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Anatomy, Nonoperative Results,
SECTION
22
Preoperative Injections, and Prescriptions
CHAPTER
e literature for spinal injections is rife with small studies of
limited quality. ere are multiple diculties with the research
on invasive pain therapies. First has been a lack of funding for
large-scale, high-quality, randomized controlled trials (RCTs).
is is partially due to the fact that there are no device or
pharmaceutical companies with a vested interest in funding
research on these therapies. Second, pain is, by denition, a
subjective experience. As with studies of therapies for psychological disorders, there is a signicant and growing placebo
eect in pain studies, which confounds the ability of studies
to show a signicant response over placebo.1 Alternatively, the
natural course for many patients with new-onset spinal pain
from disc herniation or other causes is to improve. Injection
therapies that do show improvement over time may, in part,
reect the natural healing process and overrepresent the
eects of these interventions. ird, there is substantial variability in the way that trials of some of these therapies have
been conducted. Some of the earlier trials of interlaminar and
caudal epidural steroid injections were done before uoroscopy and epidural contrast were routinely used. Comparing
these blind injections to the current standard of practice is
problematic. For many interventional pain procedures, the
bulk of the studies performed have been observational, retrospective, or otherwise of limited quality. Last, many studies
that purport to be placebo controlled have compared an active
treatment to something less than clearly a sham treatment. For
example, some studies have compared epidural steroids to
steroids given via another route. Other studies have compared
epidural injections to local anesthetic injections. ere is some
evidence that simply injecting saline or other solutions into
the epidural space has a therapeutic eect.2 us, the selection
of a reasonable sham for double-blind trials has been problematic and even RCTs with epidural saline as a control may
underestimate the eects of such interventions.
Anatomic Considerations in Spinal Pain
In order for a spinal structure to transmit painful impulses
into the central nervous system (CNS), the structure must be
innervated with nociceptors. ere are numerous structures
within the spine that are capable of transmitting pain when
Jerey L. Chen
Timothy J. Furnish
Mark S. Wallace
diseased. Oen, more than one structure can be diseased and
transmit pain, making it challenging to identify the pain
generator. Spinal injections can be useful, both diagnostically
and therapeutically, in the treatment of spine pain. However,
they should follow a careful history, physical examination, and
diagnostics tests. An understanding of the anatomy and
innervation of the spine is critical when utilizing spinal injections for diagnosis and treatment.
e innervation of the spine is complex, as both the sensory
and sympathetic nervous systems contribute to pain pathways.
e posterior aspect of vertebrae and discs as well as all
structures posterior to the vertebrae (i.e., neural foramen,
facets, and so on) are innervated segmentally from each spinal
root. However, since the sensory innervation of the anterior
and lateral portion of the vertebrae and discs travels via the
sympathetic nervous system, only the thoracic spinal nerves
and upper two lumbar spinal nerves transmit sensory bers
segmentally into the spinal cord. e anterior cervical spine
and lower anterior lumbar spine transmit sensory bers
through the rst 2 to 3 thoracic nerve roots and upper lumbar
nerve roots, respectively.
Zygapophyseal Joint (Facet Joint)
e facet joints are true diarthrodial joints with a rich nerve
supply transmitting both nociception and mechanoreception.3
e synovial membrane of the facet joints is rich in free nerve
endings associated with painful sensation.4 In addition, morphologic studies on human
the facet joint in low back pain. A recent study in degenerative
human facet joints and facet joint capsular tissue harvested at
the time of surgery showed an upregulation in inammatory
cytokines and neuropeptides (nerve growth factor) that can
sensitize and activate nociceptors.
e pain patterns that result from facet joint pathology
have been described by several investigators. Because these
joints are deep structures, there is a higher ratio of C ber to
A-delta ber innervation. is results in poorly localized pain
with a wide referral pain pattern from the ipsilateral lumbar
area to the ipsilateral posterior thigh. ese referral patterns
may result in secondary zones of reex muscle spasm and
resultant trigger points.
5–8
facet joints support the role of
9
III
383
384 SURGICAL ANATOMY AND APPROACHES
All facet joints are innervated segmentally by a medial
branch of the posterior ramus of the nerve root. However,
segmental innervation diers between the cervical, thoracic,
and lumbar spines. e cervical facet joint receives innervation from one level above and below, with the medial branch
located along the waist of the articular process above and
below the joint articulation. For example, the C3–C4 facet
joint is innervated by the C3 and C4 medial branches. e
C2–C3 facet joint receives innervation from the third occipital
nerve as it courses across the anterior lateral portion of this
joint as well as innervation from the C3 medial branch. e
thoracic facet joint medial branch travels superior to the tip
of the transverse process and courses proximally over the
pedicle to reach the joint capsule. Lumbar facets are supplied
by a medial branch at the corresponding level and a branch
from one level above. For example, the L4–L5 facet joint is
innervated by the L3 and L4 medial branch. e L5–S1 facet
joint is innervated by the L4 and L5 medial branches as well
as a branch from the posterior rami of S1.
Sacroiliac Joint
As with the facet joint, there has been controversy on the
sacroiliac (SI) joint as a cause of low back pain. Like the facet
joints, the SI joint is richly innervated with both free nerve
endings and mechanoreceptors. e innervation has been
extensively described and supports this joint as a pain-sensitive
structure.
10,11
Most of the innervation of the SI joint is supplied
dorsally from L4–S4 nerve roots, which results in the bulk of
the innervation occurring in the dorsal segment of the joint.
12
Pain from the SI joint is usually referred to the buttocks,
groin, posterior thigh, and occasionally, below the knee.
13–15
Because of the anatomic location of the SI joint, this structure
is dicult to examine, and many of the provocative tests can
result in false-positives and intertester dierences.
16,17
Intervertebral Disc
It is clear that the outer one-third of the intervertebral disc
(ID) is well innervated; however, there is controversy regarding whether this is a pain-producing structure.
little, if any, controversy over the role that a herniated disc
plays in producing radicular pain; however, controversy arises
over isolated disc pathology without nerve compression as a
cause of axial low back pain. Nerve endings capable of transmitting pain impulses are abundant in the outer one-third of
the anulus brosus in both the cervical disc21 and the lumbar
disc.22 In addition, nerves within the ID contain neuropeptides
that are involved in pain transmission.23 Injuries in the anulus
brosus may result in pain while the external appearance of
the disc remains normal and before nerve roots are aected.
e referral pattern of pain originating solely from the disc
is similar to that produced by facet joint pain.25 e pain from
diseased intervertebral discs may not arise directly from the
disc, but rather from other structures that develop abnormal
stresses as a result of the diseased disc.26 Other structures
surrounding the disc are known to have pain bers (e.g., facet
joints, anterior and posterior longitudinal ligaments).
18–20
ere is
24
Ligaments of the Spine
ere are many ligamentous structures in the spine that are
innervated with free nerve endings. However, there is variability in the density of this innervation. Of all of the ligamentous structures, the posterior longitudinal ligament appears to
be the most heavily innervated with free nerve endings
the ligamentum avum the least innervated.29 Degenerative
changes within these ligaments may result in sensitization of
free nerve endings, leading to chronic pain. In addition, the
close proximity of the anterior and posterior longitudinal ligament to the discs makes the structures susceptible to exposure
to the disc contents in the event of disc rupture. e disc
contents may induce an inammatory process in these ligaments, leading to pain.
Nerve Root
e nerve root is innervated by the sinuvertebral nerve, which
branches from the segmental nerve and travels backward into
the neural foramen. e arachnoidal covering of the nerve
root is heavily innervated and a source of pain. Mechanical
compression or irritation of these structures can lead to pain
in the extremities that is associated with neurologic changes.
e nerve root may be stimulated mechanically by disc herniation, osteophyte formation, foraminal narrowing due to
degenerative disc disease, or tumor invasion. In addition, it
has been postulated that both the disc contents and the facet
joint contents may induce an arachnoiditis; however, Haughton et al.30 showed this only to be true for the disc contents.
Cervical Spine Injections
Cervical epidural steroid injections have been performed from
both an interlaminar and transforaminal approach. All epidural injections carry a small risk of complications. However,
the cervical transforaminal approach, more than other spinal
locations or approaches, has been associated with rare but
signicant complications, including spinal cord injury, stroke,
and death.
utilized the interlaminar approach. In two recent reviews of
cervical epidural steroid injections, seven RCTs for the treatment of axial or radicular pain of cervical spinal origin were
evaluated.
using uoroscopy. Of the studies for cervical radicular pain,
only one study made use of uoroscopic guidance. All of the
studies showed signicant pain improvement but no dierences between epidural steroid treatment and active-control
groups, with the exception of one study, which used an
intramuscular injection of steroid as the control group. e
remaining studies compared epidural steroids versus other
substances (mostly local anesthetics) injected epidurally.
chronic pain conditions is increasingly focused on multimodal therapies. Patients who undergo treatment with
multiple modalities or combinations of pharmaceutical and
31–33
e majority of studies of cervical epidural injections have
34,35
Only three of the seven studies were performed
e literature regarding the treatment of acute and
27,28
and
Chapter 22 Anatomy, Nonoperative Results, Preoperative Injections, and Prescriptions 385
SECTION
III
A
FIG. 22.1 Cervical epidural steroid injection. (A) Contralateral oblique view showing contrast medium in the
cervical epidural space. (B) Anteroposterior view showing contrast medium highlighting epidural fat with
needle entry at the right C7–T1 level.
nonpharmaceutical treatments fare better than those receiving a single-modality treatment. A recent multicenter RCT
of cervical epidural steroid injections (CESIs) for the treatment of cervical radiculopathy showed greater benets for
multimodal therapy over more limited therapy.36 A total of 169
subjects were randomized to physical therapy plus gabapentin,
cervical epidural steroid injections alone, or a combination
of physical therapy, gabapentin, and CESIs. All three groups
showed signicant improvement in arm pain at follow-up.
However, the magnitude of improvement was signicantly
greater for the multimodal group than the physical therapy or
epidural-alone groups. e conservative therapy group fared
the worst.
Procedure: Cervical Interlaminar Epidural Steroid Injection
e patient is placed in a prone position. e patient is prepped
and draped in the usual sterile fashion. A uoroscopic image
is taken in the anteroposterior (AP) direction and a 5- to
10-degree cephalad tilt of the C-arm may be required to open
the C7–T1 space. e C7–T1 level is selected because the
epidural space is widest and there is a higher chance of an
intact ligament, both making a safer injection. e C6–C7
space may be occasionally used, but it is not recommended
that the injection be performed above C6 as the cervical
enlargement of the spinal cord, thin ligament, and small epidural space increase risk of injury. A pointer is then placed
over the superior edge of the lamina of the inferior vertebral
level of the target, at the ipsilateral side of the pain complaint
for a paramedian approach. (An alternative method is the
trajectory view, to follow.) A skin wheal is performed and the
area is anesthetized with lidocaine 1%. A Tuohy needle is then
inserted coaxial to the radiographic beam and advanced until
contacting the lamina. e needle is then walked o the
lamina superiorly and advanced into the ligamentum avum.
e stylet is removed, and a loss of resistance (LOR) syringe
is then placed on the hub of the needle. At this stage, a contralateral oblique 50-degree C-arm view is recommended to
B
watch needle depth. Continuous light pressure is applied with
one hand to the LOR syringe, and the needle is advanced with
the other hand. Once LOR is obtained, the LOR syringe is
removed. In the contralateral oblique view, the needle tip
should be advanced just ventral to the spinolaminar line.
When using a paramedian approach, a lateral view is not
appropriate, as it will not give an adequate view of needle
depth just below the ipsilateral lamina. Iohexol (Omnipaque
240) is injected slowly to conrm proper spread of the contrast
medium within the epidural space, also conrming that there
is no evidence of intrathecal spread or intravascular runo.
About 3 mL of injectate mix of steroid, and normal saline with
or without anesthetic is then performed.
37–39
An alternative
method is the trajectory view, in which the needle trajectory
is directed toward the interlaminar space without any intent
of contacting lamina; a 50-degree contralateral oblique C-arm
view is required to watch needle depth, prior to advancing the
needle into the epidural space38 (Fig. 22.1).
Transforaminal epidural steroid injections (TFESIs) and
selective nerve root blocks have been promoted as a more
targeted modality for treatment or diagnostic purposes.
However, there are no randomized, double-blind trials of
cervical transforaminal ESIs or comparative studies between
transforaminal and interlaminar ESIs. In a review of uoroscopically guided transforaminal CESIs, Engel et al.40 reported
on six observational studies totaling 357 patients who underwent uoroscopically guided cervical TFESIs for radicular
pain. Of these subjects, 180 (50%) obtained at least a 50%
reduction of arm pain. Of the six studies, four had a positive
outcome—at least 50% of subjects achieving signicant
improvement. One of these studies was halted early due to
published reports of complications with cervical TFESI.41 Two
of the six studies of cervical TFESIs also reported on progression to surgery. In a study of 70 subjects by Lin in 2006, 44 of
the 70 subjects had signicant and sustained improvement
such that they did not proceed to surgery.42 However, in a
study of 21 subjects with cervical radiculopathy by Kolstad in
2005, only 5 of the 21 had improvement sucient to prevent
progression to surgery.
41
386 SURGICAL ANATOMY AND APPROACHES
ere have been at least 23 reports of serious complications
aer cervical TFESI.36 ese have included cerebral injuries
with cortical blindness, spinal cord infarcts, vertebral artery
occlusion, cerebral and cerebellar infarcts, spinal cord injury,
grand mal seizure, and epidural hematomas, among others.
ere are also reports of adverse events following cervical
interlaminar ESIs, but many of these are minor and transient.32
ere have been a small number of direct spinal cord injuries,
but in all of these cases, the injections were performed in
heavily sedated patients.32 e use of heavy sedation for spinal
injection procedures, especially in the cervical region, is discouraged for this reason.43 ere is growing consensus that
transforaminal injections in the cervical region pose a signicantly higher risk than interlaminar epidurals and perhaps
should be avoided.
2,44
Cervical selective nerve root blocks have been promoted
as a diagnostic test to aid in planning surgical treatment of
cervical radiculopathy. However, scant evidence exists for the
diagnostic utility of cervical selective nerve root blocks. In a
review of the literature on selective nerve root blocks, only
one study was found that evaluated cervical injections.45 In
this study, 30 patients with unilateral cervical radiculopathy
and more than one level of pathology on magnetic resonance
imaging (MRI) underwent diagnostic selective nerve blocks.46
Correlation between positive selective nerve block and clinical
determination of nerve root level from neurologic decits was
only 28%. Correlation with the most severe pathology on MRI
was 60%. Given the limited evidence and potential risks, there
is little to support the use of cervical diagnostic nerve root
blocks for surgical planning.
A
Procedure: Cervical Transforaminal Epidural Steroid Injection
e patient is placed in a supine position. e appropriate
vertebral level is identied under the posteroanterior (PA)
view, and the C-arm is tilted until the superior endplate is
squared, and the spinous process is midline to the level that is
targeted. e uoroscope is then tilted ipsilaterally to about
45 degrees or until the targeted foramen comes into complete
view. A pointer is then placed over the intervertebral foramen
at the dorsal and posterior aspect. e skin is anesthetized. A
straight short-bevel needle is then advanced toward the target.
A PA view is then obtained, and the needle can be advanced,
but not past the midline of the lateral mass in order to minimize the potential for dural or spinal cord puncture. Iohexol
(Omnipaque 240) is then injected under live uoroscopy to
conrm contrast spread medially around the pedicle, and
inferiolaterally along the exiting spinal nerve, without vascular
runo. It has been suggested that use of digital subtraction
angiography (DSA) has a greater accuracy in detecting intravascular injection. Lee et al.47 showed that, of 87 lumbar
TFESIs, 20 cases of intravascular injection were detected with
DSA. Only 12 of these cases were detected with contrast injection under standard uoroscopy. In a study of 177 cervical
TFESIs in 134 patients, Mclean et al.48 detected intravascular
injection in 18% with real-time uoroscopy versus 32.8% with
DSA. About 1 to 2 mL of injectate mix of dexamethasone and
B
FIG. 22.2 Cervical transforaminal epidural steroid injection. (A) Oblique
view of a C6–C7 intervertebral foramen aligned with the needle coaxial to
the target point. (B) Posteroanterior view showing the contrast medium
lling the foramen, extending peripherally along the ventral ramus, and to
the epidural space.
normal saline with or without anesthetic is then performed.
49,50
All other steroids should be avoided due to the risk of neurologic damage. In a rat study of four dierent steroid preparations (both soluble and nonsoluble), dexamethasone was the
only one that did not result in serious neurologic injury aer
carotid artery injection.51 e general consensus is that DSA
is not required when using dexamethasone. However, DSA
should be strongly considered if a particulate steroid is used
under special circumstances (Fig. 22.2).
Pain from the cervical facet joints has been reported to
account for between 36% and 67% of patients with chronic
neck pain.
52,53
Cervical facet–mediated pain is routinely
treated with ablation of the medial branch nerves. Unlike in
the lumbar region, there is limited literature on the use of
intraarticular steroid injections into the cervical facet joints.
Only one randomized trial exists that compared intraarticular
Chapter 22 Anatomy, Nonoperative Results, Preoperative Injections, and Prescriptions 387
injection of steroid to local anesthetic.54 Both groups obtained
relief lasting only days, with no dierence between groups.
Two observational studies of cervical facet intraarticular
steroid injections showed short-term benet.
55,56
ere is one high-quality RCT of cervical medial branch
radiofrequency ablation (RFA) aer controlled diagnostic
blocks.57 In this small study by Lord, 24 patients were randomized to sham or RFA. e median time to return of pain was
284 days in the treatment group and 8 days in the sham group.
Nonrandomized prospective studies have also found both
short-term and long-term benet from cervical RFA of the
medial branch nerves, while two larger retrospective studies
found no benet.
52,53
Procedure: Cervical Medial Branch Blocks and Radiofrequency Ablation
Cervical medial branch blocks (MBB) are typically performed
as a diagnostic technique to determine whether the patient’s
neck pain is secondary to a facet joint pathology and to
determine if the patient is a candidate for RFA. Prior to considering MBB and RFA the pain should have been present for
at least 3 months, and the patient needs to have not responded
to conservative therapy. e goal of the procedure is to inject
anesthetic at the paravertebral facet joint nerves or the medial
branches.
Each facet joint is supplied by two medial branches of the
dorsal rami. In the cervical spine, two levels must be anesthetized for each joint. For example, the C3 and C4 MBB is
performed to obtain information about the C3–C4 facet joint,
and the C4 and C5 MBB is performed to obtain information
regarding the C4–C5 facet joint.
For the diagnostic cervical MBB, the patient is usually
placed in a prone position. e patient is prepped and draped
in the usual sterile fashion. e skin and so tissues are
anesthetized with lidocaine 1%. At each level from a lateral
direction, a 1.25- to 1.5-inch needle—or from a posterior
position, a spinal needle—is inserted under frontal, lateral,
and oblique uoroscopic projections with the needle tip
advanced to contact the centroid of the lateral articular pillar
at each respective level. Aspiration of each needle must be
negative for blood, cerebrospinal uid, or paresthesia prior to
injection. e nerve blocks are then performed by injecting
bupivacaine 0.5%, 0.25 mL through each needle.
If the patient exhibits greater than 50% improvement of
index pain with 0.25 mL of local anesthetic for at least 3 hours,
this is considered a positive diagnostic block. e patient may
then proceed to a therapeutic procedure, such as RFA.
RFA is performed with the same set-up and targets as the
MBB, except the needle tip should be placed parallel to the
nerve. e RF lesion is an oval-shaped lesion that is circumferentially around the sha of the active tip; thus, an ideal
position of the tip is parallel to the targeted nerve.
58
From a posterior approach at each level, a 22-gauge,
100-mm RF cannula needle with a 10-mm active tip is inserted
percutaneously to the radiographic target with the needle tip
parallel to the periosteum of the lateral articular pillar. Alternatively, from a lateral approach, a 20-gauge, 50-mm RF
cannula needle with a 5-mm active tip is inserted percutaneously to the radiographic target at the center of the lateral
mass. e RF probes are then placed through the cannula.
Needle placement is conrmed radiographically and with
neurologic stimulation. Axial sensory perception threshold
using 50-Hz sensory stimulation is achieved at 0.5 V or less at
each level. Extremity motor stimulation at 2 Hz is negative at
a minimum of 1.5 V, or 2 to 3 times the sensory threshold at
each level. Motor stimulation is positive for multidus stimulation. e paravertebral facet joint nerve blockade is performed by injection of lidocaine 2%, 0.5 mL per level prior to
treatment. Each nerve is then treated at 80°C in continuous
RF mode for 90 seconds. e needle can be rotated and treated
57,59,60
again.
Next, paravertebral facet joint nerve blockade is
performed by injection of bupivacaine 0.5%, 0.25 mL. If
steroid is mixed with the bupivacaine, it is recommended that
dexamethasone be used for reasons described earlier under
the risk of intraarterial injection of particulate steroid. e
deep cervical artery is at risk of penetration and can communicate with the spinal radicular arteries (Fig. 22.3).
SECTION
III
BA
FIG. 22.3 Cervical medial branch block/radiofrequency (RF) ablation. (A) Anteroposterior view showing RF
needles placed at the left spine lateral to the articular pillars. (B) Lateral view with the electrodes in the proper
position over the left cervical third occipital, third, fourth, and fth articular pillars.
388 SURGICAL ANATOMY AND APPROACHES
Lumbar Spine Injections
Lumbar epidural steroid injections have been used for years
as a treatment for axial or radicular pain of spinal origin.
Lumbar ESIs are oen used as an intermediate or conservative
treatment measure before considering surgery. In a metaanalysis, Bicket et al. evaluated the eect of lumbar epidural
steroid injections for preventing surgery for lumbar radiculop at hy.61 ey identied 22 studies of lumbar ESIs that were
RCTs and also reported subject progression to surgery. ey
found that fewer patients in the groups who had received ESIs
went on to have surgery in both the short term and long term,
but the eect fell short of statistical signicance. However,
only one of the included studies specically sought to determine the eect of ESIs on surgery as a primary outcome
measure. is study by Riew et al. found that signicantly
fewer patients who received ESIs (8 out of 28 [28.6%]) compared to epidural bupivacaine alone (18 out of 27 [66.7%])
underwent surgery at 13 to 28 months of follow-up.
erapeutic epidural steroid injections have been used
for the treatment of pain from spinal stenosis, discogenic
pain, and lumbar radiculopathy. Radiculopathy from lumbar
disc herniation remains the primary indication for ESIs.
In a review of uoroscopically guided lumbar interlaminar
ESIs, 5 out of 8 randomized controlled trials showed positive
short-term pain relief.63 In a separate review of 4 randomized
trials of transforaminal ESIs for lumbar radiculopathy, all
showed positive short-term improvement and 2 of 4 showed
longer-term improvement.64 In his study of 160 patients
with unilateral radiculopathy, Karppinen found that, for
contained herniations, a transforaminal ESI prevented progression to surgery but provided no relief in herniations with
extrusion.
65
Axial low back and leg pain from lumbar spinal stenosis
has also been treated with epidural steroid injections. e use
of epidural steroid injections for lumbar stenosis has recently
been mired in some controversy. While lumbar decompression is considered the gold standard therapy for lumbar spinal
stenosis, not all patients are acceptable surgical candidates. In
an RCT that received wide reporting in the lay press, Friedly
et al.66 reported no dierence for epidural steroid injections
when compared to epidural lidocaine injections at 6 weeks
and concluded that ESIs were ineective for lumbar spinal
stenosis. However, this study has been criticized for using relatively low volumes of injectate, inclusion of patients with acute
low back pain, and the injection of an active drug, lidocaine, as
an inactive control.67 While the steroid group had signicant
improvement compared to lidocaine at 3 weeks for both of
the primary outcome measures, Roland-Morris Disability
Questionnaire (RMDQ) score and leg pain, there was no
statistical dierence at 6 weeks. However, both the lidocaine
and steroid groups had substantial percentages (nearly 50%)
of subjects achieving more than 30% relief of leg pain compared to baseline and 38% in both groups reported more than
50% relief of leg pain. In a meta-analysis of epidural steroid
injections compared to epidural injections of nonsteroid
solutions and injections of solutions outside of the epidural
62
space, Bicket et al.2 concluded that epidural injections of any
solution appear to confer therapeutic benet and the use of
epidural nonsteroid solution injections as a “placebo” control
may be misleading. In a systematic review of RCTs of ESIs for
lumbar stenosis, Manchikanti68 concluded that interlaminar
and caudal injections of either local anesthetic with steroid or
local anesthetic alone provided short- and long-term benet
for back and leg pain.
Procedure: Lumbar Interlaminar Epidural Steroid Injection
For this procedure, the patient is placed in a prone position.
e patient is prepped and draped in the usual sterile fashion.
A uoroscopic image is taken in the AP direction and the
endplates at the level of planned entry are lined up, most
commonly at L5–S1. A pointer is then placed over the superior
edge of the lamina of the inferior vertebral level of the target,
at the ipsilateral side of the pain for a paramedian approach.
(As with a cervical epidural steroid injection, an alternative
method for the lumbar epidural steroid injection is the trajectory view, in which the needle trajectory is directly toward the
interlaminar space; a 45-degree contralateral oblique C-arm
view is required to watch needle depth if the lamina is not
going to be contacted prior to advancing the needle into
the epidural space). A skin wheal is performed and the area
is anesthetized with lidocaine 1%. A Tuohy needle is then
inserted coaxial to the radiographic beam and advanced until
contacting the lamina. e needle is then walked o the lamina
superiorly and advanced anteriorly to the ligamentum avum.
e stylet is removed, and a LOR syringe is then placed on the
hub of the needle. Continuous light pressure is applied with
one hand to the LOR syringe, and the needle is advanced. At
this stage, a contralateral oblique 50-degree C-arm view is
recommended to watch needle depth. Once LOR is obtained,
the LOR syringe is removed. In the contralateral oblique
view, the needle tip should be advanced just ventral to the
spinolaminar line. Iohexol (Omnipaque 240) is injected slowly
to conrm proper spread of the contrast medium within the
epidural space, also conrming that there is no evidence
of intrathecal spread or intravascular runo. When using a
paramedian approach, a lateral view is not appropriate, as it
will not give an adequate view of needle depth just below the
ipsilateral lamina. If using a midline approach, a lateral view is
appropriate to monitor needle depth. About 5 mL of injectate
mix of steroid and normal saline with or without anesthetic
is then performed
38,69,70
(Fig. 22.4).
Procedure: Caudal Epidural Steroid Injection
e patient is placed in a prone position with a pillow under
the abdomen, and the legs slightly abducted with internal
rotation. e patient is prepped and draped in the usual sterile
fashion. e sacral cornu may be palpated to determine the
approximation of the sacral hiatus. A pointer is placed over
the sacral hiatus at around a 45-degree angle using a lateral
uoroscopic projection to assist in identifying the sacral
hiatus. e skin is then anesthetized with lidocaine 1%, and
Chapter 22 Anatomy, Nonoperative Results, Preoperative Injections, and Prescriptions 389
BA
FIG. 22.4 Lumbar epidural steroid injection. (A) Contralateral oblique view showing contrast medium in the
lumbar epidural space. (B) Anteroposterior view showing contrast medium highlighting epidural fat with the
needle at right L5–S1 level.
SECTION
III
A
FIG. 22.5 Caudal epidural steroid injection. (A) Lateral view showing a 25-gauge needle in the caudal epidural
space with contrast medium owing superiorly in the epidural space. (B) Anteroposterior view showing
contrast medium highlighting caudal epidural fat.
a 27-gauge, 1.25-inch needle, or longer needle if needed, is
inserted into position through the sacral hiatus. e needle is
advanced midline, and kept inferior to S3 to avoid dural
puncture. Aer negative needle aspiration, contrast is then
injected to demonstrate epidural spread in both a lateral and
AP projection. Live AP uoroscopic imaging is then obtained
highlighting epidural fat, and cephalad contrast spread without
vascular runo. e usual volume of 5 to 10 mL of injectate
mix of steroid and normal saline with or without anesthetic is
then performed
71–73
(Fig. 22.5).
e use of diagnostic selective nerve root blocks to identify
a particular spinal nerve level in the lumbar region has signicantly more evidence than in the cervical region. In his review
of these blocks, Datta45 found moderate evidence for the ecacy of selective nerve blocks as a diagnostic tool in radicular
pain. However, there are signicant variables that may confound the results of these injections. First, there may be confusion between the interventional pain physician and spine
B
surgeon regarding what type of block is being performed and
for what purpose. Some physicians will use the terms transfo-
raminal and selective nerve block interchangeably. e goal of
a truly selective nerve block is to place the needle tip just
outside of the foramen and inject a low volume of local anesthetic alone in order to block a single nerve root. Improper
placement of the needle tip into the foramen, injection of
steroid along with local anesthetic, or use of a larger volume
of injectate may negate the diagnostic utility of the injection.
In one study, 0.5 mL of local anesthetic and iohexol resulted
in epidural spread in 47% of L4 blocks and 28% of L5 blocks.74
e sensitivity and specicity of nerve root blocks for predicting surgical outcome ranges from 45% to 100% in the various
studies. ere may be a role for the use of selective nerve
blocks when there is clinical evidence of radiculopathy but
inconclusive imaging studies. However, surgeons should
consider the subjective nature of these blocks as a diagnostic
test when evaluating their results.
390 SURGICAL ANATOMY AND APPROACHES
Procedure: Lumbar Transforaminal Epidural Steroid Injection
ere are dierent approaches for this procedure, including
the supraneural (subpedicular) approach and infraneural
(retrodiscal) approach. e supraneural approach is the traditional method and most commonly used among pain practitioners, and is described here. All of the risks and precautions
described for cervical TFESIs should be considered for lumbar
TFESIs.
e patient is placed in a prone position. e appropriate
vertebral level is identied, and the uoroscope is angled
cephalocaudad until the superior endplate is squared, and
mediolaterally until the spinous process is midline between
the pedicles. e C-arm is then tilted ipsilaterally to between
15 and 25 degrees, until the superior articular process projects
over the lateral third of the vertebral body. A pointer is then
placed under the 6 o'clock position of the pedicle, adjacent to
the pars interarticularis. A spinal needle is then advanced
coaxial to the uoroscopic image to the target. A lateral uoroscopic view is then obtained, and the needle is advanced to
the cephalad third of the intervertebral foramen and midway
anteriorly into the neural foramen, to potentially avoid vascular structures. At this point, the C-arm is moved to an AP
position and the needle position is conrmed to have not
passed the midpedicular line to minimize the potential of
dural puncture. Iohexol (Omnipaque 240) is then injected
under live uoroscopy. Ideal epidural contrast spread should
be medially and cephalad around the pedicle, and inferior
along the exiting spinal nerve, without vascular runo or
intrathecal spread. About 1 to 2 mL of an injectate mix of
dexamethasone and normal saline with or without preservativefree local anesthetic is then performed.
e lumbar TFESI can be performed at the L5–S1 and S1
levels with slight variation. At L5–S1, the iliac crest may
75,76
obscure the view, and the C-arm may require a larger degree
of cephalocaudal tilt.77 For S1, the C-arm is adjusted to optimize visualization of the dorsal S1 foramen, just inferior to the
S1 pedicle, with the target more medial within the foramen.
e lateral view is used to conrm needle depth.
78
e technique for a selective nerve root block is similar to
what is described earlier for the TFESI, however, with nal
needle position more lateral and inferior. As the goal for a
selective nerve root block is an anesthetic block to the exiting
spinal nerve, ideal contrast spread is inferior along the exiting
spinal nerve, without medial epidural spread. To be selective,
a nerve root block should be performed extraforaminally,
distal to the division of the ventral and dorsal rami and with
low volumes of local anesthetic—no more than 0.5 mL79
(Fig. 22.6).
In the lumbar region, the facet joints have been implicated
as a source of axial low back pain in 15% to 45% of patients.52
Diagnostic physical examination maneuvers and radiographic
studies are unreliable in diagnosing facet-mediated pain. e
use of controlled diagnostic medial branch nerve blocks is
considered the most reliable means of diagnosing pain arising
from the facet joints. Additionally, a positive response to two
comparative local anesthetic diagnostic blocks signicantly
increases the likelihood of a robust response to radiofrequency
ablation treatments compared to a single diagnostic block.52
In their review of RFA for lumbar facet pain, Manchekanti
et al. evaluated four randomized, sham controlled trials of
RFA for lumbar facet mediated pain.80 ree showed positive
results for both short-term (<6 months) and long-term (>6
months) pain relief. Additionally, they found three other
randomized, active controlled trials and 10 observational
studies with positive results. In one representative study by
van Kleef, success was dened as a more than 2-point reduction in visual analogue pain scale and more than 50% reduction in Oswestry Disability Index.81 Patients were assessed at
A
FIG. 22.6 Lumbar transforaminal epidural steroid injection. (A) Oblique radiograph of the spinal needle placed
below the L5 pedicle. (B) Lateral radiograph showing the spinal needle in the upper third of the L5–S1 neural
foramen. (C) Anteroposterior radiograph showing contrast medium highlighting the exiting nerve root.
B
C
Chapter 22 Anatomy, Nonoperative Results, Preoperative Injections, and Prescriptions 391
2, 3, 6, and 12 months; the treatment group had signicantly
greater improvement at all time points.
ere have been a handful of observational and retrospective studies of intraarticular injection of local anesthetic and
steroids.82 Most of the studies found greater than 50% of
patients obtained initial and immediate relief and some shortterm but not long-term benet. ere is no well-done, randomized, placebo-controlled trial of intraarticular facet
injections.
Procedure: Lumbar Zygapophyseal Joint Injections (Facet Joint)
e patient is placed in a prone position. e patient is
prepped and draped in the usual sterile fashion. e C-arm is
positioned in the AP direction, and is given a 5- to 15-degree
ipsilateral tilt until the facet joint space is identied clearly.
e target is the middle to upper half of the joint space at
the medial or lateral side of the joint. Osteophytic formation may aect the superior articular process more than the
inferior articular process, making the lateral portion of the
joint more dicult to enter. e medial border of the joint
may be better suited in these cases. Special attention is paid to
the L5–S1 facet joint, as the iliac crest can be superimposed,
and may require more cephalad tilt. e skin is then anesthetized, and a spinal needle is then inserted and advanced
coaxial to the radiographic beam until it enters the joint. At
this point, more than one oblique angle, or lateral image, can
be checked to conrm the needle tip within the joint space.
Injection of iohexol (Omnipaque 240) shows joint space
and capsular spread. Due to the small volume of the facet
joint, a volume of no more than 1 to 1.5 mL per level of
injectate mix of steroid and anesthetic is then performed
(Fig. 22.7).
83–85
Procedure: Lumbar Medial Branch Blocks and Radiofrequency Ablation
Lumbar MBBs are typically performed for two reasons. e
rst is to obtain diagnostic information as to whether the
patient’s axial back pain is secondary to facet-mediated pain
from lumbar spondylosis. e second reason is to determine
if the patient is a candidate for RFA. Prior to considering
MBB and RFA, the pain should have been present for at least
3 months, and the patient needs to have not responded to
conservative therapy. e goal of the procedure is to inject
anesthetic at the paravertebral facet joint nerves or the medial
branches.
Each facet joint is supplied by two medial branches of the
dorsal rami. In the lumbar spine, two levels must be anesthetized for each joint. At the lowest joint, L5–S1, the L4 medial
branch and the L5 dorsal ramus must be blocked. As the most
common severe lumbar spondylosis occurs at the L4–L5 and
L5–S1 joints, the most common MBB procedures are performed at the L3, L4, and L5 medial branches.
For the diagnostic lumbar MBB, the patient is placed in a
prone position. e patient is prepped and draped in the usual
sterile fashion. A uoroscopic image is taken in the AP direction and the endplates at the level of proposed entry are lined
up. Next, the uoroscope is rotated ipsilaterally 10 to 20
degrees until the junction of the superior articular process and
transverse process is clearly visible, with the circular projection of the pedicle outlining this junction. e skin and so
tissues are anesthetized with lidocaine 1% at each site.
To block the lumbar medial branch nerves, a spinal needle
is inserted percutaneously and advanced under uoroscopic
guidance using dorsal, lateral, and oblique projections to its
radiographic target. For each of the lumbar levels, the tip of
the needle should be placed at the junction of the superior
articular process and the transverse process. e L5 posterior
SECTION
III
A
FIG. 22.7 Lumbar facet joint injection. (A) Oblique radiograph with the tip of the spinal needle placed in the
right L4–L5 facet joint. (B) Oblique radiograph with contrast spread at the right L4–L5 facet joint.
B
392 SURGICAL ANATOMY AND APPROACHES
A
FIG. 22.8 Lumbar medial branch block/radiofrequency ablation. (A) Anteroposterior radiograph showing
needles placed at the target of the left L3, L4, and L5 medial branches. (B) Lateral radiograph showing
appropriate placement of the needles.
rami are blocked at the junction of the sacral ala just lateral to
the articular process. At the sacral levels, the needle is placed
at the lateral border of the respective sacral foramen. Next,
paravertebral facet joint nerve blockade is performed by injection of bupivacaine 0.5% or lidocaine 2%, 0.5 mL of anesthetic
at each level.
A patient exhibiting greater than 50% improvement of axial
low back pain with 0.5 mL of local anesthetic for at least 3
hours may be a candidate for RFA. e purpose of RFA of the
paravertebral facet joint nerves is to provide prolonged symptomatic pain relief.
For lumbar RFA, the patient is once again placed in the
prone position, and prepped and draped in the usual sterile
fashion. A uoroscopic image is taken in the AP direction
and the endplates at the level of proposed entry are lined up.
e skin and so tissues are anesthetized with lidocaine 1%
at each site.
A 20- or 22-gauge, 10-cm RFA needle is inserted percutaneously and advanced under uoroscopic guidance using
dorsal, lateral, and oblique projections to its radiographic
target, as described earlier in the MBB section. e dierence
in technique is that the needle tip should be placed parallel
to the nerve. As described in the cervical section, the RF
causes an oval circumferential shaped lesion around the sha
of the active tip; thus, an ideal position of the tip is parallel to
the targeted nerve.58 e RF probes are then placed through
the cannula. In addition to uoroscopic conrmation, neurologic stimulation is undertaken with both motor and sensory
testing. Axial sensory perception threshold using 50-Hz
sensory stimulation is achieved at 0.5 V or less at each level.
Extremity motor stimulation at 2 Hz is shown to be negative
at a minimum of 1.5 V, or 2 to 3 times the sensory threshold
at each level, and motor stimulation is positive for multidus
stimulation, without movement of the buttock or leg muscles.
Paravertebral facet joint nerve blockade is performed by
B
injection of lidocaine 2%, 0.5 mL per level before treatment.
Aer nerve block is achieved, each nerve is then treated at
80°C in continuous RF mode, for 90 seconds. e needle can
be rotated and treated again.
86–90
Finally, paravertebral facet
joint nerve blockade is performed by injection of bupivacaine
0.5%, 0.5 mL at each level (Fig. 22.8).
e SI joint has long been an acknowledged source of low
back pain. Diagnosis of the SI joint as the source of pain
remains a challenge as the diagnostic examination maneuvers
for SI joint pain lack specicity. Based on a combination of
multiple examination maneuvers and diagnostic nerve blocks,
the prevalence of SI joint dysfunction in unilateral low back
pain has been estimated at 15% to 25%.91 ere are many
physical examination tests that have been advocated for diagnosing SI joint pain. Two of the most common are the Patrick’s
(FABERS) test and Gaenslen’s test. Two studies have shown an
improvement in specicity to 79% and 85% when three or
more examination tests are positive.
92,93
Imaging study nd-
ings are poorly correlated with injection-conrmed SI joint
91,94
pain.
e International Association for the Study of Pain
(IASP) criteria for diagnosing SI joint pain mandates that the
pain should be alleviated by the intraarticular injection of
local anesthetics.95 However, even this diagnostic technique
has its limits. Intraarticular injection of the SI joint is one of
the most challenging spinal injection procedures. ere are
several factors that may confound the diagnostic utility of an
SI joint injection. e SI joint space is small; thus, local anesthetics injected may extravasate and block other anatomic
structures such as muscles, ligaments, or lumbosacral nerve
roots, resulting in false positives. Failure to get local anesthetic
spread within the joint may result in a false negative.
91,94
All
of these factors require consideration while attempting to
diagnose pain from the SI joint.
Nonsurgical SI joint pain procedural interventions are
limited to the injection of steroids and local anesthetics or