Ureteral injury

　　1. Traumatic injury

　　1. Penetrating injury is the most common cause of ureteral injury:It is mainly caused by gunshot wounds or sharp instrument incisions; non-penetrating injuries are rare and often occur in traffic accidents or high-altitude falls. They often occur during pelvic or retroperitoneal surgery, such as colectomy, rectal resection, hysterectomy, and major vascular surgery. Due to the complex anatomy of the aforementioned sites, unclear surgical fields, hurried hemostasis, large-scale clamping, and ligation, it is easy to inadvertently injure the ureter.

　　2. Iatrogenic injury

　　1. Surgical injury:In operations on the lower abdomen or pelvis, injury to the lower third of the ureter is most common, and procedures such as retrograde ureteral catheterization, dilation, and stone extraction via cystoscopy can all lead to ureteral injury. When the ureter is narrowed, twisted, adherent, or inflamed, it may also be torn or even pulled apart. Gynecological surgery is the most common, accounting for more than 50% of iatrogenic injuries.

　　2. Instrument injury during examination:Commonly seen in ureteral catheterization, lithotripsy, ureteroscopy, etc., causing ureteral perforation or tearing.

　　3. Radioactive injury:High-intensity radioactive substances can cause congestion, edema, and inflammation of the ureter and surrounding tissues, eventually leading to stricture due to local scar fibrosis adhesion.

　　1. Ureteral stricture:Ureteral catheterization, dilation, or placement of a double-J ureteral stent drainage tube (F6) can be attempted, and the duration of retention is determined according to different conditions. If the stricture is severe or the tube placement is not successful, surgery should be performed according to specific conditions, including ureteral perinephric adhesiolysis or resection of the stricture segment. If complete ureteral obstruction cannot be temporarily relieved, a nephrostomy can be performed first, followed by ureteral repair 1 to 2 months later.

　　2. Urinary fistula:About 3 months after the occurrence of ureteral skin fistula or ureteral vaginal fistula, the inflammatory reaction caused by wound edema, urinary extravasation, and infection subsides. If the patient's general condition permits, ureteral repair should be performed, and the proximal ureter should generally be found, freed, and anastomosed with the bladder or bladder wall flap.

　　3. Others:For severe renal hydronephrosis or infection caused by ureteral stricture, severe renal function impairment or loss, if the contralateral kidney is normal, nephrectomy can be performed.

　　Ureteral injuries caused by penetrating injuries often have obvious associated injuries. The incidence of injury to these tissues and organs is in the order of small intestine, colon, liver, pancreas, bladder, duodenum, rectum, and large blood vessels. In 11 cases of ureteral mid-segment gunshot wounds, 6 cases had associated iliac vein injury. Blunt ureteral injury is almost always accompanied by fractures and/or renal, bladder, and other visceral rupture and contusion.

　　The clinical manifestations of ureteral injury depend on the time of detection, unilateral or bilateral injury, the presence or absence of infection, and the time and location of urinary fistula occurrence.

　　1. Medical history:History of pelvic surgery and ureteral intraluminal instrument operation injury, or severe penetrating injury history, including radical total hysterectomy, massive ovarian tumor resection, colorectal or rectal cancer radical surgery, and retroperitoneal fibrosis release surgery, etc.

　　2. Lumbar pain:After the ureter is ligated or clamped and damaged, due to complete and partial obstruction of the ureter, renal and ureteral hydronephrosis may occur, causing lumbar swelling and pain. During physical examination, there is tenderness and percussion pain in the affected renal area, and the upper abdomen can be palpated for pain and enlarged kidneys.

　　3. Urinary fistula or urinary extravasation:If the ureteral ligation or incision is not detected in time during surgery, postoperative urinary leakage at the incision, vaginal leakage, peritoneal urine collection, or abdominal cystic mass may occur.

　　4. Anuria or hematuria:After bilateral ureteral rupture or complete ligation, symptoms of anuria may occur. Such injuries are easy to detect in time. In addition, some patients may also experience hematuria; however, the absence of hematuria does not exclude the possibility of ureteral injury.

　　5. Fever:After ureteral injury, due to the unobstructed urine drainage or urine leakage and other conditions, secondary infection or local tissue necrosis may occur, at which time symptoms such as chills and fever may appear. Abdominal peritonitis symptoms may also appear when urine渗入 the abdominal cavity.

　　Due to the non-specific nature of early symptoms and signs, the diagnosis of ureteral injury requires high vigilance. ≥30% of patients do not have hematuria. First, intravenous urography should be performed. If the results of the urography cannot reach a conclusion, retrograde ureteropelvic urography should be performed. Occasionally, the diagnosis is made during abdominal exploration in the operating room. If the diagnosis is not made in time, clinical manifestations may include intestinal obstruction, urine leakage, urinary tract obstruction, anuria, and sepsis.

　　One, key points for preventing ureteral injury during surgery:

　　1. First and foremost, it is necessary to be familiar with the anatomical relationship between the ureter and adjacent organs, especially the above-mentioned vulnerable areas.

　　2. When cutting the lateral peritoneum of the sigmoid colon, the incision on the left posterior peritoneum should be on the lateral side of the ureter, and the incision on the right lateral peritoneum of the pelvic sigmoid colon should be on the medial side of the ureter.

　　3. Before ligating the inferior mesenteric artery, the left ureter should be found at the bifurcation of the left common iliac artery, and the right ureter should be found on the right side. Then, continue to expose upwards to the root of the sigmoid colon mesentery, and then guide the left ureter laterally. Under direct vision, ligate the inferior mesenteric artery to avoid ureteral injury.

　　4. Before handling the lateral rectal ligaments, the lower segment of the pelvic ureter and the bladder should be pulled away. If necessary, both ureters can be exposed downwards to the bladder, and the rectum should be pulled upwards to the opposite side. In direct vision, the lateral ligaments close to the pelvic wall should be bundled and cut.

　　5. It is always necessary to clearly distinguish the anatomical layers during surgery, operate gently, and carefully separate to avoid large ligation. Blind clamping for hemostasis should be avoided, otherwise, it may cause damage to the ureter. It should always be noted that the ureter may be adhered to the mesocolon and pulled up. Therefore, it is necessary to confirm that it is not the ureter before cutting the mesenteric vessels to ligate and cut them.

　　6. If the tumor is large and fixed, has a history of pelvic inflammation, has undergone pelvic or lower abdominal surgery, or has a history of pelvic radiotherapy, a urinary system造影 should be performed before surgery to understand whether the ureter has shifted, deformed, or has other lesions. If necessary, further cystoscopy and retrograde ureteral catheterization can be performed to facilitate the identification of the ureter during surgery. It is possible to first expose the normal ureterous location during surgery and then track and protect it according to its course.

　　7. In order to minimize the damage to the ureteral nutrient vessels, the ureter should only be exposed and not mobilized during surgery. If mobilization is necessary, it should not exceed 10cm, and attention must be paid to maintain the integrity of its adventitia. Otherwise, the blood supply of the ureter will be damaged. This is because the blood supply of the ureter is polyclonal, with different blood sources at different locations. Due to the variable blood source and the small anastomotic branches of some ureteral arteries, if the mobilization range is too large during ureteral surgery, it can affect the blood supply of the ureter, posing a risk of local ischemia and necrosis. Since the arteries supplying blood to the ureter are mostly from the inside, the ureter should be mobilized on the lateral side during surgery to reduce the damage to the blood supply.

　　8. When suturing the pelvic floor peritoneum, the ureter should be seen and avoided.

　　9. Before closing the abdomen at the end of the operation, the integrity of both ureters should be checked again to identify and repair problems in a timely manner. Otherwise, serious consequences may occur postoperatively, and it will be difficult to deal with.

　　Secondly, early repair should be done for ureteral injury:

　　1. Ensure patency, protect renal function. Urine extravasation should be thoroughly drained to avoid secondary infection. For mild ureteral mucosal injury, hemostatic agents and antibacterial drugs can be used, and symptoms should be closely observed. Small perforations that can be inserted and retained with appropriate ureteral stents can be expected to heal spontaneously.

　　90% of ureteral injuries caused by external violence manifest as microscopic hematuria, and for ureteral injuries caused by other reasons, urine tests and other examinations have little help in diagnosis, unless there is bilateral ureteral obstruction, otherwise, the level of blood creatinine is normal.

　　1. Intravenous urography:More than 95% of ureteral injuries can be diagnosed by intravenous urography, 50% can locate the level of ureteral injury, which can manifest as complete obstruction of the ureter; ureteral twisting or angulation; ureteral rupture, perforation, which can manifest as extravasation of contrast agent, and dilatation of the renal pelvis and ureter above the lesion.

　　2. Retrograde ureteral catheterization and pyeloureteral imaging:When intravenous pyelography cannot make a clear diagnosis or there is doubt, it should be combined with retrograde ureteral catheterization and pyeloureteral imaging to make a clear diagnosis.

　　3. Ultrasound examination:It can detect hydronephrosis and urine extravasation, which is a good examination method for early postoperative exclusion of ureteral injury.

　　4. CT examination:Due to the different locations and nature of the injury, CT findings may vary. Ureteral rupture caused by pelvic surgery often shows extravasation of contrast agent, and CT scanning shows high-density ascites.

　　5. Indocyanine green intravenous injection test:If ureteral injury is suspected during surgery, indocyanine green is injected intravenously, and blue urine will flow out from the ureteral fissure.

　　During or after surgery, cystoscopy should be performed, and indocyanine green (ICG) intravenous injection should be done. If there is no blue urine discharge from the ureteral orifice on the injured side, and the ureteral catheter is obstructed at the injury site, it often indicates ureteral obstruction.

　　6. Methylene blue test:By injecting methylene blue solution through a catheter, it is possible to differentiate between ureteral and bladder fistulas. If the fluid discharged from the bladder or vaginal wound remains clear, a bladder fistula can be ruled out.

　　7. Excretory urography and computed tomography (CT):All can show urine extravasation, leakage, or obstruction at the site of ureteral injury, and retrograde pyelography can show obstruction or extravasation of contrast agent.

　　8. Radionuclide renal imaging:It can show obstruction of the upper urinary tract on the ligated side.

　　1. Diet should be balanced and diverse. In addition to a balanced intake of rice, noodles, and杂粮, it is recommended to eat more green fresh vegetables, and often consume fish, lean meat, eggs, soy products, milk, garlic, onions, vinegar, and fruits. Eat less animal oil and sugar, cream, and avoid overeating and drinking strong alcohol, coffee, and strong tea.

　　2. During treatment, pay attention to rest more, avoid excessive activity, to avoid affecting the recovery process.

　　Treatment is given based on the time of diagnosis, the mechanism of injury, and the patient's general condition. If an immediate diagnosis can be made, emergency surgical repair is ideal. In unstable patients or postoperative ureteral injury, the first step is to insert a percutaneous nephrostomy tube to divert urine, and then perform imaging examinations to further determine the nature of the injury and plan appropriate surgical repair. Reconstruction includes ureteral reimplantation, primary ureteral anastomosis, anterior bladder flap, ileal grafting, and autografting. Treatment is given based on the time of diagnosis, the mechanism of injury, and the patient's general condition. If an immediate diagnosis can be made, emergency surgical repair is ideal. In unstable patients or postoperative ureteral injury, the first step is to insert a percutaneous nephrostomy tube to divert urine, and then perform imaging examinations to further determine the nature of the injury and plan appropriate surgical repair, including ureteral reimplantation, primary ureteral anastomosis, anterior bladder flap, ileal grafting, and autografting.

　　I. Treatment

　　The goal of treating ureteral injury is to restore normal urinary passage and protect the function of the affected kidney. First, the patient's overall condition should be judged, whether there is injury to other organs, and treatment should be given first; when complications such as respiratory and circulatory failure and hypovolemia occur, they should be corrected. The treatment principles are: 1. If ureteral injury is found during surgery and there is no contamination, primary repair surgery should be performed. 2. If the injury is >24h, it is advisable to perform temporary percutaneous nephrostomy first to drain the extravasated urine, and then perform repair surgery after 3 months. 3. For ureters that have been tied incorrectly, the tie site can be released; for ureters that have been cut or pierced, local repair surgery can be performed, and a ureteral stent can be placed for drainage. 4. The extent of ureteral injury

　　II. Prognosis

　　Early diagnosis and timely and correct surgical treatment have a good prognosis for ureteral injury. Delayed diagnosis leading to infection, hydronephrosis, abscess formation, and ureteral fistula formation has a poor prognosis.