Pelviureteric Junction Obstruction with Crossing Lower Polar Vessel: Indicators of Preoperative Diagnosis

A crossing lower polar vessel (CLPV) is found in 11%-20% of children of pelviureteric junction obstruction (PUJO). Preoperative imaging (Doppler or magnetic resonance angiography (MRA)) may help but does not form a part of routine diagnostic workup. An attempt has been made here to evaluate clinical and imaging features (ultrasound and renal dynamic scan [RDS]) in children of PUJO with CLPV and define variables that could provide a diagnostic clue to its presence.

Records of children having PUJO with CLPV over 10 years (2006-2015) were reviewed retrospectively. Their demographic profile, clinical presentation, imaging features, management, and outcomes were evaluated.

Of 372 children with PUJO, 21 (5.6%) had a CLPV. Median age at presentation was 7 years (range 4 months-11 years). Presenting features included pain (66.6%), urinary tract infection (14.3%), antenatally diagnosed fetal hydronephrosis (14.3%) and lump (4.8%). All had an obstructive drainage on RDS and mean split renal function (SRF) of the affected kidney was 32.5% ± 15.65%. The majority had mild-moderate hydronephrosis with intrarenal pelvis. None of the ultrasound images suggested the presence of a CLPV. Diagnosis of a CLPV was made intraoperatively in all. Dismembered pyeloplasty anterior to the vessel was done in the majority (80.9%). Mean SRF on postoperative RDS improved to 36.6% ±17.76% with nonobstructive drainage. All were asymptomatic at a mean follow-up of 34.5 ± 17.5 months (range 2-56 months).

Pain is the predominant presenting feature in these patients who present at an older age. Despite older age at presentation, these patients have well-preserved renal function and mild hydronephrosis. No specific RDS or ultrasound findings can predict the presence of a CLPV. As the incidence of CLPV is <10% and management is essentially same as PUJO with intrinsic obstruction, preoperative Doppler or MRA are extraneous.