[Isotopic kidney investigations in staghorn lithiasis in the adult (author's transl)].

The authors report a study of 37 kidneys in 30 patients with staghorn calculi undergoing isotopic investigation of renal function by sequential scintigraphy and isotopic nephrogram by gamma-camera. 7 of the patients had bilateral staghorn calculi. Tracers used: Hippuran labelled with I131 and DPTA labelled with Technetium 99 m. 62% of kidneys poorly tolerated their staghorn calculus as shown by severe impairment of the isotopic nephrogram involving the uptake phase. Amongst the 20 cases of unilateral lithiasis, a nephrectomy was performed whenever the functional value was less than 20% normal (7 kidneys). Twelve stones were removed with conservation of the kidney. It should be noted that with renal function greater than 70% normal, the thickness of the renal parenchyma as assessed by IVU is never less by more than 1/2 cm that of the contralateral kidney. In the group, 11 patients underwent postoperative urography and scintigraphy with a mean follow up of 4 years. All extractions of calculi by pyelotomy with or without a small nephrotomy benefited initially impaired kidneys. By contrast, in 5 kidneys where a large nephrotomy was made, there was a gain in function in only one. 1 remained stationary and the others lost respectively 20, 30 and 100% of their function. Correlation was good with other methods of split renal function studies (IVU and renal arteriography). Of essential importance is the fact that the irradiation associated with these isotopic investigations is 20 to 50 times less than that of IVU. Isotopic investigation is thus a good method for the assessment of changes in renal function after surgery for staghorn calculus.