Pure single‐port retzius‐sparing robot‐assisted radical prostatectomy with the da Vinci SP: Initial experience and technique description

Abstract Objective To assess the feasibility and safety of pure single‐port (SP) retzius‐sparing robot‐assisted radical prostatectomy (RARP) using the da Vinci SP and describe the technique. Materials and Methods From August 2020 to November 2020, data of 10 consecutive patients with localized prostate cancer, who underwent SP retzius‐sparing RARP, were prospectively collected. Patients demographics, intraoperative variables, postoperative complications, early oncological, and functional outcomes were assessed. Results The patients were aged 46–73 years with a body mass index between 20.3 and 27.4 kg/m2. Prostate volumes ranged from 15 to 47.2 ml, with a median (interquartile range, IQR) PSA level of 7.4 (6.2–9.1) ng/ml. All surgeries were successfully completed without conversion. The median (IQR) operative and console time were 106 (101–109) min and 65 (63–68) min, respectively. The median (IQR) blood loss was 125 (50–150) ml, and one Clavien–Dindo grade I complication occurred. At 3 months, nine patients had undetectable PSA levels and all patients were continent. Conclusions Pure SP retzius‐sparing RARP could be safely performed using the da Vinci SP system, with acceptable surgical times and minimal complications. Future research will evaluate the advantages of this technique over the standard multiport robotic surgery.

The da Vinci single-port (SP) Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) is the first purpose-built SP surgical platform; the system utilizes a 12-mm Â 10-mm articulating camera and three 6-mm double-jointed robotic instruments, all inserted through a 25-mm multichannel port. 7 Since the approval of the da Vinci SP by the FDA in 2018, new ways of performing urologic surgery have been explored. 8 In the present study, we demonstrate the technical feasibility of pure SP retzius-sparing RARP using the da Vinci SP; we report on surgical technique, initial experience, and short-term outcomes of our technique.

| Study population
From August 2020 to November 2020, data of 10 consecutive patients who underwent SP retzius-sparing RARP, by a single surgeon (KHR), for clinically localized prostate cancer were prospectively collected in an institutional review board-approved database. All patients underwent multiparametric magnetic resonance imaging (mpMRI) of the pelvis and bone scan for staging. Exclusion criteria for enrolment were preoperative evidence of extracapsular or metastatic disease. Patients with previous prostate and/or abdominal surgery were also excluded.

| Outcomes measures
Baseline characteristics and clinical data of the patients were collected, including age, body mass index (BMI), Charlson comorbidity index (CCI), American Association of Anesthesiologist (ASA) score, prebiopsy PSA level, biopsy International Society of Urological Pathology (ISUP) grade, and clinical stage. Preoperative urinary and sexual function were assessed using the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short-Form questionnaire and Sexual Health Index for Men (SHIM) score, respectively. 9,10 The collected intraoperative data were docking time, console time, urethrovesical anastomosis time, total operating time, estimated blood loss (EBL), complications, blood transfusion, and conversion. Postoperatively, hospitalization time, catheterization time, surgical margins status, pathology ISUP grade, pathology clinical stage, and complications   within 30 days, according to Clavien-Dindo classification, 11 were recorded. Continence was assessed the day of catheter removal, at 1 and 3 months after surgery. Continence was defined as use of no pads or one safety liner per day. 12 PSA was measured at 1 and 3 months after surgery, and biochemical recurrence (BCR) was defined as two consecutive elevations of serum PSA > 0.2 ng/ml, postoperatively.
The primary outcomes of this study were feasibility of the technique in terms of conversion to anterior approach or multiport surgery and patient safety in terms of intraoperative and postoperative complications. Secondary outcomes that were assessed were perioperative, early oncological, and functional outcomes.  Then, the bladder neck is dissected sharply recognizing the circumferential detrusor muscle fibers ( Figure 1D). The anterior dissection is con-

| Study population
The patients' age ranged between 46 and 73 years, the BMI ranged between 20.2 and 27.4 kg/m 2 , and ASA score ranged between 1 and 3. The median (interquartile range, IQR) preoperative PSA level was 7.4 (6.2-9.1) ng/ml. The clinical T stage was cT1 for seven and cT2 for three patients. The detailed demographic and clinical characteristics of the patients are presented in Table 1.    18 reported their initial experience with the da Vinci SP system in radical prostatectomies in a cohort of 49 patients including 7 cases of retzius-sparing approach. However, an additional 12-mm assistant port was used in the right lower quadrant (SP plus one) and a high rate (three out of seven cases) of conversion to anterior approach was noticed. To the best of our knowledge, our study is the first reporting the feasibility and initial results of pure SP retzius-sparing RARP.

| Early oncological and continence outcomes
The da Vinci SP could be easily adopted in retzius-sparing RARP as is an ideal system in working in narrow spaces. Furthermore, the articulating camera adds the benefit of viewing the surgical field from different angles (0 and 30 ), which is useful during posterior dissection and anastomosis. The technical differences between this new system and its multiport predecessors in port placement, docking the robot, instruments, and camera maneuverability did not importantly prolong our operative time, which was consistently below 2 h. An improvement in operative times during the cases was only noticed for the docking time, from 15 min at the initial case to around 5 min after the fifth case. It is worth emphasizing that off-site training of the surgical team and on-site guidance during the initial cases by trained members of Intuitive Surgical are of paramount importance for a successful transition from multiport da Vinci systems to the SP system.
Despite the da Vinci SP being a purpose-built single site system, some drawbacks still exist. The system provides 7 degrees of freedom movements; although with a different mechanism, the Endowrist technology is lacking and a novel elbow has introduced. We acknowledge that the surgeon could face difficulties during suturing due to changes in instruments dynamics and lack of wristed movements. F I G U R E 3 Bent suction tube and clip applier shaft rates of positive surgical margins were found to the initial cases of extraperitoneal SP RARP by the Kaouk's team. 16 Surgeons interested in adopting our technique should carefully select their initial patients to avoid high rates of positive surgical margins during the learning curve.
We observed excellent continence outcomes in our cohort; seven patients were continent immediately after catheter removal, and all patients were continent at 3 months. In our previous series of multiport retzius-sparing RARP, the continence recovery rate at 3 months was 87.8%. 19 Agarwal et al. also reported excellent continence results, where all patients of their cohort who underwent SP retzius-sparing RARP were continent within 1 week of catheter removal. 18 It is our impression that the smaller instruments (6 mm) and the less traction forces applied by the SP robot could have a positive impact on functional results. A recent comparative study between the da Vinci SP and Xi robots for patients undergoing RARP with the anterior approach showed also better continence results for the SP robot, suggesting that difference in continence rates at 45 days between the SP and Xi groups were 11% (95% CI À5.6% to 28%). 20 Our study was not devoid of limitations. We included a small cohort of patients with the primary outcome of our study to be the feasibility and description of the technique. The short-term follow-up is another limitation. The long-term oncologic outcomes and the benefits of the SP over the multiport approach in terms of cosmesis, postoperative pain, and patient recuperation need further research. Lastly, all the procedures in this study were performed by an experienced robotic surgeon in a tertiary hospital and the results maybe are not applicable to novice surgeons.
In conclusion, pure SP retzius-sparing RARP is a feasible approach for the surgical treatment of prostate cancer. The da Vinci SP system could be easily adopted by an experienced surgical team in this skillintensive procedure, in acceptable surgical times, and without compromising patient safety. The advantages and the long-term oncologic and functional outcomes of this approach should be further evaluated by future studies.