Spondylolysis of C-2 in children 3 years of age or younger: clinical presentation, radiographic findings, management, and outcomes with a minimum 12-month follow-up.

Object. Cervical spondylolysis is a rare condition that results from a pars interarticularis defect. The C-6 level is the most frequently involved site in the cervical spine. Its clinical presentations range from incidental radiographic findings to neck pain and, rarely, neurological deficits. Although 150 patients with subaxial cervical spondylolysis have been reported, a mere 24 adult and pediatric patients with C-2 spondylolysis have been described. The long-term outcomes of very young children with bilateral C-2 spondylolysis are of great interest, yet only a few longitudinal studies exist. Methods. The authors retrospectively reviewed 5 cases of bilateral C-2 spondylolysis at Texas Children's Hospital and Riley Children's Hospital; these were combined with 5 other cases in the literature, yielding a total of 10 patients. Data regarding the patients' age, sex, C2-3 angulation and displacement, associated spine anomalies, neurological deficits, treatment, and most recent follow-up were recorded. Results. The patients' ages ranged from 3 to 36 months (mean 12.9 months). There were 6 boys and 4 girls. The C2-3 angulation, displacement, and width of pars defect were measured when available. The mean C2-3 angulation was 9.5 degrees (range 1-34 degrees), the mean C2-3 displacement was 4.78 mm (range 1.1-10.8 mm), and the mean width of the pars defect was 4.16 mm (range 0.9-7 mm). One patient developed myelopathy and spinal cord injury. All 10 of the patients were treated initially with conservative therapy: 3 with close observation alone, 1 with a rigid cervical collar, 4 with a Minerva jacket, 1 with a sternal-occipital-mandibular immobilizer, and 1 with a halo vest. Three patients ultimately underwent surgery for internal fixation due to progressive instability or development of neurological symptoms. All patients were neurologically intact at the last follow-up (mean 44.3 months, range 14-120 months). Conclusions. Based on the literature and the authors' own experience, they conclude that most very young children with C-2 spondylolysis remain neurologically intact and maintain stability in long-term follow-up despite the bony defect. This defect is often an asymptomatic incidental finding and may be managed conservatively. More aggressive therapy including surgery is indicated for those patients with a neurological deficit from spinal cord compromise secondary to stenosis and local C-2 kyphosis, progressive deformity, or worsening C2-3 instability.