EURURO Vol. 72 No. 2

Brief Correspondence

Excisional Precision Matters: Understanding the Influence of

Excisional Volume Loss on Renal Function After Partial

Nephrectomy

Julien Dagenais, Matthew J. Maurice, Pascal Mouracade, Onder Kara, Ercan Malkoc,

Jihad H. Kaouk

Glickman Urological & Kidney Institute, Department of Urology, Cleveland Clinic

[3_TD$DIFF]

, Cleveland, OH, USA

A central tenet of partial nephrectomy (PN) is to optimize

preservation of functioning nephrons. Nephron injury may

arise from factors including prolonged warm ischemia time,

surgical excision of benign parenchyma (excisional volume

loss, EVL), and iatrogenic injury from reconstruction

[1] .

While the effect of ischemia time is thought to be

recoverable

[2] ,

the precision of surgical excision

[3]

and

reconstruction

[4]

has been shown to contribute to long-

term renal dysfunction. Prior studies have attributed a

generic 5 mm loss of peritumoral parenchyma to excision

and reconstruction when calculating the effect of PN-

induced volume loss on renal function

[5]

. However,

defining the impact of surgical precision on renal function

requires a better understanding of the explicit influence of

E U R O P E A N U R O L O G Y 7 2 ( 2 0 1 7 ) 1 6 8 – 1 7 0

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Article info

Article history:

Accepted February 3, 2017

Associate Editor:

Giacomo Novara

Keywords:

Partial nephrectomy

Renal function

GFR preservation

Chronic kidney disease

Excisional volume loss

Surgical precision

Robotic surgery

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Abstract

Renal function after partial nephrectomy (PN) may depend on modifiable factors

including ischemia time, excision of healthy parenchyma (excisional volume loss,

EVL), and reconstructive methods. We retrospectively reviewed our institutional robotic

PN database to identify the predictors of glomerular filtration rate (GFR) preservation

(GFR-P) at 3–12 mo postoperatively, during which GFR decline plateaus. Baseline

clinical, sociodemographic, and radiologic characteristics were captured. Univariate

and multivariate (MV) linear regression analyses were performed and marginal effects

were employed to examine the relative effect of EVL on renal function. A total of

647 patients who underwent robotic PN had GFR data at a median follow-up of 6 mo. On

MV models, EVL was significantly correlated with GFR-P following log transformation

(

= 0.001). Each doubling of EVL caused a 1.5% decrease in GFR-P. Ischemia time and

tumor complexity were not significantly associated with GFR-P. In summary, GFR-P after

PN appears to be significantly associated with the excised volume of benign parenchy-

ma.

Patient summary:

At a high-volume tertiary care center, we investigated the impact of

surgical factors on kidney function after kidney cancer surgery. We found that the

surgical precision with which the tumor is excised significantly impacts kidney function

at 3–12 mo after surgery.

* Corresponding author. Department of Urology, Cleveland Clinic Foundation, 9500 Euclid Ave.,

Q10-1, Cleveland, OH 44195, USA. Tel. +1 216-444-2976; Fax: +1 216-636-4492.

E-mail address:

kaoukj@ccf.org

(J.H. Kaouk).

http://dx.doi.org/10.1016/j.eururo.2017.02.004

0302-2838/