Gate Theory or Gait Theory?

A complex amalgam of nerves and synapses exists throughout the human body. These electrical impulses are the body's communication system, sending millions of messages across millions of nerve pathways. Any conscious or subconscious act is linked to an intricate neurological reaction jumping between nerves, eventually reaching the brain in a recognizable form.

Sometimes, those messages are undesirable and arrive at the brain as pain impulses. Pain is the body's warning system, alerting us to illness or injury, and it is the duty of the health care practitioner to offer therapies that change those undesirable signals into therapeutic benefit. Many chiropractors use some form of electrotherapy in their offices. Although their use is widespread in the treatment of numerous ailments, there are many detractors who question the innumerable side-effects and complications that can occur if not utilized correctly. Most of the time, the need for these procedures can be reduced or even eliminated through the use of orthotics.

By altering electrical impulses in the body, electrotherapy devices help control pain and aid in muscle re-education. Commonly, electrotherapeutic procedures are utilized in a chiropractic practice when patients present with myofascial spasm and laxity, strains and sprains, and hyper- and hypotonicity. They are often used to increase vascular flow and support the subluxation complex.¹

In 1965, modern electrotherapy began its journey when Ron Melzack and Pat Wall published their gate control theory of pain reduction, which suggests that pain perception depends on the balance of large- and small-diameter nerve fiber activity. Elevated large nerve fibers can "close the gate" to information traveling to the brain, including pain signals. Electricity, they believed, was the key to closing that gate.² In the 1980s, Robert Becker, MD, discovered that humans are negatively charged in the extremities and positively charged along the central nervous system, although the motor and sensory nerves are more negatively charged distally.³ In his article, "Current Trends," Robert Picker, MD, reported that many users believe the positive pole has a more anti-inflammatory physiological effect, while the negative pole has a vasodila-tive effect, which can be helpful with muscle spasms and contracted scar tissue. The positive pole is used more often with acute injuries, and the negative pole with chronic neuromuscular symptoms. One of the easiest ways to remember this is by thinking of positive as ice, which causes constriction, and negative as heat, which causes dispersal.¹

The most common forms of electrotherapy used in chiropractic clinical practice are:

TENS - transcutaneous electrical nerve stimulation - involves the use of two electrodes, attached to the skin over the painful areas, and a black box (a small, battery-powered pulse generator). Even though no mechanism of action can be proven for their use, TENS units often provide considerable relief of chronic, nonresponsive pain, and they have become an accepted item in the chiropractor's office.⁴

MENS - microcurrent electrical nerve stimulation - works on a cellular level and aids in the healing process while relieving pain. MENS devices are thought to work by increasing the level of adenosine triphosphate (ATP) in the affected sites, thus promoting protein synthesis and healing in tissue cells. These procedures are very effective in the acute phase of muscle spasm and inflammation, and in the chronic stage of tissue regeneration.¹ Electroacu-puncture procedures are commonly used with microcurrent therapy in treating muscle spasms; motor function; mucous membranes; skin; mechano nerve receptors; lymphatic tissue; golgi tendon/ spindle cell fibers; and pain control.¹

High-voltage galvanic therapy - used for increasing circulation or reducing edema in a specified area. Its related devices also can be used for wound care.

Interferential therapy - used to manage deep, chronic pain using a high-pulsed current. This higher frequency goes through the skin and muscle better than other modalities, and can be more effective in pain control.

We have come full circle - from widespread unregulated use of electrostimu-lation devices to the total discredit of all electrical effects. Today, widespread acceptance once again predominates the chiropractic landscape. Unfortunately, the "gate theory" is no longer generally accepted, and the mechanism of how these devices actually reduce pain is still a mystery. No substantiated research has been performed on the adverse side-effects of these devices.³ In addition to skin reactions to the electrodes used during electrotherapies, high-voltage electrotherapy exposes patients' tissues to substantial electrical currents, pulsing at frequencies not normally present in the earth's electromagnetic field, often causing side-effects to occur.³

As an alternative to traditional electrotherapeutic modalities, orthotics can provide similar effects by aligning the same system of nerves and synapses. By improving posture and aligning the kinetic chain, "white noise" throughout the body can be reduced and equilibrium can be established with the central nervous system. It all begins at the feet! For years, clinicians have been using orthotics for the correction of such conditions as structural misalignment, poor posture, myospasm, shock absorption, extremity pains, short leg syndrome, Achilles tendonitis, and plantar fascitis. Since there is also a relationship between the spine and pelvis, the pelvis and legs, the pelvis and the cervical/dorsal spine, and the legs and the feet, starting at the bottom is the most sensible way to proceed. Analysis of a patient's gait can also support the decision to dispense an orthotic. In my practice, it is common to see many patients wearing custom-made flexible orthotics. To reduce myofascial spasm, proper spinal biomechanics must be in order.

In a four-month study, 10 cases were treated with orthotics and compared against 10 similar cases treated using alternative therapies. No adjustments were given. A significant improvement in spinal biomechanics, based on "before-and-after" radiological findings, was noted in patients wearing orthotics.⁴ In my own office, 20 cases were accepted in an elecromyographic (EMG) study in the 1990s - all showed significant improvement in spinal biomechanics and conductivity when wearing orthotics as an adjunct to their therapy.

In conclusion, I must share a recent case of mine. A gentleman came into my office with severe, deep-seeded psoas pain and spasm and "locking" of the head of the femur and acetabulum. This was chronic, agonizing pain, and I was the next in line to provide relief of his symptoms. Two orthopedic surgeons he had visited suggested hip replacement. One chiropractor looked at the hospital films (taken supine) and adjusted him on a program, while another chiropractor adjusted him and used electrotherapy on the psoas muscle. Both doctors relieved the patient's pain for about an hour. The patient also sought out the services of a physical therapist, who performed stretching, ultrasound and heat - also achieving positive results for about an hour.

When the gentleman first came into my office, we performed postural tests and X-rays, and the patient demonstrated a 7 mm leg deficiency. We began his treatment by casting him for orthotics and sent him home for two weeks once he had received them. The patient reported an 80 percent reduction in pain and was given corrective spinal adjustments weekly for two weeks. Currently, the patient is totally pain-free and is on a regimen of preventive care. The psoas spasm was completely resolved without the use of any electro-therapeutic devices.

Working with a level playing field is paramount when dealing with cases that lend themselves to electrotherapeutic support. Structural imbalances, once eliminated, provide a clearer picture for when the utilization of electrotherapy should be applied.

References

1. Greenlee CW. Basic Microcurrent Therapy (4th ed.). Kelseyville, Calif: Earthen Vessel Productions, 1998.
2. Becker RO. Cross Currents. 1990. New York: JP Tarcher, 1991.
3. Christensen KD. Clinical Chiropractic Biomechanics (2nd ed.). Dubuque, Iowa: Foot Levelers Educational Division. 1984.
4. Walsh DM. TENS Clinical Applications and Related Theory. New York: Churchill Livingstone, 1997.