In the past few decades, there have been controversies whether the ectopic blood vessels is the main cause of UPJO. Due to the development of minimally invasive urological techniques, a more comprehensive understanding has been proposed by urologists regarding the etiology heterotopic perirenal vessels. Although some experts believe that the CVs may not always exert pressure on the UPJ, the decrease in the success rate of endoscopic treatment due to heterotopic blood vessels and the success of the Hellström technique confirm the importance of the heterotopic blood vessels in UPJO surgery. Leavitt et al. reported that the CVs accounted for approximately 22.7% of 601 UPJO cases. Further, they summarized six different deplaning positions between the UPJ and CVs, of which the probability of the CVs compressing the UPJ from the posterior position was 7.4%[13]. These results are consistent with the data obtained in our study (Table 1).
Although routine transposition of CVs during laparoscopic AH plasty is the gold standard for treating UPJO patients with CVs, an increasing number of urologists are questioning the validity of this traditional method. Szydelko T and Ng CS reported that the traditional dorsal transposition of the vessel would not necessarily create a tension-free anastomosis, a better planing structure may be obtained with its cephalad translocation[14, 15]. Further, Janetschek G et al. claimed that dorsal displacement of the CVs may worsen the anatomic conditions[16]. In a multi-center study, Chiarenza SF et al. suggest that carefully selected patients with CVs could be treated with vascular surgery[17]. A systematic description of three types of patients according to the different locations of UPJ and ventral CVs were summarized by A. Schneider et al. They suggested that AH pyeloplasty should be performed when the CVs are present anterior to the dilated pelvis or the UPJ with intrinsic stenosis site, while vascular suspension should be performed when the vessels are present posterior to the UPJ, resulting in ureteral kinking[18].
Although the current procedure of transposing, fixing, and suspending the CVs is controversial, the consensus among experts is that after careful dissection during the operation, further selection is made on the basis of the etiology of the CVs, endogenous obstruction, laparoscopic approach, relationship with the surrounding tissues, such as the UPJ, and the potential for obstruction[12, 15, 19, 20]. In our study, the techniques were selected according to the anatomy between UPJ and CVs. Some experts believe that transposition facilitates anastomosis in the transperitoneal approach, and it can provide better anterior access to the renal pelvis and renal CVs[21, 22]. In contrast, we believe that the posterior approach can provide us with a clear understanding of whether the CVs exert pressure on the UPJ because the position of the CVs and UPJ is not affected during the surgery with the posterior approach. Moreover, we found that the degree of hydronephrosis for the dorsal CVs was relatively mild compared to that for the anterior CVs (Table 2). In the case of posteriorly located CVs, they can be suspended on the psoas muscle without affecting the subsequent operation (Fig. 2C, D).
As described previously, besides AH pyeloplasty, the tension-free renal pelvis and ureteral reanastomosis after the operation is an important aspect[12]. Zeltser IS et al. showed that CVs located within 5–6 mm of the ureteropelvic junction can cause a problem[23]. Boylu U et al. considered that transposition was performed when the anastomosis after mobilization was less than 1 cm from the CVs[12]. We suggest that the distance between the CVs and the new anastomosis should be at least 1 cm based on the changes in position during and after the operation. Therefore, according to the relationship between the new anastomosis and CVs after pyeloplasty, we have further divided treatment of the CVs into the following five individual procedures. When there is no pressure on the anastomotic site after pyeloplasty or transposition of CVs to the posterior side, we do not provide any further treatment. When the location of the CV is too close to the new anastomosis, we consider suspending the CV anterior to the pelvis or posterior to the psoas major muscle (Fig. 2A, B). If none of the above methods meet our requirements, we may consider transecting the vessel. Kelly cut the vessels using laparoscope in 2 cases with clinical improvement and without hypertension[24]. We had a similar case in this study, and the postoperative outcome was commendable during the follow-up. In conclusion, the final decision was made by the surgeon after visualization and tactile sensation of the new association between the renal pelvis, ureter, and CV in each individual.
The limitations of this study are the small sample size, the subjective judgment of intrinsic pathogeny, and the possibility of complex and rare vascular anatomic position. Further studies will be carried out to validate our classification through intraoperative opacification and postoperative pathological examination and confirm the intrinsic stenosis. A prospective and multicentric study will be conducted with increased sample size. A comprehensive evaluation of the relationships between blood vessels and UPJ according to the individual situation is necessary to provide the appropriate treatment plan.