Autograft (bone taken from the patient) are still alive and capable of producing more bone cells. The up side is that there are no problems at the donor site with pain, infection, or poor wound healing. It just gives a scaffold or place for the patient’s body to fill in with bone produced during the healing phase. There are advantages and disadvantages for each choice.Īllograft (donor bone from a bank) is dead and doesn’t produce new bone. But for the patient with painful symptoms, if no graft was used in the first procedure, the surgeon may choose to take bone from a donor bank or from the patient and place it around the fusion site. If there are no symptoms, then it might warrant a wait-and-see approach. Once the diagnosis has been made, what is the treatment for pseudarthrosis? What can the surgeon do for this problem? Some of the decision depends on how the first fusion was done and the location (neck or low back). Only patients with painful, disabling symptoms would undergo a second (diagnostic) procedure. When imaging studies do not aid in the diagnosis, the surgeon can rely on a follow-up surgical procedure to confirm any diagnostic suspicions. Not enough study has been done to clear up any questions about these modalities. There has been some question about the use of ultrasound and bone scans to help diagnose pseudarthrosis. Those changes interfere in judging whether or not the fusion is completed. MRIs can be a bit iffy in patients with hardware in place because the implants cause artifacts (unexplained shadows and altered densities). Locked pseudoarthrosis describes a situation in which the top and bottom of the cage inserted between the two vertebrae has fused solid but the middle (inside the cage) has not filled in with bone and solidified. Thin-cut CT scans help show this problem more clearly than dynamic radiographs. The one exception to this is in the case of locked pseudoarthrosis. But the results don’t really add anything more than what is seen on the X-rays.
Thin-slice CT scans have been used to assess the fusion site. Some experts think there’s a difference in springiness between a fusion with and without hardware to hold it together during the healing phase. There’s a lot of debate about what is and what isn’t a solid fusion. And just how much motion constitutes a failed fusion remains fuzzy. When reading dynamic radiographs, the radiologist knows that just because there isn’t any obvious motion doesn’t mean the fusion is complete. When it comes to diagnostic imaging, there just isn’t a good way to tell if the fusion failed. But this method isn’t very reliable and wouldn’t be done routinely after surgery if the patient wasn’t having any problems. Dynamic means the X-rays are taken as the patient is moving. How does the physician diagnose pseudarthrosis? It can be discovered in the patient who doesn’t have any real symptoms when dynamic imaging studies are done. But anyone who has reduced blood supply or metabolic disorders such as heart disease or diabetes can also experience delayed wound healing or infections that can leave patients with lower fusion rates.
So, who’s at risk for pseudarthrosis? Smokers and patients who do not follow the guidelines for movement restriction during the post-operative period are at the greatest risk of failed fusion. To help us understand why this happens, the authors present the many possible risk factors, and then walk us through the diagnosis and follow-up treatment.
There can be other causes of failed spinal fusion such as the hardware coming loose or infection and poor wound healing, but pseudarthrosis accounts for almost one-fourth of all revision fusion surgeries. Or it can cause back and leg (or arm) pain, depending on whether the fusion is at the cervical (neck) or lumbar (low back) level. It can occur without symptoms so the patient doesn’t even know he or she has it. Pseudarthrosis means false joint and refers to movement that occurs at the fused site. In this review article, orthopedic spine surgeons from George Washington University Medical School bring us up-to-date on the problem of pseudarthrosis after spinal fusion. Even so, there is a major concern about the number of failed spinal fusions requiring revision (a second) surgery. And that’s because surgeons now have at their disposal better ways to perform the surgery and improved hardware such as pedicle screws and locking plates to hold the bones together. Surgical fusion of the spine for degenerative disease is becoming a popular way to treat this problem.