High Spontaneous Resolution Rates of Severe Primary Vesicoureteral Reflux and Minimal Development of New Renal Scars

PURPOSE: The previous reports regarding VUR resolution were not precise due to early frequent surgical intervention. We evaluated the spontaneous resolution (SR) rate and the incidence of new renal scars in primary VUR, focusing on severe reflux. METHODS: Medical records of 334 patients with primary VUR who were on medical prophylaxis without surgery for 1 to 9 years, were retrospectively reviewed. Medical prophylaxis was initiated with low-dose antibiotic prophylaxis or probiotics. Radioisotope cystourethrography was performed every 1 to 3 years until SR of reflux. New renal scar was evaluated with follow-up 99mTc DMSA renal scan. RESULTS: The SR rates decreased as VUR grades were getting higher (P=0.00). The overall and annual SR were 58.4% and 14.9%/yr in grade IV reflux and 37.5% and 9.3%/yr in grade V reflux. The median times of SR were 38 months in grade IV reflux and 66 months in grade V reflux. The probable SR rates in grade IV and V reflux were 7.8% and 8.9% in the 1st year, 46.0% and 30.8% in the 3rd year and 74.4% and 64.4% in the 5th year. The incidences of new renal scars between low to moderate reflux and severe reflux showed no significant difference (P=0.32). CONCLUSION: The SR rates of severe primary VUR were higher than previously reported and most new renal scars were focal and mild.

The Clinical Characteristics of Infantile Primary Vesicoureteral Reflux and Its Spontaneous Resolution Rate

PURPOSE: Childhood primary VUR is generally diagnosed after urinary tract infection, is more prevalent among girls and has a low spontaneous resolution rate in cases of severe VUR. The aim of the present study is to examine the age and gender-related characteristics and the spontaneous resolution rate of infantile primary VUR. METHODS: The medical records of 96 infants with primary VUR, diagnosed after their first UTI, were retrospectively reviewed(1995-2004). The clinical characteristics including gender, the degree of VUR and presence of renal scars were evaluated. The spontaneous resolution rate and contributing factors were also analyzed. RESULTS: Infantile primary VUR was more prevalent in males than females. The percentage of atrophic scarred kidney was significantly higher in males than females(17.2% vs 3.4%)(P<0.05). The cumulative spontaneous resolution rate in 3 years was very high(89.1%), and was not significantly different between gender and among VUR grades. But in the first year, the spontaneous resolution rate of severe refluxing ureters was significantly higher in males than in females(46.2% vs 7.1%)(P<0.05) and the spontaneous resolution rate of refluxing ureters with no scarred kidneys was significantly higher than those associated with atrophic scarred kidneys(76.6% vs 20%)(P<0.05). CONCLUSION: Infantile primary VUR was more prevalent among males and tends to be associated with atrophic scarred kidneys in male infants. The cumulative spontaneous resolution rate in 3 years was very high, even in high-grade VUR and associated atrophic scarred kidneys. In infantile primary VUR, surgery should be withheld even in infants with high-grade VUR with atrophic scarred kidneys.