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

Question 1

causes of neck and LBP

Answer 1

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

Question 2

The zygapophysial joint (facet

joint) is a potential source of

Answer 2

neck, shoulder, mid back, low

back, and leg pain. It is also a potential source for headaches.

Question 3

facet joints

Answer 3

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
above

Question 4

Function of the facet joints

Answer 4

This complex works

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

Question 5

The volume capacity of the joints

Answer 5

1 to 1.5 ml and

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

Question 6

The lumbar facets vary in angle but are aligned

Answer 6

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

Question 7

The upper lumbar

facet joints are oriented

Answer 7

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

Question 8

The thoracic facets are oriented

Answer 8

the most vertically oriented joints, allowing for

lateral flexion without axial rotation.

Question 9

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

Answer 9

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

Question 10

The area of greatest mobility in the cervical spine is at

Answer 10

C5–C6, the second most affected cervical facet joint,

which is where the cervical facets transition to their posterolateral position.

Question 11

The medial branch

Answer 11

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

Question 12

The medial branch divisions

Answer 12

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.

Question 13

medial branch division of the medial branch innervates

Answer 13

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

Question 14

Each facet joint is innervated by

Answer 14

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)

Question 15

The position of the medial branch in the lumbar spine

Answer 15

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

Question 16

The mamilloaccessory ligament can

become calcified and be a source of

Answer 16

nerve entrapment, especially

at L5.

Question 17

The main variation in the lumbar spine is at L5

Answer 17

where it is the primary dorsal ramus itself that is

amenable to blockade

Question 18

in the thoracic spine the medial branches assume a courses

Answer 18

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

Question 19

How many cervical nerve roots?

Answer 19

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

Question 20

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

branches

Answer 20

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.

Question 21

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

Answer 21

dorsal ramus of C3.

Question 22

The C3 dorsal ramus divides into

Answer 22

two separate medial branches,

the larger of which is known as the third occipital nerve

Question 23

The C2 dorsal ramus divides into

Answer 23

up to five branches, the

largest of which is the greater occipital nerve.

Question 24

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

Answer 24

occipital headaches

Question 25

The facet joints contain

Answer 25

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

Question 26

facet arthropathy and facet-mediated pain pathopyisiology

Answer 26

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

Question 27

the greatest degree of motion and strain in the

Answer 27

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.

Question 28

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

Answer 28

(L4–5 and L5–S1)

Question 29

The most common presentation of trauma-induced facet pain is

Answer 29

whiplash injury

Question 30

The most reliable method to determine | facetogenic pain is with

Answer 30

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

Question 31

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

Answer 31

flank, hip and | upper lateral thigh

Question 32

For lower levels, pain is generally experienced in the

Answer 32

posterolateral thigh and occasionally | the calf.

Question 33

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

Answer 33

posterior upper neck and occipital region.

Question 34

Pathology involving middle cervical | facet joints tends to radiate into the

Answer 34

lower neck and supraclavicular region

Question 35

lower cervical facetogenic pain | typically causes pain in the

Answer 35

base of the neck and scapular region.

Question 36

limited utility in the diagnosis of | facet-mediated pain

Answer 36

radiologic examination

Question 37

diagnostic MBBs

Answer 37

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

Question 38

excessive volumes of local anesthetic solution

Answer 38

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

Question 39

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

Answer 39

false-positive results.

Question 40

Potential causes of false-positive blocks include

Answer 40

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

Question 41

the use of sedation for | diagnostic blocks should be limited

Answer 41

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

Question 42

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

Answer 42

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.

Question 43

One of the principal causes of false-negative blocks is

Answer 43

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 nerve(s).

Question 44

conservative management for spinal pain

Answer 44

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,

Question 45

The most commonly performed treatment for facetmediated | pain is

Answer 45

RF denervation

Question 46

The medial branch is denervated by

Answer 46

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

Question 47

The medial branch is denervated for the lumbar region

Answer 47

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

Question 48

The medial branch is denervated In | the cervical region

Answer 48

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

Question 49

Sensory stimulation

Answer 49

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

Question 50

Motor stimulation

Answer 50

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

Question 51

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

Answer 51

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

Question 52

The | duration of analgesia following RF denervation

Answer 52

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

Question 53

Surgery is occasionally done for facet pain

Answer 53

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

Question 54

COMPLICATIONS FROM MINIMALLY | INVASIVE INTERVENTIONS

Answer 54

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

Question 55

Postdenervation | neuritis can be reduced even further with

Answer 55

prophylactic | corticosteroid administration