In 1992, Schuessler et al. [1
] firstly reported their experience with laparoscopic radical prostatectomy (RP). In 1999, a telerobotic surgical system (the da Vinci Surgical System, InSite Vision Systems, Intuitive Surgical Inc., Mountain View, CA, USA) was introduced, initially intended for cardiac surgery. Binder and Kramer [2
] have shown its feasibility and heralded a new era in minimally invasive surgery by enhancing endoscopic vision and anastomotic suturing [3
]. Less than a decade after its first use, over 80% of RPs were performed with this platform in 2008 in the United States [4
]. In order to achieve the best surgical result, surgeons utilized the custom-built modifications to make laparo-endoscopic single-site radical prostatectomy (LESS-RP) possible. The purpose was not only to improve the aesthetic outlook, but to decrease the morbidity of the operation by decreasing the number and the size of trocars. However, the rigid instrumentation and the need for adaptation to the existing platform make the widespread use of these single-site surgeries difficult. The development of articulated and flexible instruments provided the proper platform for triangulation through a single port incision [5
]. Based on this ‘Y’ principle concept of the second robotic assist single site platform, a new ‘plate spring mechanism’ was introduced. The plate spring unit makes single-site surgery easier without compromising security. However, only a few studies with limited case series were reported due to the complexity of the procedures [5
]. In June 2018, a new robotic platform, the da Vinci Single Port (SP) system (which features multi-articulating instruments and a flexible camera embedded in a single trocar) was approved by the FDA for urologic operations. Several medical centers have begun sharing their initial experience using the SP system in RP [6
]. Despite the potential advantages of the SP system, there are still some concerns regarding use of the SP platform. One major problem is the SP system is still not available in most countries except the United States and Korea. The other problem is the significant fixed and variable costs, including the purchase, maintenance and use of the new system. Dobbs et al. [9
] noted that the robotic surgical platform has led to a dramatic change in the availability and utilization of laparoscopic surgery. It is associated with favorable perioperative outcomes, but significantly greater fixed costs of instrumentation and ongoing equipment expenses. Thus, it may not be as cost-effective as the existing systems. In addition, the wrists in da Vinci SP systems are relatively flabby when holding tissue compared to previous systems, such as Si and Xi. This problem discourages surgeons to perform LESS-RP using the SP system.
In 2017, Mattevi et al. [10
] first reported the robotic LESS-RP performed with the single-site VesPa platform. We started using the da Vinci Single-Site platform in Si systems in November 2015. In our previous study, we needed two additional ports to complete LESS-RP [11
]. After improving some techniques, we want to present our procedures and results of LESS-RP by using the da Vinci Si system. To our knowledge, our study represents the biggest series of robotic LESS-RP in the world to date.
The baseline cohort characteristics and pathological data of all patients are shown in Table 1
. The median age of patients was 68 (IQR 63–71) years. Median BMI was 25 (IQR 23–27) kg/m2
. The median PSA value before operation was 10.7 (IQR 7.9–20.1) ng/mL. The median American Society of Anesthesiologists Physical Status (ASA) score before operation was 2 (IQR 2–3). The median setup time for creating the pre-peritoneal space and port placement was 25 (IQR 18–34) minutes. The median robotic console time was 135 (IQR 110–161) minutes. The Median operation time was 225 (IQR 197–274) minutes. Mean blood loss was 365 (IQR 200–600) mL, although it was mixed with urine. All patients (except one with a rectal injury) were permitted to start oral intake eight hours after surgery, and no patient suffered from post-operative ileus. The median hospital stay was 10 (IQR 7–11) days. Median duration of urinary catheterization was 8 (IQR 7–9) days. The positive tumor resection margin rate was 36% (Table 2
). All 120 patients underwent the planned surgical procedure successfully, and no patient required conversion to open surgery or a traditional robotic procedure. The average length of the umbilical scar one year later was 3.1 (IQR 2.6–4.1) cm (Figure 2
). The PSA free-survival rate was 86% at a median 19 months (IQR 6–28) of follow up.
Among the 120 patients, peritoneal rupture occurred when we created the pre-peritoneal space in 41 patients, especially in patients with a history of appendectomy. Most were managed by closing the defect. Overall, peri-operative complications occurred in eleven patients (9.2%) (Clavien-Dindo classification Gr II), including seven patients with peri-operative transfusion and one patient with post-operation pneumonia needing extended antibiotic treatment. Two patients developed lymphocele, managed by drainage for 3 to 4 weeks. One patient had a rectal injury; a 2 cm long rectal laceration was found after prostate resection. This was repaired with two-layer sutures, including primary closure of the rectum and a posterior musculofascial reconstruction after cleaning the rectum with beta-iodine solution and normal saline. This patient received total parenteral nutrition for 1 week before restarting ordinary oral intake. No infection or fistula developed in this patient.
There were 43 (36%) patients who had positive surgical margins. We found that positive margins were more common for patients with biopsy grade group 3 versus grade group 2 (40.8% vs 18.3%, p = 0.007).
We also retrospectively collected 54 patients who underwent traditional multiport robotic RP. Preoperative clinical parameters including age, PSA value and biopsy grade group were similar across the two groups. Operation time and robotic console time for LESS-RP in this study were longer compared to multiport RP (both p
< 0.001). There were no differences in rate of lymph node dissection, length of stay, rate of detectable PSA after RP and incontinence rate (Supplementary Table S1
LESS surgery has been shown to provide the best cosmetic outcomes in many minimally invasive operations in the past two decades. However, in most robotic-assisted RPs, five to six incisions are still needed. In a previous article, we presented our experience of single site plus two additional ports to perform robot-assisted RP (RARP) [13
]. In the past three years, we tried to improve our techniques to use an SP, enabling RARP using a single site with only one additional port.
In more recent studies, RARP using the da Vinci SP platform (SP999) has been reported. Kaouk et al. [6
] presented their initial two RARPS. Gboardi et al. [7
] reported a series of 12 cases. Agarwal et al. [8
] reported a cohort of 49 patients undergoing spRARP. To our knowledge, our study is the largest cohort of single-site RARPs in the world. Moreover, we performed these procedures using the da Vinci Si surgical system, not the modern one (SP system). Even though an older-generation robotic system was used, we achieved very satisfactory results in terms of peri-operative complications, operative time, functional outcomes and cosmetic outcomes.
The key procedure during our initial steps was extraperitoneal space creation. The previous experience of total extraperitoneal herniorrhaphy helped us solve this problem. The mean time for us to set up all the instruments was only 14 min in our recent 30 cases. The other important issue was how to avoid interference between the robotic arms and the assistant’s instruments, such as the suction tube or grasper. The solution was to place the 30-degree scope upwards, which created enough space for the assistant to control those instruments.
The median hospital stay in our study was 10 days, which is much longer than in most series. Patients in Taiwan stay in hospitals longer because of the health insurance policy for cancer patients. The entire admission fee is covered by National Health Insurance, and so the patients pay almost nothing no matter how long they stay in hospital. Patients in our study, therefore, were not discharged home until the Foley catheter had been removed, and they felt they had recovered completely.
The median blood loss was 365 mL in our study, although only 10 patients received blood transfusions during surgery. The amount of blood loss recorded in our study included blood in gauze and the fluid collected via the suction tube. In our initial cases, it took a longer time to complete the operation, so lots of urine was recorded mixed in with the blood lost. We also compared our LESS-RP and traditional multiport methods. Compared to the traditional multiport method, the robotic console time and operation time were much longer (Supplementary Table S1
In this study, the median initial PSA was 10.7 ng/mL, and the positive surgical margin rate was 36.0%, both higher than in the other series. This was because many locally advanced cancer patients were enrolled in our cohort. Kaouk et al. [14
] showed more than 80% of patients with positive surgical margins had high-risk features on final surgical pathology. In our cohort, over 40% of patients had pT3 tumor stage. Though our surgical margin rate was higher than the normal average, we believed this was an acceptable outcome. Due to the same consideration, more than half of the patients underwent lymph node dissection. When comparing biochemical relapse-free survival rates of low-risk patients (with or without lymph node dissection) (Gleason score less than 6, PSA level <10 ng/mL, and clinical stage less than T2a), there were no significant differences in biochemical-free relapse recurrence rates within 10 years of follow up [15
Our procedure provides some benefits over traditional methods. First, we created one additional port in the patient’s right abdomen and placed standard da Vinci endowrist instruments handle by the surgeon’s right hand, which makes all the procedures easy. In addition, this overcomes the issue of needing laparoscopic instruments in close proximity, and the additional port in the patient’s right abdomen will become the entrance for a drainage tube after operation. Secondly, we chose an extraperitoneal approach to avoid bowel injury, and we facilitated early oral intake for patients. Furthermore, the bowel does not interfere with the surgical field, and the degree of head-down tilt (Trendelenburg) positioning was less than for the traditional trans-peritoneal procedure. We also found no post-operative ileus in our cases. Kaouk et al. [14
] showed that the extraperitoneal approach was associated with shorter hospital stay and less pain compared to the transperitoneal approach. Thirdly, the umbilicus is a natural orifice and scar, so a 3 cm curved incision around the umbilicus gives an excellent cosmetic outcome. Since this is implementation of a new approach, the operation time, set up time and robotic console time were notably longer in our first 40 cases. The mean operation time for us from setting up all the instruments to finishing the operation was 176 min in our recent 20 cases. Peritoneal rupture occurred when we created the pre-peritoneal space in 41 patients. Most were managed by closing the defect. The peritoneal rupture rate was 17% in our recent 20 cases. Our study has several limitations. First, this was not a randomized prospective analysis. Particularly, this is a single-arm study, and there is no control, which is a significant shortcoming. Unmeasured confounding due to selection bias is also possible. Second, this is a single-center retrospective review. Subsequent studies to demonstrate the long-term follow-up data are needed. Third, our results showed all men had lower BMI values than those observed in Western reports [8
]. Higher BMI value may increase the surgical risk and mortality.
In our hospital, we performed LESS-RARP successfully by using the da Vinci Si system even though the arm collisions bother the operation sometimes. We believe this procedure will be easier and more feasible by using the da Vinci Xi system because it provides excellent robotic arm movement and minimizes collisions.