Has Sliding-Clip Renorrhaphy Eliminated the Need for Collecting System Repair During Robot-Assisted Partial Nephrectomy?

Abstract

Objective:

We evaluated whether single-layer renorrhaphy (SLR) without collecting system (CS) closure is sufficient following robot-assisted partial nephrectomy (RAPN).

Patients and Methods:

One hundred fifty consecutive patients underwent RAPN by a single surgeon and were prospectively labeled with regard to CS entry during surgery. Patients with CS entry were subdivided into two groups: those with classical renorrhaphy (CR) (i.e., two-layer repair) and those with SLR (i.e., without CS repair). Perioperative variables and outcomes were compared between CR and SLR groups.

Results:

Ninety patients had CS entry during RAPN. Of these 90 patients, 64 had CR, and 26 had SLR, with mean ages of 62 and 59 years (p = 0.22), tumor sizes of 3.4 and 3.3 cm (p = 0.61), Mayo Adhesive Probability scores of 1.8 and 1.8 (p = 0.95), and radius, exophytic/endophytic, nearness to CS, and laterality scores of 8.5 and 8.0 (p = 0.16), respectively. Mean warm ischemia times (WITs) were 19.6 and 17.3 minutes (p = 0.04), hospital stays of 3.0 and 2.8 days (p = 0.62), and drain times of 2.9 and 2.7 days (p = 0.65), for the CR and SLR groups, respectively. Using the Clavien-Dindo classification, there were a total of six grade III or higher complications, with no difference between the CR and SLR subgroups (p = 1.0). Renal function using creatinine or glomerular filtration rate as surrogates showed no difference between groups preoperatively or up until 2 years postoperatively.

Conclusions:

Omitting CS repair during RAPN with SLR decreases WIT without altering complications, hospital stay, or drain time. Long-term renal function was not associated with CS repair.

Introduction

The introduction of robotic technology has equipped urologists with the tools necessary to treat an increased number of small renal masses with minimally invasive partial nephrectomy.^1
–3 Technical modifications to robot-assisted partial nephrectomy (RAPN) have improved outcomes in terms of operative morbidity and postoperative renal functional outcomes.¹

Many surgeons clamp the renal vasculature to maintain a bloodless field to optimize complete tumor excision and renorrhaphy. The duration of the ensuing warm ischemia time (WIT), especially if prolonged, likely impacts postoperative renal functional outcomes.^4,5 Traditional renorrhaphy techniques include collecting system (CS) closure followed by cortical renorrhaphy. The introduction of the sliding-clip renorrhaphy technique provided a rapid hemostatic technique for completing cortical renorrhaphy following renal tumor excision.⁶ Recently, authors have advocated for eliminating formal CS closure to decrease WIT without increasing pathologic urine leaks.⁷ Our hypothesis was that the sliding-clip cortical renorrhaphy provides a tight closure that may possibly eliminate the need for formal CS closure following RAPN. The primary aim of the study was to assess the safety and efficacy of eliminating formal CS closure following RAPN where CS violation had occurred. The secondary aim of the study was to evaluate whether eliminating formal CS closure improved WIT and possibly improved renal functional outcomes.

Patients and Methods

Following Institutional Review Board approval, a prospectively compiled single-surgeon RAPN database was reviewed. All patients who underwent RAPN and who had CS entry were included in this analysis.

Measurements and data collection

Patient demographics, including age and body mass index (BMI), American Society of Anesthesiologists (ASA), and Mayo Adhesive Probability (MAP) score⁸ were collected. Tumor characteristics, including tumor radius, exophytic/endophytic, nearness to CS, and laterality (RENAL) score,⁹ were collected. Operative variables such as operative time, WIT, estimated blood loss (EBL), and CS entry were recorded following each case. Length of hospital stay and postoperative complications were recorded utilizing the Clavien-Dindo classification system.¹⁰ Surgical margin status and final pathology were noted as well.

Renal function was estimated using serum creatinine. It was assessed at several time points: preoperative and 1 day, 1 month, 6 months, 1 year, and 2 years postoperatively. Glomerular filtration rate (GFR) was calculated using the Modification of Diet in Renal Disease GFR equation.¹¹

Surgical technique

RAPN was performed transperitoneally using the da Vinci Si robotic system (Intuitive Surgical Corporation, Sunnyvale, CA) as has been outlined in previous studies.¹² In short, intraoperative ultrasonography was routinely used for identification of tumor margins and approximation of tumor depth before hilar clamping with bulldog clamps. Tumor excision was then performed athermally using cold scissors.

When CS entry was noted intraoperatively by the surgeon, renorrhaphy technique was variable and was completed either with classical renorrhaphy (CR) or single-layer renorrhaphy (SLR). CR utilized two layers, closing the CS first with running 2-0 polyglactin sutures. Cortical renorrhaphy was subsequently performed using the well-described sliding-clip technique.⁶ SLR only consisted of one layer of closure. CS repair was omitted. The renorrhaphy site was routinely observed for 5 minutes with decreased intraperitoneal insufflation. Hemostatic agents were used when necessary.

Finally, a 19F, round full-fluted drain was placed in the perinephric bed and set to low suction using a 100 mL silicone bulb evacuator before abdominal closure. Drain creatinine was routinely obtained on postoperative day 1 with subsequent removal as long as drain creatinine was not significantly increased compared to serum creatinine. An indwelling urethral catheter was left in overnight and removed on the morning of postoperative day 1.

Data analysis

Statistical analyses were performed using SAS (v 9.4; SAS Institute, Inc., Cary, NC). The unpaired t-test was used to compare continuous variables. The χ ² test and Fischer exact test were used to compare categorical variables. Results were only considered significant if the p-value was <0.05.

Results

A total of 150 consecutive patients underwent RAPN between February 15, 2008 and April 7, 2015. Ninety patients had CS entry at the time of surgery. Of these, 64 patients had a CS repair performed, and 26 patients had CS repair omitted. Table 1 shows patient, tumor, and perioperative variables of all patients who underwent RAPN and those who had CS entry at the time of surgery.

Table 1.

Patient, Tumor, and Perioperative Variables for All Robot-Assisted Partial Nephrectomy and Those Who Had Collecting System Entry During Robot-Assisted Partial Nephrectomy

Variable	All RAPN	RAPN with CS entry
No. of patients	150	90
Age (years)	61.3 (22–83)	61.1 (22–83)
Sex
Male	92	50
Female	58	40
BMI (kg/m²)	29.6 (18.7–60.6)	30.4 (18.7–60.6)
ASA score	2.7 (2–4)	2.8 (2–4)
Preoperative Cr (mg/dL)	1.0 (0.5–3.8)	1.0 (0.5–2.5)
Laterality
Left	72	44
Right	78	46
Size of renal mass (cm)	3.0 (1.1–6.5)	3.4 (1.5–6.5)
RENAL score	7.4 (4–11)	8.4 (4–11)
MAP score	1.7 (0–5)	1.8 (0–5)
Operative time (minutes)	209 (107–325)	219 (154–314)
WIT (minutes)	15.8 (0–40)	18.9 (10–40)
EBL (mL)	508 (100–5000)	581 (200–5000)
Hospital stay (days)	2.9 (1–25)	2.9 (1–7)

ASA = American Society of Anesthesiologists; BMI = body mass index; Cr = creatinine; CS = collecting system; EBL = estimated blood loss; MAP = Mayo Adhesive Probability; RAPN = robot-assisted partial nephrectomy; RENAL = radius, exophytic/endophytic, nearness to CS, and laterality; WIT = warm ischemia time.

Table 2 shows the pathology results for the patients who underwent RAPN and had CS entry. For the CR group, 46 (71.9%) were clear cell renal-cell carcinoma (RCC), 7 (10.9%) were papillary RCC, 6 (9.4%) were chromophobe RCC, and 5 (7.8%) were benign. For the SLR group, 14 (53.8%) were clear cell RCC, 3 (11.5%) papillary RCC, 2 (7.7%) chromophobe RCC, and 7 (26.9%) benign.

Table 2.

Pathology of Patients Who Had Collecting System Entry Identified During Robot-Assisted Partial Nephrectomy

	CR (n = 64)	SLR (n = 27)	Total
Malignant	59	19	78
Clear cell	46	14	60
Papillary	7	3	10
Chromophobe	6	2	8
Benign	5	8	13
Oncocytoma	5	4	9
AML	0	2	2
Other	0	2	2

AML = angiomyolipoma; CR = classical renorrhaphy; SLR = single-layer renorrhaphy.

Table 3 compares patient, tumor, and perioperative variables of patients who underwent CR or SLR. No statistically significant difference between groups was identified when looking at age, sex, BMI, ASA score, MAP score, RENAL nephrometry score, and tumor size. The CR group and SLR group had WITs of 19.6 and 17.3 minutes, respectively, which reached statistical significance (p = 0.04). No other perioperative variables, such as EBL, operative time, hospital stay, and duration of drain, revealed any statistically significant difference. No statistically significant difference in grade III or higher complications was noted between the groups. When grade III or higher bleeding complications were isolated, no significant difference was seen between the groups. No urine leaks were identified. No ureteral stents were placed in either group. Grade III and higher complications are described in Table 4.

Table 3.

Comparison of Patient, Tumor, and Perioperative Variables for Classical Renorrhaphy and Single-Layer Renorrhaphy

Variable	CR	SLR	p
No. of patients	64	26	—
No. of tumors	64	27	—
Age (years)	62 (38–83)	59 (35–77)	0.22
Sex
Male	39	11	0.16
Female	25	15
BMI (kg/m²)	29.9 (19.8–60.6)	31.7 (18.7–47.3)	0.31
ASA score	2.8 (2–4)	2.7 (2–4)	0.26
Preoperative Cr (mg/dL)	1.0 (0.6–2.2)	1.0 (0.5–2.5)	0.36
Laterality
Left	29	15	0.35
Right	35	11
Size of renal mass (cm)	3.4 (1.5–6.0)	3.3 (1.7–6.5)	0.61
RENAL score	8.5 (5–11)	8.0 (4–10)	0.16
MAP score	1.8 (0–5)	1.8 (0–5)	0.95
Operative time (minutes)	222 (154–314)	211 (160–290)	0.18
WIT (minutes)	19.6 (11–40)	17.3 (10–31)	0.04
EBL (mL)	610 (200–5000)	505 (200–3500)	0.52
Drain time (days)	2.9 (1–13)	2.7 (1–9)	0.65
Hospital stay (days)	3.0 (1–6)	2.8 (1–7)	0.62
Complications (Grade III+)
IIIa	1	1	1.00
IIIb	2	1
IVa	0	0
IVb	0	0
V	1	0
Bleeding complications (Grade III+)	1	1	0.51

Table 4.

Clavien-Dindo Postoperative Complications for Classical Renorrhaphy and Single-Layer Renorrhaphy

Repair	Complication grade	Description
CR	IIIa	Myocardial infarction requiring cardiac catheterization
	IIIb	Pseudoaneurysm requiring IR embolization
	IIIb	Retained surgical drain
	V	Fatal myocardial infarction on POD3
SLR	IIIa	Delayed hemorrhage requiring IR embolization
	IIIb	Small bowel obstruction secondary to spigelian hernia requiring laparoscopic repair

IR = interventional radiology; POD = postoperative day.

Renal function results are detailed in Table 5. Preoperative creatinine was 1.03 and 0.96 for the CS repair and non-CS repair groups, respectively. Preoperative GFR was 71.9 and 76.7 for the CS repair and non-CS repair groups, respectively. No significant difference was identified with either creatinine or GFR between the CS repair and non-CS repair groups at 1 day, 1 month, 6 months, 1 year, and 2 years postoperatively.

Table 5.

Renal Function Comparison of Classical Renorrhaphy and Single-Layer Renorrhaphy

Variable	CR	SLR	p
Preoperative Cr (mg/dL)	1.03 (n = 64)	0.96 (n = 26)	0.36
Preoperative GFR (mL/min/BSA)	71.9	76.7	0.29
POD1 Cr (mg/dL)	1.24 (n = 64)	1.15 (n = 26)	0.37
POD1 GFR (mL/min/BSA)	60.7	63.0	0.64
1 month Cr (mg/dL)	1.13 (n = 60)	1.08 (n = 24)	0.53
1 month GFR (mL/min/BSA)	65.7	70.3	0.39
6 month Cr (mg/dL)	1.15 (n = 49)	1.04 (n = 19)	0.18
6 month GFR (mL/min/BSA)	64.2	68.1	0.43
1 year Cr (mg/dL)	1.18 (n = 41)	0.98 (n = 12)	0.08
1 year GFR (mL/min/BSA)	61.5	69.3	0.23
2 year Cr (mg/dL)	1.18 (n = 25)	1.07 (n = 6)	0.40
2 year GFR (mL/min/BSA)	59.7	60.3	0.94

BSA = body surface area; GFR = glomerular filtration rate.

Discussion

Many surgical innovators have fine-tuned the steps of RAPN, resulting in continued outcome improvement with decreased operative morbidity and less deterioration of renal function. In 2009, Benway and colleagues detailed the steps of the sliding-clip renorrhaphy to minimize cumbersome knot tying following RAPN.⁶ Sliding-clip renorrhaphy, compared to simple suture closure, has been shown to allow nearly thrice the applied force before renal parenchyma tearing.¹³ The technique has near universal usage today among urologists performing RAPN.

Modifications of renorrhaphy technique have been developed with the primary aim of minimizing WIT. The use of barbed sutures has been advocated to reduce the time wasted to retighten suture lines.^14,15 Another technique aims to curtail the surgeon's dependency on the first assistant during clamping.¹⁶ They describe placing multiple sutures intracorporeally before clamping so that the robotic surgeon can set the pace of the renorrhaphy. Some have attempted to omit presumably unnecessary procedural steps. Notably, Kaouk and colleagues detailed their evolving renorrhaphy technique that focused on elimination of surgical bolsters.¹⁷

More recently and similar to this study, Bahler and colleagues and Bylund and colleagues have both shown SLR to be safe.^7,18 Bahler's SLR technique differs from the current study in that it reapproximates the CS and the deep layer, but omits the outer layer, that is, renal cortex repair. Alternatively, Bylund and colleagues are similar to this study in that it omits the CS repair and instead only reapproximates the renal cortex. Whereas Bylund and colleagues differ in that their series was exclusively hand-assisted laparoscopic partial nephrectomy instead of RAPN. Bahler and colleagues concluded that SLR does not appear to increase urine leakage or bleeding complications. Other significant findings were that omission of cortical renorrhaphy led to improvements in percentage of renal volume loss. Moreover, Bylund and colleagues showed rates comparable to other series for urine leakage (1.9%), blood transfusion (4.8%), and delayed hematuria (1.9%). This study's results combined with the other two mentioned hint that classical two-layer renorrhaphy may not be necessary. However, whether omitting cortical renorrhaphy or CS repair is better cannot be concluded since no direct comparison exists. Debating the advantages of either would be largely theoretical. One would presume that omitting the deep layer may predispose to urine leak. However, this was not supported by our data. Alternatively, one may conjecture that omitting the cortical renorrhaphy would lead to increased bleeding complications. However, this was not supported by the results from Bahler and colleagues.

With regard to renal function, the findings from this study show no significant difference sustained for several years after RAPN when comparing the CR with SLR groups. One potential advantage of omitting CS repair is decreased WIT, which was identified in our study. This decreased WIT occurred without change in hospital stay, drain time, or complication rates. It should be noted that despite the decreased WIT, both groups already had an acceptable WIT, which would explain the absence of difference in functional outcomes. These findings are consistent with many studies that demonstrate complete recovery of the majority of nephrons with limited WIT.^19
–21

Loss of renal volume following RAPN has also been shown by multiple studies to possibly be even more important in determining long-term renal function.^22,23 In theory, preservation of renal volume by fewer suture lines is a primary reason why SLR has been suggested. More specifically, increasing the number of suture lines has been hypothesized to increase the likelihood of strangulated parenchyma and segmental arteries.²⁴ While volumetric analysis was not performed in this study, it was conducted by Bahler and colleagues, who discovered an 8 cm³ less median percent volume loss for the nonrenorrhaphy group compared to the renorrhaphy group. They concluded that three things were important to consider during surgery to minimize renal function loss—reconstruction technique, the amount of healthy parenchyma excised, and WIT.

An astute reader will ask does SLR, or fewer suture lines, lead to more bleeding complications? Our results show no significant difference when looking at major bleeding complications specifically. Interestingly, some believe that it is the suturing of the tumor defect that causes puncture or laceration of arterioles that then develop into renal artery pseudoaneurysms (RAP) with time once the renorrhaphy is complete.²⁵ Others believe that RAP arise from a transected intrarenal arterial branch during resection, that is, in spasm at the time of surgery, which explains how it goes unrecognized. In simple terms, a pseudoaneurysm is defined as an artery with a false wall. Clinically, RAP may lead to significant delayed bleeding and often require percutaneous angioembolization. One recent meta-analysis has shown RAP following PN to occur at ∼1% and 1.96% for open and minimally invasive procedures, respectively.²⁶ While one study has suggested renal sinus or CS exposure during PN to be associated with a higher incidence of renal artery pseudoaneurysm,²⁷ our study does not reflect this. The reason for the higher rate following minimally invasive procedures is not completely known.

In addition to conventional means of controlling hemostasis, such as manual tamponade, electrocautery, or sutures, many commercial surgical hemostatic agents have been developed over the past couple of decades. A variety of dressings and surgical sealants are available from plant, animal, or mineral origins. Most of these agents have been used to aid in controlling hemostasis during RAPN.²⁸ However, objective evidence demonstrating the benefit of these agents is lacking.

One limitation to this study is that the sample size is smaller in comparison to other published series. This possibly could explain why no urine leaks were identified. However, our results are comparable with a recent large multicenter analysis that shows urine leak rates following RAPN to be <1%.²⁹ It is possible and even likely that with a larger sample size a difference in urine leak between the two groups would be identified. Furthermore, closed-suction drains were placed near routinely in this series. This may be overkill, but also may partly contribute to the absence of urine leaks. It should be noted that the lower incidence seen with newer studies has motivated some to omit routine drain placement with RAPN.^30,31 Our practice too has evolved since the publication of these data.

Other limitations to this study are intrinsic in its retrospective design and its inherent selection bias. It is important to note that the decision to omit CS repair was without any randomization and performed at the surgeon's discretion at the time of surgery. Most large defects, that is, >1 cm, warranted CS repair. CS closure was omitted in circumstances where difficult suturing angles were present or when WIT was approaching 20 minutes. While these results suggest that SLR may be conducted safely, it should not be extended to all situations.

Finally, no SLR was performed in the first 30 cases recorded in this series. It is possible that the surgeon's learning curve explains the lower WIT within the SLR group.

Conclusion

Results of this study suggest that formal CS closure following tumor excision may be safely omitted during RAPN when performing cortical renorrhaphy with the sliding-clip technique. Omitting this step does decrease WIT, although the overall effect on short- and long-term renal function remains to be seen.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

Abbreviations Used

References

Ghani

, Sukumar

, Sammon

, et al. Practice patterns and outcomes of open and minimally invasive partial nephrectomy since the introduction of robotic partial nephrectomy: Results from the nationwide inpatient sample. J Urol, 2014; 191:907–912.

Patel

, Mullins

, Pierorazio

, et al. Trends in renal surgery: Robotic technology is associated with increased use of partial nephrectomy. J Urol, 2013; 189:1229–1235.

Kardos

, Gross

, Shah

, et al. Association of type of renal surgery and access to robotic technology for kidney cancer: Results from a population-based cohort. BJU Int, 2014; 114:549–554.

Mir

, Ercole

, Takagi

, et al. Decline in renal function after partial nephrectomy: Etiology and prevention. J Urol, 2015; 193:1889–1898.

Becker

, Van Poppel

, Hakenberg

, et al. Assessing the impact of ischaemia time during partial nephrectomy. Eur Urol, 2009; 56:625–634.

Benway

, Wang

, Cabello

, et al. Robotic partial nephrectomy with sliding-clip renorrhaphy: Technique and outcomes. Eur Urol, 2009; 55:592–599.

Bylund

, Clark

, Crispen

, et al. Hand-associated laparoscopic partial nephrectomy without formal collecting system closure: Perioperative outcomes in 104 consecutive patients. J Endourol, 2011; 25:1853–1857.

Davidiuk

, Parker

, Thomas

, et al. Mayo Adhesive Probability score: An accurate image-based scoring system to predict adherent perinephric fat in partial nephrectomy. Eur Urol, 2014; 66:1165–1171.

Kutikov

, Uzzo

. The RENAL nephrometry score: A comprehensive standardized system for quantifying renal tumor size, location, and depth. J Urol, 2009; 182:844–853.

10.

Clavien

, Sanabria

, Strasberg

. Proposed classification of complications of surgery with examples of utility in cholecystectomy. Surgery, 1992; 111:518–526.

11.

Levey

, Bosch

, Lewis

, et al. A more accurate method to estimate glomerular filtration rate from serum creatinine: A new prediction equation. Ann Intern Med, 1999:130:461–470.

12.

Taylor

, Lee

, Rawal

, et al. Impact of fellowship training on robotic-assisted laparoscopic partial nephrectomy: Benchmarking perioperative safety and outcomes. J Robot Surg, 2015; 9:125–130.

13.

Benway

, Cabello

, Figenshau

, et al. Sliding-clip renorrhaphy provides superior closing tension during robot-assisted partial nephrectomy. J Endourol, 2010; 24:605–608.

14.

Sammon

, Petros

, Sukumar

, et al. Barbed suture for renorrhaphy during robot-assted partial nephrectomy. J Endourol, 2011; 25:529–533.

15.

Erdem

, Tefik

, Mammadov

, et al. The use of self-retaining barbed suture for inner layer renorrhaphy significantly reduces warm ischemia time in laparoscopic partial nephrectomy: Outcomes of a matched-pair analysis. J Endourol, 2013; 27:452–458.

16.

Berg

, Rich

, Badalato

, et al. The first assistant sparing technique robot-assisted partial nephrectomy decreases warm ischemia time while maintaining good perioperative outcomes. J Endourol, 2012; 26:1448–1453.

17.

Kaouk

, Hillyer

, Autorino

, et al. 252 robotic partial nephrectomies: Evolving renorrhaphy technique and surgical outcomes at a single institution. Urology, 2011; 78:1338–1344.

18.

Bahler

, Dube

, Flynn

, et al. Feasibility of omitting cortical renorrhaphy during robot-assisted partial nephrectomy: A matched analysis. J Endourol, 2015; 29:548–555.

19.

Song

, Bank

, Park

, et al. Factors influencing renal function reduction after partial nephrectomy. J Urol, 2009; 181:48–53.

20.

Song

, Park

, Jeong

, et al. Followup of unilateral renal function after laparoscopic partial nephrectomy. J Urol, 2011; 196:53–58.

21.

Lane

, Russo

, Uzzo

, et al. Comparison of cold and warm ischemia during partial nephrectomy in 660 solitary kidneys reveals predominant role of nonmodifiable factors in determining ultimate renal function. J Urol, 2011; 185:421–427.

22.

Mir

, Campbell

, Sharma

, et al. Parenchymal volume preservation and ischemia during partial nephrectomy: Functional and volumetric analysis. Urology, 2012; 82:263–268.

23.

Simmons

, Hillyer

, Lee

, et al. Functional recovery after partial nephrectomy: Effects of volume loss and ischemic injury. J Urol, 2012; 187:1667–1673.

24.

Thompson

, Lane

, Lohse

, et al. Renal function after partial nephrectomy: Effect of warm ischemia relative to quantity and quality of preserved kidney. Urology, 2012; 79:356–360.

25.

Singh

, Gill

. Renal artery pseudoaneurysm following laparoscopic partial nephrectomy. J Urol, 2005; 174:2256–2259.

26.

Jain

, Nyirenda

, Yates

, et al. Incidence of renal artery pseudoaneurysm following open and minimally invasive partial nephrectomy: A systematic review and comparative analysis. J Urol, 2013; 189:1643–1648.

27.

Omae

, Kondo

, Takagi

, et al. Renal sinus exposure as an independent factor predicting asymptomatic unruptured pseudoaneurysm formation detected in the early postoperative period after minimally invasive partial nephrectomy. Int J Urol, 2015; 22:356–361.

28.

Morelli

, Morelli

, Palmeri

, et al. Robotic surgery and hemostatic agents in partial nephrectomy: A high rate of success without vascular clamping. J Robot Surg, 2015; 9:215–222.

29.

Potretzke

, Knight

, Zargar

, et al. Urinary fistula after robot-assisted partial nephrectomy: A multicenter analysis of 1791 patients. BJU Int, 2016; 117:131–137.

30.

Williams

, Snowden

, Thiel

. Assessment of perioperative variables that predict the need for surgical drain following robotic partial nephrectomy utilizing quantitative drain creatinine analysis. J Laparoendosc Adv Surg Tech A, 2016. [Epub ahead of print]; DOI: 10.1089/lap.2016.0417.

31.

Abaza

, Prall

. Drain placement can be safely omitted after the majority of robotic partial nephrectomies. J Urol, 2013; 189:823–827.