Comparative evaluation of microdiscectomy only, autograft fusion, polymethylmethacrylate interposition and threaded titanium cage fusion for treatment of single-level cervical disc disease: a prospective randomized study in 125 patients. - Bärlocher,C.B.; Barth,A.; Krauss,J.K.; Binggeli,R.; Seiler,R.W. (Neurosurg Focus, 2002)