Epidemiologic study of bladder and urethral injury in Korea: A nationwide population-based study

Genitourinary trauma is not a common type of injury. Such trauma not only causes urinary tract injury but also damages other organs. In particular, injury to the urinary bladder and urethra, or the lower urinary tract, tends to be less frequent than upper urinary tract injury, and commonly occurs in conjunction with pelvic bone fracture or other pelvic organ injuries [1]. However, in addition to trauma-induced injury, bladder injuries are caused by pelvic organ surgery, such as hysterectomy and colorectal surgery, and urethral injuries are related to benign prostatic hyperplasia and insertion of a Foley catheter in males.

Although the basic mechanisms of lower urinary tract injuries (LUTIs) have been known for several decades [2], the management of these injuries has changed. The development of endoscopy played a key role in the primary realignment of urethral injuries [3]; in addition, the increased application of laparoscopy in the urological field and the development of barbed sutures have popularized single-layer suturing for bladder repair [4, 5]. Accurate treatment is important as incorrect treatment of LUTI can cause serious adverse effects such as urethral stricture, urinary tract infection, and urosepsis. Therefore, it is necessary to determine the incidence and treatment trends of LUTIs. However, accurate statistical data have not been reported in Korea.

Korea has established a national health insurance system; more than 99% of the nation’s population receive health insurance, and all their records are accessible. However, the incidence or trend of bladder or urethral injury in Korea has not yet been reported. The present study aimed to analyze national data from the National Health Insurance Service (NHIS) database in South Korea reported between 2012 and 2016 and to document the gross occurrence and rate of bladder and urethral injury stratified by age, sex, and accompanying injuries or causes. In addition, the incidence of bladder and urethral injuries was quantified to evaluate whether the incidence changed over time. Our hypotheses were 1) the incidence of bladder and urethral injuries has increased over time; 2) the injuries may be related to pelvic bone fracture, but a difference might be observed according to the fracture site; and 3) there are differences from previous reports in Western countries as few gun accidents have occurred in Korea.

We investigated the incidence of bladder and urethral injuries and their causes in Korea within a 5-year period. Overall bladder injury did not tend to increase over time, whereas bladder injury in female slightly increased. By contrast, the overall incidence of urethral injury gradually increased. As reported previously, urethral injury occurs more frequently in male than in female, but bladder injury occurs more frequently in female.

The major cause of LUTI is blunt trauma. Injuries to the bladder (60%–90%) and posterior urethra (75%) are mainly associated with pelvic fractures. Both bladder and urethral injuries occurred in 4.1% of the study participants. Trauma to the bulbar urethra is most commonly caused by a straddle injury. Injuries to the penile urethra are most frequently associated with penile fractures. Penetrating injuries, mostly gunshot wounds, can occur throughout the lower urinary tract, but are rare in the civilian setting. The incidence of bladder injury did not increase, whereas that of urethral injury increased. Urethral injuries are common in men which may be due to various Foley catheter–induced urethral injuries in older men. Urethral injuries may not be considered a serious problem because they occur in only 3 of 1,000 catheterized patients [7]. However, in other countries, catheter-related urethral injury has been reported to cause several problems, such as urosepsis and acute renal failure, and contributes to increased medical costs [8]. In the era of the aging of the population, the incidence of iatrogenic urethral injury caused by insertion of catheters will likely continue to increase; therefore, countermeasures for this injury are urgently needed. Many efforts have been made to reduce catheter-related injuries [9].

Bladder injuries were found to be common among women in their 30s and 40s, and were most likely iatrogenic injuries caused by obstetrics and gynecology surgery. The bladder is one of the most commonly injured organs during an obstetric surgery, such as cesarean delivery or hysterectomy [10]. The probability of bladder injury among cesarean sections is reported to be 0.28%, and bladder injury occurs in 1.38% of patients undergoing laparoscopic vaginal hysterectomy [11, 12]. As can be seen from our results, hysterectomy and cesarean section accounted for 22% and 1.5% of bladder injury cases, respectively. In particular, Korean women have a high preference for cesarean section; more than 40% of all births are performed through cesarean section, and maternal age and the incidence of placenta previa have also increased as a result of cesarean section [13]. In Korea, many obstetrics and gynecology surgeries are performed laparoscopically, and the possibility of bladder injury could be higher in laparoscopic surgery than in open surgery [12].

Although the incidence of genitourinary injuries is similar to the incidences of the three common types of pelvic fractures, certain fracture subtypes are known to place the genitourinary system at greater risk for injury, particularly straddle fractures. From a clinical perspective, the stability of a pelvic fracture is more useful in determining the likelihood of urethral injury. When pelvic fractures are categorized as stable, partially unstable, or unstable, the associated incidence of these fractures rises as the stability declines. In our results, pubis fractures were more frequent than acetabulum or ilium fractures, which are both pelvic bone fractures. Pelvic bone fractures are generally caused by high-energy injuries, such as car accidents or falls, and patients with these fractures are at risk for bladder and urethral injuries [14]. Injuries caused by pelvic fracture are difficult to treat and tend to recur and cause recurrent strictures. According to the guidelines, primary realignment or suprapubic cystostomy is required in patients with urethral injury. It is recommended that urethroplasty be performed 3 to 6 months after urethral injury [14]. However, our study findings suggest that most of the surgical treatments after urethral injury were performed within 1 month of the injury, and most of the surgeries were primary realignment or urethral dilation. The frequency of primary urethroplasty within 1 month was very low. This may be because our research included not only urethral injuries caused by pelvic bone fractures, but also minor injuries caused by self-removal of a Foley catheter or catheterization-related iatrogenic injury. Iatrogenic urethral injury is commonly associated with the insertion of a urethral catheter [15, 16]. In fact, urethral injury occurs more frequently in older patients. This is presumed to be because the chances of Foley catheter insertion increase as a result of hospitalization or surgery as age increases. In addition, because safety equipment and automobile safety have recently improved and the prevalence of negligent accidents has decreased, fewer injuries are caused by major accidents, and urethral injury itself has become relatively rare [17]. Nevertheless, the most common injuries associated with urethral injury, as revealed in this study, are abdominal and pelvic organ injuries; thus, we believe that the proportion of urethral injury due to traffic accidents remains high.

Our study has several limitations. First, it was difficult to determine the exact cause or severity of the injury because individual patient records were not reviewed. Hence, we relied on the prescription and diagnoses recorded in the NHIS database, which could lead to several errors and unintended results. Likewise, access to some information was limited; for example, in the case of iatrogenic injury, the exact cause was unknown. However, since most Koreans are covered by the NHIS, we believe that this is the first meaningful study to examine overall trends in urinary bladder and urethral injuries and their causes in Korea.

We reported the most recent incidences of bladder and urethral injuries in Korea using data from the national administrative database. Our data suggest that the incidence of urethral injury increased continuously throughout the years, whereas that of bladder injury remained unchanged. The incidence of bladder injury is higher in female owing to pelvic surgeries, including hysterectomy. The incidence of urethral injury remained high owing to the increase in the proportion of older male, who commonly obtained these types of injuries. We believe that these findings will help to determine future trends in LUTI and the direction of treatment.