title: Anterior transarticular screw fixation as a conventional operation for rigid stabilization.
abstract: BACKGROUND
  Anterior transarticular screw (ATS) fixation is a useful surgical option for atlantoaxial (AA) stabilization. This report presents a revised ATS method for AA fusion.
  
  
  METHODS
  A 79-year-old male presented with AA instability attributed both to an old odontoid fracture and severe degeneration of the lateral atlantoaxial joints (LAAJs). ATS fixation was performed through the conventional anterior cervical approach. The longest screw trajectories were planned preoperatively using multiplanar reconstruction computed tomography (CT) scans, with entry points of the screws situated at the midpoint on the inferior border of the axial body. The surgical exposure was limited to opening at the entry points alone. Our retractor of choice was the Cusco speculum; it sufficiently secured space for utilizing the required instruments for screw placement while offering sufficient protection of soft tissues. Cannulated full-threaded bicortical screws stabilized the LAAJs. Screw insertion required a significant amount of coronal angulation up to the superior articular process of the atlas under open-mouth and lateral fluoroscopy image guidance. After ATS fixation, bone grafting was performed between the posterior laminae of the axis and the atlas through a conventional posterior approach.
  
  
  RESULTS
  Bony fusion between the atlas and the axis was confirmed radiographically. Arthrodesis of the LAAJs occurred despite no bone grafting.
  
  
  CONCLUSIONS
  Rigid fixation of the LAAJs was obtained by our ATS technique, indicating that it is an alternative method for AA fixation when posterior rigid internal fixation is not applicable.
authors.affiliation: Department of Neurosurgery and Spine Surgery, Iseikai Hospital, Osaka, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: Department of Neurosurgery and Spine Surgery, Iseikai Hospital, Osaka, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Matsumoto
authors.affiliation: Department of Neurosurgery and Spine Surgery, Iseikai Hospital, Osaka, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tsuruzono
authors.affiliation: Department of Neurosurgery and Spine Surgery, Iseikai Hospital, Osaka, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yoshimura
authors.affiliation: Department of Neurosurgery and Spine Surgery, Iseikai Hospital, Osaka, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Shibano
authors.affiliation: Graduate School of Health Care Sciences, Jikei Institute, Osaka, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yonenobu
keywords: Anterior transarticular screw fixation; atlantoaxial instability; facet degeneration; odontoid fracture