12.1
Generalities
Iatrogenic ureteral lesions can occur as a complication of abdominal surgical procedures, but in most cases they are due to pelvic or retroperitoneal interventions.
The incidence of iatrogenic ureteral injuries varies between 0.5% and 30% ( ). Recent data indicate a decrease in their frequency to 0.1–2.5% ( ). Ureteral lesions can be the result of multiple mechanisms:
- •
ligature
- •
elongation
- •
dilaceration
- •
devascularization
- •
avulsion
The widespread use of ureteroscopic and laparoscopic interventions has led to an increase in the incidence of secondary ureteral injuries ( ).
Iatrogenic ureteral injuries represent approximately 75% of all ureteral trauma ( ), the most important etiological factors being represented by:
- •
gynecological surgical interventions
- •
general surgery interventions
- •
urological interventions
The same author estimates a frequency of iatrogenic ureteral lesions after gynecological procedures of 1.6:1000. A relatively similar incidence (1.2:1000) was also described by . Regarding the location of the injuries, the pelvic ureter is most frequently affected (74%), followed by the middle ureter (13%) and the upper ureter (13%).
The most important published data regarding the etiology of iatrogenic ureteral injuries is summarized in Table 12.1 .
| Author | Number of cases | Etiology depending on the types of surgical procedures | |||
|---|---|---|---|---|---|
| Gynecological (%) | General (%) | Vascular (%) | Urological (%) | ||
| 165 | 34 | 17 | 7 | 42 | |
| 39 | 84 | 3 | 8 | 5 | |
| 32 | 63 | 7 | 30 | ||
| 34 | 47 | 23 | 10 | 20 | |
| 340 | 73 | 14 | 13 | ||
The incidence of ureteral lesions after laparoscopic surgery varies between 1% and 2% ( ). Laparoscopic hysterectomy is the intervention that causes most iatrogenic injuries, especially in case of the extensive use of electrocoagulation.
12.2
Classification
Ureteroscopic procedures generally cause minor mucosal injuries or minimal ureteral perforations ( ). These were described in detail in a previous chapter.
The use of small caliber instruments, as well as the more and more frequent use of flexible ureteroscopes, has led to a decrease in the incidence of these injuries ( ).
The American Association for the Surgery of Trauma classifies ureteral injuries into five grades ( Table 12.2 ).
| Grade | Characteristics |
|---|---|
| I | Hematoma |
| II | Transection <50% of the circumference |
| III | Transection >50% of the circumference |
| IV | Complete transection with <2 cm devascularization |
| V | Complete transection with >2 cm devascularization |
Although this classification is not used in practice, it is important for comparing the results from different published studies.
The classification most often used in practice is based on the mechanism involved.
12.2.1
Ureteral Ligature
Ureteral injuries occurring during vaginal surgical interventions are generally secondary to an accidental ligature and are usually detected after the procedure ( ). Most of them are the result of the failure to identify the ureter and occur during the hemostasis maneuvers ( ). Some authors recommend intravenous injection of indigo carmine and a cystoscopic control after interventions in the genital area. The absence of evacuation of dye through a ureteral orifice may allow the early diagnosis of an accidental ureteral ligature ( ).
12.2.2
Ureteral Crushing
The use of surgical clamps for hemostasis may determine ureteral crushing with significant injuries. This generally occurs during an attempt to stop the bleeding. In these cases, if the lesion is recognized during the intervention, the ureteral adventitia must be carefully examined because in many cases the ischemic lesions are important and can become evident only after several days. The severity of ureteral damage depends on the size of the clamp, on the moment when the clamp was applied, and on the mass of the crushed tissue. Placement of a JJ catheter is sufficient for minor lesions, while important injuries may require segmental ureteral resection.
12.2.3
Ureteral Devascularization
In general, lesions with ureteral devascularization are recognized late, when they are complicated by fistulas or ureteral strictures ( ). When ureteral thermal injuries or extensive ureteral skeletonization are identified during the intervention (possibly affecting viability), excision of the affected segment is recommended. Viability is difficult to assess in most cases. In case of any doubts, it is recommended to place a ureteral endoprosthesis.
12.2.4
Partial or Complete Ureteral Transection
Most partial transections occurring during surgical interventions can be treated by primary suture and internal drainage with a JJ catheter. If more than half of the ureter’s diameter is affected, some authors recommend segmental ureteral resection.
12.2.1
Ureteral Ligature
Ureteral injuries occurring during vaginal surgical interventions are generally secondary to an accidental ligature and are usually detected after the procedure ( ). Most of them are the result of the failure to identify the ureter and occur during the hemostasis maneuvers ( ). Some authors recommend intravenous injection of indigo carmine and a cystoscopic control after interventions in the genital area. The absence of evacuation of dye through a ureteral orifice may allow the early diagnosis of an accidental ureteral ligature ( ).
12.2.2
Ureteral Crushing
The use of surgical clamps for hemostasis may determine ureteral crushing with significant injuries. This generally occurs during an attempt to stop the bleeding. In these cases, if the lesion is recognized during the intervention, the ureteral adventitia must be carefully examined because in many cases the ischemic lesions are important and can become evident only after several days. The severity of ureteral damage depends on the size of the clamp, on the moment when the clamp was applied, and on the mass of the crushed tissue. Placement of a JJ catheter is sufficient for minor lesions, while important injuries may require segmental ureteral resection.
12.2.3
Ureteral Devascularization
In general, lesions with ureteral devascularization are recognized late, when they are complicated by fistulas or ureteral strictures ( ). When ureteral thermal injuries or extensive ureteral skeletonization are identified during the intervention (possibly affecting viability), excision of the affected segment is recommended. Viability is difficult to assess in most cases. In case of any doubts, it is recommended to place a ureteral endoprosthesis.
12.3
Diagnosis
Intraoperative direct visualization of the lesion represents the ideal diagnostic method. Most authors insist on the importance of early diagnosis (ideally during the intervention) of iatrogenic lesions. Unfortunately, only 20–30% of iatrogenic ureteral lesions are diagnosed during surgery, most of the time the diagnosis being established late, sometimes due to the secondary complications (urinomas, stenoses, fistulas).
The diagnosis is suggested by the postoperative occurrence, usually after 5–7 days, of signs and symptoms of unilateral ureteral obstruction: lumbar pains, oliguria or anuria (in bilateral injuries), fever, increase in azotate retention values, hematuria, uretero-vaginal fistula. The injury may be discovered accidentally in some cases. Imaging diagnosis is very important. Thus, abdominal ultrasonography may reveal dilation of the pyelocaliceal system and of the proximal ureter in case of ureteral ligature or of a stenosis developed late after the intervention. Doppler ultrasonography can detect the absence of ureteral flow on the affected side. Intravenous urography allows the visualization of the ureteral obstruction or the leakage of the contrast agent. Computed tomography is required in cases with an uncertain diagnosis. Retrograde pyelography ( Fig. 12.1 ) represents the “gold-standard” investigation for the diagnosis of iatrogenic injuries.
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