title: Perforation rates of cervical pedicle screw insertion by disease and vertebral level.
abstract: BACKGROUND
  Different perforation rates for cervical pedicle screws by disease are expected in relation to bone quality and pedicle morphology; however, no report comparing pedicle screw perforation rate by disease had previously been published. This study investigated the perforation rates of pedicle screws inserted to cervical pedicle by disease and vertebral level using a CT-based navigation system.
  
  
  METHODS
  Fifty-three patients who underwent cervical pedicle screw insertion using CT based navigation system were studied. Diseases included rheumatoid arthritis (RA) (24 cases), destructive spondyloarthropathy (DSA) (10), cervical spondylotic myelopathy (CSM) (9), spine tumor (6), and cervical spondylotic myelopathy associated with athetoid cerebral palsy (CP) (4). Screw perforation rates for cervical pedicle screws were studied. Major perforation was defined as perforation 50% of screw diameter or more.
  
  
  RESULTS
  Major perforation rate by disease from C3 to C7 was as follows: spine tumor (0/24, 0%), RA (2/59, 3.4%), DSA (3/65, 4.6%), CP (2/20, 10.0%), and CSM (6/40, 15.0%). There were no clinically important complications such as vertebra arterial injury, spinal cord injury, or nerve root injury caused by any screw perforation. Major perforation rate by vertebral level was: C2(2/30, 6.7%), C3(4/49, 8.2%), C4(6/43, 14.0%), C5(1/32, 3.1%), C6(1/41, 2.4%), and C7(1/45, 2.2%), showing highest rate for C4, followed by C3.
  
  
  CONCLUSIONS
  Cervical pedicle screw perforation rate by disease was higher in CSM compared to RA and DSA. The perforation rate by vertebral level was higher for C4 and C3, in this order.
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University, School of Medicine, 3-1-1 Asahi, Matsumoto-City, Nagano, 390-8621, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Uehara
authors.forename: Jun
authors.initials: J
authors.lastname: Takahashi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hirabayashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hashidate
authors.forename: Nobuhide
authors.initials: N
authors.lastname: Ogihara
authors.forename: Keijiro
authors.initials: K
authors.lastname: Mukaiyama
authors.forename: Shota
authors.initials: S
authors.lastname: Ikegami
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kato
references.citation: Eur Spine J. 2007 Apr;16(4):485-94
references.pmid: 17024400
references.citation: Rheumatol Int. 2007 Apr;27(6):567-74
references.pmid: 17094002
references.citation: Clin Orthop Relat Res. 1999 Feb;(359):77-88
references.pmid: 10078131
references.citation: J Neurosurg. 1999 Jan;90(1 Suppl):19-26
references.pmid: 10413121
references.citation: J Spinal Disord. 2000 Feb;13(1):63-72
references.pmid: 10710153
references.citation: Neurol Med Chir (Tokyo). 2007 Mar;47(3):102-7; discussion 107-8
references.pmid: 17384491
references.citation: J Neurosurg. 2003 Oct;99(3 Suppl):257-63
references.pmid: 14563142
references.citation: Spine (Phila Pa 1976). 1997 May 1;22(9):977-82
references.pmid: 9152447
references.citation: J Spinal Disord Tech. 2005 Feb;18(1):23-8
references.pmid: 15687848
references.citation: Spine (Phila Pa 1976). 1994 Nov 15;19(22):2529-39
references.pmid: 7855677
references.citation: Spine J. 2009 Sep;9(9):729-34
references.pmid: 19699462
references.citation: Eur Spine J. 2009 Sep;18(9):1293-9
references.pmid: 19488794
references.citation: Spine (Phila Pa 1976). 1997 Aug 15;22(16):1853-63
references.pmid: 9280021
references.citation: Rheumatol Int. 2007 Apr;27(6):579-84
references.pmid: 17287933
references.citation: J Spinal Disord. 1994 Feb;7(1):19-28
references.pmid: 8186585
references.citation: Spine (Phila Pa 1976). 2000 May 15;25(10):1197-205
references.pmid: 10806495
references.citation: Spine (Phila Pa 1976). 1997 Jan 1;22(1):1-6
references.pmid: 9122772
references.citation: J Spinal Disord. 1994 Jun;7(3):222-9
references.pmid: 7919645
references.citation: J Spinal Disord Tech. 2005 Jun;18(3):283-5
references.pmid: 15905775
references.citation: Int Orthop. 2009 Aug;33(4):895-903
references.pmid: 19421752