Objective : To compare the changes in renal function after surgery between standard and modified anatrophic nephrolithotomy using the technetium 99m-DTPA renal scan in patients with complex staghorn calculi.
Material and Method : From July 2001 to March 2002, standard anatrophic nephrolithotomy (sANL) was performed in 7 patients with complex staghorn calculi and modified anatrophic nephrolithotomy (mANL) was performed in another group of 8 patients with the same condition. Preoperative and postoperative renal function were assessed by technetium 99m-DTPA renal scan.
Results : Mean patient age was 41 years in the sANL group and 45 years in the mANL group. Male to female ratio was 4:3 in the sANL group and 5:3 in the mANL group. Median operative time was 205 minutes in the sANL group compare with 180 minutes in the mANL group (P = 0.03). Median estimated blood loss was 300 ml. in the sANL group and 275 ml. in the mANL group (P = 0.17). Median percent reduction of GFR on the operated kidney was 9.13 (-30.03 to -3.15) in the sANL group and 27.25 (-41.81 to -1.55) in the mANL group (P = 0.13). Residual small stone was seen in one patient of the sANL group and ESWL was performed for stone fragmentation. There were no serious short-term complications.
Conclusion : The average operative time of sANL was longer than mANL however, sANL preserved more renal function than mANL. This study suggested that sANL should be the procedure of choice in patients who have compromised renal function.

Keywords : Anatrophic nephrolithotomy, Staghorn calculi, Renal scan