Chapter 46 Facet Syndrome: Facet Joint Injections, Medial Branch Blocks, and Radiofrequency Denervation Flashcards Preview

Essentials of Pain Medicine > Chapter 46 Facet Syndrome: Facet Joint Injections, Medial Branch Blocks, and Radiofrequency Denervation > Flashcards

Flashcards in Chapter 46 Facet Syndrome: Facet Joint Injections, Medial Branch Blocks, and Radiofrequency Denervation Deck (55):

causes of neck and LBP

The etiology is usually multifactorial, including muscles, ligaments, discs, nerve roots, and zygapophysial
(facet) joints.


The zygapophysial joint (facet
joint) is a potential source of

neck, shoulder, mid back, low
back, and leg pain. It is also a potential source for headaches.


facet joints

paired structures that sit posterolaterally to the vertebral body, and along with the intervertebral disc, comprise the three-joint complex. Facet joints are true synovial joints formed from the superior articular process of one vertebra and the inferior articular process of the vertebra


Function of the facet joints

This complex works
together to stabilize the joint and allow for different movements depending on the level.


The volume capacity of the joints

1 to 1.5 ml and
0.5 to 1.0 ml in the lumbar and cervical regions, respectively.


The lumbar facets vary in angle but are aligned

lateral to the sagittal plane, with the inferior articular process facing anterolaterally and the superior articular process facing posteromedially


The upper lumbar
facet joints are oriented

more parallel to the sagittal plane
(26–34 degrees), while the lower lumbar facets tend to be
more closely aligned with the coronal plane.


The thoracic facets are oriented

the most vertically oriented joints, allowing for
lateral flexion without axial rotation.


The C2–C3 joint, the most frequent cervical facet pain generator, is aligned approximately

70 degrees from the sagittal plane and 45 degrees from the
axial plane, which inhibits rotation and anchors the C2 vertebra as a rotational pivot for the atlantoaxial joint (C1–C2


The area of greatest mobility in the cervical spine is at

C5–C6, the second most affected cervical facet joint,
which is where the cervical facets transition to their posterolateral position.


The medial branch

the terminal division of the posterior ramus that provides sensory innervation to the facet joint.


The medial branch divisions

This smaller posterior division of
the nerve root is divided into lateral, intermediate, and medial branches. The lateral branch in the lumbar region
provides innervation to the paraspinous muscles, skin, and
sacroiliac joint, while the small intermediate branch innervates
the longissimus muscle. The medial branch is the largest of the divisions.


medial branch division of the medial branch innervates

It innervates the facet joint, multifidus muscle, interspinal muscle and ligament, and the periosteum of the neural arch.


Each facet joint is innervated by

two medial branches, the medial branch at the same level and the level above (i.e., the L4–L5 facet joint is innervated by the L3 and L4 medial branches)


The position of the medial branch in the lumbar spine

It divides from the posterior primary ramus and wraps around the transverse process of the level below at the
junction of the transverse process and superior articular
process (i.e., the L3 medial branch lies on the transverse
process of L4). The nerve traverses the dorsal leaf of
the intertransverse ligament of the transverse process
and courses underneath the mamilloaccessory ligament,
splitting into multiple branches as it crosses the vertebral lamina


The mamilloaccessory ligament can
become calcified and be a source of

nerve entrapment, especially
at L5.


The main variation in the lumbar spine is at L5

where it is the primary dorsal ramus itself that is
amenable to blockade


in the thoracic spine the medial branches assume a courses

The nerve swing laterally to
circumvent the multifidus muscle, thereby removing
multifidus contraction as a means of needle confirmation
prior to denervation. The superolateral corner of the transverse process is the most consistent point for blockade


How many cervical nerve roots?

There are eight cervical nerve roots, which exit above the corresponding vertebral body


C3–C4 through the C7–T1 joints innervation from the medial

the C3–C4 through
the C7–T1 joints receive innervation from the medial
branches at the same level and the level above. The
nerves curve around the waist of the articular pillars,
except at C7 and C8, where the anatomy is more variable.


The majority of the innervation of the C2–C3 joint comes from the

dorsal ramus of C3.


The C3 dorsal ramus divides into

two separate medial branches,
the larger of which is known as the third occipital nerve


The C2 dorsal ramus divides into

up to five branches, the
largest of which is the greater occipital nerve.


involving branches of the C2 and C3 dorsal rami are a
common source of

occipital headaches


The facet joints contain

rich supply of encapsulated, unencapsulated, and free nerve endings. established the presence of Substance P and calcitonin gene-related peptide reactive nerve fibers in cadaveric facets. Inflammatory mediators, including prostaglandins, interleukin-6, and tumor necrosis factor-a, have been demonstrated in the facet cartilage


facet arthropathy and facet-mediated pain pathopyisiology

years of repetitive
strain, intervertebral disc degeneration, and minor trauma
are more commonly implicated.


the greatest degree of motion and strain in the

lumbar spine occurs in
the lowest two facet joints (L4–L5 and L5–S1). At these
joints, strain is maximized by forward flexion. In the most
caudad joints (L3–S1), the greatest degree of strain is
observed with contralateral bending, whereas the opposite
is seen at L1–L2 and L2–L3.


The two most caudal facet joints are associated with the greatest degree of degenerative disc disease,
and are most commonly affected.

(L4–5 and L5–S1)


The most common presentation of trauma-induced facet pain is

whiplash injury


The most reliable method to determine
facetogenic pain is with

One limiting factor
in determining the true incidence of facet pain is that the diagnosis cannot be made by historical, physical exam, or radiologic findings. The most reliable method to determine facetogenic pain is with image-guided medial branch
or intra-articular facet joint blocks


In the lumbar region, the upper facet joints tend to refer pain into the

flank, hip and
upper lateral thigh


For lower levels, pain is generally experienced in the

posterolateral thigh and occasionally
the calf.


In the cervical spine, upper facet arthropathy usually
manifests as pain felt in the

posterior upper neck and occipital region.


Pathology involving middle cervical
facet joints tends to radiate into the

lower neck and supraclavicular region


lower cervical facetogenic pain
typically causes pain in the

base of the neck and scapular region.


limited utility in the diagnosis of
facet-mediated pain

radiologic examination


diagnostic MBBs

volumes as small as 0.5 ml cover 6 cm2 of tissue. Hence,
the intermediate and lateral branches are likely to be anesthetized with typical injection volumes, thereby blocking afferent transmission from portions of the paraspinous musculature and sacroiliac joint


excessive volumes of local anesthetic solution

can rupture the joint capsule, leading to spread into the intervertebral
foramen epidural space, and paraspinous musculature.


Both medial branch and intra-articular blocks are associated
with high rates of

false-positive results.


Potential causes of false-positive blocks include

response, sedation, excessive superficial local anesthesia,
and the spread of local anesthetic to other pain-generating


the use of sedation for
diagnostic blocks should be limited

as even benzodiazepines
can lead to muscle relaxation and interfere with a
patient’s ability to assess pain relief.


Techniques to Reduce False-Positive Rates for
Lumbar Medial Branch Blocks

1. Avoid the use of sedation and analgesics.
2. Use injectate volumes of #0.5 ml.
3. Limit volume of skin local anesthesia.
4. Aim for lower target point on transverse process.
5. Use a single-needle approach.
6. Consider use of comparative local anesthetic blocks.


One of the principal causes of false-negative blocks is

thought to be vascular uptake. The most reliable means to detect vascular uptake is with real-time fluoroscopy. Other potential causes of false-negative blocks are failure to discern between baseline and procedure-related pain, and missing a target


conservative management for spinal pain

There is strong evidence for
nonsteroidal anti-inflammatory drugs and acetaminophen. Antidepressants
and muscle relaxants have also been shown to be effective. physical activity and weight loss are likely to benefit BP patients. Spinal manipulation is superior to sham treatment for
acute and chronic spinal pain. Acupuncture also appears effective for
spinal pain,


The most commonly performed treatment for facetmediated
pain is

RF denervation


The medial branch is denervated by

placing the active
tip of a RF needle at the location of the nerve


The medial branch is denervated for the lumbar region

the active tip is optimally positioned at the junction
of the transverse process and lateral neck of the superior
articular process in an orientation parallel to the nerve


The medial branch is denervated In
the cervical region

the active tip should be placed along the
center of the articular pillar at most levels


Sensory stimulation

usually performed prior to denervation, with most experts recommending a threshold of no more than 0.5 volts.


Motor stimulation

considered a safety measure to ensure
adequate distance from motor fibers, though the elicitation
of multifidus muscle contraction has also been used to guide needle placement


Prior to denervation, local anesthetic
with or without steroid can be injected to

reduce procedure related pain, enhance lesion size, and prevent neuritis


duration of analgesia following RF denervation

varies widely
between studies, with most demonstrating between 6 months
and 1-year relief


Surgery is occasionally done for facet pain

inadvertently transect the medial
branch during pedicle screw placement, which can provide
some pain relief.



The most feared risk of RF denervation is thermal damage
to the ventral nerve root due to incorrect needle placement,
which is rare when motor stimulation is utilized. Post denervation
neuritis is the most common complication. Some patients describe transient numbness or dysesthesias, which are usually minor
and self-limting


neuritis can be reduced even further with

corticosteroid administration

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