2010 May
Efficacy and Safety of Pulsed Radiofrequency Treatment in Chronic Pain Syndromes
Barreto J, Carrington M, Correia-Pinto J, Monteiro P, Oliveira L, Paula Pinto M, Pinto I, Pinto Faria A, Rey-Formoso
J, Silvério T, Teixeira P, Soares J, Valente M
ABSTRACT
BACKGROUND Pulsed radiofrequency
(PRF) is a growing method for treating
chronic pain, defined as an unpleasing
sensory experience associated with actual
or potential tissue damage with duration of
more than six months. AIM Our primary
aim is to systematically review the evidence
about efficacy and safety of pulsed
radiofrequency in patients with chronic pain
syndromes. METHODS We used four
different databases (Pubmed, ISI Web of
Knowledge, SCOPUS and Central) using
the following key words: chronic, pain,
pulsed and radiofrequency, applying no
limits and in all languages. We included all
type of articles (except meta-analyses, case
series, reviews, letters and case reports of
single patients) that mention the methods
and results used to test the effectiveness and
safety of PRF on treatment of a variety of
chronic pain syndromes in humans.
RESULTS Our search of literature for
pulsed radiofrequency yielded 78 citations.
After reviewing the abstracts and excluding
the ones that didn’t match our criteria, we
found 13 relevant articles.
INTRODUCTION
The importance of this treatment consists
on its apparent lack of side effects which is
appealing for those who suffer from chronic
pain which has detrimental effects on
physical and mental health. [1]
Although it presents a growing popularity,
its efficacy and safety still remains a
controversial issue. It is important to notice
that it is not uncommon for therapies with
uncertain efficacies to become established
before reliable experiments. [2]
Thus, our primary aim is to systematically
review the evidence about efficacy and
safety of pulsed radiofrequency in patients
with chronic pain syndromes.
METHODS
Study design
A systematic review and meta-analysis of
primary studies focusing on the efficacy
and safety of pulsed radiofrequency in the
treatment of chronic pain syndromes is
being undertaken. The methodological
approach includes the development of
selection criteria, definition of search
strategies, quality assessment of the studies,
data abstraction and statistical data analysis.
[3]
Chronic pain is an unpleasing sensory
experience associated with actual or
potential tissue damage with duration of
more than six months. It is the most
underestimated
healthcare
problem
impacting quality of life. [1]
Pulsed radiofrequency is a recently
developed treatment modality for pain
syndromes such as chronic pain. It uses
brief pulses of high voltage to produce
controlled tissue destruction, reducing pain
by modulating its transmission.
Search strategy
The MEDLINE database, ISI Web of
Knowledge, SCOPUS and the Cochrane
Central Register of Controlled Trials
(CENTRAL)
were
searched
for
identification of primary studies focusing
on efficacy and safety of pulsed
radiofrequency in the treatment of chronic
pain syndromes.
The queries used were: “pulsed[All Fields]
AND radiofrequency[All Fields] AND
(("pain"[MeSH Terms] OR "pain"[All
Fields]) AND chronic[All Fields])” for
MEDLINE, “TS=(Radiofrequency SAME
pulsed) AND TS=pain AND TS=chronic”
for ISI Web of knowledge, “TITLE-ABSKEY(radiofrequency) AND TITLE-ABSKEY(pulsed)
AND
TITLE-ABSKEY(pain)
AND
TITLE-ABSKEY(chronic)” for SCOPUS and “
#1
MeSH descriptor Pain explode all trees, #2
(Chronic): ti, ab, kw, #3 (Radiofrequency
Near Pulsed): ti, ab, kw” for CENTRAL.
Selection criteria and selection process
Articles identified through the database
searches were included in this review if the
purpose of it was to study efficacy and
safety of pulsed radiofrequency as a
treatment for chronic pain syndromes.
Articles that have, at least, two comparative
groups - a group submitted to pulsed
radiofrequency and a control group
(experimental and observational studies –
clinical trials, cohort studies and casecontrol studies) were included in the present
review.
Meta-analyses, case series, reviews, letters
and case reports of single patients were
excluded. Studies which were not
conducted in humans were excluded as
well. Studies were not excluded on the
basis of quality assessment or language of
publication.
The studies selection process includes two
phases. In the first phase of selection, the
titles and abstracts of the retrieved studies
were screened for relevance by at least two
reviewers. In the second phase, two
reviewers are independently analyzing the
full-papers of articles identified as
potentially relevant. Selection criteria were
applied; exclusions were decided and
recorded and disagreements were settled by
a third reviewer.
Study quality
abstraction
assessment
and
data
The quality assessment of the included
articles will be performed by using criteria
based on CONSORT Statement (for clinical
trials) [4] or STROBE Statement (for
observational studies). [5]
Quality of articles described as randomized
controlled trials (RCT’s) will be scored by
using the Jadad Scale, a three item quality
scale [6]. The scale takes into account
randomization,
double-blinding
and
reporting of drop-outs and withdrawals.
For observational studies we will use a
selection of methodological criteria based
on STROBE checklist.[7]
Statistical analysis
Summary
presentation
of
general
characteristics of included studies was
performed applying appropriate descriptive
statistics. For this descriptive analysis the
statistical analysis software PASW 18th
version was used. [8]
Pooled analysis of efficacy and safety
measures will be performed with
appropriate meta-analysis methods if the
available primary studies data allows it. We
will calculate pooled efficacy and safety
measures, present forest plots, perform
heterogeneity analysis, present subgroup
analysis and test for publication bias. The
software RevMan version 5.0 will be used
for this pooled analysis. [9]
RESULTS
The following are the results we have at this
point of our work. These are not the final
results, but the results of our search for
primary studies
selection.
and
their
posterior
Search for primary studies
In our search we identified a total of
seventy-eight articles. The MEDLINE
search identified forty-eight articles. Of
those forty-eight articles, four were
exclusive of the MEDLINE data base.
Sixty-five articles were found through
SCOPUS, including forty-four that were
initially identified through the MEDLINE
search. Of the sixty-five articles identified
in SCOPUS data base, twenty were
exclusive. The ISI Web of Knowledge
search yielded thirty-two articles, of which
twenty-three were previously identified.
The ISI Web of Knowledge had eight
exclusive articles. Three articles were found
through CENTRAL and they had already
been identified, so there were no exclusive
articles in CENTRAL data base.
In 2000 was published two of the selected
articles (2,6%). In 2002 were published
three of the selected articles (3,8%). In
2003 were published eight of the selected
articles (10,2%). In 2004 were published six
of the selected articles (7,7%). In 2005 were
published eight of the selected articles
(10,2%). In 2006 were published eleven of
the selected articles (14,2%). In 2007 were
published fourteen of the selected articles
(17,9%). In 2008 were published thirteen of
the selected articles (16,6%). In 2009 were
published eleven of the selected articles
(14,2%). In 2010 were published two of the
selected articles (2,6%) as Figure 1 shows.
16
14
12
10
8
6
4
2
0
2000
2002
2004
2006
2008
Figure 1 - Publication year of the identified studies
2010
The top three journals who contributed with
more articles in our search were “Pain
Practice: The Official Journal of World
Institute of Pain” with thirteen articles
(16,6%), the “Pain Physician” with nine
articles (11,5%) and the “Pain Medicine
(Malden, Mass.)” with seven articles
(8,9%).
Studies Selection
In the selection process, were excluded
sixty-five studies. Two articles (3,1%) were
excluded because their theme did not match
the expected. One (1,6%) article was
excluded because the treatment was not
used to treat chronic pain. Fifty-nine
articles (90,7%) were excluded because the
type of article was not the desired. Three
articles (4,6%) were excluded because the
study was not conducted in humans.
All titles and abstracts were studied by two
reviewers and in the inclusion/exclusion
argument there were no disagreements (0%)
and 78 agreements (100%). In 74 cases
(94,8%) there were agreements concerning
the reason of exclusion. In 4 cases (5,2%)
there were disagreements concerning the
reason of exclusion and was needed a third
reviewer.
The MEDLINE search identified forty-eight
articles, of which nine met the inclusion
criteria. Sixty-five articles were found
through SCOPUS, including forty-four that
were initially identified through the
MEDLINE search. Three of the remaining
articles met the inclusion criteria. The ISI
Web of Knowledge search yielded thirtytwo articles, of which twenty-three were
previously identified. Two of the remaining
articles were included. Three articles were
found through CENTRAL and they had
already been identified. At the end, seventyeight articles were found and thirteen were
included in this systematic review.
Characteristics of
included studies
the
author’s last name, journal in which were
published and their publication year.
provisionally
These studies were published between 2003
and 2010. The Table 1 shows their title, first
Table 1 - Characteristics of the provisionally included studies
Title
Percutaneous pulsed radiofrequency applied to the L2 dorsal root ganglion for treatment of chronic lowback pain: 3-year experience
Last name of
first author
Tsou
Journal
Publication
year
Database
Journal of Neurosurgery:
Spine
2010
PubMed, SCOPUS, ISI
Web
Pulsed radiofrequency on L2 dorsal root ganglion as
a therapeutic method for lumbar discogenic pain
Assis
Coluna/Columna
2009
SCOPUS
Response to pulsed and continuous radiofrequency
lesioning of the dorsal root ganglion and segmental
nerves in patients with chronic lumbar radicular pain
Simopoulos
Pain Physycian
2008
PubMed, SCOPUS, ISI
Web, CENTRAL
A comparison of conventional and pulsed
radiofrequency denervation in the treatment of
chronic facet joint pain
Tekin
Clinical Journal of Pain
2007
PubMed, SCOPUS, ISI
Web, CENTRAL
Pulsed radiofrequency adjacent to the cervical dorsal
root ganglion in chronic cervical radicular pain: a
double blind sham controlled randomized clinical
trial
Van Zundert
Pain
2007
PubMed, SCOPUS, ISI
Web, CENTRAL
Contemporary role of radiofrequency treatment for
intractable pain syndromes
Park
European Congress of
Neurosurgery
2007
ISI Web
Pulsed radiofrequency treatment of the lumbar
medial branch for facet pain: a retrospective analysis
Lindner
Pain Medicine
2006
PubMed, SCOPUS, ISI
Web
Pulsed radiofrequency of the dorsal root ganglia is
superior to pharmacotherapy or pulsed
radiofrequency of the intercostal nerves in the
treatment of chronic postsurgical thoracic pain
Cohen
Pain Physician
2006
PubMed, SCOPUS
Radiofrequency in the treatment of chronic cervical
spine pathology. Retrospective study
Abejon
Revista de la Sociedad
Española del Dolor
2006
SCOPUS
Bayer
Pain Practice
2005
PubMed, SCOPUS
Percutaneous pulsed radiofrequency treatment of the
cervical dorsal root ganglion in the treatment of
chronic cervical pain syndromes: A clinical audit
Van Zundert
Neuromodulation
2003
SCOPUS, ISI Web
Pulsed mode radiofrequency lesioning of the
suprascapular nerve for the treatment of chronic
shoulder pain
Shah
Pain Physician
2003
PubMed, SCOPUS, ISI
Web
Pulsed radiofrequency application in treatment of
chronic zygapophyseal joint pain
Mikeladze
Spine Journal
2003
PubMed, SCOPUS
Sphenopalatine ganglion pulsed radiofrequency
treatment in 30 patients suffering from chronic face
and head pain
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