Nonunions in Modern Instrumented Pediatric Cervical Spine Fusions

Introduction: Modern instrumented fusion for management of pediatric cervical spine conditions has significant potential for morbidity due to uncommon diagnoses, small anatomy, decreased bony surface area, weak bone, and impact on future growth potential. Pediatric cervical spine fusions are often subject to pseudoarthrosis, reported as high as 38%. The authors evaluated a single institution’s clinical experience with modern instrumented cervical spine fusions in the pediatric population to identify risk factors and management techniques for pseudoarthrosis.

Methods: Charts for 178 pediatric patients who received a modern instrumented cervical spinal fusion were reviewed for demographic and diagnosis characteristics, surgical details, and follow up.

Results: Mean age at surgery was 12.2 ± 5.0 years (range 7 months – 21 years). 55% of patients were male. Diagnoses included 52 congenital deformities, 42 instabilities, 28 traumatic injuries, 28 tumors, and 28 os odontoideum. Average length of follow up was 5.0 ± 3.7 years. 12 patients (6.5%) experienced nonunion, defined radiographically by a lack of osseus bridging (n = 6), screw lucency (n = 5), or both (n = 1). 8 of 12 nonunion were syndromic (p = 0.03) with 31% of Down Syndrome patients experiencing nonunion (p < 0.005). Median time between index surgery and pseudoarthrosis diagnosis was 11 months (range 3 months – 3.07 years). Twelve secondary procedures to address pseudoarthrosis were performed, 11 patients requiring instrumentation revision, 7 patient receiving autograft, and 7 patients receiving recombinant-BMP. Postoperative halo was used in 50% of revisions. One patient who received a secondary procedure for pseudoarthrosis required a subsequent revision procedure.

Conclusion : Cervical spinal fusions at our institution had a 6.7% rate of pseudoarthrosis. Syndromic patients have a higher risk of nonunion and require counseling in this regard and closer follow up. In most cases of nonunion, a single revision surgery is sufficient treatment.