Comparison of da Vinci SP and Xi surgical systems for robotic lateral transperitoneal adrenalectomy: a retrospective single-center observational study

Abstract

Purpose

Robotic adrenalectomy was developed to address the limitations of laparoscopic adrenalectomy and enhance the visualization, dexterity, and control of surgeons performing this beneficial minimally invasive technique. This study compared the clinical and perioperative outcomes of lateral transperitoneal adrenalectomy using da Vinci SP and Xi robotic systems (Intuitive Surgical).

Methods

We retrospectively analyzed 84 patients who underwent robotic adrenalectomies at a single institution between January 2019 and July 2024. Sixty-two and 22 patients were treated with da Vinci Xi and SP systems, respectively.

Results

No significant differences in patient demographics, tumor size, or postoperative hospital stay between the 2 groups were observed. The SP system demonstrated significantly shorter operative times for right-sided adrenalectomy (81.0 ± 17.1 minutes vs. 113.3 ± 26.2 minutes, P < 0.001), whereas no significant differences were observed in overall operative time (104.9 ± 28.2 minutes for Xi vs. 93.5 ± 23.2 minutes for SP, P = 0.094) or left adrenalectomy (99.9 ± 28.4 minutes for Xi vs. 104.0 ± 23.0 minutes for SP, P = 0.253).

Conclusion

The da Vinci Xi and SP systems are both effective for robotic adrenalectomy, with the SP system showing particular advantages in right-sided procedures.

INTRODUCTION

With advancements in diagnostic imaging and surgical techniques, incidentally detected adrenal masses are increasingly being diagnosed and surgically resected. Open adrenalectomy is considered the standard traditional surgical approach; however, the advent of minimally invasive techniques led to the first transabdominal lateral laparoscopic adrenalectomy being performed in 1992 [1]. While laparoscopic adrenalectomy has been widely adopted because of its minimally invasive benefits [2,3], several limitations persist, including the 2-dimensional view, rigid instrumentation, and dependence on assistants for camera manipulation. Robotic surgery was developed to overcome these limitations by improving surgeons’ visualization, dexterity, and control [4,5,6,7].

The first robotic adrenalectomy using the multiport da Vinci system (Intuitive Surgical) was reported in Europe in 1999 [8], followed by a second report from the United States in 2000 [9], using the multiport da Vinci S system. This system marked a pivotal shift toward minimally invasive robotic surgery for adrenal conditions. As technology progresses, next-generation multiport systems, including da Vinci X and Xi systems, have expanded the scope of robotic surgery while maintaining the requirement for multiple incisions [10,11,12]. In 2018, the U.S. Food and Drug Administration approved the da Vinci SP robotic system, which initially introduced the potential for single-incision surgeries within urologic applications [13]. Recently, the SP system has also been adopted in adrenalectomy, offering a potentially less invasive approach with promising cosmetic benefits and enhanced technical precision [14,15,16,17].

Despite numerous studies comparing laparoscopic and multiport robotic techniques in adrenalectomy [11,12,18,19], studies specifically examining the SP robotic system remain limited owing to its recent introduction [14,15,16,17]. This is particularly evident for the lateral transperitoneal approach, for which only 2 studies have evaluated SP outcomes [16,17] (Table 1). To address this gap, our study provides a comparative analysis of the SP and Xi robotic systems in lateral transperitoneal adrenalectomy, offering critical insights into the clinical and perioperative outcomes associated with adopting single-port technology in adrenal surgery.

Table 1. Baseline data of studies evaluating SP outcomes in robotic adrenalectomy.

SP, da Vinci SP; TP, transperitoneal approach; RP, retroperitoneal approach.

METHODS

Ethics approval and consent to participate

This retrospective study was approved by the Institutional Review Board of Korea University College of Medicine (No. 2024AS0105), and the requirement for written informed consent was waived by the IRB.

Patients

This retrospective study analyzed the medical records of patients who underwent robotic lateral transperitoneal adrenalectomy using da Vinci SP and Xi systems (Intuitive Surgical) at a single institution between January 2019 and July 2024. Eighty-four patients met the inclusion criteria, with 62 patients treated using the da Vinci Xi system (Xi group) and 22 patients treated using the da Vinci SP system (SP group). The selection of the robotic system for each procedure was based on its availability on the day of surgery.

Surgical procedures

For both Xi and SP adrenalectomies, the patients were positioned in a lateral decubitus position with the contralateral flank of the targeted adrenal gland flexed maximally to optimize surgical access and exposure. Foam padding was used to protect the patients at the pressure points. In the Xi group, a 2.0 cm-sized incision was made along the lateral border of the rectus abdominis muscle at the umbilical level and a glove port was positioned. An 8-mm camera port was introduced through a glove port. For left adrenalectomies, an 8-mm working port was positioned along the anterior axillary line at the level of the upper margin of the rectus muscle. Another working port was placed at the midline of the epigastric region, below the rib margin. To ensure efficient movement of the robotic arms, all trocars were inserted at least at a 2-finger distance from the subcostal margin, maintaining a minimum distance of 8 cm between the robotic trocars to prevent instrument collision. For right adrenalectomies, 3 symmetrically aligned ports were used, along with an additional 8 mm-working port positioned below the xiphoid process to facilitate liver retraction (Fig. 1A). Details regarding this technique were more thoroughly described in a previous study [20]. In the SP group, a 2.5–3.0 cm single incision was made along the lateral border of the rectus abdominis muscle on the targeted side. The incision was positioned above the umbilical line to account for the shorter length of the SP system instruments and to facilitate easier access. A glove port was used as the single-port entry, allowing the insertion of the robotic camera and the necessary instruments (Fig. 1B).

Fig. 1. Port arrangements for left adrenalectomy using the da Vinci Xi system (A) and right adrenalectomy using the da Vinci SP system (B). A glove port was used as the camera. A glove port was used as the camera port.

For both the Xi and SP systems, we used Maryland bipolar forceps in arm 1, monopolar cautery in arm 2, and Cadiere forceps in arm 3 regardless of the surgical side. The glove port provided the primary access point for the camera and the single port, while also allowing an auxiliary route for additional instruments, such as suction or gauze (Fig. 2A). To optimize intraoperative suction, we used a modified Jackson-Pratt (JP) drain with 3–4 holes at the distal end, which functioned as an effective suction device throughout the procedure (Fig. 2B, C).

Fig. 2. A glove port and a trimmed Jackson-Pratt (JP) drain. (A) A glove port, with multiple access points, serves as an auxiliary route for surgical instruments, including gauze and suction devices. (B, C) A modified JP drain, trimmed to retain 3–4 distal holes, functions as an effective suction device during the procedure.

Following port placement, adrenalectomy was performed according to standard procedural techniques. For left adrenalectomy, the Mattox maneuver was employed to mobilize the descending colon and to expose the retroperitoneal structures, including the adrenal gland. Once the adrenal gland was exposed, the adrenal veins and arteries were sequentially ligated, and the gland was dissected free from the retroperitoneal bed before retrieval using an endopouch. In right adrenalectomies, adrenal gland exposure was achieved by dissecting the lateral edge of the inferior vena cava and mobilizing the liver. The right adrenal vein was precisely ligated and dissection surrounding the adrenal gland was continued until it was completely freed from the retroperitoneal bed. For bilateral vascular ligation, the Xi system employed a vessel sealer extension as the energy device. In contrast, given the lack of energy devices compatible with the SP system, Hem-o-lok clips (Teleflex Medical) were used for vessel ligation.

Statistical analysis

The data used in this study were obtained from the research database of a tertiary medical institution in South Korea. Complications were graded according to the Clavien-Dindo classification. All statistical analyses were performed using IBM SPSS Statistics ver. 25.0 (IBM Corp.). Continuous variables were expressed as means with standard deviations, while categorical variables were presented as percentages. The Student t-test was used to compare continuous variables, and either the chi-square test or Fisher exact test was used for categorical variables. Statistical significance was set at P < 0.05.

RESULTS

Clinicopathological characteristics

The mean age was similar between the Xi (50.9 ± 11.3 years) and SP groups (49.0 ± 11.7 years) (P = 0.526). The body mass index (BMI) was also comparable, with means of 26.6 ± 4.7 kg/m² in the Xi group and 27.5 ± 5.1 kg/m² in the SP group (P = 0.413). Tumor size was consistent across groups, with an average of 3.3 ± 1.7 cm in the Xi group and 3.3 ± 1.3 cm in the SP group (P = 0.240). Sex distribution was balanced, with males comprising 48.4% of the Xi group and 59.1% of the SP group and females comprising 51.6% and 40.9%, respectively (P = 0.461). The distribution of tumor laterality was also similar, with 37.1% right-sided tumors in the Xi group and 45.5% in the SP group, and with 62.9% and 54.5% left-sided tumors, respectively (P = 0.612).

The distribution of diagnoses did not differ significantly between the groups. In the Xi group, pheochromocytoma was the most common diagnosis (29.0%), followed by primary aldosteronism (25.8%), Cushing disease (22.6%), and nonfunctioning benign tumors (21.0%). In the SP group, Cushing disease was the most frequently diagnosed disease (40.9%), followed by primary aldosteronism (27.3%), pheochromocytoma (18.2%), and nonfunctioning benign tumors (13.6%) (P = 0.520).

The duration of postoperative hospital stay was comparable between the 2 groups, with an average duration of 3.7 ± 1.1 days for the Xi system and 3.6 ± 0.7 days for the SP system (P = 0.922). No significant complications were documented in either group, based on the Clavien-Dindo classification (Table 2).

Table 2. Clinicopathological characteristics of patients.

Values are presented as number only, number (%), or mean ± standard deviation.

Xi, da Vinci Xi; SP, da Vinci SP.

Perioperative parameters

The overall mean operation time was slightly shorter in the SP group (93.5 ± 23.2 minutes) compared with the Xi group (104.9 ± 28.2 minutes), although the difference was not statistically significant (P = 0.094). When analyzed by laterality, right-sided adrenalectomies showed a significant reduction in operative time for the SP group (81.0 ± 17.1 minutes) compared with the Xi group (113.3 ± 26.2 minutes) (P < 0.001). However, no significant difference in operative time was observed for left-sided adrenalectomies (104.0 ± 23.0 minutes for SP vs. 99.9 ± 28.4 minutes for Xi, P = 0.253).

The mean BMI was comparable between the 2 groups (26.6 ± 4.7 kg/m² for Xi vs. 27.5 ± 5.1 kg/m² for SP, P = 0.413). For left-sided adrenalectomies, the BMI was almost identical between the groups (27.2 ± 4.9 kg/m² for Xi vs. 27.2 ± 3.9 kg/m² for SP, P = 0.988). For right-sided adrenalectomies, the BMI was slightly lower in the Xi group (25.5 ± 4.3 kg/m²) than in the SP group (28.0 ± 6.6 kg/m²), but this difference was not statistically significant (P = 0.195).

The tumor size was similar between the groups, with an average of 3.3 ± 1.7 cm in the Xi group and 3.3 ± 1.3 cm in the SP group (P = 0.240). For left-sided adrenalectomies, the mean tumor size was 3.1 ± 1.7 cm in the Xi group and 3.5 ± 1.4 cm in the SP group (P = 0.165). In right-sided adrenalectomies, the average tumor size was 3.5 ± 1.8 cm in the Xi group and 3.1 ± 1.1 cm in the SP group (P = 0.450) (Table 3).

Table 3. Perioperative parameters.

Values are presented as mean ± standard deviation.

DISCUSSION

Incidentally detected adrenal masses have traditionally been managed with open adrenalectomy, which has long been the standard surgical approach [21]. However, the advent of minimally invasive techniques revolutionized the field, with the first transabdominal lateral laparoscopic adrenalectomy reported by Gagner et al. [1] in 1992. The development of robotic surgery further expanded surgical options, and the first robotic adrenalectomy was performed by Raffaelli et al. [8] in 1999 in Europe and by Horgan and Vanuno [9] in 2000 in the United States. Initially, multiport robotic systems were utilized; however, in recent years, the SP system has gained increasing acceptance [15,22,23,24,25]. Due to the advantage of performing surgery in a relatively confined space without interfering with intraabdominal organs, many institutions have adopted the retroperitoneal approach for adrenalectomy [11,19,26]. However, at our institution, laparoscopic adrenalectomy has traditionally been performed using the lateral transperitoneal approach. Therefore, when introducing the SP robotic system, we maintained our existing approach and applied the lateral transperitoneal technique accordingly. This study is significant as it is the first to compare the Xi and SP systems in lateral transperitoneal adrenalectomy using a relatively large patient cohort.

The SP robotic system has several advantages over the Xi system. First, it allows for enhanced maneuverability, enabling the 3 robotic arms to move freely in confined spaces [27]. This benefit is particularly evident in right adrenalectomy, where the robotic camera, in ‘cobra mode,’ functions as a liver retractor (Fig. 3), preventing the liver from dropping and obstructing the surgical view. This eliminates the need for a dedicated retraction arm, allowing all 3 robotic arms to be used simultaneously (Fig. 4). Second, because all 3 arms are visible and controllable, the risk of collision is significantly reduced. Third, the SP system features a ‘customized remote center’ function that enhances procedural safety and comfort. The remote center, which is a fixed pivot point around which the robotic arms rotate, minimizes the risk of patient injury by controlling movement. Although a remote center is typically set at skin level to prevent unintended tissue damage, the use of a glove port can shift this point, potentially compromising safety and comfort. However, the ability of the SP system to adjust the remote center allows it to remain at skin level, even with a glove port, thus ensuring both safety and ergonomic efficiency. These features likely explain the significant difference in operative time for right adrenalectomy between the 2 groups in our study.

Fig. 3. Sagittal view of the da Vinci SP system during right adrenalectomy. The endoscopic camera operates in “cobra mode,” functioning as a liver retractor by elevating the liver. This setup allowed all 3 robotic arms to be freely used beneath the retracted area.

Fig. 4. Surgical views of robotic adrenalectomy procedures. (A) Right adrenalectomy with the Xi system. One arm is typically dedicated as the liver retractor, limiting the operation to two functional arms. (B) Right adrenalectomy with the SP system. All three arms are freely usable throughout the procedure. (C) Left adrenalectomy with the Xi system. Typically, only two arms are utilized to minimize port requirements. (D) Left adrenalectomy with the SP system. All three arms are operated through a single incision.

Although an SP system allows free movement in confined spaces, its range of motion is limited. Consequently, frequent repositioning is necessary for extensive dissection. The Xi system offers a distinct advantage for procedures requiring broader access. In adrenalectomies, particularly in leftsided surgeries, the Mattox maneuver for colon mobilization highlights the limitations of the SP system. This limitation may have contributed to the slightly longer operative time observed for left-sided adrenalectomies using the SP system, although the difference was not statistically significant. Additionally, this limitation helps explain the similar overall operative time for the two systems despite the significantly shorter operative time for right adrenalectomy using the SP system.

Another drawback is the shorter length of the SP system instruments. Initially, at our institution, we performed an incision at the umbilical level, similar to the Xi approach. However, this position was later adjusted to a more cranial position to mitigate the shorter length of the SP system instruments. Furthermore, it is important to note that when only 2 arms are used in the SP system, the camera moves freely. However, limitations arose when all 3 arms were used. During camera repositioning, the 2 arms move with the camera; however, the remaining arm may lose visibility, causing the entire robotic setup to become immobile. Therefore, for left-sided adrenalectomy, using only 2 robotic arms, unless necessary, may help reduce the operative time (Fig. 4). Finally, the absence of an energy device compatible with the SP system makes this procedure more challenging.

Two additional notable features in this study are the glove port and the modified JP drain (Fig. 2). The glove port used in both the Xi and SP systems provides an additional access route around the camera insertion site, enabling the introduction of necessary instruments, such as gauze or suction drains, through a single incision. In particular, it has the advantage of allowing the insertion of gauze of various sizes without being restricted by port size. Additionally, when introducing an additional suction device, it was often necessary to remove an existing instrument, which added to the procedural complexity. The use of a glove port has helped mitigate some of these inconveniences. Moreover, the modified JP drain effectively performs suction, especially in confined spaces, where it plays a key role in eliminating surgical fog, a common challenge in such environments, thereby contributing to the success of the procedure [28,29]. Compared with traditional rigid plastic suction devices, the modified JP drain offers 2 significant advantages. First, its flexible design allows for unrestricted movement, in contrast to rigid devices, which may impede the surgeon’s motion. Second, silicone is more resistant to thermal injury than plastic, making it less prone to damage from monopolar cautery used during coagulation or dissection.

Our study has several limitations. This retrospective analysis was conducted at a single tertiary center, and the SP model group included a relatively small number of patients. Further randomized prospective studies with larger sample sizes and more balanced group distributions are needed to validate these findings and confirm the observed differences.

In conclusion, both da Vinci Xi and SP models were effective for robotic adrenalectomies. The da Vinci SP model offers a significant advantage in right adrenalectomies and demonstrates a performance equivalent to that of the Xi model in left adrenalectomies.