Bilateral pars fractures complicating long fusion to L5 in a patient with rheumatoid arthritis

Study Design.: Case report. Objective.: To report bilateral pars fractures at L5 complicating a long fusion for adult idiopathic scoliosis in a patient with rheumatoid arthritis. Summary of Background Data.: To our knowledge, there are no reports in the literature regarding bilateral pars fractures at the end instrumented vertebrae of a long fusion at the lumbosacral junction, nor reports that have evaluated long spinal deformity corrections in patients with rheumatoid arthritis. The question of ending a long fusion at L5 or S1 is controversial, and a review is presented. Methods.: We present the patient's history, physical examination, and radiographic findings; describe the surgical treatment and long-term follow-up; and provide a literature review. Results.: Bilateral pars fractures at the end instrumented vertebrae of a long construct (T4-L5) that we discovered were subsequently revised by extension of the fusion to the sacrum. Anterior structural support at L5-S1 was also provided. At the latest follow-up (46 months), the patient has had no recurrence of her symptoms. Her radiographs showed a stable construct without loss of alignment in the sagittal or coronal planes. Her rheumatoid arthritis continues to be treated with biologic, disease-modifying antirheumatic drugs. Conclusion.: To our knowledge, this is the first report of the treatment and long-term outcome of a patient with rheumatoid arthritis and bilateral pars fractures at the end instrumented vertebrae (L5) of a long deformity correction construct.