We have reported on perioperative renal function preservation during off-clamp, non-renorrhaphy open partial nephrectomy within 3 months after surgery.
The advantage of the off-clamp technique in perioperative renal function preservation is controversial. Wen et al. have reported less decrease in renal function in off-clamp surgery compared to that in on-clamp surgery (weighted mean difference: 4.81 mL/min/1.73 m2; 95% confidence interval: 3.53–6.08; p < 0.00001) [9]. Meanwhile, several studies have failed to show the advantages of off-clamp surgery in eGFR preservation over clamping surgery in pneumoperitoneum settings [10–13].
AS for the advantage of renorrhaphy, the non-renorrhaphy technique failed to benefit the preservation of perioperative renal function for ≥ T1b renal tumors in open partial nephrectomy compared with the cold ischemia technique [14]. In this study, the renal function was analyzed at 4 and 6 months after surgery. However, studies comparing single-layered and double-layered renorrhaphy have shown the benefits of single-layered renorrhaphy in eGFR preservation [4, 15, 16]. In these analyses, eGFR was assessed between the date of discharge and 1 month postoperatively. Considering these findings, it is possible that omission of renorrhaphy preserves renal function during the early postoperative period.
The RENAL score correlates with perioperative reduction in renal function during on-clamp partial nephrectomy [17]. In this study, split renal function was measured using diethylene triamine penta-acetic acid scintigraphy, which showed a significant decrease in ipsilateral renal function 6 months after surgery, with no significant change thereafter [17].
There are limited data on perioperative renal function during combined off-clamp and non-renorrhaphy partial nephrectomy. We have recently reported the surgical results of off-clamp, non-renorrhaphy open partial nephrectomy for ≥ T1b renal tumors [8]. The perioperative eGFR preservation at 1 month and 3 months after surgery was 88.9% and 87.3%, respectively [8]. In laparoscopic or robotic surgeries, perioperative eGFR preservation was 96.9–100% for highly selected patients [18, 19]. In our study, the eGFR preservation at 5 days, 1 month, and 3 months after surgery was 95.3%, 91.0%, and 90.7%, respectively. We believe our report will add some knowledge on the chronological recovery of renal function after off-clamp, non-renorrhaphy partial nephrectomy.
Estimated blood loss was an early predictor of perioperative eGFR preservation, but was replaced by age at 3 months after surgery. Within 1 month after surgery, we assumed that damage of renal parenchyma by soft coagulation directly contributed to the decrease in the eGFR. Impairment of the potential for renal function recovery by age may affect eGFR preservation > 3 months after surgery [20].
This study has some limitations. First, the study was a retrospective study. Second, the postoperative eGFR was analyzed only within 3 months after surgery.
In conclusion, we have analyzed perioperative changes in renal function after off-clamp, non-renorrhaphy open partial nephrectomy until 3 months after surgery. The perioperative eGFR preservation rates of 95.3%, 91.0%, and 90.7% at 5 days, 1 month, and 3 months after surgery, respectively, reported in our study may be used as reference in the era of RAPN.