Classification of Staghorn Calculi

Partial staghorn calculi were defined as renal pelvic calculi extending into two calyceal groups

Complete staghorn stones were defined as renal pelvic calculi extending into all major calyceal groups, filling at least 80% of the collecting system.

But for stones between 501 and 1500 mm2 an overlap between partial and complete staghorn calculi commonly occurs.

The size of a concrement (stone burden) can be expressed in different ways. A notation of the largest diameter is the most common way of expressing size in the literature, i.e., the length of the stone as measured on the plain film. With knowledge of the length (l) and the width (w), an appropriate estimate of the stone surface area (SA) can be obtained for most stones (1):

SA = l x w x π x 0.25 mm2

For a quick estimate of the stone surface area, please refer to Table A1 (Appendix).

The surface area can also be measured using computerized systems and from CT scans, but these are not always easy procedures. With knowledge of the surface area, the stone volume can be calculated by the formula below (2):

Volume = 0.6 x SA mm3

The Stone Surface Area (Table A1)

THANK YOU FOR YOUR ATTENTION