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. Surgical navigation has a great potential to improve the accuracy of correctly implanting these devices; however, present technologies rely on intraoperative imaging that uses ionizing radiation (e.g. computed tomography, fluoroscopy, etc.), require cumbersome set-ups, the physical attachment of fiducial markers, and cannot account for patient motion. Therefore, the investigators propose a real-time intraoperative optical topographical imaging based surgical guidance system capable of accurately guiding the placement of implanted devices such as pedicle screws.

The hypothesis is that optical visualization of surgically exposed bony anatomy with computerized navigation can accurately estimate subsurface anatomy and in the future, potentially guide the placement of pedicle screws during spinal surgery. The specific research aims are as follows: i) an intraoperative non-contact optical imaging system can quantify the entry point and trajectory of pedicle screws implanted by the spine surgeon; and ii) intraoperative optical imaging can predict the entry point and trajectory of pedicle screws as verified by post-operative computed tomography (CT) scans.

Inclusion Criteria:

• Greater than 18 years of age
• Able to provide consent, or have substitute decision maker available FOR SPINAL INDICATIONS
• Scheduled to undergo spinal instrumentation surgery involving pedicle screw insertion
• Scheduled for pre-operative CT scan and the surgical plan includes open exposure of the posterior bony elements of one or more level(s) of the vertebra(e)
• No contra-indication for a post-operative CT scan FOR CRANIAL INDICATIONS
• scheduled to undergo cranial surgery
• Scheduled for pre-operative CT or MRI scan
• No contra-indication for post-operative CT scan

Exclusion Criteria:

• Previous spinal decompression with significant laminectomy performed at the level intended for instrumentation
• Previous spinal decompression with laminoplasty performed at the level intended for instrumentation