The microendoscopic discectomy(MED) techniqur was initially developed in 1997 and was a relatively new procedure providing minimally invasive access to the spinal column.This systerm offers many advantages over other minimally invasive surgical lumber discectomy techniqurs.Sofamor Danek developed the instruments and technology,enabling surgeons to successfully address free-fragment disc pathological factors and lateral recess stenosis,even for contralateral spinal decompression from an ipsilateral approach.The first clinical series using this technique for 151 caess was in 1999 in our hospital,and then 1058 patients have benn treated by this procedure in following 5 years,a 5 years following-up study of 151 cases in 1999 helped us determining the efficacy of this systerm in treating lumber disc diseases,the procedure were performed by orthopaedic doctors who are specialisted in spine.