title: Lumbosacral fixation using sacroiliac buttress screws: a modification to the Jackson technique with intrasacral rods.
abstract: BACKGROUND
  The use of intrasacral rods has been previously reported for posterior lumbosacral fixation. However, problems associated with this technique include poor stability of the rod in the sacrum, difficulty in contouring the rod to fit the lateral sacral mass, and the complicated assembly procedure for the rod and pedicle screws in the thoracolumbar segments after insertion of the rod into the sacrum.
  
  
  METHODS
  We used a screw with a polyaxial head instead of an intrasacral rod, which was inserted into the lateral sacral mass and assembled to the rod connected cephalad to pedicle screws. The dorsal side of the screw was stabilized by the sacral subchondral bone at the sacroiliac joint with iliac buttress coverage, and the tip of the screw was anchored by the sacral cortex.
  
  
  RESULTS
  Three different cases were used to illustrate lumbosacral fixation using intrasacral screws as an anchor for the spinal instrumentation. Effective resistance of flexural bending moment and fusion were achieved in these patients at the lumbosacral level.
  
  
  CONCLUSIONS
  An intrasacral screw can be stabilized by subchondral bone with iliac buttress coverage at the dorsal and ventral sacral cortex. Posterior spinal fusion with this screw technique enables easier assembly of the instrumentation and presents better stabilization than that provided by the previously reported intrasacral rod technique for correction and fusion of thoracolumbar kyphoscoliosis.
authors: Department of Orthopedic Surgery, National Hospital Organization, Murayama Medical Center, 2-37-1, Gakuen, Musashimurayama, Tokyo 208-0011, Japan ; Department of Orthopedic Surgery, Saiseikai Yokohamashi Tobu Hospital, 3-6-1, Shimosueyoshi, Tsurumi-ku, Yokohama 230-8765, Japan.
authors: Kentaro
authors: K
authors: Fukuda
authors: Department of Orthopedic Surgery, National Hospital Organization, Murayama Medical Center, 2-37-1, Gakuen, Musashimurayama, Tokyo 208-0011, Japan.
authors: Masakazu
authors: M
authors: Takemitsu
authors: Department of Orthopedic Surgery, National Hospital Organization, Murayama Medical Center, 2-37-1, Gakuen, Musashimurayama, Tokyo 208-0011, Japan.
authors: Masafumi
authors: M
authors: Machida
authors: Department of Orthopedic Surgery, National Hospital Organization, Murayama Medical Center, 2-37-1, Gakuen, Musashimurayama, Tokyo 208-0011, Japan.
authors: Takashi
authors: T
authors: Asazuma
keywords: Iliac buttress; Intrasacral screw; Lateral sacral mass; Posterior lumbosacral fixation; Surgical technique