Analgesic effect of whole body cryotherapy in patients with trapezius myofascial pain syndrome: A longitudinal, non-blinded, experimental study

Abstract

Objective
To determine the analgesic effect of whole body cryotherapy (WBC) in patients with trapezius myofascial pain syndrome.

Methods
Twenty patients from an outpatient rehabilitation clinic were recruited. Patients were required to have clinical data for their diagnosis of myofascial pain syndrome in the trapezius. Twenty WBC sessions (−160 °C) were prescribed at four sessions per week for five weeks. A visual analog scale for pain (VAS) and algometry at trigger points (TPs) were applied before and after each session to measure the Pressure Pain Threshold (PPT). Six blood samples per patient were obtained during the study to measure the serum concentration of pro-inflammatory and anti-inflammatory cytokines.

Results
A significant decrease in pain immediately after WBC was found from session 1 (p < 0.001) onwards. Furthermore, a significant difference was observed in VAS at baseline compared to the value before each cryotherapy session starting from session 6 (p < 0.001). Significant differences were found in algometry at each session (p < 0.001) and when comparing the initial and pre-session values starting from session 6 (p < 0.001). No significant differences were found in the concentrations of inflammatory or anti-inflammatory factors throughout the study (p > 0.05).

Conclusions
WBC is useful as an analgesic treatment for myofascial pain syndrome in trapezius.’

Full text

Medicina
Universitaria.
2017;19(76):115---122
www.elsevier.es/rmuanl
ORIGINAL
ARTICLE
Analgesic
effect
of
whole
body
cryotherapy
in
patients
with
trapezius
myofascial
pain
syndrome:
A
longitudinal,
non-blinded,
experimental
study
Ó.A.
García-Espinoza∗,
Ó.
Salas-Fraire,
P.P.
Flores-Garza,
K.
Salas-Longoria,
J.A.
Valadez-Lira
Department
of
Sports
Medicine
and
Rehabilitation
of
the
‘‘Dr.
José
Eleuterio
González’’
University
Hospital
of
the
Autonomous
University
of
Nuevo
León,
Monterrey,
Mexico
Received
3
March
2017;
accepted
10
July
2017
Available
online
14
November
2017
KEYWORDS
Whole
body
cryotherapy;
Myofascial
pain
syndrome;
Analgesic
effect
Abstract
Objective:
To
determine
the
analgesic
effect
of
whole
body
cryotherapy
(WBC)
in
patients
with
trapezius
myofascial
pain
syndrome.
Methods:
Twenty
patients
from
an
outpatient
rehabilitation
clinic
were
recruited.
Patients
were
required
to
have
clinical
data
for
their
diagnosis
of
myofascial
pain
syndrome
in
the
trapezius.
Twenty
WBC
sessions
(−160 ◦C)
were
prescribed
at
four
sessions
per
week
for
five
weeks.
A
visual
analog
scale
for
pain
(VAS)
and
algometry
at
trigger
points
(TPs)
were
applied
before
and
after
each
session
to
measure
the
Pressure
Pain
Threshold
(PPT).
Six
blood
samples
per
patient
were
obtained
during
the
study
to
measure
the
serum
concentration
of
pro-inflammatory
and
anti-inflammatory
cytokines.
Results:
A
significant
decrease
in
pain
immediately
after
WBC
was
found
from
session
1
(p
<
0.001)
onwards.
Furthermore,
a
significant
difference
was
observed
in
VAS
at
baseline
com-
pared
to
the
value
before
each
cryotherapy
session
starting
from
session
6
(p
<
0.001).
Significant
differences
were
found
in
algometry
at
each
session
(p
<
0.001)
and
when
comparing
the
ini-
tial
and
pre-session
values
starting
from
session
6
(p
<
0.001).
No
significant
differences
were
found
in
the
concentrations
of
inflammatory
or
anti-inflammatory
factors
throughout
the
study
(p
>
0.05).
Conclusions:
WBC
is
useful
as
an
analgesic
treatment
for
myofascial
pain
syndrome
in
trapez-
ius.’
©
2017
Universidad
Aut´
onoma
de
Nuevo
Le´
on.
Published
by
Masson
Doyma
M´
exico
S.A.
This
is
an
open
access
article
under
the
CC
BY-NC-ND
license
(http://creativecommons.org/licenses/
by-nc-nd/4.0/).
∗Corresponding
author
at:
Departamento
de
Medicina
del
Deporte
y
Rehabilitación,
Hospital
Universitario
‘‘Dr.
José
Eleuterio
González’’,
Universidad
Autónoma
de
Nuevo
León,
Ave.
Gonzalitos,
Colonia
Mitras
Centro,
C.P.
64460
Monterrey,
Nuevo
León,
Mexico.
Tel.:
+52
81
83294207.
E-mail
address:
dr.garciaoscar@gmail.com
(Ó.A.
García-Espinoza).
http://dx.doi.org/10.1016/j.rmu.2017.07.004
1665-5796/©
2017
Universidad
Aut´
onoma
de
Nuevo
Le´
on.
Published
by
Masson
Doyma
M´
exico
S.A.
This
is
an
open
access
article
under
the
CC
BY-NC-ND
license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).

116
Ó.A.
García-Espinoza
et
al.
Introduction
Musculoskeletal
processes
are
the
most
common
cause
of
both
acute
and
chronic
pain,
as
well
as
temporary
or
perma-
nent
disability.1It
is
estimated
that
the
global
prevalence
of
these
diseases
ranges
from
13.5
to
47%.
In
Mexico,
the
preva-
lence
of
musculoskeletal
pain
is
approximately
20%
and
is
consistently
more
prevalent
in
women
and
urban
areas.2It
is
estimated
that
one-third
of
patients
with
musculoskele-
tal
pain
meet
the
diagnostic
criteria
for
myofascial
pain
syndrome.3,4 Myofascial
pain
syndrome
affects
up
to
85%
of
the
population
at
some
point
in
their
lives.5
Myofascial
pain
syndrome
(MPS)
refers
to
soft
tissue
pain
resulting
from
irritation
of
local
points
within
the
skeletal
muscle
and
myotendinous
junctions.
These
local
points
are
known
as
trigger
points.6These
trigger
points
(TPs)
have
been
described
as
hyperirritable
sites
located
in
a
taut,
muscular
band,
which
are
felt
as
small
painful
nodules
that
produce
nociceptive
pain
caused
by
compression.3
It
has
been
postulated
that
TPs
are
the
result
of
acute
muscle
injury
due
to
overuse
or
repetitive
activity.
When
TPs
persist
for
more
than
three
weeks,
the
diagnosis
of
MPS
is
made.7
Physical
examination
and
the
clinical
data
thus
found
are
of
vital
importance
for
the
diagnosis
of
MPS.
When
MPS
is
sus-
pected,
the
presence
of
a
well-defined
trigger
point
within
a
tight
muscle
band
that
causes
pain
when
firm
pressure
is
applied
for
5
s
and
does
not
follow
established
nerve
pat-
terns
can
be
suggestive
of
the
disease.
This
pain
should
be
reproducible
with
each
compression
of
approximately
3
kg/cm2per
second
or
less.6During
the
physical
exami-
nation,
there
is
sometimes
an
obvious
response
of
muscle
twitches
and
a
perception
of
weakness
by
the
patient.8
According
to
the
symptomatology,
regardless
of
the
clini-
cal
findings,
TPs
can
be
divided
into
active
and
latent.6It
is
important
to
consider
fibromyalgia,
bursitis,
tendinosis,
fasciitis,
and
disorders
of
joint
hypermobility
as
differential
diagnoses
of
MPS.6,9,10
MPS
is
a
pathology
that,
while
not
fatal,
represents
a
significant
reduction
in
quality
of
life
and
an
important
cause
of
absence
from
work,
generating
an
enormous
cost
for
its
treatment
in
health
systems.11
Despite
its
high
incidence,
there
is
no
specific
treatment
for
the
disease.
Several
conservative
treatments
have
been
described,
among
them
analgesic
and
anti-inflammatory
drugs,
and
in
recent
years,
acupuncture,
dry
needle
therapy,
and
botulinum
toxin
application.3,4,12,13 Physical
rehabili-
tation
has
been
shown
to
have
significant
value
in
the
management
of
this
disease
and,
due
to
its
analgesic
effect
in
various
musculoskeletal
diseases,
cryotherapy
is
one
of
the
methods
frequently
used.14
The
effects
of
cryotherapy
consist
of
the
provocation
of
several
physiological
effects:
vasoconstriction,
decreased
edema,
and
decreased
spasticity.
Its
direct
analgesic
effect
is
to
reduce
nociceptive
conduction
velocity
in
peripheral
nerves.14---17
There
are
many
different
methods
for
applying
cryother-
apy.
One
of
these
methods
is
whole
body
cryotherapy,
which,
in
addition
to
having
a
local
effect,
provides
a
systemic
effect
by
modifying
the
levels
of
pro-
and
anti-inflammatory
markers.18
Whole-body
cryotherapy
(WBC)
or
total
body
cryotherapy
consists
of
exposing
the
body
to
cold
air
at
temperatures
below
−110 ◦C
in
a
chamber
that
controls
the
temperature.
This
type
of
therapy
has
been
applied
in
several
pathologies
to
relieve
pain
and
inflammation.19
The
anti-inflammatory
effect
observed
in
subjects
after
treatment
with
whole-body
cryotherapy
has
been
an
increase
in
anti-inflammatory
cytokines
(IL-10)
and
a
decrease
in
proinflammatory
cytokines
(IL-2,
IL-8)
and
prostaglandin
E2.20
Recent
studies
suggest
that
WBC
may
be
effective
in
inflammatory
processes
in
patients
with
some
rheumatic
dis-
eases
such
as
rheumatoid
arthritis,
ankylosing
spondylitis,
osteoarthrosis,
and
fibromyalgia.15 Despite
this
recent
intro-
duction
of
WBC
to
the
field
of
treatment
of
rheumatological
diseases,
there
is
no
evidence
of
its
use
in
MPS7,13,21 and
therefore
it
is
important
to
continue
searching
for
new
ther-
apeutic
methods
that
could
be
more
successful
than
those
already
known.
The
aim
of
this
study
was
to
demonstrate
the
analgesic
effect
of
total
body
cryotherapy
in
patients
with
myofascial
pain
syndrome
of
the
trapezius
muscle.
Material
and
methods
Patient
selection
Patients
of
the
Sports
Medicine
and
Rehabilitation
Depart-
ment
of
a
third
level
hospital
in
northeastern
México
with
a
clinical
diagnosis
of
myofascial
syndrome
were
recruited.
These
patients
were
chosen
based
on
their
willingness
to
participate
in
the
study
regardless
of
whether
or
not
they
had
undergone
another
treatment.
The
trial
was
conducted
between
February
and
July
of
2016.
A
sample
of
20
subjects
was
calculated
using
a
hypothesis
test
formula
and
a
differ-
ence
of
two
means,
or
with
the
proportion
of
a
reference
value
considering
a
z␣
value
of
1.96
with
a
level
of
signifi-
cance
of
95%
for
a
queue,
and
a
z␤
value
of
1.28
with
a
power
of
90%,
with
a
difference
from
the
initial
visual
analog
scale
(VAS)
of
at
least
3
points.
Patients
of
both
genders
aged
18---60
years,
with
a
clin-
ical
diagnosis
of
myofascial
pain
syndrome
and
with
a
pain
equivalent
to
3
or
more
points
on
the
VAS
and
who
pro-
vided
signed
informed
consent
were
included.
During
this
trial,
other
analgesic
measures
such
as
NSAIDs,
physical
ther-
apy,
and/or
other
drugs
were
suspended.
Pregnant
women
and
individuals
with
heart
diseases,
respiratory
diseases,
cancer,
sensitivity
alterations,
claustrophobia,
poorly
con-
trolled
hypertension,
mental
disorders
and
skin
wounds,
as
well
as
those
intolerant
to
cold
or
who
had
experienced
adverse
reactions
to
cold
were
excluded.
Patients
who
did
not
comply
with
the
total
number
of
sessions
(n
=
1)
were
eliminated.
Study
design
This
study
was
a
longitudinal,
prospective,
experimen-
tal,
and
non-blinded,
that
was
approved
by
the
Ethics
Committee
of
a
third-level
hospital
in
northeastern
Méx-
ico.
Informed
consent
was
obtained
from
patients
after
a

Cryotherapy
and
myofascial
pain
syndrome
117
verbal
explanation
of
the
procedure,
clarification
of
ques-
tions,
and
the
signing
of
the
document.
Measurements
Each
participant
was
examined
by
the
only
resident
physi-
cian
in
the
specialty
of
sports
medicine
and
rehabilitation
to
assess
the
presence
of
a
myofascial
trigger
point
in
the
trapezius
muscle.
The
following
diagnostic
criteria
were
used:
the
presence
of
a
palpable
band,
a
sensitive
point,
and
the
recognition
of
pain
referred
to
the
neck
or
head.
An
analog
pressure
algometer,
the
Wagner
Pain
TestTM
Model
FPK
10
(Wagner
Instruments,
Greenwich,
CT)
was
used
for
measuring
the
pressure
pain
threshold
(PPT),
which
is
defined
as
the
minimum
amount
of
pressure
required
to
produce
a
sense
of
discomfort
or
pain
at
the
point
being
measured.
A
pain
evaluation
was
performed
using
a
VAS
before
and
after
each
session.
Six
blood
samples
per
patient
were
obtained
during
the
study
to
measure
the
serum
concentration
of
pro-
inflammatory
and
anti-inflammatory
cytokines.
These
were
drawn
at
the
beginning
of
the
protocol
and
after
sessions
4,
8,
12,
16
and
20.
IL-1␤,
IL-6,
IL-8,
IL-10,
PCR,
CPK
and
cortisol
were
evaluated
in
each
session.
A
plate
reader
(Multi-Mode
Synergy
2;
Biotec,
USA)
was
used
for
the
CPK
and
cortisol
determinations,
and
a
flow
cytometer
(BD
AccuriTM
C6;
BD
Biosciences,
USA)
was
used
for
cytokine
analysis.
Whole
body
cryotherapy
sessions
We
used
the
CRYO-B
Chillout
Elite
booth.
We
chose
a
total
20
session
treatment
distributed
by
4
sessions
per
week
as
rec-
ommended
by
the
Cryo-B
manufacturers
and
other
studies.19
Process
After
locating
the
trigger
point,
the
algometer
was
placed
on
it
perpendicular
to
the
muscular
plane
of
the
trapez-
ium.
Gradually,
the
pressure
on
the
trigger
point
increased
at
a
rate
of
1
kg/cm2/s.
The
value
indicated
on
the
algome-
ter
was
recorded
at
the
time
the
subject
reported
pain.
An
evaluation
of
vital
signs
(heart
rate
and
blood
pressure)
was
performed
before
and
after
each
cryotherapy
session.
Patients
underwent
20
full-body
cryotherapy
sessions
at
an
average
temperature
of
−160 ◦C
for
3
min
in
a
liquid
nitrogen-cooled
CRYO-B
booth.
The
sessions
were
dis-
tributed
in
4
sessions
per
week
over
five
weeks.
All
subjects
were
instructed
in
the
following
safety
measures:
the
use
of
gloves,
dry
socks
and
shoes
inside
the
cryotherapy
booth;
arm
and
leg
movement
during
the
session;
and
avoiding
hold-
ing
his/her
breath
with
the
intention
of
reducing
the
risk
of
adverse
effects.
Data
analysis
We
used
SPSS
version
20
(SPSS,
Inc.,
Armon,
NY)
to
perform
hypothesis
testing
and
the
difference
of
two
means.
Descrip-
tive
statistics
were
obtained
and
a
hypothesis
test
formula
was
used
with
the
difference
of
two
means
as
a
reference
value
for
the
evaluation
of
VAS
and
PPT.
For
the
analysis
of
laboratory
results,
we
used
the
Kolmogorov
Smirnov
test
to
determine
the
distribution
of
the
data,
the
Student’s
t-
test
for
tests
related
to
parametric
distribution
(IL-1␤,
IL-10,
TNF,
CPK,
and
Cortisol)
and
the
Wilcoxon
rank-sum
test
for
nonparametric
variables
(IL-6
and
IL-8).
Results
Twenty
subjects
were
included
in
the
study,
of
which
15
were
women,
and
5
were
men.
The
mean
age
of
the
patients
was
40.86
±
11.04
years,
with
an
age
range
of
23---56
years.
The
mean
VAS
of
pain
at
the
start
of
the
study
was
7.00
±
1.37
points
and
was
2.25
±
2.09
points
at
the
end
of
the
study.
A
statistically
significant
reduction
in
pain
imme-
diately
after
application
of
full-body
cryotherapy
was
found
from
session
1
(p
<
0.001).
(Table
1)
Also,
a
significant
differ-
ence
was
observed
in
the
value
of
VAS
at
baseline
compared
with
the
previous
value
at
each
cryotherapy
session
starting
from
the
6th
session
(p
<
0.001)
(Table
2).
As
for
the
PPT
measured
by
the
pressure
algometer,
a
significant
difference
was
also
found.
The
mean
algometry
value
at
the
beginning
of
the
study
was
1.44
±
0.35
kg/cm2/s
of
pressure,
and
at
the
end
it
was
2.49
±
0.34
kg/cm2/s
of
pressure,
with
significant
differences
in
algometry
values
at
each
full-body
cryotherapy
session
(p
=
<
0.001)
(Table
3),
as
well
as
in
comparisons
made
between
the
initial
and
pre-
session
values
starting
from
session
6
(p
<
0.001)
(Table
4).
Initial
and
follow-up
results
at
the
4th,
8th,
12th,
16th,
and
20th
sessions
of
the
measured
substances
(Cortisol,
ILs)
are
shown
in
Tables
5
and
6.
Tables
7
and
8
show
the
changes
in
the
follow-up
sessions
compared
to
the
initial
measure-
ment.
There
is
a
tendency
toward
the
relation
of
exposure
of
WBC
and
elevation
of
some
of
the
quantified
substances
(IL-
10,
Cortisol),
as
well
as
the
decrease
of
others,
such
as
CPK;
However,
this
association
was
not
statistically
significant
(p
>
0.05).
No
adverse
effects
occurred
during
the
study.
Discussion
As
previously
mentioned,
there
is
no
specific
treatment
for
myofascial
pain
syndrome.
This
is
probably
due
to
lim-
ited
evidence
of
the
efficacy
of
procedures
used
to
treat
it.
This
forces
researchers
to
continue
the
search
for
the
perfect
treatment.
Although
there
are
several
studies
on
the
treatment
of
myofascial
syndrome
with
pharmacologi-
cal
therapy,
physical
therapy,
botulinum
toxin
application
and
dry
needle
therapy,
there
are
no
studies
evaluating
the
efficacy
of
whole
body
cryotherapy
to
treat
this
condi-
tion.
Algafly
and
George,
and
Bleakley
et
al.
described
the
effects
of
cryotherapy
on
nerve
conduction,
pain
threshold,
and
pain
tolerance,
finding
that
such
effects
were
main-
tained
during
short-term
exposure
to
cold
through
full-body
cryotherapy.14,19
In
this
study,
the
application
of
whole
body
cryotherapy
produced
a
decrease
in
perceived
pain,
measured
with
VAS.
The
analgesic
effect
was
observed
in
each
of
the
20
ses-
sions
of
cryotherapy,
becoming
more
evident
starting
from
the
sixth
session,
where
a
cumulative
analgesic
effect
is

118
Ó.A.
García-Espinoza
et
al.
Table
1
Difference
in
VAS
score
per
session.
Session
Pre-mean
Post-mean
Mean
difference
SEM
95%
CI
p
value
1
7.000
4.476
2.524
±
1.90
0.414
3.436---1.707
0.000
2
5.650
3.571
2.079
±
1.30
0.285
2.737---1.549
0.000
3
5.700
4.000
1.700
±
1.15
0.250
2.236---1.192
0.000
4
5.150
3.690
1.460
±
1.28
0.280
2.037---0.868
0.000
5
5.200
3.925
1.275
±
0.99
0.222
1.740---0.810
0.000
6
4.450
3.275
1.175
±
1.13
0.255
1.708---0.642
0.000
7
4.875
3.275
1.600
±
1.23
0.275
2.176---1.024
0.000
8
4.150
2.650
1.500
±
1.19
0.267
2.058---0.942
0.000
9
4.350 2.925 1.425
±
0.85 0.189
1.821---1.029
0.000
10
3.950 2.700 1.250
±
0.97 0.216 1.702---0.798
0.000
11
3.850 2.700 1.150
±
0.99 0.221 1.612---0.688 0.000
12
3.600
2.400
1.200
±
1.06
0.236
1.694---0.706
0.000
13
3.650
2.475
1.175
±
1.09
0.244
1.686---0.664
0.000
14
3.600
2.450
1.150
±
0.81
0.182
1.530---0.770
0.000
15
3.550
2.450
1.100
±
1.02
0.228
1.578---0.622
0.000
16
3.200
2.150
1.050
±
0.89
0.198
1.465---0.635
0.000
17
3.250
2.100
1.150
±
1.04
0.233
1.637---0.663
0.000
18
2.850
1.800
1.050
±
1.00
0.223
1.517---0.583
0.000
19
2.550
1.684
0.866
±
1.72
0.397
1.807---0.140
0.024
20
2.250
1.421
0.829
±
1.15
0.264
1.450---0.341
0.003
SEM:
standard
error
of
the
mean,
95%
CI:
95%
confidence
interval.
Table
2
Comparison
of
the
difference
in
VAS
pre-WBC
from
the
first
session
to
the
subsequent
ones.
Session
Session
Mean
difference
SEM
95%
CI
p
value
12
1.350
0.272
0.136---2.564
0.016
3
1.300
0.219
0.322---2.278
0.002
4
1.850
0.302
0.503---3.197
0.001
5
1.800
0.511
−0.483---4.083
0.432
6
2.550
0.510
0.270---4.830
0.015
7
2.125
0.438
0.167---4.083
0.021
8
2.850
0.412
1.008---4.692
0.000
9
2.650
0.399
0.866---4.434
0.000
10
3.050
0.467
0.962---5.138
0.001
11
3.150
0.406
1.337---4.963
0.000
12
3.400
0.328
1.936---4.864
0.000
13
3.350
0.418
1.480---5.220
0.000
14
3.400
0.320
1.972---4.828
0.000
15
3.450
0.394
1.690---5.210
0.000
16
3.800
0.468
1.709---5.891
0.000
17
3.750
0.397
1.978---5.522
0.000
18
4.150
0.431
2.224---6.076
0.000
19
4.450
0.420
2.574---6.326
0.000
20
4.750
0.464
2.677---6.823
0.000
SEM:
standard
error
of
the
mean,
95%
CI:
95%
confidence
interval.
perceived.
PTP
measurements
using
algometry
supports
these
results.
Banfi
et
al.
described
the
effects
of
the
WBC
on
the
immune
and
inflammatory
system,
inducing
a
decrease
in
IL-8
and
other
inflammatory
factors
and
an
increase
in
anti-inflammatory
substances
like
IL-10.20
In
this
study,
we
observed
a
significant
variability
in
the
measured
values
of
inflammatory
and
anti-inflammatory
factors
during
the
20
sessions,
representing
an
obsta-
cle
for
the
analysis
of
the
anti-inflammatory
effect
of
exposure
to
WBC.
A
trend
toward
increased
IL-10
was
found,
which
is
consistent
with
what
has
been
described
in
the
literature.
However,
such
changes
were
not
statis-
tically
significant.
There
were
no
significant
changes
in
IL1␤
and
IL-6
during
this
study,
which
also
coincides
with
the
above
described.
In
contrast,
IL-8
showed
a
tendency
to
increase
during
the
study,
which
does
not
coincide
with
the
literature,
although
this
change
was
also
not
statistically
significant.

Cryotherapy
and
myofascial
pain
syndrome
119
Table
3
Difference
in
pressure
pain
threshold.
Session
Pre-mean
(kg/cm2/s)
Post-mean
(kg/cm2/s)
Mean
±
SD
SEM
95%
CI
p
value
1
1.430
1.748
0.318
±
0.23
0.050
0.195---0.405
0.000
2
1.575
1.829
0.254
±
0.23
0.050
0.139---0347
0.000
3
1.665
1.900
0.235
±
0.16
0.036
0.149---0.299
0.000
4
1.620
1.914
0.294
±
0.17
0.037
0.182---0.333
0.000
5
1.725
1.940
0.215
±
0.18
0.041
0.129---0.301
0.000
6
1.795
2.000
0.205
±
0.20
0.456
0.110---0.300
0.000
7
1.805
2.120
0.315
±
0.26
0.059
0.192---0.438
0.000
8
1.785
2.070
0.285
±
0.23
0.051
0.178---0.392
0.000
9
1.890 2.105 0.215
±
0.19 0.041
0.127---0.303
0.000
10
1.810 2.045 0.235
±
0.21 0.046 0.139---0.331
0.000
11
2.020 2.165 0.145
±
0.18 0.040 0.061---0.229 0.000
12
2.080
2.310
0.230
±
0.23
0.051
0.124---0.336
0.000
13
2.040
2.310
0.270
±
0.15
0.034
0.199---0.341
0.000
14
2.020
2.195
0.175
±
0.18
0.041
0.090---0.261
0.000
15
2.145
2.430
0.285
±
0.18
0.041
0.200---0.370
0.000
16
2.185
2.355
0.170
±
0.18
0.040
0.085---0.255
0.000
17
2.275
2.575
0.300
±
0.27
0.060
0.175---0.425
0.000
18
2.265
2.460
0.195
±
0.11
0.025
0.144---0.246
0.000
19
2.415
2.658
0.243
±
0.17
0.040
0.158---0.326
0.000
20
2.485
2.705
0.220
±
0.14
0.033
0.147---0.284
0.000
SEM:
standard
error
of
the
mean;
mean
±
SD:
mean
±
standard
deviation;
95%
CI:
95%
confidence
interval;
bilateral
p
value
is
shown.
Table
4
Comparison
of
the
difference
of
Pressure
Pain
Threshold
measured
pre-WBC
comparing
the
first
session
to
subsequent
ones.
Session
Session
Mean
difference
kg/cm2/s
SEM
95%
CI
p
value
12
0.145 0.052 0.378---−0.088
1.000
3
0.235
0.055
0.482---−0.012
0.084
4
0.190
0.086
0.575---−0.195
1.000
5
0.295
0.060
0.563---0.027
0.018
6
0.365
0.090
0.769---−0.039
0.134
7
0.375
0.077
0.719---0.031
0.020
8
0.355
0.066
0.649---0.061
0.006
9
0.460
0.089
0.856---0.064
0.010
10
0.380
0.115
0.895---−0.135
0.722
11
0.590
0.086
0.972---0.208
0.000
12
0.650
0.107
1.127---0.173
0.001
13
0.610
0.088
1.004---0.216
0.000
14
0.590
0.111
1.087---0.093
0.008
15
0.715
0.101
1.168---0.262
0.000
16
0.755
0.081
1.118---0.392
0.000
17
0.745
0.091
1.253---0.437
0.000
18
0.835
0.097
1.269---0.401
0.000
19
0.985
0.080
1.341---0.629
0.000
20
1.055
0.089
1.454---0.656
0.000
SEM:
standard
error
of
the
mean,
95%
CI:
95%
confidence
interval.
It
is
known
that
CPK
is
a
muscle
enzyme
whose
concentra-
tion
in
blood
rises
in
various
circumstances
related
to
muscle
injuries
such
as
those
that
occur
in
rhabdomyolysis
or
phys-
ical
training.
Banfi
et
al.
also
described
the
decrease
of
this
enzyme
after
exposure
to
WBC.
In
our
study,
we
observed
that
CPK
tended
to
decrease
in
blood.
However,
these
data
were
not
significant.20 Regarding
the
effect
on
cortisol,
our
study
also
did
not
show
significant
changes
during
the
20
sessions.
The
authors
attribute
this
absence
of
homogeneity
and
the
amplitude
of
the
results
due
to
the
lack
of
rigorous
con-
trol
in
the
blood
sampling
schedule,
which
may
have
been
affected
by
the
circadian
cycle
of
these
biomarkers.
Also,
we
did
not
consider
other
factors
that
may
have
contributed
to
the
physiological
variability
of
these
substances’
concentra-
tion,
such
as
the
practice
and
intensity
of
physical
activity,
the
stage
of
the
menstrual
cycle,
or
the
presence
of
conco-
mitant
diseases.
Considering
that
the
pain
perceived
by
the

120
Ó.A.
García-Espinoza
et
al.
Table
5
Mean
levels
of
serum
cytokine
concentration
throughout
the
study.
Session
IL-1␤pg/mlMean
(SD)
IL-10pg/mlMean
(SD)
TNF␣pg/mlMean
(SD)
CPKU/lMean
(SD)
CORTISOLng/mlMean
(SD)
Initial
65.62
(62.67) 8.60
(0.78)
29.82
(11.35)
567.56
(862.53)
1.83
(1.30)
4
50.74
(32.98)
8.60
(0.63)
26.93
(4.00)
278.96
(146.84)
2.35
(1.21)
8
65.59
(39.32)
8.65
(0.59)
31.94
(17.32)
283.51
(159.51)
3.53
(4.63)
12
56.33
(35.97)
8.73
(0.73)
31.70
(17.76)
288.15
(154.19)
2.24
(1.49)
16
96.40
(128.52)
8.64
(0.66)
30.71
(10.96
321.68
(205.43)
1.92
(1.00)
20
79.64
(48.02)
8.74
(0.58)
29.26
(7.09)
284.70
(181.77)
3.88
(6.42)
IL:
interleukin;
TNF:
tumor
necrosis
factor;
CPK:
creatine
phosphokinase;
SD:
standard
deviation.
Table
6
Range
of
distribution
of
serum
cytokines
concentration
throughout
the
study.
Session
IL-6pg/mlMedian
(IQR)
IL-8pg/mlMedian
(IQR)
Initial
12.63
(11.74---14.70)
26.73
(21.25---146.85)
4
12.27
(11.82---13.35)
24.89
(19.22---77.79)
8
12.54
(12.06---13.32)
26.34
(21.45---176.15)
12
12.54
(11.55---13.21)
50.38
(22.26---200.82)
16
13.43
(11.84---24.18)
89.74
(31.57---1195.78)
20
13.01
(12.24---15.25)
65.39
(23.37---242.76)
IL:
interleukin;
IQR:
interquartile
range
25%---75%.
Table
7
Comparison
of
the
difference
between
initial
and
subsequent
serum
cytokine
concentration
per
session
throughout
the
study.
Session
Mean
difference
SEM
95%
CI
p
value
IL-1␤14
−14.88
14.99
16.49---−46.24
0.333
8
−0.03
15.43
32.27---−32.33
0.998
12
−9.29
14.73
21.55---−40.12
0.536
16
30.78
31.13
95.94---−34.38
0.335
20
14.02
17.14
49.90---−21.86
0.424
IL-10 14
0.00
0.15
0.30---−0.31
0.973
8
0.05
0.19
0.45---−0.35
0.807
12
0.13
0.21
0.56---−0.28
0.558
16
0.04
0.22
0.50---−0.42
0.872
20
0.14
0.20
0.55---−0.28
0.500
TNF␣14
−2.36
1.89
1.58---−6.30
0.226
8
1.75
4.73
11.65---−8.15
0.715
12
2.42
5.04
12.96---−8.13
0.637
16
1.43
3.19
8.11---−5.26
0.660
20
−0.03
3.06
6.38---−6.43
0.993
CPK 14
−288.61
176.11
80.00---−657.21
0.118
8
−284.05
188.70
110.92---−679.01
0.149
12
−279.41
175.74
88.41---−647.24
0.128
16
−245.88
160.24
89.51---−581.27
0.141
20
−282.86
166.58
65.80---−631.53
0.106
CORTISOL 14
0.52
0.32
1.20---−0.16
0.127
8
1.70
1.06
3.91---−0.52
0.126
12
0.41
0.30
1.05---−0.23
0.195
16
0.09
0.19
0.48---−0.30
0.641
20
2.05
1.46
5.10---−0.99
0.175
SEM:
standard
error
of
the
mean,
95%
CI:
95%
confidence
interval.
patient
and
objectively
measured
pressure
pain
had
a
sig-
nificant
decrease
over
the
course
of
the
WBC
sessions,
and
was
cumulative
even
after
the
sixth
session,
it
might
be
suggested
to
consider
total
body
cryotherapy
for
myofascial
syndrome
of
the
trapezium
as
a
treatment,
requiring
more
than
6
sessions
of
WBC.
It
remains
to
be
determined
whether
myofascial
syn-
drome
anywhere
else
in
the
body
could
be
improved
with

Cryotherapy
and
myofascial
pain
syndrome
121
Table
8
Comparison
of
the
distribution
values
between
the
initial
and
subsequent
sessions
blood
test
parameters
throughout
the
study.
Session
Mean
rank
Sum
of
ranks
Z
p
value
IL-6 14
PR
9.38
75 −1.120 0.263
NR
11.25
135
8
PR
9.36
103 −0.075 0.940
NR
11.89
107
12
PR
9.10
91 −0.523 0.601
NR
11.90
119
16
PR
10.92
142 −1.381 0.167
NR
9.71 68
20
PR
11.92 73 −1.419 0.156
NR
8.38 67
IL-8 14
PR
12.17
73 −1.195
0.232
NR
9.79
137
8
PR
11.20
112 −0.261
0.794
NR
9.80
98
12
PR
12.63
101 −0.149
0.881
NR
9.08
109
16
PR
11.73
129 −0.896
0.370
NR
9.00
81
20
PR
11.00
110 −0.187 0.852
NR
10.00
100
PR:
positive
ranks,
NR:
negative
ranks.
this
therapy,
if
the
analgesic
effect
lasts
after
sessions
end
and
if
it
is
superior
to
other
treatments.
Therefore,
it
is
rec-
ommended
to
continue
this
line
of
research
to
validate
this
effect
with
a
case-control
study
and
long-term
follow-up.
This
study
has
some
limitations.
A
control
group
was
not
included,
making
it
difficult
to
accurately
determine
the
positive
effect
of
patients
upon
the
application
of
full-body
cryotherapy,
as
well
as
the
role
of
the
placebo
effect.
Sim-
ilarly,
the
study
sample
consisted
of
a
homogeneous
group
of
patients
with
trapezius
myofascial
pain
syndrome;
there-
fore,
it
would
be
important
to
evaluate
the
effect
of
total
body
cryotherapy
on
myofascial
syndrome
in
other
areas
of
the
body.
Although
we
asked
patients
to
suspend
any
anal-
gesic
measures
(drugs
and
physical
therapy),
we
did
not
supervise
this
variable
outside
the
clinic,
but
we
did
encour-
age
honesty
from
the
patient.
Finally,
no
follow-up
data
was
collected,
so
it
is
not
possible
to
determine
the
duration
of
the
analgesic
effect.
Conclusion
The
findings
in
this
study
show
statistically
significant
data
on
the
analgesic
effects
of
whole
body
cryotherapy
in
patients
with
myofascial
syndrome,
as
evidenced
by
the
decrease
in
perceived
pain
(VAS)
and
measured
pain
(PPT).
Despite
its
limitations,
this
study
suggests
that
WBC
is
an
effective
treatment
for
the
reduction
of
pain
in
myofascial
syndrome
of
the
trapezius.
It
is
important
to
extend
the
research
of
its
use
in
other
areas
of
the
body,
its
compari-
son
with
a
control
group,
and
the
duration
of
its
therapeutic
effect,
to
be
considered
a
feasible
therapy.
Ethical
disclosures
Protection
of
human
and
animal
subjects.
The
authors
declare
that
the
procedures
followed
were
in
accordance
with
the
regulations
of
the
relevant
clinical
research
ethics
committee
and
with
those
of
the
Code
of
Ethics
of
the
World
Medical
Association
(Declaration
of
Helsinki).
Confidentiality
of
data.
The
authors
declare
that
they
have
followed
the
protocols
of
their
work
center
on
the
publica-
tion
of
patient
data.
Right
to
privacy
and
informed
consent.
The
authors
declare
that
no
patient
data
appear
in
this
article.
Funding
Financing
was
carried
out
through
in-house
resources
of
the
Department
of
Sports
Medicine
and
Physical
Rehabilitation
of
the
‘‘Dr.
Jose
Eleuterio
Gonzalez’’
University
Hospital
of
the
Universidad
Autonoma
de
Nuevo
Leon.
Conflicts
of
interest
The
authors
have
no
conflicts
of
interest
to
declare.
Acknowledgments
The
authors
would
like
to
thank
Sergio
Lozano-Rodríguez,
M.D.
for
his
help
in
the
translation
and
editing
of
this
manuscript,
and
Nery
Alvarez,
M.D.
for
his
knowledge
and
help
in
statistical
analysis.

122
Ó.A.
García-Espinoza
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