185 Vascular Hitch Procedure for Accessory Lower Pole Vessels

Introduction The gold standard procedure for pelvi-ureteric junction obstruction has been the Anderson-Hynes dismembered pyeloplasty; involving the repositioning of the ureter and ureteropelvic anastomosis. However, the Hellstroem 'Vascular Hitch Procedure’ dictates the superior translocation of the accessory vessel and its fixation to the anterior pelvic wall. The latter has an estimated success rate >90%. Method During 2016-2020, at Leicester Royal Infirmary, 16 operations occurred on paediatric patients with pelvi-ureteric junction obstruction. The dismembered pyeloplasty was performed on 5 patients, 9 patients underwent the vascular hitch procedure, and 2 patients are currently awaiting the latter operation. All patients had a pre-operative functional magnetic resonance urography (fMRU) to identify and localise the accessory lower pole vessel. Results The mean hospital stay for the vascular hitch procedure was 1.5 days (range=1-2) in comparison to 4 days (range=3-5) for the dismembered pyeloplasty. The follow-up period ranged from 6 months to 3 years. Overall, it was noted that the patients were asymptomatic, had markedly reduced hydronephrosis on imaging as well as stable renal function noted on the MAG 3 renogram scan. Conclusions The laparoscopic vascular hitch procedure appears to be the superior operation for the management of pelvi-uteric junction obstruction as the patients had notably reduced hospital stay lengths.

Detection of obstructive uropathy and assessment of differential renal function using two functional magnetic resonance urography tools

Summary Aim: After detection of obstructive uropathy (OU), the indication for or against surgery is primarily based on the differential renal function (DRF). This is to compare functional magnetic resonance urography (fMRU) with dynamic renal scintigraphy (DRS) to assess OU and DRF in infants and children. Patients, methods: Retrospective analysis in 30 patients (female: 16; male: 14; median age: 5.5 years [0.2-16.5]), divided into subgroup A (age: 0-2 years; n = 16) and B (> 2-17 years; n = 14). fMRU was assessed by measuring renal transit time (RTT) and volumetric DRF with CHOP fMRU tool (CT) and ImageJ MRU plug-in (IJ). OU detection by fMRU was compared with DRS (standard of reference) using areas under the curves (AUC) in ROC analyses. Concordant DRF was assumed if absolute deviation between fMRU and DRS was < 5 %. Results: DRS confirmed fixed OU in 4/31 kidneys (12.9 %) in subgroup A. AUC of CT was 0.94 compared with 0.93 by IJ. Subgroup B showed fixed OU in 1/21 kidneys (4.8 %) with AUCs of 0.98 each. RTT measured neither by CT nor by IJ in confirmed fixed OU was < 1200 s – resulting in negative predictive values of 1.0 each. In subgroup A, DRF was concordant in 81.3 % of the kidneys for CT and DRS compared with 75.0 % for IJ and DRS. In subgroup B, CT and DRS were concordant in 91.7 %, and IJ and DRS in 45.8 % of the kidneys. Conclusion: fMRU accurately excluded fixed OU in infants and children, independent from the software used for quantification. However, assessment of DRF with fMRU deviated from DRS especially in infants who may profit most from early intervention. Thus, fMRU cannot fully replace DRS as primary functional examination. If, for clinical reasons, fMRU is performed in first place and it cannot exclude fixed OU, it should be followed by DRS for validation and DRF quantification.