Retroperitoneal Laparoscopic Radical Nephrectomy for Large (>7 cm) Solid Renal Tumors: Comparison of Perioperative Outcomes with the Transperitoneal Approach

Abstract

Purpose:

To describe our technique for retroperitoneal laparoscopic radical nephrectomy (LRN) and to present the perioperative outcomes of our retroperitoneal LRN series for large (>7 cm) solid renal tumors and to compare them with those of the transperitoneal approach.

Materials and Methods:

A retrospective chart review was performed for patients who had undergone LRN for a solid renal tumor greater than 7 cm in size on computed tomography (CT) scans between June 2008 and January 2016. Perioperative outcomes were compared between transperitoneal and retroperitoneal approaches.

Results:

There were 30 cases in the transperitoneal approach group and 34 cases in the retroperitoneal group. The mean tumor size was 9.0 cm in the transperitoneal approach group and 10.3 cm in the retroperitoneal group (P = .494). In the retroperitoneal approach group, the operation time was shorter, estimated blood loss (EBL) was lower, and time to start diet was shorter (P < .001, P = .037, and P = .002, respectively). The complication rate was comparable between the two approaches.

Conclusions:

Retroperitoneal LRN for a large (>7 cm) solid renal tumor demonstrated a superior result in terms of operation time, estimated blood loss, and time to start diet than transperitoneal LRN. Other perioperative outcomes and complication rate were comparable between the two approaches. We believe that with sufficient experience, retroperitoneal LRN may be an effective and safe procedure for large (>7 cm) solid renal tumors.

Introduction

The first-line treatment for a large solid renal tumor (>7 cm) is radical nephrectomy.¹ It is usually performed in cases without distant metastasis for curative purpose, but it is also performed in cases with distant metastasis for cytoreductive purpose.² In the past, surgery for a large solid renal tumor was usually performed via the open technique. However, with the advent of minimally invasive surgery, laparoscopy is being utilized frequently for these large solid renal tumors, showing equivalent survival and improved convalescence.^3,4

However, laparoscopic surgery for a large solid renal tumor can be quite challenging. Currently, there is no guideline regarding the surgical method for laparoscopic radical nephrectomy (LRN) for renal tumors, but the transperitoneal method is preferred to the retroperitoneal method mainly because of the large working space it can offer.⁵ The retroperitoneal method is less utilized despite the advantage of avoidance of bowel mobilization and fast pedicle control, largely because of the small working space. Hence, there are only a few articles reporting the outcomes for retroperitoneal laparoscopic procedure for large renal tumors.^6,3

In the current study, we describe our technique for retroperitoneal LRN. In addition, we present the perioperative outcomes of our retroperitoneal LRN series for large (>7 cm) solid renal tumors and compare them with those of the transperitoneal approach to highlight the advantages of the retroperitoneal approach.

Materials and Methods

Patient selection

The Institutional Review Board of St. Vincent's Hospital at the Catholic University of Korea approved the study protocol. A retrospective chart review was performed for patients who had undergone LRN for a solid renal tumor greater than 7 cm in size on computed tomography (CT) scans between June 2008 and January 2016. Patients who had undergone concomitant thrombectomy were excluded.

Surgical procedure

Standard technique was used for transperitoneal LRN.⁷ The specifics of transperitoneal LRN will not be discussed in the current study as they are well known. We will describe our technique for retroperitoneal LRN. It is also well described in previous studies,⁸ but we have made some modifications to the procedure that are discussed hereafter.

The patient is placed in a full flank position with the table fully flexed to maximize the space between the iliac crest and the 12th rib. A 1.2-cm-long skin incision is made ∼2 finger widths above the iliac crest on the middle axillary line. A Kelly clamp is used to bluntly open the flank muscular layers and puncture the lumbodorsal fascia. A balloon-dilating device (Covidien OMSPDBS2, Mansfield, MA) is inserted and inflated to create the retroperitoneal space. The device is then removed and a 12 mm balloon trocar (Covidien OMST12BT, Mansfield, MA) is inserted. Using the Stryker 40 L High Flow Insufflator (Stryker Endoscopy, San Jose, CA), carbon dioxide gas is insufflated, and the pressure is set at 12 mmHg and the flow rate is set at 20 L/min. A 30° laparoscopic camera is inserted. The second port is inserted below the tip of the 12th rib, and the third port is inserted lateral to the camera port on the anterior axillary line (Fig. 1).

FIG. 1.

Port placement in a right retroperitoneal laparoscopic radical nephrectomy. The dotted line depicts the iliac crest caudally, the 12th and 11th rib cranially, and anterior, middle, and posterior axillary lines as horizontal lines, respectively. C = 12 mm balloon trocar for camera.

The camera is rotated such that the psoas muscle is in a horizontal plane. This is a crucial step to keep the surgeon oriented, especially in cases of a huge (usually greater than 10 cm) renal mass that will inevitably occupy a large area of a relatively limited retroperitoneal space. The first step is identification and dissection of the main renal artery. Gerota's fascia is bluntly dissected above the psoas muscle at the level of the kidney, and using a laparoscopic forceps in the nondominant hand, the kidney is lifted upward to stretch the renal hilum. This maneuver usually reveals the pulsation of the renal artery. The renal artery is then dissected, skeletonized, clipped, and divided. The renal vein usually lies behind the renal artery. It is also dissected and divided with a gastrointestinal anastomosis vascular stapler. However, the renal vein is not always divided at this point because large renal tumors occasionally have parasitic vessels around the kidney. If the main renal vein is divided before controlling these parasitic vessels, not only the kidney may become swollen due to the incoming blood supply, which can make the operation more difficult, but also the divided renal vein may burst open, causing major bleeding. Therefore, the main renal vein is divided only when it is absolutely sure that all arterial blood supply is controlled.

After dividing the main renal vessels, the remaining kidney is dissected, paying special attention so as not to breach open the peritoneum in the process, which will shrink the retroperitoneal space. In cases of peritoneal breaching, a Veress needle is inserted into the peritoneal space to drain the resultant gas, and when this is not sufficient, changing the method to a transperitoneal approach is considered. Also, in locally advanced cases where peritoneal invasion is suspected, the overlying peritoneum may need to be removed intentionally.

En bloc removal of the adrenal gland is performed, while ensuring that the adrenal vein is properly controlled. The ureter is also dissected and divided. The specimen is placed into a laparoscopic specimen retrieval bag and it is removed through a Gibson incision. In cases of huge (>10 cm) renal masses, the incision length must be adequate enough to ensure that the specimen bag does not tear open during extraction, which will result in tumor spillage.

Data analysis

Patient characteristics, tumor characteristics, and perioperative outcomes were recorded, and descriptive statistics were used to describe the results. Patient age, body mass index, sex, American Society of Anesthesiologists (ASA) physical status score, history of diabetes mellitus, history of hypertension, and history of chronic kidney disease were recorded as patient characteristics. Tumor size, laterality, and clinical stage defined by the TNM staging system were recorded as tumor characteristics. Operation time, estimated blood loss (EBL), days after the operation when the patients started oral intake, period of admission, rate of intraoperative transfusion, rate of open conversion, and complications classified by the Clavien–Dindo system⁹ were recorded as perioperative outcomes. The study population was divided into the following two groups: patients who had undergone transperitoneal LRN and patients who had undergone retroperitoneal LRN. Comparison of continuous variables was performed using the unpaired t-test or the Mann–Whitney test, and comparison of categorical variables was performed using the chi-square test or the Fisher's exact test. PASW (Predictive Analytics Software) Statistics for Macintosh, version 21.0 (IBM Corp., Armonk, NY), was used for statistical analysis.

Results

The comparison of patient and tumor characteristics between the transperitoneal and retroperitoneal approach groups is described in Table 1. There was no statistically significant difference between the two groups in terms of patient characteristics except for a history of hypertension (26.7% in the transperitoneal group vs. 64.7% in the retroperitoneal group, P = .003). There was no statistically significant difference between the two groups in terms of tumor characteristics.

Table 1.

Patient and Tumor Characteristics

	Transperitoneal (n = 30)	Retroperitoneal (n = 34)	P
Age (mean ± SD)	56.1 ± 12.5	58.9 ± 12.1	.365^a
BMI (mean ± SD)	22.8 ± 2.8	24.5 ± 4.2	.092^b
Sex (%)			.591^c
Male	22/30 (73.3)	22/34 (64.7)
Female	8/30 (26.7)	12/34 (35.3)
ASA score (%)
I	5/30 (16.7)	6/34 (17.6)	1.000^c
II	20/30 (66.7)	22/34 (64.7)	1.000^c
III	5/30 (16.7)	6/34 (17.6)	1.000^c
DM (%)	4/30 (13.3)	9/34 (26.5)	.228^c
Hypertension (%)	8/30 (26.7)	22/34 (64.7)	.003^c
CKD (%)	0/30 (0.0)	2/34 (5.9)	.538^d
Tumor size (mean ± SD)	9.0 ± 1.5	10.3 ± 3.7	.494^b
Tumor laterality (%)			.314^c
Left	20/30 (66.7)	18/34 (52.9)
Right	10/30 (33/3)	16/34 (47.1)
Clinical stage (%)
T
T2a	15/30 (50.0)	13/34 (38.2)	.450^c
T2b	3/30 (10.0)	4/34 (11.8)	1.000^d
T3a	3/30 (10.0)	8/34 (23.5)	.195^c
T3b	3/30 (10.0)	1/34 (2.9)	.333^d
T4	6/30 (20.0)	7/34 (20.6)	1.000^c
N
N0	19/30 (63.3)	23/34 (67.6)	.795^c
N1	8/30 (26.7)	10/34 (29.4)	1.000^c
N2	3/30 (10.0)	0/34 (0.0)	.097^d
M			1.000^d
M0	27/30 (90.0)	30/34 (88.2)
M1	3/30 (10.0)	3/34 (8.8)

Unpaired t-test.

Mann–Whitney test.

Chi-square test.

Fisher's exact test.

ASA, American Society of Anesthesiologists; BMI, body mass index; CKD, chronic kidney disease; DM, diabetes mellitus; SD, standard deviation.

The comparison of perioperative results between the transperitoneal and retroperitoneal approach groups is described in Table 2. A statistically significant difference was observed in operation time, EBL, and time to start diet. Operation time was shorter in the retroperitoneal group, with an operation time of 303.2 ± 68.4 (mean ± standard deviation) minutes in the transperitoneal approach versus 221.1 ± 73.6 min in the retroperitoneal group (P < .001). There was less EBL in the retroperitoneal group, with 828.2 ± 762.7 mL in the transperitoneal group versus 621.2 ± 613.4 mL in the retroperitoneal group (P = .037). Time to start diet was shorter in the retroperitoneal group, with 2.6 ± 0.8 days in the transperitoneal group versus 1.9 ± 0.6 days in the retroperitoneal group (P = .002). There was no difference in period of admission, intraoperative transfusion rate, open conversion rate, and complication rate between the two approaches. The single grade IIIb complication in the transperitoneal group was a case of laparoscopic exploration at postoperative day 2 because of suspected postoperative bleeding. The two grade IIIb complications in the retroperitoneal group were cases of diaphragmatic tear during the operation that eventually required diaphragm repair and chest tube insertion.

Table 2.

Comparison of Perioperative Results Between Transperitoneal and Retroperitoneal Approach Groups

	Transperitoneal	Retroperitoneal	P
Operation time, minutes, mean ± SD	303.2 ± 68.4	221.1 ± 73.6	< .001^a
EBL, mL, mean ± SD	828.2 ± 762.7	621.2 ± 613.4	0.037^b
Start of diet, days, mean ± SD	2.6 ± 0.8	1.9 ± 0.6	0.002^b
Period of admission, days, mean ± SD	8.3 ± 1.8	8.4 ± 3.7	0.280^b
Intraoperative transfusion (%)	8/30 (26.7)	11/34 (32.4)	0.785^c
Open conversion (%)	2/30 (6.7)	3/34 (8.8)	1.000^d
Pathology (%)
RCC	26/30 (86.7)	31/34 (91.2)	0.697^d
Complications (%)
None	21/30 (70.0)	24/34 (70.6)	1.000^c
Grade I	2/30 (6.7)	2/34 (5.9)	1.000^d
Grade II	6/30 (20.0)	6/34 (17.6)	1.000^c
Grade IIIb	1/30 (3.3)	2/34 (5.9)	1.000^d

Unpaired t-test.

Mann–Whitney test.

Chi-square test.

Fisher's exact test.

EBL, estimated blood loss; RCC, renal-cell carcinoma; SD, standard deviation.

Discussion

Surgery for a large renal tumor is a challenging procedure for even the experienced surgeons due to several reasons: first, a large tumor reduces the working space, with an increased chance of disorientation; second, approach to the renal hilum becomes more difficult due to an increased chance of prominent nodal disease; third, bleeding risk increases due to abundance of parasitic vessels; finally, the risk of involvement of adjacent organs increases.⁴ Therefore, the transperitoneal approach is usually preferred to the retroperitoneal approach because it offers a larger working space, the surrounding structures are relatively familiar to urologists, and it provides flexibility to surgeons in inserting additional ports if necessary.^10,5,11

On the contrary, the retroperitoneal approach has the advantages of gaining direct approach to the renal vessels and avoidance of peritoneal complications (ileus, bowel injury, etc.), which can compensate for the relatively limited working space.³ For T1 tumors, it has proven to be comparable, or even superior in some aspects, to the transperitoneal approach in terms of oncologic/perioperative outcomes, safety, and convalescence.^12–14 However, for large renal tumors greater than 7 cm, there is paucity of reports on utilization of the retroperitoneal approach. In 2000, Dunn et al. presented their experience of 61 laparoscopic radical nephrectomies for tumors stratified by size up to 10 cm.¹⁵ Again in 2000, Gill et al. demonstrated the feasibility with 53 retroperitoneoscopic radical nephrectomies for tumors up to 12 cm, although the mean tumor size was 4.6 cm in their series.⁸ The study by Steinberg et al. in 2004 was the only study that compared retroperitoneal LRN with transperitoneal LRN for large renal tumors. In that study, they found no difference between the retroperitoneal and transperitoneal approaches for T2 tumors in terms of perioperative and postoperative outcomes.⁶ Interestingly, Srivastava et al. introduced a combined approach of retroperitoneal renal artery clipping followed by transperitoneal nephrectomy for very large T2 tumors.¹⁶

In the current study, we compared perioperative outcomes of retroperitoneal LRN with those of transperitoneal LRN for large (>7 cm) solid renal tumors. As a result, retroperitoneal LRN showed better results in terms of operation time, EBL, and time to start diet than the transperitoneal approach. Other perioperative outcomes and complication rates were comparable between the two approaches. We believe that technical characteristics that are unique for the retroperitoneal approach, such as fast pedicle control and the lack of need for bowel mobilization, contributed to these favorable results. Early control of renal pedicle can not only lower blood loss during further steps of dissection but can also reduce the operation time by facilitating dissection due to reduced bleeding and release of the kidney from the renal pedicle.¹⁷ Also, because bowel manipulation is unnecessary, operation time and complications such as ileus are reduced, resulting in early start of diet with use of the retroperitoneal approach. From these results, we believe that retroperitoneal LRN is an effective and safe procedure for large (>7 cm) solid renal tumors.

Technically, we have made some modifications to the well-known retroperitoneal series.⁸ First, regarding port placement, our camera port was placed in a more caudal position than that in Gill's series. We believe this helped us in obtaining more area of retroperitoneal space, especially in cases of a huge (>10 cm) renal tumor. Second, as mentioned in the “Materials and Methods” section, we did not routinely control the renal vein early in the procedure, as there may be other feeding vessels around the kidney; dividing the main renal vein without controlling these parasitic vessels might result in severe bleeding, which might be one of the potential causes of open conversion. Finally, we were able to successfully operate on a significant number of huge (>10 cm) renal masses using the retroperitoneal approach. There were 12 cases of retroperitoneal LRN with a tumor size greater than 10 cm, the largest tumor size being 20.4 cm. This implies that tumor size may not be a limiting factor for the retroperitoneal approach due to its relatively small working space, as some other studies have suggested. However, we admit that retroperitoneal laparoscopic surgery for large renal tumors requires significant surgical skills and experience, and we suggest that one should gain sufficient experience in simpler cases of retroperitoneal surgeries before considering more complicated cases.

There are some limitations in this study. First, this was a retrospective study with a relatively small sample size. Second, the data were not randomized and the decision to operate using a certain approach was arbitrary. However, with the exception of a history of hypertension, the patient and tumor characteristics were statistically similar between the two approaches. Third, the series included our early experiences of laparoscopic surgeries; therefore, our results of operation time and EBL may be somewhat higher than those in a previous series. Finally, we did not provide survival data. This was because the series included some cases that were not of renal cell cancers and also the series was mixed with surgeries performed with a curative intent for locally advanced tumors without distant metastasis and surgeries performed with a cytoreductive intent for tumors with distant metastasis.

Conclusions

Our retroperitoneal LRN series for a large (>7 cm) solid renal tumor demonstrated a superior result in terms of operation time, estimated blood loss, and time to start diet than transperitoneal LRN. Other perioperative outcomes and complication rates were comparable between the two approaches. From the results of our study, we believe that with sufficient experience, retroperitoneal LRN may be an effective and safe procedure for large (>7 cm) solid renal tumors.

Footnotes

Disclosure Statement

No competing financial interests exist.

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