Comparison of Single-port Robotic Surgery Using the Da Vinci SP Surgical System and Single-port Laparoscopic Surgery for Benign Indications.

Robot-assisted surgery has rapidly expanded in obstetrics and gynecology in Japan since insurance coverage began in 2018. Although conventional robotic systems use a four-arm, multi-portal approach, the da Vinci SP ® Surgical System, which was designed for single-port surgery, was approved by the Food and Drug Administration in 2018 and introduced to our institution in February 2023, marking its first use in Japan.[ 1 2 ] Single incision laparoscopic surgery (SILS), which was introduced in the late 2000s, has been adopted in various medical fields, including gynecology; however, its limitations such as unstable visualization, restricted workspace, and limited instrument maneuverability have hindered its widespread use.[ 3 ] Our institution began using SILS in 2010, and we have transitioned to incorporating the da Vinci SP ® system. This study aims to compare the surgical outcomes of single-port total laparoscopic hysterectomy (SP-TLH) to those of single-port robot-assisted total hysterectomy (SP-RAH) using the da Vinci SP ® system during its early implementation phase for benign gynecological conditions.

There were no significant differences in patient background data between the SP-RAH and SP-TLH groups [ Table 1 ]. Comparisons of surgical outcomes between the SP-RAH and SP-TLH groups are as follows: Resected uterus weight: 217 (90–500) g versus 256 (100–436) g ( P = 0.06); intraoperative blood loss: 12 (4–147) mL versus 80 (10–780) mL ( P < 0.01); total surgery duration: 199 (131–251) versus 239 (110–282) min ( P < 0.03); pneumoperitoneal surgery duration (endoscopic operation duration): 146 (90–221) versus 186 (110–282) min ( P = 0.03), respectively. The SP-RAH group exhibited significantly lower intraoperative blood loss than the SP-TLH group, and the total operative and pneumoperitoneal surgical durations (intraperitoneal operation duration) were significantly shorter than those in the SP-TLH group. The Hb levels on postoperative days 1 and 3 were 12.7 (6.6–14.7) g/dL and 11.9 (6.5–15.0) g/dL for SP-RAH vs. 11.5 (8.4–13.8) g/dL and 11.6 (7.6–13.3) g/dL for SP-TLH ( P = 0.34 and 0.56, respectively). The WBC counts on postoperative days 1 and 3 were 9.7 (4.4–15.2) 10 3 /μL and 6.0 (3.1–10.7) 10 3 /μL for SP-RAH versus 10.1 (6.2–14.5) 10 3 /μL and 5.6 (3.7–8.8) 10 3 /μL for SP-TLH ( P = 0.23 and 0.21, respectively). The CRP levels on postoperative days 1 and 3 were 2.7 (0.4–11.5) mg/dL and 2.3 (0.2–13.5) mg/dL for SP-RAH versus 4.9 (1.8–8.9) mg/dL and 2.7 (1.0–5.9) mg/dL for SP-TLH ( P < 0.01 and 0.14, respectively). Although CRP levels on postoperative day 1 were significantly lower in the SP-RAH group, there were no significant differences in other parameters measured using postoperative blood samples. No complications of the Clavien–Dindo classification (Grade ≥3) were observed in the two groups, no blood transfusions were performed, and there were no cases of laparotomy [ Table 2 ]. Upon examining the learning curve in terms of surgery duration, we found no decline in SP-TLH during the 1 st year after its introduction, whereas a gradual decline was observed in SP-RAH [ Figure 3 ]. Characteristics and clinical features of patients Data are presented as the mean (range) or n (%). BMI: Body mass index, WBC: White blood cell, SP-RAH: Single-port robot-assisted total hysterectomy, SP-TLH: Single-port total laparoscopic hysterectomy, Hb: Hemoglobin Comparison of surgical outcomes between the robotic surgery and laparoscopic surgery groups Data are presented as the mean (range) or n (%).WBC: White blood cell, CRP: C-reactive protein, SP-RAH: Single-port robot-assisted total hysterectomy, SP-TLH: Single-port total laparoscopic hysterectomy, Hb: Hemoglobin Learning curve comparison between the single-port robot-assisted total hysterectomy and single-port total laparoscopic hysterectomy groups. SP-TLH: Single-port total laparoscopic hysterectomy, SP-RAH: Single-port robot-assisted total hysterectomy

In Japan, SILS was first used in gynecology in the late 2000s following the development of specialized instruments and the growing focus on minimally invasive procedures. Our institution initiated SILS in 2010 and has expanded its application since then. Although SILS is an attractive approach from a cosmetic perspective, the complexity of the procedure due to the limitations on the manipulation of forceps prolongs the procedure.[ 4 5 6 7 ] Thus, this is a high-risk procedure in obese patients and in difficult cases, which means the surgical indications should be carefully handpicked.[ 8 ] Consequently, reports have stated that SILS requires effective training at the time of introduction because of its high burden on the surgeon,[ 9 10 ] who needs to experience at least 30–50 cases before the learning curve stabilizes.[ 11 12 ] At our institution, the learning curve for SP-TLH did not show a decrease in the average surgery duration even after 30 cases, possibly due to the technical complexity and limitations of single-port laparoscopic surgery. Kim et al . underscored that the limited instrument maneuverability and ergonomic challenges in single-port laparoscopic surgery are factors that hinder efficiency improvements even after achieving proficiency.[ 13 ] In contrast, SP-RAH demonstrated stable reductions in the surgery duration after 5–10 cases, highlighting the ergonomic advantages of robotic-assisted surgery. Gupta et al . reported that robotic systems enhance precision, reduce surgeon fatigue, and improve team coordination, which likely contributed to the shorter learning curve observed for SP-RAH.[ 14 ] Furthermore, the conventional da Vinci robotic system has been utilized at our institution since 2012, providing a solid foundation for the smooth adoption of the SP platform that was introduced in 2023. This extensive experience with robotic surgery likely contributed significantly to accelerating the learning curve for SP-RAH. These insights emphasize the importance of institutional expertise in ensuring the successful implementation of new surgical technologies. The da Vinci SP system, which was developed specifically for single-port surgery, has been shown to effectively address the ergonomic and technical challenges of SILS, including narrow working spaces and unstable visualization, as supported by recent studies.[ 14 15 ] To the best of our knowledge, there are only a few reports comparing single-port robotic surgery using the da Vinci SP with single-port laparoscopic surgery. Kim et al . compared single-port robotic surgery using the da Vinci SP with single-port laparoscopic surgery for gynecological procedures such as hysterectomies, myomectomies, and ovarian cystectomies. They reported that robotic hysterectomy (SP-RAH) had a shorter average surgery duration than laparoscopic hysterectomy (SP-TLH); however, the difference was not statistically significant (128.69 ± 50.49 min vs. 114.71 ± 44.20 min; P = 0.134). Moreover, two cases of umbilical hernia were observed in SP-TLH, emphasizing the need to employ single-port approaches cautiously.[ 16 ] However, Kim et al .’s study, which analyzed cases from 2020 to 2022, differs from our initial year of experience with the da Vinci SP system. Their results suggest that the differences in surgery duration between SP-RAH and SP-TLH may decrease as more procedures are performed. As their study included 148 SP-TLH cases, comparing early-phase outcomes might have shown a statistically significant difference in favor of SP-RAH. Therefore, Kim et al .’s findings may not fully reflect our early experience with the da Vinci SP system. Lee and Hong compared laparoscopic surgery with single-port robotic surgery using the da Vinci SP for supracervical hysterectomy and reported that the outcomes were comparable to those of conventional single-port laparoscopy. However, the use of the da Vinci SP system tended to prolong the procedure and exacerbate the patient’s inflammatory response.[ 17 ] Furthermore, Oh et al . compared the da Vinci SP and the conventional da Vinci Xi for sacrocolpopexy and reported that the learning curves of the two techniques did not differ significantly from each other, as both techniques required <15 cases for the surgery duration to stabilize.[ 15 ] A comparison of surgical outcomes between SP-RAH using the da Vinci SP and SP-TLH at this institution showed a significant reduction in blood loss and total surgery duration, and the learning curves also showed that the duration for SP-RAH was significantly shorter than that for SP-TLH. These findings indicate that the da Vinci SP surgical system is easier to operate than SILS and more instrumental in learning and teaching surgical techniques. The outcomes of total hysterectomy for benign gynecological diseases are reported to not differ significantly in terms of surgery duration, intraoperative blood loss, and the incidence of postoperative complications between single-port robotic surgery using the da Vinci SP and multi-port surgery using the da Vinci Xi.[ 18 ] In the future, the use of robotic surgery is expected to expand from conventional to single-port robotic surgery, improving patient satisfaction. With robotic surgery in Japan still in its nascence, single-port robotic surgery is performed in only a few facilities. Since robotic surgery in Japan is still in its early stages, single-port robotic surgery is not performed in many facilities. With growing patient preference for single-port robotic surgery due to its cosmetic and minimally invasive features, the da Vinci SP system is anticipated to gain widespread acceptance as a key modality in minimally invasive surgery, as highlighted by Oh et al .[ 15 ] as a technique for minimally invasive surgery, resolving challenges that were difficult to overcome with single-port laparoscopy. Haruki Nishizawa drafted the article. Hironori Miyamura, Yusuke Mizuno, Akiko Ohwaki, Mayuko Ito, Eiji Nishio, and Haruki Nishizawa performed surgery. All authors read and approved the final version of the manuscript. The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request. There are no conflicts of interest.

In this study, we included 23 patients who underwent SP-RAH for benign diseases within 1 year from March 2023, when the da Vinci SP system was introduced, and 33 patients who underwent SP-TLH for benign diseases within 1 year from January 2011, when the single-port laparoscopic procedure was introduced. In the SP-RAH group, a retractor was inserted through a 25 mm horizontal incision in the umbilicus, and a da Vinci SP access port kit was connected to the same site [ Figure 1 ]. The SP monopolar curved scissors ® or the SP fenestrated bipolar ® were used for tissue incision. In the SP-TLH group, a 25-mm horizontal incision was made in the umbilical region, through which X-Gate ® (Johnson and Johnson), LAP PROPTECTER™ (Hakko Medical; Nagano, Japan), or the E·Z ACCES ™ (Hakko Medical) retractor was placed, and three 5 mm trocars were implanted in the same area. We used a 5 mm flexible camera scope (OLYMPUS; Tokyo, Japan) and a HARMONIC ACE ® or ENDOPATH PROBE PLUSII ® (Johnson and Johnson) for tissue incision [ Figure 2 ]. An adequately experienced surgeon performed the surgical procedure, and the same technique was employed in both groups until the vaginal wall was sutured. Access port placement in the SP-RAH group. A 25-mm incision is made in the umbilicus for an access port, allowing the assistant to operate through the same entry. Docking is simplified, and camera insertion requires careful arm adjustment. (a) Abdominal wall incision, (b) da Vinci SP access port kit, and (c) insertion of an instrument. SP-RAH: Single-port robot-assisted total hysterectomy Access port placement in the SP-TLH group. A 25-mm incision is made in the umbilicus for an access port, and three 5-mm trocars were implanted in the same area. (a) Abdominal wall incision, (b) E·Z ACCESS™ and (c) X-Gate®. SP-TLH: Single-port total laparoscopic hysterectomy Patient background information included age, body mass index, number of pregnancies, parity, history of abdominal surgery, presence or absence of endometriosis, preoperative hemoglobin (Hb) levels, and white blood cell (WBC) counts. Surgical outcomes in both groups were retrospectively compared, and data on the weight of the removed uterus, intraoperative blood loss, total surgery duration, pneumoperitoneal surgery duration (time spent in the abdominal cavity), Hb level, WBC count, postoperative C-reactive protein (CRP) levels (on the first and third postoperative days), length of postoperative hospitalization, the presence or absence of complications (Clavien–Dindo classification: grade ≥3), blood transfusion, and conversion to laparotomy were analyzed. In this study, the overall surgery duration for SP-RAH includes the time required for docking, console operation, and closure. Statistical analyses were performed using the Mann–Whitney U -test and the Chi-squared test. Quantitative data are presented as median values (ranges) or frequencies (percentages), and P < 0.05 was considered statistically significant. This study was conducted in accordance with the Declaration of Helsinki and was approved by the institutional medical research ethics review committee of Fujita Health University (Approval No. HM23-132). Informed consent was obtained from all patients.