Sciatica results from a structure impinging on a lumbar nerve root, causing compression and/or inflammation enough to cause neurological changes in the skin, reflexes and muscles served by the affected nerve. Not a common syndrome, it is estimated that 3-5% of the population suffer this kind of problem at some time. It affects men and women equally with men most susceptible in their forties and women in their fifties. Up to a quarter have symptoms which last more than six weeks and referral to physiotherapists for acute management is routine.

When the intervertebral disc material prolapses it causes injury by two mechanisms: direct mechanical compression of the nerve and chemical irritation. The disc material should not be outside the disc and its toxic chemicals help swelling both of the nerve and its surrounding structures, resulting in blockage of the circulation and of the nerve’s normal message conduction. While the prolapse is responsible for the sciatica it has not been shown that the bigger the prolapse the more severe the person’s pain.

The lumbar discs are more likely to have prolapses due to the high levels of force they have to endure. When we lift things away from the body, bend over at the waist or perform standing activities the back has to cope with the leverage involved. When stresses are loaded onto the discs the hydraulic mechanism magnifies the forces on the outer walls by three to five times that which the skeleton has to cope with. With time these stresses cause failure of the outer disc material and allow prolapses to occur.

Patients report that the onset of sciatica is rapid and accompanied by back pain, although pre-existing back pain may ease when the leg pain starts. Worse with coughing, sneezing and sitting down, the pain is better standing up or lying flat. Typical pain distribution is through the buttock then down the back of the leg to the ankle and foot or down the side instead. Sciatica does occur in disc levels L1 to L3 but only in for five percent of cases, the pain being in the front of the thigh and not in the lower leg. Some patients present with individual areas of pain rather than the whole picture.

The physiotherapist will take the patient’s history with particular attention to “red flags” which are indicators of a serious medical reason for the back pain and the patient will not be appropriate for physio. Weight loss, fever, night sweats, age (under 20 or over 55), problems with bladder and bowel control, serious past medical history and night pain will be noted. Any uncertainty means referral to a doctor for investigation. The physio will note any postural abnormalities and the nature, position and activity response of the pain symptoms.

The physiotherapist begins with postural observation of the patient which can show an inability to stand up or a thoracic shift to one side. Spinal movements are performed and the pattern of movement limitation noted, with a full neurological examination of the lower limbs. The physio is looking for deficits in muscle power, reflexes or feeling which are related to the specific nerve root involved. The straight leg raise may be performed to check the stretch reaction of the spinal nerve.

The McKenzie technique works on pain centralisation, the tendency for pain to move towards the back from the legs, suggesting a disc problem, and many physios use this technique. Pain in the front of the thigh and over the knee can be referred from the hip joint, so the physiotherapist will assess the lower limb joints to check the diagnosis. A thorough examination informs the physiotherapist of the likely diagnosis and how they might treat the syndrome, or that the patient needs to be referred to a medical practitioner for a consultation and investigation.

Physiotherapists use a variety of therapies to treat sciatica, with McKenzie technique being a mainstream technique for discogenic pains. Mobilisation and manipulation techniques, core stability work, myofascial release, specific exercises, manual techniques, soft tissue work and massage, analgesia, patient education, rest, the best position to relieve extreme sciatica pain and advice are all used as treatments. Most sufferers settle without investigation or surgery and a long term exercise programme is useful once the problem has settled.