Minimally Invasive Procedure Can Treat Spinal Fractures Due to AS, Study Says

Percutaneous interbody fusion (PIF), a minimally invasive and potentially safer procedure, is feasible to stabilize spinal fractures due to ankylosing spondylitis (AS) and complicated by pseudarthrosis, a Chinese study has found.

One day after the intervention, patients felt relief from spinal pain and disability.

The study, “Feasibility of percutaneous interbody fusion as a treatment for adjacent vertebral stress fracture of ankylosing spondylitis with intervertebral pseudarthrosis formation,” was published in the Journal of Pain Research.

Ankylosing spondylitis (AS) is a form of arthritis that primarily affects the spine, although other joints can also become involved. It causes inflammation of the spinal joints (in vertebrae) that can lead to severe chronic pain and stiffness.

The hallmark sign of AS is inflammation of the sacroiliac joints, where the base of the spine (the sacrum) meets the pelvis (iliac bone).

In more advanced cases, this inflammation can lead to ankylosis — new formation of bone in the spine — causing sections of the spine to fuse in a fixed position.

This can lead to an increased risk of spinal fracture because of the limited range of movement and because the spine of an AS patient is typically weaker and marked by osteoporosis. Because of that, people with AS are more prone to experience a stress fracture which “can occur with minor trauma or even unknown trauma,” researchers said.

Management of stress fractures in these patients can be particularly challenging, because it can be accompanied by pseudarthrosis — a type of “false joint” that results from the abnormal union of a bone fracture. This requires alleviating pain caused by both the fractured vertebrae and unstable pseudarthrosis, the researchers explain in the study.

The team, composed of researchers from China’s Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, wanted to evaluate whether it was feasible to use a new form of percutaneous interbody fusion (PIF) to treat these patients.

The authors say that they have developed an innovative and minimally invasive surgery, based on percutaneous vertebroplasty — a newer technique in which a bone cement is injected though a needle into the painful, fractured vertebra.

To evaluate the success of the intervention, they retrospectively analyzed data from 11 patients — seven men and four women, ages 33–80, who underwent PIF for adjacent stress fractures of AS with intervertebral pseudarthrosis at the hospital between 2010 and 2018.

The data confirmed full “technical success” of the procedure. CT scans showed all patients had a good fusion of affected vertebrae with the bone cement. Leakage occurred in one case without causing any clinical complications.

Following the intervention, patients felt a significant alleviation of symptoms, reporting reductions in pain and disability, as measured by the Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI, specific for disability due to low back pain).

Mean VAS scores dropped from 8.82 before the procedure to 3.36 and 2.73 one day after and one month after the procedure, respectively. Mean ODI scores decreased from 82.91 before treatment to 31.64 and 30.00.

The procedure took nearly 50 minutes on average (range 42–65 minutes), and required a mean hospital stay of seven days.

“PIF is a highly feasible technique, which can significantly relieve pain and stabilize the fractured spine,” the researchers stated.

This procedure may be useful for selected patients, particularly for those in poor general condition. It has several advantages. It is minimally invasive and requires only local anesthesia, potentially decreasing the risk of infection and blood loss and avoiding damage to the adjacent tissues, especially the spinal cord.

Also, the short period of bed rest and a short hospital stay “can certainly decrease the risk of thromboembolic complications [when a blood clot plugs a vessel],” the researchers said.

“Moreover, it appears to be a promising alternative for patients who are not candidates for surgical stabilization and conservative therapy. However, further studies with a larger sample size, which compare this procedure with other available treatments, are required to confirm these preliminary findings,” they concluded.