Robot-Assisted Partial Nephrectomy for Patients with Multifocal Renal Tumors Arising in a Solitary Kidney: Report of Three Cases

Abstract

Background: Surgical treatment of synchronous multifocal renal tumors arising in a solitary kidney remains an extremely unique and stressful challenge, since it is not easy to completely remove multiple tumors and effectively preserve the renal function without perioperative complications. In this report, we describe our experience of three patients with multifocal renal tumors detected in a solitary kidney who were treated by robot-assisted partial nephrectomy (RAPN).

Case Presentation: Two men and one woman were found to have two small renal tumors in a solitary kidney, and subsequently underwent RAPN at our institution. The location of the renal tumors and surgical approach in each patient were as follows: one tumor on the abdominal side and another on the dorsal side with a transperitoneal approach, both on the abdominal side with a transperitoneal approach, and both on the dorsal side with a retroperitoneal approach. In this series, after clamping the main renal artery and resection of one tumor, an inner running suture was placed, followed by early declamping of the renal artery and then renorrhaphy, and the same procedure was repeated to manage the remaining tumor. In all patients, the trifecta outcomes were achieved, and there were no changes in the chronic kidney disease stage 1 month after RAPN, resulting in no requirement of postoperative dialysis.

Conclusion: Although it is necessary to carefully select optimal candidates, RAPN with an early declamping technique could be a safe and feasible approach for the treatment of patients with synchronous multifocal renal tumors arising in a solitary kidney, facilitating the complete resection of tumor foci, minimization of warm ischemic injury, and effective preservation of the renal function.

Introduction

Partial nephrectomy (PN) is regarded as the standard of care for patients with localized small renal tumors, since it has been shown to provide equivalent cancer control as well as superior renal functional outcomes when compared with radical nephrectomy. Of several surgical options for PN, robot-assisted PN (RAPN) has become prevalent because of the significant improvement of perioperative outcomes, and thus RAPN has been widely applied to patients with complex renal tumors. However, it remains controversial whether synchronous multifocal tumors in an ipsilateral kidney should be managed by RAPN, particularly those arising in a solitary kidney, considering its surgical complexity.

In this report, we present our experience of three patients with two synchronous small renal tumors arising in a solitary kidney who were treated by RAPN.

Case Presentation

Table 1 summarizes the characteristics of the three patients described in this report. Preoperative radiologic findings in these patients, including CT and three-dimensional images, are presented in Figure 1. In this series, RAPN was performed by a single trained surgeon (H.M.) with the same procedure in all patients, as previously reported.¹ In brief, after clamping the main renal artery with the Bulldog, one tumor was resected using cold scissors while maintaining a secure margin of ∼5 mm, and an inner running suture with 3–0 V-Loc (COVIDIEN Japan, Inc., Tokyo, Japan) was carried out to repair the opened collecting system and large vessels. After early declamping of the renal artery, inner suturing and/or soft coagulation with a monopolar electrode (VIO300D; ERBE Elektromedizin GmbH, Tübingen, Germany) was then added to control the bleeding from interlobar or segmental arteries, followed by renorrhaphy with 2–0 V-Loc. The same procedure, including the management of renal artery, was then repeated for the resection of the remaining tumor. However, in one patient (case 1), after the procedure for the tumor on the abdominal side, the kidney was inverted by completely excising the connecting and fatty tissues surrounding it, and the tumor on the dorsal side was managed.

Table 1.

Baseline Characteristics

Variables	Case 1	Case 2	Case 3
Age (years)	63	69	67
Gender	Female	Male	Male
Reason for solitary kidney	Nephrouretectomy for ureteral cancer	Nephrectomy for pyonephrosis	Nephrectomy for RCC
eGFR (mL/min per 1.73 m2)	44	51	58
CKD stage	3	3	3
Tumor side	Left	Right	Right
Tumor location	Abdominal/dorsal	Abdominal/abdominal	Dorsal/dorsal
Tumor size (mm)	10/25	20/25	12/17

CKD = chronic kidney disease; eGFR = estimated glomerular filtration rate; RCC = renal cell carcinoma.

FIG. 1.

(A, B) CT showing tumor foci in case 1. Arrows indicate tumors. (C) 3D image reconstructed from the DICOM data of CT images for case 1 using the SYNAPSE VINCENT system (FUJIFILM, Inc., Tokyo, Japan). (D, E) CT showing tumor foci in case 2. Arrows indicate tumors. (F) 3D image reconstructed from the DICOM data of CT images for case 2 using the SYNAPSE VINCENT system. (G, H) CT showing tumor foci in case 3. Arrows indicate tumors. (I) 3D image reconstructed from the DICOM data of CT images for case 3 using the SYNAPSE VINCENT system. 3D, three-dimensional; DICOM, digital imaging and communications in medicine.

Table 2 shows perioperative and pathologic findings in these three patients. In all three patients, the warm ischemia time was <25 minutes, and no significant complication, except for temporary impairment of the renal function, was noted during and after RAPN. Furthermore, pathologic examinations revealed that five tumors were renal cell carcinomas and the remaining one was a benign cyst, and their resected margins were negative. Therefore, trifecta outcomes were achieved in all patients. Figure 2 shows findings of CT performed 3 days after RAPN in these three patients.

Table 2.

Perioperative and Pathologic Findings

Variables	Case 1	Case 2	Case 3
Surgical approach	Transperitoneal	Transperitoneal	Retroperitoneal
Console time (minutes)	109	150	107
Warm ischemia time (minutes)a	14	15	15
Estimated blood loss (mL)	100	5	10
Complicationb	None	None	None
Histopathology	Papillary RCC type 1/papillary RCC type 1	Clear cell RCC Benign cyst	Clear cell RCC/clear cell RCC
Positive surgical margin	Negative/negative	Negative/negative	Negative/negative
Postoperative eGFR (% of decrease)
1 day after surgery	27 (38.6)	16 (68.6)	30 (48.3)
1 week after surgery	30 (31.8)	14 (72.5)	32 (44.8)
1 month after surgery	31 (29.5)	35 (31.4)	38 (34.5)
CKD stage 1 month after surgery	3	3	3

^aTotal warm ischemia times for both tumors.

^bComplication except for management for temporal impairment of renal function.

FIG. 2.

CT performed 3 days after robot-assisted partial nephrectomy. (A) Case 1. (B) Case 2. (C) Case 3.

As shown in Tables 1 and 2, preoperative estimated glomerular filtration rates in these three patients were relatively unfavorable because of a solitary kidney; however, there were no postoperative changes in the chronic kidney disease stage 1 month after RAPN in all patients who, thus, could avoid postoperative dialysis, even temporarily.

Discussion

Despite the prevalence of PN for small localized renal tumors, a minimally invasive procedure was mainly applied to straightforward cases, reserving open PN for relatively complex cases. In recent years, minimally invasive surgery using a robot-assisted platform has been expanded to complex renal tumors, including synchronous ipsilateral multiple tumors.² To date, there have been several studies showing favorable functional and oncologic outcomes of RAPN for those with multiple tumors. However, conflicting findings on this point were also described. For example, Maurice et al. analyzed the data from 1121 patients undergoing RAPN and found that the number of tumor excisions was independently associated with the increase in perioperative complications.³ Considering these findings, it remains controversial whether RAPN should be performed for patients with multiple ipsilateral tumors, particularly those with a solitary kidney.

It is well recognized that the renal function usually decreases by ∼20% after PN of a diseased kidney, and of several factors, warm ischemic injury plays one of the crucial roles affecting the postoperative renal functional outcomes. Currently, many novel approaches have emerged to reduce warm ischemic injury during PN, such as selective clamping, early declamping, zero-ischemia technique, and simple enucleation. For those with multiple tumors, it is extremely important to maximally preserve the postoperative renal function by introducing such novel approaches. At our institution, early declamping of the renal artery before renorrhaphy has been preferred during RAPN, since this was shown to decrease the warm ischemia time as well as perioperative complications, particularly renal artery pseudoaneurysm¹; therefore, early declamping was applied to the three patients described in this report, resulting in the achievement of satisfactory perioperative outcomes, including postoperative renal functions.

It is of interest to explore an alternative approach to more safely complete RAPN for patients with multiple tumors. One such approach is to avoid multiple excisions by simultaneously excising multiple tumors, which may help decrease the risk of perioperative complications, such as blood transfusion and urine leak. In fact, we considered the simultaneous excision of two tumors close to each other in case 3. However, the use of fewer excisions may sacrifice more normal kidney parenchyma and consequently impair the postoperative renal function; therefore, we did not use this approach on considering the risk of a markedly impaired postoperative renal functional status caused by a solitary kidney. Collectively, these findings suggest that the use of fewer excisions for multiple ipsilateral tumors should be determined based on the baseline renal function in each patient.

In this report, we would like to mention several limitations of this report. Initially, outcomes of PN, particularly those involving complex tumors, such as multiple ipsilateral tumors, are influenced by the case volume. The three patients in this report were operated by a high-volume surgeon; therefore, this should be recognized when interpreting the findings in these patients. Second, since ischemia reperfusion was shown to adversely influence the renal function by several mechanisms, such as oxidative stress injury,⁴ it might be interesting to consider additional approaches, including declamping of the renal artery after the excision and inner suture for both tumors, use of zero-ischemia technique without clamping of the renal artery and administration of effective diuretics. Third, because of the short observation period after RAPN, follow-up periods to assess changes in renal functions in these three patients were insufficient. Finally, it is necessary to investigate the role of nonsurgical approaches, including active surveillance, cryo-ablation and thermal ablation for multiple renal tumors in a solitary kidney, which could decrease surgical morbidity but with a slightly higher oncologic risk.

In this report, we describe our experience of three patients who were treated with RAPN with an early declamping technique for two synchronous small renal tumors arising in a solitary kidney. It is necessary to avoid radical nephrectomy, if at all possible, particularly in those with characteristics associated with strong indications for nephron-sparing surgery, such as multiple tumors in a solitary kidney; therefore, it is strongly recommended to apply RAPN to such patients as a standard surgical procedure on considering the feasibility and safety of our approach.

Abbreviations Used

CT

computed tomography

PN

partial nephrectomy

RAPN

robot-assisted partial nephrectomy

RCC

renal cell carcinoma

Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this article.

Cite this article as: Miyake H, Motoyama D, Matsushita Y, Watanabe H, Ito T, Sugiyama T, Otsuka A (2020) Robot-assisted partial nephrectomy for patients with multifocal renal tumors arising in a solitary kidney: report of three cases, Journal of Endourology Case Reports 6:4, 370–373, DOI: 10.1089/cren.2020.0102.