What is posttraumatic tethered spinal cord and what symptoms can it cause?

A posttraumatic tethered spinal cord occurs after a spinal cord injury (SCI) when scar tissue forms between the spinal cord and the lining of the spinal canal around it. This places the spinal cord on an abnormal stretch, reducing the spinal cord’s normal mobility within the spinal canal. Additionally, the spinal cord normally moves with cerebrospinal fluid (CSF) flow, and the tethering will impede this normal flow around the spinal cord. Together, the stretch on the cord and impaired flow can cause the spinal cord to stop functioning optimally and even deteriorate. If tethering becomes symptomatic, people may develop changes such as worsening neuropathic pain, sensory loss, weakness, spasticity, autonomic dysreflexia/abnormal sweating or bladder/bowel and respiratory problems.

Key takeaways

• Posttraumatic tethered spinal cord happens after a spinal cord injury when scar tissue forms between the injured spinal cord and the lining of the spinal canal around it, reducing the cord’s normal mobility within the spinal canal and the spinal fluid flow dynamic.
• The spinal cord has a normal degree of stretch it can tolerate with normal body movements; tethering can create additional abnormal stretch on neural tissue, which can be detrimental.
• Tethering can also disrupt normal spinal fluid flow around the spinal cord, altering pressure dynamics, which can also be detrimental.
• All people with spinal cord injury have some degree of tethering, but it does not always cause symptoms.
• Symptoms that raise concern are typically progressive (trending worse over time), including new or worsening neuropathic pain, sensory loss, weakness, spasticity, autonomic dysreflexia/abnormal sweating, and bladder, bowel and respiratory changes.
• Symptoms from tethering can appear months to decades after injury, so new symptoms after SCI still deserve evaluation.

After SCI, why “new symptoms later” matter

After a spinal cord injury (SCI), you get to know your “new normal.” Many people recover and stabilize over about six to 12 months, settling into a baseline for strength, sensation, spasticity, bladder routines, blood pressure control, pain and even sweating patterns.

So, when things change later — new pain, worsening tingling, stronger spasms, new bladder issues, loss of feeling and/or strength, or increased intensity of dysautonomia symptoms (i.e., abnormal sweating or autonomic dysreflexia (sudden “wild” blood pressure swings)) — it’s reasonable to ask ‘is something else wrong?’.

One possible cause is a posttraumatic tethered spinal cord.

What tethering means

After a spinal cord injury, scar tissue will form. Over time, that scarring creates fibrous bands that attach the surface of the spinal cord and nearby nerve rootlets to the lining of the spinal canal (the dura).

Normally, the spinal cord has mobility within the spinal canal and moves with the flow of spinal fluid and with everyday motion like bending and twisting. When scar tissue anchors the spinal cord, it can reduce mobility and create abnormal stretch of the neural tissue.

“An uninjured spinal cord has a degree of mobility it can tolerate with normal body movements and normal spinal fluid flow,” says Scott P. Falci, MD, a neurosurgeon at the HCA HealthONE Falci Institute for Spinal Cord Injuries in Englewood, CO. “Tethering reduces that mobility and can create abnormal stretch on the neural tissue and impede normal spinal fluid flow, which may contribute to worsening symptoms.”

Important nuance: Nearly everyone with a permanent spinal cord injury has some degree of tethering. That does not always cause a problem. The concern is when the tethering becomes symptomatic and symptoms progress over time.

Why tethering can cause symptoms

Two big concerns are often discussed:

1. Abnormal stretch on neural tissue: The spinal cord has a degree of elasticity, and nerve pathways can tolerate a small amount of movement and stretch. When scarring limits spinal cord mobility, everyday motion may create abnormal stretch that impairs the function of neural elements and can reduce how well nerve pathways function.
2. Disrupted CSF flow and pressure changes: CSF is constantly produced by the brain and circulates around the cord. Scarring can subtly disrupt the flow, contributing to stress on the cord.

When tethering can show up

Posttraumatic tethering symptoms can show up as early as two months after injury or decades later (even 40 years after injury, Dr. Falci explains!). That long timeline is one reason people don’t always connect the new symptoms to an old injury.

Tethering also isn’t always obvious on MRI. Even if the cord looks relatively centered, it may still be functionally tethered. Therefore, imaging is interpreted in context, not isolation.

Symptoms: What you may notice

Symptoms can look different for everyone, but the pattern is often the same: things slowly shift instead of staying stable.

Common symptoms of posttraumatic spinal cord tethering:

• Sensory changes: new numbness, reduced skin feeling, painful touch or sensation that is “off”
• Motor changes: losing strength you had regained, more difficulty with feeding self or grasping objects, difficulty with transfers, new walking problems (if you walk), more tripping, or weakness that is clearly new
• Pain changes: pain you have never had before or pain you have always had that is now more intense; specifically neuropathic pain (for example: burning, sharp, electric, pins and needles) felt in parts of the body with lost or impaired sensory function
• Spasticity and tone changes: tighter muscles, harder to manage spasms, stiffness, reduced flexibility
• Bladder and bowel changes: new urgency, trouble emptying, incontinence, or changes in bowel routines

“The biggest clue is change over time,” Dr. Falci adds. “If symptoms are new or trending worse, it is worth talking to an expert.”

What to do if this sounds familiar

If you notice progressive changes such as sensory loss, strength loss, worsening neuropathic pain, increasing spasticity, autonomic dysreflexia, or bladder/bowel changes, bring it up with your spinal cord injury team. Tethering is one possible explanation, but other causes can look similar, and a clinician will help sort out the pattern.