Identifying Preoperative Predictors of Operative Time and Their Impact on Outcomes in Robot-Assisted Partial Nephrectomy.

Objective: To identify preoperative characteristics in patients with renal masses that influence operative time during robot-assisted partial nephrectomy (RAPN) and evaluate the relationship between operative time and length of stay (LOS), complication rates, and overall outcome. Materials and Methods: We queried our institutional database to identify a cohort of patients who underwent RAPN by two experienced robotic surgeons between 2012 and 2019. A multivariable regression model was developed to analyze operative time, LOS, and any grade complication within 30 days postoperatively using the bootstrap resampling technique. Results: A total of 392 patients were included. On multivariable analyses, prior abdominal surgery (p = 0.001) was associated with 22 minutes of increase in operating room time, as well as adhesive perirenal fat (22 minutes, p = 0.001). For each one unit increase in nephrometry score, there was a 4-minute increase in operating room time (p = 0.028), and for each one-cm increase in tumor size, there was an associated 12-minute increase in operating room time (p < 0.001). For each 1 year increase in age, there was an associated 0.024-day increase in LOS [odds ratio (OR) (0.013-0.035)]; in addition, for every one-cm increase in tumor size there was a 0.18-day associated increase in LOS [OR (0.070-0.28)]. Each 1-hour increase in operating room time was associated with a 0.25-day increased LOS [OR (0.092-0.41)]. Only tumor size was found to be associated with any grade complication. Conclusions: Patients with a history of abdominal surgery, larger complex tumors, and significant Gerota's fat undergoing robotic partial nephrectomy should anticipate longer operative times. Older patients with larger tumors and longer operative times can anticipate a longer LOS. Tumor size appears to be the common determinant of all three outcomes: operative time, LOS, and any grade Clavien complication.

Effect of delayed resection after initial surveillance and tumor growth rate on final surgical pathology in patients with small renal masses (SRMs).

OBJECTIVE: To understand potential harms associated with delaying resection of small renal masses (SRMs) in patients ultimately treated, and whether these patients have factors associated with adverse pathology. METHODS: Patients with SRMs (≤4cm) who underwent surgical resection at our institution (2009-2015) were classified as undergoing early resection or initial surveillance with delayed resection (defined by a time from presentation to intervention of at least 6mo). Demographic and clinical variables were compared among groups. Using multivariable logistic regression, we examined the association between delayed resection and adverse pathology (Fuhrman grade 3-4, papillary type 2, sarcomatoid histology, angiomyolipoma with epithelioid features, or stage≥pT3). For patients who underwent delayed intervention, we used similar methods to examine the association between SRM growth rate and adverse pathology. RESULTS: Overall, 401 (81%) and 94 (19%) patients underwent early and delayed resection, respectively. Median time to resection was 84 days (interquartile range: 59-121) and 386 days (interquartile range: 272-702) (P<0.001). Patients undergoing delayed resection were older (62 vs. 58y, P = 0.01) and had smaller masses (2.3 vs. 2.7cm, P<0.001) at initial presentation. Utilization of partial vs. radical nephrectomy was similar regardless of resection timing (P = 0.5). Delayed resection was not associated with adverse pathology (P = 0.8); however, male sex was independently associated with adverse pathology (odds ratio: 1.7, 95% CI: 1.1-2.4, P = 0.009). In patients on surveillance, increasing annual SRM growth rate was associated with adverse pathology (odds ratio: 1.2, 95% CI: 1.03-1.3mm/y, P = 0.02). CONCLUSIONS: Delayed resection was not associated with adverse pathology. Patients on surveillance with increased SRM growth rates had a modest but significant increase in the risk of adverse pathology.