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Novel method expected to decrease loss in kidney function after partial nephrectomy


Researchers at Indiana University School of Medicine have discovered a modifiable factor, in robot-assisted partial nephrectomy, which could potentially decrease the loss in kidney function and post-operative complications. In a study published in the Journal of Endourology, it was found that omitting cortical renorrhaphy resulted in decreased renal volume loss and post-operative bleeding.

Robot-assisted partial nephrectomy is a minimally invasive technique to remove small masses or tumors in the kidney, while preserving the remainder of the kidney and renal function. Studies have estimated an approximate loss of 10 percent overall renal function after partial nephrectomy, along with a loss of 15 percent of the volume in the operated kidney. While renal volume is an important factor affecting renal function, experts have concluded that this loss is not modifiable. However, investigators in this study have challenged this inference. The assumption that volume loss is due to removal of tumors and not reconstruction hasn’t been tested.

“If we are removing non-functional tissue then why is there a loss in renal volume and function? We expect that by omitting one particular step during surgery, we will be able to improve renal volume loss and function,” said Clinton Bahler, MD, principal investigator and assistant professor of urology at IU School of Medicine.

Typically, in a minimally invasive partial nephrectomy, removal of the tumor is followed by base-layer suture to close openings in vessels and the collecting system. Next, the outer layer of the kidney is closed in a cortical renorrhaphy.

Dr. Bahler and his team of researchers have suggested the omission of the cortical renorrhaphy – suturing the cortex after a base-layer suture. It is widely believed that this step in surgery is needed to prevent urine leaks and post-operative bleeding, but never tested.

The researchers at IU School of Medicine challenged this assumption and suggested that omitting this step could be protective against postoperative bleeding. They assessed the safety of omitting cortical renorrhaphy during robot-assisted partial nephrectomy and measured preliminary functional outcomes. No urine leaks and post-operative bleeding was found in the 15 surgeries performed with omission of cortical renorrhaphy. The percent of renal volume loss was also improved.

“The generalizability of the study is limited, and its retrospective and non-randomized nature makes it vulnerable to bias,” Dr. Bahler said. “To address these limitations, we have a clinical trial currently open for enrollment, to evaluate the impact of reconstruction on complications and renal function.”

The trial is currently enrolling patients over 18 years of age with a renal mass who are considering partial nephrectomy.

If interested, please contact Courtney Dhondt with the Department of Urology research office at (317) 274-1791 or Dr. Bahler at More information can be found on the clinical trials registry.

The views expressed in this content represent the perspective and opinions of the author and may or may not represent the position of Indiana University School of Medicine.

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