Pedicle screw malposition is a common problem for spine surgeons. A poorly placed screw can lead to potentially serious complications (hemorrhage, paralysis) in the short- or medium-term. Accurate images during surgery facilitates preoperative planning and aids the placement of pedicle screws.

Surgical navigation covers all techniques and equipment (hardware and software) needed to perform a computer-assisted procedure with 3D image visualization of the surgical act.

Surgical navigation systems have been on the market for about 15 years. Surgical navigation increases the accuracy of pedicle screw placement. Many technologies are available, but they are expensive and often require extensive instrumentation.

The PYTHEAS® ODYSSEE angular assistance system has many advantages over more widely used systems. Indeed, this system provides surgeons with the necessary information to correctly insert pedicle screws during posterior spondylodesis procedures for the treatment of deformity, osteoarthritis (degenerative spine) and trauma.

Compared to competing solutions, the purpose of this device is to reduce pedicle screw malpositioning while offering minimal radiation exposure and the least possible impact on the conventional surgical workflow. It is a lightweight, efficient and easy-to-use medical device with 2-step functionality: 1) Surgical planning of pedicle screws based on a preoperative scan; 2) Angular assistance tool during surgery.

The study investigators wish to evaluate the performance and safety of the PYTHEAS® ODYSSEE medical device (not CE marked) as well as its usability in a pilot study of first use in humans.

Without a navigation system, the literature reports that on average 9 to 10% of perforations are incorrectly positioned by the "free hand" method. With the PYTHEAS® ODYSSEE angular assistance device, the study hypothesis is that this rate will be 5%, i.e. a 50% improvement.

Inclusion Criteria:

• Patient with indication for posterior arthrodesis of at least 2 lumbar or thoracic vertebrae with placement of pedicle screws at vertebral level for :

  • Traumatology: fracture with significant vertebral compression or major kyphosis deformity, ligament and/or disc injury resulting in instability, with the need to free the marrow or nerve roots, OR
  • Deformity: idiopathic scoliosis with surgical indication for increased curvature, thoracic curvature greater than 45° or lumbar curvature greater than 35°, OR
  • Revision surgery for extension of the assembly in the presence of a possible adjacent syndrome responsible for instability and/or central or foraminal stenosis, OR
  • Degenerative: symptomatic spondylolisthesis, degenerative scoliotic deformity, narrow lumbar canal with canal release leading to instability, syndrome adjacent to a previously performed montage.

• The patient must have given their free and informed consent and signed the consent form

• The patient must be a member or beneficiary of a health insurance plan

Exclusion Criteria:

• Patients with contraindication to screw placement
• Patients with contraindication to CT scan
• Silicon allergy
• The subject is participating in a category 1 interventional study, or is in a period of exclusion determined by a previous study
• The patient is unable to express their consent
• It is impossible to give the subject informed information
• The patient is under safeguard of justice or state guardianship
• Pregnant, parturient or breastfeeding