Adoption of Single-Port Robotic Prostatectomy: Two Alternative Strategies

Introduction

Since 2000, robotic-assisted laparoscopic radical prostatectomy (RALP) has become the most commonly performed surgery in the United States for patients with localized prostate cancer. ¹ Its evolution has witnessed changes in technology and approaches with the aim of improving the procedure to achieve fewer complications and faster patient recovery. ² Moving one step further in the concept of minimally invasive surgery, efforts to reduce the number and size of incisions for laparoscopic or robotic-assisted surgery have identified limitations restricting widespread adoption. ^3,4

In 2018, the FDA cleared the da Vinci single-port (SP) robotic surgical system (Intuitive Surgical, Sunnyvale, CA) as a purpose-built robotic platform designed for SP surgery and to overcome several of the major hindrances encountered in previous attempts to “adapt” prior robotic systems for a single-incision approach. ⁵ However, as with any other novel technology, implementation of the SP robot by new surgeon users requires an adoption strategy to achieve an immediately safe level of proficiency as well as ideally achieve an acceptable level of efficiency. The elected methods during the learning curve may vary from one surgical team to another. with the initial strategy during adoption potentially varying from the eventual, refined technique. ^6,7

We describe two distinct methods for adopting the SP system for RALP by two experienced robotic surgeons (J.D. and R.A.) and evaluate the initial results. Our goal was to determine the feasibility and utility of these different pathways in the adoption of this novel platform to guide other surgeons embarking on use of the SP robot.

Methods

The initial RALP procedures using the SP robot performed by two surgeons (R.A. and J.D.) were reviewed from prospective data collection at two institutions with IRB approval (OH-1066864): MD Anderson Cancer Center (MDA) in Houston, TX and OhioHealth Dublin Methodist Hospital (DMH) in Dublin, OH. Both surgeons had extensive experience with RALP in multiport fashion, exceeding 3000 such procedures before their initial SP procedures.

The two varying adoption strategies are described herein, and the results were separately and retrospectively reviewed by each surgical group (Table 1). The included variables were age, body mass index (BMI), operative time (OT), estimated blood loss (EBL), nerve sparing, lymphadenectomy, length of stay (LOS), and rate of conversion. Pathology data included pathological stage, positive surgical margins (PSM), and positive lymph nodes. Complications were categorized by Clavien-Dindo classification, and readmissions were assessed within the first 90 days postoperatively.

Initial patient selection for SP RALP in an effort to minimize the risks of complications and facilitate adoption varied at the two institutions. The MDA inclusion criteria were BMI <30 kg/m², no previous abdominal surgery, and lower risk cancers to avoid pelvic lymph node dissection (PLND) in the majority of patients. The DMH patients were also selected for BMI <30 kg/m², but lymphadenectomy was routinely performed in all patients and previous surgery (including as extensive as full midline laparotomy) was not an exclusion criterion. In DMH patients, an initial selection for impotent patients or those unconcerned with sexual function was chosen until it could be confirmed whether the quality of nerve sparing with the SP robot would be achievable in patients desiring potency.

Despite the similarities between the multiport and SP systems, key differences in instrument range of motion, strength, and camera manipulation mandated surgeon preparation before the initial procedures. Both surgeons completed training in a cadaver lab setting, with one surgeon (JD) completing standardized on-line modules and dry-lab exercises provided by the manufacturer as well as case observations before his first procedure.

In addition to performance of PLND and nerve sparing, surgical strategy varied by surgeon in terms of port placement, approach, and pneumoperitoneum pressure used as well as in postoperative hospitalization. At MDA, the initial 10 RALP procedures were performed with a multiport robot on standby as a backup in case of malfunctions or if the procedure could not be completed with the SP. The DMH procedures were performed with only the single incision for the SP port with an 8 mm Airseal port (Conmed, Inc., Utica, NY) alongside it through a gel port, whereas MDA procedures were performed with an additional port for an assistant of either 5 or 12 mm in size for suction and retraction as needed.

All DMH procedures were performed transperitoneally. whereas MDA was performed with both transperitoneal (TP) and extraperitoneal (EP) RALP in the initial series. Pneumoperitoneum pressure of 6 mm Hg was used at DMH per routine as is done at DMH in standard, multiport RALP procedures. ⁸ The DMH patients were managed with a previously reported postoperative pathway targeting same-day discharge, ⁹ whereas MDA patients were typically admitted overnight.

Results

The initial 74 consecutive patients with localized prostate cancer who underwent SP-RALP at MDA and DMH (n = 34 and n = 40, respectively) between January and October 2019 were reviewed without exclusions. Patient demographics and cancer characteristics are summarized in Table 2.

Of the 34 MDA patients who underwent SP-RALP, 10 were performed extraperitoneally and 24 were performed transperitoneally. All DMH patients (N = 40) underwent a TP approach. There were no instances of conversion to multiport, open, or laparoscopic surgery at either institution.

Mean OT for MDA patients was 179.9 minutes (range, 123–252 minutes). When stratified by surgical approach, OT was longer in the EP compared with the TP approach (198 ± 34 vs 172 ± 26; p = 0.021). In the DMH group, OT was 173.1 minutes (range, 147–216 minutes). All MDA patients underwent nerve-sparing procedures and 12% underwent PLND; however. at DMH. all patients had PLND and 55% had nerve sparing. Mean EBL was lower in DMH patients compared with MDA patients (68.1 mL range, 25–250 mL and 124.2 mL range, 50–300 mL) without being clinically significant. No patients required transfusion.

Regarding hospital stay, 35 out of 40 (88%) DMH and 2 out of 34 (6%) MDA patients were discharged the same day of the surgery for a mean LOS of 1.1 days (range, 1–2 days) for MDA and 0.12 days (range, 0–1 day) for DMH. In both groups, the most common pathological stage was T₂ and the predominant postoperative Gleason score was 7 (Table 3).

Neither group reported Clavien III-V complications other than two patients at MDA who underwent the EP approach with PLND and required percutaneous drainage of lymphoceles. Only one readmission occurred at either institution (1.3%), which was one patient in the MDA group readmitted for ileus. In the DMH group, one patient was seen in the emergency department for urinary retention after catheter removal.

Discussion

The field of minimally invasive surgery continues to evolve in terms of technological advancements and constant introduction of new techniques. The two institutions and surgical teams in this study designed their own pathways to incorporate a technological advance in their surgical practices. We described two different methodologies for adopting the da Vinci SP surgical system by two experienced surgeons. This study was not intended to be comparative, but rather to show feasibility of adopting SP RALP by either method with immediately favorable results.

In adopting any new surgical procedure, priority should be given to minimizing the risk of complications and patient morbidity during the learning curve. In this regard, patient selection is critical. ¹⁰ In our study, both groups only included patients with BMI <30 kg/m² in their initial experience and made exceptions only after identifying their capacity for larger patients. Obesity can influence OT and physiological parameters during RALP. with reported OT often longer in obese patients with potentially deleterious effects of high BMI on pulmonary function, particularly in steep Trendelenburg position during TP RALP. ^11,12 An additional strategy for patient selection in early procedures to control OT includes selecting for lower-risk cancers to allow omission of lymphadenectomy.

Having a multiport robot on standby is part of the “backup concept” that has been widely used in medicine. ^13,14 The first 10 surgeries of the MDA group had a multiport system available as a backup to prevent the potential need to convert to open or laparoscopic RALP if difficulties were encountered with the SP robot that prevented completion of the procedure. Fortunately, it was never needed, but institutions adopting new robotic technology should contemplate whether this backup is feasible for patient safety or should be considered in preoperative patient counseling and consent.

Both groups placed the SP port cannula through a gelport, utilizing incisions between 30 and 33 mm. Agarwal and colleagues reported a series of 49 SP RALP patients with 48 performed through a 2.5 cm incision without a gelport, but all had one routine lateral 12 mm assistant port (+1). ¹ The MDA group also utilized a lateral assistant port on the right pararectal line to allow assistance with suction and retraction as a method to overcome the learning curve associated with the new robotic system and its inherent limitations. The tradeoffs will be apparent to new users, as a true single-incision technique will require the console surgeon to keep the field dry himself by using a robotically controlled suction catheter whereas using a 5 mm “+1” assistant port allows additional exposure points and assistant-led suction. A 10 or 12 mm “+1” assistant port allows for immediate extraction of lymph node tissue and can facilitate use of larger clips and sutures more easily than through the gel port. For these reasons, a pure single-incision surgery is feasible, but additional ports can be placed during the learning curve or even beyond based on surgeon preference.

The OT and EBL are two variables that have been frequently used to measure progress in the process of learning a new surgical procedure. As was expected, initial reports of SP RALP have shown longer OT than multiport procedures. Both Dobbs and coworkers and Kaouk and coworkers reported a mean OT over 200 minutes in their initial TP cases whereas for the remaining studies OT was <200 minutes, including those with EP and Retzius-sparing approaches. ^5,15 The mean OT reported in a meta-analysis of 110 publications by Novara and colleagues utilizing the standard multiport robot was 152 minutes. ¹⁶ As previously mentioned, EP was performed on 10 cases in the MDA group. Kaouk and coworkers also presented a series of 10 EP RALP by using the SP platform without a +1 port. ¹⁵

One major factor contributing to OT particularly during the learning curve is the limitation of bedside assistance with certain steps of the procedure such as management of the pedicles. In contrast to the multiport technique with assistant-led placement of 10/5 mm clips, the SP technique will prevent the assistant from being able to do this unless a “+1” port is used, or the surgeon will be required to use the robotic clip applier and have to wait for exchanges. Also, the SP robotic instruments are not as strong, such that making pedicle windows before clipping is more difficult such that some have substituted clipping with the use of more cautery/bipolar coagulation.

Despite a minor difference between groups in EBL, both results were in line with other published RALP series with EBL <200 mL. ^1,5,6,15 Based on the literature and our results, neither EBL nor OT seems to be significantly affected by the use of a +1 port since OT even with PLND but without a +1 port has not deviated dramatically (Table 4).

Faster recovery, less postoperative pain, and shorter hospitalizations have been frequently considered as hypothetical benefits using the SP platform. ¹⁷ Reducing LOS through same-day discharge has been part of the pathway developed at DMH since 2016, with all RALP patients offered same-day discharge as an option. ⁹ Use of the SP for RALP increased the rate of same-day discharge, with 88% of patients in the DMH group discharged the day of surgery.

In addition to previously mentioned variables, the severity and rate of complications are additional benchmarks to help evaluate the efficacy of a surgical procedure and surgeon proficiency. In our initial series of SP-RALP at two institutions, there were no Clavien–Dindo grade IV-V complications. Overall, only four patients required unscheduled additional care postoperatively (two lymphoceles and one ileus in the MDA group; one urinary retention in the DMH group). The two patients who developed lymphoceles were EP procedures (undrained but with peritoneal windows), which may be a risk factor for lymphocele formation after RALP. ¹⁸ The current MDA technique now leaves a drain for EP cases. Although oncologic safety will require longer-term follow-up, the surgical margin rate is comparable to a large series of standard RALP. The higher rate of pT₃, Gleason score 8 to 10, and PSM found in the DMH group are likely related to patient selection criteria since patients were not excluded based on the need for PLND.

There are as yet no rules nor standardized methodologies for the adoption of new surgical procedures in the field of urology by established surgeons. ¹⁹ It may be possible that the optimal strategy is inherent to each individual surgeon or surgical group. Regardless of the process, it is critical to preserve patient safety and ensure reasonable outcomes. This study reports two different pathways used by two experienced RALP surgeons that achieved good results, but other methods are certainly possible as well. Each surgeon should select his/her initial patients and implement safety measures and learning processes based on their surgical experience, knowledge, and available resources, including in the preclinical stage with cadaver or dry lab training to acquaint with the new technology and hone the skills needed in early cases. ²⁰ Multi-institutional series with multiple experienced robotic surgeons adopting the SP system would likely provide further options for new or less experienced surgeons who decide to embark on SP surgery.

There are several limitations in our study, including its retrospective design and the selection bias related to the selection criteria used for the initial patients. However, these strict selection criteria were applied in an effort to reduce the risk of complications during adoption of this novel technology. Another criticism we acknowledge is the relatively short-term follow-up, although the aim of this initial experience focused on immediate outcomes and complications within a 90-day window postoperatively. Additional studies with longer follow-up will ultimately be necessary to evaluate the long-term oncologic and functional outcomes utilizing the SP platform.

Conclusions

Successful adoption of a novel SP robotic surgical system was achieved by two different experienced robotic surgeons using two different strategies with a very low complication rate. The outcomes were similar between groups and comparable with the existing multiport literature, suggesting that the adoption of the SP system may be safely achieved by applying different methodologies.