Sciatica is a common and often disabling condition. 1-5% of people suffer from this annually, and it will occur in 15-40% of people in their lifetime. It is rare under the age of 20, most common in the 5th decade and affects both men and women equally. The term sciatica is often over used, to describe any type of pain that occurs in the back, buttock or leg, however the true definition of sciatica is, an irritation of the sciatic nerve or its nerve roots.
The sciatic nerve is a peripheral nerve that arises from the L4 to S3 nerve roots. It runs through the lower back, pelvis, buttock and into the back of the thigh. Sciatic pain is commonly caused by a lumbar disc injury, causing compression or chemical inflammation which irritates the nerve roots. The L4/L5 and L5/S1 discs are the most commonly affected levels of the lumbar spine. Mechanical compression causing irritation of the sciatic nerve can also occur anywhere along its pathway. Other potential sites of nerve compression are in the pelvis, gluteal muscles and upper hamstring. It is important to note there are other causes of buttock and leg pain that may resemble sciatica. These include lumbar referred pain, hip joint pathology or sacroiliac joint dysfunction.
Symptoms of sciatica include pain radiating into the buttock, back of the thigh, calf, outside of the shin and into the foot. In more severe cases, there may also be some numbness or tingling. Pain is often aggravated by sitting, bending, coughing, sneezing or lifting. A detailed assessment will include a full neurological examination of lower limb sensation, reflexes and strength as well as signs of increased tension and pressure on the nerve. Lumbar spine movements may be restricted and may reproduce leg pain however palpation of the lumbar spine may not reveal much abnormality. A thorough examination should also include the hip joint, gluteal and hamstring tendons and muscles as well as the sacroiliac joint, to rule them out as a potential cause of the pain.
The prognosis with conservative treatment is normally good, so initial scans are not usually warranted. Imaging may be required if symptoms are not settling or there is worsening neurological function. MRI scanning is the gold standard, but a CT scan can also be used.
The pain from sciatica, in 80-90% of patients, will settle within a 3 month period with conservative therapy alone. This may include anti-inflammatory medications, physiotherapy and avoiding aggravating activities such as lifting, bending forward and prolonged sitting. Physiotherapy is guided by the exact cause of the irritation, but will generally be a combination of manual or ‘hands on’ therapy and exercises including core strengthening. If symptoms are not settling then other treatments may be required such as nerve root injection. In a very small number of cases, where significant structural change has taken place in the spine, conservative management may not be enough to free the nerve up and surgery to decompress may be indicated.
Article by Philip Ting