2018 AMI Online Salon

Freehand Subaxial Pedicle Screw Placement

Project Details

  • Artist(s):  Kristen Larson Keil; Phoenix, Arizona
  • Client: Jay Turner, MD
  • Copyright: © 2018 Barrow Neurological Institute
  • Medium / software used: Adobe Photoshop
  • Final presentation format: Printed neurosurgical journal article
  • Primary audience: Attending and resident neurosurgeons

Project Description

Accuracy of pedicle screw placement in the subaxial cervical spine is imperative given the small size of the pedicles combined with the close proximity of the adjacent neural structures and vertebral artery. This series of illustrations outlines the key points of the Freehand technique.

Choosing the correct entry point and screw trajectory is of utmost importance for preventing breach with these screws. With the freehand technique, preoperative CT is used to study bony anatomy and a hemilaminotomy is performed (Figure A). This enables direct palpation and visualization of the pedicle (highlighted in orange) and its junction with the posterior wall of the vertebral body (highlighted in blue). A Penfield 4 dissector is placed along the medial border of the pedicle to retract the dura and aid with visualization. The resulting cranial/caudal trajectory through the very middle of the pedicle is determined by this direct palpation and visualization of the medial pedicle wall. (Figures B-D)