Background: There have been few detailed reports concerning
pseudarthrosis following spinal instrumentation and arthrodesis in adults with
spinal deformity since the introduction of modern segmental fixation
techniques. The purposes of this study were to analyze the prevalence, risk
factors, and outcome scores on the Scoliosis Research Society Instrument-24
associated with pseudarthrosis following instrumentation and arthrodesis for
the treatment of spinal deformity in adults.
Methods: A clinical and radiographic assessment of 232 adults with
spinal deformity who were treated surgically at a single institution was
conducted. The average age of the patients was 40.8 years, and the operation
was a primary procedure in 150 patients and a revision procedure in eighty-two
patients. All patients who underwent a long (four vertebrae or more) spinal
instrumentation and arthrodesis with a minimum follow-up of two years were
included in the analysis. Clinical outcomes were assessed with the Scoliosis
Research Society questionnaire.
Results: Forty patients had a pseudarthrosis. Factors that were
found to be significantly associated with pseudarthrosis were preoperative
thoracolumbar kyphosis of >20° (p < 0.0001), an age of more than
fifty-five years (p = 0.001), arthrodesis to S1 compared with arthrodesis to
L5 or a cephalad level (p = 0.002), and arthrodesis of more than twelve
vertebrae (p = 0.037). Patients with a pseudarthrosis had lower total outcome
scores on the Scoliosis Research Society questionnaire, on the average, than
those without a pseudarthrosis (p = 0.001).
Conclusions: The prevalence of pseudarthrosis following long
arthrodesis with use of modern segmental spinal instrumentation for the
treatment of spinal deformity in adults was 17%, and the clinical outcome in
these patients can be negatively affected by the pseudarthrosis.
Level of Evidence: Prognostic Level II. See Instructions
to Authors for a complete description of levels of evidence.