**Covered Indications Facet Joint Interventions:**

Facet joint interventions generally consist of 4 types of procedures: intra-
articular (IA) facet joint injections, medial branch blocks (MBB), and
radiofrequency ablations (RFA) and facet cyst rupture/aspiration.

Facet joint interventions are considered medically reasonable and necessary
for the diagnosis and treatment of chronic pain in patients who meet **ALL**
the following criteria:

  1. Moderate-to-severe chronic neck or low back pain, predominantly axial, that causes functional deficit measured on pain or disability scale*
  2. Pain present for minimum of 3 months with documented failure to respond to non-invasive conservative management (as tolerated) 
  3. Absence of untreated radiculopathy or neurogenic claudication (except for radiculopathy caused by facet joint synovial cyst)
  4. There is no non-facet pathology per clinical assessment or radiology studies that could explain the source of the patient's pain, including but not limited to fracture, tumor, infection, or significant deformity

*Pain assessment must be performed at baseline, after each diagnostic procedure using the **same** pain or disability scale for each assessment. A disability scale must also be obtained at baseline to be used for functional assessment (if patient qualifies for treatment). 

  1. **Diagnostic Facet Joint Procedures (IA or MBB):**

The primary indication of a diagnostic facet joint procedure is to diagnose
whether the patient has facet syndrome. IA facet block(s) are considered
reasonable and necessary as a diagnostic test only if MBBs cannot be performed
due to specific documented anatomic restrictions or there is an indication to
proceed with therapeutic IA injections. These restrictions must be clearly
documented in the medical record and made available upon request.

Diagnostic procedures should be performed with the intent that if successful,
RFA procedure would be considered the primary treatment goal at the diagnosed
level(s).

A second diagnostic facet procedure is considered medically necessary to
confirm validity of the initial diagnostic facet procedure when administered
at the same level. The second diagnostic procedure may only be performed a
minimum of 2 weeks after the initial diagnostic procedure. Clinical
circumstances that necessitate an exception to the 2-week duration may be
considered on an individual basis and must be clearly documented in the
medical record.

    1.       1. For the first diagnostic facet joint procedure to be considered medically reasonable and necessary, the patient must meet the criteria outlined under indications for facet joint interventions.
      2. A second confirmatory diagnostic facet joint procedure is considered medically reasonable and necessary in patients who meet **ALL** the following criteria:
        1. The patient meets the criteria for the first diagnostic procedure; **AND**
        2. After the first diagnostic facet joint procedure, there must be a consistent positive response of at least 80% relief of primary (index) pain (with the duration of relief being consistent with the agent used) 
********

_Frequency Limitation_ : For each covered spinal region no more than 4
diagnostic joint sessions will be reimbursed per rolling 12 months, in
recognition that the pain generator cannot always be identified with the
initial and confirmatory diagnostic procedure.

  2. **Therapeutic Facet Joint Procedures (IA):**

Therapeutic facet joint procedures are considered medically reasonable and
necessary for patients who meet **ALL** of the following criteria:

    1.       1. The patient has had 2 medically reasonable and necessary diagnostic facet joint procedures with each 1 providing a consistent minimum of 80% relief of primary (index) pain (with the duration of relief being consistent with the agent used) **AND**
      2. Subsequent therapeutic facet joint procedures at the same anatomic site results in at least consistent 50% pain relief for at least 3 months from the prior therapeutic procedure **or** at least 50% consistent improvement in the ability to perform previously painful movements and activities of daily living (ADLs) as compared to baseline measurement using the same scale; **AND**
      3. Documentation of why the patient is not a candidate for RFA (such as established spinal pseudarthrosis, implanted electrical device)

_Frequency Limitation_ : For each covered spinal region no more than 4
therapeutic facet joint (IA) sessions will be reimbursed per rolling 12
months.

  3. **Facet Joint Denervation:**

The thermal radiofrequency destruction of cervical, thoracic, or lumbar
paravertebral facet joint (medial branch (MB)) nerves are considered medically
reasonable and necessary for patients who meet **ALL** the following criteria:

    1.       1.  Initial thermal RFA: 
        1.  After the patient has had at least 2 medically reasonable and necessary diagnostic MBBs, with each 1 providing a consistent minimum of 80% sustained relief of primary (index) pain (with the duration of relief being consistent with the agent used); **AND**
        2. Repeat thermal facet joint RFA at the same anatomic site is considered medically reasonable and necessary provided the patient had a minimum of consistent 50% improvement in pain for at least 6 months **or** at least 50% consistent improvement in the ability to perform previously painful movements and ADLs as compared to baseline measurement using the same scale

_Frequency Limitation_ : For each covered spinal region no more than 2
radiofrequency sessions will be reimbursed per rolling 12 months.

  4. **Facet Cyst Aspiration/Rupture:**

IA facet joint injection performed with synovial cyst aspiration is considered
medically necessary when both of the following criteria are met:

  1.     1. Advanced diagnostic imaging study (e.g., magnetic resonance imaging (MRI)/ computed tomography (CT)/myelogram) confirms compression or displacement of the corresponding nerve root by a facet joint synovial cyst; **AND**
    2. Clinical and physical symptoms related to synovial facet cyst are documented

_Frequency Limitation:_ Cyst aspiration/rupture may be repeated **once** and
only if there is 50% or more consistent improvement in pain for at least 3
months.

**Limitations**

  1. Facet joint interventions done without CT or fluoroscopic guidance are considered not reasonable and necessary. This includes facet joint interventions done without any guidance, performed under ultrasound guidance, or with MRI.
  2. General anesthesia is considered not reasonable and necessary for facet joint interventions. Neither conscious sedation nor monitored anesthesia care (MAC) is routinely necessary for IA facet joint injections or MBBs and are not routinely reimbursable. Individual consideration may be given on redetermination (appeal) for payment in rare, unique circumstances if the medical necessity of sedation is unequivocal and clearly documented in the medical record. Frequent reporting of these services together may trigger focused medical review. 
  3. It is not expected that patients will routinely present with pain in both cervical/thoracic and lumbar spinal regions. Therefore, facet joint interventions (both diagnostic and therapeutic) are limited to 1 spinal region per session.
  4. It is not routinely necessary for multiple blocks (e.g., epidural injections, sympathetic blocks, trigger point injections, etc.) to be provided to a patient on the same day as facet joint procedures. Multiple blocks on the same day could lead to improper or lack of diagnosis. If performed, the medical necessity of each injection (at the same or at different level[s]) must be clearly documented in the medical record. For example, the performance of both paravertebral facet joint procedure(s) and a transforaminal epidural steroid injection (TFESI) at the same or close spinal level at the same encounter would not be expected unless a synovial cyst is compressing the nerve root. In this situation, TFESI may provide relief for the radicular pain, while the facet cyst rupture allows nerve root decompression. Frequent reporting of multiple blocks on the same day may trigger a focused medical review.
  5. Facet joint IA injections and MBBs may involve the use of anesthetic, corticosteroids, anti-inflammatories and/or contrast agents, and does not include injections of biologicals or other substances not United States Food and Drug Administration (FDA) designated for this use.
  6. One to 2 levels, either unilateral or bilateral, are allowed per session per spine region. The need for a 3 or 4-level procedure bilaterally may be considered under unique circumstances and with sufficient documentation of medical necessity on appeal. A session is a time period, which includes all procedures (i.e., MBBs, IA injections, facet cyst ruptures, and RFAs) that are performed during the same day.
  7. If there is an extended time, 2 years or more, since the last RFA and/or there is a question as to the source of the recurrent pain then diagnostic procedures must be repeated.
  8. Therapeutic IA facet injections are not covered unless there is documentation on why RFA cannot be performed. Facet joint procedures in patients for the indication of generalized pain conditions (such as fibromyalgia) or chronic centralized pain syndromes are considered not reasonable and necessary. Individual consideration may be considered under unique circumstances and with sufficient documentation of medical necessity on appeal. 
  9. In patients with implanted electrical devices, providers must follow manufacturer instructions and extra planning as indicated to ensure safety of procedure.

The following are considered not reasonable and necessary and therefore, will
be denied:

  1. IA and extra-articular facet joint prolotherapy
  2. Non-thermal modalities for facet joint denervation including chemical, low-grade thermal energy (less than 80 degrees Celsius), laser neurolysis, and cryoablation
  3. Intra-facet implants
  4. Facet joint procedure performed after anterior lumbar interbody fusion (ALIF).
  5. Definitive clinical and/or imaging findings pointing to a specific diagnosis other than facet joint syndrome
  6. Diagnostic injections or MBB at the same level as the previously successful RFA procedure

**Note:** The scales used for measurement of pain and/or disability must be
documented in the medical record. Acceptable scales include but are not
limited to: verbal rating scales, Numerical Rating Scale (NRS) and Visual
Analog Scale (VAS) for pain assessment, and Pain Disability Assessment Scale
(PDAS), Oswestry Disability Index (ODI), Oswestry Low Back Pain Disability
Questionnaire (OSW), Quebec Back Pain Disability Scale (QBPDS), Roland Morris
Pain Scale (RDQ), Back Pain Functional Scale (BPFS), and the Patient-Reported
Outcomes Measurement Information System (PROMIS) profile domains to assess
function.

**Notice:** Services performed for any given diagnosis must meet all the
indications and limitations stated in this policy, the general requirements
for medical necessity as stated in CMS payment policy manuals, all existing
CMS national coverage determinations, and all Medicare payment rules.

**Provider Qualifications:**  
  
Medicare Program Integrity Manual states services will be considered medically
reasonable and necessary only if performed by appropriately trained providers.  
  
Patient safety and quality of care mandate that healthcare professionals who
perform facet injections/procedures are appropriately trained and/or
credentialed by a formal residency/fellowship program and/or are certified by
either an accredited and nationally recognized organization or by a post-
graduate training course accredited by an established national accrediting
body or accredited professional training program. If the practitioner works in
a hospital facility at any time and/or is credentialed by a hospital for any
procedure, the practitioner must be credentialed to perform the same procedure
in the outpatient setting. At a minimum, training must cover and develop an
understanding of anatomy and drug pharmacodynamics and kinetics as well as
proficiency in diagnosis and management of disease, the technical performance
of the procedure, and utilization of the required associated imaging
modalities.

In addition to the above requirements, non-physician providers, such as
certified nurse anesthetists, with certain exceptions, may certify, order and
establish the plan of care as authorized by state law. (See Sections
1861[s][2] and 1862[a][14] of Title XVIII of the Social Security Act; 42 CFR,
Sections 410.74, 410.75, 410.76 and 419.22; 58 FR 18543, April 7, 2000.) Each
practitioner must provide only those services within the scope of practice for
each state.

**Definitions**

**Acute pain** \- The temporal definition of pain persisting for up to 4 weeks
after the onset of the pain.

**Axial** \- Relating to or situated in the central part of the body, in the
head and trunk as distinguished from the limbs, e.g., axial skeleton.

**Biopsychosocial model** \- Interdisciplinary model that looks at the
interconnection between biology, pathology and socioenvironmental factors.

**Central neuropathic pain** \- Pain, which is causally related to a lesion or
disease of the central somatosensory nerves.

**Centralized pain** - A neurological chronic pain syndrome of the central
nervous system (brain, brainstem, and spinal cord) which commonly presents
with widespread generalized allodynia which is causally related to the
increased responsiveness of nociceptive nerves in the central nervous system
to the normal threshold or subthreshold simulation from the afferent nerves.
The condition has also been called "central sensitization," "central
amplification," and "central pain syndrome." Fibromyalgia is considered one of
the most common centralized pain syndromes.

**Cervical facet pain** \- Pain located in the cervical spine, which may be
characterized by chronic headaches, restricted motion, and axial neck pain,
which may radiate sub-occipitally to the shoulders or mid-back.

**Chronic pain** \- The temporal definition of pain persisting for greater
than or equal to 12 weeks after the onset of the pain.

**Dual diagnostic blocks  **\- The diagnostic technique of injecting the same
spinal nerve on 2 separate occasions to be used as an efficacy comparison to
increase diagnostic accuracy.

**Epidural steroid injection  **\- The administration via injection of steroid
medicine into the potential epidural space in the spinal column to deliver
steroids to the spinal nerves.

**Facet joint intra-articular injections, diagnostic** \- The placement of
local anesthetic and possibly a corticosteroid into the facet joint to
diagnose facet joint pain.

**Facet joint intra-articular injections, therapeutic** \- The placement of
local anesthetic and possibly a corticosteroid into the facet joint to produce
the beneficial effect of pain reduction.

**Facet joint** \- A diarthrodial joint in the spinal column (also called the
zygapophysial joint or z-joint), producing the articulation of the posterior
elements of 1 vertebra with its neighboring vertebra. They are bilateral
superior and inferior articular surfaces at each spinal level. The terminology
or nomenclature of the facet joint is classified by the specific vertebrae
level that forms it (e.g., C4-5 or L2-3). There are 2 facet joints, right and
left, at each spinal level.

**Facet injection (also called facet block)** \- A general term used to
describe the injection of local anesthetic and possibly a corticosteroid in
the facet joint capsule or along the MB nerves supplying the facet joints.

**Facet joint denervation or radiofrequency ablation (RFA)** \- A general term
used to describe the minimally invasive procedure that uses thermal energy
generated by the radiofrequency current to deprive the facet joint of its
nerve supply. The procedure is also known as a MB radiofrequency neurotomy
(ablation) because it is used to thermally remove the MB nerve by using
electrical current to create thermal energy to coagulate the adjacent tissues
around the targeted MB nerve.

**Facet joint syndrome  **\- A set of concurrent signs or symptoms to describe
facet joint pain as the pain generator. The typical clinical signs or symptoms
of a facet syndrome may include local paraspinal tenderness; pain that is
brought about or increased on hyperextension, rotation, and lateral bending;
low back stiffness; absence of neurologic deficit; absence of root tension
signs (non-radiating below the knee, absence of paresthesia). Cervical facet
pain is often characterized by chronic headaches, restricted motion, and axial
neck pain, which may radiate sub-occipitally to the shoulders or mid-back.

**Facet level  **\- Refers to **** the zygapophyseal joint or the 2 MB nerves
that innervate that zygapophyseal joint. Each level has a pair of facet
joints: 1 on the right side and 1 on the left side of the spine.  

**Intra-articular injection (IA)  **\- The injection of local anesthetic and
possibly a corticosteroid into the facet joint capsule.

**Medial branch (MB)** \- The dorsal ramus is the dorsal branch of a spinal
nerve that forms from the dorsal root of the nerve after it emerges from the
spinal cord.  

**Medial branch block (MBB)** - The placement of local anesthetic and possibly
a corticosteroid near the MB nerve which supplies the sensory innervation to a
specific facet joint.

**Neuropathic pain** - The pain which is caused by a lesion or disease of the
somatosensory nerves.

**Neurogenic claudication -** Intermittent leg pain from impingement of the
nerves emanating from the spinal cord (also called pseuduoclaudication).

**New onset of spinal pain**  \- The new onset of the spinal pain must be
materially and significantly different in location, type, duration and
character from the previously treated spine pain.

**Non-invasive conservative management** \- The use of nonsteroidal anti-
inflammatory drugs (NSAIDs), acetaminophen, physical therapy, acupuncture
(applies to only chronic low back pain), or spinal manipulation. This
management should include the application of biopsychosocial treatment
techniques.

**Non-radicular back pain** \- The radiating non-neuropathic pain which is not
causally related to a spinal nerve root irritation and does not produce
reproducible neuropathic symptoms in an objective dermatomal pattern.

**Peripheral neuropathic pain** \- Pain, which is causally related to a lesion
or disease of the peripheral somatosensory nerves.

**Radicular back pain** \- The radiating neuropathic pain causally related to
the spinal nerve root irritation which extends into the distal distribution,
typically the lower extremity, producing neuropathic pain in a dermatomal
pattern.

**Radiculopathy**   **-** Radiating neuropathic pain causally related to the
spinal nerve root irritation, which extends distal producing neuropathic pain
in a dermatomal pattern.

**Region -** The segments of the back involved will be defined in this policy
as 2 regions:

  1. Cervical/Thoracic region= C1-C7/T1-T12
  2. Lumbar/Sacral region= L1-L5/S1-S5

**Session** \- A time period, which includes all procedures (i.e., MBBs, IA
injections, facet cyst ruptures, and RFAs) performed during 1 day.

**Subacute pain** \- The temporal definition of pain occurring during the
4-12-week time period.

**Transforaminal epidural steroid injection (TFESI)** \- An epidural injection
performed via a paramedian approach to enter the epidural space by placing the
needle in the posterior-superior quadrant of the intervertebral foramen
(neuroforamen) to inject near the dorsal root ganglion and exiting spinal
nerve root (previously known as a selective nerve root block).

**Zygapophysial joint or z-joint** \- See Facet joint.



**History/Background and/or General Information**

The spine is the most common source of chronic pain. Chronic axial spinal pain
is one of the major causes of disability and accounts for a substantial United
States (U.S.) health burden. Chronic spine pain poses a peculiar diagnostic
and therapeutic challenge due to multiple pain sources, overlapping clinical
features, and nonspecific radiological findings.

The facet joints can cause axial spinal pain and referred pain in the
extremities. The pathology of the pain source is due to facet joints being
richly innervated by the nerve fibers from the MB of the dorsal ramus of
spinal nerves. Each facet has a dual nerve supply. One exception is at the
C2-C3 zygapophysial joint, which has a singular nerve supply from the third
occipital nerve (the superficial MB of C3 dorsal ramus).1

Facet joint interventions may be used in pain management for chronic
cervical/thoracic and back pain arising from the paravertebral facet joints.
The facet block procedure is an injection of a local anesthetic, with or
without a steroid medication, either into the facet joint (IA) or outside the
joint space around the nerve supply to the joint (the MB nerve) known as
medial branch block (MBB). Imaging guidance (fluoroscopy or CT per code
descriptor) is used to assure accurate placement of the needle for the
injection. Paravertebral facet joint denervation is a therapeutic intervention
used to provide both long-term pain relief and reduce the likelihood of
recurrence of chronic cervical/thoracic or back pain confirmed as originating
in the facet joint's MB nerve.1

There are various methods that may be used in performing facet joint
denervation. Percutaneous RFA is a minimally invasive procedure done with
imaging guidance (fluoroscopy or CT per code descriptor) and involves using
energy in the radiofrequency range to cause necrosis of specific nerves (MBs
of the dorsal rami), preventing the neural transmission of pain. Conventional
RFA (non-pulsed or continuous) applies thermal energy of typically 80 to 85
degrees Celsius. The terms RFA and radiofrequency neurotomy are used
interchangeably. Both terms refer to a procedure that destroys the
functionality of the nerve using radiofrequency energy. Non-thermal methods of
denervation include chemical (chemodenervation), low-grade thermal energy
(less than 80 degrees Celsius), pulsed RFA, laser neurolysis, and
cryoablation.1

Throughout this document, societal recommendations with the grading of
evidence are referenced. There are multiple systems to grade or rank the
quality of medical evidence and develop evidence-based recommendations. Not
all grading systems are equivalent, so while there are typically similarities
in the grades or recommendations from various grading systems, they must be
considered independent of the other. The references in this document refer to
the following grading systems:

  1. Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) Guidelines used in some systematic reviews, the basis for North American Spine Society (NASS) recommendations aligns with GRADE.

  2. A modified approach to the grading of evidence2 and development of interventional pain management specific instrument3 used in American Society of Interventional Pain Physicians (ASIPP) Guidelines and some systematic reviews.

  3. U.S. Preventive Services Task Force grading of evidence guidelines used by 2020 Consensus Guidelines by Cohen, et al.4

  4. Levels of Evidence for Primary Research Question and Grades of Recommendation for Summaries or Review of Studies adopted by NASS.5

A multi-MAC Subject Matter Expert (SME) panel on facet joint and medial nerve
branch procedures meeting was held on 5/28/2020.

_Diagnostic Facet Joint Injections_

Due to the lack of reliable history, physical exam, or imaging to predict
response, providers must rely on facet interventions diagnostic injections
given for diagnostic purposes to determine if the facet joint is the source of
suspected spinal pain. There is controversy over optimal patient selection for
diagnostic injections, which measures successful response and type and number
of diagnostic injections performed.

Numerous investigations have been undertaken to correlate symptoms and
physical exam findings with facet pathology and have concluded conventional
clinical findings are unreliable in identifying facet joint success.4,6,7 A
2020 summary of the literature by Cohen, et al. "Consensus practice guidelines
on interventions for lumbar facet joint pain from a multispecialty,
international working group" (2020 Consensus Guidelines) included 21 studies
evaluating the association of physical exam findings with facet block results,
and conclude there was no historical or physical exam findings that could
reliably predict response to facet joint blocks, grade C evidence, low level
of certainty.4 This is consistent with ASIPP 2020 "Comprehensive Evidence-
Based Guidelines for Facet Joint Interventions in the Management of Chronic
Spinal Pain: American Society of Interventional Pain Physicians (ASIPP)
Guidelines" (2020 ASIPP Guidelines) which rated accurate diagnosis of facet
joint pain with physical examination and symptoms level IV with a weak
strength of recommendation.7 2020 NASS Guidelines reported insufficient
evidence to make a recommendation for or against patient-reported reproduction
of pain during a facet joint injection as a predictor of response to dual
diagnostic blocks with a grade 1 recommendation.5,7 A careful medical history
and exam remain an important component to the evaluation of other etiologies
of low back pain and raise suspicion of facet source.7 Physical findings can
help identify levels for blocks, and maneuvers can aid in the detection of
radicular symptoms.4

Imaging studies have been investigated as a marker of painful lumbar facet
joints. While degenerative changes can be found in imaging, they have not been
correlated as a reliable predictor of success with facet interventions.4,7
Nonetheless, imaging studies often play an important role in the exclusion of
other etiologies of back and cervical/thoracic pain. Single-photon emission
computed tomography (SPECT), a nuclear medicine imaging technique, can
identify active inflammatory markers as seen in facet disease but have not
shown consistent results in the prediction of facet joint intervention
success. 2020 Consensus Guidelines reported on 12 studies and concluded
moderate evidence for SPECT (grade C, moderate certainty) and weak evidence
for scintigraphy, MRI, and CT with no to weak supporting evidence.4 2020 ASIPP
Guidelines reported level III evidence for SPECT with weak strength of
recommendation and level V evidence for other imaging modalities, weak
recommendation.7

Conservative treatment, also called medical/interventional treatment, includes
integrative treatments (such as acupuncture (see NCD 30.3) or spinal
manipulation); physical treatments (physical therapy including exercise, heat
and cold modalities, massage), medications (NSAIDS/antidepressants), and
lifestyle modifications (weight loss, sleep hygiene, nutrition, smoking
cessation) are typically perused before interventional procedures. Facet joint
pain is frequently accompanied by other pain etiologies, which may benefit
from conservative modalities or combined therapy, and it is well accepted that
some back pain will resolve spontaneously or with conservative or non-invasive
measures over time. A few studies have had a conservative arm, or investigated
combined modalities that support a combined approach, but did not find a
conservative approach alone consistently lead to improvement.5,8 The Agency
for Healthcare Research released a systematic review of non-invasive, non-
pharmacological treatment for chronic pain, including neck and low back. Two
hundred two trials were included which evaluated the spectrum of non-invasive
treatment modalities, concluded durable slight to moderate improvement in
function and pain for specific chronic pain conditions and support clinical
strategies that focus on non-pharmacological and non-invasive therapies.9,10
2015 NASS Guidelines recommend a failure of at least 4 weeks of non-invasive
care11; Spou 2020 Consensus Guidelines recommend a 3-month trial of different
non-invasive treatment4; 2020 ASIPP Guidelines rated level of evidence II with
a strong recommendation for 3 months after onset and failure of conservative
management;7 European Guidelines extend the period to 1 year.12 Chronic pain
may lead to stress, anxiety, poor sleep and depression, and other
psychological sequalae and treatment beyond the pain symptoms may be
necessary. Optimally a biopsychosocial model that promotes a multi-
disciplinary team approach addressing physical pain and psychological factors
are utilized.13 Patients with chronic pain may also benefit from cognitive
behavioral therapy, biofeedback, and other psychological interventions.14

Due to the lack of reliable history, physical exam, or imaging to predict
response to facet interventions, diagnostic injections may be given for
diagnostic purposes to determine if the facet joint is the source of suspected
spinal pain. The response pattern to diagnostic facet joint injections has
become the gold standard for diagnosing facet syndrome. Temporary or prolonged
abolition of the spinal pain suggests that facet joints were the source of the
symptoms.1 The possibility of false-positive and false-negative reporting is
an inherent risk with facet blocks and challenges identifying the patients
most likely to have a positive response to treatment.4,7 IA and MBBs have been
evaluated for predictive value for successful RFA. 2020 ASIPP Guidelines
reported on 10 studies in the lumbar spine and found prevalence rates ranged
from 27% to 40% with false-positive rates of 27% to 47%, with  80% pain
relief. They conclude level 1-2 evidence with moderate to strong strength of
recommendation of lumbar, diagnostic facet nerve blocks.7 While both IA and
MBBs have been shown in studies to be predictive of success with RFA (2020
Consensus Guidelines grade B recommendation, low level of certainty)4 5
studies comparing lumbar MBB to IA injections, including 2 randomized
studies15,16 supports MBB as the preferred modality, largely due to high
technical failure rate and pain associated with the IA injections. One
randomized trial focusing on younger patients shows IA injection with steroids
may play a role in patients in which MBB is contraindicated (grade C evidence,
moderate certainty).4 The Greater Manchester EUR Policy Statement on Facet
Injections no longer commissioned IA facet injections and recommended MB nerve
blocks for diagnostic evaluation for RFA.12 The Spinal Intervention Society
(SIS) recommended that MBBs replace IA injections as a diagnostic indicator.1

In order to determine if a block is successful, there must be an
assessment/measurement of pain and function. There are 3 points in which
pain/function must be evaluated: 1. baseline; 2. after a diagnostic block; and
3. at each follow-up to evaluate long term relief. The definition of success
lacks consistency, and there are different cut-off values in the literature.
Among the multi-MAC SME panel, there was an agreement that subjective
improvement in pain is a valid measurement of improvement in pain (average
voting score of 3.8/5). However, there was not agreement on what the cut-off
should be, if a tool should be used, and if so, which tool. There was also a
consensus that function is the most important indicator of success. A study
assessed the validity of subjective rating improvement after 1 IA joint
injection and compared subjective rating to use of VAS scoring and concluded
that validity of pain provocation alone as criterion standards in patients
undergoing diagnostic facet injections should be questions with the positive
predictive value of 16% for predicating facet joint as a source of pain.17
Clinical trials and policy have used multiple standardized tools to measure
pain, including the NRS and VAS, with pre-set cut-off values in attempt to
determine a specific measurement in which patient's may most benefit from
intervention. Studies have evaluated if a specific cut-off value can predict
outcomes of RFA and do report a high correlation between verbal rating scales,
NRS and VAS score in prediction of outcomes with RFA. However, the panel did
not agree on a minimum value that can be used with these tools. The panel did
agree that measurement of function can provide valuable clinical input into
improvement, such as the ability to stand, walk, and the ability to do ADLs
and can predict success with future therapeutic procedures. There are multiple
tools to measure function including the PDAS,18 ODI,19 OSW, QBPDS,20 RDQ,21
BPFS,22 and the easy-to-use PROMIS profile domains which have been found to
correlate well with the ODI scale.23

For the diagnostic block, the pain relief achieved is temporary and used as a
predictor of success for subsequent RFA. The objective is to reduce false-
positives that would not be predictive of success with RFA and avoid false-
negative patients who could benefit but would not be offered treatment. Most
studies have used a cut-off of pain relief greater than 80% to consider MBB as
positive. Ten studies assessing the prevalence of lumbar facet joint pain
using a cut-off value of 80% relief reported with a prevalence rate of 27% to
40% with false-positive rates of 27% to 47% receiving a moderate to strong
recommendation from 2020 ASIPP Guidelines.7 One paper reports dual comparative
blocks are advocated as a means of identifying true-positive cases and
excluding placebo responders and have been shown to have a sensitivity of 100%
and a specificity of 65%.24

As stated in the 2020 Consensus Guideline: "the cut-off designating an MBB as
positive is one of the most controversial areas in pain medicine."4 Cohen, et
al. in 2013, prospective study to evaluate predictive values and reported no
difference in the predictive value of  50% to <80% pain reduction vs. 80%
pain reduction.25 The guidelines advocate for using 50% for clinical trials
and clinical practice. The guidelines acknowledge that the existing evidence
does not adequately address the 50-80% group and that this cut-off was
selected to maximize access to care given the lack of reliable alternative
treatment options in this population and potential benefit of treatment in
this group.4 On the contrary, there are studies that show patients with 80%
relief are more likely to show a positive response to RFA. 2020 ASPP
Guidelines report level 1 to II evidence based on 10 diagnostic accuracy
studies (using 75% and 80% criterion) and offer moderate to strong strength
of recommendation. They cite the literature using the 50% cut-off is
conflicting due to internal inconsistencies.7

There is controversy regarding the number of diagnostic blocks needed to
ensure an accurate diagnosis before proceeding with RFA. Derby, et al.
evaluated the correlation of lumbar MBB with diagnostic MBB cut-off values to
optimize therapeutic outcomes and a failure of single MBB and conclude with a
dual block protocol a 70% cut-off value was acceptable. With a single block,
80% or higher was optimal.26,27 Three systematic reviews also showed
significantly better improvement with dual MBB with 80% cut-off value.28-30
Two randomized controlled trials (RCTs) (1 in the cervical region)
demonstrated positive results with dual blocks.31,32 SIS and ASIPP advocate
for dual diagnostic blocks, and diagnostic accuracy is reduced if lower cut-
off criteria are used. In contrast, the 2020 Consensus Guidelines advocate for
single blocks using a 50% cut-off. One RCT compared outcomes of stratified by
different prognostic values and reported the success rate in those who
underwent RFA in the zero (no block), single and double block groups were 33%,
39%, and 64%, respectively.33 Another study reporting on success rates of RFA
based on the number of blocks concludes no difference in outcomes based on the
number of blocks.34 A meta-analysis of 5 RCTs using zero or 1 block favored
RFA.35 However, a meta-analysis is challenging given the high heterogenicity
of the literature. The 2020 Consensus Guidelines suggest the number of blocks
depends on the goals with dual blocks preferable for research where diagnostic
accuracy is critical while single (or no) blocks reduce the number of
procedures and access to care. Balancing these factors, they recommend a
single block reporting moderate evidence that dual blocks result in higher
success with RFA, but zero-block results in the highest number of patients
with a positive response to RFA.4 The result of voting from the multi-MAC SME
panel was a score of 3.2/5, stating confidence in the clinical literature to
support 2 MBBs needed to diagnose facet pain. NASS Guidelines recommend dual
MBBs on 2 separate occasions and second block administered only if >80% relief
with the first block due to an unacceptably high false-positive rate of single
diagnostic injection.11 In the 2020 NASS Evidence-Based Clinical Guidelines
for Multidisciplinary Spine Care, they state a single diagnostic IA injection
with 50% pain relief provides no clinically meaningful improvement at 6 months
(grade of recommendation B) and insufficient evidence to make a recommendation
for or against the use of RFA (grade of recommendation I (Insufficient)).5

The literature and societal guidance report that diagnostic injections should
be MBBs, not IA injections. This is agreed upon in the 2020 Consensus
Guidelines, 2020 ASIPP Guidelines, and NASS Guidelines. NASS Guidelines state
IA facet injections have not been validated for diagnostic use, and the false-
positive rate is unknown, as well as lack of effectiveness studies comparing
IA vs. MBB in the cervical spine.11 The exceptions in the case of the
occipitoatlantal and atlantoaxial joints, since there are no MB or other
intervention to block readily. In these cases, dual blocks with 80% relief are
supported by most guidelines.5

****

_Therapeutic Joint Injections_

IA injections into the facet joint have been used as a treatment modality for
facet related pain and remains controversial. Therapeutic injections typically
include a corticosteroid as there would not be anticipated long-acting pain
relief from a short-term local anesthetic. Among the multi-MAC SME panel, the
average voting was 2.70, with a range from 1-4. There is clinical evidence
against the use of IA therapeutic facet joint injections. Lilius, et al.
conducted an RCT including 109 patients who failed to show a difference
between saline, steroids, and anesthetic injected around 2 facet joints.36
Carette, et al. conducted an RCT, including 101 patients with IA lumbar facet
pain, that showed a non-significant difference between the injection of saline
and depo-corticosteroid with 22% in steroid group compared to 5% in saline
group reporting benefit at 6 months.37 A small RCT, including 41 patients,
reported return of pain in 3 days after IA steroid injection compared to 3.5
days in the control.38 Kennedy, et al. performed a small RCT comparing IA
facet injections with a steroid to saline and did not find a change in need
for RFA.39 In the Facet Treatment Study (FACTS), a double-blinded RCT, Cohen,
et al. found no significant difference for pain relief or functional outcome
change between lumbar facet IA injection with steroid or anesthetic or MBB
with steroid, anesthetic or saline for up to 6 months post-injection. Five
patients made it to the 6-month follow-up, of which 2 had RFA. The FACTS study
also found that MBB for anesthetic or steroids did not perform better than
saline.12

On the contrary, a systematic review by Manchikanti, et al. (2015) using a
modified approach to the grading of evidence,6 reported 20 RCTs assessed with
moderate to high-quality methodological criteria. For therapeutic
interventions, the evidence was variable from level II to III, with level II
evidence for lumbar facet joint nerve blocks and radiofrequency neurotomy for
long-term improvement (greater than 6 months), and level III evidence for
lumbosacral zygapophysial joint injections for short-term improvement only.
This review provides evidence for the diagnostic validity of facet joint nerve
blocks, and moderate evidence for therapeutic radiofrequency neurotomy and
therapeutic facet joint nerve blocks in managing chronic low back pain.6 These
2 studies have been criticized for a high proportion of patients taking
opioids and prior back surgery, lack of control groups, and the absence of
blinding.4 Schneider, et al. reported in rigorously selected patients, 56% of
patients had 100% pain relief at 6 months.40 A systematic review by Engel
reported sustained relief of 6 months, and 1/3 had relief at 1 year.29

This is in contrast with another systematic review during the same period that
looked at the evidence supporting the use of therapeutic IA facet joint
injections for patients with suspected facet joint pain. The review focused on
IA facet joint injections with active drug or placebo/inactive injection are
more effective in reducing back pain and back pain-related disability than
conservative treatment. A total of 391 records were screened, and 6 trials
were included. The trials included were small (range 18-109 participants), and
overall, in terms of pain and disability outcomes, most were inconclusive.
Only 2 of the trials report any significance between the group's differences
in pain or disability outcomes. The authors addressed the limitations and
flaws in these trials that were clinically diverse and precluded any meta-
analysis. Several methodological issues were identified. The positive results
are interpreted with caution and suggest that there is a need for further
high-quality work in this area.41

Many societal recommendations that do not support the use of therapeutic facet
joint injections include:

  * The 2020 Consensus Guidelines developed by a multispecialty international working group recommend against the routine use of therapeutic facet injections giving it a grade D, moderate level of certainty.4
  * National Institute for Health and Care Excellence (NICE) guideline on low back pain and sciatica in over 16s: assessment and management42 recommendations are based on systematic reviews of best available evidence and explicit consideration of cost effectiveness. The NICE recommendation for image-guided facet joint injections "do not offer spinal injections for managing low back pain. The Guideline Development Group (GDG) agreed that health-related quality of life, pain severity, function, and psychological distress were the outcomes that were critical for decision making. Responder criteria (greater than 30% improvement in pain or function), adverse events, and healthcare utilization were also considered as important. Evidence was reported for all the outcomes except for psychological distress and healthcare utilization. For image-guided facet joint injections, evidence was only available for pain, function, and responder criteria. There was no evidence for any of the other outcomes." The NICE summary concludes: "Overall, the GDG agreed that there was no consistent good quality evidence to recommend the use of spinal injections for the management of low back pain. There was minimal evidence of benefit from injections, and reason to believe that there was a risk of harm, even if rare. The GDG consequently agreed that it was appropriate to recommend against the use of spinal injections for people with low back pain."
  * The American Association of Neurological Surgeons (AANS) and the Congress of Neurological Surgeons (CNS) 2014 Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine: Part 13: injection therapies, low-back pain, and lumbar fusion. Lumbar IA facet injections are not recommended for the treatment of chronic lower-back pain. The literature does suggest the use of lumbar medial nerve blocks for short-term relief of facet-mediated chronic lower-back pain without radiculopathy.43
  * NASS Evidence-Based Clinical Guidelines for Multidisciplinary Spine Care: Diagnosis and Treatment of Degenerative Lumbar Spondylolisthesis 2nd Edition (2014) reports that there is insufficient evidence to make a recommendation for or against the use of injections for the treatment of degenerative lumbar spondylolisthesis. Grade of recommendation: I (Insufficient Evidence).11 The 2020 NASS Low Back Pain Guidelines states there is insufficient evidence to make a recommendation for or against the use of steroid injections for suspected facet-mediated pain (grade 1 recommendation) nor sufficient evidence for or against the use of 50% reduction in pain following MBB for diagnosis of facet joint pain (grade 1 recommendation). The guidelines also state that the outcomes of RFA become more reliable when more stringent diagnostic criteria are used, and relief is durable for at least 6 months following procedure (grade B recommendation).5 NASS Guidelines state while there is some evidence in the literature when compared to RFA, RFA offers longer-term pain relief, and long-term outcomes have not been reported in adequately designed trials. They state that if therapeutic IA injections are used, they should be used in patients whose initial injections resulted in pain relief >50% for at least 3 months and not be repeated more than 3 times annually. The guidelines address concern of the majority of research on therapeutic MBBs comes from a single-center, reports on prospective studies and 1 RCT which had unspecified intervals and cannot determine the true duration of treatment and concern with lack of studies comparing therapeutic MBBs to MB RFA.5,11
  * Agency for Healthcare Research and Quality (AHRQ) Technology Assessment Program: Pain Management Injection Therapies for Low Back Pain (2015) authors used predefined criteria and selected randomized trials of patients with lumbosacral radiculopathy, spinal stenosis, nonradicular back pain, or chronic postsurgical back pain that compared effectiveness or harms of the epidural, facet joint, or sacroiliac corticosteroid injections versus placebo or other interventions. Also included were randomized trials that compared different injection techniques and large (sample sizes greater than 1000) observational studies of back injections that reported harms. Seventy-eight randomized trials of epidural injections, 13 trials of facet joint injections, and 1 trial of sacroiliac injections were included. Limited evidence suggested that epidural corticosteroid injections are not effective for spinal stenosis or nonradicular back pain and that facet joint corticosteroid injections are not effective for presumed facet joint pain.44
  * A 2009 American Pain Society guideline recommends against the use of corticosteroids into the facet joint.14 

Some societal recommendations that support the use of therapeutic facet join
injections include:

  * 2020 ASIPP Guidelines7: Therapeutic Facet Joint Interventions in Lumbar Spine states:
    * The level of evidence is II with moderate strength of recommendation for therapeutic lumbar facet joint nerve blocks with the inclusion of 3 relevant RCTs with long-term improvement.
    * The level of evidence is IV with a weak strength of recommendation for lumbar facet joint IA injections with inclusion of 9 relevant RCTs, with most of them showing lack of effectiveness without the use of local anesthetic.

The American Society of Anesthesiologists (ASA) Task Force on Chronic Pain
Management and the American Society of Regional Anesthesia and Pain Medicine
(ASRA) Practice Guidelines for Chronic Pain Management (2010)45:

  * Recommendations for joint blocks: RCTs report equivocal findings regarding the efficacy of facet joint steroid injections compared with facet saline injections regarding pain relief for patients with low back pain. However, studies with observational findings for facet joint injections indicate that pain scores are improved over baseline scores for assessment periods of 1-6 months. IA facet joint injections may be used for symptomatic relief of facet-mediated pain. MBBs may be used for the treatment of facet-mediated spine pain.

AANS and CNS 2014 Guideline update for the performance of fusion procedures
for degenerative disease of the lumbar spine. Part 13: injection therapies,
low-back pain, and lumbar fusion states lumbar IA facet injections are not
recommended for the treatment of chronic lower-back pain. The literature does
suggest the use of lumbar medial nerve blocks for short-term relief of facet-
mediated chronic lower-back pain without radiculopathy.43

_Radiofrequency Ablation_

__

Radiofrequency neurotomy is described as radiofrequency lesioning performed
utilizing either a heat lesion or pulsed mode radiofrequency. A thermal
radiofrequency neurotomy lesion for facet denervation is performed at 80 to
85C. Clinically, a higher temperature allows for a larger lesion to be made.
The size of the lesion is influenced by the vascularity of the surrounding
tissue: the greater the vascularity of the tissue, the smaller the lesion.
Overall, the mechanism of radiofrequency neurotomy is described as denaturing
of the nerves. Consequently, with radiofrequency, the pain returns when the
axons regenerate, requiring repetition of the radiofrequency procedure. The
pulsed mode radiofrequency is an application of a strong electric field to the
tissue that surrounds the electrode, and the temperature of the tissue
surrounding the tip of the electrode does not exceed 42C and heat is
dissipated during the silent period.7

The effectiveness of RFA to improve pain and function for facet joint mediated
back pain in carefully selected individuals has been explored in the medical
literature. Clinical trials report conflicting data on the effectiveness of
RFA. Most clinical trials defined success with RFA as 50% pain relief at 6
months.

A 2015 Cochrane review by Maas, et al., including 23 RCTs (n=1309), evaluated
patients who had a positive response to diagnostic block and underwent RFA
found moderate evidence on the effectiveness of RFA compared to placebo for
pain management of facet origin over the short term (mean difference (MD)
-1.47, 95% confidence interval (CI) -2.28 to -0.67). Low-quality evidence that
facet joint RFA is more effective than placebo for function over the short
term (MD -5.3, 95% CI -8.66 to -0.20) and over the long term (MD -3.9, 95% CI
-6.94 to 0.47). RFA for disc pain did not show effects compared to placebo
over the short or long term (MD -1.63, 95% CI -2.58 to -0.68). They concluded
no high-quality evidence to suggest RFA procedure provides pain relief for
patients with chronic low back pain.46

Juch, et al. reported on 125 patients in the treatment arm and 126 in the
control arm (exercise). Patients had a single diagnostic block with at least
50% or more pain reduction before RFA. The MD for the primary outcome pain
intensity at 3 months was 0.18 (95% CI, 0.76 to 0.40). The MD for functional
status at 3 months was 2.45 (95% CI, 5.53 to 1.03); the relative risk (RR)
for global perceived recovery at 3 months was 1.35 (95% CI, 0.81 to 2.05).
This study has been challenged, stating that the lack of efficacy was due to
the treatment arm using the perpendicular technique.47 Perpendicular electrode
placement has been questioned with concern it may fail to reach the target
nerve or only capture a segment, while parallel electrode placement reliably
captures the target nerve and does so along a substantial length of the nerve.
Those who challenge these studies report there are 3 studies (1999-2008) that
utilized the parallel technique that would result in positive outcomes and
report support for RFA from these trials.47 There are no recent trials that
address this controversy.

Leggett, et al. (2014) conducted a systematic review to determine the efficacy
of RFA for chronic low back pain associated with lumbar facet joints,
sacroiliac joints, discogenic low back pain, and the coccyx. Included articles
were sham-controlled RCTs, assessed the efficacy of RFA, reported at least 1
month of follow-up, and included participants who had experienced back pain
for at least 3 months. Eleven sham controlled RCTs were included: 3 studies
involving discogenic back pain, 6 studies involving lumbar facet joint pain,
and 2 studies involving sacroiliac joint pain. No studies were identified
assessing the coccyx. The evidence supports RFA as an efficacious treatment
for lumbar facet joint and sacroiliac joint pain, with 5 of 6 and both of the
RCTs demonstrating statistically significant pain reductions, respectively.
The evidence supporting the RFA for the treatment of discogenic pain is mixed.
Future studies should examine the clinical significance of the achieved pain
reduction and the long-term efficacy of RFA.48

The systematic review (2015) by Manchikanti, et al. looked at both therapeutic
injections, and RFA in lumbar, cervical and thoracic regions evaluated 21 RCTs
and 5 observational trials, using a modified approach to the grading of
evidence3, reported level II evidence2 for RFA in the lumbar and cervical
spine, and level IV in the thoracic region.28 A systematic review by Engel, et
al. (2016), which serves as the basis for NASS recommendations, "The
Effectiveness and Risks of Fluoroscopically-Guided Cervical Medial Branch
Thermal Radiofrequency Neurotomy: A Systematic Review with Comprehensive
Analysis of the Published Data" using the GRADE system for rating. They
conclude the majority of patients were pain-free at 6 months and over a third
pain-free at 1 year.29 In 2017, Lee, et al. conducted a meta-analysis that
included 7 trials with 454 patients comparing RFA (n=231) to sham or epidural
(n=223) and reported greater improvement in the RFA group.35

2020 ASIPP Consensus Guidelines7 Table 22 reports on 11 studies on RFA
effectiveness and concludes:

Lumbar Spine: The level of evidence is II with moderate strength of
recommendation for lumbar RFA with the inclusion of 11 relevant RCTs with 2
negative studies and 4 studies with long-term improvement.

****

ASA Task Force on Chronic Pain Management and ASRA Practice Guidelines for
Chronic Pain Management (2010) Recommendations for Ablative Techniques45: The
Task Force notes that other treatment modalities should be attempted before
consideration of the use of ablative techniques.

  * Chemical denervation: Chemical denervation (e.g., alcohol, phenol, or high-concentration local anesthetics) should not be used in the routine care of patients with chronic non-cancer pain.
  * Cryoablation: Cryoablation may be used in the care of selected patients (e.g., post-thoracotomy pain syndrome, low back pain (MB), and peripheral nerve pain).
  * RFA: Conventional (e.g., 80C) or thermal (e.g., 67C) RFA of the MB nerves to the facet joint should be performed for low back (MB) pain when previous diagnostic or therapeutic injections of the joint or MB nerve have provided temporary relief. Conventional RFA may be performed for neck pain. Conventional or thermal RFA of the dorsal root ganglion should not be routinely used for the treatment of lumbar radicular pain.

NICE guideline on low back pain and sciatica in over 16s: assessment and
management (2016) evidence statement49:

  * Radiofrequency denervation compared with placebo/sham for low back pain: Evidence from 4 studies demonstrated clinical benefit in pain for radiofrequency denervation compared to placebo/sham at both the short- and long-term follow-ups of less than and greater than 4 months (low to moderate quality, n=160). In contrast, there was no difference in function between treatments at any time point. Conflicting evidence from 1 study for quality of life at less than 4 months follow-up showed clinical benefit for radiofrequency denervation compared to placebo/sham for the Short Form 36-Health Survey (SF-36) domains of general health and vitality. Radiofrequency denervation was inferior to sham for the domains of mental health, pain, and social function. There was no difference between treatments for the physical domain (low quality, n=81).

Evidence from a single study reporting adverse events at less than 4 months
follow-up demonstrated an increase in adverse effects for radiofrequency
denervation in terms of the number of patients with moderate or severe
treatment-related pain (low quality, n=79). There was no difference in other
adverse events (change of sensibility and loss of motor function) at short-
term follow-up when radiofrequency denervation was compared to placebo/sham in
the same study (very low quality). Additionally, when compared with
placebo/sham, a benefit for radiofrequency denervation in responders to pain
reduction measured by global perceived effect was demonstrated by 2 studies at
both the less than and greater than 4 months follow-up time points. However,
this was not seen for pain reduction measured by VAS at less than 4 months
reported by a single study (low quality, n=111).

  * Radiofrequency denervation versus MBB: Evidence from a single study demonstrated clinical benefit in terms of pain for radiofrequency denervation compared to MBBs at both the short- and long-term follow-ups of less than and greater than 4 months (very low quality, n=100). Radiofrequency denervation has evolved as a treatment for spinal pain over the last 40 years and is a minimally invasive and percutaneous procedure performed under local anesthesia or light intravenous sedation. Radiofrequency energy is delivered along an insulated needle in contact with the target nerves. This focused electrical energy heats and denatures the nerve. This process may allow axons to regenerate with time, requiring the repetition of the radiofrequency procedure.
  * The duration of pain relief following radiofrequency denervation is uncertain. Data from RCTs suggests relief is maintained for at least 6-12 months, but no study has reported longer-term outcomes. Pain relief for more than 2 years would not be an unreasonable clinical expectation.

  * The de novo economic model undertaken for this guideline for radiofrequency denervation suggested that the treatment is likely to be cost-effective, provided the duration of effect exceeds 16 months.
  * If radiofrequency denervation is repeated, we do not know whether the outcomes and duration of these outcomes are like the initial treatment. If repeated radiofrequency denervation is to be offered, we need to be more certain that this intervention is both effective and cost effective.

NASS Guidelines state that therapeutic MB RFA is a validated treatment for
facet mediated pain, and repeat procedures are equally successful if the
response to the initial RFA lasted at least 3 months. These guidelines
advocate dual diagnostic MBB with 80% relief of the primary (index pain), and
the onset, and minimum duration of relief is consistent with the agent
employed. Also, RFA should be performed at the same level no more than twice
annually, and only if the initial radiofrequency lesion results in significant
pain relief (> 50%) for at least 6 months. In those situations, a repeat
procedure in that year is appropriate.15 2020 NASS Low Back Pain Guidelines
states there is insufficient evidence to make recommendations for or against
the use of cryodenervation for treatment of zygapophyseal (facet) joint pain.5

AANS and CNS 2014 Guideline update for the performance of fusion procedures
for degenerative disease of the lumbar spine. Part 13: injection therapies,
low-back pain, and lumbar fusion. Lumbar IA facet injections are not
recommended for the treatment of chronic lower-back pain. The literature does
suggest the use of lumbar medial nerve blocks for short-term relief of facet-
mediated chronic lower-back pain without radiculopathy. Lumbar medial nerve
ablation is suggested for 3-6 months of relief for chronic lower-back pain
without radiculopathy. Diagnostic medial nerve blocks by the double-injection
technique with an 80% improvement threshold are an option to predict a
favorable response to medial nerve ablation for facet-mediated chronic lower-
back pain without radiculopathy. Still there is no evidence to support the use
of diagnostic medial nerve blocks to predict the outcomes in these same
patients with lumbar fusion.43

__

_Cervical and Thoracic Spine_

Most of the literature focuses on the lumbar region regarding interventional
facet joint diagnosis, and the 2020 Consensus Guidelines are specific for the
lumbar region. The 2020 ASIPP Guidelines include the cervical and thoracic
regions. The 2020 ASIPP Guidelines report level I-II with moderate to strong
strength of recommendation for lumbar, diagnostic blocks report 10 diagnostic
accuracy studies to support the recommendation. ASIPP report level II evidence
for the cervical spine with moderate strength or recommendation citing 10
diagnostic accuracy studies. Two systematic reviews support reliance on dual
diagnostic blocks with 100% relief of the index pain to select patients for
the procedure reporting more than 60% selected using this stringent criterion
had 100% relief of index pain. They were pain-free at 6 months and nearly 40%
pain free at 1 year with functional improvement in neck pain.29,30

ASIPP (2020)7 Therapeutic Facet Joint Intervention Cervical Spine:

  * The level of evidence is II with moderate strength of recommendation for therapeutic cervical facet joint nerve blocks with the inclusion of 1 relevant RCT and 3 observational studies, with long-term improvement.
  * The level of evidence is V with weak strength of recommendation for cervical IA facet joint injections with the inclusion of 3 relevant RCTs, with 2 observational studies, the majority showing lack of effectiveness. In contrast, 1 study with a 6-month follow-up showed a lack of long-term improvement.
  * The level of evidence is II with moderate strength of recommendation for cervical RFA with the inclusion of 1 RCT with positive results and 2 observational studies with long-term improvement.

ASIPP (2020)7 Therapeutic Facet Joint Interventions Thoracic Spine:

Evidence to support use in the thoracic region is sparse. ASIPP reports level
II evidence with moderate strength recommendation for thoracic spine, citing 3
diagnostic accuracy studies.

  * The level of evidence is II with moderate strength of recommendation for thoracic therapeutic facet joint nerve blocks with the inclusion of 2 RCTs and 1 observational study with long-term improvement.
  * The level of evidence is III with weak to moderate strength of recommendation for thoracic IA facet joint injections with the inclusion of 1 RCT with a 6-month follow-up, with emerging evidence.
  * Thoracic Spine: The level of evidence is III with weak to moderate strength of recommendation with emerging evidence for thoracic RFA with the inclusion of 1 relevant RCT and 3 observational studies.

Evidence to support use in thoracic region is further supported by one 2012
systematic review report evidence for diagnostic accuracy of the thoracic
facet joint injection, and one 2018 study comparing thoracic IA vs. MBB
reporting significant pain relief with thoracic joint injection.50,51 NASS
guidelines state the lack of supporting literature for the use of IA
injections for thoracic pain, however, states the lack of other effective
alternative therapies.11

_Imaging_

****

Image guidance has become standard care for facet blocks and RFA procedures,
allowing accurate needle placement, monitor contrast and anesthetic spread,
and improve safety by direct visualization of bony elements and avoiding
surrounding structure. Studies dating back to the 1980s comparing "blind"
injections to image-guided concluded that the procedure should not be
performed without radiographical imaging. Fluoroscopy is considered the gold
standard for facet block procedures, and most studies were conducted with
fluoroscopic guidance and consistent with societal recommendations. The U.S.
Department of Health and Human Services Office of Inspector General (OIG)
report in 2008 asserted radiographic guidance is recommended.52 One cadaveric
study showed improved accuracy with fluoroscopy over CT.53 2020 Consensus
Guidelines recommend CT or preferably fluoroscopy for lumbar MBB (grade B
recommendation), CT scanning for IA placement (grade C recommendation), and
fluoroscopy for MB RFA (grade B recommendation, low level of evidence). The
guidelines state fluoroscopy is preferred to CT due to lower cost, faster
times, and less radiation exposure than CT.4

The use of ultrasound has been explored as an alternative imaging modality.
Cadaveric, retrospective studies, and review of RCT and non-RCT suggest that
there is little difference between ultrasound and fluoroscopy guided
procedures; however, there are no well-designed studies to report the safety
of this approach. Limitations for ultrasound guidance include reduced
visibility in obese patients, more challenging to target the proper segment,
and not being able to visualize facet joint.4 NASS Guidelines state
insufficient evidence to support use of ultrasound guidance.11 SMEs score low
confidence that the facet joint procedures can be performed under ultrasound
guidance (score 1.7/5).

_Facet Joint Cyst Rupture_

Facet joint cysts have been found to have a prevalence of 6.5% and are thought
to play a role in facet mediated pain. In these cases, nerve root compression
or irritation is associated with radicular pain like other neuro-compressive
lesions. Rupture of the cyst has been associated with pain improvement and may
potentially avoid more invasive open surgical procedures. In these cases, IA
injection is used and often with TFESI to treat radicular pain.11 A systematic
review of 870 patients report cyst resolution to be 58% for the percutaneous
procedure, and 90% for decompressive procedures concluding advantage of
surgical intervention as compared to percutaneous procedures and pain relief
with surgical management is estimated 83.5%. Shuang, et al. systematic review
of 29 studies reported overall the satisfactory results (after short- or long-
term follow-up) were achieved in 55.8% [49.5, 62.08] (pooled mean and 95% CI)
of the 544 patients subjected to percutaneous lumbar facet joint cyst
resolution procedures. 38.67% [33.3, 43.95] of this population underwent
surgery subsequently to achieve durable relief.54 However, the analysis
consisted largely of small retrospective studies and case reports with low-
quality evidence. In 1 prospective, non-randomized study, 120 patients'
satisfaction was reported as 75%, with 25% requiring repeat surgery.55 NASS
Guidelines address the concern of cyst reoccurrence, which occurs about 50% of
the time and does not recommend repeating the procedure more than once and
only if the first procure produces satisfactory results, which they define as
50% improvement for at least 3 months.11 The SME panel voted 3.9/5 in support
of facet joint cyst rupture for pain relief.

__

_Centralized Pain Syndrome_

__

Facet procedures by nature treat a local pain condition, while a centralized
pain syndrome, such as fibromyalgia, is a generalized pain condition. Patients
with centralized pain syndromes are thought to have alternations in central
neurotransmission. A prospective study with 548 patients diagnosed with
primary spine pain were also evaluated for fibromyalgia criteria before spinal
interventions. 42% of the patients meet diagnostic criteria for fibromyalgia.
They determined a profound phenotypic difference in those with fibromyalgia as
compared to those with spinal pain alone associated with more neuropathic pain
descriptors, anxiety, greater pain interference and lower physical function.
The authors concluded that the phenotypical factors found in the fibromyalgia
group may be predictive of poor outcomes in spine intervention procedures.56
Exploration of factors associated with poor outcomes from lumbar RFA and long
duration pain was correlated with treatment failure.57 There is insufficient
literature that addresses if facet joint procedures are beneficial for
centralized pain conditions.

****

_Intrafacet Implants_

Intrafacet implants have been proposed as an alternative technique to surgical
fusion. They involve the placement of an allograft dowel made from bone (from
femur or tibia) and placed surgically or via the minimally invasive procedure.
The allograft, which is processed by licensed tissue banks, which must be
compliant with FDA requirements for tissue processing, are not subject to FDA
510K clearance and can be marketed. There are no clinical trials that address
the efficacy and safety of these implants. The report on 6 cases did not
indicate efficacy.58

_Non-thermal modalities_

__

Several alternatives to percutaneous radiofrequency denervation have been
proposed, including pulsed radiofrequency, cryoablation, laser ablation, and
chemical ablation, in which a neurolytic substance (e.g., alcohol, phenol,
glycerol) is injected into the affected nerve root. An alternative method of
denervation using an endoscopic approach (i.e., endoscopic dorsal ramus
rhizotomy) has also been proposed.59 The literature on these modalities is
largely limited to case reports or small series with mixed results.60-63 One
RCT (n=80) comparing pulsed RFA to steroid injections concluded it may be more
effective than steroids.64 A RCT (n=50) compared study of continuous to pulsed
RFA and did not report significant differences.65 Long-term safety and
efficacy data is lacking. The ASA Task Force on Chronic Pain Management and
the ASRA Practice Guidelines for Chronic Pain Management (2010)
Recommendations for Ablative Techniques: The Task Force notes that other
treatment modalities should be attempted before consideration of the use of
ablative techniques.45

Facet joint procedures are a challenging area due to variability in the
literature, lack of consensus among experts, differences in societal
guidelines and a historical pattern that demonstrates high risk for over
utilization. When there is a lack of consensus on best practices, careful
evaluation of the medical literature and utilization of the best available
evidence serves as the basis for our determinations in coverage and
guidelines. This is supplemented with the knowledge shared from our SME panel.

The literature and consensus of the expert panel and societal guidelines agree
that there is no specific history, physical exam findings, or imaging studies
that can diagnose facet joint mediated pain and predict response to treatment.
For this reason, diagnostic facet joint injections are indicated. MBBs are the
preferred technique for these injections, which is validated and supported by
literature as compared to the IA injections, which lack validation, are
technically more difficult, and more painful. There is consensus that all
facet procedures should be performed under image guidance, CT or fluoroscopy,
with a preference for fluoroscopy.

The controversial areas are the number of blocks and the percentage of pain
relief required to consider a block successful. For the diagnostic block, the
pain relief achieved is temporary and used as a predictor of success for
subsequent RFA. The objective is to reduce false-positives that would not be
predictive of success with RFA and avoid false-negative patients who could
benefit but would not be offered treatment. Many studies have used a cut-off
of pain relief greater than 75-80% to consider a diagnostic block as positive.
Ten studies assessing the prevalence of lumbar facet joint pain using a cut-
off value of 80% relief reported with a prevalence rate of 27% to 40% with
false-positive rates of 27% to 47% received a moderate to strong
recommendation from 2020 ASIPP Guidelines.7

The 2020 Consensus Guidelines advocate for using single blocks with 50% for
clinical trials and clinical practice while acknowledging that the existing
evidence does not adequately address the 50-80% group and that this cut-off
was selected to maximize access to care given lack of reliable alternative
treatment options in this population and potential benefit of treatment in
this group. On the contrary, there are studies that show patients with dual
blocks using 80% relief are more likely to show a positive response to RFA.
This aligns with ASIPP and NASS guidelines.1,11 Given the lack of clear
evidence, the consensus among experts and societies is that there is
uncertainty regarding the cut-off values and number of blocks. Most of the
evidence and societal guidance supports the use of a more stringent diagnostic
cut-off. The multi-MAC SME panel was a score of 3.2/5 favoring the dual block
regimen. Once a patient begins treatment, the treatments often continue
without repeat diagnostic studies, so the correct diagnosis initially is
important. The existing evidence is clear there is a high risk of false-
positives with a single block and 50% cut-off and that a dual block and higher
cut-off (75-80%) improves diagnostic accuracy. The evidence also supports that
improved diagnostic accuracy predicts greater improvement with RFA treatments.
While this must be balanced against excluding some patients for treatment who
may potentially benefit, given the lack of supporting literature to define
this population, current evidence supports dual blocks at 75-80% improvement
is more strongly supported than the alternative less stringent approach.

The effectiveness and clinical utility of therapeutic facet blocks is another
controversial area. In this case, we are referring to injections with
corticosteroids as injections as local anesthetic would not be expected to
have any sustained effect. There is support for the use of therapeutic
injections in the form of a systematic review and societal guidelines. Most of
this support is from a single center that utilizes a published, modified
grading criterion they developed. Grading from 1 grading criteria to another
often have similarities but cannot be extrapolated to another so we must
consider each grading criteria individually. There is some additional
literature from other sites and societal support for therapeutic injections
offered by ASA and ASRA. The overwhelming majority of other guidelines and
evidence do not support therapeutic IA injections, and this includes multiple
studies, systematic reviews, and guidelines by 2020 Consensus Guidelines,
NASS, NICE, AHRQ, AANS, and CNS. Their use received a "D" rating from 2020
Consensus Guidelines. The current consensus is that diagnostic injections are
to select patients who may be candidates for RFA, and not for therapeutic
injections. Clinically since the reported efficacy of therapeutic injections
(if a true benefit exists) would be around 3 months compared to 6 months or
longer for RFA, so there is an obvious benefit for selection of RFA as a
treatment over injections. The multi-MAC SME voting was 3.4/5 that subsequent
therapeutic IA or MBB are effective. The evidence does support several special
circumstances when RFA cannot be performed, and therapeutic injections may be
appropriate. Therefore, the policy allows therapeutic injections in
circumstances when RFA is not feasible.  

The goal procedure for facet joint interventions is RFA. The strongest
available data related to facet interventions is to support the use of RFA for
facet joint pain. Still, even that is mixed and lacks a clear consensus on
proper patient selection and effectiveness. A 2015 Cochrane review showed a
moderate benefit for RFA for pain, but lack of benefit for function.46
However, the patient selection used the less stringent criteria of a single
block with a 50% reduction in pain. Other studies have shown this criterion is
associated with a higher false-positive rate and less success with RFA
procedures, so this conclusion may not be represented if the stricter criteria
were used. The FACTS study, an RCT that compared outcomes stratified by
different prognostic values and reported the success rate in those who
underwent RFA in the zero (no block), single and double block groups were 33%,
39%, and 64%, respectively.33 While this served as the basis for recommending
a single block at 50% in the 2020 Consensus Guidelines, it also demonstrates
the improved success rate for the dual block group, which increased to 64%.20
A systematic review that used the GRADE system for rating which is a more
standardized grading system and allows both RCT and observational studies to
be evaluated, concluded the majority of patients were pain free at 6 months
and over a third pain free at 1 year.29 This conclusion was supported by a
2017 meta-analysis.35 The overall societal consensus is in support of the use
of RFA with ASIPP, ASA/ASRA, NICE, 2020 Consensus Guidelines, and AANS/CNS,
all having guidelines that support RFA use. Even the NASS Guidelines that
report insufficient evidence for RFA provided guidelines for use. There remain
concerns as the clinical studies of RFA for chronic low back pain have
significant methodological limitations that can affect the interpretation of
the data. Uncertainties regarding several aspects of RFA for spinal pain,
necessitate additional research. The validation of radiofrequency for chronic
spinal pain management relies upon the resolution of these technical issues,
as well as issues regarding patient selection and long-term efficacy.48 While
the literature is not complete in terms of efficacy and patient selection for
RFA facet procedures, the procedure offers the potential to avoid more
invasive surgery. It may potentially reduce opioid use, justifying maintaining
RFA as an option in the management of back pain in properly selected patients
despite these limitations.

Limitations, such as number of levels and frequency, are challenging as there
is little evidence focusing on these factors. Lack of consensus in the medical
community about frequency of injections has been a challenge.52 Societies have
begun to offer recommendations on frequency. The NASS Coverage Recommendations
recommends dual blocks, does not recommend therapeutic procedures, recommends
limiting RFA to maximum of twice per year and procedures for facet joint cyst
rupture to be repeated not more than once.11 The 2020 Consensus Guidelines
report recommends single diagnostic blocks, does not recommend therapeutic
injections and recommends limiting RFA to no more than 2 times per year.4 The
multi-MAC SME panel also provided input on frequency. The panel voted 1.8/5
that diagnostic injections should be a minimum of 28 days apart and
recommended allowing sooner may be beneficial. The panel voted 3.5/5 that
therapeutic injections should be a minimum of 3 months apart, and during
treatment phase interventional procedures should be repeated only if medically
necessary, and not to exceed 4 times per year was scored as 3.4/5. The panel
voted RFA should be repeated only if medically necessary at a minimum of 6
months apart with a score of 3.9/5. The panel supported allowing 3 levels
(diagnostic or therapeutic) in 1 session with score of 3.8/5; however,
prevalence data demonstrates that 3 diagnostic levels are not routine and
would be under unusual circumstances.

Several alternatives to percutaneous radiofrequency denervation have been
proposed, including pulsed radiofrequency, cryoablation, laser ablation, and
chemical ablation, in which a neurolytic substance (e.g., alcohol, phenol,
glycerol) is injected into the affected nerve root. An alternative method of
denervation using an endoscopic approach (i.e., endoscopic dorsal ramus
rhizotomy) has also been proposed. There is insufficient evidence in the
published medical literature to determine the safety and efficacy of these
emerging alternative modalities or approaches compared to thermal
radiofrequency denervation for the treatment of spinal pain.