Appendix II - Description of the selected studies
The study by Civelek et al (2012)10 compared the clinical effectiveness of facet joint
injections (FJI) and facet joint radiofrequency (FJRF) denervation. Inclusion criteria were
chronic and debilitating low back pain (LBP), a diagnosis of lumbar facet syndrome
including radiological evaluation, and no response to conservative treatment for at least 6
weeks including pain medication and physical therapy. Patients were randomized in to
groups, but he stated that pain relief after FJI was an inclusion criteria for FJRF, implying
that these patients might have been selected with different criteria. Patients with radicular
pain, neurogenic claudication, neurological deficits and uncontrolled medical illness were
excluded. Informed consent and IRB approval was obtained. In all, 100 patients were
randomized from multiple centers in two intervention groups of 50 patients each. Outcome
was measured after 1 and 6 months and after 1 and 2 years by telephone interviews using
the Visual Numeric Pain Scale (VNS), North American Spine Society (NASS) patient
satisfaction questionnaire and Euro-Qol in five dimensions (EQ-5D) by blinded raters.
Response ("successful treatment") was determined by a 50% or more reduction in the
VNS and a NASS score of 1 and 2 and EQ-5D less than 9. Complications related were
small superficial burns, transient burning-like sensation and increase in low back pain in
two patients from the RF group.
Duger et al (2012)11 aimed to compare the effects of radiofrequency, local anesthetic and
steroid injection and combination of them for facet syndrome low back pain. Inclusion
criteria were age between 18 and 60 years, symptoms of facet joint pain longer than 6
months and absence of radicular signs. Exclusion criteria included major depression or
other uncontrolled psychiatric disorders, opioid treatment and prior surgery at the same
site. Informed consent and IRB approval was obtained. All 120 patients were randomized
in three groups and assessed regarding VAS, activity and satisfaction scores, with 12
month maximum follow-up. No complications were related.
The oldest study included was published by Gallagher et al (1994) 12. Inclusion criteria
were back pain with facet joint signs for at least 3 months and age 25 to 55 years.
Previous back surgery, major mental illness, radicular signs, pending compensation claims
and general ill health were exclusion criteria. Local ethics committee approval and
informed consent were obtained. Patients who gained no relief from anesthetic facet joint
injection were excluded at this point. Patients were randomized to placebo or
radiofrequency denervation. VAS and McGill scale scores were recorded up to 6 months.
Functional outcome and quality of life were not addressed. No adverse effects were
reported.
A randomized study by Lakemeier et al (2013)13 compared the effectiveness of intraarticular facet joint steroid injections and radiofrequency denervation. Facet joint related
pain for more than 24 months, magnetic resonance imaging findings showing
abnormalities at facet joints, positive response to test injection with anesthetics and age
over 18 and were inclusion criteria. Exclusion criteria included spinal stenosis, fractures,
instabilities, radicular signs and psychiatric disorders. Ethics committee and informed
consent were obtained. The primary end point was Roland-Morris Questionnaire.
Secondary end points were visual analog scale and Oswestry Disability Index. Outcome
assessments were performed up to 6 months. No major adverse effects were reported.
Another study was conducted by Leclaire et al (2001) 14 in which 70 patients between 18
and 65 years of age with low back pain lasting for at least 3 months and good response to
intra-articular facet injections were randomized to either FJRF denervation (n=36) or a
sham procedure (n=34). Patients with general medical conditions, sciatic pain with
neurological deficit or previous low back surgery were excluded. Outcome was measured
using the VNS, Oswestry and Roland-Morris scales, and functional disabilities at 4 and 12
weeks of follow-up by blinded raters. IRB approval and patient consent was obtained.
Response criteria were not defined, and statistical analyses aimed at obtaining treatment
effect measures. Of the 16 nonworking patients, eight patients in each group returned to
work after 12 weeks. No complications were reported.
Nath et al (2008)15 evaluated 40 patients randomized either to FJRF denervation (n=20) or
a sham procedure (n=20). All patients were adults with at least 2 years of continuous low
back pain, not responding to conventional treatment, and having three separate positive
facet blocks. Patients with general medical conditions, indication for surgical treatment or
patients that lived too far away were excluded. All procedures were performed by the
same operator and outcome was measured by VAS and self-rating 6-point scales that
measured relief of pain and perception of improvement, among other measures. A
response criterion was not defined, and analyses were made comparing groups at the 6
month follow-up point. No complications were reported.
Tekin et al (2007)16 conducted double-blind, randomized, sham controlled study comparing
conventional with pulsed FJRF denervation. IRB approval and patient consent was
obtained. Patients included were of at least 17 years of age, had continuous low back pain
for at least 6 months with a positive response to a diagnostic block without indication for
surgery, had no radicular pain or neurological deficit and were unresponsive for
conventional treatment. Exclusion criteria included malignancy and psychiatric disorders.
Twenty patients were allocated in each treatment group and a sham control group with
follow-up measures at 6 hours, 6 months and 1 year in which VAS and the Oswestry
Disability Index were obtained by blinded raters. There were no complications related.
In the study by van Kleef et al (1999)17 31 patients with a history of at least 1 year of low
back pain and a positive response to nerve blockade were randomized to assess the
clinical efficacy of FJRF denervation in an active (n=15) and sham group (n=16). Patients
with prior back surgery, malignancy, infection, extensive spondylosis, stenosis, disk
herniation, trauma and diabetes mellitus were excluded. Patients and investigators were
blinded and IRB approval and informed consent was obtained. All patients were between
20 and 60 years and had an initial VAS of more than four. Patients with previous surgery,
a known cause of low back pain and general medical conditions were excluded. Outcome
measures were obtained using VAS, Oswestry disability scale, Wadell impairment scale
and COOP/WONCA quality of life scale, among other measures. Assessments were
conducted before and 8 weeks, 3, 6, and 12 months after the procedure. A response
criterion was defined as a 2-point reduction or more on the VAS and at least a 50% pain
reduction on global perceived effect. No complications were reported.
In the study by van Wijk et al (2005)18 81 patients from multiple centers were randomized
in a FJRF denervation group (n=40) and a sham procedure control group (n=41) under a
double-blind condition. IRB and informed consent was obtained. Inclusion criteria were low
back pain for more than 6 months and a 50% or more reduction in VAS after a diagnostic
block. Exclusion criteria were general medical conditions, prior FJRF treatment, major
psychiatric disorders and radicular syndrome. Primary outcome was determined with a
combined outcome measure comprising VNS, physical activities, and analgesic intake,
rated by blinded and independent investigators at three months intervals, with the last
follow-up visit at 12 months. Treatment related costs were also determined for the first
three months. Reported complications included treatment-related pain in both groups
(69.2% in RF group, 46.2% in sham group), one patient with evident dysaesthesia /
allodynia in the RF group and two patients with minor motor function loss in each group.
Characteristics of excluded studies
The study by Buijs et al (2004)19 was excluded since only neurophysiological data was
obtained to analyze lesion size reproducibility, with no information regarding clinical
outcomes.
Cohen et al (2010)20 and Kroll et al (2008)21 were excluded because their study design did
not include a sham control group. In addition, Cohen et al (2010) assessed the
effectiveness of diagnostic block before radiofrequency denervation.
The study by Oh et al (2004)22 was excluded from our investigation as it focused on low
back pain of discogenic origin.
The study by Tejeda-Barreras et al (2010)23 was excluded as there was no description by
the authors of IRB approval or patients providing informed consent. The study also lacked
randomization procedures, definition of conventional treatment refractoriness, and clear
definition of response criteria.
Finally, the study by Young et al (2013)24 was excluded because it focused only on the
treatment of recurrent pain after successful FJRD.
Ongoing studies
The search retrieved one ongoing study: “Percutaneous RadioFrequency treatment for
facet joint pain”. The contact author is Dr. Cornelius van Tilburg. Primary outcome
measure is pain and secondary outcome measures are chronic pain acceptance, disability,
generic health status, kinesiophobia, coping, and costs. There is currently no data
available, and therefore this study was not included in our analysis.