Urolithiasis is a global disease with a prevalence rate of about 12% in Indian population and     out of which 50% may end up with loss of renal functions. PCNL (Percutaneous nephrolithotomy) stands as a gold standard surgical treatment for renal calculus disease. It has gradually replaced conventional open surgery for the removal of any size renal stone, specially large and complex one.

Since its first description by Fernstrom and Johansson in 1976, PCNL has traditionally been done with the patient prone, combining a high success rate and acceptable low morbidity.

The prone position has certain advantages like wide field of working area, easiness to puncture the calyx, shorter track length, ease of tract dilation, ease to do multiple punctures etc.But is associated with many problems like circulatory and ventilatory compromise because of compression on the chest especially in the obese patient; cervical spine injuries, tracheal compression and ocular injury during turning the patient; more fluid because of antigravity drainage of fluid.

Concurrent RIRS (Retrograde intrarenal surgery) is difficult in prone position. So there was a hunt in search of a new position which can ameliorate the disadvantages of traditional prone position.First original supine position was described by Valdivia et al. In this position the direction of the tract is downward and thus preserves a low pressure in the renal pelvis, and thereby reduces the risk of fluid absorption and allows spontaneous clearance/washout of fragments by gravity directed flow of fluid.The main limitation of this position is that the flank is not fully exposed, which makes initial puncture more difficult.

In 2007 The Galdakao-modified supine Valdivia position was described by Ibarluzea et al. for supine PCNL.

The aim is to compare the surgical outcomes between prone and supine PCNL.

This study will be done in patients who will be undergoing PCNL in urology department at RIMSH, Imphal, Manipur.

Study variables will include  age, gender,BMI,post operative haemoglobin drop,need for blood transfusion,mean operative time, number of patients developing complications,mean hospital stay,need for relook PCNL and stone free rate.

Patient will be evaluated with history, physical examination, urine analysis, urine culture and sensitivity, complete blood count, renal function tests, X-ray KUB, USG KUB, and Plain and contrast enhanced computed tomography / IVP.It is a convenience  non-probability sampling method where sample is collected from a group of people easy to reach or contact.After that patient who will be undergoing PCNL will be divided into two groups (Group A& Group B) which will be dicided by the cornerned operating surgeon.. Group A will undergo prone PCNL and Group B will undergo supine PCNL after obtaining anesthetic fitness for the procedure.

P-value <0.05 will be taken as statistically significant.