Excision of necrotic tissue; generally, debridement
This term got 120 hits on 23.11.2016 and is popular in primary surgical literature of recent vintage. Necrosectomy may offer no advantage over debridement, which got 2,450,000 hits. Both terms are used in the working medical parlance.
Reference JAMA. 2012 Mar 14;307(10):1053-61