 Patients randomized to negative pressure group will received negative pressure dressing Pico Wound Management System - manufacture by Smith Nephew associated with Acticoat Flex dressing which will be applied immediately after skin closure in a conventional way and left in place for 7 days. Negative pressure dressing will be changed once during 7 days period - after day 2 to 4. Wound complications within first 30 days of surgery will be recorded on clinical examination. 