Lumbar Facet Syndrome

Anatomy

The lumbar spine is composed of a number of vertebrae with a rounded, solid front portion and an irregularly shaped, open bony archway in the rear portion that join to form the spinal canal.  The archways at each level meet to form cartilage-lined joints, called facet joints.  These joints are surrounded by a lubricating capsule.  Facet joints help to stabilize the spine, while still allowing the spine to bend and twist.

The Problem

Facet joints can deteriorate over time.  They may become damaged by injury to the back, general wear and tear, or due to changes in mechanical loading occurring when discs deteriorate. (See Degenerative Disc Disorder)

Facet joints are subject to the aging process, just like other cartilage-lined joints in the body.  Cartilage begins to wear away over time, leading to stiffness and inflammation.  When accompanied by degenerative changes in the discs, abnormal motion and bone on bone contact can occur in the facet joints.  This can produce stiffness or limited motion.  Bone spurs begin to form at the edges of the affected joints.

These changes can give rise to pain.  Pain may be limited to the low back or may spread to the buttocks or the back of the thighs.

Diagnosis

Lumbar facet syndrome cannot be diagnosed on the basis of spinal images, although an MRI can give an indication of the severity of degenerative changes involving the facet joints.  Similarly, there are no physical examination findings that confirm the diagnosis.  Pain with stress on the joints, usually when bending backwards (extension) suggests the diagnosis.  Pain from lumbar facet joints involves the low back, buttocks or the back of the thigh.

Injection of a small amount of local anesthetic can be performed as a way to diagnose facet joint syndrome.  Typically, the small nerve branch that supplies the facet joints at the level where pain is suspected is injected, using the fluoroscope for guidance.  The anesthetic temporarily numbs the facet joint.  Good short-term pain relief from these so-called medial branch blocks helps to confirm that pain is coming from the facet joints that have been blocked.  Some providers will inject the facet joint itself with local anesthetic or steroid medication to help confirm the diagnosis.

Treatment

Treatment may include temporary rest or avoidance of painful positions and heat, ice or the use of anti-inflammatory medications.  Physical therapy is useful to establish a program of bending (flexion) exercises that help to lubricate the cartilage and restore more normal motion to the facet joints.

If anesthetic blocks confirm that pain is coming from the facet joints, a local radiofrequency heating procedure of the medial branch can be performed using a needle under fluoroscopic guidance.  This procedure, known as radiofrequency ablation, can provide pain relief that lasts 6-12 months at a time.