Retroperitoneal Robot-Assisted Partial Nephrectomy in Obese Patients

Long term experience of robotic retroperitoneal partial nephrectomy as the default approach in the management of renal masses: should the paradigm shift?

Although retroperitoneal surgery has demonstrated a better quality of recovery compared to transperitoneal routes, Retroperitoneal Robot Assisted Partial Nephrectomy (RRAPN) remains proportionally infrequent. As the boundaries of what is achievable robotically continue to be pushed, we present our experience at a high-volume tertiary referral centre that specialises in retroperitoneal surgery, exploring its feasibility as standard of care in the management of small renal masses. A prospective database of 784 RAPNs (2009-2020) was reviewed and 721 RRAPNs (92%) were performed at our centre. In our practice, we utilise a four-port approach to RRAPN. Patient, tumour and operative characteristics were assessed and both oncological outcomes and trifecta and pentafecta achievements were determined. Pentafecta was defined as achieving trifecta (negative surgical margin, no post-operative complications and WIT of < 25 min) plus over 90% estimated GFR preservation and no CKD stage upgrading at 1 year. Multivariate analysis was conducted to predict peri-operative factors which may prevent achieving a trifecta/pentafecta outcome. From 784 cases, 112 RAPNs were performed for imperative reasons, whilst the remainder were elective. Mean BMI ± s.d amongst our cohort was 28.6 ± 5.7. Mean tumour size was 3.1 cm (range 0.8-10.5 cm) and 47% of cases were stratified as intermediate/high risk using R.E.N.A.L nephrometry scoring. Forty-six patients had lesions in a hilar location, and 31% were anterior. Median blood loss was 30mls, with an open conversion rate of 1% and transfusion rate of 1.6%. Median warm ischaemic time (WIT) was 21 min, positive surgical margins were found in 4% and our post-operative Clavien 3/ > complication rate was 2.6%. We had a 1-day median length of stay with a 30 day readmission rate of 2%. Of 631 patients (80%) with a definitive histological diagnosis of cancer, 23% had T1b/ > disease. Over a mean 15 month follow-up period (range 1-125 months), 2% of patients developed recurrences and our cohort demonstrated a 99% 5 year cancer specific survival. Trifecta was achieved in 67% of cases and pentafecta in 47%. Age (p = 0.05), operative time (p = 0.008), pT1b tumours (p = 0.03), R.E.N.A.L score and blood loss (p = 0.001) were found to statistically significantly influence achievement of trifecta. Pentafecta achievement was influenced by R.E.N.A.L score (p = 0.008), operative time (p = 0.001) and blood loss (p = 0.001). We demonstrate the retroperitoneal approach in RAPN is feasible and safe irrespective of lesion location and complexity. In the hands of high-volume centres that are skilled in the retroperitoneal approach the benefits of retroperitoneal surgery can be extended even to challenging cohorts of patients without compromising their oncological or functional outcomes.

Robot-assisted partial nephrectomy in morbidly obese patients: a VCQI database study

To compare perioperative outcomes following robot-assisted partial nephrectomy (RAPN) in patients with morbid obesity (body mass index (BMI > 40 kg/m2)) and non-obese patients. Using the Vattikuti Collective quality initiative (VCQI) database for RAPN, data for morbidly obese and non-obese patients was obtained. Propensity scores were calculated for two treatment groups (morbidly obese vs. non-obese) for the following variables i.e. age, sex, tumor size, RNS, surgical access (retroperitoneal/transperitoneal) and estimated glomerular filtration rate (eGFR) to ensure comparability. The primary outcome for the study was comparison of trifecta between the two groups. In this study, 158 morbidly obese patients were matched with 158 non-obese patients undergoing RAPN. Two groups matched well for age, sex, tumor size, eGFR and RNS. There was no difference between two groups for ischemia time, blood loss, blood transfusion, conversion to radical nephrectomy, length of stay, intraoperative and postoperative complications. Operative time was longer in morbidly obese patients (median 210 min vs. 120 min, p = 0.000). On pathological analysis, malignant tumors were more likely in the morbidly obese group (83.1% vs.73.4%, p = 0.018). Trifecta outcomes were comparable between the two groups (60.1% vs. 63.3%, p = 0.563). The Median duration of follow-up was 12 months (1-96 months). The morbidly obese group had significantly higher day one creatinine (1.25 ± 0.7 vs. 1.07 ± 0.37, p = 0.001) and significantly lower day one eGFR (62.1 ± 19 vs. 69.2 ± 21, p = 0.018). However, there was no difference between the two groups for the last follow-up creatinine and eGFR. RAPN in morbidly obese patients is associated with equivalent perioperative outcomes compared to non-obese patients.

Transperitoneal Versus Retroperitoneal Robotic-Assisted Partial Nephrectomy in Patients with Obesity

Introduction: We aim to compare transperitoneal (TP) and retroperitoneal (RP) robotic partial nephrectomy (RPN) in obese patients. Obesity and RP fat can complicate RPN, especially in the RP approach where working space is limited. Materials and Methods: Using a multi-institutional database, we analyzed 468 obese patients undergoing RPN for a renal mass (86 [18.38%] RP, 382 [81.62%] TP). Obesity was defined as body mass index ≥30 kg/m2*. A 1:1 propensity score matching was performed adjusting for age, previous abdominal surgery, tumor size, R.E.N.A.L nephrometry score, tumor location, surgical date, and participating centers. Baseline characteristics and perioperative and postoperative data were compared. Results: In the propensity score-matched cohort, 79 (50%) TP patients were matched with 79 (50%) RP patients. The RP group had more posterior tumors (67 [84.81%], RP versus 23 [29.11%], TP; P < .001), while the other baseline characteristics were comparable. Warm ischemia time (interquartile range; 15 [10, 12], RP versus 14 [10, 17] minutes, TP; P = .216), operative time (129 [116, 165], RP versus 130 [95, 180] minutes, TP; P = .687), estimated blood loss (50 [50, 100], RP versus 75 [50, 150] mL, TP; P = .129), length of stay (1 [1, 1], RP versus 1 [1, 2] day, TP; P = .319), and major complication rate (1 [1.27%], RP versus 3 [3.80%], TP; P = .620) were similar. No significant difference was observed in positive surgical margin rate and delta estimated glomerular filtration at follow-up. Conclusion: TP and RP RPN yielded similar perioperative and postoperative outcomes in obese patients. Obesity should not be a factor in determining optimal approach for RPN.

Comparison of perioperative outcomes following transperitoneal versus retroperitoneal robot-assisted partial nephrectomy: a propensity-matched analysis of VCQI database

OBJECTIVE

To compare perioperative outcomes following retroperitoneal robot-assisted partial nephrectomy (RPRAPN) and transperitoneal robot-assisted partial nephrectomy (TPRAPN).

METHODS

With this Vattikuti Collective Quality Initiative (VCQI) database, study propensity scores were calculated according to the surgical access (TPRAPN and RPRAPN) for the following independent variables, i.e., age, sex, side of the surgery, RENAL nephrometry scores (RNS), estimated glomerular filtration rate (eGFR) and serum creatinine. The study's primary outcome was the comparison of trifecta between the two groups.

RESULTS

In this study, 309 patients who underwent RPRAPN were matched with 309 patients who underwent TPRAPN. The two groups matched well for age, sex, tumor side, polar location of the tumor, RNS, preoperative creatinine and eGFR. Operative time and warm ischemia time were significantly shorter with RPRAPN. Intraoperative blood loss and need for blood transfusion were lower with RPRAPN. There was a significantly higher number of intraoperative complications with RPRAPN. However, there was no difference in the two groups for postoperative complications. Trifecta outcomes were better with RPRAPN (70.2% vs. 53%, p < 0.0001) compared to TPRAPN. We noted no significant change in overall results when controlled for tumor location (anteriorly or posteriorly). The surgical approach, tumor size and RNS were identified as independent predictors of trifecta on multivariate analysis.

CONCLUSION

RPRAPN is associated with superior perioperative outcomes in well-selected patients compared to TPRAPN. However, the data for the retroperitoneal approach were contributed by a few centers with greater experience with this technique, thus limiting the generalizability of the results of this study.

Retroperitoneal Robot-Assisted Partial Nephrectomy (rRAPN): Surgical Technique and Review

PURPOSE OF REVIEW

We aim to offer a description of the surgical technique and to review the current state retroperitoneal robot-assisted partial nephrectomy (rRAPN).

RECENT FINDINGS

Partial nephrectomy is the standard treatment for localized kidney tumours. rRAPN is especially useful for kidney tumours of posterior location. It offers advantages such as direct access to the renal artery and no need for bowel mobilization. The disadvantages are the small working space and the less familiar anatomical landmarks. It is a reproducible technique that achieves similar oncological and functional results to the more traditional transperitoneal route (tRAPN). High-quality randomized studies are needed to ascertain the role of new technologies as modern high-flow insufflation systems, intracavitary ultrasound, 3D planning, and augmented reality (AR), in the performance of this operation. rRAPN is especially useful for kidney tumours of posterior location. Robotic surgeons ideally should become familiar with both approaches, transperitoneal or retroperitoneal.

Nephrometry scores: a validation of three systems for peri-operative outcomes in retroperitoneal robot-assisted partial nephrectomy

OBJECTIVE

To externally validate the RENAL, PADUA and SPARE nephrometry scoring systems for use in retroperitoneal robot-assisted partial nephrectomy (RAPN).

MATERIALS AND METHODS

Nephrometry scores were calculated for 322 consecutive patients receiving retroperitoneal RAPN at a tertiary referral centre from 2017. Patients with multiple tumours were excluded. Scores were correlated with peri-operative outcomes, including the trifecta (warm ischaemia time <25 min, no peri-operative complications and a negative surgical margin), both as continuous and categorical variables. Comparisons were performed using Spearman correlation and ability to predict the trifecta was assessed using binomial logistical regression.

RESULTS

All three scoring systems correlated significantly with the main variables (operating time, warm ischaemia time and estimated blood loss), both as continuous and categorical variables. Only PADUA and SPARE were able to predict achievement of the trifecta (PADUA area under the curve [AUC] 0.623, 95% confidence interval [CI] 0.559-0.668; SPARE AUC 0.612, 95% CI 0.548-0.677).

CONCLUSION

This study validates the RENAL, PADUA and SPARE scoring systems to predict key intra-operative outcomes in retroperitoneal RAPN. Only PADUA and SPARE were able to predict achievement of the trifecta. As a simplified version of the PADUA scoring system with comparable outcomes, we recommend using the SPARE system.