For a significant number of patients suffering from back pain, even basic daily activities become impossible. It is at this time that spinal surgery becomes necessary in order to improve the patient's quality of life. To combat these symptoms, surgical implants (e.g. pedicle screws, rods, etc.) are used to aid in stabilizing and correcting the deformities of the spine, particularly after spinal decompression. The clinical need for spinal surgery is compounded by current and continuing demographic trends. As the general population continues to age, the number of orthopaedic surgical interventions is expected to rise drastically. Therefore, a significant opportunity exists for the implementation of surgical guidance technologies, for orthopaedic procedures, to combat this overwhelming health care burden.

The hypothesis is that optical visualization of surgically exposed anatomy with the Biophotonics and Bioengineering Lab (BBL) surgical navigation prototype, when registered with pre-operative imaging (CT or MRI), can accurately estimate subsurface anatomy and allow tracking the position of surgical instruments in real-time, using an intraoperative non-contact optical imaging system during spinal surgical procedures.

Inclusion Criteria:

• Greater than 18 years of age, able to provide consent, or has substitute decision maker available to consent.
• Scheduled to undergo spinal instrumentation surgery involving pedicle or lateral mass screw insertion.
• Scheduled for pre-operative CT scan and the surgical plan includes open exposure of the posterior bony elements of two or more level(s) of the vertebra(e).
• No contra-indication for a post-operative CT scan.

Exclusion Criteria:

• Previous spinal decompression with significant laminectomy performed at the level intended for instrumentation.
• Previous spinal instrumentation with significant metallic artefact on pre-operative CT scan