[Usefulness of the indocyanine green fluorescence imaging technique in laparoscopic partial nephrectomy]

To detail a novel technique for marking renal tumors with intravenous indocyanine green (ICG) during laparoscopic partial nephrectomy, and to investigate the feasibility and safety of this technique with the use of near-infrared fluorescence imaging.

Between July 2019 and January 2020, 25 consecutive cases with renal masses underwent intraoperative ICG tumor marking laparoscopic partial nephrectomy, at the department of urology in Peking University Third Hospital by the same surgeon. The key benefits included quick intraoperative identification of the mass with improved visualization and real-time control of resection margins by the ICG Immunofluorescence imaging technique. Clinical data were prospectively collected in our institutional database. Perioperative, pathological, and clinical outcomes of the partial nephrectomy were assessed. Measurement data with normal distribution and count data were respectively described as M(range) and percentage. Among these cases, 16 cases were male and 9 cases female, The median body mass index was 25.4 (20.0-35.4) kg/m². The average age was 54 (29-77) years. The maximum tumor diameter was 2.75(1.30-5.20) cm. The R.E.N.A.L score was 7.5 (5.0-10.0).The tumor locations were distributed with upper pole (11, 42%), middle (6, 23%), and lower pole (9, 35%).The clinical stages of the tumor were described as follows: T1aN0M0 (23, 88.5%), T1bN0M0(2, 7.7%), T2aN0M0 (1, 3.8%).

All the 25 cases were performed 26 times with intraoperative ICG tumor marking laparoscopic partial nephrectomy. There were no allergy, infection and other complications with intravenous indocyanine green. The surgical procedure was successful in all the patients. No conversion and blood transfusion were needed. All the cases of the surgical margin were negative. Overall the operative time was 136 (50-247) min and warm ischemia time was 14 (7-30) min.The estimated blood loss was 50 (10-400) mL and the hospital stay was 5.5 (3.0-31.0) days. One case with perirenal hematoma, one case with urine leak, one with respiratory failure and deep venous thrombosis. All of these cases were cured by the corresponding treatment. The others had no severe complications. There was no tumor recurrence and metastasis during the follow up with 4 to 10 months.

ICG marking and near-infrared fluorescence imaging technology has now emerged as a safe, feasible and useful tool that may facilitate laparoscopic partial nephrectomy.