Determining the proper stent length to use in children: age plus 10

Double-J ureteral stents are used in children following various surgeries. The length of Double-J stent to use is often determined empirically. An accurate and easy to recall mathematical relationship between stent length and another parameter would be helpful to a urologist treating children. We determined whether such a relationship exists between appropriate Double-J stent length and the age of the child.

We reviewed the ages of and Double-J stent length used in all children in the last 5 years. Proper stent length was defined as a gentle curve of the distal coil in the bladder on direct vision and of the proximal coil in the renal pelvis on fluoroscopy or ultrasound. Data were stratified according to laterality and gender, and then regression analyses were performed between patient age and stent length.

There were 153 patients who were stented during this period. The surgeries for which a stent was used included ureteral reimplantation in 37 cases, renal surgery in 57 and stone disease in 59. Patient age was 2 months to 17.9 years. Regression analyses demonstrated consistent and reliable (r2) relationships between patient age and Double-J stent length irrespective of gender or laterality. The general relationship is defined by the formula, stent length = patient age in years + 10.

To our knowledge this is the first study evaluating the proper length of Double-J stent to use in children. We determined that simply adding 10 to patient age served as a reliable and accurate rule of thumb to determine Double-J stent length irrespective of gender or laterality.