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While few Doctors know about the spinal canal inflammatory disorder known as Arachnoiditis, Arachnoiditis itself is an old disease that was first discovered in the mid-1800’s. It was first written about in a book about railway injuries and was described as a syndrome of severe pain and neurological sequelae after railway accidents, a common trauma of the time. 


Further, tuberculosis and syphilis were known to cause a similar syndrome. Thanks to the discovery of antibiotics, and the decline of rail transport, these diseases were drastically reduced in the early 1900s. 


However, in the 20th century, several oil-based dyes were developed to help enhance x-ray imaging. In 1944, Pantopaque was introduced clinically for use in myelograms, a procedure where dyes were placed into the thecal sac in order to highlight the spinal cord and nerve roots.  (The thecal sac encapsulates the spinal cord and brain and contains the cerebrospinal fluid known as CSF). 

Although the Pantopaque dye was removed after a myelogram, residual Pantopaque droplets remained which irritated the nerves, and in an estimated 30 million cases, led to the development of Arachnoiditis. These irritated nerves from the spinal cord became inflamed and adhered to the thecal sac, usually in the arachnoid layer. This is the more severe form known as Adhesive Arachnoiditis (1)


Fast forward to the 21st century and you'll find that Arachnoiditis has made a significant comeback. New MRI technology has made it much easier to look at the spinal cord, thecal sac, (made of dura, arachnoid and pia meninges) and visualize the characteristic signs of nerve root adhesions and canal derangement.  Although still considered rare, it has re-emerged for a variety of reasons. There are several causes including aging, degenerative spine conditions, obesity, sedentary lifestyles, and invasive spine interventions and surgeries. It appears that a good portion of FBSS (Failed Back Surgery Syndrome) is actually Arachnoiditis. Failed interventional pain techniques such as epidural corticosteroid injections (ESI), including obstetrical epidural anesthesia are also modern causes of Arachnoiditis (2)



Anatomy of the spine
About Arachnoiditis


Arachnoiditis is initiated when there's an insult to the Arachnoid mater from either trauma, infection, chemical irritation, or substances foreign to the spinal canal, such as blood.


When there’s an assault (injury) to the Arachnoid meninge, the body's normal response is to trigger special glial cells located in the central nervous system. These then migrate to the injured area and release cytokines, which can be helpful at first and is part of the normal healing process. However, in those who are predisposed to Arachnoiditis, it also causes neuro-inflammation, which when left untreated, causes adhesions between the nerves and the thecal sac that surrounds the brain and spinal cord then become thick, swollen, and stuck together. This usually happens in the lower lumbar region of the spine where the spinal cord changes from one cord to a number of paired nerve roots that extend through the dura and innervate the muscles of the lower trunk, pelvic region, sexual organs and more. 


These adhesions become clumped and tethered which can progress to the scarring referred to as Adhesive Arachnoiditis (AA). Arachnoiditis (neuroinflammation of arachnoid meninge without adhesions/clumping) and Adhesive Arachnoiditis are the two most common forms, but there are also other more rare forms (3) 


Arachnoiditis is most commonly found in the lumbar region, but can also be found in the thoracic, cervical, optical, or intracranial region. Because much of Arachnoiditis is thought to be caused by repeated herniations and compression stenosis, it is most frequently found in the lumbar region. 


As a rarely diagnosed disease by doctors, Arachnoiditis is often missed for many years. Most rare diseases take on average 5.8 years and 7 doctors to be properly diagnosed.  It's unfortunate that most doctors do not know about Arachnoiditis, nor is it easy for the average physician to distinguish its characteristics on MRI.


It's very important that a proper diagnosis be made quickly after the original insult. If diagnosed and treated in the earliest inflammatory stage--aggressively treated with corticosteroids, along with strong anti-inflammatories such as Toradol--current research seem to indicate it can be put into remission. This is why we need to educate physicians and radiologists about the threat of Arachnoiditis and how to identify Arachnoiditis early on, rather than years later. Be sure to check out our Starting Point and Treatment Plan page to get started on a treatment plan.



Arachnoiditis is caused by inflammation of the arachnoid, one of the membranes surrounding and protecting the nerves of the spinal cord. It can result from spinal surgery, epidural injections, trauma to the spine, bacterial or viral infections affecting the spine, and exposure to certain chemicals. In some cases, it may also develop without a clear cause, making diagnosis and treatment challenging.


Arachnoiditis can cause a number of debilitating symptoms. The top ten symptoms as described by participants in our Stuff That Works survey are:


  1. Lower back pain

  2. Leg pain

  3. Pain

  4. Numbness

  5. Back pain

  6. Headache

  7. Odd sensations such as tingling, bugs crawling on legs, and water dripping on legs

  8. Muscle spasms

  9. Burning pain

  10. Weakness in legs 



Other symptoms can be tinnitus; problems with vision and hearing; bladder, bowel, or sexual dysfunction; hot/cold intolerance; stiffness; pain in next and between shoulder blades; and pain into hands. In severe cases, arachnoiditis may lead to paralysis of the legs.


Up until about 2015 there was little in the way of treatment options.  A few tactics were tried such as trying to remove the adhesions (thecaloscopy), antibiotic treatment, and a number of other miscellaneous treatments that had little success. Thecaloscopy has come some way since then and shows a bit of promise. Pentoxifylline/Vit E regimen for epidural fibrosis is a newer treatment, but it's expected to take a minimum of 4 years of constant use of these meds to show any improvement.  


Many in our community have been using the 3 Component Treatment Protocol by The Tennant Foundation, and anecdotal evidence from Arachnoiditis community members seem to show some clinical success, with reports of lowered pain and increased function. 


Unfortunately, this is what Arachnoiditis patients have to go through, just like many other rare disease warriors. We need to have Arachnoiditis recognized as the serious public health threat that it is and it's going to take a massive effort to get there. Most of the efforts that are being led, just like here at ACMCRN, are being accomplished by Arachnoiditis sufferers who face significant physical challenges in putting the time necessary to get Arachnoiditis studied.


Although there are other videos on learning to read your spinal MRI, I think this is a very good and easy to follow lecture on how to read your lumbar MRI by Dr. Gillard. It comes in both video and as an article.

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