Improved Adaptation of Laparoscopic Partial Nephrectomy based on the Evaluation of Renal Function Using 99mTc-MAG3 Renal Imaging

We evaluated renal function before and after laparoscopic partial nephrectomy by calculating differential renal function thru the use of renal scintigraphy with 99mtecnetium-mercaptoacetyltriglysine (99mTc-MAG3).

Differential renal function was assessed for 62 patients undergoing laparoscopic partial nephrectomy for renal tumors with renal scintigraphy before operation and six months post operation.

Mean operating time, ischemic time, blood loss and tumor diameter were 142 min, 27 min, 75 ml and 2.0 cm, respectively. The mean reduced rates of calculating glomerular filtration rate (cGFR) of a bilateral and the diseased-side kidney were 7.96% and 23.3%, respectively, and was statistical significant (p<0.001).

Meanwhile, the mean rate of increase of cGFR on the non-diseased-side kidney was 6.8%, which was significantly decreased (p=0.005). By univariate analysis, patients with a tumor of more than 2 cm in size and with clamping of the renal artery for over 30 minutes had decreased 6-month postoperative cGFR by more than 20%.

In multivariate analysis, tumor size was the most significant factor related to a decrease in cGFR. Patients with a tumor larger than 2 cm in size had a longer operation time (p=0.0005) and a higher amount of bleeding (p=0.0012).

In comparison, the six-month postoperative cGFR of patients less than 55 years-old had significantly increased cGFR over 20%.

Lower cGFR of the diseased-side kidney after partial nephrectomy was predicted by longer ischemic interval and tumor size. Age predicted increasing cGFR of the nondiseased side after partial nephrectomy. Currently, we are endeavoring to shorten ischemic time. Younger patients with renal tumors should adapt to laparoscopic partial nephrectomy.

Keywords: Laparoscopic nephrectomy, MAG3, Partial nephrectomy, Renal cell carcinoma, Renal scintigraphy.