What is sciatic nerve pain?
Sciatic nerve pain, or Sciatica is a common type of pain affecting your sciatic nerve. Sciatica is the name given to any sort of pain caused by irritation or compression of your sciatic nerve. The sciatic nerve is the longest nerve in the body. It runs from the back of your pelvis, through the buttocks, and all the way down both legs ending at the feet.
What are the symptoms of sciatic nerve pain?
Note that when your sciatic nerve is compressed or irritated, it can cause you pain, numbness, and/or a tingling sensation that radiates from your lower back down one or both legs, sometimes as far as the foot and toes.
What causes the pain/discomfort?
As a result of sciatica, discomfort can range from mild to very severe. It can also be diagnosed from acute to chronic depending on the severity of the issue. It can be caused by lumbar spinal stenosis, degenerative disc disease (DDD), a slipped disc, muscle strain, a repetitive strain injury, and other risk factors. The most common risk factor is increased pressure and force on the spine. Consequently, those who are pregnant, overweight, have improper posture, sit for long periods, or have a very physically demanding job are more at risk to develop sciatic pain due to the increased load on the spine.
Ergonomics and Sciatic nerve pain
Ergonomics is the study of the body at work. In some cases, your sciatic pain is caused by a task or position at work, and other times it is caused by a risk factor as mentioned above which may be aggravated by factors present in your workplace. From an ergonomic position, it is important to evaluate the three major risk factors; Force, Repetition, and Posture:
The meaning of force is the amount of pressure and load of your spine during certain positions. It is lowest in the supine position and highest in a bent over position. Sitting has a higher force than standing, and sitting while leaning forward has a higher force than sitting straight up. Sitting was shown to be a risk factor in the development of low back pain (Magora, 1972); reported to cause compression of the sciatic nerve (Deverell et al., 1968; Aguayo, 1975); and foot swelling (Winkel et al., 1988).
It is noteworthy that sitting without a back support vs sitting in a seat equipped with lumbar support has been shown to reduce the stress on the lumbar spine in biomechanical studies (Andersson et al., 1974a; Andersson et al., 1974b). Proper chair lumbar support and upper back support is very important. Lumbar support should be positioned in the curve of your low back to allow your spine to maintain its neutral position. It is also recommended to stand and move often throughout the day to decrease the load and force on your spine.
Standing workstations are also beneficial in reducing the force on your spine in severe cases of sciatic nerve pain. When standing, it is important that you hold a neutral posture with your arms relaxed at a 90-degree position. It is recommended to stand with your feet hip width apart and avoid locking your knees or leaning into your hip, as this can increase tension in your hip and knee joints.
Furthermore, it is also essential not to stand or sit for too long, as in either position your muscles will become fatigued. Alternating from sitting and standing frequently every 30-45 minutes throughout the day will also reduce force, muscle fatigue, and decrease sciatic symptoms.
Repetitive tasks are very common in the workplace. The most common in office settings are leaning forward towards the computer screen, bending over reading material as well as reaching and twisting while performing daily tasks. Awkward postures also contribute to sciatic nerve pain as when used repetitively or for prolonged periods, result in increased risk of fatigue, pain, or injury.
These postures are sustained either actively by muscle contractions, or passively by compressive or tensile loads on bones, muscles, tendons, ligaments, etc. (Chaffin et al., 1984). Leaning, twisting, bending and reaching can all be categorized as awkward postures and can lead to increased muscle strain and compression on the sciatic nerve. It is important to keep equipment within your arm’s reach and to move your entire body towards the task rather than twisting at the trunk.
Proper posture is essential to help reduce your muscle fatigue. An easy tip to follow is to maintain the 90-degree rule. Your shoulders should be relaxed and not elevated. Elbows should be at 90 degrees and resting comfortably on the armrests. Wrists should be in a straight and neutral position. Your back should be straight and well supported by your chair’s backrest; there should be no space between your chair and your back; the lumbar support should be supporting the curve in your low back. Your hips and legs should be in a straight line with the knees at a 90-degree position. For circulation purposes, there should be some room between the back of your knees and the chair.
If the chair seat is too long it will cause discomfort in your legs, will not provide sufficient back support and will decrease leg circulation. If the chair is too short, there will be inadequate support for your legs, increasing pressure on the knees. The chair width and armrest width is also very important. If the chair is too wide, your body will favour one side vs the other and increase the pressure and load into one side of the back and hip. If the chair is too narrow, the armrest may be adding pressure and irritating your thigh and hip. The chair must also be placed at the proper height to allow your hips and knees to be at the same level and for the feet to be placed flat on the floor to reduce any added pressure.
It is also relevant that footrests are very useful to help keep a proper posture as they allow the feet held at an elevated position in the event the feet do not reach the floor. However, improper use of a footrest may raise your knees higher than the hip and thus increase back and sciatic problem.
In summary, it is necessary to re-evaluate your everyday day tasks and postures to assess the strains and discomforts that may be affecting your body. An ergonomic assessment would be beneficial, as the regulated health professional will evaluate your workstation to assess the risks, provide education regarding proper positioning and behaviours, as well as provide appropriate recommendations specific to your needs. Finally, if you believe you have or may be feeling signs of sciatic nerve pain, it is strongly recommended that you consult your family physician to determine a treatment plan tailored to your needs.
Chaffin, D.B., 1973. Localized muscle fatigue – Definition and measurement. Journal of Occupational Medicine, 15(4): 346-354.
Chaffin, D.B. and Andersson, G.B.J., 1984. Occupational Biomechanics. John Wiley & Sons, New York. Coffman, J.D., 1975. Diseases of the peripheral veins. In: P.B. Beeson and W. McDermott (Eds.), Textbook of Medicine Vol. II, 14th edition. W.B. Saunders Co., Philadelphia, pp. 1083-1084.
Deverell, W.F. and Ferguson, J.H., 1968. An unusual case of sciatic nerve paralysis. The Journal of the American Medical Association, 205(10): 109-110.
Magora, A., 1972. Investigation of the relation between low back pain and occupation 3. Physical requirements: Sitting, standing and weight lifting. Industrial Medicine, 41(12): 5-9.
Winkel, J., Jorgensen, K. and Noddeland, H., 1988. Significance of ambient temperature for foot swelling and oedema-preventing effect of modest leg activity while seated. In: A.S. Adams, R.R. Hall, B.J. McPhee and M.S. Oxenburgh (Eds.), Ergonomics International 88. Taylor & Francis, London, pp. 140-142.[:]