A device exists to seal the disc after a microdiscectomy and reduce the risk of a recurrence. The evidence is real, but it applies to a narrower group of patients than you might assume.
Several patients due to undergo a lumbar microdiscectomy have asked me about Barricaid, a device inserted into the disc space after surgery to help prevent a recurrent slipped disc. It is a reasonable question, and the answer depends very much on the size of one particular measurement on your scan.
The anatomy
Your spine is a stack of bones called vertebrae, with a disc cushioning each pair.
Slice across a disc and look up at it from underneath and you see two components. The nucleus sits centrally, often described as having a crab meat-like consistency, squishy and soft, acting as the shock absorber. Holding it in place is the annulus, the outer lining, which you can think of as several layers of a fabric-like material.
What happens in a disc herniation
When discs herniate and cause sciatica, the layers of that outer fabric gradually tear until they split, allowing some of the inner nucleus material to leak out and pinch the nerve.
One treatment is a microdiscectomy. We come in through the back of the spine, through a very small incision and under the microscope, and shave away the fragment of nucleus pressing on the nerve.
The difficulty is that this leaves an opening in the annulus, carrying a small risk of further material slipping out later and causing recurrent sciatica.
Though the body does repair itself
Worth knowing: the annulus is made of collagen. And collagen is precisely what our bodies lay down as scar tissue during healing. There are different types, but the essential point stands — the annulus does repair itself.
What Barricaid is
The device is a metallic component with a fabric-like material wrapped around it, plus an anchor.
Once the disc fragment has been removed, the metal anchor is fixed into the bone below the disc, and the fabric seals off the opening at the back of the disc.
The trial results
The study was conducted in patients with large openings in the annulus on MRI, generally greater than 6 mm. Over 500 patients were divided into two groups: one received the device, the other did not.
The recurrent herniation rate was around 31% in the group without the device, compared with around 18% in those who received it.
That is a meaningful difference. But the eligibility criteria matter enormously.
Who the trial actually studied
Patients were included only if the tear was around 4 to 6 mm tall, with discs at least 5 mm high, and the width of the defect between 6 and 10 mm.
That is a large tear in the lining, and relatively unusual.
For perspective, the width of the spinal canal where the disc contacts its lining and the nerves is typically only about 22 mm. So an opening approaching 1 cm represents a significant proportion of that, and it is not what we see in the majority of herniated discs we operate on.
Consider also the baseline. Studies show that across microdiscectomies generally, regardless of herniation size, the average reherniation rate is around 5% within the first twelve months.
So this trial deliberately selected a subgroup at unusually high risk because of an abnormally wide opening in the disc lining. The 31% figure is not the risk facing a typical patient.
The adverse events
A separate study looked specifically at complications from the device. The majority involved either the device migrating from where it was originally placed, or a reherniation occurring anyway.
Around 66% of patients who experienced an adverse event required further surgery.
One more thing worth understanding
When we operate on a herniated disc, we do not aim to remove all the disc material aggressively. Studies have shown that doing so leads to more post-operative pain and reduced quality of life.
What we do instead is shave away the component pinching the nerve and look for any loose fragments that might poke out again.
The key takeaway
The Barricaid device applies to a small minority of people undergoing a lumbar microdiscectomy: those with genuinely large annular defects.
If you are considering it, what matters is a careful review of you and your symptoms, how those fit with the investigations, and specifically a careful measurement of the width of the tear on your MRI. That measurement is what determines whether the trial evidence applies to you at all.
