Posterior Correction and Fixation Without Anterior Fusion for Pseudoarthrosis With Kyphotic Deformity in Ankylosing Spondylitis

Abstract

Posterior correction and fixation is effective for treating pseudarthrosis with kyphosis in ankylosing spondylitis. No anterior fusion procedure was necessary.

Pedicle subtraction osteotomy through pseudarthrosis to correct thoracolumbar kyphotic deformity in advanced ankylosing spondylitis

“…As the thoracolumbar region in advanced AS patients with kyphotic spine acts as a fulcrum between the ossified thoracic and lumbar spine, a stress fracture tends to occur at such a site of high stress forces [4] and more commonly through the intervertebral disc space, as the ankylosed disc presents less resistance than the vertebral body [11]. In addition, persistent motion at the fracture site between the long lever arms makes spontaneous union difficult [4], resulting in the formation of pseudarthrosis.…”

“…The three-column involved pseudarthrotic lesion is extremely unstable, and may result in progressive thoracolumbar kyphotic deformity, sagittal imbalance, intractable pain, and neurological deficit [4,14,16,23]. Its surgical indication has been well documented in literature [2,4,16,23].…”

“…Therefore, AS patients in advanced stage are more susceptible to fracture due to the rigidity of the ossified spine and osteoporosis [18,19,22]. A stress fracture is most likely to occur in thoracolumbar junction, a region with tremendous stress forces concentrated [4]. Persistent and abnormal motion at the stress fracture site makes spontaneous healing difficult, which leads to the formation of pseudarthrosis [20].…”

“…Additionally, it may associate with severe back pain, progressive myelopathy, and neurologic sequelae [1,4,14].…”

“…However, there is controversy regarding the optimal surgical procedure. Some authors believe that anterior fusion allows direct access to the anterior lesion [11,16], whereas others consider that pseudarthrosis can be treated effectively by posterior, transpedicular wedge resection osteotomy at the level of pseudarthrosis and fixation without supplemental anterior fusion [4,23]. Most surgeons recommend combined anterior and posterior approach for the treatment of pseudarthrosis and kyphotic deformity [6,16].…”