Fluoroscopy-Assisted C1–C2 Posterior Fixation
for Atlantoaxial Instability
Odontoid fractures, arthritis, and cervical tumors are among the possible factors that may lead to Atlantoaxial Instability. Failure to treat the destabilized atlantoaxial segment can result in abnormal translational and rotational movements that may cause neck pain and increase the likelihood of spinal cord compression.
Both the atlantoaxial transarticular screw (TAS) technique and the screw and rod construct (SRC) technique can achieve atlantoaxial stability without requiring external immobilization. If the screws are placed too far to the side during the procedures, the atlantoaxial transarticular screw (TAS) technique and the screw and rod construct (SRC) technique could lead to vertebral artery injury (VAI) or spinal cord injury, respectively.
Although navigated surgery has demonstrated significant benefits, its adoption for spine surgery has been slower compared to cranial applications. This is partly because the setup of spinal navigation devices is relatively complex and time-consuming.
Treating cervical instability and pain through non-navigated posterior C1-C2 fixation, employing both TAS and SRC, has been proven to be an effective treatment. The median operating room (OR) time for SRC may be slightly longer than that of TA, but this can vary. The surgical time can be influenced more by user experience and surgical technique rather than the implementation of navigation technology itself.
The amount of blood loss is typically less for the atlantoaxial transarticular screw (TAS) technique compared to the screw and rod construct (SRC), which is to be expected as TAS is a minimally invasive approach.
The variation can be further clarified by the harm caused to the venous plexuses during the dissection required for the placement of the C1 screw. Incorporating navigation technology can potentially lower blood loss for both surgical methods. One possible explanation for this is that a less invasive approach is utilized, which leads to reduced handling near the cervical venous plexuses.
Vertebral artery injury is a widely recognized and hazardous complication linked with screw malpositioning in both TAS and SRC procedures, although the probability of this happening is very low.
Changes in the screw’s initial position can have an effect on the precision of C1 screw placement. Sacrificing the C2 nerve root leads to fewer screws being misplaced. By using a study aided by fluoroscopy, a high level of precision can be attained, which can be assessed by postoperative CT scans.
One of the key reasons to consider using surgical navigation in cervical spine surgery is to prevent potential complications like vertebral artery injury (VAI) during instrumentation.
While surgical navigation cannot entirely eradicate this risk, it has demonstrated advancements in screw precision as compared to non-navigated free-hand procedures.
Other techniques that can be employed to prevent vertebral artery injury (VAI) include the utilization of probing technologies that are based on doppler, impedance, or optical properties. In the intervention group, doppler probing can be conducted during lateral dissection, as well as stepwise drilling and tapping, to prevent vertebral artery injury (VAI). This technique is a valuable resource for both fluoroscopy-assisted and navigated C1-C2 surgical procedures.
The Pediguard, an electronic conductivity device (manufactured by SpineGuard, Paris, France) that aids in the placement of pedicle screws, has been utilized in fluoroscopy-assisted cadaveric procedures to prevent vertebral artery injury (VAI). An optical technique called Diffuse Reflectance Spectroscopy has been incorporated into a surgical device to identify potential cortical breach during the insertion of pedicle screws.
The advancement and integration of innovative supportive technologies offer a potential to enhance the safety of all types of spinal surgeries involving instrumentation. Until the implementation of supportive technologies, experienced surgeons may consider non-navigated C1-C2 fixation as a viable choice for stabilizing the atlantoaxial segment.
Posterior stabilization of C1-C2 with both transarticular screw (TAS) and screw and rod construct (SRC) is a secure and efficient approach for treating atlantoaxial instability, which typically results in pain relief in most cases.
C1-C2 Facet Joint Illustrated