New Delhi. A stone in the kidney passage of less than 5mm should not be treated as it will invariably pass in the next four weeks, as per the new kidney stone international guidelines, said Dr. K K Aggarwal, President, Heart Care Foundation of India.

A stone between 5 to 10 mm has only 20% chances of passing spontaneously. A stone of more than 10mm invariably require a non-medical intervention.

Dr. Aggarwal said that new avenues in stone management include a trial by drugs, which help in expulsion of the stone by relaxing the smooth muscle. The drugs used are Nifedipine (calcium channel blocker), alpha-blockers and steroids.

Uptil now it was thought that the best investigation for renal stone is intravenous pyelography. But now it has been prove beyond doubt that when a patient presents with kidney pain and a renal stone is suspected the undisputed investigation of choice is unenhanced CT scan of the abdomen. As per the guidelines, open removal of stones is no more recommended. Lithotripsy, PCNL and ureteroscopy have practically taken over from the open surgical procedures.

North India is considered a stone belt, with maximum cases of kidney stones in India.