Injuries and Diseases
|Bones of the spine articulate anteriorly
by intervertebral disks and posteriorly by paired joints.
These posterior paired joints are commonly termed facet
joints, more formally termed zygapophyseal joints. Facet
joints are true synovial joints, with a joint space, hyaline
cartilage surfaces, a synovial membrane, and a fibrous
capsule. Two medial branches of the dorsal rami innervate
the facet joints. Medial branches of the lumbar dorsal
rami issue from their respective intervertebral foramina,
cross the superior border of the transverse process, and
then run medially around the base of the facet joint before
innervating the joints.
In recent studies, nociceptive substance P immunoreactive
nerve fibers and autonomic nerves have been identified
in the lumbar facet joint capsule and synovial folds.
Douglas et al identified substance P immunoreactive nerve
fibers in erosion channels extending through the subchondral
bone and calcified cartilage into the articular cartilage.
Giles and Harvey identified them in the inferior recess
capsule and synovial folds, whereas Ashton et al identified
them running freely in the facet capsule stroma. Gröblad
et al demonstrated sparsely distributed substance P immunoreactive
nerve fibers in facet joint plical tissue.
The presence of nociceptive nerve fibers in the various
tissue structures of facet joints and the presence of
autonomic nerves suggest that these structures may cause
pain under increased or abnormal loads. Substance P is
a well-known inflammatory mediator that may sensitize
nociceptors to them and other mediators, resulting in
Like other joints, the facet joints consist of bone, cartilage,
synovial tissue, and menisci that are rudimentary invaginations
of the joint capsule. In the synovial fluid of patients
with rheumatoid arthritis, osteoarthritis, or traumatic
joint disease, increased levels of prostaglandins have
been measured and implicated as an important cause of
pain. Prostaglandin, a known inflammatory mediator, is
also released from facet joints.
Biomechanically, facet joints assume a prominent role
in resisting stress, and their importance is well established.
A cadaveric study by Adams and Hutton demonstrated that
the facet joints resist most of the intervertebral shear
force and share in resisting the intervertebral compressive
force, albeit only in lordotic postures. In rotation of
the spine, the facet capsular ligaments are by far the
most strained among the various spinal ligaments. They
protect the intervertebral disks by preventing excessive
In the US: The prevalence of facet joint pain in the general
population or in those with acute back pain has not been
investigated. The reported rate of facet joint pain for
patients with chronic LBP ranges from 4-75%. The reported
prevalence seems to be a function of the size of the sample
studied and the conviction of the authors.
Three studies report the prevalence of lumbar facet joint
pain among chronic LBP patients based on 100% relief of
pain using less than 2 mL of intra-articular diagnostic
injection. In 1988, Jackson et al reported 7.7% of 454
patients with chronic LBP had 100% relief with diagnostic
injection. In 1991, Carette et al reported that 11 (5.8%)
of 190 patients experienced complete relief of symptoms
with a single lidocaine injection. In 1994, Schwarzer
et al reported that 7 (4%) of 176 patients reported 100%
relief. This latter study was more stringent than the
former in that Schwarzer et al performed a second confirmatory
block with bupivacaine, documenting longer relief of pain
commensurate with the longer half-life of the local anesthetic.
When less stringent criteria are used, higher prevalences
are reported. In 1988, Moran et al reported relief in
9 (16.7%) of 45 patients using 1.5 mL of bupivacaine.
Pain provocation followed by pain relief with local anesthetic
was used as the diagnostic criterion. In 1992, Schwarzer
et al reported relief in 9 (9.7%) of 92 patients using
50% reduction of pain and double-block screening with
lidocaine and confirmatory bupivacaine block. In a separate
investigation, they reported a prevalence of 26 (15%)
of 176 patients using the same diagnostic criteria. In
yet another study, Schwarzer et al reported 23 (40.3%)
of 57 patients obtained 50% or more pain relief with bupivacaine
but no relief with saline control injection. A 2004 study
by Manchikanti et al reported a lumbar facet prevalence
rate of 27% using controlled comparative local anesthetic
blocks of the dorsal median nerves.
Higher prevalence rates are reported when control blocks
are not used. In 1984, Raymond and Dumas reported a 16%
prevalence rate using a strict intracapsular technique
but no control block. In 1992, Revel et al reported 22
(55%) of 40 subjects had 75% or more relief of pain and
17 (42.5%) of 40 patients had greater than 90% relief
of their pain with a single intra-articular lidocaine
As seen from these data, reports of prevalence are a function
of the investigators' choice of selection criteria. Studies
requiring the most stringent 100% relief of symptoms after
a diagnostic block report a 4-7.7% prevalence rate of
facet joint pain among chronic LBP patients. Studies using
double blocks requiring 50% relief report prevalence rates
of 9-15%. Numerous other studies using a single diagnostic
block report prevalence rates from 16-75%.
Cervical facet pain is often related to whiplash type
of injuries in the cervical spine and is more often a
post-traumatic finding than in the lumbar spine.