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What is arachnoiditis?

Arachnoiditis is a disorder caused by the inflammation of the arachnoid. The arachnoid is one of the membranes that surround and protect the nerves of the spinal cord. The arachnoid can become inflamed because of:

  • An irritation from chemicals
  • Infection from bacteria or viruses
  • Direct injury to the spine
  • Chronic compression of spinal nerves
  • Complications from spinal surgery or other invasive spinal procedures (procedures that involve breaking the skin)

Inflammation can sometimes lead to scar tissue or scar adhesions, which cause the spinal nerves to “stick” together.

If arachnoiditis begins to interfere with the function of one or more of the spinal nerves, it can cause a number of symptoms, including chronic and persistent pain, numbness, tingling, and a characteristic stinging and burning pain in the lower back or legs. 

Some people with arachnoiditis will have debilitating muscle cramps, twitches, or spasms.  It may also affect bladder, bowel, and sexual function. In serious cases, arachnoiditis may cause the lower limbs to be paralyzed.

Arachnoiditis remains a difficult condition to treat, and long-term outcomes are unpredictable. Most treatments focus on relieving chronic pain and improving symptoms that affect a person's daily functioning. 

Doctors often recommend a combination of pain management, physical therapy, exercise, and psychotherapy (talk therapy).  Results of surgery for arachnoiditis are generally poor and give only short-term relief.

Learn About Clinical Trials
Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one improve care for people with arachnoiditis?

Consider participating in a clinical trial so clinicians and scientists can learn more about arachnoiditis and related disorders.  Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with arachnoiditis at

Where can I find more information about arachnoiditis?

Information on arachnoiditis may be available from the following organization:

American Chronic Pain Association
Phone: 916-632-0922 or 800-533-3231

Learn about related topics

Order publications from the NINDS Catalog
The NINDS Publication Catalog offers printed materials on neurological disorders for patients, health professionals, and the general public. All materials are free of charge, and a downloadable PDF version is also available for most publications.