Acute flaccid myelitis (AFM) is an anterior horn disorder that manifests as rapid onset muscle weakness or paralysis. Development of scoliosis in pediatric AFM patients has been anecdotally reported, but associated risk factors or incidence have yet to be determined.
Pediatric AFM patients treated over a 10-year period at a tertiary care center were identified. Patients were considered to have scoliosis if there was radiographic evidence of coronal curvature ≥15 degrees. Number of limbs affected, independent ambulation and head control, ventilator requirement at initial admission, and long-term ventilatory support (≥1 year) were recorded. Muscle strength and functional status were assessed by manual muscle testing (MMT) and Physical Abilities and Mobility Scale (PAMS), respectively. Areas of spinal cord lesion on initial MRI were recorded. Bivariate analyses were performed, with alpha set to 0.05.
Fifty-six AFM patients (27 scoliosis, 29 no scoliosis) were identified. Mean time from AFM presentation to scoliosis diagnosis was 0.93 years. Mean major Cobb angle at first radiograph was 31.7 ± 14.3 degrees. Lack of independent ambulation, ventilator dependence at time of admission or long term, number of limbs affected, and decreased MMT and PAMS scores were more common in patients who developed scoliosis (all, p < .05). Patients who developed scoliosis had more extensive thoracic spinal cord involvement on initial MRI (p = .03).
AFM patients who develop scoliosis are more likely to be ventilator dependent, lack independent ambulation, and have more extensive thoracic SCI.