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Sciatica

The term sciatica defines the radiating pain down the leg, along the large sciatic nerve that runs from the lower back down through the buttock and along the back of each leg. Sciatica usually only affects one side of the body and the pain often radiates through the buttock, below back of the thigh and knee and may involve the foot. This radiating pain is aggravated when sitting and there may be numbness and weakness of the lower leg muscles. Although the pain from sciatica can be severe and debilitating, in some people, the pain might be infrequent and slightly irritating, but has the potential to get worse. People with sciatica may experience a burning or tingling sensation down the leg, a constant pain on one side of the buttocks and a shooting pain that makes it difficult to stand up may also occur.

 

THE CAUSE:

The inter-vertebral discs are the cushions, which separate the spinal vertebrae. These discs allow for some flexibility between the bones of the spine, and act as shock absorbers due to their soft consistency in the center (nucleus pulposus) yet tough and fibrous outer ring (annulus). However, the pressures within the discs can reach high levels when we bend or twist, even without carrying a heavy load. Imagine the increase in pressure when we add to that a heavy load, especially with our arms held out in arm’s length. If part of the fibrous outer ring of the disc is rather weaker than the rest, the softer inner core may push its way through, pressing against a nerve. Therefore, one of the most common causes of true sciatica is a prolapsed intervertebral disc (PID) or a herniated nucleus pulposus in which the herniated disc presses against the nerves, which go to make up the sciatic nerve. Other possible causative factors of sciatica include aging which causes vertebrae to become rough and enlarged and less commonly infections and tumors are responsible. The following are other common conditions that can result in pain along the sciatic nerve:

  • Lumbar spinal stenosis : is due to a narrowing of the spinal canal resulting from enlarged facet joints placing pressure on the nerve roots as they exit the spine.
  • Degenerative disc disease : during natural disc degeneration, sometimes this process can lead to pain along the sciatic nerve.
  • Isthmic spondylolisthesis : although this condition alone rarely causes pain, it occurs when a small stress fracture, usually at the fifth segment, allows the L5 vertebral body to slip forward on the S1 vertebral body. Therefore the combination of disc space collapse, the fracture, and the slipping forward of the vertebral body, the L5 nerve of the sciatic nerve can get pinched as it exits the spine.
  • Piriformis syndrome : irritation of the sciatic nerve as it runs under the piriformis muscle in the buttocks.
  • Scaroiliac joint dysfunction : the L5 nerve lies on top of the sacroiliac joint, therefore when this joint is irritated, the nerve can become irritated causing sciatica.

TRADITIONAL CHINESE MEDICINE AND ACUPUNCTURE:

In Traditional Chinese Medicine (TCM), sciatica is due to the invasion of exogenous pathogens like wind-heat, wind-cold and wind-dampness or external traumatic injuries, which result in the obstruction of qi and blood in meridians. Sciatica is a Bi syndrome and its manifestations are the same as in western medicine. Bi syndrome is mainly classified according to etiology and manifestation. The following categories of bi-syndrome are based on the dominant external pathogen (etiology): wind-bi, cold-bi, damp-bi and heat-bi. Furthermore, bi-syndromes can be classified according to their manifestation such as: wandering-bi (radiating or migrating pain), painful-bi (severe, excruciating pain) and fixed-bi (heaviness and numbness with fixed pain).

 

ETIOLOGY :

Wind is one of the six external pathogenic factors. It is likely to impair the body in combination with some other pathogenic, such as coldness, dampness, and/or heat. Invasion by wind, cold and dampness is usually induced by living in damp conditions and places, wearing clothes made wet by sweat or rain, frequent exposure to water, and periods of prolonged raining. Cold weather is also a pathogenic factor easily leading to invasion of wind-cold-damp. Invasion by wind-heat in combination with damp, or production of heat due to chronic wind-cold-damp bi, may cause obstruction of meridians and collarterals resulting in wind, damp and heat bi. Since there is, obstruction of channels there would be accompanying pain. If the illness is prolonged, and the tendons and muscles lose the nourishment from qi and blood, there would be atrophy, numbness, cold pain or burning sensation of the gluteal muscles and the thigh and lower leg muscles. Internally, a deficiency of kidney yang can give rise to cold and damp syndromes affecting the lower body. In this case, external wind may not be a factor in causing the pain, though it can still combine with cold and dampness to exacerbate the underlying condition. External traumatic injuries also contribute to sciatica because it can result in blood stasis obstructing the meridians and collaterals.

 

DIFFERENTIATION OF SYNDROMES :

The pain along the pathway of the sciatic nerve is the major symptom and other symptoms include numbness in the above regions worse with standing, walking or exercise, back pain that radiates to the legs and weakness of the legs. There are tender spots along the paraspinal muscle (BL25, BL26), Gluteus muscles (GB29, GB30), Hamstrings (BL56), Gastroscenimus (BL57), Achilles Tendon (BL60). In Traditional Chinese Medicine, each type of Bi syndrome is manifested by different signs and symptoms:

  • Wind-Cold-Damp : as a bi-syndrome, it is fixed, severe and cold pain in the lumbar region and legs. Movement is limited when bending forward and backward as well as turning. It is aggravated on cloudy, rainy and cold days.
  • Wind-Damp-Heat : characterized by burning sensation in the limb, which is aggravated by heat.
  • KD-Yang Deficiency : pain is dull and lingering and is worsened by overwork. Weakness of the loins and knees, lassitude and listlessness.
  • Qi stagnation and Blood Stasis due to Traumatic Injury : Severe fixed prickling pain in the lumbar region and leg, aversion to pressure. The pain often gets worse at night.

TREATMENT PRINCIPLE AND METHODS :

  • Acupuncture will help to relax tendons and muscles, remove the pathogen and promote the circulation of the qi and blood to relieve pain. If the condition is acute, the treatment course may be 6 to 8 treatments, twice a week. However, for chronic conditions, the treatment course may be longer. Other treatments which the practitioner may combine with the acupuncture are:
  • Ear Acupuncture : 2-3 points, with moderate to strong stimulation by needling, or using intradermal needles are used on the following auricular points: Sciatica, Adrenal Gland, Buttocks, Shenmen, Lumbar/Sacral Vertebrae
  • Electro-Acupuncture : 2-3 pairs of points are selected from regular acupuncture prescription for stimulation with high frequency dense wave (for approximately 10 minutes).
  • Scalp Acupuncture : In 1995, Li Zhi and Shan Jing published an article in the American Journal of Acupuncture (Vol. 23, No. 4), in which they conducted a study to clinically compare the efficacy of using scalp acupuncture combined with a single body acupoint with treatment by body acupoints alone for the treatment of sciatica. The experimental group received scalp acupuncture (Middle Line of Vertex and Lateral line 1 of Vertex) and body acupuncture (Yao San Dian) whereas the control group only received body acupuncture (GB30, BL36/50, BL40/54, GB34, BL57 and DU4). The results from this experiment showed that the effective rate for the experimental group was 91.67% and the effective rate for the control group was 66.67%. Therefore the results indicate that both scalp acupuncture combined with a single body point and body acupuncture alone were able to treat the symptoms of sciatica, but the effectiveness in the former group was significantly greater that that in the latter group.
  • Tui Na (Chinese Therapeutic Massage) :

The treatment principle of Tui Na in a sciatica patient is to move stagnation of qi and blood to stop the pain. In an anatomical perspective, the practitioner will use specific manipulations to release trigger points causing constriction on the sciatic nerve.

 

REFERENCES

http://acupuncture.com/Clinical/Sciatica.htm

http://h ome.revealed.net/jimchiro/backpain.html

http://www.ucdmc.ucdavis.edu/ucdhs/health/a-z/54Backpain/doc54mediaca l.html

http://www.spine-health.com

http://www.sciaticaclinic.com