As stated in last week’s article, low back pain (LBP) can arise from many different structures. Lumbar facet syndrome is one that involves the facet joint and includes both acute (new) and chronic (old) varieties. The facet joint is synonymous with the zygapophyseal joint, so if you hear that word, don’t let it throw you off! Approximately 45% of patients with chronic low back pain suffer from “facet syndrome” (FS) in which the facets are the low back pain generator.
There are many conditions that give rise to FS. Some of these include the straining of the surrounding joint capsule (the capsule holds the joint securely together), joint hypomobility (reduced motion in the joint), a synovial cyst (similar to a ganglion on the back of the wrist but its located inside the joint), and degeneration (also called osteoarthritis—the wearing out type of arthritis).
Because facet syndrome can accompany other conditions, a doctor of chiropractic must evaluate each patient individually and manage each person appropriately. In “pure” facet syndrome, pain rarely ever passes the level of the knee and does not cause neurological loss (weakness, loss of reflex, etc.). It can create numbness but usually NOT beyond the knee. Pain is usually not worsened by hip movements such as straight leg raise or hip rotation.
The facet joint’s “job” (at least in part) is to limit or guard twisting movements in the upper lumbar/low back region, and the lower lumbar facets are shaped to limit motion when bending forwards and backwards. Facet joints are unique because they are innervated by specific nerves that can be blocked by injecting an anesthetic agent to determine if the facet (and its innervating nerve) is the main source of pain. The surrounding capsule around the facet joint contains mechanoreceptors (cells that detect movement) and nociceptors (cells that detect pain) that fire when the facet joint is compressed/jammed or over-stretched. These nociceptors can become “hypersensitized” (very irritable) when they remain inflamed over time.
In many patients, injury to a facet joint is the result of many microtraumas over a period of time and not one single isolated event. For example, repeatedly bending backwards, twisting, and leaning to one side can stretch the joint capsule and fatigue it until some capsular tissues finally “give” and it inflames which generates pain.
These joints commonly become arthritic with age, which is one reason people over 50-60 years old commonly present with FS. Osteoarthritis results in a narrowing of the joint space and causes a more permanently “jammed” joint. This is one reason many elderly people walk partially bent over—as bending forwards opens the facet joints and “feels good!”
The good news is that chiropractic manipulation is a highly effective treatment for facet syndrome, and most patients feel much better within the first or second week of care (often within three to five visits).