Cooling Technique Promotes Kidney Stone Removal

A new study describes a minimally invasive surgery (MIS) technique that combines robotic surgery with renal hypothermia to remove large staghorn calculi.

Developed by researchers at Henry Ford Hospital (Detroit, MI, USA) and Muljibhai Patel Urological Hospital (MPUH; Gujarat, India), the new method, called robotic anatrophic nephrolithotomy (RANL), was devised to remove staghorn calculi that can be mortal if left untreated. The procedure is based on intracorporeal cooling and extraction (ICE), which passes a sterile ice slurry through special delivery syringes and a small surgical port to protect the kidney during its ischemic "down time.”


The procedure was performed for the first time on three patients with staghorn calculi (mean total stone volume 12,887.67 mm³) using a Gelpoint port for the ice slush insertion. Intracorporeal temperatures were lowered to less than 9 °C within 30 minutes of cold ischemia. Mean console and cold ischemia times were 167 and 56.7 minutes, respectively, and there were no complications. Two patients had residual fragments measuring 13 mm, and two 9 mm stones, respectively. The study was published ahead of print on July 16, 2013, in the Journal of Endourology.

“Removing large stones from the kidney requires a bloodless field and longer ischemic times than when removing kidney tumors,” said lead author Khurshid Ghani, MD, of the Vattikuti Urology Institute at Henry Ford Hospital. “This can now be achieved with the ICE procedure during robotic surgery. The hope is that all of the stone can be removed during a single operation.”

Staghorn calculi are branched struvite stones that occupy a large portion of the collecting system, typically filling the renal pelvis and branching into several or all of the calices. They are most frequently composed of mixtures of magnesium ammonium phosphate and/or calcium carbonate apatite. Over time, untreated staghorn calculi are likely to destroy the kidney and cause life-threatening sepsis. Complete removal of the stone is an important goal in order to eradicate any causative organisms, relieve obstruction, prevent further stone growth and any associated infection, and preserve kidney function.

Related Links:
Henry Ford Hospital
Muljibhai Patel Urological Hospital