Introduction

Figure 1. Robotic radical prostatectomy algorithm. GR indicates grams.

Figure 2. Air docking for robotic simple prostatectomy.

Figure 3. Location of suprapubic incision for transvesical prostatectomy.

Figure 4. Robotic simple prostatectomy algorithm. GR indicates grams.

Figure 5. Air docking for low anterior access.

Figure 6. Low anterior access allows for entry into peritoneal cavity and retroperitoneum.

Figure 7. Robotic partial and radical nephrectomy algorithm. MP indicates multiport; RENAL, radius, exophytic/endophytic, nearness of tumor to collecting system, anterior/posterior, location relative to polar line; SP, single port.

With the advent of the da Vinci Single Port (SP) platform, robotic surgeons now have a new tool in their arsenal to individualize approach in a variety of procedures. The versatility of the SP robot has been demonstrated by numerous surgeons, with descriptions of prostatectomy, partial and radical nephrectomy, reconstructive ureteral procedures, as well as cystectomy, inguinal lymph node dissection, and retroperitoneal lymph node dissection.^1-5 SP has allowed for further regionalization of surgery and reclaiming of spaces that were previously standard areas of surgery for urologists, namely the retroperitoneum and extraperitoneal space.⁶

Currently there are no society-based guidelines on indications for SP vs multiport (MP) robotic platforms. While there has been a robust interest in adopting the former for both facile and challenging cases, for the early career urologist or early SP adopter, navigating the SP system may prove to have a significant learning curve.^7,8 As such, we believe that it is prudent to establish an algorithm on when to perform surgery with the SP platform vs MP, as well as whether to approach the target organ transperitoneally, retro-/extraperitoneally, or transvesically. We describe our decision tree below.

Radical Prostatectomy

There are 2 main factors determining whether to perform MP or SP prostatectomy for prostate cancer: prostate size and risk stratification (Figure 1). For patients with high-risk disease based on AUA guidelines, MRI findings, or higher Gleason scores (Grade Group [GG] 4, Gleason score ≥8), preferentially opt for the traditional MP transperitoneal radical prostatectomy to enable careful dissection of the prostate, but more importantly, to facilitate the appropriate lymph node dissection. Patients with higher-risk disease, regardless of prostate size, merit more radical surgery due to lymphadenectomy, which is more appropriately rendered through the MP transperitoneal approach during this early phase of adoption.

For patients with low- and intermediate-risk disease, prostate size becomes the primary driver for robotic approach. In men with glands smaller than 80 g, the SP extraperitoneal or transvesical approach is appropriate for GG1 and GG2 disease, as the need to perform a lymph node dissection is based on surgeon’s own personal practice patterns, but typically less common. The SP extraperitoneal approach is preferred for GG3 disease to enable lymph node dissection. In men with larger prostate glands (>80 g), a history of prior abdominal surgery dictates SP extraperitoneal approach. In patients with larger glands and no significant prior abdominal surgery, the MP transperitoneal approach is preferred.

Simple Prostatectomy

The SP platform has allowed for direct docking into the bladder for prostate surgery (Figures 2 and 3).⁹ As such, the preferred approach for simple prostatectomy is SP transvesical, reserving the MP transperitoneal approach for patients with very high BMIs or larger prostate sizes (Figure 4). Additionally, for those surgeons starting off with SP, beginning with prostates that have larger intravesical components is recommended for ease of handling with the more delicate SP instruments.

Partial and Radical Nephrectomy

Since the first comparisons of SP and MP partial nephrectomy from SPARC (the Single Port Advanced Research Consortium), uptake of SP for renal surgery has increased tremendously over the last year.¹⁰ As the kidney is a retroperitoneal organ, there has been increased interest in utilizing the SP platform to better exploit this space. There have been numerous described approaches, including the traditional flank approach. However, more recently, a low anterior access (LAA) has been described using multiple acronyms (modified Gibson, SARA, SPAM, STAB). Located where one might find a classic mini Gibson or McBurney incision (Figure 5), the LAA allows flexibility to approach both the peritoneal cavity and the retroperitoneum (Figure 6).

As per the above algorithm (Figure 7), the primary driver dictating approach for renal masses is tumor complexity as well as volume of visceral fat around the kidney. In patients undergoing radical nephrectomy, we uniformly perform the standard MP transperitoneal approach given ease and efficiency. The SP approach, however, has been described for radical nephrectomy as well, particularly for surgeons proficient with the SP platform.¹¹

For partial nephrectomy, we examine tumor complexity using R.E.N.A.L. (for radius, exophytic/endophytic, nearness of tumor to collecting system, anterior/posterior, location relative to polar line) and PADUA (Preoperative Aspects and Dimensions Used for Anatomical Classification) nephrometry scores. If a tumor is determined to be high complexity, then an MP transperitoneal approach is preferred. For low- and intermediate-complexity tumors, the presence of significant visceral or retroperitoneal fat then determines whether SP can be performed. MP is preferred in patients with significant perirenal fat due to stronger axial rigidity of the robotic arms and wider retraction capabilities, as compared to the SP counterparts. In patients with low-/intermediate-complexity tumors with less visceral and retroperitoneal fat, tumor location (anterior or posterior) and history of prior abdominal surgery dictates transperitoneal vs retroperitoneal approach. Although LAA can easily access anterior tumors via a retroperitoneal approach, in the early learning phase the same access for transperitoneal approach is an excellent option. For posterior tumors, the SP retroperitoneal approach is preferred. For anterior tumors with no prior abdominal surgeries, then both SP transperitoneal and retroperitoneal approaches can be performed. For anterior tumors with prior abdominal surgeries, then the SP retroperitoneal approach should be preferentially performed.

While we presented a current algorithm on decision-making for patients between robotic platforms and approaches, these represent our unique practice guidelines more than dogma. There are numerous factors to consider when evaluating a patient with a renal mass, or high-risk prostate cancer, or even a complex ureteral stricture. Our aim is not to find ways to supplant MP with SP. Rather, as the market expands with newer models of the da Vinci robotic platform, or even novel competitor robotic systems, we should be ready to customize the care of our patients utilizing the strengths of all available technologies and the unique clinical characteristics of our patients. Whereas in the past we only had 1 tool to help perform robotic surgery, now looking toward the future there will be a multitude of options that urologists must critically appraise for the well-being of their patients. We hope this paper will serve as a blueprint for early adopters of SP, as well as other robotic platforms, to help them navigate the tumor and patient characteristics that ultimately dictate appropriate surgery.