Sciatic nerve pain, also called sciatica, is a neuropathic pain, which occurs when the sciatic nerve becomes inflamed. The classic clinical picture of sciatica is low back pain with radiation to one of the legs and can also be loss of sensation and muscle weakness in the affected limb.
What is the Sciatic Nerve?
The sciatic nerve arises from the junction of the nerve roots that grow between the fourth lumbar vertebra and the vertebral sacrum, giving rise to a thick nerve that descends towards the lower limb. The sciatic nerve is the longest nerve in our body, ranging from the lumbar spine to the feet, through the buttocks, thighs and legs. Along its path, several branches are released to innervate the structure of the lower extremities, such as muscles, joints and skin.
Root compression of a spinal nerve is called radiculopathy. Sciatica usually occurs due to the compression of one of its roots in the lumbar or sacral spine, being considered a lumbar radiculopathy. When a nerve is compressed, it swells and swells, causing pain along its path and, in some cases, loss of muscle strength and numbness in the affected area.
Causes of Sciatica:
The main cause of compression of the sciatic nerve and, consequently, of sciatica is a herniated disc in the lumbar spine. Other causes of compression of the sciatic nerve are spondylolisthesis (sliding of one vertebra over another), trauma, tumors or infections of the lumbar spine, stricture (narrowing) of the canal where the spinal cord passes, osteophytes (parrot beak) or osteoarthritis of the spine. Another possible cause of sciatic nerve pain is a condition called piriformis muscle syndrome. This problem occurs when the piriformis muscle in the gluteal region suffers a spasm and causes compression of the passes of the sciatic nerve below.
Main Risk Factors for the Development of a Sciatica:
–Age: elderly patients have a higher risk of degenerative spinal problems, which is much more common, the occurrence of herniated discs, parrot beak or osteoarthritis of the spine.
–Obesity: overweight, especially after long years, overloads the lumbar spine, favoring the appearance of lesions or anatomical changes in it.
–High: the type of professional occupation is also an important risk factor for sciatic nerve compression. People who work carrying a heavy load, who often have to push with their backs or spend long hours sitting or standing in the same position also exhibit a higher incidence of sciatica.
–Sedentary: sedentary lifestyle and lack of exercises for the muscles of the lumbar region also favor the appearance of the spine problems.
–Diabetes mellitus: diabetes is a disease that alone causes peripheral nerve injuries, and the sciatic nerve and its branches are one of those affected.
–Pregnancy: rapid weight gain, body changes and hormonal action, which causes relaxation of tendons and ligaments, can cause anatomical changes in the lumbar spine, favoring compression of the sciatic nerve.
Symptoms of Sciatic Nerve Pain:
When a nerve is compressed, it becomes inflamed, causing pain along its path and, in some cases, loss of muscle strength and tactile sensitivity.
Irradiation of Sciatica Pain:
In the specific case of sciatic nerve compression, the most common symptom is a backache that radiates unilaterally to the buttocks, the back of the side of the thigh, leg and foot. It is important to note that there is a sciatic nerve in each lower limb, but only one of them usually involves sciatica, causing pain occurs only in one of the legs. The intensity of pain varies greatly from case to case. It can be mild, causing only occasional discomfort or burning. In more severe cases, however, the pain can be unbearable, avoiding the patient to endure. An electric shock sensation is also common along the nerve path. Sciatica can get worse after exertion, cough or sneeze. Sitting for long hours also tends to worsen the symptoms of sciatica. Beyond pain, compression of the sciatic nerve can also cause numbness, tingling or reduction of muscle strength in the affected limb. In severe cases, the patient may present with urinary or fecal incontinence.
Diagnosis of Sciatica:
In many cases, sciatica is typical and complex tests are necessary for diagnosis. Supplementary exams are usually requested when the pain is very intense or when there is no improvement after the initial treatment. Studies of nerve conduction and electromyography can be useful when there is doubt about the diagnosis. Already imaging of tests such as MRI or CT scans are often used to identify the cause of sciatica, especially if it is caused by lesions such as herniated disc, narrowing of the spinal canal or tumors.
The initial treatment of sciatica is with medications to control pain, such as anti-inflammatory or analgesic. In many cases, the pain lasts a few days and disappears without any more aggressive behavior. In cases of severe pain, opioids (morphine derivatives) may be required. The use of muscle relaxant or benzodiazepines, such as diazepam, also helps control symptoms. Since sciatica pain is a pain of neurological origin, antidepressant or anticonvulsant medications can be used to control more chronic pain. In fact, a slight overload of activity in the spine seems to improve sciatica more than lying in bed. Swimming and physiotherapy usually have a good response. In some cases, acupuncture or magnetotherapy also shows good results. Depending on the cause or severity of sciatica, surgery to correct lumbar spine injuries is the only option for definitive pain control.