I. Overview: The male urethra is divided into anterior and posterior parts by the urogenital diaphragm. The etiology, trauma mechanism, diagnosis and treatment of anterior and posterior urethral injuries are different, among which the treatment of posterior urethral injuries is more complicated and the selection of treatment methods is still widely controversial. Mamdouh reported that the incidence of pelvic fracture with urethral rupture is about 1.6-25% (average 9.9%), and the occurrence of urethral injury is closely related to the type of pelvic fracture, especially the unstable fracture. (1) According to the stability of the pelvis, it can be divided into stable and unstable fractures, among which stable fractures include three or less fractures of the pubic-sciatic branch, isolated iliac fractures, avulsion fractures of the pelvic muscle attachment and sacral fractures; unstable fractures include straddle fractures (four fractures of the pubic-sciatic branch) and two simultaneous fractures of the anterior and posterior arches of the pelvic ring. fracture. (2) There are three types of fractures according to the direction of force: anterior-posterior compression, lateral compression and vertical shear; the first two can be stable or unstable fractures, while vertical shear is mostly unstable fractures; this typing method allows the physician to clarify the mechanism of injury, so that the opposite force can be used to reset the fracture during treatment. Special attention needs to be paid to the following two types of fractures: (1) straddle fracture: that is, a four-branch fracture of the pubic-sciatic branch, caused mainly by lateral compression and rarely by anterior-posterior compression. According to Koraitim, the odds of urethral injury in straddle fractures are 3.85 times higher than in other types of pelvic fractures, and strong lateral violence sometimes causes both sacral and iliac fractures or Sacroiliac joint separation, and straddle fractures combined with sacroiliac joint separation are most likely to cause urethral injury, which is 24 times more likely to occur than other types of pelvic fractures. (2) Malgaigne fracture: i.e., separation of the pubic symphysis or fracture of one pubic sciatic branch combined with fracture of the posterior arch of the ipsilateral pelvic ring (fracture of the sacrum, sacroiliac joint or iliac bone), caused by vertical violence, vertical shear force causes the affected hemipelvis to be displaced posteriorly and upward. Malgaigne fractures are 3.4 times more likely to be associated with urethral injury than other types of pelvic fractures and are the most common type of pelvic fracture causing urethral injury. It has long been thought that the shear violence of a pelvic fracture causes the apical prostate to tear away from the urogenital diaphragm, causing the urethra to rupture at the junction of the membranous and prostatic portions. However, recent studies have shown that the above view is wrong. First of all, autopsy revealed that there was no obvious superior urogenital diaphragm, which separates the urethral sphincter from the prostate, and that the urethral sphincter does not only wrap horizontally around the membranous urethra, but it also enters upward into the prostate and even reaches the bladder neck, wrapping around the anterior and bilateral surfaces of the prostate with thin bundles of muscle fibers, and downward into the inferior urogenital diaphragm, without entering the bulbous urethra]. Therefore, the abrupt interruption of the tough urogenital subdiaphragm fascia (which can be renamed as perineal fascia) and urethral sphincter at the bulb urethra makes the junction of the urethra bulb and membrane, rather than the junction of the prostate and membrane, a weak urethral point, which makes it vulnerable to urethral injury. Second, a large number of clinical urographs have also shown that the extent of urinary extravasation in most urethral ruptures is not confined above the urogenital diaphragm, but extends below the urogenital diaphragm and around the bulbar urethra. Again, when patients with pelvic fracture urethral injuries underwent stage II urethral reconstruction, it was found that scar formation included not only the urogenital diaphragm, but also the proximal bulbous urethra. The view that the bulbomembranous urethral junction is weaker is consistent with the clinical view that type III urethral rupture (membrane urethral rupture with a tear in the urogenital diaphragm and injury extending to the proximal bulbomembranous urethra) is the most common, whereas type II urethral rupture (membrane urethra ruptured above the urogenital diaphragm with the urogenital diaphragm intact) is rarer. When the pelvis is fractured, the soft tissues within it, such as the bladder and prostate, are simultaneously impacted and squeezed. Since the bladder and prostate are loosely attached to the bony pelvis, they are bound to move upward when compressed, and the sudden movement causes the membranous urethra to be violently stretched, and if the pubic prostatic ligament ruptures at this time, it will provide a certain range of mobility to the membranous urethra, but if the violence continues, the urethra will inevitably move at the weak point, i.e. If the violence continues, the urethra will inevitably rupture partially or completely at the junction of the bulbous and membranous urethra. The urethral rupture displaces the prostate upward, while the hematoma formed by the rupture of the retropubic plexus displaces the prostate backward. Injuries to the bladder neck and urethral prostate are often caused by puncture wounds to the broken ends of sharp fractures. Since the prostate gland in children is small and does not provide protection to the above areas, the above injuries are seen almost exclusively in children, and there is often a longitudinal fracture in the anterior part of the prostate. (B) anterior urethral injury: anterior urethral injury can be divided into external injury and medical injury, external injury includes penetrating injuries (such as gunshot wounds, stab wounds) and blunt injuries (such as straddling injuries, penile fractures), a few cases caused by the insertion of foreign objects in the urethra, such as the patient has a perverted libido, psychological disorders or other incidental causes. Medically induced injuries are mainly caused by intraurethral instrumentation, especially for a long time, and another cause is caused by pancreatic enzymes in the urine that damage the urethral mucosa after pancreatic transplantation. Injuries to the bulbous urethra are mainly caused by straddling injuries, when the perineum is straddled by a hard object such as a bicycle beam or fence, the bulbous urethra is crushed between the hard object and the inferior border of the pubic symphysis, resulting in contusion or fracture. The incidence of penile fracture complicated by urethral injury is about 10-20%. Third, clinical manifestations and diagnosis: If there is a history of corresponding trauma such as pelvic fracture or riding span injury, the possibility of urethral injury should be highly suspected. In the past, the diagnosis of urethral rupture mainly relied on the triad of signs: (1) blood overflow from the urethra; (2) inability to urinate on its own; (3) bladder filling. A trial catheter was also used to assist in the diagnosis, and if the catheter could not be inserted into the bladder, a urethral rupture was considered. [11] It is now believed that the trial catheterization method should be discarded because it can convert a partial urethral rupture to a complete rupture and also increases the chance of hematoma infection if the catheter is inserted into a paraprostatic hematoma. Retrograde urethrography is considered the “cornerstone” of the diagnosis of urethral injury [1] and should be performed first in all patients with suspected urethral injury. The patient is placed in a 45-degree oblique position with the penis perpendicular to the femur, but not all patients can be placed in this position, so for these patients, they can be placed in a horizontal position with the penis pulled down vertically. Urethrography not only clarifies whether the urethra is injured or not, but also whether it is partially or completely broken and what type of injury it is. Prior to 1977, urethral injuries were usually divided into anterior and posterior urethral injuries based on anatomy and two different mechanisms of injury, i.e., posterior urethral injuries were mainly caused by pelvic crush injuries and anterior urethral injuries were mainly caused by straddling injuries. Due to the promotion of preoperative urography, many scholars found that strictly posterior urethral injuries (i.e., urethral injuries above the urogenital diaphragm) were rare, while bulbar urethral rupture combined with urogenital diaphragm rupture was the most common, and the latter injury was no longer limited to the posterior urethra but had extended to the bulbar urethra. Therefore, in 1977, Colapinto and McCallum suggested three types of posterior urethral injuries: type I – posterior urethral traction thinning without rupture (caused by rupture of the pubic prostatic ligament, upward displacement of the prostate gland pulling on the urethra, and compression of the urethra by a paraurethral hematoma); type II – rupture of the membranous urethra above the urogenital diaphragm (extravasation of contrast into the extraperitoneal space of the pelvis, above the intact membranous (extravasation of contrast into the perineum below the urogenital diaphragm and around the bulbous urethra); type III – rupture of the membranous urethra with injury extending down to the proximal bulbous urethra combined with rupture of the urogenital diaphragm (extravasation of contrast into the perineum below the urogenital diaphragm and around the bulbous urethra). Because type III urethral injuries are not purely posterior urethral injuries, but rather a combination of anterior and posterior urethral injuries, and because this typology does not include proximal urethral injuries caused by bladder neck injuries, Goldman proposed a revised scheme in 1997, which added type IV – proximal urethral injuries caused by bladder neck injuries; type IVA – bladder base injuries (extravasation of contrast around the urethra, making it similar to type IV injury); and type V – simple anterior urethral injury. First, it should be determined whether the urethra is partially or completely broken. When the urethra is completely broken, extravasation of contrast and interruption of the continuity of the urethra can be seen, and no contrast appears in the bladder. Any amount of contrast entering the bladder suggests an incomplete urethral break; second, the type of urethral injury should be clarified. Rectal palpation should be used as a routine, not only to exclude rectal injury, but also to probe the prostate, if the prostate is floating, it means that the urethra has been completely ruptured. For anterior urethral injury, it is very important to place the patient in an oblique position during urography, the anterior-posterior position of the film will create the illusion of shortened urethra, and it is better to inject the contrast agent through the catheter rather than with a syringe (the catheter balloon is placed in the navicular fossa, and the balloon is filled with 1 to 2 ml of liquid to fix it), so that the doctor’s hand is not exposed to the X-ray, which affects the effect of the film. Fourth, treatment: (a) posterior urethral injury: For patients with partial urethral rupture, simple suprapubic cystostomy should be the first choice, [9] the fistula is left in place until the urethra heals, at which time the urethrography should be free of extravasation of contrast, and if urination is unobstructed after clamping the fistula, the fistula can be removed, and if there is scar stenosis, urethral dilatation or endoscopic urethrotomy with scarring is feasible and effective. For complete urethral dissection, the choice of treatment remains widely controversial, with the following three main approaches: (1) early urethral anastomosis (2) urethral commissurotomy (3) early cystostomy + stage II urethral reconstruction. postoperative complications, mainly urethral stricture, urinary incontinence and erectile dysfunction (ED), are present to varying degrees in all three approaches. mamdouh, in an analysis of 871 patients treated with early urethral anastomosis, the incidence of all three complications was higher, 49% (stricture), 21% (incontinence) and 56% (ED), respectively; whereas in patients who underwent cystostomy only, stricture occurred in almost all postoperative cases (97%), and stage II urethral reconstruction was inevitable, but the incidence of incontinence and ED was lower, 4% and 19%, respectively; in patients who underwent concomitant The incidence of urethral stricture was half that of simple fistula (53%), but the incidence of ED was double that of simple fistula (36%), and the incidence of urinary incontinence was similar (5%).0 In an analysis of 92 patients undergoing stage II urethral reconstruction, S. Dmark concluded that this procedure did not increase the incidence of ED, and that damage to the erectile nerve immediately below the pelvic fracture, especially in the case of fractures of the pubic sciatic branch, was the main cause of ED. It is the main cause of ED, so many scholars rank this method as the first choice and even consider it the gold standard for the treatment of posterior urethral rupture. However, Leonid pointed out after a controlled study of two groups of patients that urethral commissurotomy does not increase the incidence of ED, which is caused by the trauma itself, and recently showed with MRI and Doppler ultrasonography that 80% of patients who developed ED had severe damage to their corpus cavernosum and surrounding tissues, so the development of ED may be vascular rather than neurogenic. The recent advent of endoscopic and fluoroscopic angiographic rendezvous has increased the vitality of this method by making intraoperative injuries less severe. (1) Early urethral anastomosis: It was the first method used to treat posterior urethral rupture, first used by Young in 1929, with the disadvantage that the incidence of surgical complications is higher, significantly higher than the other two methods. The reason for this is that this method inevitably involves exploring the retropubic space and removing the hematoma, resulting in the loss of the “filling” effect of the retropubic hematoma, plus the dissection of the urethral dissection, both of which can cause displacement of the prostate gland, resulting in damage to the erectile nerve immediately adjacent to it, resulting in ED; and the dissection of the urethral dissection, which can also cause damage to the internal The dissection of the urethral dissection can also cause impaired function of the internal sphincter, resulting in urinary incontinence. In addition, the difficult surgical operation, the lithotomy position will increase the displacement and injury of the pelvis, and the incidence of urethral stricture is high, so many scholars believe that this method should be abandoned. Mundy believes that the surgery should be performed 7-10 days after the trauma, when the patient is basically stable, there is no active bleeding, the surgical field is clear, and there is no fibrous scar. (2) Urethral rendezvous: first used by Ormond and Cothran in 1934 and became prevalent 30 years ago. In order to make the urethral dissection close, traction repositioning can be done. The commonly used traction methods are balloon catheter traction and prostate suture fixation traction, the former method will compress the bladder neck causing damage to the internal urethral sphincter located in this part and increasing the incidence of urinary incontinence, which is now abandoned, while the latter method requires exposure of the retropubic space and has the potential to damage blood vessels and erectile nerves leading to ED. In type III urethral rupture, the urethral diaphragm is torn and the distal end of the urethral rupture is not fixed to the urogenital diaphragm, so the two ends may be poorly aligned during traction, and even angulation and rotation may occur. Use of a catheter with a lateral hole to facilitate drainage of secretions in the urethra and to reduce the chance of infection and stricture. This procedure is still used by many physicians because it is safer and easier to perform than early anastomosis and also avoids the pain of a phase II procedure after cystostomy alone, and it also allows the urethral dissection to be close together so that even if strictures occur, they can be easily repaired. Recently, endoscopic rendezvous is becoming a trend with the advantages of direct vision, less trauma, easy operation and fewer complications, which can ensure that the catheter does pass through the two broken ends of the urethra, but requires a soft cystoscope. (3) Early cystostomy + stage II urethral reconstruction: Since the complication rate of early surgery are higher, Johanson first proposed in 1953 that early cystostomy only and urethral reconstruction after 3-6 months can reduce the incidence of complications, when the post-pubic hematoma has been absorbed, the pelvic fracture and general condition have been stabilized, and the surgery can be performed with ease. The disadvantage of this procedure is that due to the retraction of the two broken ends of the urethra, especially the proximal urethra retracting upward into the pelvis, the urethral stricture is often several centimeters long, which makes the reconstruction of the urethra difficult. The function of the bladder neck should be evaluated before stage II surgery, as the function of the external sphincter is often impaired due to trauma, and how well the bladder neck functions determines the incidence of postoperative urinary incontinence. s. Macdiarmid believes that the majority of patients have normal bladder neck function and do not require surgical treatment. The right amount of contrast (around 100 ml) is essential for the correct evaluation of bladder neck function. Too much contrast can cause contraction of the detrusor muscle, thus creating the illusion of an open bladder neck, while too little contrast is not enough to dilate the bladder neck, both of which can lead to an incorrect diagnosis. If the cystogram shows a closed bladder neck, it is considered to be functioning normally. If the bladder neck is persistently open, a transstomy cystoscopy is also required, and only patients with a definite scar or fissure in the bladder neck can be diagnosed with impaired bladder neck function, and a functional reconstruction of the bladder neck is required at the same time for stage II surgery. Christophe concluded from a review of 15 patients that if the bladder neck and prostate If the open length of the proximal urethra exceeds 1.5 cm and a scar is seen on the anterior wall of the bladder neck, the chance of postoperative incontinence is greatly increased if no bladder neck repair is done. There are two methods of posterior urethral reconstruction, namely “end-to-end anastomosis” and “graft repair”, and A.R. mundg compared the efficacy of both and concluded that “end-to-end anastomosis” has a significantly lower complication rate than “graft repair”. Therefore, it is emphasized that any length of posterior urethral defect should be treated by anastomosis, because by freeing the anterior urethra and wedge excision of the inferior border of the pubic symphysis, the inferior pubic curve of the urethra can be straightened and the urethra can be lengthened by more than 10-12 cm, which is sufficient to make the urethral section anastomosed under no tension. The choice of repair is appropriate only if the anterior urethra is also damaged. (B) Anterior urethral injury: For patients with urethral contusion, treatment is relatively simple, and a catheter can be left in place for 10 to 14 days, and excretory urethrography should be done after extubation. For partial urethral rupture or minor urethral injury, trial catheterization can be considered, with a thin catheter gently inserted into the urethra, and if unsuccessful, suprapubic cystostomy is performed. In patients with complete urethral rupture or severe injury, treatment remains controversial, i.e. whether to perform early repair, early urethral meeting or cystostomy + stage II urethral reconstruction. Recent studies have shown that early repair is preferable for penetrating injuries because supporting tissues such as the corpus cavernosum are already damaged and will produce severe strictures if not repaired early. For urethral injuries caused by penile fractures early repair should be done to avoid penile deformation and painful erections. For blunt urethral injuries such as straddle injuries, it is recommended to simply do a cystostomy and stage II urethral reconstruction because the patient’s cavernous body and soft tissues are extensively damaged, making early repair very difficult. For patients with urethral strictures less than 2.5 cm in length, end-to-end urethral anastomosis is feasible, with complete excision of scar tissue and freeing of the urethral section to ensure a tension-free anastomosis; for patients with urethral strictures greater than 2.5 cm in length, urethral replacement material repair is recommended, which includes penile skin, bladder mucosa, and even skin of the upper arm, abdomen, and neck, with a success rate of more than 85%. J. Hernandez reported 13 cases of complex bulbar urethral strictures treated with buccal mucosa graft with satisfactory results. The etiology and mechanism of posterior and anterior urethral injuries are different. Posterior urethral injuries are mainly caused by pelvic fractures, especially by unstable fractures such as straddle fractures and Malgaigne fractures, while anterior urethral injuries are mainly caused by straddle injuries and penile fractures. Urethrography is the main method to diagnose urethral rupture and to make a staging diagnosis. There are three main treatment methods for posterior urethral injury: (1) early urethral anastomosis (2) urethral commissurotomy (3) early cystostomy + stage II urethral reconstruction, of which early urethral anastomosis has been rarely used due to many complications, the latter two methods have their advantages and disadvantages, for patients with obvious displacement of the urethral dissection, it is better to choose urethral commissurotomy, which can make the dissection close by traction so as not to produce a longer scar stenosis. For patients with very close urethral dissection ends, early cystostomy + stage II urethral reconstruction can be chosen. If available, transendoscopic rendezvous can be done, with efficacy to be further observed. For anterior urethral injuries, such as those caused by penetrating injuries or penile fractures, early repair should be done to avoid large scarring or penile deformation, while for blunt injuries such as riding span injuries, cystostomy alone is recommended, and urethral reconstruction is done in stage II. Regarding the retention time of postoperative catheter, it is generally 4-8 weeks, subject to no extravasation of urine. If there is no extravasation of urine in urethrography, it means that the urethral epithelium has covered the trauma and the catheter can be removed.