Journal of Indian Association of Pediatric Surgeons
Journal of Indian Association of Pediatric Surgeons
                                                   Official journal of the Indian Association of Pediatric Surgeons                           
Year : 2019  |  Volume : 24  |  Issue : 2  |  Page : 154--155

Extrinsic vessel associated with ureteropelvic junction obstruction


Prema Menon, Katragadda Lakshmi Narasimha Rao 
 Department of Pediatric Surgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Correspondence Address:
Dr. Prema Menon
Department of Pediatric Surgery, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh - 160 012
India




How to cite this article:
Menon P, Narasimha Rao KL. Extrinsic vessel associated with ureteropelvic junction obstruction.J Indian Assoc Pediatr Surg 2019;24:154-155


How to cite this URL:
Menon P, Narasimha Rao KL. Extrinsic vessel associated with ureteropelvic junction obstruction. J Indian Assoc Pediatr Surg [serial online] 2019 [cited 2019 Jun 24 ];24:154-155
Available from: http://www.jiaps.com/text.asp?2019/24/2/154/253336


Full Text



Sir,

We read with interest the article by Gupta et al. on extrinsic vessels causing ureteropelvic junction obstruction (UPJO).[1] In this study, 18 (85.7%) of 21 patients had mild-to-moderate hydronephrosis. As mentioned in our previous study also, this finding as well as the presence of a predominant intrarenal pelvis is different from the more common intrinsic UPJO causing delay in diagnosis.[2]

However, our observations are not synchronous with the authors' comment that function was preserved in the majority. A differential renal function (DRF) of 30% and above has been taken as a cutoff for good function. Interestingly, a significant number of patients (38.1%) had a function below 30%.[1] Previous studies have used a cutoff of ≥35% or ≥40% DRF as good function.[3],[4] It would be interesting to know the mean DRF ± standard deviation of the group with >30% function and the number of patients with a DRF of 40% and above.

Our previous study showed the importance of the preoperative intravenous urogram (IVU) in predicting the possibility of a crossing vessel (CV) in UPJO. This study included patients from 2003 to 2013. Since then, between 2014 and 2017, we have operated upon another 20 patients aged 2–12 years (mean: 7.2 years) and a male-to-female ratio of 3:1 with a CV causing extrinsic UPJO. Based on IVU, we were able to successfully predict a CV in 15 of 19 patients who underwent this investigation [Figure 1], with the other 4 patients having very poor uptake/nonvisualized kidney. The IVU was compared between two age groups: Group 1 (2–5 years; mean: 4.4 years [n = 5]) and Group 2 (5–12 years; mean: 8.9 years [n = 10]). The renal pelvis was predominantly intrarenal and rounded/flat bottomed in all the patients (100%) in both the groups. In 3 of 10 patients in Group 2, the pelvis became rounded only after the administration of Lasix. The renal pelvis was found to be small in 3 (60%) and 7 (70%) patients in Groups 1 and 2, respectively; the calyces were found to be round and dilated in 5 (100%) and 8 (80%) patients in Groups 1 and 2, respectively. In those with very poor renal uptake on IVU, a percutaneous nephrostomy contrast study showed similar characteristic features.{Figure 1}

The affected side had a mean DRF of 25.6% (range: negligible to 52%). In 14 (70%) units, the DRF was below 35%. Five had DRF ≤10%. Preoperative ultrasound showed that 13 (65%) units had grossly thin parenchyma. Two patients had to be treated for hypertension preoperatively, an association we have observed in our earlier study also. All patients became asymptomatic after dismembered pyeloplasty with an increase in mean DRF to 30.3% (range: 10%–50%) with no nephrectomies.

Since the extrarenal pelvis is often not very dilated on ultrasonography (USG), these children tend to be kept on conservative management for a long time leading to a loss of function. Data from our recent experience (2014–2017) showed a DRF <35% in 70% units. In Gupta et al.'s series, 23.8% had DRF of 10%–30%, whereas 14.3% had DRF <10%. One of their patients underwent nephrectomy. While concerns are expressed on exposure to radiation with IVU, we feel that our data and that of Gupta et al. indicate the importance of early diagnosis of CV in children due to the real danger of loss of function if we rely only on ultrasound of the kidney, ureter, and bladder.

The assumption of preserved renal function cannot be derived from adult studies as the severity of illness may be different in the different age groups. The fact that our patients presented earlier in life indicates that they were symptomatic because of renal obstruction.

In our recent experience (2014–2017), 6 (30%) of 20 patients had associated intrinsic obstruction, which can also contribute to the loss of function. These data are missing from Gupta et al.'s paper although the authors speculate that this may have been a contributing factor to the loss of function.

We have on more than one occasion, noted a missed CV on patients referred for redo pyeloplasty. Endopyelotomy, if done for the same, can have disastrous consequences. Lower pole CV (LPCV) if ligated by a trainee/junior surgeon can lead to loss of the lower pole. Preoperative knowledge of the presence of LPCV thus helps in guiding the surgeon and is beneficial to the patient.

We would like to reiterate that there is a loss of renal function in children with extrinsic UPJO due to CV. The most common presentation in children is colicky abdominal pain. An USG performed for this, may show only mild or moderate hydronephrosis, delaying surgical intervention. There is a higher association with female gender compared to intrinsic UPJO. The IVU is highly diagnostic.[2]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Gupta A, Dhua A, Agarwala S, Bhatnagar V. Pelviureteric junction obstruction with crossing lower polar vessel: Indicators of preoperative diagnosis. J Indian Assoc Pediatr Surg 2018;23:123-6.
2Menon P, Rao KL, Sodhi KS, Bhattacharya A, Saxena AK, Mittal BR. Hydronephrosis: Comparison of extrinsic vessel versus intrinsic ureteropelvic junction obstruction groups and a plea against the vascular hitch procedure. J Pediatr Urol 2015;11:80.e1-6.
3Castagnetti M, Novara G, Beniamin F, Vezzú B, Rigamonti W, Artibani W. Scintigraphic renal function after unilateral pyeloplasty in children: A systematic review. BJU Int 2008;102:862-8.
4Capolicchio G, Leonard MP, Wong C, Jednak R, Brzezinski A, Salle JL. Prenatal diagnosis of hydronephrosis: Impact on renal function and its recovery after pyeloplasty. J Urol 1999;162:1029-32.