Exploring the indications, failures, and treatment of complications after a C2 to pelvis fusion

Purpose: To better elucidate the C2-related complications and treatments among ASD patients with C2–ilium fusions. Methods: A single-center series of patients who underwent a posterior spinal instrumented fusion (PSIF) from C2–ilium were included. Patient demographics, medical history, diagnosis, operative procedures, and complications were analyzed. Results: 37 C2–ilium patients were included with a mean follow-up of 2.8 years, age of 56 ± 19 years, 57% were female, and 38% had osteoporosis/osteopenia. Most patients had a prior fusion surgery 81% (N = 30), which commonly included upper thoracic to sacrum (N = 15) and cervical-thoracic (N = 5) fusions. The most common surgical indications included PJK/F (N = 12), chin-on-chest deformity (N = 5), and pseudarthrosis (N = 5). The surgical complication rate was 46% (17/37), the revision surgery rate was 38% (14/37), and 3 patients required multiple revision surgeries. Reoperations commonly addressed C2-related fractures (N = 6), wound complications (N = 5), and pseudarthrosis unrelated to C2 (N = 4). For those with C2 issues, surgery included either extension of fusion to Occiput (N = 2) and C1 (N = 4) or revision C2 (N = 2). Four patients with radiographic C2 issues were treated non-operatively in a hard collar after appearing stable on repeat imaging. Conclusion: This is the largest series of C2–ilium reconstructions with a mean follow-up of 2 years. The most common surgical indication was PJK/F, followed by chin-on-chest deformity and pseudarthrosis. The surgical complication and revision rate was 46% and 38%, respectively. The most common reason for revision surgery was C2-related fractures and screw loosening, with 43% being extended to C1 or the occiput. Long constructs from C2–ilium carry a high complication rate and require frequent follow-up to assess for long-term issues.