Impact of Patient Factors on Robotic-Assisted Partial Nephrectomy Operating Room Times: The Case for Fixed Operating Room Time as a Viable Efficiency Target

Introduction: To analyze the association of patient characteristics on operating room (OR) times for robotic-assisted partial nephrectomies (RAPNs). Methods: In total, 248 consecutive RAPNs were performed by a single surgeon from October 2018 to August 2022. Data were collected on the following patient factors: sex, age, race, weight, body mass index (BMI), diabetes, hypertension (HTN), tumor side, tumor mass, and American Society of Anesthesiologists (ASA) score. Total fixed OR times were evaluated as the sum of in-room time to anesthesia-release time (IRAT), anesthesia-release time to cut time (ARCT), close time to wheels out time (CTWO), and in-room time to cut time (IRAT + ARCT). Total variable OR times were defined as cut time to close time (CTCT). Total operative time was defined as wheels into wheel out (WIWO). Results: Median OR time was 265 minutes (interquartile range [IQR]: 247-298 minutes) for WIWO, 191 minutes (IQR: 170-225 minutes) for CTCT, and 75 minutes (IQR: 68-83 minutes) for total fixed time. There was a significant increase in WIWO with the following patient variables: male sex (18.0 minutes, 95% confidence interval [CI]: 6.3-29.7 minutes), weight (5.6 minutes, 95% CI: 2.8-8.4 minutes), BMI (14.3 minutes, 95% CI: 4.2-24.4 minutes), HTN (15.1 minutes, 95% CI: 3.7-26.5 minutes), pathology tumor size (cm) (6.4 minutes, 95% CI: 2.2-10.6 minutes), and ASA score (13.8 minutes, 95% CI: 3.1-24.4 minutes). Sex, age, BMI, weight, HTN, and pathology tumor size significantly impacted CTCT (P < 0.05). Total fixed OR time was only affected by ASA score (P = 0.02). Conclusions: Patient variables significantly affect total OR time and variable OR time. These variables do not impact total fixed OR times, confirming fixed OR time as a viable OR efficiency point.