Comparison of hilar clamping and non‐hilar clamping partial nephrectomy for tumours involving a solitary kidney
Authors: Wszolek Matthew F. , Kenney Patrick A. , Lee Yoojin , Libertino John A. 
Published: November 2010

Study Type – Therapy (case series)

Level of Evidence 4

What’s known on the subject? and What does the study add?

It has been long recognized that ischemic injury to the kidney occurs when the blood supply to the kidney is interrupted by clamping of the renal artery (warm and cold ischemia). We developed a new technique of non‐clamping, non‐ischemic partial nephrectomy with this in mind. This article looks at the results of clamping vs non‐clamping partial nephrectomies in solitary kidneys, where the impact of ischemic injury is most accurately reflected. The technique of non‐ischemic partial nephrectomy accounts for 33% better preservation of renal function, when compared to ischemic partial nephrectomy. This new technique should be used in patients with a solitary kidney, patients with bilateral tumours, and patients with already impaired renal function.

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.