Regional hypothermia in renal surgery for severe lithiasis

An active approach to severe renal lithiasis is advocated, though operative procedures often require interruption of the blood supply. Te evaluate the effect of ischemia on the kidney the literature has been searched and we have reached the following conclusions. A warm ischemic time of more than 20 minutes causes a brief and transitory reduction in renal function. If ischemia exceeds 30-40 minutes many kidneys will not regain their previous function. If the kidney's temperature is lowered to about 15 degrees C, ischemia can be tolerated for up to 12 hours. A priori these time limits applicable to normal kidneys are to broad for use in diseased kidneys. Cooling of the kidney can be achieved by either perfusion-cooling or by external parenchymatous cooling. We describe a method using the latter system for stone removal in 14 patients with staghorn calculi or multiple stones. Preoperatively 9 patients (64%) had persistent urinary tract infection, whereas infection persisted in only 2 patients following the operation (14%). Complete stone removal was achieved in 13 patients (93%). Renal function evaluated by creatinine clearance and renography generally improved following operation. There were no deaths, but in 9 patients severe complications were seen (transient oliguria and septicemia). At follow-up investigation 1.5 years after operation renewed stone formation was found in 1 patient, while the incidence of urinary tract infection had increased to 3 patients (21%). It is concluded that extensive surgery for stone removal with the use of external parenchymatous cooling is worthwhile and promising in patients with staghorn calculi or multiple stones in the kidneys.