Interferential
current (IFC): This type of stimulation is characterized by the crossing of two
electrical medium, independent frequencies that work together to effectively
stimulate large impulse fibers. These frequencies interfere with the
transmission of pain messages at the spinal cord level. Because of the
frequency, the Interferential wave meets low impedance when crossing the skin to
enter the underlying tissue. This deep tissue penetration can be adjusted to
stimulate parasympathetic nerve fibers for increased blood flow. Interferential
Stimulation differs from TENS because it allows a deeper penetration of the
tissue with more comfort (compliance) and increased circulation.
Interferential
current is essentially a deeper form of TENS. In essence, IFC modulates a high
frequency (4000 Hz) carrier waveform with the same signal produced by a TENS
unit. The high frequency carrier waveform penetrates the skin more deeply than a
regular TENS unit, with less user discomfort for a given level of stimulation.
Deep in the tissues, the carrier waveform is cancelled out, resulting in a
TENS-like signal deep under the skin.
Anecdotal
evidence suggests that the IFC units may be useful for patients who have not had
relief from TENS.
Interferential
electrical stimulation's is a unique way of effectively delivering therapeutic
frequencies to tissue. Conventional TENS and Neuromuscular stimulators use
discrete electrical pulses delivered at low frequencies of 2-160 Hz per second.
However, Interferential stimulators use a fixed carrier frequency of 4,000 Hz
per second and also a second adjustable frequency of 4,001-4,400 Hz per second.
When the fixed and adjustable frequencies combine (heterodyne), they produce the
desired signal frequency (Interference frequency). Interferential stimulation is
concentrated at the point of intersection between the electrodes. This
concentration occurs deep in the tissues as well as at the surface of the skin.
Conventional TENS and Neuromuscular stimulators deliver most of the stimulation
directly under the electrodes. Thus, with Interferential Stimulators, current
perfuses to greater depths and over a larger volume of
tissue than other forms of electrical therapy. When current is
applied to the skin, capacitive skin resistance decreases as pulse frequency
increases.' For example, at a frequency of 4,000 Hz (Interferential unit)
capacitive skin resistance is eighty (80) times lower than with a frequency of
50 Hz (in the TENS range). Thus, Interferential current crosses the skin with
greater ease and with less stimulation of cutaneous
nociceptors allowing greater patient comfort during
electrical stimulation. In addition, because medium-frequency (Interferential)
current is tolerated better by the skin, the dosage can be increased, thus
improving the ability of the Interferential current to permeate tissues and
allowing easier access to deep structures. This explains why Interferential
current may be most suitable for treating patients with deep pain, for promoting
osteogenesis in delayed and nonunion fractures and in
pseudothrosis, for stimulating deep skeletal muscle to
augment the muscle pump mechanism in venous insufficiency, and for depressing
the activity of certain cervical and lumbosacral
sympathetic ganglia in patients with increased arterial constrictor
tone.
Common
uses
Pre
and post-orthopedic surgery, joint injury syndrome, cumulative trauma disorders,
increasing circulation and pain control of various
origins.
Applications
Interferential
Therapy is used in the treatment of circulatory disorders, range of motion, edema and muscle spasms. Post-op
patients will use the device 3 times a day for 15 minutes over a period of 14 -
30 days.
Advantages
Since
Interferential Therapy has been in use for many years, its effectiveness is well
documented. Studies have shown that patients using Interferential Therapy after
surgery develop fewer post-op complications than those relying solely on
narcotics for pain relief. Interferential stimulation does not cause respiratory
depression. Interferential Therapy aids in circulation, increasing the recovery
time for patients. Multiple treatments at home or work will typically speed the
patient's recovery and allow earlier resumption of their normal
lifestyle.
Commonly
Asked Questions in Regards to Interferential
Therapy
Are
Interferential devices safe?
YES.
Although the thought of electrical impulses being sent into the body may seem
frightening at first, all you really feel is a slight vibrating sensation.
Unlike many drugs, Interferential devices have no known side
effects.
Who
cannot use an Interferential device?
Individuals
with a pacemaker or patients who are pregnant should not use an Interferential
device. Consult your doctor or clinician first.
Will
an Interferential device work for me?
Interferential
Therapy has been used extensively for managing post-surgical, post-traumatic
acute pain, edema and inflammation reduction. It has been used successfully for
a wide variety of procedures such as:
General
Surgery:
-
Hernia Repair
-
Gall Bladder
Neurosurgery
/ Orthopedic
-
Low Back Surgery
-
Hip/Joint Repair
-
ACL Repair
-
Carpal Tunnel
Obstetrics
/ Gynecology
-
Gynecological
-
Laparotomy
-
Cesarean Section
Orthopedic
-
Hip Replacement
-
Arthrotomy
-
Fractures
-
Sports Injuries
-
Joint Mobilization
Podiatry
-
Hammer Toes
-
Bunionectomy
-
Tarsal Tunnel
Thoracic
-
Thoracotomy
Urology
-
Nephrectomy
-
Prostatectomy
-
Penile Implants
TECHNICAL
INFO:
-
Carrier Frequency: 4000Hz., fixed
-
Interference Frequency: 4001-4150 Hz
-
Difference Frequency: 1-150 Hz., adjustable
-
Output Voltage: 0-16 volts (through 500 ohms)
-
Waveform: Symmetric biphasic square
-
Pulse Width: 125 Microseconds for each phase
-
Four Frequency Shift: Continuous, 1/1 abrupt, 8/8 abrupt, 10/10
ramped
ACCESSORIES:
-
Power Source: 9V alkaline battery and A/C Adaptor
- Lead wires
-
3 packs of 4 self-adhesive electrodes
- Hard Plastic Carrying case
- Instruction Booklet
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Interferential Therapy
