What is Facet Arthropathy?
The spine is made up of bones, discs and facet joints. The discs and facet joints allow the spine to flex, extend, turn and bend to the sides. The discs are located in the front of the spine; they support and allow movement between the vertebral bodies. The facet joints are located in the rear of the spine, one to two inches off the midline on the right and left sides. Facet joints are synovial joints lined with cartilage and filled with fluid. Each joint is held together by a thick capsule. These small joints allow the facet bones to slide back and forth with minimal resistance.
Unfortunately over time the facet joints break down from aging, wear and tear, injury, instability, and slippage of the spine. The gradual wear of the facet joints is called degeneration. These degenerative changes of the facet joints can produce severe debilitating pain.
Facet arthropathy is often called as arthritis of the facet joint. The most common cause of facet arthritis is osteoarthritis. Osteoarthritis causes breakdown and swelling in the cartilage of the facet joint, ultimately producing bone on bone rubbing or grinding. The body tries to stop this rubbing by thickening the joint, creating arthritis. This type of arthritis may produce pain and stiffness which worsens with the extension of the neck or back. If the joints enlarge too much, they can pinch nerves causing arm or leg pain or numbness.
Facet arthritis in the neck causes neck and shoulder pain, in the midback it causes midback pain and in the lower back it causes lower back, buttock, upper leg, and occasionally lower leg pain. Pain usually increases with extending (bending back) or twisting the neck or back, and the affected joints may be very tender to deep pressure on examination.
How is Facet Arthropathy Diagnosed?
Facet arthropathy may be diagnosed on X-rays, CT and MRI scans. CT scans may show thickened and irregular facet joints. MRI scans may show fluid in the joints (joint swelling), thickened ligaments and bones, as well as pinched nerves. These imaging studies only show the physical abnormality. They do not indicate if these changes are responsible for your pain.
To determine which structure is causing the pain, the patient may undergo pain mapping. Injections are used to locate where the pain is coming from. Numbing medicine is injected into the facet joint or onto the facet nerve (medial branch nerve). If the facet joint is the cause of the pain, the pain will stop or decrease. If the pain does not improve, then it is originating from other structures, such as the bones, discs, ligaments, spinal nerves, etc.
How is Facet Arthropathy Treated?
Patients who have not been helped by conservative treatment may benefit from surgical intervention. Traditionally these patients had been treated with either a large open fusion surgery of the discs and facet joints or facet joint injections and radiofrequency ablation. Radiofrequency ablation is an interventional pain procedure where electrodes are placed onto the facet joints to burn the nerves transmitting pain from the damaged facet joints. The burning electrodes are placed onto the spine under X-ray guidance. The nerves usually recover from the injury after six months or so and the pain returns. Fortunately radiofrequency ablation can be repeated.
Are There Minimally Invasive Treatments for Facet Arthropathy?
Facet joint pain can be treated with the spinal endoscope. Endoscopic rhizotomy treats pain that originates from the facet joints and medial branch nerves. A high definition endoscopic video camera the size of a pen is inserted through a tiny incision into the painful facet joints. The facet joints are cleaned of the painful tissue and the medial branch nerves are found and cut under direct visualization through the endoscope. This is like a “root canal” for the spine. Patients usually have almost immediate pain relief and quick recovery. Endoscopic rhizotomy may produce pain relief for years, unlike radiofrequency ablation which must be repeated every six months or so.
Severe facet pain that is not responsive to endoscopic rhizotomy may be treated by endoscopic fusion. Endoscopic rhizotomy blocks the majority of pain transmission from the joints, but not all. This prevents the patient from accidentally injuring himself. If the spine is unstable and puts extensive stress on the facet joints, or if there is significant pain originating from the disc or other structures, the spine may still need to be fused. Fortunately there has been much advancement in fusion technology and it can now be accomplished using minimally invasive surgery. This procedure is performed through a one inch incision with the help of endoscope or microscope.
Endoscopic fusion treats degenerative spinal disease and instability which can cause back and leg pain. The damaged disc is removed through the endoscope and spinal endplates are prepared for fusion under direct visualization. Endoscopic fusion is done under general anesthetic, facilitating the insertion of spinal instrumentation. Patients are usually discharged the same day after surgery, and have much less pain and a quicker recovery compared to traditional fusion surgery.