Atlantoaxial instability (AAI) is a common but potentially severe complication in pediatric patients with Down syndrome, while its surgical characteristics and outcomes remain understudied compared with non-Down syndrome populations. To compare the clinical presentation, radiological features, surgical strategies, and postoperative outcomes of AAI between pediatric patients with Down syndrome and matched non-Down syndrome controls. A retrospective case-match study was conducted, including 15 patients with Down syndrome along with AAI who underwent surgical atlantoaxial arthrodesis between 2009 and 2022. Each case was matched with two non-Down syndrome controls by age, sex, and AAI severity. The patients were divided into two groups: the Down syndrome group (group DS) and the control group (group C). Data included clinical presentation, radiographic parameters atlantodental interval (ADI) and space available for the spinal cord (SAC), surgical approach, complications, and fusion rates were compared between the two groups. Patients with Down syndrome exhibited a higher incidence of neurological symptoms (12/15, 80%) compared with controls (5/30, 16.7%) (P < 0.05). Os odontoideum was more common in patients with Down syndrome (10/15, 66.7%), while rotatory dislocation was more common in patients with non-Down syndrome (9/30, 30%); nine (60%) in group DS and one (2.9%) in group C had a high-signal area on MRI. Preoperative ADI was larger for group DS compared with group C (9.0 vs. 7.4 mm; P < 0.01). The ADI and SAC were significantly corrected and were comparable at the last follow-up. Preoperative Japanese Orthopaedic Association scores were significantly smaller in group DS compared with group C (13.3 vs. 16.5; P < 0.01). Neurological symptoms were significantly improved in all patients at the last follow-up. All included patients underwent posterior atlantoaxial screw-rod fixation and fusion. Only two patients suffered superficial wound infection at the iliac bone area, and another patient in the neck (20%), and no complications occurred in group C. Solid fusion was shown in all patients by the time of the last follow-up. Pediatric patients with AAI often have os odontoideum and hypoplasia of the dental process. Posterior atlantoaxial screw-rod fixation can result in good fusion and neurological function recovery.
Liu et al. (Tue,) studied this question.