Study of Correlation between Intrarenal Pressure and Post-Operative Complications in Percutaneous Nephrolithotomy

Introduction: Even after constant advancement and miniaturization in percutaneous nephrolithotomy complications are evident. Stone burden, pre-operative microbiological status of urine, comorbidity, age, operative time, intra-operative level of sterility and antibiotic prophylaxis are commonly discussed risk factors for post-operative complications during percutaneous nephrolithotomy. Assessment of relationship between intra renal pelvic pressure and the complications was the aim of this study.

Materials and Methods: A prospective study was undertaken in patients undergoing percutaneous nephrolithotomy under fluoroscopic guidance during twelve months’ duration. The demographic characteristics, body mass index, stone characteristics (burden, density and number), rise in intrarenal pressure in relation to position of surgery, different energy sources used and size of tract, duration of operation and perioperative complications during percutaneous nephrolithotomy were recorded and the findings and outcome analyzed.

Results: Out of 125 patients, intrarenal pelvic pressure was found to be raised >30 mmHg in 72.8% (91 cases). Forty-one patients (32.8%), developed fever, found to be significantly associated with raised intrarenal pelvic pressure >30 mmHg, (P = 0.01). WBCs counts were significantly high among the raised intrarenal pelvic pressure group. Age of the patients, gender, body mass index and hospital stay were insignificant variables for development of fever in relation with rise in intrarenal pelvic pressure. Stone burden, prolonged duration of surgery, prone position of surgery and use of pneumatic lithotripsy were significant variables causing rise in intrarenal pelvic pressure.

Conclusion: Raised intrarenal pelvic pressure (> 30 mmHg) in association with increased stone burden, prolonged duration of surgery, prone position and pneumatic lithotripsy during percutaneous nephrolithotomy are significant risk factors for the development of post-operative complications mainly fever.