Advancements in Robot-Assisted Radical Prostatectomy

Each year, nearly 270,000 new cases of prostate cancer are diagnosed in the United States, and prostate cancer continues to be the second leading cause of cancer-related mortality in American males.¹ Surgical treatment of localized prostate cancer remains a key component in the treatment pathway for these patients. Historically, although laparoscopic radical prostatectomy was investigated, it was not widely adopted for multiple reasons, including a challenging learning curve and no significant difference in operating time.² Open radical prostatectomy (ORP) remained the predominant method for treatment of localized prostate cancer until the early 2000s, when the introduction of the da Vinci Surgical platform ushered in the era of robotics.³

Over the course of the past 20 years, various techniques, outcomes, and continued improvements in robot-assisted laparoscopic radical prostatectomy (RALP) have continued to emerge. More recently, the introduction of the da Vinci Single Port (SP) robot has provided further room for innovation and enhancement of the RALP technique.³ Concerns about cost, compared with traditional open radical prostatectomy, seem to have dissipated as several reports have consistently reported RALP to be a cost-effective treatment alternative to its open counterpart.⁴ In this article, we briefly summarize a history of the RALP, its outcomes, and future directions.

Although randomized controlled trials in surgical care are difficult to perform due to their invasive nature, there is some high-level evidence showing an overall favorable profile for RALP compared with ORP. In a phase 3 randomized clinical trial comparing RALP with ORP in Australia, investigators randomized men with localized prostate cancer in a 1:1 ratio to RALP or ORP respectively.⁵ Primary outcomes included sexual function measured by the International Index of Erectile Function (IIEF), urinary function measured by the Expanded Prostate Cancer Index (EPIC), and oncologic outcomes including biochemical recurrence (BCR).

Although RALP and ORP were found to have equivalent urinary and sexual function outcomes, there was a significant difference in rates of BCR in favor of the RALP cohort as compared with ORP despite the RALP cohort having a higher rate of positive surgical margins. Other benefits favoring RALP over ORP include decreased blood loss, shorter length of hospital stay, and an improved postoperative pain profile.²

Robot-Assisted Laparoscopic Radical Prostatectomy Techniques

Various techniques for performing RALP have been described. The most frequently utilized technique for the RALP is the transperitoneal technique described by Menon et al in 2004.⁶ This technique is a derivative of the laparoscopic technique described by the Department of Urology at the Institut Mutaliste Montsouris, Université Pierre et Marie Curie, Paris, France.⁷ Limitations of the traditional transperitoneal technique include the need for steep Trendelenburg positioning, which can pose adverse physiologic challenges, including increased cardiopulmonary stress and increased intracranial pressure.²

Additionally, entry into the peritoneal cavity can lead to bleeding and inflammation from urinary contamination during the procedure. In response to these issues, several authors have described a purely extraperitoneal RALP approach to the procedure; however, the extraperitoneal approach is limited by difficulty in developing the working space and subsequent limited mobility. Both the transperitoneal and extraperitoneal approaches have been shown to be safe and appear to have similar perioperative and oncologic outcomes.⁸ Since the widespread dissemination of these techniques, there have been a variety of modifications posed by various authors to improve patient outcomes with regard to erectile dysfunction, urinary continence, and oncologic outcomes.

An estimated 21% of patients will experience urinary incontinence requiring at least 1 pad per day after prostatectomy²; therefore, urinary continence is component of RALP that many surgeons have sought to improve. One of the most common techniques is referred to as the Rocco stitch,⁹ which is used to reconstruct the posterior aspect of the rhabdosphincter. In the original report, the authors proposed the reconstruction of the “musculofascial plate,” suturing the rhabdosphincter and Denonvilliers fascia to the posterior wall of the bladder prior to performing the vesicourethral anastomosis. The authors reported a 49.2% improvement in urinary continence when performing this modification.⁹ Another modification to improve continence is the retropubic suspension stitch proposed by Patel et al, who reported a 7% improvement in early return to continence (3 months) compared to not applying the stitch.¹⁰

Approaches to Prostatectomy Continence

No discussion of postprostatectomy continence could be complete without mentioning the “Retzius-sparing” RALP (RS-RALP) approach as described by Galfano et al.¹¹ In RS-RALP, surgeons do not violate the space of Retzius; instead, the dissection is carried out posterior to anterior, starting by identifying the seminal vesicles and ending with the separation of the dorsal venous complex.¹¹ The primary proposed benefit is a faster return of urinary continence compared to traditional RALP; however, rates of continence are similar between the techniques after >-3 months. Compared with traditional RALP, there is still concern about the oncologic efficacy of RS-RALP as some authors reported higher rates of positive surgical margins. However, a recent large-scale meta-analysis has proposed no significant difference and no difference in rates of BCR between the 2 techniques.¹²

Erectile dysfunction is a complication of RALP, affecting an estimated 50% to 70% of postprostatectomy patients.² One of the earliest techniques described is preservation of the accessory pudendal artery¹³ during RALP, which the authors reported may assist with return of erectile function in patients with arterial insufficiency. Other modifications, such as preservation of the “Veil of Aphrodite,” have been described and shown to improve erectile dysfunction outcomes, and continue to play a role in modern RALP.¹⁴

More recently, novel techniques for RALP have been described with the introduction of the SP robotic surgery platform. The 3 primary methods reported are extraperitoneal, perineal, and transvesical. Kaouk et al described the perineal approach using a 3-cm perineal incision that showed promising results, including early urinary continence, in a series of 4 patients.¹⁵ The perineal approach may be a useful option for patients with an extensive history of prior abdominal surgery. Desai et al described the feasibility of transvesical RALP in the late 2000s using cadaveric models; however, it took the evolution of the SP platform to bring it to fruition.¹⁶ Kaouk et al reported on a series of 10 patients undergoing SP transvesical RALP with same-day discharge, early return of urinary continence, and a minimal rate of complications.¹⁷ As surgeons continue to push the boundaries of robotic surgery, the invasiveness of RALP will decrease while patient outcomes will continue to improve while simultaneously increasing the number of techniques available in the treatment armamentarium.

Akhil Abraham Saji, MD is a urology resident at New York Medical College / Westchester Medical Center. His interests include urology education and machine learning applications in urologic care. He is a founding and current member of the EMPIRE Urology New York AUA section team.

 

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