Modified three-arm port configuration for single-position, single-docking robotic nephroureterectomy: perioperative and oncological outcomes

Abstract

Background

Robot-assisted nephroureterectomy (RANU) often requires intraoperative repositioning. Standard single-docking techniques use a four-arm port layout, which may not be optimal for patients with smaller body habitus. Therefore, this study aimed to evaluate the feasibility and safety of a modified three-arm port configuration for single-position, single-docking RANU.

Methods

We retrospectively analyzed 10 consecutive patients with upper tract urothelial carcinoma (UTUC) who underwent RANU using this modified configuration at a single center (Oct 2023–Oct 2024). The procedure was performed with the Da Vinci Xi system, utilizing a three-arm triangular port placement designed to minimize robotic arm collision. The affected kidney, entire ureter, and bladder cuff were excised en bloc.

Results

All procedures were completed successfully without repositioning or conversion. Mean operative time was 218 min (range, 170–290 min). The mean postoperative hemoglobin decrease was 9.3 g/L (range, 1–19 g/L). The average postoperative hospital stay was 8.7 days (range, 6–10 days). One patient (10%) had a Clavien-Dindo grade I complication (lymphatic leakage). All surgical margins were negative. Pathological stages were pT1 (30%), pT2 (60%), and pT3 (10%). At a median follow-up of 9.5 months, 1 patient (10%) experienced bladder recurrence.

Conclusions

The modified three-arm port configuration appears to be a feasible and safe approach for single-docking RANU, particularly suited to patients with smaller body frames. It demonstrates satisfactory perioperative and initial oncological outcomes in this preliminary series. Furthermore, the three-arm technique may potentially reduce operative costs. This technique may offer a practical minimally invasive option for UTUC, though validation in larger cohorts is warranted.

Highlight box.

Key findings

• In this series, single-position, single-docking robot-assisted nephroureterectomy (RANU) was performed using a modified three-arm port configuration. The technique was designed with consideration for anatomical dimensions common in Asian populations and was associated with successful completion of all cases, negative surgical margins, and an acceptable perioperative safety profile.

What is known and what is new?

• Single-docking RANU using a four-arm port configuration has been established as a feasible approach.

• This report describes a modified three-arm port configuration, outlining its specific placement rationale and presenting initial perioperative outcomes from its application in a consecutive patient series.

What is the implication, and what should change now?

• The findings from this preliminary experience suggest that a three-arm configuration can be used to complete single-docking RANU without repositioning. The described port layout may help mitigate robotic arm collision in patients with a smaller body habitus, indicating that a four-arm setup is not an absolute requirement for this procedure. This approach may also reduce instrument use and associated costs.

• The results support further evaluation of this technique. Larger, comparative studies are warranted to confirm its potential benefits in operative efficiency, cost-effectiveness, and applicability across different patient populations. These findings may inform future technical refinements in robotic surgical approaches to nephroureterectomy.

Introduction

Upper tract urothelial carcinoma (UTUC) is a relatively rare disease, accounting for approximately 5–10% of all urothelial tumors (1). For high-risk, non-metastatic disease, the standard treatment remains radical nephroureterectomy (NU) with excision of the bladder cuff (2). As NU requires access to both the abdominal and pelvic cavities, the traditional open approach involves large incisions and carries significant perioperative morbidity. With benefits including diminished blood loss, shorter hospitalization, and more rapid convalescence, laparoscopic surgery has consequently supplanted open surgery as the preferred option for managing UTUC (3).

In 2006, Rose et al. first reported the use of the Da Vinci system (Intuitive Surgical, Inc., Mountain View, CA, USA) to perform robot-assisted nephroureterectomy (RANU) (4). Since then, many studies have demonstrated the safety and benefits of RANU (5,6). Compared to conventional laparoscopy, the Da Vinci system provides advantages such as threedimensional magnified vision, articulated instruments with tremor filtration, and an ergonomic console. These features enhance surgical precision, which may contribute to improved postoperative outcomes in RANU (7).

Robotic approaches to RANU have evolved along a spectrum of increasing minimal invasiveness. The procedure can be performed using traditional multi-port configurations, which may require intraoperative repositioning or re-docking (8). Efforts to streamline the workflow have led to the development of single-position techniques, primarily utilizing four-arm linear layouts, which aim to reduce operative time and complexity. Concurrently, the emerging single‑port (SP) robotic platform represents the latest technical advance. Compared with multiport systems, it offers potential advantages including a smaller incision, improved cosmesis, reduced surgical trauma, less postoperative pain, and faster recovery (9).

However, we found the four-arm linear layout unsuitable for the average body habitus of Asian patients, as the close proximity of the ports may hinder the movement of the robotic arms, interfering with intraoperative maneuvers. In addition, this linear four‑arm layout often necessitates camera‑port switching and subsequent redocking when shifting the surgical focus from the renal region to the pelvis (10). To address these challenges, we optimized the port configuration based on the average body type of Asian populations and adopted a modified three-arm robotic approach to perform single-position, single-docking RANU. This approach eliminates the need for intraoperative patient repositioning or re-docking of the robotic system and has achieved favorable surgical outcomes. We present this article in accordance with the AME Case Series and SUPER reporting checklists (available at https://tau.amegroups.com/article/view/10.21037/tau-2025-707/rc).

Methods

Study population

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Institutional Ethics Board of Tianjin Nankai Hospital (No. NKYY_YXKT_IRB_2025_053_01) and individual consent for this retrospective analysis was waived.

We conducted a retrospective analysis of 10 consecutive, unselected patients who underwent modified single-docking RANU at Tianjin Nankai Hospital, Tianjin Medical University between October 2023 and October 2024. All patients met the standard clinical and oncologic indications for radical NU with bladder cuff excision, and no selection was made based on body habitus or anticipated technical difficulty for inclusion in this technique evaluation. The cohort included 7 male (70%) and 3 female (30%) patients, with a median age of 69.5 years (range, 65–76 years) and a mean body mass index (BMI) of 24.41 kg/m². Tumors were located on the left side in 8 cases (80%) and on the right side in 2 cases (20%). Among these, 6 cases were renal pelvic carcinoma, and 4 cases were ureteral carcinoma, including 2 in the upper ureter, 1 in the mid-ureter, and 1 in the lower ureter (Table 1).

Table 1. Demographics and clinical characteristics.

No.	Sex	Age (years)	BMI (kg/m2)	Tumor side	Tumor location
1	Female	67	26.04	Left	Pelvis
2	Male	68	19.16	Right	Pelvis
3	Male	75	23.88	Left	Pelvis
4	Male	76	28.34	Left	Pelvis
5	Female	70	23.44	Right	Pelvis
6	Female	71	21.76	Left	Pelvis
7	Male	66	27.06	Left	Ureter (upper)
8	Male	65	25.71	Left	Ureter (upper)
9	Male	72	23.41	Left	Ureter (middle)
10	Male	69	25.25	Left	Ureter (lower)

BMI, body mass index.

Inclusion and exclusion criteria

Patients were eligible for this study if they had: (I) preoperative imaging (computed tomography urography, CTU) suggestive of a unilateral renal pelvic or ureteral mass; (II) pathological confirmation of UTUC via preoperative ureteroscopic biopsy or positive urine cytology; (III) clinical stage ≤ T3N0M0; and (IV) elected to undergo robotic-assisted surgery. Exclusion criteria included: (I) evidence of distant metastasis (cM1); (II) concomitant invasive bladder cancer requiring radical cystectomy; (III) severe cardiopulmonary comorbidities precluding general anesthesia or prolonged pneumoperitoneum; and (IV) previous major ipsilateral renal or retroperitoneal surgery.

Surgical procedure

All robotic procedures were performed by the same lead surgeon (X.Z.) using the Da Vinci Xi surgical system, with a consistent operative and nursing team to ensure technical reproducibility. The lead surgeon (X.Z.) had substantial prior experience, having performed over 50 robotic urologic oncology procedures, including standard RANU, before initiating this modified single-docking technique. This experience ensured the team was proficient with the robotic platform and the fundamental steps of the operation. All patients underwent surgery under general anesthesia with endotracheal intubation. A urinary catheter was placed in all cases to allow bladder filling during the procedure if necessary. The surgeries were performed using the Da Vinci Xi surgical system, employing a modified three-arm port configuration.

Positioning

After induction of general anesthesia, the patient was placed in a lateral decubitus position with the healthy side down. The torso was tilted posteriorly by 60–70 degrees. The upper limb on the affected side was positioned close to the body, while the upper limb on the healthy side was positioned at a 90° angle to the torso and secured with an arm board. A lumbar bridge was raised to create a larger operating space. The robotic surgical cart was positioned perpendicular to the patient’s back (Figure 1).

Figure 1.

Patient positioning for robot-assisted nephroureterectomy. The patient is placed in a lateral decubitus position with the healthy side down. The torso is tilted posteriorly at an angle of 60–70° from the horizontal plane (as indicated). A lumbar bridge is elevated to increase the space between the costal margin and iliac crest. The upper limb on the affected side is positioned alongside the body, while the contralateral arm is secured on an arm board. The robotic surgical cart (Da Vinci Xi) is positioned perpendicular to the patient's back at the level of the abdomen.

Port configuration

A modified three-arm port configuration was used. After routine sterilization, a pneumoperitoneum was established using the Veress needle method at a point 2 cm medial to the lateral border of the rectus abdominis muscle on the affected side at the umbilical level. Pneumoperitoneum pressure was maintained at 10–13 mmHg, and an 8 mm port (Port 1) was inserted. The camera was introduced to confirm correct placement within the abdominal cavity and to ensure there were no injuries from the puncture. Under direct visualization, an additional 8 mm port (Port 2) was placed below the costal margin adjacent to the rectus abdominis muscle on the affected side, and another 8 mm port (Port 3) was placed 2 cm lateral to the intersection of the iliac crest level and the rectus abdominis muscle on the affected side. The distance between any two robotic arm ports was maintained at >8 cm.

Two 12-mm assistant ports were placed on the anterior midline, 3 cm cranial and 6 cm caudal to the umbilicus (Figure 2). For right-sided surgeries, a mirrored port configuration was used, and an additional 5 mm port was placed below the xiphoid process to lift the liver. The initial target positioning of the camera was directed at the mid-descending colon. After connecting the Da Vinci robotic arms, curved bipolar forceps (left arm) and monopolar scissors (right arm) were inserted.

Figure 2.

Port configuration for left-sided robotic nephroureterectomy. Key anatomical landmarks are indicated: the umbilicus, costal margin, and iliac crest. The three robotic 8-mm ports are shown: Port 1 (camera port, placed 2 cm medial to the lateral border of the rectus abdominis at the umbilical level), Port 2 (placed subcostally adjacent to the rectus abdominis), and Port 3 (placed 2 cm lateral to the intersection of the iliac crest level and the rectus abdominis). Two 12-mm assistant ports are placed on the anterior midline, 3 cm cranial (A1) and 6 cm caudal (A2) to the umbilicus.

Dissection of the kidney and proximal ureter

After separating adhesions, the colonic ligament was incised, and the colon was mobilized anteriorly. The renal artery and renal vein were dissected, clipped with Hem-o-lock clips, and transected separately. Following the dissection of the kidney, the ureter was further dissected downward to the level of the iliac vessels. For tumors located in the renal pelvis or proximal ureter, the ureter below the tumor was clipped with Hem-o-lock clips before kidney dissection to prevent tumor seeding.

Dissection of the distal ureter and bladder cuff excision

Without repositioning the patient, disconnecting robotic arms, or re-docking, the surgical field was shifted directly to the lower abdomen and pelvic cavity for further procedures. The ureter was dissected along its course toward the bladder. For lower ureteral tumors, the ureter was clamped distal to the tumor at this stage. The bladder was moderately filled, and the distal ureter was elevated to separate the surrounding bladder muscle layer until the cuff-like mucosal and submucosal layers were exposed. After emptying the bladder, a 3-0 absorbable barbed suture was used to stitch and lift the normal bladder wall adjacent to the ureteral orifice. Subsequently, the mucosal and submucosal layers around the ureteral orifice were gradually incised. Using the right robotic arm alternately with scissors and a needle driver, the incision and suturing were performed simultaneously to prevent urine leakage from the bladder. The bladder mucosa surrounding the ureteral orifice was completely excised, followed by closure of the bladder incision with additional reinforcement of the local seromuscular layer (Figure 3).

Figure 3.

Intraoperative steps of robot-assisted laparoscopic bladder cuff excision. (A) Suturing and lifting the normal bladder wall adjacent to the ureteral orifice using a 3-0 absorbable barbed suture. (B) Gradually incise the bladder mucosa surrounding the ureteral orifice. (C) Subsequently, suture the bladder mucosal defect step by step. (D) Complete closure of the bladder incision with additional reinforcement of the local seromuscular layer.

Lymph node dissection

At our center, lymph node dissection was performed only in patients with preoperative imaging findings suggestive of lymph node metastasis or intraoperative suspicion of lymph node involvement.

Specimen retrieval and drainage tube placement

The specimen was retrieved via a pararectus incision. Drainage tubes were routinely placed in the renal fossa and pelvic cavity and were removed 48–72 h postoperatively. The urinary catheter was typically retained for approximately one week.

Adjuvant intravesical chemotherapy

For all patients, adjuvant intravesical chemotherapy was administered on the first postoperative day. A single dose of 40 mg pirarubicin in 50 mL of normal saline was instilled into the bladder via the indwelling urethral catheter, which was clamped for 60 min before release.

Follow-up methods

Patients were followed according to a standardized protocol. Follow-up assessments were scheduled at 3-month intervals for the first 2 years postoperatively, and every 6 months thereafter. Each visit included a clinical examination, routine blood tests (including complete blood count, renal and liver function), urinalysis, urine cytology, cystoscopy, and abdominal ultrasonography. CTU was performed every 6 months for the first 2 years, and annually thereafter. Outcome events were defined as local tumor recurrence (in the operative field or regional lymph nodes), distant metastasis, or tumor-related death.

Statistical analysis

Given the retrospective, descriptive design of this preliminary study with a small sample size (n=10), formal inferential statistical testing was not performed. Continuous variables are presented as mean with range. Categorical variables are presented as counts and percentages. All analyses were performed using Microsoft Excel 2016.

Results

All surgeries were successfully completed without the need for re-docking or repositioning the patient. None of the cases required conversion to open surgery. The mean operative time was 218 min (range, 170–290 min), and the mean postoperative hemoglobin decrease was 9.3 g/L (range, 1–19 g/L). The average postoperative hospital stay was 8.7 days (range, 6–10 days). Postoperative complications were graded according to the Clavien-Dindo classification. Among the 10 patients, 1 (10%) experienced a grade I complication (lymphatic leakage, managed conservatively). No complications of grade II or higher were observed. Pathological examination confirmed negative surgical margins in all cases, with high-grade urothelial carcinoma diagnosed in each specimen. Tumor staging distribution was as follows: pT1 (n=3, 30%), pT2 (n=6, 60%), and pT3 (n=1, 10%) (Table 2).

Table 2. Perioperative data and pathology findings.

No.	Hb decrease (g/L)	Surgery duration (min)	Hospital stays following surgery (d)	Tumor grade	Tumor stage	Postoperative complications	Surgical margin
1	11	220	9	High-grade urothelial carcinoma	T1	No	Negative
2	10	200	10	High-grade urothelial carcinoma	T1	No	Negative
3	1	290	10	High-grade urothelial carcinoma	T1	No	Negative
4	16	240	8	High-grade urothelial carcinoma	T2	No	Negative
5	14	190	10	High-grade urothelial carcinoma	T2	No	Negative
6	1	270	8	High-grade urothelial carcinoma	T3	No	Negative
7	19	170	8	High-grade urothelial carcinoma	T2	No	Negative
8	9	180	9	High-grade urothelial carcinoma	T2	No	Negative
9	7	200	6	High-grade urothelial carcinoma	T2	No	Negative
10	5	220	9	High-grade urothelial carcinoma	T2	Lymphorrhagia	Negative

D, days; Hb, hemoglobin.

Adjuvant intravesical therapy with 40 mg pirarubicin was administered immediately postoperatively. The median follow-up period was 9.5 months (range, 4–16 months), with no 30-day readmissions. One patient (10%) developed bladder recurrence detected by surveillance cystoscopy at 8 months after surgery, which was managed with transurethral resection. Histopathology confirmed recurrent urothelial carcinoma, and the patient subsequently received adjuvant intravesical chemotherapy (Table 3).

Table 3. Follow-up data.

No.	Follow-up (months)	30-day readmission	Recurrence
1	16	No	No
2	14	No	No
3	13	No	No
4	11	No	No
5	9	No	No
6	8	No	Bladder tumor
7	7	No	No
8	5	No	No
9	5	No	No
10	4	No	No

Discussion

UTUC is a relatively rare disease in urology. In recent years, minimally invasive NU techniques, such as laparoscopic surgery and robot-assisted surgery, have become the preferred surgical options for the treatment of UTUC (6). Since the 21st century, RANU has been increasingly applied in clinical practice (11).

Complete NU with bladder cuff excision requires operating across a wide field, from the upper abdomen to the pelvis. This necessitates ample surgical exposure and working space. In Western reports, single‑docking RANU typically employs a fourarm port configuration placed linearly along the lateral rectus border (5,12).

However, the standard linear four-arm layout may be less optimal for patients with a shorter torso, a common morphotype in Asian populations that reduces the absolute vertical distance between the costal margin and the iliac crest. In such cases, the reduced vertical distance can force ports closer than the recommended 5–7 cm (5,13), increasing the risk of external robotic arm collision. Our modification addresses this by altering the foundational geometry. We replace the linear array with a triangular configuration, increasing the minimum inter-port distance to >8 cm. Moreover, the lines between the camera port (Port 1) and the two working ports (Ports 2 and 3) form an angle of approximately 120° (Figure 4). This shift from a parallel-vector to a divergent-vector system, coupled with a 60–70° posterior tilted position (versus a full lateral decubitus), better utilizes the abdominal width. It expands the effective working envelope and minimizes instrument conflict, thereby enabling a seamless single-docking procedure across the extended surgical field.

Figure 4.

Schematic comparison of port configurations for robotic nephroureterectomy. (A) Conventional linear four-arm layout. (B) Modified triangular three-arm layout. In the conventional approach (A), four 8-mm ports are placed in a straight line along the lateral border of the rectus abdominis muscle, with inter-port distances typically around 5–7 cm. The patient is positioned in full lateral decubitus. In the modified approach (B), three 8 mm ports are arranged in a triangular configuration, with an inter-port distance >8 cm. Moreover, the lines between the camera port (Port 1) and the two working ports (Ports 2 & 3) form an angle of approximately 120°. The patient is placed in a 60–70° posterior tilted decubitus position.

Therefore, we proposed a modified three-arm port configuration. The advantages of this approach include: (I) Adaptability to body type: the three-arm layout is better suited to the shorter average height of Asian populations compared to Western populations, ensuring sufficient spacing between robotic arms to avoid collision or interference during surgery. (II) Optimized port placement: unlike the linear arrangement along the lateral rectus border, this layout is more convenient for performing bladder cuff excision in the deep pelvic region. (III) Potential cost reduction: using one less robotic arm is associated with potential cost savings to some extent.

In recent reports on single-docking RANU, Huang et al. compared perioperative outcomes between RANU and laparoscopic nephroureterectomy (LNU), noting a mean postoperative hospital stay of 8 days for RANU, which is similar to our findings (14). However, their reported intraoperative blood loss was approximately 30 mL, which appears lower than the estimated blood loss corresponding to the mean postoperative hemoglobin drop observed in our cohort. Gabriel et al., in a pooled analysis of 23 multi-port transperitoneal RANU studies, reported a range of operative times from 157 to 326 min, estimated blood loss ranging from 68.9 to 380 mL, and hospital stays between 2.3 and 10.3 days (15). These outcomes align with our own data. Farzat et al. conducted an analysis of 50 patients who underwent RANU, with statistical results indicating one case of positive surgical margin (16). In a multicenter study by Ditonno et al., which included 1,118 patients who received RANU treatment, the postoperative positive surgical margin rate was 4.7% (17). In contrast, none of the 10 patients in our study exhibited positive surgical margins. These variations in perioperative outcomes may be attributable to differences in surgical experience, tumor location and stage, as well as postoperative discharge criteria.

In the past, laparoscopic management of the distal ureter and bladder cuff excision has been challenging (18,19). The complete removal of the ureteral orifice and the subsequent bladder suturing are crucial for reducing postoperative complications and improving patient outcomes. Both intravesical and extravesical approaches have been attempted and applied in laparoscopic surgery, but these methods are technically demanding and have yielded suboptimal results (20). The robotic surgical system has reduced the difficulty of distal ureter and bladder cuff excision, allowing for more precise suturing of the bladder stump (19).

Most researchers performing robotic bladder cuff excision employ the extravesical approach, but evidence is still lacking to establish which method is optimal (21). Some teams use Endo-GIA staplers to excise and close the stump simultaneously, but this increases the risk of secondary stone formation at the stapling site (22).

In our approach, we performed bladder cuff excision using a simultaneous excision-and-suturing technique. This method not only reduces the risk of bladder stump retraction into the deep pelvis, which could potentially prolong the surgery, but also prevents urine leakage from the bladder defect, thus minimizing the risk of intraperitoneal tumor seeding and metastasis. Precisely suturing the bladder defect not only shortens the postoperative indwelling catheterization time and accelerates recovery but also allows for intravesical chemotherapy, which helps reduce the rate of bladder recurrence.

Although switching surgical instruments on the right robotic arm during the procedure may slightly prolong the operative time, it offers greater benefits in ensuring adherence to oncological principles and achieving better surgical outcomes.

This study has several limitations that should be considered. First, its retrospective design and small sample size (n=10) from a single institution limit the generalizability of our findings and preclude robust statistical analysis. Second, while the median follow-up of 9.5 months is sufficient to assess perioperative safety and technical feasibility, it is inadequate to draw definitive conclusions regarding long-term oncological efficacy, such as recurrence-free or overall survival. While our initial results are promising, larger, prospective, and ideally multi-center studies with longer follow-up are needed to validate the safety, efficacy, and broader applicability of this modified port configuration.

Conclusions

The modified three-arm port configuration facilitates successful single-position, single-docking RANU, demonstrating both safety and efficacy. This approach optimizes instrument placement for Asian body morphotypes while minimizing robotic arm collision, enabling a seamless transition between upper abdominal and pelvic surgical fields. Furthermore, the three-arm technique may reduce operative costs compared to conventional four-arm configurations. These advantages support its clinical adoption as a viable minimally invasive option for upper urinary tract urothelial carcinoma.

Supplementary

The article’s supplementary files as

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Institutional Ethics Board of Tianjin Nankai Hospital (No. NKYY_YXKT_IRB_2025_053_01) and individual consent for this retrospective analysis was waived.

Data Sharing Statement

Available at https://tau.amegroups.com/article/view/10.21037/tau-2025-707/dss

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DOI: 10.21037/tau-2025-707