Ultrasound(US)-guided Fusion Imaging-Assisted Facet Joint Injections: A Didactical Approach
Turtulici G 1 , Caruso P 1 , Fabbro E 2 , Orlandi D 2 , Ferrero G 2 , Silvestri E 1
1 Diagnostic Imaging and Interventional Ultrasound Ospedale Evangelico Internazionale, Genoa, Italy
2 University of Genoa Department of Radiology, Genoa, Italy
BACKGROUND
Facet joints (FJs) or zygoapophysial joints (Z-joints) are one of the most ignored joints in the body, but they play a key role in allowing for smooth spine motion.
Located posterior to the vertebral body, FJs are synovial diarthrosis on the side of the vertebral column nearest from the surface of the skin.
FJs allow the spine considerable variety of movement and flexibility, but they also prevent excessive or extreme movement, such as hyperextension, hyperflexion, and work against such injuries as whiplash.
Each spine vertebra communicates with each other with four small arm-like extensions or articulating processes: two pointing up (superior process) and two down (inferior process); the inferior process of the vertebra communicates with the superior process of the vertebra below and the superior process communicates with the vertebra above.
Together with a disc that sits between the bodies of the two vertebra they form a three joint complex, that consist of vertebral body-disc-vertebral body joint and two facet joints.
The inner surface of the facet joint serves as an outer wall of an opening or a foramen for a spinal nerve, through which it exits.
The disc and the junction of the two vertebral bodies serve as an inner wall of this foramen.
FJ patologic changes can be responsible of 15-40% of Low Back Pain.
A correct diagnosis can be made with TC or MRI demonstrating inflammation, irritation, swelling, or degenerative changes of facet joints.
In such cases, FJ intra-articular injections with local anesthetics or anti-inflammatory drugs can be made with diagnostic or therapeutic purpose.
