THE FACET SYNDROME
Written by Dr. Pankaj Suranje
���� The facet joints are a pair of joints in
the posterior aspect of the spine. Although these joints are most commonly
called the facet joints, they are more properly termed the zygapophyseal joints
(abbreviated as Z-joints), a term derived from the Greek roots zygos,
meaning yoke or bridge, and physis, meaning outgrowth. The term facet
joint is a misnomer because the joint occurs between adjoining zygapophyseal
processes, rather than facets, which are the articular cartilage lining small
joints in the body (eg, phalanges, costotransverse and costovertebral joints).
This joint is also sometimes referred to as the apophyseal joint or the
posterior intervertebral joint.
As is true of any synovial joint, the
facet-joint is a potential source of pain. In fact, the facet-joint is one
of the most common sources of low back pain (LBP). The first discussion of
the facet-joint as a source of LBP was by Goldwaith in 1911. (1) In 1927, Putti (2) illustrated osteoarthritic changes of facet-joints in 75
cadavers of persons older than 40 years. In 1933, Ghormley(3)�
coined the term facet syndrome, suggesting that hypertrophic changes
secondary to osteoarthritis of the zygapophyseal processes led to lumbar nerve
root entrapment, which caused LBP. In the 1950s, Harris
and Mcnaz (4) and McRae (5) determined that the etiology of facet-joint degeneration
was secondary to intervertebral disc degeneration. Hirsch et al were later able to reproduce LBP with
injections of hypertonic saline solution into the facet-joints, thus affirming
the role of the facet-joints as a source of LBP (6)
The spine is composed of a series of functional units. Each unit
consists of an anterior segment, which is made up of 2 adjacent vertebral
bodies and the intervertebral disc between them, and the posterior segment,
which consists of the laminae and their processes. One joint is formed between the
2 vertebral bodies, whereas the other 2 joints, known as the facet-joints, are
formed by the articulation of the superior articular processes of one
vertebra with the inferior articular processes of the vertebra above. Thus, the
facet-joints are part of an interdependent functional spinal unit consisting of
the disc-vertebral body joint and the 2 facet-joints, with the facet-joints
paired along the entire posterolateral vertebral column.(7)
Facet joints are well innervated by the medial
branches of the dorsal rami. In the thoracic and lumbar spine, the facet joints
are in�nervated by medial branches of the dorsal rami of the spinal nerves
except at L5 lev�el (8).
After the medial branch splits off from the dorsal ramus, it courses caudally
around the base of the superior articular process of the level below toward
that level's Z-joint (e.g., the L2 medial branch wraps around the L3 superior
articular process to approach the L2-L3 facet-joint). The medial
branch then continues in a groove between the superior articular process
and transverse process (or, in the case of the L5 medial branch, between the
superior articular process of S1 and the sacral ala of S1, which is the
homologous structure to the transverse processes of the lumbar vertebrae). As
it makes this course, the medial branch is held in place by a
ligament joining the superior articular process and the transverse process,
termed the mamillo-accessory ligament (MAL).
The MAL is so named because it adjoins
the mamillary process of the superior articular process to the accessory
process of the transverse process. The MAL is clinically important because
it allows precise location of the medial branch of the dorsal ramus using only
bony landmarks, which is essential for fluoroscopically guided procedures.
After passing underneath the MAL, the medial branch of the dorsal
ramus gives off 2 branches to the nearby facet-joints. One branch innervates
the facet-joint of that level, and the second branch descends caudally to the
level below. Therefore, each medial branch of the dorsal ramus innervates 2
joints�that level and the level below (e.g., the L3 medial branch innervates
the L3-L4 and L4-L5 facet-joints). Similarly, each facet-joint is innervated by
the 2 most cephalad medial branches (e.g., the L3-L4 facet-joint is innervated
by the L2 and L3 medial branches). Medial branch also innervates the
multifidus, interspinales, and intertransversarii mediales muscles, the
interspinous ligament, and, possibly, the ligamentum flavum. (9)
This has several important
clinical implications. First, pain relief from anesthetizing the medial
branch does not necessarily implicate the facet-joints as the primary pain
generator, because one of the other structures innervated by the medial branch
may have been the pain generator. Second, denervation of the medial branch
by RFA may affect the nerve supply to the multifidus muscle. This is
important because lumbosacral radiculopathy is often another consideration in
the differential diagnosis of LBP.
The L5 dorsal ramus divides
into me�dial and lateral branches, with the medi�al branch continuing medially,
innervat�ing the lumbosacral joint.
As with any synovial joint, degener�ation, inflammation and injury
of facet joints can lead to pain upon joint motion. Pain leads to restriction
of motion, which eventually leads to overall physical decon�ditioning.
Irritation of the facet joint in�nervation in itself also leads to secondary
muscle spasm. It has been assumed that degeneration of the disc would lead to
as�sociated facet joint degeneration and sub�sequent spinal pain. These
assumptions were based on the pathogenesis of degen�erative cascade in the
context of a three joint complex that involves the articula�tion between two
vertebrae consisting of the intervertebral disc and adjacent fac�et joints, as
changes within each mem�ber of this joint complex will result in changes in
(10, 11). It was also the view
of Vernon-Roberts and Pi�rie (12) that disc degeneration causes os�teophyte
formation and facet joint chang�es, because facet joints at relatively normal
disc levels are either normal or only slight�ly degenerate.
The Facet joint is a common pain
generator in the lower back. The 2 common mechanisms for this generation of
pain are either (1) direct, from an arthritic process within the joint itself,
or (2) indirect, in which overgrowth of the joint (e.g., facet joint
hypertrophy or a synovial cyst) impinges on nearby structures. (13)
The Facet-joints are diarthrodial joints
with a synovial lining, the surfaces of which are covered with hyaline
cartilage, which is susceptible to arthritic changes and arthropathies.
Repetitive stress and osteoarthritic changes to the facet joint can lead to
zygapophyseal hypertrophy. Like any synovial joint, degeneration, inflammation,
and injury can lead to pain with joint motion, causing restriction of motion
secondary to pain and, thus, deconditioning. In addition, facet-joint
arthrosis, particularly trophic changes of the superior articular process, can
progress to narrowing of the neural foramen. In addition, as is the case for
any synovial joint, the synovial membrane can form an outpouching and, thus, a cyst. Facet-joint cysts are most
commonly seen at the L4-L5 level (65%), but they are also seen at the L5-S1
(31%) and L3-L4 (4%) levels. These synovial cysts can be clinically
significant, particularly if they impinge on nearby structures (e.g., the
exiting nerve root).
Facet-joint hypertrophy or a synovial
cyst can also contribute to lateral and central lumbar stenosis, which can lead
to impingement on the exiting nerve root. Thus, facet-joint pain can
occasionally produce a pain referral pattern that is indistinguishable from
Numerous other causes, including rheumatoid arthritis, ankylosing
spondy�litis and capsular tears, etc., also have been described as sources of
facet joint pain (14).
Facet joints have been implicated as responsible for spinal pain
in 15% to 45% of patients with low back pain (15), 54% to
67% of patients with neck pain and 48% of patients with thoracic pain
in controlled stud�ies. These figures were based on respons�es to controlled
diagnostic blocks of these joints, in accordance with the criteria es�tablished
by the International Associa�tion for the Study of Pain
Establishing a diagnosis of lumbosacral
facet syndrome is difficult because the findings are nonspecific and
correlation between the history and physical examination findings is poor.
However, obtaining a detailed history and performing a physical examination
help rule out other entities and assist with guiding the examiner in
establishing the diagnosis of facet-joint�mediated LBP.
Although no single sign or symptom
is diagnostic, Jackson et al demonstrated that the combination of the following
7 factors was significantly correlated with pain relief from an
intra-articular facet-joint injection
1. Older age
2. Previous history
3. Normal gait
4. Maximal pain
with extension from a fully flexed position
5. The absence of
6. The absence of
7. The absence of
exacerbation with a Valsalva maneuver
pathology should be considered if the patient describes nonspecific LBP with a
deep and achy quality that is usually localized to a unilateral or bilateral
referral areas for facet-joint�mediated pain are flank pain, buttock pain
(often extending into the posterior thigh, but rarely below the knee), pain
overlying the iliac crests, and pain radiating into the groin.
The pain is
often exacerbated by twisting the back, by stretching, by lateral bending, and
in the presence of a torsional load. Some patients describe their pain as worse
in the morning, aggravated by rest and hyperextension, and relieved by repeated
motion. Often, this lumbosacral facet syndrome may occur after an acute injury
(e.g., extension and rotation of the spine), or it
may be chronic in nature.
lumbar spine pathologies such as disc herniation, facet-joint�mediated pain
likely will not worsen with an increase in intra-abdominal and thoracic
pressure. Therefore, worsening of pain with coughing, laughing, or a Valsalva
maneuver is suggestive that the facet-joint is not the primary pain generator.
examination: Sensory examination (i.e., light touch and pinprick in a
dermatomal distribution) findings are usually normal in persons with
� Muscle stretch
reflexes: Patients with facet-joint�mediated LBP usually have normal muscle
stretch reflexes. Radicular findings are usually absent unless the patient has
nerve root impingement from bony overgrowth or a synovial cyst.
leg�raise test: This maneuver is usually normal for facet-joint�mediated pain.
However, if facet-joint hypertrophy or a synovial cyst encroaches on the intervertebral
foramen, causing nerve root impingement, this maneuver may elicit a positive
It has been postulated that for any structure to be
deemed a cause of back pain, the structure should have been shown to be a
source of pain in patients, using diagnostic techniques of known reliability
and validity (25). The
diagnostic blockade of a structure with a nerve supply with the ability to
generate pain can be performed to test the hypothesis that the target structure
is a source of a patient�s pain
The choice between intraarticular blocks and medial
branch blocks is to some extent preference and training of the physician.
However, various considerations apply in choosing either intraarticular
injection or medial branch. Intraarticular injections are more difficult and
time consuming than nerve blocks because they require accurate placement of the
needle within the joint cavity with care not to over distend the joint. In
contrast, medial branch blocks are expeditious and carry no risk of over
distention. Furthermore, at times joint entry may be impossible because of the
severe age related changes or post traumatic arthropathy; no such processes
affect access to the nerves .Significant leakage of intraarticular injected
fluid into epidural space and spillage over to the nerve roots has been
described. With appropriate care this is minimal with medial branch blocks.
Finally, intraarticular blocks are appropriate if intraarticular therapy is
proposed but if radiofrequency therapy is proposed, medial branch blocks become
the diagnostic procedure of choice. In addition, in the past only
intraarticular injections were considered as therapeutic. However, recent
evidence has shown that medial branch blocks have better evidence for the
therapeutic effectiveness than intraarticular blocks (17).
Valid information is only obtained by performing controlled
blocks, either in the form of placebo injections of normal saline or
comparative local anesthetic blocks, in which on two separate occasions, the
same joint is anesthetized using local anesthetics with different durations of
action. . In a double-block protocol, the patient is given an injection
with a short-acting anesthetic (e.g., lidocaine) and records the duration of
pain relief in a diary. On a follow-up visit (typically 1-2 wk later), a second
injection is performed, using an anesthetic with a different duration of action
(e.g., bupivacaine, which has a longer half-life than lidocaine), and the
patient again should chart pain relief in a diary. A patient is diagnosed as
having a positive block if they receive pain relief (typically >80%) for
both injections for a length of time corresponding to the duration of action of
the medication.(18,19,20) Given the dual innervation of each
Z-joint, one must anesthetize or block the cephalad and subadjacent medial
branches (eg, anesthetize the L3 and L4 medial branches for the L4-L5 Z-joint).
Injections are diagnostic if patients report significant relief of symptoms,
usually at least a 50% reduction in pain.
Laboratory studies are not generally necessary for the diagnosis
of lumbosacral facet joint syndrome.
Plain radiographs are traditionally ordered as the initial step in
the workup of lumbar spine pain. The main purpose of plain films is to
determine underlying structural pathologic conditions. These studies are not
generally recommended in the first month of symptoms in the absence of red
flags. An exception to this would be if the low back symptoms are related to a sports injury and a fracture is suggested.
Three views are commonly obtained, including an anteroposterior
(AP), lateral, and oblique; however, the utility of oblique views has been
Plain radiographs may reveal degenerative changes, but these
findings have not been found to correlate with facet-joint�mediated pain.
Bone scanning can be helpful when a tumor, infection, or fracture
(occult or traumatic) is suggested.
Bone scanning is not usually indicated in the initial workup, and
the results are normal in persons with lumbosacral facet joint syndrome.
Bone scan findings have not been found to correlate with
Computed tomography (CT) scanning
Generally, CT scanning is not necessary unless other bony
pathology (eg, fracture) must be excluded.
A CT scan of the lumbosacral spine provides excellent anatomic
imaging of the osseous structures of the spine, especially to rule out
fractures or arthritic changes. Single-photon emission CT (SPECT) images may
offer better resolution if spondylolysis is suggested.
With facet-joint pathology, one may find arthritic changes in the
facet-joints and degenerative disc disease; however, facet-joint pathology is
also frequently seen in asymptomatic patients, and, therefore, abnormal
findings on a CT scan are not diagnostic.
Despite the excellent imaging of the bony anatomy of the
facet-joint, CT scans are not useful for the diagnosis of the facet-joint as a
pain generator. For example, Schwarzer et al found no correlation between
facet-joint pathology on a CT scan and those patients who responded to
diagnostic facet-joint blocks. (21) .Therefore, the
correlation of an abnormal facet-joint anatomy as observed on CT scans with
true facet -joint�mediated pain is poor.
Magnetic resonance imaging (MRI)
In general, MRI is not indicated for the evaluation of
The main utility of MRI is for excluding pathologies other than
facet-joint arthropathy, because many degenerative changes in the facet-joint
are asymptomatic. Similarly, true facet-joint�mediated pain may be present
despite a normal MRI examination.
MRI provides detailed anatomic images of the soft structures of
the spine, such as the intervertebral discs, which often show degenerative
changes before facet-joint pathology. (22)
MRI also may illustrate nerve root entrapment secondary to
facet-joint hypertrophy or a synovial cyst and may help visualize the
intervertebral foramen; however, facet-joint pathology may be present despite
normal imaging study findings.
MRI is particularly useful for the evaluation of a synovial cyst
emanating from a facet-joint and for distinguishing a synovial cyst from other
abnormalities. Gadolinium enhancement is useful in the evaluation of a
potential synovial cyst. Also helpful is to make the radiologist aware that a
synovial cyst is part of the differential diagnosis because this entity is
Electro diagnostic studies, such as nerve conduction studies and
needle EMG, are not usually indicated for possible lumbosacral facet
syndrome. However, these studies should be considered if the history and
physical examination findings suggest nerve root impingement or if the
diagnosis remains unclear.
Persons with facet-joint pathology typically present with normal
sensory and motor examination findings; however, some patients describe the
pain as radiating in nature and others report a positive straight leg�raise
test result. Thus, electro diagnostic testing may be helpful for excluding
other causes of pain, such as radiculopathy.
RFA of the medial branch of the dorsal ramus affects the innervation
of not only the facet-joint, but also the multifidus muscle. Normally,
denervation potentials in the multifidus muscles in the setting of LBP are most
commonly associated with lumbosacral radiculopathy. In the setting of a patient
who has had previous RFA, however, the denervation potential is likely
secondary to denervation from the procedure and not a radiculopathy.
The requirements for safe use of therapeutic
interventions include a sterile operating room or a procedure room, appropriate
monitoring equipment, radiological equipment; special instruments based on
technique, sterile preparation with all the resuscitative equipment, needles,
gowns, injectable drugs, intravenous fluids, anxiolytic medications, and
trained personnel for preparation and monitoring of the patients. Minimum
requirements include history and physical examination, informed consent, and
appropriate documentation of the procedure.
Facet joint pain may be managed by intraarticular
injections, medial branch blocks, or neurolysis of medial Branches (Facet
�Based on the
available literature and scientific application, the most commonly used
formulations of long-acting steroids, which include methylprednisolone
(Depo-Medrol), triamcinolone diacetate (Aristocort), triamcinolone acetonide
(Kenalog), and betamethasone acetate and phosphate mixture (Celestone
Soluspan), appear to be safe and effective (23)
Based on the present literature, it appears that if
repeated within 2 weeks, betamethasone may be the best choice in avoiding side
effects; whereas, if treatment is carried out at 6-week intervals or longer,
any one of the 4 formulations will be safe and effective.
�Facet Joint Injections and Medial Branch
♦ In the diagnostic phase, a patient may receive 2
procedures at intervals of no sooner than 1 week or preferably 2 weeks.
♦ In the therapeutic phase (after the diagnostic is
completed), the suggested frequency would be 2�3 months or longer between
injections, provided that >50% relief is obtained for 6 weeks.
♦ If the interventional procedures are applied for
different regions, they may be performed at intervals of no sooner than 1 week
or preferably 2 weeks for most types of procedures. It is suggested that
therapeutic frequency remain at 2 months for each region. It is further
suggested that all regions be treated at the same time, provided all procedures
can be performed safely.
♦ In the treatment or therapeutic phase, the
interventional procedures should be repeated only as necessary according to the
medical necessity criteria, and it is suggested that these be limited to a
maximum of 4 to 6 times for local anesthetic and steroid blocks over a period
of 1 year, per region.
♦ Under unusual circumstances with a recurrent
injury or cervicogenic headache, procedures may be repeated at intervals of 6
weeks after stabilization in the treatment phase.
Neurotomy (Facet denervation)
♦ The suggested frequency would be 3 months or
longer (maximum of 3 times per year) between each procedure, provided that >
50% relief is obtained for 10 to 12 weeks.
♦ The therapeutic frequency for medial branch
neurotomy should remain at intervals of at least 3 months for each region. It
is further suggested that all regions be treated at the same time, provided all
procedures are performed safely.
Contraindications include ongoing bacterial infection,
possible pregnancy, bleeding diathesis, and anticoagulant therapy. Precautions
are warranted in patients with anticoagulant or antiplatelet therapy, diabetes
mellitus and artificial heart valves.
Always obtain informed consent for any
interventional procedure. In addition, patients must be informed of the risks,
benefits, and potential outcomes associated with the procedure.
Patients with LBP who demonstrate red
flags, such as unexplained weight loss, fever, and chills, should be further
evaluated to rule out malignancy or occult infectious processes.
Interventional procedures with
anesthetics and corticosteroids, can lead to transient lower-extremity
weakness, insomnia, headache, fluid and electrolyte disorders (especially in patients
with congestive heart failure), GI upset, bone demineralization, and impaired
glucose tolerance (patients with diabetes). Less common effects are mood
swings, increased appetite, and, the most serious, adrenocortical
insufficiency. Dural puncture can lead to infection and an increased incidence
JE. The lumbosacral articulation: an explanation of many cases of
"lumbago," "sciatica" and "paraplegia". Boston Med Surg J. 1911;164:365-72
Putti V. New conceptions in the pathogenesis of sciatic pain. Lancet. 1927; 2:53-60.
Ghormley RK. Low back pain with special reference to the
articular facets, with presentation of an operative procedure. JAMA. 1933; 101:1773-7.
RI, Macnab I. Structural changes in the lumbar intervertebral discs; their
relationship to low back pain and sciatica. J Bone Joint Surg Br. May 1954; 36-B (2):304-22.
DL. Asymptomatic intervertebral disc protrusions. Acta radiol. Jul-Aug 1956;46(1-2):9-27
Hirsch C, Ingelmark B E, Miller M. The anatomical basis for low
back pain. Studies on the presence of sensory nerve endings in ligamentous,
capsular and intervertebral disc structures in the human lumbar spine. Acta Orthop Scand. 1963;33:1-17
�Bogduk N. The zygapophysial joints. In Clinical Anatomy of the
Lumbar Spine and Sacrum, Third edition. Churchill Living�stone, New York, 1997,
Dreyfuss P, Schwarzer AC, Lau P et al. Specificity of
lumbar medial branch and L5 dorsal ramus blocks. Spine 1997; 22:895-902.
Dreyfuss P, Schwarzer AC, Lau P et al. Specificity of lumbar
medial branch and L5 dorsal ramus blocks. Spine 1997; 22:895-902.
Fujiwara A, Tamai K, Yamato M et al. The relationship
between facet joint osteoar�thritis and disc degeneration of the lum�bar spine:
An MRI study. Eur J Spine 1999; 8:396-401
11. Fujiwara A, Lim T, an H et al. The effect of disc degeneration and
facet joint os�teoarthritis on the segmental flexibility of the lumbar spine.
Spine 2000; 25:3036-3044
Vernon-Roberts B, Pirie CJ. Degenerative changes in the intervertebral
discs of the lumbar spine and their sequelae. Rheum Rehabil 1977; 16:13-21.
13. Cohen SP, Raja
SN. Pathogenesis, diagnosis, and treatment of lumbar zygapophysial (facet)
joint pain. Anesthesiology. Mar 2007;
14. Bogduk N. Low back pain. In Clinical Anatomy of the Lumbar Spine
and Sa�crum, ed. 3. Churchill Livingstone, New York, 1997; pp 187-214.
Manchikanti L, Singh V, Pampati V et al. Evaluation of the
relative contributions of various structures in chronic low back pain. Pain
Physician 2001; 4:308-316
16. Jackson RP,
Jacobs RR, Montesano PX. 1988 Volvo award in clinical sciences. Facet
joint injection in low-back pain. A prospective statistical study. Spine. Sep 1988;
Boswell MV, Colson JD, Sehgal N, Dunbar E, Epter R. Systematic
review of therapeutic facet joint interventions in chronic spinal pain. Pain Physician 2007; 10:229-253.
Bogduk N, McGuirk B. Management
of Acute and Chronic Neck Pain. Evidence- Based Approach. Elsevier,
Bogduk N. International Spinal Injection Society guidelines for
the performance of spinal injection procedures. Part 1: Zygapophyseal joint
blocks. Clin J Pain 1997;
Sehgal N, Shah RV, McKenzie-Brown AM, Everett CR. Diagnostic
utility of facet (zygapophysial) joint injections in chronic spinal pain: A
systematic review of evidence. Pain
Physician 2005; 8:211-224.
Schwarzer AC, Wang SC, O'Driscoll D, et al. The
ability of computed tomography to identify a painful zygapophysial joint in
patients with chronic low back pain. Spine. Apr 15 1995;20(8):907-12
22. D'Aprile P,
Tarantino A, Jinkins JR, Brindicci D. The value of fat saturation
sequences and contrast medium administration in MRI of degenerative disease of
the posterior/perispinal elements of the lumbosacral spine. Eur Radiol. Feb 2007;17(2):523-31
Rozenberg S. Glucocorticoid therapy in common lumbar spinal
disorders. Rev Rhum Engl Ed 1998;
Interventional Techniques: Evidence-based Practice Guidelines in
the Management of Chronic Spinal Pain.
Pain Physician 2007; 10:7-111 � ISSN 1533-3159
Pang WW, Mok MS, Lin ML, Chang DP, Hwang MH. Application of
spinal pain mapping in the diagnosis of low back pain�analysis of 104 cases. Acta Anaesthesiol Sin 1998; 36:71-74.