Is Sacroiliitis the Same Thing as Sciatica?

The main symptoms of sacroiliitis include a dull ache in the buttocks, lower back, and hip. ¹ Baronio M, Sadia H, Paolacci S, et al. Etiopathogenesis of sacroiliitis: implication for assessment and management. Korean J Pain. 2022;33(4):294-304. http://doi.org/10.3344/kjp.2020.33.4.294 ^{, 2} Buchanan BK, Varacallo M. Sacroiliitis. [Updated 2022 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448141/ In contrast, the main sciatica symptoms include sharp, shooting, or burning lower back pain, leg pain, and numbness or weakness in the affected leg. ³ Jensen RK, Kongsted A, Kjaer P, Koes B. Diagnosis and treatment of sciatica. BMJ. 2019;367:l6273. http://doi.org/10.1136/bmj.l6273

The underlying causes of sacroiliitis and sciatica are different

Both sacroiliitis and sciatica can cause symptoms in your buttocks, hip, and/or leg, but their underlying causes differ.

Sacroiliitis is a medical condition that causes inflammation in the sacroiliac joints, which connect the sacrum bone at the base of the spine to the hip bones. ² Buchanan BK, Varacallo M. Sacroiliitis. [Updated 2022 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448141/ The inflammation can cause pain in the lower back, buttocks, and legs.

Ankylosing spondylitis, a type of inflammatory arthritis, is the most common cause of sacroiliitis. Other causes may include acute or chronic trauma and infection of the SI joint. ¹ Baronio M, Sadia H, Paolacci S, et al. Etiopathogenesis of sacroiliitis: implication for assessment and management. Korean J Pain. 2022;33(4):294-304. http://doi.org/10.3344/kjp.2020.33.4.294

Sciatica is a set of symptoms that occurs when the sciatic nerve is irritated or compressed. The sciatic nerve is the largest in the body, spanning from the lower back to the feet. When the nerve gets compressed as it exits the lower spine, it can cause pain, numbness, and weakness in the areas it supplies, including the lower back, buttocks, and legs.

A lumbar herniated disc is the most common cause of sciatica. ⁴ Lu X, Chen L, Jiang C, Cao K, Gao Z, Wang Y. Microglia and macrophages contribute to the development and maintenance of sciatica in lumbar disc herniation. Pain. 2023;164(2):362-374. http://doi.org/10.1097/j.pain.0000000000002708 Other causes include spinal stenosis, degenerative disc disease, and spondylolisthesis. ³ Jensen RK, Kongsted A, Kjaer P, Koes B. Diagnosis and treatment of sciatica. BMJ. 2019;367:l6273. http://doi.org/10.1136/bmj.l6273

Read more about Sciatica Causes

Identifying the problem based on your symptoms

Several symptoms of sacroiliitis and sciatica overlap, and you may be confused about the actual source of your back and leg pain.

Here are a few unique pointers to help you understand where your pain may be originating from:

1. Areas affected by pain:
   • In sacroiliitis, lower back, buttock, and hip pain is typically more common than leg pain. ² Buchanan BK, Varacallo M. Sacroiliitis. [Updated 2022 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448141/
   • In sciatica, leg pain is usually greater than lower back pain, and the pain may radiate into your toes. The affected leg may also feel heavy. ⁵ Stynes S, Konstantinou K, Ogollah R, Hay EM, Dunn KM. Clinical diagnostic model for sciatica developed in primary care patients with low back-related leg pain. PLoS One. 2018;13(4):e0191852. http://doi.org/10.1371/journal.pone.0191852
2. Intensity of pain:
   • In sacroiliitis, the pain is usually a dull ache that increases when sitting for long periods and/or during activities that involve bending or twisting the hip. ¹ Baronio M, Sadia H, Paolacci S, et al. Etiopathogenesis of sacroiliitis: implication for assessment and management. Korean J Pain. 2022;33(4):294-304. http://doi.org/10.3344/kjp.2020.33.4.294
   • In sciatica, the pain is usually described as sharp, shooting, or burning. ⁴ Lu X, Chen L, Jiang C, Cao K, Gao Z, Wang Y. Microglia and macrophages contribute to the development and maintenance of sciatica in lumbar disc herniation. Pain. 2023;164(2):362-374. http://doi.org/10.1097/j.pain.0000000000002708
3. Altered sensation:
   • Sacroiliitis can cause stiffness and swelling in the lower back and buttock region.
   • Sciatica often results in numbness, tingling, or weakness in the affected leg. ² Buchanan BK, Varacallo M. Sacroiliitis. [Updated 2022 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448141/ ^{, 4} Lu X, Chen L, Jiang C, Cao K, Gao Z, Wang Y. Microglia and macrophages contribute to the development and maintenance of sciatica in lumbar disc herniation. Pain. 2023;164(2):362-374. http://doi.org/10.1097/j.pain.0000000000002708

While these are relatively common pain patterns, some people may experience other symptoms specific to the underlying cause of their pain.

Treatment options vary for sacroiliitis and sciatica

Successful low back pain treatment depends on addressing the underlying cause of inflammation or irritation to the joints, nerves, and other tissues in the lower back.

• Sacroiliitis treatment focuses on reducing pain and inflammation, improving joint function, and preventing further damage to the SI joint. ² Buchanan BK, Varacallo M. Sacroiliitis. [Updated 2022 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448141/

• Sciatica treatments can vary and primarily focus on managing the underlying cause of sciatic nerve root compression. ⁴ Lu X, Chen L, Jiang C, Cao K, Gao Z, Wang Y. Microglia and macrophages contribute to the development and maintenance of sciatica in lumbar disc herniation. Pain. 2023;164(2):362-374. http://doi.org/10.1097/j.pain.0000000000002708

A physician trained in treating musculoskeletal conditions can accurately diagnose the underlying cause of your pain and formulate an effective treatment plan.

Learn more:

Is My Pain Sciatica or Something Else?

Sacroiliac Joint Dysfunction Symptoms and Causes