Assessment of Perioperative Variables That Predict the Need for Surgical Drains Following Robotic Partial Nephrectomy Utilizing Quantitative Drain Creatinine Analysis

Abstract

OBJECTIVE: To utilize body fluid creatinine analysis to determine which patients will require a surgical drain following robotic-assisted partial nephrectomy (RAPN). MATERIALS AND METHODS: One hundred fifty consecutive RAPN performed by a single surgeon were reviewed. Postoperative day (POD) 1 drain creatinine was compared to serum creatinine to calculate the drain to serum creatinine ratio (D/S ratio). Elevated D/S ratio was defined as any value >1.2. RESULTS: From February 2008 to April 2015, 140 patients underwent RAPN and had a drain placed (124 had D/S ratio available on POD 1). In the 103 patients with a D/S ratio of <1.2 and the 21 with D/S ratio of >1.2, the mean tumor size was 3.0 and 3.9 cm (P = .001) and mean RENAL score was 7.6 and 8.1 (P = .270), respectively. Collecting system entry occurred in 68.2% of patients with a D/S ratio of <1.2 and 71.4% of patients with a D/S ratio of >1.2. Mean drain time was 2.4 and 4.2 days (P = .001), hospital stay was 2.7 and 3.3 days (P = .036) for the D/S ratio <1.2 and D/S ratio >1.2 groups, respectively. Those with renal mass size of 4-7 cm had increased likelihood of D/S ratio >1.2 (OR 2.78; P = .041). CONCLUSIONS: Most RAPN do not require a surgical drain. A POD 1 elevated D/S ratio is more likely to occur with larger masses (those approaching or greater than 4 cm) and can be associated with prolonged drain time and hospital stay.