Physical Agents utilized in Physical
Medicine and Rehabilitation
C. Scott Bickel, PT, PhD
Department of Physical Therapy
School of Allied Health Professions
LSU – Health Sciences Center
May 13, 2005
Modalities
• APTA’s position statement (1995):
– “Without documentation which justifies the
necessity of the exclusive use of physical
agents/modalities, the use of physical
agents/modalities in the absence of other
skilled therapeutic or education intervention,
should not be considered physical therapy.”
Physical Agents
– Heat
– Cold
– Water
– Pressure
– Sound
– Electrical Current
General Indications
• Purported Uses
– Modulate pain
– Reduce or eliminate inflammation
– Increase rate of healing
– Modify muscle tone
– Increase connective tissue extensibility
Commonly used modalities
• Temperature modalities
– Cryotherapy - ice
– Heat
• Superficial – hot packs
• Deep - Ultrasound
– phonophoresis
• Electrical stimulation
– TENS
– Iontophoresis
– NMES
Less commonly used modalities
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•
•
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EMG Biofeedback
Spinal Traction
Short-wave diathermy
Infrared
Cryotherapy
• Historical perspective
– Ancient Greeks and Romans
– Late 1880’s, cold compresses after surgery
– Early 1960’s, cold therapy widely recognized
by healthcare as a result of studies by Grant
(1964) and Hayden (1964).
• Military studies.
Cryotherapy
• Why Ice?
– Mild cooling often used in an effort to control:
• Inflammation
• Pain control
• Reduce spasticity
• RICE
– Ice probably more effective than cold packs.
Cryotherapy
Ice
• Vasoconstriction
– Immediate vasoconstriction
– 10-15 minutes
• Vasodilation?
• Slows the acute inflammatory response
– Reduced tissue temperature
• Slows rate of chemical reactions
• Immediate application
• Reduces pain
Ice
• Contraindications
– Cold hypersensitivity
– Raynaud’s disease
– Regenerating
peripheral nerves
– PVD
• Precautions
– Over superficial main
branches of nerve
• Peroneal nerve
– Open wounds
– Poor sensation
Ice evidence
• Temperature will drop from skin to ~2-7 cm
deep. (MacAuley et al 2001)
• 10 minutes is sufficient.
• Several studies – immediate application of
ice after ankle sprain = quicker return to
sport
Superficial Heat
• Often used for:
– pain control
– increase tissue extensibility
• Done prior to or in conjunction with other
treatments.
Heat
Superficial Heat
• Vasodilation (Bickford and Duff 1953 and others)
– Increased blood flow
– Primarily a local effect
• Increase tissue extensibility (Lentell et al 1992)
– Cannot stretch a cold muscle
• Can heat a muscle with exercise
• Increase metabolic processes
• Pain control
– Primarily a local effect
Superficial Heat
•
•
•
•
Hot packs
Paraffin wax
Hydrotherapy
Timeframe = ~20 minutes
• Contraindications
–
–
–
–
Acute injury
Patients with impaired sensation
Heat near malignant tissue
In area of thrombophlebitis
Ice or Heat
• Ice – acutely (<24-48 hours), then can
move to heat if desired.
• Symptomatic relief.
– Heat Vs. Cold
• If assists in pain relief they can be utilized
at home.
Ultrasound
• Therapeutic Ultrasound sends high
frequency sound waves through tissue
and has a thermal effect.
• Deep heat
– 2-5 cm
– 1 MHz - 5cm / 3 MHz - 2cm
• Ultrasound head is small, so can only heat
a fairly small area (2x size of soundhead)
Ultrasound
• Typical applications of Ultrasound
– Pain control (Munting 1978)
– Increase tissue extensibility (Knight 2001)
– accelerate healing
• Wounds (Dyson 1978), bone fractures (Duarte 1983)
– Phonophoresis
• Application of ultrasound in conjunction with a
topical drug preparation for enhanced delivery
– (ex. hydrocortisone).
• Enhanced delivery (McNeill et al Pharm Res 1992)
Questions?
Electrical Stimulation
• Common uses:
– Pain control (TENS, interferential)
– Iontophoresis (Direct Current)
– Muscle stimulation (NMES)
– Tissue healing (wound care)
Electrical Stimulation
• Main parameters to be familiar with
– Frequency
• Muscle – force/frequency relationship
– Pulse Duration
• Strength Duration curve
Force Frequency Relationship
50-60 Hz – force levels off
Strength / Duration
Levels of stimulation
TENS
• Transcutaneous Electrical Nerve Stimulation
– Used for Pain control
• 2 theories of how TENS may control pain
– Gate control theory – high frequency TENS
– Opiate-mediated control – low frequency TENS
TENS
• Gate-control theory of pain modulation
– Ex. Bump your head, you rub it.
From Kandel, Schwartz, and Jessell
Principles of Neural Science
TENS
• Opiate-mediated control
– Endorphins
• E-stim may promote endorphin release.
– Cats
– Non-human primates
TENS evidence
• Which answer do you want?
• Deyo et al. A controlled trial of TENS and
Exercise for Chronic LBP. New Eng J. Med.
1990.
– 4 groups
• TENS
• TENS + exercise
▪ sham TENS
▪ sham TENS + exercise
– Exercise groups did better than TENS
– TENS added no additional benefits
TENS evidence
• Chabal et al. Long-term TENS Use:
Impact on Medication Utilization and PT
costs. Clin. J. of Pain. 1998
• 376 patients
– TENS vs. no TENS
– TENS group had 55% and 69% reduction in
costs for medications and PT, respectively.
Iontophoresis
• Iontophoresis – use of direct current to
enhance transcutaneous administration of
ionizable substances.
• Most commonly used:
– Dexamethasone – anti-inflammatory agent
• Conditions:
– Epicondylitis, tendonitis, etc…
Iontophoresis evidence
• Nirschl RP et al. Iontophoretic admistration of
dexamethasone sodium phosphate for acute
epicondylitis. AJSM, 2003
• Randomized, double-blind, placebo-controlled
trial.
–
–
–
–
199 patients with acute epicondylitis
Ionto 40 mA-minutes of treatment 3/wk x 2 wks
Short-term f/u – ionto significantly improved
By 1 month – no diff b/t groups
Muscle Stimulation (NMES)
• Specific Uses:
– Facilitation of muscle contractions
– NMES for restricted joint motion and
contractures
– NMES to control spasticity
– Functional electrical stimulation
Muscle re-education and facilitation
• Goal – re-establish “normal” voluntary
motor control.
• Typically patient tries to perform the
contraction or desired movement along
with the stimulation.
• Data – may or may not be better than
voluntary exercise alone.
NMES for restricted joint motion
and contractures
• PROM
– Some evidence suggests E-stim may help:
• Knee flexion contractures
• Wrist/finger flexion contractures after CVA
• Typical protocol:
– 30 mins, 3 times/day, 7 days/week, 4 weeks.
– “maximum comfortable extensor contraction”
NMES to control spasticity
• How is spasticity reliably measured?
• For example (Peterson and Klemar, 1988)
– Spastic plantar flexors.
– Stimulated the tibialis anterior
– 2-3 seconds on/10 seconds off for 30 minutes
– Reduced spasticity for up to 6-14 hours.
• Reciprocal inhibition – activate the
antagonist and this may produce an
inhibition to the spastic muscle and
therefore reduce spasticity.
Functional Electrical Stimulation (FES)
• FES – the use of e-stim to produce limb
movements important for ADL can be
considered FES.
• Example: prevent shoulder subluxation
during movements or to produce
dorsiflexion during gait.
Functional Electrical Stimulation (FES)
• Can e-stim be used to make people walk?
– Complete SCI?
• Parastep.
– May not get very far due to fatigue.
– Patients may find it easier to get around in the
wheelchair.
Parastep
Muscle fatigue with NMES
Tibialis anterior
Vs.
Quadriceps femoris
Bickel et al, 2003
Functional Electrical Stimulation (FES)
• In SCI patients, e-stim has been shown to:
– Evoke training responses like:
• Increase VO2
• Increase muscle mass
• Improve muscle endurance
• Muscle Plasticity
– Give the appropriate stimulus, can evoke
changes!
Muscle Hypertrophy after
SCI?
• Is it possible to evoke muscle
hypertrophy after complete SCI?
• Studies have reported modest
hypertrophy (0-20%). Cycling exercise
has been reported to increase muscle
area by 12%.
– Is this the appropriate exercise?
– Is 12% enough?
Acute SCI (< 1 yr), n=3
% CSA of AB
80
75
70
65
60
EMS
55
0
10
20
30
40
50
60
Time (weeks after injury)
4 sets of 10
2 days per week for 8 weeks
Total contractions = 640
Dudley et al. 1999
Chronic SCI
•6 males, Complete SCI (ASIA A)
•Levels of injury = C5-T9
•Duration of injury = 12 ± 7 yrs (5-21 y)
•Age = 34.8 ± 4.8 yrs. (28-41 y)
•Body mass = 82.0 ± 23.3 kg (59.8-111.8 kg)
Chronic SCI
Training
24 weeks of training, 2 days per week
Electrical stimulation (ES) was used to activate primarily the QF muscle
group (30 Hz trains of 450 µsec biphasic pulses)
ES amplitude was increased to evoke 4 sets of 10 dynamic knee
extensions
Ankle weights were used as progressive loading over training protocol
All training was performed at subjects’ homes
An investigator provided instruction by telephone
Region of interest
Results
After 6 months of training:
Right QF muscle CSA increased from 34 ± 10cm2 to 58 ± 14cm2 (p = 0.004)
Left QF muscle CSA increased from 36 ± 11cm2 to 62 ± 17. cm2, (p = 0.002)
This equated to ~70% increase in QF muscle size in both thighs
Before
After
A single slice (MRI) of the right thigh from 1 subject, before and after training.
QF muscle size of the left leg at 0, 3,
and 6 months of electrically stimulated
RT (n = 6).
90.0
*‡
80.0
50.0
40.0
2
60.0
Muscle CSA (cm )
70.0
30.0
20.0
* p=0.002, 6 Mo. vs. PRE
10.0
‡ p=0.002, 6 Mo. vs. 3 Mo.
0.0
PRE
3 MONTH
6 MONTH
Muscle Hypertrophy/SCI
• 6 months of training – QF muscle nearly
the size of AB controls
• Health benefit:
– Improved glucose tolerance in subjects with
impaired OGTT
• Improved exercise capacity?
Fatigue Resistance
• Electrical stimulation of SCI muscle has
been shown to:
– Increase type IIa fibers
– Increase capillary density
– Increase enzymes of energy supply
– Increase fatigue resistance
• Same principles can be applied to other
conditions.
Electrical Stimulation after ACL
• Snyder-Mackler et al. Strength of the QF muscle
and Functional Recovery after ACL
reconstruction. JBJS. 1995.
– RCT of Electrical Stimulation vs volitional ex.
– 110 patients seen first 6 weeks post-op.
• ES group - 70% recovery of QF function
• Volitional group – 56% recovery of QF function
– Key to study – stimulation was done at high
intensities
Summary
• Modalities are used fairly frequently. Most
used for pain control to treat the
symptoms, rarely will be a long-term
solution.
• Electrical stimulation has shown promise
in the treatment of muscle after injuries
(SCI, ACL, etc…)
Questions?
More info:
C. Scott Bickel, PT, PhD
cbicke@lsuhsc.edu
568-4288