Our study, including 40 cases of missed iatrogenic intraoperative ureteral injuries, showed that gynaecological surgery was responsible for 85% of those injuries, mainly during hysterectomies. Iatrogenic ureteral injury was diagnosed during the first month in most cases, and the symptoms were dominated by low back pain, pyelonephritis, and vaginal leakage of urine. Endoscopic treatment was sufficient in 12 out of 22 cases. Ureteral injury required surgical treatment in 24 cases, and ureteroneocystostomy was performed in 16 cases. Nephrectomy was performed in eight cases, representing 20% of ureteral injuries. Endoscopic treatment had a higher probability of succeeding in ureteral fistula when compared to ureteral stenosis, and the nephrectomy rate was higher in lately diagnosed intraoperative ureteral injuries.

In addition to the retrospective nature of the data collection, the main limitation of our study is the exclusion of a certain number of patients because of missing data concerning the intervention or the follow-up. Ureteral lesions diagnosed intraoperatively were not included because the purpose of our study was to show the morbidity of these lesions in case of postoperative diagnosis to emphasize the importance of prevention and immediate diagnosis in high-risk surgery.

The epidemiology of ureteral injuries has evolved considerably in recent decades [7]. Indeed, iatrogenic injuries are now the main cause of ureteral wounds (98%) [8]. The estimated frequency of intraoperative ureteral injuries during abdominopelvic surgery varies greatly depending on the series analysed [1]. However, the incidence of ureteral lesions was increased approximately fivefold in prospective studies if a search for a potential injury intraoperatively after intravenous injection of indigo carmine was performed [9]. In gynaecological surgery, the incidence of iatrogenic ureteral injuries ranges from 0.013 to 1.8% [10]. This surgical discipline alone accounts for 47–55% of all ureteral injuries reported in the literature. In our series, gynaecologic surgery was the cause of ureteral lesions in 80% of cases [10]. This frequency also depends on the type of surgery performed: Hysterectomy is the procedure most frequently responsible for these lesions, with a reported rate that ranges from 0.3 to 1.8% [6]. Whether the surgery is abdominal or vaginal, the ureter is always at risk [8]. Radical hysterectomies with lymphadenectomy (Wertheim type) are the greatest providers of ureteral injuries: 10 to 30% of cases [4]. In our study, hysterectomy for a benign condition was the most frequent cause, followed by the Wertheim procedure. Moreover, laparoscopic surgery does not spare this organ; In a Norwegian study over 11 years, the rate of ureteric injury after laparoscopic hysterectomy was 1% (33.4% of ureteric injuries after hysterectomy) [6]. However, the incidence of intraoperative ureteral injuries remains more frequent in open surgery than in laparoscopy [6], as demonstrated by our results, where laparoscopy was responsible for 15% of those injuries.

Besides, visceral surgery is responsible for 15 to 23% of ureteral injuries (15% in this study) [6]. Colorectal surgery, particularly abdominoperineal resection, and sigmoidectomy exposes the ureter to iatrogenic injury, especially during intestinal dissection. The risk of uretero-colic fistulisation is more frequent than uretero-intestinal fistulisation [11]. Vascular surgery accounts for 4 to 10% of ureteral lesions [10]. A few cases have also been reported after orthopaedic surgery (spine) [10]. We did not find any ureteral injury secondary to vascular or orthopaedic surgery.

Different types of iatrogenic ureteral injuries are identified: obstruction (by ischemia, ligation, or crushing) or fistulisation (in the vagina, uterus, and peritoneum, through the scar or the drainage system). The injury mechanisms found were ligation (wires or clips), sectioning, crushing, resection and denudation by dissection altering the vascularization [8]. In laparoscopy, coagulation injuries damaging the ureteral vascularization are the most common [12].

Ideally, iatrogenic ureteral injury is diagnosed intraoperatively and treated immediately. Unfortunately, 50–70% of ureteral injuries are not diagnosed intraoperatively [1, 12, 13]. Our study focused exclusively on postoperative diagnosed ureteral injuries, and the diagnosis was made in the first month after surgery in 75% of cases.

The most frequent diagnostic circumstances are low back pain and fever related to pyelonephritis in most cases or infected urinoma. Low back pain may be present depending on the nature of the injury and whether the ureter is occluded or has fistulated to the peritoneal cavity, retroperitoneal space, or to vagina in women [6].

The CT urography allows the diagnosis to be made. Urogram locates the injury by showing an arrest of the contrast material in case of obstruction or a leakage in case of fistula. In the latter case, the dilatation of the excretory cavities may be absent [14].

The treatment choice is based on the topography, extension, time between the onset of the intraoperative ureteral injury and diagnosis (early or late), mechanism, and patient comorbidities [4, 15]. Deferred surgery (three to six months after the initial lesion) to permit the resolve of inflammatory processes and the restoration of tissue integrity is the standard management of delayed diagnosis ureteral lesions. However, more recently, initial endourological treatment has been shown to substantially reduce morbidity, reduce re-operation rates and promote spontaneous recovery [16].

Thus, the endoscopic approach is often preferred as the first-line treatment. Retrograde ureteral catheterization represents, for several authors, the first initiative, as is the case in our centre. In case of failure, the percutaneous approach with anterograde catheterization of the excretory tract is used [16, 17]. However, antegrade upper tract urinary diversion can be proposed as a first-line procedure offering the possibility of an antegrade placement of a JJ stent if deemed feasible after opacification [8].

No consensus has been established on the duration of the JJ stent, but several authors suggested that the stent could be safely removed between two and six weeks [18]. In the literature, endourological treatment was successful in 33 to 64% of cases [16]. In this study, the success rate was 54.2%.

If endoscopic treatment is impossible or fails, surgical treatment becomes indispensable. Usually, a waiting period of 6 weeks to 3 months was suggested before reconstructive surgery. This period is necessary for inflammation, fibrosis, adhesions, tissue oedema, and anatomical distortions to disappear [18]. Other authors have reported comparable results for immediate post-diagnosis reconstruction versus delayed repair [18]. These results do not allow a definitive conclusion to be drawn, and the timing of ureter repair must be decided according to the patient and the surgeon’s habits [18]. In our centre, this delay was, on average, three months.

Anterograde pyelogram using a nephrostomy catheter is the reference imaging method to localize the level of the injury, and to adapt the surgical treatment. In the case of a functional kidney, the surgical treatment depends on the location of the ureteral injury.

Ureteroneocystostomy is preferred when the lesion is distal (< 3-5 cm) above the ureterovesical junction) and less than 2 cm [8]. Indeed, above these limits, a bladder elongation to allow tension-free reimplantation had to be associated using the vesico-psoas hitch technique or the Boari-tubularized bladder flap [8].

In case of small (2–3 cm) defects of the mid-ureter and upper ureter, a ureteroureterostomy can be performed, with the placement of a double-J catheter protecting the anastomosis [8].

In case of an extensive defect, a trans-ureterostomy (terminal-lateral anastomosis between the damaged and the healthy ureter) was a feasible option at the cost of risks of damage to the healthy ureter [10].

Finally, regardless of the level of injury, when the loss of substance is too great, ureteroileoplasty remains a reference technique of last resort, given its morbidity [19]. Renal auto transplantation may also be an option, requires an extensive discussion with the patient about the potential complications [20].