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Effect of Peritoneal Fixation (PerFix) on lymphocele formation in robot-assisted radical prostatectomy with pelvic lymphadenectomy: Results of a randomized prospective trial

  • Vladimir Student Jr.,
  • Zbynek Tudos,
  • Zuzana Studentova,
  • Ondrej Cesak,
  • Hana Studentova,
  • Vaclav Repa,
  • Dana Purova,
  • Vladimir Student

Background

Symptomatic lymphoceles present the most common complication of robot-assisted radical prostatectomy (RARP) with extended pelvic lymph node dissection (ePLND). No surgical technique has so far shown success in reducing the incidence rate, but several retrospective studies have shown the beneficial effect of the fixation of the peritoneum.

Objective

To introduce a modification in the technique of fixing the peritoneum to the pubic bone and to confirm whether this intervention reduces the incidence of lymphoceles.

Design, setting, and participants

A prospective randomized (1:1) single-center one-sided blind study was conducted in patients with localized prostate cancer (cT1-2cN0M0) indicated for RARP with ePLND operated between December 2019 and June 2021. In the intervention group, the free flap of the peritoneum was fixed to the pubic bone. In the control group, the peritoneal flap was left free without fixation.

Surgical procedure

In the intervention group, the free flap of the peritoneum was fixed to the pubic bone (PerFix) so that lateral holes were left, allowing drainage of lymph from the pelvis into the abdominal cavity, where it would be resorbed. The iliac vessels and obturator fossa remained uncovered by the peritoneum and the bladder.

Measurements

The primary objective was to evaluate the frequency of symptomatic lymphoceles during follow-up. The secondary endpoints were the radiological presence of lymphoceles on computed tomography of the pelvis carried out 6 wk after surgery, the volume of the lymphoceles, and the degree of severe (Clavien-Dindo ≥3) complications.

Results and limitations

Of the 260 randomized patients, 245 were evaluated in the final analysis—123 in the intervention and 122 in the control group. The median follow-up was 595 d. There were no differences between the groups regarding clinical and pathological variables. The median of 17 nodes removed was the same in both groups (p = 0.961). Symptomatic lymphoceles occurred in 17 patients (6.9%), while in the intervention group these were found in three (2.4%) versus 14 (11.5%) in the control group (p = 0.011). The number of radiologically detected asymptomatic lymphoceles did not differ (p = 0.095). There was no significant difference in lymphocele volume between the two groups (p = 0.118). The rate of serious complications (Clavien 3a and 3b) was 4.8% in the intervention group and 9.1% in the control group (p = 0.587). A multivariate logistic regression model of symptomatic lymphocele occurrence was created with significant factors: body mass index (odds ratio [OR] = 1.1, 95% confidence interval [CI] = [1.03, 1.26], p = 0.012) and intervention (OR = 4.6, 95% CI = [1.28, 16.82], p = 0.02).

Conclusions

Fixation of the peritoneum (PerFix) reduced the incidence of symptomatic lymphoceles in RARP with ePLND. We found no difference in the frequency of asymptomatic lymphocele development. The volume of the detected lymphoceles was similar.

Commented by Prof. Igor Tsaur

Lymphocele formation is one of the most common side effects following radical prostatectomy and pelvic lymphadenectomy, with formation rates ranging from 2 to 60%. Reportedly, the rate is dependent on both patient characteristics (e.g. BMI or nutritional status) and surgical factors (e.g. sealing techniques or extent of lymph node dissection). 

If clinically inapparent, lymphoceles do not necessitate further treatment and might disappear (or in rare cases, persist) in the mid-term. However, lymphoceles are clinically relevant when they become symptomatic with edema of the low extremity, deep venous thrombosis, constipation, voiding dysfunction, abdominal and leg pain, infection, sepsis, or pulmonary embolism. We need to pay attention to and anticipate harmful so-called “symptomatic” lymphoceles.            

At the time of the adoption of robot-assisted radical prostatectomy (RARP), it was debated that lymphocele formation will decrease due to the transperitoneal approach compared to extraperitoneal retropubic prostatectomy. However, peritoneal flap emerging during preparation of the Retzius space in the direction from the abdominal cavity towards the pubic bone is prone to dropping back over the bladder and growing together with neighboring structures, hence closing lymph drainage into peritoneal cavity in the following course. 

Recently, several groups presented strategies during robotic prostatectomy with pelvic lymphadenectomy aimed at preventing the formation of symptomatic lymphoceles (e.g. using clips of gross lymphatics or tissue adhesives, fixation of emerging peritoneal flap to the bladder, musculus rectus abdominis or different points on the pelvic wall). Unfortunately, neither approach could stand prospective or external validation keeping the medical need for effective and time-sparing techniques of lymphocele prevention vital. 

Medical students and collaborators assessed the value of the so-called PerFix technique – fixation of the peritoneal flap to the pubic bone – in a prospective randomised controlled trial of patients with prostate cancer undergoing RARP and extended pelvic lymphadenectomy. The rationale of this technique consists in leaving the lateral space between the flap and iliac vessels, as well as, obturator foramen open; thus, enabling the flow of lymphatic fluid into peritoneal cavity. Bipolar coagulation was used during pelvic lymphadenectomy without clipping. 

In total, 245 patients with equal clinical and pathological variables were finally assessed, while the median of 17 lymph nodes were resected. Symptomatic lymphoceles occurred in 2.4% of the intervention group compared to 11.5% of the control group (in which the peritoneal flap was left as it is). At the same time, the number of asymptomatic lymphoceles (which were radiologically detected by a fixed follow-up protocol such as a CT scan), and lymphocele volume did not differ between the groups. Higher BMI and lack of fixation of the peritoneal flap were independently predictive of the risk of symptomatic lymphocele formation.

Even if not all presumable risk factors for lymphocele development such as nutritional status, hypoproteinemia, or preoperative use of anticoagulants have been evaluated as baseline characteristics in this study, the results represent one of the first prospective data supporting the fact that peritoneal flap might be the main cause for this adverse sequala. If this feasible technique will be confirmed by external validation, it has a chance to be incorporated in the clinical routine of RARP with pelvic lymphadenectomy. 

The question for future research is whether combination of peritoneum fixation to the pubic bone with clipping of larger lymphatic vessels might further reduce the risk of symptomatic lymphoceles.