Hidden dangers of pelvic fracture: A meta-analysis on urinary tract injury incidence and risk factors

Abstract

BACKGROUND

Pelvic fractures are often associated with significant morbidity, including injuries to the urinary tract. Understanding the incidence and risk factors for urinary tract injury in these patients is crucial for prompt diagnosis and management. This meta-analysis aims to synthesize existing evidence to determine the overall incidence and identify specific risk factors associated with urinary tract injuries in patients with pelvic fractures.

AIM

To determine the incidence and risk factors for urinary tract injuries in patients with pelvic fractures.

METHODS

A systematic search of PubMed, EMBASE, Scopus, and the Cochrane Library was conducted without date restrictions. Studies examining the incidence and risk factors of urinary tract injuries in patients with pelvic fractures were included. Data extracted included demographics, injury mechanism, pelvic fracture type, urinary tract injury incidence, mortality, and discharge disposition. Review Manager 5.4 was used for data analysis.

RESULTS

Ten studies comprising 22700 patients were included. The pooled incidence of urinary tract injury associated with pelvic fracture was 6.88% (95%CI: 6.20%-7.55%). Vehicle, motorcycle, and pedestrian accidents were identified as risk factors for urinary tract injury, with relative risks (RR) of 1.08 (95%CI: 1.06-1.11), 1.89 (95%CI: 1.78-2.00), and 1.53 (95%CI: 1.20-1.95), respectively. Pubic fracture and pelvic ring disruption were significantly associated with urinary tract injury [odds ratio (OR) 1.94, 95%CI: 1.09-3.44 and OR 5.53, 95%CI: 4.67-6.54, respectively)]. Patients without urinary tract injury were more likely to be discharged home (RR 0.79, 95%CI: 0.67-0.92). Mortality was higher in patients with urinary tract injury (OR 1.92, 95%CI: 1.77-2.09).

CONCLUSION

Urinary tract injury occurs in nearly 7% of patients with pelvic fractures. Motorcycle accidents, pubic fractures, and pelvic ring disruptions are significant risk factors. Urinary tract injury following pelvic fracture is associated with increased mortality.

Key Words: Urinary tract; Urologic; Pelvic fracture; Pelvic injury; Incidence; Meta-analysis

Core Tip: This meta-analysis investigates the incidence of urinary tract injuries associated with pelvic fractures, revealing a prevalence of 6.88%. It identifies key risk factors, including vehicle and motorcycle accidents, and highlights the significant associations between specific fracture types, such as pubic fractures and pelvic ring disruptions, and urinary injuries. The findings underscore the importance of early detection and intervention to reduce morbidity and mortality in affected patients.

INTRODUCTION

Pelvic fractures are a significant consequence of high-energy trauma and are often observed in patients who have suffered serious accidents. These accidents can involve car crashes, motorcycle accidents, falls from great heights, and other similar incidents[1]. The pelvic region is an essential part of the body, housing many vital organs and structures, including the bladder, colon, rectum, and reproductive organs, making pelvic fractures potentially life-threatening[1]. In addition to life-threatening bleeding, pelvic fractures are associated with significant morbidity. The morbidities associated with pelvic fractures can include damage to the bladder and urethra, leading to incontinence, and damage to the rectum, leading to fecal incontinence[2-4]. Pelvic fractures can cause nerve damage, leading to sexual dysfunctionand infertility[3]. In some cases, pelvic fractures can also lead to complications, such as sepsis, pelvic abscesses, and peritonitis. These complications can be life threatening and require immediate medical intervention.

Owing to the potential severity of pelvic fractures, early diagnosis and treatment are essential[5]. In many cases, pelvic fractures require surgery to repair the damage and restore function of the affected organs and structures. It is also essential to involve a multidisciplinary team of surgeons, including urologists and colorectal surgeons, in the treatment of pelvic fractures to ensure that all injuries are appropriately managed[6]. The diagnosis of pelvic fractures can be challenging, and many patients may not display symptoms immediately after injury. In some cases, patients with pelvic fractures may not realize that they have suffered an injury until complications arise. Therefore, it is essential to maintain a high index of suspicion and be vigilant in monitoring patients who have suffered from high-energy trauma for signs of pelvic fractures.

The treatment of pelvic fractures can be complicated and management often requires a significant amount of resources. The direct cost of pelvic fractures can be significant, with estimates ranging from $30000 to $50000 per patient[7]. Additionally, the indirect costs of pelvic fractures, including lost wages, can be significant, particularly for young patients[7,8].

Given the complexity and potential severity of pelvic fractures, it is essential to identify the risk factors and trends in associated injuries to improve early detection and management. Several studies have identified predictors of mortality in patients with pelvic fractures, including age, Injury Severity Score, and blood transfusion[1,9]. However, research on the association between pelvic fractures and genitourinary injuries[10].

This meta-analysis aimed to determine the actual incidence of genitourinary injuries associated with pelvic fractures and to identify risk factors or associations that may help surgeons detect these injuries early. By identifying these factors, surgeons can improve the management of pelvic fractures and reduce morbidity and mortality associated with these injuries.

MATERIALS AND METHODS

Eligibility criteria

In this study, a protocol was established to guide the justification of the study, inclusion criteria, literature search, data extraction, and outcome assessment. The study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to ensure transparency and completeness in reporting[11]. The search strategy followed the PICOS framework, where P referred to patients with pelvic fractures and urinary tract injury, I referred to studies that included patients with pelvic fractures and urinary tract injury, C referred to patients with pelvic fractures without urinary tract injury, O referred to the outcomes of interest, including the incidence of pelvic-fracture-associated urinary tract injury and risk factors, and S referred to studies that analyzed these incidence rates. These criteria were used to ensure that the studies included in the analysis were directly relevant to the research question and that the results were comparable and interpretable. Exclusion criteria were duplicate data, incomplete data, studies that did not share variable and studies with a high risk of bias.

Information sources

The following information sources were used to conduct this meta-analysis: PubMed, EMBASE, Scopus, and the Cochrane Collaboration Library database. No date limit was specified during the search. In addition, a search was conducted within the reference lists of each of the original studies included in the analysis to ensure comprehensive coverage of the available literature.

Search methods for identification of studies

We used the following search terms to search all studies registers and databases: ((pelvic fracture AND urinary tract) OR (pelvic fracture AND bladder)) OR (pelvic fracture AND urethra). Two reviewers independently agreed on selection of eligible studies and achieved consensus on which studies to include.

Data extraction and data items

Regarding data extraction, two authors also independently reviewed the studies. An initial screening of titles and abstracts was performed to eliminate studies that were obviously outside the scope of the review. In cases of uncertainty based on title or abstract, the full text of each article was examined for further evaluation. If consensus was not reached, a third review author was asked to complete the data extraction form and discuss the article with the other two authors until consensus was reached. All disagreements were resolved by discussion. Data extraction was performed by two reviewers via an Excel spreadsheet. The baseline characteristics of each study were obtained: Study, type of study, region, period, number of participants, and number of patients with urinary tract injuries. The primary outcome was the incidence of urinary tract anomalies associated with pelvic fractures. The secondary outcomes were risk factors and characteristics of this condition including hemodynamic stability (number of patients who presented low systolic blood pressure (SBP) less than 90 mmHg), mechanism of injury, types of pelvic fracture, mortality, and other unplanned variables that were compared by at least two studies and were considered characteristics of interest by experts in the field.

Assessment of risk of bias in included studies

The risk of bias in the included studies was evaluated using the Methodological Index for Non-Randomized Studies[12]. A maximum score of 24 was assigned to comparative studies, while non-comparative studies were rated on a scale of 0-16. A score of 0-4 was considered very low quality, 5-7 as low quality, 8-12 as fair quality, and ≥ 13 as high quality for non-comparative studies. For comparative studies, a score of 0-6 was considered very low quality, 7-10 as low quality, 11-15 as fair quality, and ≥ 16 as high quality[12]. Two reviewers independently evaluated the studies, and in cases where there was a lack of consensus in the scoring, a third reviewer was consulted to resolve any discrepancies (Supplementary Table 1).

Assessment of results

For the statistical analysis, we used the Review Manager 5.4 software package provided by the Cochrane Collaboration. Pooled incidences with 95%CI were calculated using a random-effects model. Since the SE was not reported, we calculated it from the prevalence using the following formula: SE = √P (1 - P)/n and 95%CI = P ± 1.96 × SE, where P represents the prevalence[13]. To assess pooled incidences and risk factors, we used the generic inverse variance outcomes when they were given by the individual studies in terms of odds ratio (OR) or relative risks (RR) for dichotomous variables, and mean difference (MD) with 95%CI for continuous variables. We checked for heterogeneity using the I² test, where a value of 75% or higher was considered indicative of high heterogeneity. In cases where heterogeneity was present, we used the random-effects model to account for this variability[13].

Risk of bias across the studies

To assess the risk of bias across the studies, we used the Review Manager software package to conduct a visual inspection of the funnel plots and interpret them accordingly. Funnel plots are graphical representations of the relationship between effect size and sample size. They can be used to identify potential publication bias or other sources of heterogeneity across the studies. We visually inspected the funnel plots and interpreted any asymmetry as a potential indication of publication bias[14].

Additional analyses

To assess the robustness of our findings, we conducted a sensitivity analysis using the Review Manager 5.4 software package. Specifically, we eliminated the top-weight study from the comparisons in all outcomes to evaluate the consistency of the effect sizes. This analysis allowed us to determine the extent to which the results were influenced by any single study and to evaluate the overall robustness of the findings[12]. The results of individual studies that could not be compared for different reasons (lack of data or a data form incompatible with the statistical program) were reported during the reporting of the results. Subgroup analysis was performed to explore the heterogeneity of the studies, and such analysis used the location of urinary tract involvement. The same was done for studies that could differ in baseline characteristics so that they could be controlled.

RESULTS

Study selection

The initial search yielded 1385 results, from which review studies and case reports were eliminated, resulting in a total of 784 articles. After reviewing the titles and abstracts, eight articles met the inclusion criteria. After reviewing the references of the included articles, we then found two additional studies that met the inclusion criteria. Thus, 10 studies were included in the meta-analysis (Figure 1)[2,8,10,15-21].

Figure 1 Study selection flow diagram. This flow diagram illustrates the study selection process according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. It depicts the number of records identified through database searching, the number of records screened, the number of full-text articles assessed for eligibility, the number of studies included in the meta-analysis, and the reasons for exclusion at each stage.

Study characteristics

Table 1 shows the main characteristics of the included studies[2,8,10,15-21]. These 10 studies included a pool of 22700 patients. Eight studies were published in the United States, one in Egypt, and one in the United Kingdom. Seven articles were cohort studies, and one of the studies was prospective. The follow-up period varied among the studies, but all had at least 1 year of follow-up. Ages ranged from 12 to 59 years. Gender varied because some articles focused on a certain gender (two studies focused only on men, and one study focused only on women). Two studies focused on bladder injuries, two studies on urethral injuries, and six studies on the entire genitourinary tract. For the non-comparative studies, the quality of the studies was low (two studies) or very low (one study). For the comparative studies, one study presented low quality, four presented fair quality, and two presented high quality.

Table 1 Baseline characteristics of the ten included studies.

Ref.	Region	Type of study	Period	Age	Male	Patients, n	Urinary tract injury, n
Avey et al[17], 2006	United States	Retrospective cohort	1997-2003	37	448	783	36
Bjurlin et al[20], 2009	United States	Retrospective cohort	2001-2005	NA	NA	29936	1444
Bott et al[21], 2022	United Kingdom	Retrospective serie	1994-2005	59	177	177	5
Delaney et al[19], 2016	United States	Retrospective cohort	2010-2012	12	0	2639	81
Demetriades et al[8], 2002	United States	Retrospective cohort	1993-2000	37	937	1545	90
Hochberg et al[15], 1993	United States	Retrospective serie	1993	39	53	103	10
Johnsen et al[2], 2017	United States	Retrospective cohort	2000-2014	NA	3416	5518	233
Koraitim et al[16], 1996	Egypt	Prospective serie	1990-1992	31	203	203	51
Lowe et al[18], 1988	United States	Retrospective cohort	1979-1985	NA	405	405	21
Velazquez et al[10], 2020	United States	Retrospective cohort	2010-2014	35	NA	180931	6140

NA: Not available.

Outcomes

The incidence of urinary tract anomalies associated with pelvic fracture was 6.88% (95%CI: 6.20%-7.55%). Among the studies that could be compared, female sex was not a risk factor (OR 1.39, 95%CI: 0.22-8.94). In contrast, Demetriades et al[8] showed that male sex was an increased risk of urinary tract injury (RR 1.8 95%CI: 1.1-2.8; P = 0.01).

Regarding the mechanism of injury (Figure 2), vehicle accidents, motorcycle accidents, and pedestrian accidents were risk factors for urinary tract injury: (RR 1.08, 95%CI: 1.06-1.11; participants = 220251; studies = 4; I² = 21%), (RR 1.89, 95%CI: 1.78-2.00; participants = 219646; studies = 4; I² = 21%), and (RR 1.53, 95%CI: 1.20-1.95; participants = 219646; studies = 4; I² = 88%), respectively. In contrast, falls from height or cycling accidents were more frequent in the control group without urinary tract damage: (RR 0.30, 95%CI: 0.24-0.39; participants = 219646; studies = 4; I² = 64%) and (RR 0.46, 95%CI: 0.22-0.94; participants = 32575; studies = 2; I² = 0%), respectively.

Figure 2 Forest plots showing the association between mechanism of injury and urinary tract injury in patients with pelvic fractures. The forest plots display the relative risk (RR) of urinary tract injury for different mechanisms of injury. A: Vehicle accidents; B: Motorcycle accidents; C: Pedestrian accidents; D: Falls from height; E: Cycling accidents. The squares represent the point estimate of the RR for each study, with the size of the square proportional to the study's weight in the meta-analysis. The horizontal lines represent the 95%CI. The diamond represents the pooled RR, with its width representing the 95%CI.

Regarding individual studies, Hochberg and Stone[15], and Johnsen et al[2] showed similar proportions. Hochberg and Stone[15] showed 49% of urinary tract injuries in pelvic fractures were pedestrian accidents and up to 32% in vehicle and 7% in motorcycle accidents. Johnsen et al[2] showed 47% vehicle accidents, 17% motorcycle, and 8% pedestrian. Koraitim et al[16] observed that traffic accidents accounted for up to 71% of occurrences and falls from height for 25%. For Demetriades et al[8], motorcycle accidents were most commonly associated with urinary tract injuries.

Regarding hemodynamic instability, patients with urinary tract injury when in emergency departments did not present greater hemodynamic instability (OR 0.99, 95%CI: 0.03-36.08; studies = 3). Hochberg and Stone[15] observed that 23% of patients with urinary tract injury showed hypotension (less than 90 mmHg). There was also no difference with respect to the Glasgow Coma Scale (GSC) (OR 2.54, 95%CI: 0.60-10.69; studies = 2).

Regarding the type of fractures with a higher risk of urinary tract injury, acetabulum fractures did not show an increased risk (OR 0.84, 95%CI: 0.48-1.46; studies = 5) (Figure 3A). Pubic fractures did show a risk factor (OR 1.94, 95%CI: 1.09-3.44; studies = 4) (Figure 3B); however, when subgroup analysis was performed, pubic fractures were significantly more associated with specific urethral injury (OR 13.63, 95%CI: 4.84-38.35) vs complete urinary tract injury (OR 1.38, 95%CI: 0.91-2.10). Fractures of the ilium did not show an increased risk (OR 1.01, 95%CI: 0.69-1.46; studies = 4) (Figure 4A). Likewise, ischium fractures were not shown to be a risk factor (OR 1.01, 95%CI: 0.67-1.53; studies = 3) (Figure 4B). Pelvic ring disruption showed an increased incidence of associated urinary tract injury (OR 5.53, 95%CI: 4.67-6.54; studies = 3) (Figure 5A). Finally, innominate/pelvic rim fracture did not show an increased risk of associated urinary tract injury (OR 1.31, 95%CI: 0.72-2.38; studies = 2) (Figure 5B).

Figure 3 Forest plots showing the association between fracture type and urinary tract injury in patients with pelvic fractures. A: Acetabulum fracture; B: Pubic fracture. The squares represent the point estimate of the odds ratio (OR) for each study, with the size of the square proportional to the study's weight in the meta-analysis. The horizontal lines represent the 95%CI. The diamond represents the pooled OR, with its width representing the 95%CI. Pubic fracture analysis includes a subgroup analysis for urethral injury.

Figure 4 Forest plots showing the association between fracture type and urinary tract injury in patients with pelvic fractures. A: Ilium fracture; B: Ischium fracture. The squares represent the point estimate of the odds ratio (OR) for each study, with the size of the square proportional to the study's weight in the meta-analysis. The horizontal lines represent the 95%CI. The diamond represents the pooled OR, with its width representing the 95%CI.

Figure 5 Forest plots showing the association between fracture type and urinary tract injury in patients with pelvic fractures. A: Pelvic ring disruption; B: Innominate/pelvic rim fracture. The squares represent the point estimate of the odds ratio (OR) for each study, with the size of the square proportional to the study's weight in the meta-analysis. The horizontal lines represent the 95%CI. The diamond represents the pooled OR, with its width representing the 95%CI.

In relation to discharge, patients without urinary tract injury were more likely to discharge home (RR 0.79, 95%CI: 0.67-0.92; participants = 217007; studies = 2; I² = 93%) (Figure 6A), but there were no differences with respect to those discharged to nursing homes (OR 0.78, 95%CI: 0.60-1.01; participants = 217007; studies = 2; I² = 66%) (Figure 6B). Finally, mortality was higher in the group with associated urinary tract injuries (OR 1.92, 95%CI: 1.77-2.09; participants = 217007; studies = 2; I² = 0%) (Figure 6C).

Figure 6 Forest plots showing the association between urinary tract injury and discharge disposition/mortality in patients with pelvic fractures. A: Discharge home [relative risk (RR)]; B: Discharge to nursing home [odds ratio (OR)]; C: Mortality (OR). The squares represent the point estimate of the RR or OR for each study, with the size of the square proportional to the study's weight in the meta-analysis. The horizontal lines represent the 95%CI. The diamond represents the pooled RR or OR, with its width representing the 95%CI.

There were other variables analyzed by individual studies or series that did not compare the results. For one, macro- or microscopic hematuria was detected in 25% and 59% of patients, respectively, by Hochberg and Stone[15]. In the case of Avey et al[17] all patients with bladder rupture presented hematuria. Regarding the length of stay (LOS), Hochberg and Stone[15] observed a mean of 27 days (range 8 to 80 days). Moreover, Velazquez et al[10] observed significant differences with respect to LOS. Patients with urinary tract injury 14.5 days and without urinary tract injury 9.1 days (P < 0.01), with urinary tract injury patients spending an average of 8.5 days in the intensive care unit (ICU) vs 7.1 days for patients without associated urinary tract injuries (P < 0.01)[10]. Bjurlin et al[20] also observed differences between those with and without urinary tract injuries in terms of total LOS and ICU stay. In total LOS, those with urinary tract injuries had on average 10 days vs 6 days for those without such injuries; in ICU stay, those with urinary tract injuries had 3 days vs only 1 day on average for those without such injuries[20]. Finally, the number of patients undergoing surgical exploration was nine of 10 (90%) for bladder ruptures in the study by Hochberg and Stone[15], while Velazquez et al[10] observed that 1658 of 6140 (27%) patients with urinary tract injury underwent repair surgery.

Additional analyses

Regarding the sensitivity analysis, the variables shared by only two studies that were compromised when the study with the highest weight was eliminated and changed the direction of the overall results were innominate/pelvic rim fracture and discharge to nursing home. Pubic fracture also changed the direction of the overall results when the top-weighted study was removed (Figure 7). The publication bias analysis using funnel plots showed asymmetry, which indicated publication bias (Figure 8).

Figure 7 Forest plot showing sensitivity analysis for the association between pubic fracture and urinary tract injury. This forest plot illustrates the impact of removing the top-weighted study on the pooled odds ratio (OR) for the association between pubic fracture and urinary tract injury. The squares represent the point estimate of the OR for each study, with the size of the square proportional to the study's weight. The horizontal lines represent the 95%CI. The diamond represents the pooled OR, with its width representing the 95%CI.

Figure 8 Funnel plots assessing publication bias in the meta-analysis. These funnel plots examine the potential for publication bias in the analyses. A: Pedestrian accidents; B: Hemodynamic instability; C: Acetabular fracture. Asymmetry in the funnel plot may suggest publication bias. RR: Relative risk.

DISCUSSION

This study is a meta-analysis that examined the incidence and trends of urinary injuries related to pelvic fractures. The meta-analysis showed that the overall incidence of urinary tract injury associated with pelvic fracture was 6.88%. Vehicle accidents, motorcycle accidents, and pedestrian accidents were closely associated with urinary injury. Additionally, patients with urinary injury did not present greater hemodynamic instability. Also, pubic fractures together with pelvic ring disruptions were factors that increased the frequency of associated urinary injury. The quality of the non-comparative studies was low, but the quality was fair for most of the comparative studies. It is important not to underestimate the incidence of urinary injuries associated with pelvic fractures because previous studies warn of the associated morbidity[6].

With respect to the rupture or lesions of the bladder, in the studies that described these in isolation, the incidence observed was 7.15%. Extraperitoneal ruptures are produced by bone spicules or shearing although injuries by bone fragments explain only 35% of the cases[17]. In contrast, intraperitoneal injuries usually occur when the bladder is distended[5]. Approximately 30% of bladder ruptures are intraperitoneal and require surgical treatment[5].

With respect to urethral injuries, women are at lower risk due to the shorter length of the urethra and greater mobility because it is not attached to the pubis[22]. This meta-analysis, however, showed no differences with respect to gender when the results were compared. These injuries are believed to be the result of avulsion of the bulbomembranous urethra fixed to the urogenital diaphragm or injury by bony fragments and strongly associated with rupture of the anterior pelvic arch[10,17]. Although Lowe et al[18] observed that anterior arch fractures along with combined pubic or sacroiliac branch fractures could predict urethral injury[18], Koraitim et al[16] observed that sacroiliac fracture increased the risk of urethral injury.

Regarding the association of urinary tract injury with the type of pelvic fracture, not all available associations could be compared. Koraitim et al[16] showed that a Malgaigne pelvic fracture was associated with urethral injuries in their study due to the rupture of the posterior pelvic arch and its close relationship with the bulbomembranous urethra[16]. In this meta-analysis, pubic fractures increased the probability of urinary injury almost twofold because the bulbomembranous junction is firmly attached to the pubic arch; however, diastasis of the pubic symphysis and sacroiliac joint were independently associated with bladder rupture[23]. Basta et al[22]. concluded that urethral injury increased as symphysis diastasis or displacement of the fracture fragments of the inferomedial pubic bone increased[22]. although any type of fracture with sufficient force is capable of compressing urinary soft tissue. Pelvic ring disruption usually caused by vertical shearing was shown to be a risk factor for urinary injury associated with pelvic fracture. This is caused by stretching of the membranous urethra. Velazquez et al[10] stated that the more ruptured points in the ring, the greater the risk of urinary injuries. Pubic diastasis and pubic rami were also associated with urinary and gastrointestinal injury[10]. Associations between damage to different organs could not be compared, though. Sacroiliac fractures also could not be compared in this meta-analysis but are associated with sexual dysfunction[24].

Although it is logical to think that urinary injury is associated with a worse hemodynamic status, this result was not observed in this study. This is probably due to the low number of studies included. Velazquez et al[10] proposed that a SBP less than 90 mmHg is probably a direct reflection of combined urinary injury.

In relation to the mechanism of injury, it was observed that vehicle, motorcycle, and pedestrian accidents had higher probabilities of urinary injury. The findings have strong ramifications for the management of traumatic injury. Indeed, these patients with pelvic fractures due to high-risk mechanism carriers show an increased need for a high index of suspicion and pro-active assessment for urinary tract injuries; this would involve, for example, early imaging studies such as cystography or urethrography and early urology consultations. With early recognition and management of injuries, patient morbidity from long-term sequelae, such as incontinence, strictures, and sexual dysfunction, can greatly be reduced.; thus, when a patient presents with this type of mechanism of injury, medical professionals could further investigate whether the patient has a urinary tract injury. Likewise, knowing which type of fracture is most frequently associated with urinary tract injury is important so that medical professionals can pay more attention during examinations and avoid late diagnoses. In this study, the fractures most frequently associated with urinary tract injury were pubic fractures and pelvic ring disruptions.

Finally, mortality was higher in the group with associated urinary tract injuries. This finding is contrary to the hemodynamic instability outcome. This is probably due to the low number of studies included, and it could indicate that the destabilization of the patient with urinary tract injury occurs later than when the patient arrives at the emergency department, which is when the instability constants are measured in most studies by blood pressure. These results could also suggest that mortality is not related to urinary injury and is due to the association with other related injuries. However, the presence of urinary lesions may coincide with a torpid hospital evolution with increased morbidity and mortality[4,10]. It would be useful to include in future studies information on the moment of destabilization of patients with pelvic fractures.

The socioeconomic impact of these injuries is crucial to consider since such patients consume large amounts of resources due to longer hospital and ICU stays as a result of loss of mobility. In addition, the highest costs are those for rehabilitation work, mortality, and absenteeism since many of these patients are young and active[7].

This study had several limitations. For one, there is a dearth of studies focused on clinical signs that are able to detect the risk of urinary injury. Only one study analyzed this fact. Secondly, some data had to be estimated according to Cochrane criteria such as interquartile ranges or the use of percentages over the total number of patients. In addition, much information was extracted from the figures using WebPlotDigitizer. Some fractures with great clinical implications such as sacral or sacroiliac fractures could not be examined since some fractures were described in association with different fractures or not were directly evaluated by the studies. Studies that did not clearly state the type of fracture or combined fractures were eliminated from the analysis. Bladder, urethral, or whole urinary tract injuries were also analyzed together. Finally, different evaluation criteria were used for the GSC scale; in one study, fewer than eight criteria were used, and in another study, fewer than thirteen.

CONCLUSION

This meta-analysis showed that the overall incidence of urinary tract injury associated with pelvic fracture was 6.88%. It was also observed that the mechanism of injury of vehicle, motorcycle, and pedestrian accidents should suggest a greater probability of urinary injury. Similarly, pubic fractures and pelvic ring disruptions are more frequently associated with urinary tract injury. Early diagnosis is important since a higher mortality rate was observed in these patients with longer hospital stays. Recognition of these associations can help traumatologists and urologists to identify earlier subjects at risk of urethral injury. Finally, this study encourages medical professionals to be clear about the mechanism of action, to be alert to specific fractures, or to request further complementary tests to rule out early urinary tract injuries.