“…A difference in CPS perforation rate according to bone quality or morphology of pedicle is to be expected; however, whether there are differences in CPS perforation rate due to variation in bone quality because of osteoporosis or osteosclerotic pedicle, or by morphology or size of pedicles, is not clearly understood. In addition, differences in CPS perforation rates according to disease may exist; however, although CPS perforation rates for rheumatoid arthritis (RA), DSA, and trauma treatment by various procedures have been *Address correspondence to this author at the Department of Orthopaedic Surgery, Shinshu University, School of Medicine, 3-1-1 Asahi, MatsumotoCity, Nagano, 390-8621, Japan; Tel: 81-263-37-2659; Fax: 81-263-35-8844; E-mail: jtaka@shinshu-u.ac.jp reported [8][9][10][11][12], there have been no reports on CPS perforation rates by disease. The purpose of this study is to evaluate the perforation rates of cervical pedicle screw insertion using CT-based navigation system by disease and vertebral level (from C2 to C7).…”