Conversion of Robot-assisted Partial Nephrectomy to Radical Nephrectomy: A Prospective Multi-institutional Study

From sutureless to standard: a comprehensive analysis of conversion rates in laparoscopic partial nephrectomy

OBJECTIVE

To assess the rate at which sutureless partial nephrectomy (SLPN) transitions to standard partial nephrectomy (SPN), focusing on preoperative factors that might prompt such conversions.

PATIENTS AND METHODS

In this retrospective study, we analyzed the efficacy of SLPN performed on adults at our institution from 2016 to 2023. The subjects were patients diagnosed with localized solid renal tumors. The primary technique employed was resection with scissors and argon beam coagulation for hemostasis, with suturing techniques used only when necessary. Predictive factors necessitating conversion to SPN were identified, and the associations among multiple variables were explored using various statistical analysis methods, including logistic regression, to identify key preoperative predictive factors.

RESULTS

Our institution performed 353 SLPN, with 21 cases (5.9%) necessitating conversion to SPN. The conversion rates for the Laparoscopic Partial Nephrectomy (LPN) subgroup and the Robotic-assist Partial Nephrectomy (RPN) subgroup were 7.9% (17/215) and 2.9% (4/138), respectively, nearing statistical significance (P = .066). Significant differences were observed between the conversion group and the no conversion group in terms of preoperative estimated Glomerular Filtration Rate (eGFR), age at surgery, tumor size, and exophytic/endophytic characteristics. Multivariate analysis identified age at surgery, preoperative eGFR, radiological tumor size, and tumor exophytic/endophytic nature as significant predictors for conversion to SPN.

CONCLUSION

This investigation highlights the efficacy and feasibility of SLPN while identifying critical factors influencing the necessity for conversion to SPN. The identified predictors, including younger surgical age, superior preoperative eGFR, and specific tumor characteristics, provide valuable insights for refining surgical strategies.

Nephrometric scoring system: Recent advances and outlooks

A nephrometry scoring system is a key standard to evaluate the feasibility of partial nephrectomy (PN). Whether based on two-dimensional or three-dimensional images, simplicity, effectiveness, and practicality are the keys to the nephrometric scoring system. Since the emergence of RENAL score in 2009, numerous scoring systems based on different anatomical parameters are established to seek accurately and few parameters to assess the risk of PN and complications. This study aimed to achieve a three-game winning streak in PN more easily and efficiently (negative resection margin, maximum preservation of normal nephron function, and avoiding short-term and long-term complications). Using PubMed, we counted 28 kinds of nephrometric scoring systems. We considered only English literatures published and excluded editorials, commentaries, and meeting abstracts. To the best of our knowledge, this is to date and most comprehensive summary as well as an outlook of the nephrometric scoring system.

Development and Validation of a Nomogram Predicting Intraoperative Adverse Events During Robot-assisted Partial Nephrectomy

BACKGROUND

Ability to predict the risk of intraoperative adverse events (IOAEs) for patients undergoing partial nephrectomy (PN) can be of great clinical significance.

OBJECTIVE

To develop and internally validate a preoperative nomogram predicting IOAEs for robot-assisted PN (RAPN).

DESIGN, SETTING, AND PARTICIPANTS

In this observational study, data for demographic, preoperative, and postoperative variables for patients who underwent RAPN were extracted from the Vattikuti Collective Quality Initiative (VCQI) database.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

IOAEs were defined as the occurrence of intraoperative surgical complications, blood transfusion, or conversion to open surgery/radical nephrectomy. Backward stepwise logistic regression analysis was used to identify predictors of IOAEs. The nomogram was validated using bootstrapping, the area under the receiver operating characteristic curve (AUC), and the goodness of fit. Decision curve analysis (DCA) was used to determine the clinical utility of the model.

RESULTS AND LIMITATIONS

Among the 2114 patients in the study cohort, IOAEs were noted in 158 (7.5%). Multivariable analysis identified five variables as independent predictors of IOAEs: RENAL nephrometry score (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.02-1.25); clinical tumor size (OR 1.01, 95% CI 1.001-1.024); PN indication as absolute versus elective (OR 3.9, 95% CI 2.6-5.7) and relative versus elective (OR 4.2, 95% CI 2.2-8); Charlson comorbidity index (OR 1.17, 95% CI 1.05-1.30); and multifocal tumors (OR 8.8, 95% CI 5.4-14.1). A nomogram was developed using these five variables. The model was internally valid on bootstrapping and goodness of fit. The AUC estimated was 0.76 (95% CI 0.72-0.80). DCA revealed that the model was clinically useful at threshold probabilities >5%. Limitations include the lack of external validation and selection bias.

CONCLUSIONS

We developed and internally validated a nomogram predicting IOAEs during RAPN.

PATIENT SUMMARY

We developed a preoperative model than can predict complications that might occur during robotic surgery for partial removal of a kidney. Tests showed that our model is fairly accurate and it could be useful in identifying patients with kidney cancer for whom this type of surgery is suitable.

Factors Affecting Robotic Partial Nephrectomy Conversion to Radical Nephrectomy: A Retrospective Multi-Institutional Analysis in the Michigan Urologic Surgery Improvement Collaborative (MUSIC)

OBJECTIVE

To identify factors related to the conversion of robot-assisted partial nephrectomy (RPN) to robot-assisted radical nephrectomy (RRN) based on data collected by a statewide database in Michigan.

METHODS

Using the Michigan Urological Surgery Improvement Collaborative-Kidney mass: Identifying and Defining Necessary Evaluation and therapY (MUSIC-KIDNEY) database we identified 574 patients for whom RPN was planned. Patient and tumor characteristics were obtained including body mass index (BMI), Charlson comorbidity index (CCI), RENAL nephrometry score, tumor size, and pathologic staging. Treating centers were subdivided by annualized case volume and academic status. Bivariate and multivariate analyses were performed to assess the impact of these factors on the risk of conversion to RRN from RPN.

RESULTS

The conversion rate of RPN to RN was 5.75% (33/574). The difference in RENAL nephrometry score, tumor stage, and size reached statistical significance on bivariate analysis (p<0.001). The tumor stage also reached statistical significance on multivariate analysis [odds ratio (OR); 95%CI (8.97; 3.93-20.48) p<0.001]. The conversion rate was lower among high-volume versus low-volume practices; however, statistical significance was not reached [5.2% (27/520) vs.11% (6/54); p=0.11].

CONCLUSIONS

 Patient factors such as tumor size and renal nephrometry score are likely related to the conversion of RPN to RRN decisions. The data shows that Michigan urologists appear to appropriately assess intra-operative findings and convert to RRN in cases of more advanced kidney tumors. Lower volume centers appear to trend towards a higher conversion rate. Continued quality improvement tracking analysis may further clarify this relationship.

The Influence of Prior Abdominal Surgery on Robot-Assisted Partial Nephrectomy

Background

We evaluated the influence of prior abdominal surgery on perioperative outcomes in patients who underwent robot-assisted partial nephrectomy in initial Japanese series.

Methods

We reviewed patients with small renal tumors who underwent robot-assisted partial nephrectomy from October 2011 to September 2020 at our institution. Patients with prior abdominal surgery were compared with those without prior surgery based on perioperative outcomes. The chi-square test and Mann-Whitney U test were used for statistical analyses of variables.

Results

Of 156 patients who underwent robot-assisted partial nephrectomy, 90 (58%) had no prior abdominal surgery, whereas 66 patients (42%) underwent prior abdominal surgery. No significant differences in perioperative outcomes were observed between with and without prior abdominal surgery groups. In transperitoneal approach robot-assisted partial nephrectomy, 31 patients (80.4%) had prior abdominal surgery. Trocar insertion time in the with prior abdominal surgery group took longer than the without prior abdominal surgery group (32 vs. 28.5 min, P = 0.031). No significant difference was observed in the conversion rate between the two groups (P = 0.556).

Conclusion

Robot-assisted partial nephrectomy appears to be a safe approach for patients with prior abdominal surgery. In transperitoneal approach robot-assisted partial nephrectomy with prior abdominal surgery, trocar insertion time was longer, but no significant differences were found in other outcomes. Transperitoneal approach robot-assisted partial nephrectomy is thus considered a safe procedure for patients with prior abdominal surgery.

Application of IRIS Three-Dimensional Anatomical Models As Preoperative Surgical Planning Tools in the Management of Localized Renal Masses

Introduction: The use of volume-rendered images is gaining popularity in the surgical planning for complex procedures. IRIS™ is an interactive software that delivers three-dimensional (3D) virtual anatomical models. We aimed to evaluate the preoperative clinical utility of IRIS for patients with ≤T2 localized renal tumors who underwent either partial nephrectomy (PN) or radical nephrectomy (RN). Patients and Methods: Six urologists (four faculty and two trainees) reviewed CT scans of 40 cases over 2 study phases, using conventional two-dimensional (2D) CT alone (Phase-I), followed by the CT + IRIS 3D model (Phase-II). After each review, surgeons reported their decision on performing a PN or an RN and rated (Likert scale) their confidence in completing the procedure as well as how the imaging modality influenced specific procedural decisions. Modifications to the choice of procedure and confidence in decisions between both phases were compared for the same surgeon. Concordance between surgeons was also evaluated. Results: A total of 462 reviews were included in the analysis (231 in each phase). In 64% (95% CI: 58-70%) of reviews, surgeons reported that IRIS achieved a better spatial orientation, understanding of the anatomy, and offered additional information compared with 2D CT alone. IRIS impacted the planned procedure in 20% of the reviews (3.5% changed decision from PN to RN and 16.5% changed from RN to PN). In the remaining 80% of reviews, surgeons' confidence increased from 78% (95% CI: 72-84%) with 2D CT, to 87% (95% CI: 82-92%) with IRIS (p = 0.02); this confidence change was more pronounced in cases with a high RENAL score (p = 0.009). In 99% of the reviews, surgeons rated that the IRIS accurately represented the anatomical details of all kidney components. Conclusion: Application of IRIS 3D models could influence the surgical decision-making process and improve surgeons' confidence, especially for robot-assisted management of complex renal tumors.

Outcomes of gasless laparoendoscopic single-port partial nephrectomy in 356 consecutive patients: Feasibility of a clampless and sutureless technique

OBJECTIVES

To investigate the outcomes and feasibilities of gasless laparoendoscopic single-port clampless sutureless partial nephrectomy.

METHODS

We reviewed 356 consecutive patients with primary unilateral non-metastatic renal masses who underwent gasless laparoendoscopic single-port partial nephrectomy (2011-2018), which was performed retroperitoneally using a three-dimensional flexible endoscope, without vascular clamping or renorrhaphy in principle.

RESULTS

The median tumor size was 2.5 cm, and 213 (60%), 105 (29%), and 38 (11%) patients had peripheral, central, and hilar tumors, respectively. Clampless and sutureless partial nephrectomy was accomplished in 337 patients (95%), while eight (2%) and 16 (4%) patients required vascular clamping and renorrhaphy, respectively. The median operative time and blood loss were 220 min and 266 mL, respectively; eight patients (2%) received blood transfusion. Clavien-Dindo grade 3a complications occurred in 27 patients (8%); all these patients had urinary leakage treated with ureteral stent placement, one of whom also developed a postoperative pseudoaneurysm. Among 324 patients diagnosed with renal cell carcinoma, six (2%) had positive surgical margins, and one (0.3%) and seven (2%) developed metastatic and local recurrences, respectively. During a median follow-up of 54 months, no patient died from kidney cancer. The median percent decrease in estimated glomerular filtration rate at 3 months after surgery was 5.7%. No patient experienced postoperative acute renal failure, while one patient with preexisting renal impairment started dialysis at 70 months after surgery.

CONCLUSIONS

Clampless and sutureless partial nephrectomy can be safely accomplished in most patients undergoing gasless laparoendoscopic single-port surgery, yielding favorable oncological and functional outcomes.

Analyzing National Incidences and Predictors of Open Conversion During Minimally Invasive Partial Nephrectomy for cT1 Renal Masses

Objectives: To analyze predictors of open conversion during minimally invasive partial nephrectomy (MIPN) for cT1 renal masses. Methods: The National Cancer Database (NCDB) was investigated for kidney cancer patients who underwent partial nephrectomy (PN) between 2010 and 2015. Patients who underwent MIPN were stratified into converted and nonconverted groups. Sociodemographics, facility characteristics, and surgical outcomes were compared between the two groups, and multivariate logistic regression model was fitted to identify independent predictors of open conversion. Results: In total, 54,246 patients underwent PN for kidney cancer during the 6-year period. Of those, 18,994 (35%) were open partial nephrectomies (OPNs) and 35,252 (64%) were MIPN. Overall, 1010 (2.87%) of MIPNs were converted to OPN. There was an increasing utilization of MIPN from 50.35% in 2010 to 74.73% in 2015. Patients who had open conversion had more 30-day readmissions (5.95% vs 3.31%, p < 0.01). On multivariate analysis; high-volume facility (>30 MIPNs/year), year of surgery (2015 vs 2010), and robotic approach predicted a lower likelihood of conversion (odds ratio [OR] 0.52, confidence interval [CI] 0.44-0.62; OR 0.59, CI 0.47-0.73; and OR 0.31, CI 0.27-0.35; respectively, p < 0.001 for all). Conversely, Medicaid (vs private insurance; OR 1.75, CI 1.39-2.19, p < 0.001) and male sex (OR 1.26, CI 1.11-1.44, p < 0.001) were independent predictors of conversion. Conclusions: Open conversion in MIPN occurred in 2.87% of cases. There was an increasing utilization of MIPN associated with decreased conversion rates. Higher volume hospitals and progressing year of surgery were associated with less likelihood of conversion.

A comparative analysis of various surgical approaches of nephron-sparing surgery and correlation of histopathological grade with RENAL nephrometry score in renal cell carcinoma

Background:

Nephron-sparing surgery (NSS) is the standard of care for small renal masses whenever feasible. This study aims to evaluate the perioperative outcomes of NSS performed by open (open partial nephrectomy [OPN]) or laparoscopic (laparoscopic PN [LPN]) or robotic (robotic PN [RPN]) approach over the past 6 years and to study the correlation of histopathological grade of renal cell carcinoma with the RENAL score.

Materials and Methods:

A retrospective analysis of prospectively collected data of all patients who underwent NSS was done.

Results:

A total of 135 patients underwent NSS. The mean tumour size was 4.4 cm. About 61 patients underwent OPN, 24 had LPN and 50 had RPN. Although tumour size was larger in OPN group (P = 0.01), tumour complexity based on the RENAL score was similar in OPN and RPN groups (P = 0.15). The OPN group had shorter operative time (P = 0.008) but more blood loss (P = 0.001) and length of hospital stay (P = 0.049) as compared to LPN or RPN group. Maximum radiological diameter of tumour (P = 0.017) appeared to be a significant predictor of operative time, while the open surgical approach (P = 0.003) and tumour stage (P = 0.044) were found to be significant predictors of blood loss. Hilar clamping time was similar in OPN and RPN groups (P = 0.054) but higher in LPN group (P = 0.01). However, post-operative decline in renal function (estimated glomerular filtration rate) (P = 0.08) and margin status were comparable among the three groups. The most common histopathology was clear cell carcinoma (70%), and RENAL score was identified as a significant predictor of histopathological grade of tumour (P = 0.008).

Conclusion:

Open, laparoscopic and robotic approaches to PN provide similar patient outcomes. OPN was usually preferred for larger tumours. The post-operative decline in renal functions and complications were comparable among the three approaches. RENAL score correlated significantly with histopathological grade and hence could help in predicting tumour behaviour pre-operatively.