91 (50.8) 43 (24.0) 9 (5.0) 36 (20.1) 54 (23.1) 17 (7.3) 118 (50.6)
34 (12.7) 31 (91.2) 3 (8.8) 25.5 23 (67.7) 5 (20.8) 14 (58.3) 3 (12.5) 2 (8.3) 10 (29.4) 1 (2.9) 21 (61.8)
7.1 (8.1) 13.5 (13.4)
2.8 (5.3) 7.7 (8.4)
158 (67.8) 57 34 39 44 10 140 4 76 96 28 9 24
(32.6) (41.2) (12.0) (3.9) (10.3)
P Value
<.01 .84 <.01 <.01 .52 .48 .27 <.01 .01
7 (20.6) 2 2 0 2 0 0 0
<.01 .01 .28 <.01 .09 .37 <.01 1.00
26 (76.5) 7 (8.8) 1 (2.9) 0 0
<.01
.05
AKI, acute kidney injury; ICU, intensive care unit; SNF, skilled nursing facility; UTI, urinary tract infection.
pelvis, this close approximation does allow for injury during severe pelvic trauma. Extraperitoneal bladder ruptures, as seen in the present study, occur almost universally in the presence of PF and are usually the result of shearing forces or laceration by bony spicules.9,18 Intraperitoneal bladder ruptures, on the other hand, are most often due to blunt trauma to a distended bladder, resulting in elevated bladder pressures and perforation through the dome of the bladder.19 Female urethral injuries are exceedingly rare and in our series only occurred in 1 patient in conjunction with a severe bladder neck injury. The rarity of these injuries is believed to be secondary to the shorter urethral length and increased mobility due to its lack of attachment to the pubic bone.20 Male urethral injuries, however, are relatively more common and in the present study were 43 times more likely to occur in men with PF as compared to women. These injuries are believed to be the result of avulsion of the fixed bulbomembranous urethra from the urogenital diaphragm or possibly from direct laceration from bony fragments of the fractured pelvis.4,21 Using this mechanistic understanding of LUTI, previous investigators have attempted to predict injuries based on particular fracture configurations. Basta et al evaluated their experience with PF urethral injuries in 25 men and found that displaced fractures of the inferomedial pubic bone and symphysis pubis diastasis were independent 4
predictors of urethral injury, with each millimeter of inferomedial displacement or pubic diastasis resulting in an approximately 10% increased risk of urethral injury.20 Furthermore, these authors found that no urethral injuries occurred in patients with isolated acetabular fractures. Similarly, in the present study, we found that 87% of patients with urethral injuries had associated fractures of the pubic arch and there were no patients with isolated acetabular fractures who had urethral injuries. However, of all the patients with fractures of the pubis, only 1.5% had associated urethral injuries. In terms of predicting bladder ruptures with PF, Avey et al showed that symphysis pubis diastasis and obturator ring fractures with >1 cm displacement were independently associated with risk of rupture in their cohort of 37 patients. This study, however, did not differentiate between intraperitoneal and extraperitoneal bladder ruptures in terms of fracture patterns predicting injury.22 Our data do support these prior findings but highlight that further research is warranted on validating these clinical LUTI predictors in a larger cohort of patients. Prior to the present report, the largest single-institution study evaluating the incidence of PF-associated LUTI came from Los Angeles County Hospital.6 These authors, analyzing 8 years of trauma registry data, found that of their 1545 PF patients, 5.8% experienced LUTI, with male gender UROLOGY ■■ (■■), 2016
ARTICLE IN PRESS and pelvis Abbreviated Injury Score ≥4 as the only identified independent risk factors associated with LUTI. Unfortunately, bladder and urethral injuries were not evaluated independently and specific fracture configurations associated with LUTI were not assessed. Although 13.5% of patients with PF in their study died during initial hospitalization, the authors were unable to find an association between LUTI and mortality in their cohort. Similarly, in a recent study using the National Trauma Data Bank, Bjurlin et al found that the presence of LUTI was not an independent predictor of mortality in PF patients.23 However, by using Abbreviated Injury Score coding data, these authors were able to demonstrate that disruption of the pelvic circle resulted in the highest risk of associated injury to the urethra (odds ratio = 5.24) and bladder (odds ratio = 3.60). Although the National Trauma Data Bank has distinct advantages due its large power and diverse patient population, a significant limitation to the above study was that there was no standardization in the method of diagnosis of LUTI, nor were the investigators able to independently verify coding claims. The subset of patients who present with blunt trauma non-PF LUTI is often overlooked and has not been adequately described in the literature prior. In our study, only approximately 13% of all blunt LUTI patients had non– PF-associated injuries. When evaluating their particular injury patterns, we found that 74% of non-PF bladder ruptures were intraperitoneal or had an intraperitoneal component, as compared to only 32% of PF patients. This is not dissimilar from prior epidemiological studies of PF LUTI that extol a roughly “60-30-10” rule, with 60% of ruptures being extraperitoneal, 30% intraperitoneal, and 10% combined.10,18 Similarly, this higher incidence of intraperitoneal injuries is consistent with the previously described mechanics of injury. However, although intraperitoneal ruptures are almost universally treated operatively whereas extraperitoneal ruptures are often managed nonoperatively, we found no difference in rates of operative intervention between LUTI patients with and without PF (50.6% and 61.8%, respectively; P = .27).24 This is in part due to the higher number of associated urethral injuries in the PF cohort that were managed operatively with suprapubic catheterization and/or endoscopic realignment, as well as a higher proportion of patients undergoing operative repair for extraperitoneal injuries during nonurologic operative intervention for associated injuries at our institution, as previously described.14,15 Despite similarities in rates of surgical intervention, the absence of PF still lent itself to shorter ICU and hospital LOS, and decreased necessity for outpatient rehabilitation or skilled nursing care. This study is an epidemiological survey of our 15-year experience with PF and LUTI and does have a number of limitations. It is retrospective in nature and identification of study patients was made using registry and coding data. Although all LUTI patient charts were individually reviewed and a number of non-LUTI PF patient charts randomly selected and reviewed to identify discrepancies with coding, there exists the possibility that patients were UROLOGY ■■ (■■), 2016
inadvertently excluded. However, although we did identify a number of patients with PF LUTI who were coded as not having PF, our review of PF patient charts revealed no LUTI that were missed. Our incidence of PF LUTI is also lower than that published in many previous reports. Whether this is a result of a larger patient cohort more representative of the true incidence or in fact a reflection of improvements in contemporary motor vehicle safety devices such as airbags, seatbelts, and crush-resistant frames is unknown. Second, as is true with most studies evaluating the trauma population, we have minimal follow-up data, which prevents us from being able to assess the long-term morbidity of LUTI and to evaluate differences in functional and patient-reported outcomes between PF and nonPF groups. Lastly, our study cohort is regionally specific and also represents a population of patients who present to a tertiary care center. As such, the severity and frequency of injuries seen at our institution likely differs significantly than that seen in a community emergency department.
CONCLUSION This study represents the largest single-institution assessment of the epidemiology of blunt trauma LUTI and demonstrates that, in our experience, LUTI occurs in just 4.2% of all PF patients. Although 87% of LUTI occur in the presence of PF, the subset of patients who experience LUTI in the absence of PF tends to have shorter hospital stays, decreased risk of inpatient complications, and increased chance of discharge to home. More work is still needed to evaluate long-term functional and patient-reported outcomes in patients with non-PF LUTI and to compare these outcomes with those of the traditional PF LUTI population. References 1. Cass AS, Luxenberg M. Management of extraperitoneal ruptures of bladder caused by external trauma. Urology. 1989;33:179-183. 2. Corriere JN Jr, Sandler CM. Management of extraperitoneal bladder rupture. Urol Clin North Am. 1989;16:275-277. 3. Morey AF, Iverson AJ, Swan A, et al. Bladder rupture after blunt trauma: guidelines for diagnostic imaging. J Trauma. 2001;51:683686. 4. Koraitim MM. Pelvic fracture urethral injuries: the unresolved controversy. J Urol. 1999;161:1433-1441. 5. Committee on Trauma American College of Surgeons. Resources for Optimal Care of the Injured Patient, 2014. American College of Surgeons; 2014. 6. Demetriades D, Karaiskakis M, Toutouzas K, Alo K, Velmahos G, Chan L. Pelvic fractures: epidemiology and predictors of associated abdominal injuries and outcomes. J Am Coll Surg. 2002;195:1-10. 7. Dindo D, Demartines N, Clavien PA. Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205-213. 8. Black PC, Miller EA, Porter JR, Wessells H. Urethral and bladder neck injury associated with pelvic fracture in 25 female patients. J Urol. 2006;175:2140-2144, discussion 4. 9. Carroll PR, McAninch JW. Major bladder trauma: mechanisms of injury and a unified method of diagnosis and repair. J Urol. 1984;132:254-257. 10. Corriere JN Jr, Sandler CM. Management of the ruptured bladder: seven years of experience with 111 cases. J Trauma. 1986;26:830833.
5
ARTICLE IN PRESS 11. Hochberg E, Stone NN. Bladder rupture associated with pelvic fracture due to blunt trauma. Urology. 1993;41:531-533. 12. Spirnak JP. Pelvic fracture and injury to the lower urinary tract. Surg Clin North Am. 1988;68:1057-1069. 13. Mark SD, Keane TE, Vandemark RM, Webster GD. Impotence following pelvic fracture urethral injury: incidence, aetiology and management. Br J Urol. 1995;75:62-64. 14. Johnsen NV, Young JB, Reynolds WS, et al. Evaluating the role of operative repair of extraperitoneal bladder rupture following blunt pelvic trauma. J Urol. 2016;195:661-665. 15. Johnsen NV, Dmochowski RR, Mock S, Reynolds WS, Milam DF, Kaufman MR. Primary endoscopic realignment of urethral disruption injuries-a double-edged sword? J Urol. 2015;194:1022-1026. 16. Metze M, Tiemann AH, Josten C. Male sexual dysfunction after pelvic fracture. J Trauma. 2007;63:394-401. 17. Wright JL, Nathens AB, Rivara FP, MacKenzie EJ, Wessells H. Specific fracture configurations predict sexual and excretory dysfunction in men and women 1 year after pelvic fracture. J Urol. 2006;176(4 Pt 1):1540-1545, discussion 5.
6
18. Brandes S, Borrelli J Jr. Pelvic fracture and associated urologic injuries. World J Surg. 2001;25:1578-1587. 19. Gomez RG, Ceballos L, Coburn M, et al. Consensus statement on bladder injuries. BJU Int. 2004;94:27-32. 20. Basta AM, Blackmore CC, Wessells H. Predicting urethral injury from pelvic fracture patterns in male patients with blunt trauma. J Urol. 2007;177:571-575. 21. Andrich DE, Day AC, Mundy AR. Proposed mechanisms of lower urinary tract injury in fractures of the pelvic ring. BJU Int. 2007;100:567-573. 22. Avey G, Blackmore CC, Wessells H, Wright JL, Talner LB. Radiographic and clinical predictors of bladder rupture in blunt trauma patients with pelvic fracture. Acad Radiol. 2006;13:573579. 23. Bjurlin MA, Fantus RJ, Mellett MM, Goble SM. Genitourinary injuries in pelvic fracture morbidity and mortality using the National Trauma Data Bank. J Trauma. 2009;67:1033-1039. 24. Morey AF, Brandes S, Dugi DD 3rd, et al. Urotrauma: AUA guideline. J Urol. 2014;192:327-335.
UROLOGY ■■ (■■), 2016
Reconstructive Urology Epidemiology of Blunt Lower Urinary Tract Trauma With and Without Pelvic Fracture Niels V. Johnsen, Roger R. Dmochowski, Jason B. Young, and Oscar D. Guillamondegui OBJECTIVE METHODS
RESULTS
CONCLUSION
To assess the contemporary epidemiology of blunt trauma lower urinary tract injury (LUTI) and to evaluate outcomes in patients with and without associated pelvic fracture (PF). Patients presenting to our level I trauma center with PF and/or LUTI from blunt trauma from 2000 to 2014 were identified in our institutional trauma registry. Demographics, mechanism of injury, fracture configurations, hospital course, and outpatient disposition were analyzed. Of 5518 PF patients, 233 (4.2%) had LUTI. Thirty-four patients had non-PF LUTI. There were 3.2% of men and 3.3% of women with PF who had bladder injuries (P = .94). Urethral injury was more common in men (2.0% vs 0.05%; relative risk 43.1). Pubic arch fractures were present in 87% of patients with urethral injuries, although only 1.5% of patients with pubic arch fractures had urethral injury. Isolated acetabular fractures were never associated with urethral injury and associated with only 2.6% of bladder injuries. Extraperitoneal bladder ruptures were more common in the PF group as compared to the non-PF LUTI group (39.1% vs 14.7%, P < .01). Intensive care unit length of stay and hospital length of stay for PF vs non-PF patients were 7.1 ± 8.1 vs 2.8 ± 5.3 days (P < .01) and 13.5 ± 13.4 vs 7.7 ± 8.4 days (P = .01), respectively. These data suggest that the contemporary incidence of PF LUTI is lower than previously reported. The presence of PF in patients with LUTI is associated with more severe overall injuries, longer hospital stays, and increased rates of inpatient complications. UROLOGY ■■: ■■–■■, 2016. © 2016 Elsevier Inc.
L
ower urinary tract injury (LUTI) due to blunt trauma is a relatively rare occurrence, with the vast majority of these injuries (83%-95%) occurring in conjunction with pelvic fractures (PF). 1-3 Despite this association, a small percentage of patients still experience LUTI in the absence of PF and this patient population has not been thoroughly evaluated in the literature. Although earlier data suggest that bladder injuries occur in up to 10% of PF patients and urethral injuries occur in up to 6% of women and 10% of men with PF, the contemporary incidence and etiology of traumatic LUTI have not been fully reevaluated in a modern series.1-4 Historical studies have been from relatively small patient populations and none has thoroughly described the differences in presentation and outcomes between patients with and without associated PF. The aim of the present study was to review a 15-year single-institution experience with LUTI Financial Disclosure: The authors declare that they have no relevant financial interests. From the Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN; and the Division of Trauma and Surgical Critical Care, Vanderbilt University Medical Center, Nashville, TN Address correspondence to: Niels V. Johnsen, M.D., Department of Urologic Surgery, Vanderbilt University Medical Center, A-1302 Medical Center North, Nashville, TN 37232. E-mail: [email protected] Submitted: October 9, 2016, accepted (with revisions): November 7, 2016
© 2016 Elsevier Inc. All rights reserved.
secondary to blunt trauma to determine the contemporary epidemiology, as well as to compare initial inpatient outcomes between LUTI patients with and without associated PF.
METHODS All patients presenting to Vanderbilt University Medical Center for trauma between January 2000 and June 2014 were identified in our institutional trauma registry, a prospectively maintained database using the National Trauma Registry of the American College of Surgeons software. Inclusion criteria for entry into the registry have previously been described.5 All patients with International Classification of Disease version 9 diagnosis codes for traumatic fractures of the pelvis (808.0-808.9) as well as those with traumatic injuries to the bladder or urethra (867.0867.1) were extracted from this registry and evaluated. Only patients with injuries as a result of blunt trauma were included in the final analysis. To account for inaccuracies in registry coding, charts of patients with coded PF were randomly selected from each study year to evaluate for the presence or absence of missed LUTI. Similarly, the charts of all patients with coded LUTI in absence of PF were individually reviewed to identify miscoding for missed PF. http://dx.doi.org/10.1016/j.urology.2016.11.015 0090-4295
1
ARTICLE IN PRESS Retrospective chart review was performed for all patients with LUTI. Admission demographics including gender, arrival condition, overall injury severity, type of LUTI, and mechanism of injury were analyzed. Overall trauma severity was estimated using the Injury Severity Score (ISS) and calculated as previously described.6 For patients with PF, fracture configurations were determined based on International Classification of Disease version 9 coding and converted to the appropriate anatomical location. Hospital courses were evaluated specifically with regard to intensive care unit (ICU) and hospital length of stay (LOS), need for urologic operative intervention, and inpatient complications. Primary inpatient complications were categorized using the Clavien-Dindo system 7 and included incidences of pneumonia, urinary tract infection, bacteremia, acute kidney injury, need for hemodialysis, blood transfusion after initial resuscitation, secondary operative intervention for urologic injury-related complications, and death. Mortality was defined as death during the initial hospitalization. Statistical analysis was completed using Stata/IC v13.1. Categorical variables were analyzed using χ2 tests and continuous variables with the Student t test. All statistical tests were 2-sided with P < .05 considered statistically significant. Institutional review board exemption was provided for this study.
RESULTS Review of our trauma registry revealed 5718 patients with PF admitted between January 2000 and June of 2014. Of these, 200 were found to be from nonblunt injuries and were excluded from the final study population. Of the remaining 5518 patients, 242 were coded to have associated LUTI to the bladder, urethra, or both. Individual chart review revealed that 15 patients were incorrectly coded as having LUTI and were excluded. Similarly, 50 patients were identified as coded for LUTI in the absence of PF, of whom 10 did not in fact have LUTI, whereas 6 actually had PFassociated LUTI. On random review of PF patients not coded for LUTI, no LUTI patients were identified. In total, 34 patients were identified with non-PF blunt trauma LUTI and 233 patients with blunt PF LUTI. These 233 patients represented 4.2% (233 of 5518) of all blunt trauma PF patients. Of all patients with LUTI from blunt trauma, 87.3% (233 of 267) were associated with PF. An analysis of patients with PF LUTI (Table 1) revealed 164 men (70.4%) and 69 women (29.6%). Of the men, 94 had documented bladder injuries, 54 had urethral
Figure 1. Mechanism of injury in pelvic fracture-associated lower urinary tract injuries.
injuries, and 16 had both bladder and urethral injury. Of the women, 68 had bladder injuries and only 1 had a combined bladder and urethral injury. There was no difference in risk of PF-associated bladder injury between men and women (3.2% vs 3.3%, respectively; P = .94). However, men were significantly more likely to experience urethral injury associated with PF (2.0% vs 0.05%, respectively; P < .01, relative risk 43.1, 95% confidence interval 6.0309.9). Only 1 woman was identified with a urethral injury; however, this injury was in conjunction with a large bladder neck injury following a particularly devastating pelvic injury. Evaluation of the mechanisms of injury involved (Fig. 1) revealed that 74% of injuries were associated with motor vehicle or motorcycle accidents. However, whereas 81% of women were injured in motor vehicle accidents, only 46% of men were (P < .01). Similarly, men were much more likely to have been injured in motorcycle accidents (21% vs 7%, P < .01) or in workplace-related accidents (24% vs 4%, P < .01). There were no differences between genders in terms of condition at arrival, ISS scores, hospital courses, or discharge disposition. A review of the associated pelvic fracture patterns of those with LUTI revealed that 28.8% of patients had associated acetabular fractures, 29.2% had pubic arch fractures, 21.0% had ilium fractures, and 23.6% had multiple fractures with disruption of the pelvic circle (Fig. 2). Only 6 (2.6%) of the 233 patients with PF LUTI had isolated acetabular fractures in the absence of other pelvic fractures. Of these patients, 2 had extraperitoneal bladder ruptures, 1 had intraperitoneal rupture, and 2 had bladder contusions. There were no urethral injuries associated with
Table 1. Incidence of lower urinary tract injury associated with pelvic fracture by gender Gender Male (%) Female (%) Total (%)
2
Pelvic Fracture
Any Lower Urinary Tract Injury
Bladder
Urethra
3416 2102 5518
164 (4.8) 69 (3.3) 233 (4.2)
110 (3.2) 69 (3.3) 179 (3.2)
70 (2.0) 1 (0.05) 71 (1.3)
UROLOGY ■■ (■■), 2016
ARTICLE IN PRESS
Figure 2. Pelvic fracture configurations and associated lower urinary tract injuries.
isolated acetabular fractures. There were 87.0% of patients with urethral injuries who had pubic arch fractures, with 35.2% and 38.9% having fractures of the acetabulum and multiple fractures disrupting the pelvic circle, respectively. However, of all patients with documented pubic arch fractures, only 1.5% had associated urethral injuries. For patients experiencing bladder rupture, 31.5% had acetabular fractures, 25.9% had ilium fractures, 24.7% had multiple fractures disrupting the pelvic circle, and 19.1% had pubic arch fractures. Thirty-four patients (91.2% male) were identified with non-PF LUTI, representing just 12.7% of all LUTI patients during the study period. A comparison of demographics and outcomes between those with and without PF is displayed in Table 2. As expected with their associated injury patterns, patients with PF LUTI had higher mean ISS scores (37.9 vs 25.5, P < .01). The incidence of bladder, urethral, or combined injuries was not significantly different, at 69.5%, 23.1%, and 7.3% for the PF group, and 67.7%, 29.4%, and 2.9% for the non-PF group, respectively. PF patients, however, were significantly more likely to have extraperitoneal bladder ruptures (50.8% vs 20.8%, P < .01), whereas those without PF had a higher incidence of intraperitoneal ruptures (58.3% vs 24.0%, P < .01). Rates of urologic operative intervention (specifically, cystorrhaphy for bladder ruptures and urethral realignment or suprapubic catheter placement for urethral injuries) for PF LUTI and non-PF LUTI were not significantly different (50.6% vs 61.8%, P = .27). LOS was significantly longer for patients with concomitant PF, at 7.1 (±8.1) days vs 2.8 (±5.3) days in the ICU (P < .01) and 13.5 (±13.4) days vs 7.7 (±8.4) days in the hospital overall (P = .01). PF patients experienced increased rates of overall inpatient complications at a rate of 67.8% as compared to 20.6% in the non-PF cohort (P < .01). Clavien grade ≤ 2 complications occurred in 62.2% of PF patients, as compared to only 20.6% of nonPF patients (P < .01). Specifically, rates of pneumonia (24.5% vs 5.9%; P = .01), bacteremia (16.7% vs 0.0%; UROLOGY ■■ (■■), 2016
P < .01), and need for postresuscitative transfusion (60.1% vs 0.0%; P < .01) were all higher in PF patients. Clavien grade ≥ 3 complication rates were not significantly different. Non-PF patients were more likely to be discharged to home (76.5% vs 32.6%; P < .01). Incidence of inpatient mortality between those with and without PF trended toward but did not reach statistical significance (10.3% vs 0.0%; P = .05).
DISCUSSION The presence of PF following blunt trauma serves as a marker of significant injury from high-energy force. Although the morbidity from PF is well known and the association of LUTI with PF is similarly well established, the contemporary incidence has not been adequately analyzed and the differences in outcomes between LUTI patients with and without PF have not been previously addressed.2,3,6,8-12 The impact of traumatic LUTI on patientcentered outcomes should not be underestimated, as prior studies have shown that these injuries can result in significant morbidity not only in the acute setting but also in the long term.4,9,10,13-17 The present study is the first to evaluate the epidemiology of LUTI due to blunt trauma in a large contemporary cohort and to examine the role that concomitant PF has in influencing outcomes. This study finds that the overall incidence of LUTI from blunt pelvic trauma is low and actually quite lower than previously reported (only 4.2% of all PF).1-4 The vast majority of blunt LUTI remains associated with PF (87%) and these patients are shown to have both increased inpatient complications and increased LOS relative to those with LUTI in the absence of PF. Although there was a trend toward significance, we did not demonstrate a difference in mortality between groups, although we believe that this is likely a result of the rarity of LUTI overall and lack of sufficient statistical power to detect a difference. Although the bladder and urethra are relatively protected due to their anatomic location deep within the bony 3
ARTICLE IN PRESS Table 2. Demographics and hospital course comparing pelvic fracture and nonpelvic fracture lower urinary tract injury patients
Patients (%) Male Female Mean Injury Severity Score Bladder injury (%) Extraperitoneal Intraperitoneal Combined Contusion Urethral injury Bladder or urethral injury Operative intervention (%) Mean length of stay (±SD) ICU Hospital Complications (%) Overall Pneumonia UTI Bacteremia AKI Dialysis Postresuscitation transfusion Operative Disposition (%) Home Rehabilitation SNF Other Mortality
Pelvic Fracture
Nonpelvic Fracture
233 (87.3) 164 (70.4) 69 (29.6) 37.9 162 (69.5) 91 (50.8) 43 (24.0) 9 (5.0) 36 (20.1) 54 (23.1) 17 (7.3) 118 (50.6)
34 (12.7) 31 (91.2) 3 (8.8) 25.5 23 (67.7) 5 (20.8) 14 (58.3) 3 (12.5) 2 (8.3) 10 (29.4) 1 (2.9) 21 (61.8)
7.1 (8.1) 13.5 (13.4)
2.8 (5.3) 7.7 (8.4)
158 (67.8) 57 34 39 44 10 140 4 76 96 28 9 24
(32.6) (41.2) (12.0) (3.9) (10.3)
P Value
<.01 .84 <.01 <.01 .52 .48 .27 <.01 .01
7 (20.6) 2 2 0 2 0 0 0
<.01 .01 .28 <.01 .09 .37 <.01 1.00
26 (76.5) 7 (8.8) 1 (2.9) 0 0
<.01
.05
AKI, acute kidney injury; ICU, intensive care unit; SNF, skilled nursing facility; UTI, urinary tract infection.
pelvis, this close approximation does allow for injury during severe pelvic trauma. Extraperitoneal bladder ruptures, as seen in the present study, occur almost universally in the presence of PF and are usually the result of shearing forces or laceration by bony spicules.9,18 Intraperitoneal bladder ruptures, on the other hand, are most often due to blunt trauma to a distended bladder, resulting in elevated bladder pressures and perforation through the dome of the bladder.19 Female urethral injuries are exceedingly rare and in our series only occurred in 1 patient in conjunction with a severe bladder neck injury. The rarity of these injuries is believed to be secondary to the shorter urethral length and increased mobility due to its lack of attachment to the pubic bone.20 Male urethral injuries, however, are relatively more common and in the present study were 43 times more likely to occur in men with PF as compared to women. These injuries are believed to be the result of avulsion of the fixed bulbomembranous urethra from the urogenital diaphragm or possibly from direct laceration from bony fragments of the fractured pelvis.4,21 Using this mechanistic understanding of LUTI, previous investigators have attempted to predict injuries based on particular fracture configurations. Basta et al evaluated their experience with PF urethral injuries in 25 men and found that displaced fractures of the inferomedial pubic bone and symphysis pubis diastasis were independent 4
predictors of urethral injury, with each millimeter of inferomedial displacement or pubic diastasis resulting in an approximately 10% increased risk of urethral injury.20 Furthermore, these authors found that no urethral injuries occurred in patients with isolated acetabular fractures. Similarly, in the present study, we found that 87% of patients with urethral injuries had associated fractures of the pubic arch and there were no patients with isolated acetabular fractures who had urethral injuries. However, of all the patients with fractures of the pubis, only 1.5% had associated urethral injuries. In terms of predicting bladder ruptures with PF, Avey et al showed that symphysis pubis diastasis and obturator ring fractures with >1 cm displacement were independently associated with risk of rupture in their cohort of 37 patients. This study, however, did not differentiate between intraperitoneal and extraperitoneal bladder ruptures in terms of fracture patterns predicting injury.22 Our data do support these prior findings but highlight that further research is warranted on validating these clinical LUTI predictors in a larger cohort of patients. Prior to the present report, the largest single-institution study evaluating the incidence of PF-associated LUTI came from Los Angeles County Hospital.6 These authors, analyzing 8 years of trauma registry data, found that of their 1545 PF patients, 5.8% experienced LUTI, with male gender UROLOGY ■■ (■■), 2016
ARTICLE IN PRESS and pelvis Abbreviated Injury Score ≥4 as the only identified independent risk factors associated with LUTI. Unfortunately, bladder and urethral injuries were not evaluated independently and specific fracture configurations associated with LUTI were not assessed. Although 13.5% of patients with PF in their study died during initial hospitalization, the authors were unable to find an association between LUTI and mortality in their cohort. Similarly, in a recent study using the National Trauma Data Bank, Bjurlin et al found that the presence of LUTI was not an independent predictor of mortality in PF patients.23 However, by using Abbreviated Injury Score coding data, these authors were able to demonstrate that disruption of the pelvic circle resulted in the highest risk of associated injury to the urethra (odds ratio = 5.24) and bladder (odds ratio = 3.60). Although the National Trauma Data Bank has distinct advantages due its large power and diverse patient population, a significant limitation to the above study was that there was no standardization in the method of diagnosis of LUTI, nor were the investigators able to independently verify coding claims. The subset of patients who present with blunt trauma non-PF LUTI is often overlooked and has not been adequately described in the literature prior. In our study, only approximately 13% of all blunt LUTI patients had non– PF-associated injuries. When evaluating their particular injury patterns, we found that 74% of non-PF bladder ruptures were intraperitoneal or had an intraperitoneal component, as compared to only 32% of PF patients. This is not dissimilar from prior epidemiological studies of PF LUTI that extol a roughly “60-30-10” rule, with 60% of ruptures being extraperitoneal, 30% intraperitoneal, and 10% combined.10,18 Similarly, this higher incidence of intraperitoneal injuries is consistent with the previously described mechanics of injury. However, although intraperitoneal ruptures are almost universally treated operatively whereas extraperitoneal ruptures are often managed nonoperatively, we found no difference in rates of operative intervention between LUTI patients with and without PF (50.6% and 61.8%, respectively; P = .27).24 This is in part due to the higher number of associated urethral injuries in the PF cohort that were managed operatively with suprapubic catheterization and/or endoscopic realignment, as well as a higher proportion of patients undergoing operative repair for extraperitoneal injuries during nonurologic operative intervention for associated injuries at our institution, as previously described.14,15 Despite similarities in rates of surgical intervention, the absence of PF still lent itself to shorter ICU and hospital LOS, and decreased necessity for outpatient rehabilitation or skilled nursing care. This study is an epidemiological survey of our 15-year experience with PF and LUTI and does have a number of limitations. It is retrospective in nature and identification of study patients was made using registry and coding data. Although all LUTI patient charts were individually reviewed and a number of non-LUTI PF patient charts randomly selected and reviewed to identify discrepancies with coding, there exists the possibility that patients were UROLOGY ■■ (■■), 2016
inadvertently excluded. However, although we did identify a number of patients with PF LUTI who were coded as not having PF, our review of PF patient charts revealed no LUTI that were missed. Our incidence of PF LUTI is also lower than that published in many previous reports. Whether this is a result of a larger patient cohort more representative of the true incidence or in fact a reflection of improvements in contemporary motor vehicle safety devices such as airbags, seatbelts, and crush-resistant frames is unknown. Second, as is true with most studies evaluating the trauma population, we have minimal follow-up data, which prevents us from being able to assess the long-term morbidity of LUTI and to evaluate differences in functional and patient-reported outcomes between PF and nonPF groups. Lastly, our study cohort is regionally specific and also represents a population of patients who present to a tertiary care center. As such, the severity and frequency of injuries seen at our institution likely differs significantly than that seen in a community emergency department.
CONCLUSION This study represents the largest single-institution assessment of the epidemiology of blunt trauma LUTI and demonstrates that, in our experience, LUTI occurs in just 4.2% of all PF patients. Although 87% of LUTI occur in the presence of PF, the subset of patients who experience LUTI in the absence of PF tends to have shorter hospital stays, decreased risk of inpatient complications, and increased chance of discharge to home. More work is still needed to evaluate long-term functional and patient-reported outcomes in patients with non-PF LUTI and to compare these outcomes with those of the traditional PF LUTI population. References 1. Cass AS, Luxenberg M. Management of extraperitoneal ruptures of bladder caused by external trauma. Urology. 1989;33:179-183. 2. Corriere JN Jr, Sandler CM. Management of extraperitoneal bladder rupture. Urol Clin North Am. 1989;16:275-277. 3. Morey AF, Iverson AJ, Swan A, et al. Bladder rupture after blunt trauma: guidelines for diagnostic imaging. J Trauma. 2001;51:683686. 4. Koraitim MM. Pelvic fracture urethral injuries: the unresolved controversy. J Urol. 1999;161:1433-1441. 5. Committee on Trauma American College of Surgeons. Resources for Optimal Care of the Injured Patient, 2014. American College of Surgeons; 2014. 6. Demetriades D, Karaiskakis M, Toutouzas K, Alo K, Velmahos G, Chan L. Pelvic fractures: epidemiology and predictors of associated abdominal injuries and outcomes. J Am Coll Surg. 2002;195:1-10. 7. Dindo D, Demartines N, Clavien PA. Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205-213. 8. Black PC, Miller EA, Porter JR, Wessells H. Urethral and bladder neck injury associated with pelvic fracture in 25 female patients. J Urol. 2006;175:2140-2144, discussion 4. 9. Carroll PR, McAninch JW. Major bladder trauma: mechanisms of injury and a unified method of diagnosis and repair. J Urol. 1984;132:254-257. 10. Corriere JN Jr, Sandler CM. Management of the ruptured bladder: seven years of experience with 111 cases. J Trauma. 1986;26:830833.
5
ARTICLE IN PRESS 11. Hochberg E, Stone NN. Bladder rupture associated with pelvic fracture due to blunt trauma. Urology. 1993;41:531-533. 12. Spirnak JP. Pelvic fracture and injury to the lower urinary tract. Surg Clin North Am. 1988;68:1057-1069. 13. Mark SD, Keane TE, Vandemark RM, Webster GD. Impotence following pelvic fracture urethral injury: incidence, aetiology and management. Br J Urol. 1995;75:62-64. 14. Johnsen NV, Young JB, Reynolds WS, et al. Evaluating the role of operative repair of extraperitoneal bladder rupture following blunt pelvic trauma. J Urol. 2016;195:661-665. 15. Johnsen NV, Dmochowski RR, Mock S, Reynolds WS, Milam DF, Kaufman MR. Primary endoscopic realignment of urethral disruption injuries-a double-edged sword? J Urol. 2015;194:1022-1026. 16. Metze M, Tiemann AH, Josten C. Male sexual dysfunction after pelvic fracture. J Trauma. 2007;63:394-401. 17. Wright JL, Nathens AB, Rivara FP, MacKenzie EJ, Wessells H. Specific fracture configurations predict sexual and excretory dysfunction in men and women 1 year after pelvic fracture. J Urol. 2006;176(4 Pt 1):1540-1545, discussion 5.
6
18. Brandes S, Borrelli J Jr. Pelvic fracture and associated urologic injuries. World J Surg. 2001;25:1578-1587. 19. Gomez RG, Ceballos L, Coburn M, et al. Consensus statement on bladder injuries. BJU Int. 2004;94:27-32. 20. Basta AM, Blackmore CC, Wessells H. Predicting urethral injury from pelvic fracture patterns in male patients with blunt trauma. J Urol. 2007;177:571-575. 21. Andrich DE, Day AC, Mundy AR. Proposed mechanisms of lower urinary tract injury in fractures of the pelvic ring. BJU Int. 2007;100:567-573. 22. Avey G, Blackmore CC, Wessells H, Wright JL, Talner LB. Radiographic and clinical predictors of bladder rupture in blunt trauma patients with pelvic fracture. Acad Radiol. 2006;13:573579. 23. Bjurlin MA, Fantus RJ, Mellett MM, Goble SM. Genitourinary injuries in pelvic fracture morbidity and mortality using the National Trauma Data Bank. J Trauma. 2009;67:1033-1039. 24. Morey AF, Brandes S, Dugi DD 3rd, et al. Urotrauma: AUA guideline. J Urol. 2014;192:327-335.
UROLOGY ■■ (■■), 2016