Comparison of hilar clamping and non-hilar clamping partial nephrectomy for tumours involving a solitary kidney.

OBJECTIVE

• To compare outcomes of hilar clamping and non-hilar clamping partial nephrectomy for tumours involving a solitary functional kidney.

PATIENTS AND METHODS

• Between 1990 and 2009, 104 partial nephrectomies, excluding bench and autotransplant procedures, were performed on solitary functional kidneys. • An institutional review board-approved retrospective review was performed analyzing patient demographics, operative data, complications, oncological outcomes and estimated glomerular filtration rate (GFR). • GFR was calculated using the abbreviated Modification of Diet in Renal Disease equation. • Preoperative GFR was compared to Early GFR (lowest measured GFR 7-100 days postoperatively) and to Late GFR (GFR 101-365 days postoperatively). • Multiple linear regression analysis was performed to assess covariates affecting Late GFR. • Kaplan-Meier estimator was utilized to compare renal cell carcinoma (RCC) specific survival and non-RCC-related survival.

RESULTS

• In total, 29 partial nephrectomies with hilar clamping and 75 partial nephrectomies without hilar clamping were performed in solitary kidneys. Median follow-up was 57 months. • There was no difference in tumour size, location and the number of tumours resected between the two groups. Mean ischaemia time for the clamping group was 25 min. • Some 97% of the clamping procedures were performed with cold ischaemia. • There was no difference in intra-operative estimated blood loss, transfusion requirement or length of hospital stay. • The complication rate and spectrum of complications were similar between the two groups. • The two groups had similar preoperative GFR and Early GFR. The non-clamping group had a significantly smaller percent decrease in Late GFR (11.8% vs 27.7%, P= 0.01) than the clamping group. • The non-clamping group was significantly more likely to have a less than 10% decrease in Late GFR compared to the clamping group (60.9% vs 17.7%, P= 0.002). • On multivariate analysis, only hilar clamping was significantly associated with decreased Late GFR (estimate 15.0, P= 0.02). • Surgical margin positivity rate was higher in the clamping group (21% vs 4%, P= 0.01); however, the local recurrence rate between the two groups was similar. • The clamping and non-clamping groups had similar 5-year RCC-specific survival and 5-year non-RCC-related survival.

CONCLUSIONS

• Partial nephrectomy without hilar clamping in solitary kidneys provides similar cancer control compared to partial nephrectomy with hilar clamping. • Partial nephrectomy without clamping was associated with superior preservation of Late GFR. • No difference was detected in GFR early after surgery, possibly indicating that there may be ongoing renal loss after hilar clamping.