Clinical Value Of The Ration Of The Pelvic Diameter To The Parenchymal Thickness (PD/PT) In Assessing Postoperative Hydronephrotic Kidney Following Pyeloplasty With Congenital Hydronephrosis In Children

Objective:To explore clinical value of anterioposterior pelvic diameter (APPD), parenchymal thickness (PT) and pelvic diameter/parenchymal thickness (PD/PT ratio) following pyeloplasty, and determine the usefulness of the parameter in assessing postoperative outcome.Methods:23nephrydrotic children (13males and10females.15cases on the left and8cases on the right) who underwent standard dismembered pyeloplasty were chosen in this study. The patients were collected from August2006to December2011in the afflliated hospital of Zunyi Medical College (median age3.5years, range from28days to13years). Anterioposterior pelvic diameter (APPD) and parenchymal thickness (PT) was measured by using Color Doppler Flow Image (CDFI), and then pelvis/cortex ratio [PD/PT=anterioposterior pelvic diameter (PD)/parenchymal thickness (PT)] was calculated. Grade of congenital hydronephrosis in23patients were divided into mild, moderate and severe groups according to Grignon standard (mild hydronephrosis in5cases, moderate hydronephrosis in8cases,10cases of severe hydronephrosis). Correlation between the degree of preoperative hydronephrosis and follow-up time was analyzed. Intravenous urography (IVU), retrograde renography, cystoscopy, ureteral catheterization retrograde angiography and radionuclide renal dynamic imaging were examined. The value of PD/PT was compared to glomerular filtration rate (GFR) checked by radionuclide renal dynamic imaging. The follow-up period was from3months to5years (mean time2.5years).Results:1. Diseased kidney’s PD/PT ratio of postoperative measurement was no significant difference between the preoperative mild hydronephrosis and moderate ones (P>0.05):The differences of PD/PT ratio comparing with moderate hydronephrosis and severe ones and with severe hydronephrosis and mild ones are statistical significance (P<0.05). PD/PT ratio of diseased kidney was positive correlation with varying degrees of preoperative hydronephrosis (r=0.457); the PD/PT ratio was gradually narrowed with the prolongation of postoperative follow-up time, and was negatively correlated with postoperative the length of follow-up time (r=-0.341).2. The diseased kidney GFR of postoperative measurements in the preoperative mild to moderate hydronephrosis was no significant difference (P>0.05); the ratio were statistically significant between severe hydronephrosis and light and moderate and severe ones(P<0.05).The diseased kidney GFR was negative correlation with varying degrees of preoperative hydronephrosis (r=-0.392, P<0.05); the GFR increased gradually with the prolongation of the postoperative follow-up time, and was positive correlation with follow-up period after surgery (r=0.583, P<0.01).3. The PD/PT ratio was negative correlation with GFR (r=-0.623).4. All cases of postoperative IVU examination were developed. Pyelographic time was almost simultaneous with between preoperative mild hydronephrosis and the normal ones. That development time of the normal kidney was5to10minutes less than the diseased ones of preoperative moderate hydronephrosis and15to55minutes less than severe ones. That development time is prolonged with the severity of preoperative hydronephrosis and reduced with the prolongation of follow-up period. Ureteropelvic junction in all cases was showed unobstruction by cystoscopy and ureteral catheterization retrograde angiography exmination.Conclusion:PD/PT ratio can be used as an important index for postoperative pediatric hydronephrosis. Measurement of PD/PT ratio is ease and can be used for repeated examation.