Evaluation of Object-Space Occlusion Culling with Occluder Fusion

In a retrospective analysis we studied the case histories of 31 children who had been seen in our department for investigation of pelvic ectopic kidney between January 1994 and June 2005. The evaluation of each involved the medical history, ultrasound examination, VCUG, and DMSA scan or MAG3 diuresis renogram. Of the 31 children, 21 (67.7%) had initially been referred to our department for further investigation and clarification because renal agenesis was suspected. In the remaining 10 (32.3%) children the pelvic kidney was an incidental finding observed during investigation of various other conditions. Overall, 7 (22.6%) of the 31 were symptomatic (recurrent urinary tract infections, abdominal pain, hypertension, hydronephrosis), while 77.4% (24/31) were completely free of symptoms at the time of follow-up. Ultrasound revealed that the ectopic kidney was on the left in 64.5% (20/31) of these cases. Nuclear scans performed both at the time of the initial diagnosis and at follow-up were available for 11 of the 31 children and showed a mild improvement of the partial function of the pelvic kidney, from a mean of 25.6% to a mean of 34.6%. In conclusion, whenever renal agenesis is suspected on ultrasonographic examination, the investigator should first consider renal ectopia; ultrasound examination with the bladder full is the definitive diagnostic procedure. For asymptomatic cases we recommend regular ultrasound monitoring of the kidney -- at first every 6 months and later once a year. In cases with complex anatomy MRI is a suitable method for further diagnostic work-up.