What Triggers Sciatica?

Sciatica refers to the shooting pain and/or burning sensation that radiates along the path of the sciatic nerve. It often causes pain and other associated symptoms in the hips, buttocks, thighs, calves, and ankles. There are multiple causes of sciatica – the common ones include a bone spur, a herniated disc, narrowing of the spine, or a pinched nerve – all of which leads to inflammation, pain, burning, tingling sensations, and even numbness.

Spinal radiculopathy (pinching of spinal nerves) due to different medical conditions is the leading trigger of sciatica. Besides radiculopathy, there are several triggers that can initiate or exacerbate the sciatic nerve compression – leading to sciatica. These include;

Triggers Of Sciatica

Sciatica itself is not a disease – but a common symptom of different underlying medical or surgical conditions. Based on the statistical data, following are some of the most common triggers of sciatica.

Herniated Discs

Disc herniation or commonly known as bulging of the discs occurs when the nucleus (inner part of the disc) breaks through the annulus fibrosus (outer part). This leads to pressing of the disc material against an adjacent nerve root. If disc herniation occurs in the lumbar or sacral region (from where the sciatic nerve emerges), it causes compression of the sciatic nerve and leads to sciatica.

Most of the time, this nerve compression occurs on only one side – developing sciatica symptoms on only the respective side (leg). Rarely, it may put pressure on both sides of the sciatic nerve and cause the development of bilateral sciatica (shooting pain and burning on both sides of the legs). Statistics have shown that disc herniation is one of the most common triggers of sciatica – especially in older people.

Chemical Inflammation

This condition is also related to disc herniation. A herniated disc doesn’t only cause direct compression of the sciatic nerve, but also causes chemical inflammation. The nucleus of the disc (soft inner layer) is mostly collagen and water, but also contains some powerful chemicals that when punched through the annulus cause inflammation and swelling of the sciatic nerve.

Chemical inflammation of the sciatic nerve is usually a complication of disc herniation and exacerbates the symptoms of sciatica.

Disc Degeneration

Degenerative disc disease (DDD) or disc degeneration is a common risk factor for herniated discs – the most common cause of sciatica.

Disc degeneration is common in the elderly and its incidence increases with increasing age. This inevitable part of aging causes wearing and tearing of intervertebral discs through a drying out process called disc desiccation. This process doesn’t happen in days, rather causes a slow degeneration over the years and decades. It causes the water content in the nucleus to dry out – leading to brittle and weaker discs. Such discs are more prone to trauma and herniation and can also trigger sciatica.

Stenosis

Neural foramina are the thin passageways made of bones and ligaments that provide exit pathways to the spinal nerves. After emerging from the spinal cord, nerve roots of the spinal nerves pass through these openings, join with each other, and provide the nerve supply to the different parts and organs of the body.

Stenosis or narrowing of these openings (neural foramina) puts pressure on the nerves and cause nerve pinching and irritation. Stenosis of the lower lumbar (L4, L5) or upper sacral (S1, S2, S3) causes spinal radiculopathy and leads to sciatica.