A Hybrid Retroperitoneal–Transperitoneal Approach for Robot‐Assisted Radical Nephrectomy: A Technical Report of Two Cases

ABSTRACT

Introduction

Robot‐assisted radical nephrectomy (RARN) can be performed using either transperitoneal or retroperitoneal approaches; however, each has inherent limitations, particularly in cases with complex hilar anatomy or post‐systemic therapy fibrosis.

Case Presentation

Hybrid RARN was performed in two patients with renal cell carcinoma, including one who had received systemic therapy. The procedure consisted of initial retroperitoneal dissection with secure control of the renal hilum, followed by a transperitoneal nephrectomy with an expanded field. This sequential approach enabled reliable vascular control and sufficient working space for tumor resection. Perioperative outcomes were comparable to conventional RARN.

Conclusion

This hybrid approach may enhance surgical flexibility and safety.

Keynote Message

• Robot‐assisted radical nephrectomy can be challenging in cases with complex hilar anatomy or post‐systemic therapy fibrosis.

• A hybrid retroperitoneal–transperitoneal approach may improve hilar control and intraoperative flexibility in selected patients.

1. Introduction

Robot‐assisted radical nephrectomy (RARN) is widely used as a minimally invasive surgical approach for renal cancer [1, 2, 3]. Recently, its indications have expanded to more complex cases, such as locally advanced tumors and those treated with preoperative systemic therapy [4, 5].

RARN can be performed via either a transperitoneal or retroperitoneal approach, each with advantages and limitations. The transperitoneal approach provides a wide operative field and good maneuverability; however, anatomical variations of the renal artery, tumor location, and adhesions may complicate identification and control of hilar vessels [6]. In addition, the renal artery lies posterior to the renal vein; a thick and short renal vein can restrict instrument movement and increase the risk of vascular injury and bleeding [7].

Conversely, the retroperitoneal approach allows direct access to the renal artery and facilitates rapid and safe identification and control of the hilar vessels [8, 9].

However, the working space is limited, and visualization and maneuverability may be restricted, particularly in cases with large tumors. In addition, depending on port placement, the range of motion of the robotic arms may be limited [8].

To address these limitations, we introduced a hybrid RARN technique that combines the advantages of the retroperitoneal and transperitoneal approaches. This technique involves initial retroperitoneal hilar dissection followed by transperitoneal nephrectomy.

In this report, we evaluated two cases in which this technique was performed, focusing on its feasibility and perioperative safety.

2. Materials and Methods

2.1. Surgical Technique and Hybrid Approach

The hybrid RARN technique was applied in our initial clinical cases (IRB Approval No. 25J14). All procedures were performed using the da Vinci Xi surgical system (Intuitive Surgical, Sunnyvale, CA, USA). This method involves switching from a retroperitoneal to an intraperitoneal approach after dissection of the renal artery and vein (Figure 2A,B), followed by nephrectomy via a transabdominal route. To access the peritoneal cavity, a small incision was made near the distal da Vinci 8‐mm port (Figure 2C–E). After confirming intra‐abdominal access, the caudal distal port was undocked and reinserted (Figure 2F). The pneumoperitoneum was then transferred to the intra‐abdominal cavity, and three 8‐mm ports for the transperitoneal approach were placed. Retargeting is performed, and the procedure transitions to intra‐abdominal manipulation. No repositioning is required. During this process, all da Vinci 8‐mm ports used for the retroperitoneal approach—except the assistant port—are removed. The port removal sites are sutured to prevent pneumoperitoneum leakage. No additional assistant ports were retained. The assistant port remained usable throughout both phases of the procedure. This technique allows safe hilar control via the retroperitoneal approach, followed by nephrectomy via the transperitoneal approach with an adequate field. Port configuration is shown in Figure 1, and preoperative three‐dimensional CT images and representative intraoperative steps are shown in Figure 2. Since hilar vessel management is completed first, adrenal preservation is also facilitated. To evaluate its feasibility, hybrid RARN was performed in two patients with renal cell carcinoma (Table 1), initially in a case with relatively simple hilar anatomy and subsequently in a deferred cytoreductive nephrectomy after TKI–IO therapy.

FIGURE 2.

Preoperative three‐dimensional CT images and representative intraoperative views of hybrid robot‐assisted radical nephrectomy. (A, B) Preoperative three‐dimensional CT reconstructions of Cases 1 and 2 shown in anterior (left) and posterior (right) views. Green: Tumor; red: Renal artery; blue: Renal vein. (C, D) Dissection and vascular control of the renal artery and vein via the retroperitoneal approach. (E–G) Creation of a small peritoneal incision adjacent to the most caudal retroperitoneal port (■ in Figure 1) to access the intraperitoneal cavity. (H) Placement of the transperitoneal robotic port and transition to the transperitoneal approach.

FIGURE 1.

Port placement for hybrid robot‐assisted radical nephrectomy (Hybrid RARN) on the left side. Port layout: 〇 8‐mm robotic camera port; □ 8‐mm robotic instrument ports; ■ shared 8‐mm robotic port used for both approaches; △ 12‐mm assistant port. A minimum spacing of approximately 4 cm was maintained between ports. (A) Port configuration for the retroperitoneal approach. (B) Port configuration after intraperitoneal conversion for the transperitoneal approach. Image credit: Takayuki Ohzeki.

TABLE 1.

Perioperative characteristics and outcomes of hybrid robot‐assisted radical nephrectomy for renal cell carcinoma.

Variable	Case 1	Case 2
Age/sex	Man	Man
Body mass index (kg/m2)	25.1	20.7
Side	Left	Left
Distant metastasis	None	Lung
Preoperative systemic therapy	No	Yes
Tumor size (maximum diameter, mm)	38	42
R.E.N.A.L Nephrometry Score	11ah	9a
Console time
Retroperitoneal phase (min)	59	39
Transperitoneal phase (min)	33	41
Total console time (min)	92	80
Total operative time (min)	155	137
Estimated blood loss (mL)	57	10
Intraoperative complications	None	None
Histological subtype	Clear cell renal cell carcinoma	Clear cell renal cell carcinoma
Postoperative complications	None	None
Length of hospital stay (days)	8	6
30‐day readmission	None	None

Note: This table summarizes perioperative data for patients undergoing hybrid robot‐assisted radical nephrectomy, including demographics, tumor features, surgical metrics, and postoperative outcomes.

3. Results

Two patients underwent hybrid RARN. The hybrid approach enabled efficient management of the renal hilum via the retroperitoneal route, followed by nephrectomy with an adequate field via the transperitoneal approach. All procedures were completed robotically. Operative time, console time, and blood loss were within acceptable ranges compared with reported single‐approach RARN [10, 11], and no major perioperative complications were observed. There were no readmissions within 30 days of discharge (Table 1).

4. Discussion

Over the decade, indications for robot‐assisted radical nephrectomy (RARN) have expanded due to its minimally invasive nature. It is increasingly applied in challenging settings, including large tumors, locally advanced disease, hilar tumors, and cases following preoperative systemic therapy [4]. Patients treated with immune checkpoint inhibitors or targeted agents often exhibit inflammation and fibrosis, which may obscure tissue planes and complicate dissection [5]. Previous studies have shown nephrectomy after systemic therapy is associated with surgical‐site inflammation and perirenal fibrosis, resulting in technically demanding surgery, with a reported 30‐day complication rate of approximately 30% [5].

Although single‐approach RARN remains the standard, safe dissection and control of major hilar vessels can be challenging in selected cases, particularly those with suspected hilar involvement. The hybrid approach described here was designed to address these issues by integrating the advantages of retroperitoneal and transperitoneal access. Initial retroperitoneal control of the renal artery and vein enables secure vascular management, followed by transperitoneal nephrectomy with a wider operative field. This intraoperative switching may improve vascular control and procedural flexibility in selected patients, particularly when early hilar control is desirable because of complex vascular anatomy or anticipated perihilar adhesions. Robot‐assisted surgery provides advantages over conventional laparoscopic radical nephrectomy, including a three‐dimensional high‐resolution view and enhanced dexterity [4, 10, 11]. In addition, robotic platforms allow flexible port reconfiguration and adaptation to changes in surgical approach. The intracorporeal transition from retroperitoneal to transperitoneal access, technically demanding in laparoscopy, was performed safely in our cases.

In this report, perioperative outcomes were comparable with previously reported RARN [6, 10, 11], with no complications or prolonged operative time. To our knowledge, no previous reports have described a preplanned hybrid approach with intraoperative switching between retroperitoneal and transperitoneal access.

This approach may also be beneficial in cases with renal vein tumor thrombus. The renal artery can be controlled first via the retroperitoneal approach, followed by safe management of the renal vein via the transperitoneal approach. However, it requires additional ports and careful patient selection and may not be suitable for large tumors with limited retroperitoneal working space. Furthermore, the small sample size limits generalizability, and the learning curve and reproducibility remain unclear. Hybrid RARN combines the strengths of both approaches and may improve hilar control and flexibility. Although limited to two cases, this report demonstrates technical feasibility and provides proof of concept. Further studies are warranted to validate its applicability.

Ethics Statement

This study was approved by the Institutional Review Board of Izumi City General Hospital (approval number: 25J‐14).

Consent

Written informed consent was obtained from all patients.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.