Can You Get an MRI with Harrington Rods?

Most people with Harrington rods can safely undergo an MRI, though the scan requires some extra planning. The original Harrington rod, a stainless-steel spinal implant used from the 1960s through the 1990s, is no longer implanted today but remains inside hundreds of thousands of people who had scoliosis surgery decades ago. Because these rods are metallic and sit close to the spinal cord, both safety and image quality deserve attention. The good news is that modern research and scanning protocols have made MRI feasible for the vast majority of these patients.

Why Metal Implants and MRI Raise Concerns

An MRI scanner generates a powerful magnetic field along with bursts of radiofrequency energy. When metal is inside the body, three things can theoretically happen. The magnet could pull on the implant or twist it. The radiofrequency pulses could heat the metal. And the metal could warp the images so badly that the scan becomes useless for diagnosis. For a rod that runs along the spine, right next to nerves and the spinal cord, even small problems in any of those categories would be a serious concern. That’s why MRI with spinal hardware has historically been approached with caution.

The level of risk depends heavily on what the implant is made of. Stainless steel, the material in classic Harrington rods, is more magnetic than the titanium alloys used in modern spinal instrumentation. That doesn’t automatically mean it’s dangerous in a scanner, but it does mean the screening conversation matters more. Titanium implants are essentially nonmagnetic and produce far fewer image artifacts, which is one reason the surgical world moved away from stainless steel.

What the Safety Testing Actually Shows

Researchers have directly measured how spinal rods behave inside MRI scanners, looking at force, torque, and heating. A study testing various scoliosis implants at both 1.5 T and 3 T field strengths found that the magnetically induced torque and displacement force were negligible.¹ The maximum temperature increase recorded in that study was 1.3 degrees Celsius, with heating influenced by field strength, implant length, and the presence of cross-links connecting the rods. A rise of about one degree is well within the range the body can handle without tissue damage.

Even more reassuring data comes from testing at 7 T, a field strength far higher than what clinical scanners typically use. Researchers measured temperature changes of roughly 0.7 to 1.0 degrees Celsius around metallic spinal implants during different scanning sequences, only slightly more than the 0.4 to 0.5 degrees seen in control specimens with no metal at all. The conclusion was that MRI examinations could be performed safely on patients with these implants even at that unusually strong field.² Since most clinical MRIs are done at 1.5 T or 3 T, this provides a comfortable safety margin.

So the implant isn’t going to fly out of your back, and it isn’t going to cook surrounding tissue. Those are the two biggest fears patients have, and the evidence is strongly reassuring on both counts.

The Real Problem Is Image Quality, Not Physical Safety

If you’ve ever seen an MRI taken near metal hardware, you know the issue: big dark voids and bright streaks that can obscure the very anatomy the scan was ordered to evaluate. This is the actual everyday challenge of MRI with Harrington rods. The metal distorts the local magnetic field, creating artifacts that can wipe out visibility of nearby discs, nerve roots, and the spinal canal itself.

The size of these artifacts varies with the implant material and the scanner’s field strength. Testing of titanium and cobalt-chromium scoliosis rods showed that artifact width ranged from roughly 15 mm using certain sequences at 1.5 T to nearly 28 mm using other sequences at 3 T.¹ Pure titanium and titanium-aluminum alloys produced the smallest artifacts, while cobalt-chromium alloys produced the largest. Stainless steel, the material in Harrington rods, tends to produce artifacts on the larger end of this spectrum because of its higher magnetic susceptibility.

What this means in practice is that you can get an MRI with Harrington rods and it will be physically safe, but certain structures close to the rods may be hard to see. A scan looking at your knee or brain won’t be affected at all by rods in your spine. A scan of the lumbar or thoracic spine in the direct neighborhood of the hardware is where image quality becomes a real concern.

How Radiologists Work Around the Artifacts

The imaging world hasn’t just thrown up its hands at metal artifacts. Several specialized MRI sequences have been developed specifically to reduce the distortion caused by implants, and they’ve gotten significantly better over the past decade or so.

One approach, the metal artifact reduction sequence (MARS), was shown to effectively reduce tissue-obscuring artifacts from spinal hardware and subjectively improve image quality compared with standard sequences.³ Another technique called SEMAC (slice encoding for metal artifact correction) significantly reduced metal-related artifacts and improved visualization of structures right next to spinal implants, including pedicles, vertebral bodies, the dural sac, and neural foramina.⁴ A variation called VAT-SEMAC was also shown to reduce screw-related signal loss in spinal constructs.⁵

Not every MRI center has all of these sequences available, and the radiologist needs to know you have spinal hardware before the scan so the protocol can be adjusted. If you’re scheduling a spine MRI and you have Harrington rods, mention them early. The facility may choose to use a lower field strength (1.5 T rather than 3 T, since artifacts shrink at lower field strengths), select artifact-reducing sequences, or both. None of this requires you to do anything special beyond telling the scheduling staff about your implant.

The Pre-Scan Screening Process

Before any MRI, you fill out a screening questionnaire about metal in your body. If you report Harrington rods or any spinal hardware, the MRI team will want to know the material, when it was implanted, and ideally the manufacturer. This is standard procedure. An expert consensus panel generated recommendations for managing implant safety in MRI, emphasizing that the standard of care is to identify the implant and assess the safety of scanning the patient.⁶

Here’s where it gets a bit complicated for people with vintage Harrington rods. Many of these were implanted in the 1970s or 1980s, and patients often don’t have the original surgical records specifying the exact rod model and alloy. Modern implants typically carry “MR Conditional” labeling, meaning they’ve been tested and shown to be safe under specific scanning conditions. Older Harrington rods predate this labeling system entirely, which means they’re technically “unlabeled” from the MRI safety perspective.

When an implant is unlabeled, the supervising physician is responsible for deciding whether to proceed based on the risks associated with the implant and the benefit of the MRI.⁶ This is a clinical judgment call, not an automatic denial. In most cases, the physician weighs the known low risk of passive metallic implants against the diagnostic need for the scan and gives the go-ahead. If you’ve been told you “can’t” have an MRI because of Harrington rods, it’s worth getting a second opinion from a center experienced with implant patients, because blanket refusals often reflect overly cautious policies rather than genuine danger.

Why You Might Need a Spine MRI Decades After Surgery

People who had Harrington rod fusions as teenagers are now often in their 40s, 50s, or 60s, and new spinal problems become more common with age. One of the more frequent issues is adjacent segment disease, where the levels above or below a long spinal fusion start to degenerate faster than they would have on their own because they’re absorbing extra mechanical stress. Researchers evaluating patients at least 10 years after posterior lumbar fusion found increased disc degeneration and worsening spinal stenosis at adjacent levels, with MRI used to assess these changes over time.⁷

MRI is particularly valuable for these follow-up evaluations because it shows soft tissue detail that X-rays and CT scans cannot. Disc bulges, nerve compression, spinal cord changes, and early signs of stenosis are all best visualized with MRI. If your doctor suspects a new problem developing near your old fusion, telling you to just skip the MRI because of the rods means missing the very pathology the scan is designed to detect. The diagnostic benefit almost always outweighs the image quality limitations, especially with modern artifact-reduction techniques available.

Stainless Steel Versus Titanium and What It Means for You

If your rods were implanted after the mid-1990s, they’re almost certainly titanium or a titanium alloy. These are firmly MR Conditional and produce relatively modest artifacts. If you had surgery in the 1970s or 1980s, your Harrington rods are likely 316L stainless steel. This is where patients tend to get conflicting information, because some MRI centers treat all stainless-steel implants as a reason to decline the scan.

Stainless steel is weakly attracted to magnetic fields, but 316L surgical-grade stainless steel is among the least magnetic stainless steels in common use. After decades inside the body, scar tissue has thoroughly encapsulated the rods and screws, which provides an additional layer of mechanical stability against any movement. The evidence from laboratory testing at field strengths up to 7 T shows minimal heating and negligible force even for metal spinal implants.² The practical concern with stainless steel is almost entirely about image quality, not physical risk.

That said, if you know (or can find out) the specific model and material of your hardware, bring that information to the MRI appointment. Old surgical records, operative reports, or even the implant manufacturer’s card if you were given one can make the screening process much smoother. If records are unavailable, a plain X-ray of the spine can help the MRI safety team identify the general type and configuration of the implant.

What to Expect During the Scan

Some patients with spinal hardware report feeling warmth or a mild pulling sensation during an MRI. These sensations are generally not dangerous, but they can be unsettling if you aren’t prepared for them. The warmth comes from the radiofrequency energy interacting with the metal, and as the safety data shows, the actual temperature increase is quite small. If anything feels genuinely painful or alarming, you’ll have a call button to alert the technologist immediately, and the scan can be paused or stopped.

The scan itself takes the same amount of time as it would for someone without hardware, though the use of artifact-reduction sequences can occasionally add a few extra minutes. You lie still, hear the usual loud knocking and buzzing, and wait. Nothing about having Harrington rods changes the fundamental experience. Many patients who were anxious about the scan report afterward that it was far less eventful than they expected.

When an MRI Might Not Be the Best First Choice

Even though MRI is generally safe with Harrington rods, it isn’t always the best imaging study for every clinical question. If your doctor wants to check the integrity of the rods themselves, looking for rod fractures, hook loosening, or screw pullout, a CT scan is usually more informative because it shows bone and metal detail with high resolution and no susceptibility artifacts. Plain X-rays remain the standard first-line study for assessing overall spinal alignment, hardware position, and fusion status.

MRI earns its role when the question involves soft tissue: Is a disc herniating? Is the spinal canal narrowing? Is the spinal cord itself being compressed? For these questions, MRI remains the gold standard, and having Harrington rods shouldn’t prevent you from getting one when your clinical team determines it’s needed.

Flatback Syndrome and the Long-Term Harrington Rod Legacy

One issue that brings many Harrington rod patients back to spine specialists decades later is flatback syndrome. The original Harrington rod was a distraction device designed to straighten scoliotic curves by pulling the spine into alignment. It worked well for correcting side-to-side curves, but it often reduced or eliminated the natural forward curve (lordosis) of the lower back. Over time, as the adjacent discs degenerate and the spine settles, some patients develop a fixed forward lean that makes it difficult to stand upright without bending their knees or hips.

Evaluating flatback syndrome typically requires both standing X-rays to measure alignment and MRI to assess the condition of the discs, facet joints, and neural structures. Revision surgery for flatback syndrome is complex, and the surgical team needs detailed imaging of the soft tissue to plan the approach. Refusing to do an MRI because of the rods would leave surgeons working with incomplete information about the very spine they’re trying to fix. This is a scenario where the diagnostic benefit is obvious and the safety profile supports proceeding.

How Implant Labeling Works and Why Older Hardware Falls in a Gray Zone

Modern orthopedic and spinal implants go through MRI safety testing before they reach the market. Manufacturers test each device at specific field strengths and under specific conditions, then publish labeling that falls into one of three categories: MR Safe (no metal at all, safe under any conditions), MR Conditional (safe under defined conditions such as a maximum field strength or specific absorption rate), or MR Unsafe (should not enter the scanner). Most contemporary spinal hardware is labeled MR Conditional at 1.5 T and 3 T.

Harrington rods were designed and implanted before this labeling system existed. That absence of formal labeling can trigger institutional protocols that default to “do not scan.” But the absence of a label is not the same as the presence of danger. As one consensus review noted, implants typically carry MR Conditional labeling at 1.5 and 3 T only, and when a scanner operates at a field strength without labeling for the device, the supervising physician must make a benefit-risk decision.⁶ The same principle applies to unlabeled hardware at standard field strengths. The physician reviews what is known about the material, the configuration, and the patient’s clinical need, and makes a judgment. The research data on spinal implants across a range of alloys and field strengths supports the safety of scanning in the vast majority of cases.

If you’re in this gray zone, the practical advice is to seek out an MRI facility affiliated with a large academic medical center or a hospital with a dedicated MRI safety program. These centers deal with complex implant patients regularly and are far less likely to issue a blanket refusal than a standalone outpatient imaging center that simply doesn’t want the liability headache.