How is a posttraumatic tethered spinal cord diagnosed?

Quick answer: Diagnosing a posttraumatic tethered spinal cord is usually pattern-based, not a single test. Clinicians look for progressive changes after spinal cord injury, such as worsening neuropathic pain, sensory loss, weakness, spasticity, autonomic dysreflexia/abnormal sweating, or bladder/bowel changes, then confirm the pattern with a neurologic exam and imaging (often MRI, sometimes CT myelography). Just as important, they rule out other causes that can mimic the symptoms of tethering, including spinal stenosis, new disc compression, tumors, vascular malformations, spinal instability, and some neurologic diseases.

Key takeaways

• Diagnosis is pattern-based: symptoms over time with neurologic exam and imaging.
• Doctors must rule out other causes (stenosis, disc compression, tumors, vascular malformations, spinal instability, and some neurologic diseases).
• MRI is common, but tethering can be subtle. Imaging is interpreted alongside your symptoms and exam.

What doctors mean by “posttraumatic tethered spinal cord”

After a spinal cord injury, scar tissue can form between the spinal cord and its coverings (the dura), therefore tethering the spinal cord to its coverings. Over time this scarring may reduce the cord’s normal mobility within the spinal canal. Normally, the cord moves with cerebrospinal fluid (CSF) flow and with everyday motion like flexion and extension. When scarring anchors the cord, it can create abnormal stretch to the cord, causing a degree of injury to the cord itself, which can contribute to symptoms.

When to consider tethering as a possibility

Many people with SCI have a baseline that stabilizes over months. Concern arises when a progressive worsening of symptoms ensues.

Common red-flag patterns include:

• New or worsening neuropathic pain (burning, sharp, electric)
• New sensory loss or less feeling on the skin
• Losing strength and function you had regained
• Worsening spasticity or tone
• Changes in bladder or bowel function
• Worsening dysautonomia, including more frequent or more severe autonomic dysreflexia episodes or abnormal sweating

How diagnosis happens (step by step)

1. Clinical history: what has changed and how it is trending

This is the foundation. Your team will ask what has changed, when it started and whether it is stable or progressing. They’ll look for a consistent story across pain, sensation, strength, spasticity, dysautonomia and bladder/bowel function. “The story matters,” says Scott P. Falci, MD, a neurosurgeon at the HCA HealthONE Falci Institute for Spinal Cord Injuries in Englewood, CO. “When someone tells me, ‘This is not how I usually feel,’ that is important.”

2. Neurologic exam: compared to your baseline

Next comes a detailed assessment of clinical history as well as assessment of:

• Strength/coordination
• Sensation
• Reflexes, spasticity and tone
• Functional abilities (walking, transfers, hand function, endurance)

If you have older clinic notes, rehab notes, prior exams, it is helpful to compare these to your current presentation.

3. Imaging within context

MRI is often the main test because it can show the spinal cord, scarring, and related problems, including a syrinx, which is a fluid-filled cavity that can form in the cord after injury. If MRI is not an option for you, your team may recommend another approach, such as CT myelography, depending on your situation. Important to note: tethering can be subtle on imaging so even if the cord appears relatively centered, it may still have reduced mobility due to scarring. Imaging findings are always interpreted in context.

4. Rule out other causes

Symptoms that look like tethering can also come from conditions unrelated to tethering. Before deciding tethering is the explanation, your team will commonly look for:

• Spinal stenosis
• New disc compression or herniation
• Tumors in the area
• Vascular malformations
• Spinal instability
• Other neurologic causes (e.g., MS, ALS)

“We do not diagnose tethering from one clue,” Dr. Falci says. “We look for a pattern across symptoms, exam findings, imaging and other diagnostic testing.”