Adhesive arachnoiditis: 10 keys to diagnosis & treatment

Adhesive arachnoiditis is inflammation of the membranes covering the spinal cord and nerve roots. It can form internal scarring that makes roots “stick” together, causing chronic pain, tingling, weakness and, in some cases, bladder or bowel problems. There is no simple cure, but there is a rigorous diagnostic path and options to improve pain and function. This guide helps you recognize warning signs, useful tests, therapeutic alternatives, and when to seek urgent care.

• Not all sciatica-like low back pain is the same: adhesive arachnoiditis has its own clinical and imaging clues.
• MRI is key; in borderline cases, a prone MRI can add useful information.
• Treatment is usually multimodal and non-surgical; surgery is reserved for very selected situations.
• Red flags requiring urgent assessment: sudden loss of strength, fever, new incontinence, rapidly worsening pain.

What is adhesive arachnoiditis?

Arachnoiditis is inflammation of the arachnoid, one of the meninges that protect the spinal cord and nerve roots. In its “adhesive” form, that inflammation leaves internal scars that adhere roots to each other or to the dural sac wall. This “stickiness” prevents nerves from gliding normally and promotes persistent pain—often burning—with paresthesias and cramps. It shares features with radiculopathy, stenosis, or so-called failed back surgery syndrome, which explains delayed diagnoses if it is not considered.

Symptoms and signals that should raise suspicion

• Low back pain radiating to buttocks or legs, burning or electric-shock like.
• Tingling or pins-and-needles in the legs.
• Muscle spasms and nocturnal cramps.
• Weakness or a sense that the leg “gives way,” with tripping or unsteady gait.
• Sphincter dysfunction (urinary urgency, leakage, constipation), especially if new.
• Worsening with sustained postures or efforts that tension the roots.

Red flags (go to urgent care): fever with vertebral pain, sudden loss of strength, saddle anesthesia, new incontinence, pain that worsens day by day despite analgesia.

Causes and risk factors

Adhesive arachnoiditis may be associated with different settings. None alone guarantees the disease; what matters is the combination of clinical context and imaging findings.

• Prior spinal interventions or neuraxial procedures (especially if multiple).
• Meningeal or epidural infections.
• Spinal trauma.
• Degenerative processes (stenosis, chronic herniation).
• Historical chemical irritants (e.g., certain old myelographic contrasts).
• Inflammatory/immune milieu in some people.

How is it diagnosed?

History and neurological examination

Assess pain distribution, strength, reflexes and sensation (including perineal area if appropriate), gait, and effort tolerance. Review surgical history and onset circumstances.

Magnetic resonance imaging (MRI)

MRI is the key test. In advanced stages you may see root clumping, reduced CSF flow, or the “empty sac” sign with roots plastered to the periphery. If supine MRI is equivocal but clinical suspicion is high, some centers consider a prone MRI to reveal subtle adhesions or CSF blockages.

Differential diagnosis

• Radiculopathies due to herniation or stenosis.
• Post-surgical arachnoiditis vs epidural fibrosis (scar outside the dura).
• Syringomyelia, tethered cord, focal arachnoiditis with cysts.
• Peripheral neuropathies, facet-mediated pain, and myofascial syndromes.

What treatment options exist

1) Pharmacological management (always supervised)

• Neuropathic pain modulators with individualized regimens.
• Conventional analgesics; opioids are reserved for refractory cases and short periods.
• Corticosteroids in very specific scenarios; not a chronic solution.

2) Rehabilitation and self-care

• Tailored, progressive exercise: walking, stationary cycling, or aquatherapy, titrated to pain.
• Postural and motor-control work (pelvic girdle, glutes, core).
• Sleep hygiene and joint protection (avoid sustained postures, take micro-breaks).
• Psychological support and pain education to reduce disability and catastrophizing.

3) Selected interventional procedures

• Spinal cord stimulation (SCS) or peripheral field stimulation for refractory neuropathic pain.
• Diagnostic/therapeutic blocks in well-indicated cases.

4) What about surgery?

Surgery is not the usual route in diffuse arachnoiditis. In highly selected cases, microsurgical adhesiolysis, duraplasty, or shunting may be considered when there is CSF blockage or cysts. It is essential to weigh the risk of new scarring and align expectations: the aim is typically to improve pain or function, not to “cure” the disease.

Expected benefits vs risks and limitations

• Potential benefits: pain reduction, improved exercise tolerance and sleep, greater daily autonomy.
• Risks/limitations: heterogeneous response, medication side effects, device failure, re-formation of adhesions after surgery, emotional impact of chronic pain.

Individualizing the plan and periodic follow-up improve the likelihood of good outcomes.

Practical criteria for referral to a specialized unit

• Severe, persistent neuropathic pain unresponsive to conservative measures.
• Ongoing diagnostic uncertainty (clinical–imaging discordance).
• Progressive neurological deficits or sphincter dysfunction.
• Multiple surgical histories with functional decline.
• Need for advanced techniques (e.g., targeted MRI, neuromodulation).

Realistic recovery timelines

There is no single timetable. With a multimodal plan, many people report gradual improvements over weeks to months as medication, exercise, and sleep routines are adjusted. Sustained habits (regular physical activity, postural hygiene, psychological support) help maintain results in the medium term.

When to seek urgent care?

• High fever with vertebral pain.
• Sudden loss of strength in one or both legs.
• Saddle anesthesia or new-onset incontinence.
• Pain that worsens day by day despite analgesia and relative rest.

Myths and realities

• “MRI sees everything.” Not always: some cases are subtle; clinical judgment prevails and complementary techniques exist.
• “If I have surgery, it’s cured.” Not exactly: even in surgical candidates, the goal is relief; responses vary.
• “If it hurts, I must rest.” Prolonged rest usually deconditions; graded activity is better.
• “It’s all psychological.” False: the pain is real. Emotions modulate the experience but do not cause it by themselves.

Frequently asked questions

How is adhesive arachnoiditis diagnosed?

With a thorough history and neurological exam, and MRI. In doubtful cases, a prone MRI and neurophysiological studies may be considered.

Does adhesive arachnoiditis have a cure?

There is no simple cure. The goal is to reduce pain and improve function with an individualized multimodal plan; surgery is reserved for selected cases.

What most commonly causes it?

It may be related to previous surgeries, infections, trauma, degenerative processes, or historical chemical irritants. Not all cases share the same cause.

How does it differ from epidural fibrosis?

Epidural fibrosis is scarring outside the dura; adhesive arachnoiditis affects membranes and roots within the thecal sac. MRI helps differentiate them.

When to consider spinal cord stimulation?

For refractory neuropathic pain after optimizing medication, rehabilitation, and less invasive procedures, and always after evaluation in a specialized unit.

Which signs require urgent care?

Fever with vertebral pain, sudden weakness, saddle anesthesia, new incontinence, or pain that worsens day by day despite analgesia.

Which exercises are usually safest at the start?

Gentle, progressive aerobic activity (walking, stationary cycling, aquatherapy), postural and motor-control work, according to tolerance and supervision.

How long until improvement is noticeable?

It is usually gradual over weeks or months with a multimodal plan. Timelines vary; consistency and therapeutic adjustment are decisive.

Glossary

Arachnoid: Middle meningeal layer covering the spinal cord and nerve roots.

Adhesions: Bands or areas of internal scar that “stick” tissues that should glide.

CSF: Cerebrospinal fluid, the fluid that circulates around the brain and spinal cord.

Root clumping: Abnormal clustering of nerve roots visible on MRI.

Neuromodulation: Techniques that modify pain perception using implantable electrical devices.

Important notice

This content is informational and does not replace individual medical evaluation. Do not start, modify, or stop treatments without professional advice.