Microdiscectomy is a term used to describe a partial discectomy where the surgeon uses magnifying optics during the procedure. Microdiscectomies are always performed posteriorly (from the back). Often a flavectomy and laminotomy are performed during this procedure to allow the surgeon access to affected area.
Fusions and artificial disc replacement require a total discectomy to make room for the inserted bone in the fusion and the prosthetic in the artificial disc replacement. Total discectomies are done anteriorly (from the front).