Pelvic lymphoceles are a known adverse outcome following lymphadenectomy during extirpative pelvic urologic surgeries, most notably radical prostatectomy. The incidence of any lymphocele after radical prostatectomy with pelvic lymph node dissection (PLND) varies depending on how they are diagnosed (ie, clinically vs radiographically) and on the defined follow-up interval, with reported rates of 8.4% to 51%. Symptomatic lymphocele, which can be associated with infection and compression of pelvic structures, is seen in 2% to 8% patients after prostatectomy and lymphadenectomy.¹

Lymphocele morbidity is well established and can include severe sequelae such as deep vein thrombosis and sepsis. If lymphatic fluid can be reabsorbed by peritoneal surfaces, then why does an intraperitoneal lymphocele occur after transperitoneal prostatectomy? We believe that lymphocele formation after a transperitoneal procedure with PLND occurs as a result of bladder adherence to the pubic bone and pelvic sidewall. A pocket of lymphatic fluid near the PLND bed is therefore excluded from the rest of the peritoneal cavity. As the lymphatic fluid accumulates within this space, it may be prone to infection or adjacent iliac vein compression. Thinking about it in this way explains why lymphoceles are so rare after radical cystectomy—the bladder is not there to exclude any fluid pockets, allowing lymphatic fluid to be absorbed by the peritoneum.²

When we first conceived of using the peritoneum to prevent this from happening, the key observation was simple: the visceral peritoneum of the bladder exists natively on its posterior surface, but not laterally. If we can affix peritoneum to the bladder’s lateral surface (the part that scars to the pelvic sidewall) it cannot scar to the sidewall and sequester fluid. The peritoneal advancement flap (PAF) deliberately provides the bladder with lateral visceral peritoneum before exiting the case. This technique was nearly identical to the technique we employed when creating a peritoneal window in a patient with a preexisting lymphocele. So, our thought was, why not preemptively create a PAF window in all patients who have PLND?

Available peritoneal surface is rotated, advanced, and interposed between the bladder and the lymphadenectomy bed using a four-point fixation of 3-0 vicryl suture (Figure). With the peritoneum now covering the lateral aspect of the bladder, it can no longer “stick” to the pelvic sidewall due to its unique properties. Lymphatic fluid in that pelvic “gutter” will always have a clear pathway or funnel into the peritoneal cavity where it can be absorbed.

Figure. Scan this QR code for a 7-minute video explaining the peritoneal advancement flap technique.⁴

PAFs have been consistently shown to decrease the rate of lymphocele formation. Initial development of PAFs occurred at Lahey Hospital and Medical Center.² Our retrospective review of 155 patients in 2015 demonstrated that compared to patients undergoing robot-assisted laparoscopic prostatectomy (RALP) without peritoneal flap interposition, in which lymphoceles formed in 9 of 77 (11.6%), not a single patient who had peritoneal interposition developed pelvic lymphoceles after a mean follow-up time of 379 days (P = .003).

Since our initial report, numerous studies have replicated similar results, including randomized control trials (PELYCAN), and meta-analyses. In a recent meta-analysis, patients who underwent PAF at the time of RALP+PLND had lower odds of lymphocele formation compared to their counterparts without flaps (OR 0.82, 95% CI 0.27-1.37).¹ Similarly, performing PAF during RALP+PLND was associated with fewer asymptomatic and symptomatic lymphoceles in the PELYCAN trial.³

The evidence is clear. A properly performed advancement flap either prevents or significantly lowers the risk of symptomatic pelvic lymphoceles. This begs the question: why aren’t all surgeons doing this routinely? The technique required to perform this procedure step is relatively straightforward for robotic surgeons to learn and can take less than 5 minutes to perform with experience. We recommend that surgeons dissect lateral to the obliterated umbilical artery when dropping the bladder. Doing so allows for additional peritoneum to be available for the flap.

Are there downsides? We can answer this anecdotally, as there are 2 theoretical issues worth mentioning. Like most “suture this to that” maneuvers in surgery, if one chooses the peritoneal flap position incorrectly (too medially), by advancing bilateral flaps it is possible to wrap the peritoneum too tightly around the bladder dome, potentially decreasing functional bladder capacity. Second, if the “near” suture fixation near the obliterated umbilical artery is aggressively taken too deeply, ureteral injury might occur. We have never seen this. Lastly, situations which may impede or prohibit this technique include cases of abundant perivesical fat and instances in which the peritoneum is not preserved during the bladder drop (ie, prior laparoscopic hernia repair with mesh).

Due to its established association with decreased lymphocele formation after RALP, its straightforward learning curve, and its negligible impact on surgical time, we agree with the studies calling for the incorporation of PAF into guidelines focused on the surgical management of prostate cancer.^1,3 Have you started doing this for your patients yet?