GATE CONTROL THEORY OF PAIN

What occurs at the cellular level when pain is experienced? The gate control theory of pain, by P. D. Wall and Ronald Melzack, offers a useful model of the physiological process of pain. Gate control is recognized as a major pain theory.

According to the gate control theory, pain is a balance between information traveling into the spinal cord through large nerve fibers and information traveling into the spinal cord through small nerve fibers. Without any stimulation, both the large and small nerve fibers are quiet, and the substantia gelatinosa (SG) blocks the signal to the transmission cell (T cell) connected to the brain. The “gate is closed,” and there is no pain. With pain stimulation, small nerve fibers are active. They activate the T-cell neurons but block the SG neuron, making it impossible for the SG to block the T-cell transmission to the brain. The result is that the “gate is open”; therefore, there is pain. In other words, pain is experienced whenever the substances that tend to propagate a pain impulse across each “gate” in a nerve pathway overpower the substances that tend to block such an impulse.

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The gate control theory of pain transmission

FIGURE. The gate control theory of pain transmission. The substantia gelatinosa (SG) accepts input both from large-diameter (nonpain) and small-diameter (pain) nerves. Based on the rate of input, the SG allows either the pain or nonpain stimulus to be passed on to the transmission cell (T cell) and up to the brain. Because nonpain impulses travel faster than pain impulses, stimulation of nonpain fibers can override the transmission of pain. In addition, the brain has an inhibiting influence both on the SG and the spinal cord that can work to limit the perception and reaction to pain. (From Starkey, C: Therapeutic Modalities for Athletic Trainers. FA Davis, Philadelphia, 1993, p 28, with permission.)

Studies of coping factors support a wider version of the gate control theory. These factors are to be considered before determining treatment for pain, and they raise a number of questions.

  1. How well is the client experiencing life?
  2. Does the client have pain, and if so, does he or she think that it is under control?
  3. Does the client feel adequately informed about the painful condition?
  4. Is the client occupied? How does the individual fill his or her time?
  5. Is the client coping with other problems?
  6. Does the client feel dissatisfied with his or her past life, or does he or she have any substantial regrets?
  7. Are there any reasons why the client may not be coping?
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Answers to these questions may help determine the best treatment protocol for pain.

Spine Health. PROCEDURE 10 — ROTATION MANIPULATION IN EXTENSION The patient lies prone as for procedure 1. The therapist stands to one side of the patient and, having selected the correct segment, places the hands on either side of the spine as for the technique of rotation mobilisation in extension (procedure 9), which is always applied as a premanipulative testing procedure. The information obtained from the mobilisation is vital and determines on which side and in which direction the manipulation is to be performed. If following testing the manipulation is indicated, the therapist reinforces the one hand with the other on the appropriate transverse process. The manipulation is then performed as in procedure 8. Fig. Rotation manipulation in extension. Effects: The effects of the external force and the reasons for its use are the same as for procedure 9. When the desired result is not obtained with the mobilising technique, manipulation is indicated under certain circumstances. Regarding the direction in which the manipulation is to be...
Back Pain. Diagnosis THE THERAPIST’S RESPONSIBILITY The therapist is part of the team involved in the treatment and rehabilitation of patients suffering low back pain. In some countries manipulative therapists are primary contact practitioners. Consequently, their diagnostic skills have greatly improved, enabling them to define which mechanical conditions can be helped by mechanical therapy and to separate these conditions from the nonmechanical lesions which have no place in the therapy clinic. However, differential diagnosis is really not within the scope of manipulative therapy. It is my view that differential diagnosing by medical practitioners is necessary to exclude serious and unsuitable pathologies from being referred for mechanical therapy. In making diagnoses the manipulative therapist should confine himself to musculo-skeletal mechanical lesions. Specialised in this field, he is usually able to make far more accurate diagnoses than most medical practitioners. As the manipulative therapy prof...
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Back Pain History Taking an accurate history is the most important part of the initial consultation when one is dealing with any medical or surgical problem. Unfortunately, when the mechanical lesion is involved there is still lack of understanding regarding the nature of the questions that should be asked, the reasons for asking them, and the conclusions to be drawn from the answers. I will set out step by step the stages that should be developed in history taking, and the questions that should be asked at each stage. Practitioners will already have their own method of history taking, and I do not suggest at all that they should alter their routine. However, I believe that the following questions must be included, if one is to reach a conclusion following the examination of patients with mechanical low back pain. INTERROGATION As well as the usual questions regarding name, age and address, one should enquire as to the occupation of the patient, in particular his position at work which provides us ...
Spinal manipulation techniques There are many differing philosophies and concepts surrounding the practise of spinal manipulation and its effects on the pathologies which may exist in the spine. To satisfy all these philosophies an equal number of institutions has developed, teaching those wishing to learn. No matter what school presents its case or which philosophy is adhered to, all manipulative specialists claim to have a high success rate. They all use techniques which vary in nature, application and intent; they proclaim that their own methods are superior to those used by others; and yet, somehow they all obtain uniformly good results. Self-limitation of low back pain plays, of course, a significant role in this happy situation. Apart from this there are definite benefits which are obtained quickly by using manipulative techniques. Throughout the years I have practised many forms of mobilisation and manipulation, including osteopathic and chiropractic techniques and those taught by Cyriax. I have come to be...