Pseudoathrosis (Failed Fusion)
How Do You Know if Your Bones Didn't Heal after Surgery?
Question: How can I know if I have pseudoarthrosis (failed fusion)? I had a fusion at L4-S1 21 months ago with considerable improvement after 6 months and very little change since. Is something wrong?
— Litchfield, CT
Answer: No, it sounds like you had a very successful surgery and fusion!
It usually takes six to nine months for your bones to fuse after a spinal fusion surgery. During that time, I'm sure your surgeon and nurse kept you on activity restriction: for example, no heavy lifting, bending, or twisting. Your bones are working hard to knit themselves back together after a spine surgery, so it's crucial to not strain your back too much during that time.
In the months following your surgery, you probably had follow-up appointments with your surgeon to check on your progress. During those appointments, he or she most likely had x-rays or CT scans done. X-rays and CTs are the most useful imaging tests to check on how your bones are healing and fusing. They show the bones the best.
In those x-rays and / or CT scans, your surgeon is looking for evidence of either a successful or failed fusion. One of the best signs for pseudoarthrosis (failed fusion) is a halo formation on the x-ray or CT scan. This appears around a screw used in the surgery to stabilize your spine until the bones fuse and area able to provide support and stability. If the fusion doesn't happen as it should (pseudoarthrosis), the screws can loosen. These loose screws will show up with a ring around them—a halo formation—on the x-ray or CT scan.
A halo formation is a good way to tell if your vertebrae have not fused. If your surgeon noticed this on your x-rays or CT scans, he or she should've pointed it out to you.
To me, it seems like you showed good improvement during that very vital first year after surgery. You say you showed considerable improvement after 6 months, and that indicates to me that your bones fused well. In successful surgeries, you should show improvement in pain and function (what you're able to do); it may be slow at first, but as your bones heal and your body readjusts, you should notice a marked difference, especially when compared to your life and pain level before surgery.
Then, you'll reach a plateau. After your bones fuse and your life gets back to normal, there isn't a whole lot left to improve.
So congratulations: you're 21 months post-surgery, and you're doing well. Even without seeing your x-rays or CT scans, I'd say that you do not have pseudoarthrosis but that you do have a spine surgery success story.