Disclosure: The author uses the Retzius-sparing technique for the majority of robot-assisted laparoscopic prostatectomies.

Approximately 40% of men with newly diagnosed prostate cancer elected curative intent treatment with radical prostatectomy (RP) in 2021. While oncologically effective, RP can be associated with significant urinary and sexual side effects that impact long-term quality of life. Given the excellent prognosis for men treated for localized prostate cancer, reducing the side effects from RP without compromising oncologic outcomes is paramount. Improvements in RP outcomes have gone hand in hand with improvements in the anatomical understanding of male erectile and continence mechanisms.

In 1904 Hugh Hampton Young performed the first radical perineal prostatectomy; 40 years later Millin described the retropubic approach. Both were often used palliatively, for relief of obstructive symptoms. Few men elected for curative intent RP due to the debilitating side effects.

In 1982 Patrick Walsh developed an anatomical approach to RP, incorporating early dorsal venous complex control and neurovascular bundle preservation, which was quickly adopted by urologists, resulting in increased utilization of RP. There were great expectations that the development of minimally invasive techniques, first laparoscopic, then robotic in the early 2000s, would lead to further improvement in functional outcomes. The most common approach to robot-assisted laparoscopic prostatectomy (RALP) used by approximately 90% of surgeons is done anteriorly through the space of Retzius, similar to the open retropubic RP.¹

Post-prostatectomy continence results not just from preservation of the urinary sphincter, but rather from a complex mechanism which incorporates fascial and ligamentous support, blood supply (Santorini plexus, accessory pudendal vessels), the neurovascular bundle, detrusor apron, urethral length, and bladder neck. Because all of these structures are at risk with the classic anterior approach, numerous technical modifications have been incorporated (Rocco stitch, bladder neck preservation) to improve outcomes. However, the 1-year incontinence and erectile dysfunction rates still range from 4%–31% and 10%–46%, respectively, in large meta-analyses.^2,3

An alternative approach, first described in 2010, is the Boccardi or Retzius-sparing (RS) RP, which is similar to the open perineal prostatectomy.⁴ By removing the prostate via a posterior approach through the pouch of Douglas, the support structures which are at risk during the standard anterior approach are left intact (Fig. 1).⁴ Level 1 evidence demonstrates improvement in early return of continence, although the impact beyond 12 months is less clear.⁵ Salvage patients perhaps derive more long-term benefit from the preservation of the additional support structures. In Kowalczyk’s multicenter series 78.4% of RS-RALP vs 43.8% of standard RALP patients were continent (0–1 pads per day).⁶ Positive margin rates were high in both groups, but not statistically different.

Figure 1. View of right prostate during RS-RALP. The seminal vesicles (SV) and vas deferens have been dissected out and the posterior plane above Denonvilliers’ fascia developed to the apex. The neurovascular bundle (NVB) was released posteriorly and then the shoulder developed to define the lateral border of the prostate. The lateral surface was defined from base to apex and joined with the posterior plane, leaving only the right prostatic pedicle. The pedicle is transected sharply using spot monopolar cautery for arterial bleeding. EPF, endopelvic fascia.

However, the unfamiliar anatomical view and technical challenges of the urethrovesical anastomosis result in a steep learning curve which has likely hindered widespread dissemination of the RS-RALP. In addition, there are concerns regarding increased positive margin rates, particularly in pT3 disease, although this may be related to the learning curve.

An alternative technique to RS-RALP recently described by Tewari is the “hood-sparing” approach. Inspired by the work of Robert Myers, this approach preserves the periurethral support structures found in the space of Retzius (Fig. 2) but utilizes the more familiar anterior approach.⁷ In their single-surgeon series, the positive surgical margin rate was 6% and 88% of men were continent (0 pads per day) at 6 weeks, which is comparable to most published RS data.⁷

Figure 2. Sketch demonstrating hood surgical anatomy. Anatomical components of the hood surround and safeguard the membranous urethra and the external urethral sphincter, and thereby urethrovesical anastomosis. 1, pubic symphysis. 2, external urethral sphincter. 3, superficial venous layer. 4, puboperinealis muscle. 5, levator ani muscle. 6, detrusor apron. 7, urethral stump. 8, deep venous complex. 9, neural hammock. 10, vas deferens. 11, retrotrigonal layer. 12, bladder neck. Reprinted with permission.⁷

This leads to the question—does preserving the actual space of Retzius impact outcomes? To determine which periprostatic mechanisms contributed to early continence, Sood et al evaluated 4 different RALP techniques and found that only preservation of the bladder neck impacted early continence return.⁸ Interestingly, patients who underwent a transvesical space of RS (but not bladder neck-sparing) procedure had the worst outcomes.

Avoiding entry into the space of Retzius during RP is probably less important than maximizing periprostatic tissue preservation when striving for early return of urinary continence. The role of tissue preservation was demonstrated by another recent randomized controlled trial which showed that keeping Denonvilliers’ fascia intact led to significantly improved urinary continence at all time points after surgery (immediate continence: 83.3% vs 13.4% in fascial-sparing vs nonsparing).⁹

Does increased tissue preservation impact erectile function? Data from RS-RALP show comparable potency to the standard approach in men who have a full nerve-sparing procedure. However, in Boccardi’s RS-RALP data, 21% of patients with nonnerve-sparing surgery were potent, potentially due to more preservation of neurovascular tissue in the anterior and apical zones.¹⁰

Tissue preservation improves immediate continence—level 1 data support this for RS-RALP. Will this approach become the standard of care? An upcoming clinical trial (NCT05155501) will evaluate the oncologic safety of fascial preservation as well as the functional outcomes and perhaps redefine our standard of care. However, regardless of trial results, the learning curve for RS-RALP may be prohibitive to widespread adoption—27% of RALPs in the U.S. are performed by surgeons doing 2 or fewer per year, and 90% use the anterior approach.¹ However, if similar tissue preservation can be accomplished by incorporating relatively minor changes to a surgeon’s current technique, perhaps we will take another step forward in improving patient outcomes.