title: Identification of the anterior and posterior portions of the lateral pedicle cortex by roentgenograms in pedicle screw fixation.
abstract: Forty lumbar pedicles and pedicle screws in four cadavers were used to identify the anterior and posterior portions of the lumbar pedicle cortex by roentgenograms in order to evaluate the penetration of the pedicle cortex by pedicle screws intraoperatively. Firstly, the transverse pedicle angles were measured on roentgenograms. Three roentgenograms were taken on each pedicle in three different directions: (1). medial to the pedicle axis; (2). pedicle axis; (3). lateral to the pedicle axis. They revealed that the anterior portion of the lateral pedicle cortex was demonstrated by the pedicle lateral outline on the roentgenogram medial to the pedicle axis, and the posterior portion by the pedicle lateral outline on the roentgenogram lateral to the pedicle axis. Wire markers were used to confirm these data. Finally, anterior and/or posterior penetrations on the lateral pedicle cortex in pedicle screw fixation were studied by roentgenograms in these cadavers and showed that anterior penetration of lateral cortex was demonstrated by the view medial to the pedicle axis, and posterior penetration by the view lateral to the pedicle axis. It is concluded that projections medical and lateral to the pedicle axis are necessary to identify lateral screw penetration intraoperatively when X-ray checking is used.
authors.affiliation: Department of Physical Medicine ansd Rehabilitation, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA. yaominggu@yahoo.com
authors.forename: Y
authors.initials: Y
authors.lastname: Gu
authors.forename: N A
authors.initials: NA
authors.lastname: Ebraheim
authors.forename: R A
authors.initials: RA
authors.lastname: Yeasting
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D011859:Radiography; D013123:Spinal Fusion