Evaluation of renal defect healing, hemostasis, and urinary fistula after laparoscopic partial nephrectomy with oxidized cellulose

BACKGROUND AND PURPOSE: Laparoscopic partial nephrectomy (LPN) has been performed at several institutions using oxidized cellulose (OC) as a means of bleeding and urinary fistula (UF) prevention. However, a foreign-body reaction mimicking either abscess or tumor recurrence has been associated with the use of OC. We evaluated renal-defect healing after LPN with and without OC. MATERIALS AND METHODS: Sixteen female Landrace pigs underwent lower-pole excision; all the collecting systems were entered and then closed with absorbable running suture. In group 1, hemostatic U-shaped stitches were the only method of hemostasis. In group 2, a bolster of OC was added to the renal defect. The pigs were sacrificed at 1, 4, 7, or 21 days, and gross findings such as perirenal collection were observed. A catheter was advanced up to the kidney, and methylene blue was injected with collecting system pressure observation; burst pressure was defined as the appearance of extravasation. High risk for UF was defined as burst pressure <10 mm Hg. RESULTS: Neither hemorrhage nor urinoma was observed during sacrifice. One pig from group 2 had a burst pressure of 4 mm Hg At 7 days (high risk for UF). At 21 days in group 2, the tissue was grossly solid, apparently a granuloma. Suppuration tended to be greater in group 2. The foreign-body reaction was more intense in group 2 and was strongly present at 4, 7, and 21 days. CONCLUSIONS: The use of OC is associated with higher scores of suppuration and foreign-body reaction. After LPN with OC, postoperative day 7 might be a critical time for the development of urinary leakage.