OBJECT The natural and surgical history of Chiari malformation Type I (CM-I) in pediatric patients is currently not well described. In this study the authors discuss the clinical and radiological presentation and outcomes in a large cohort of pediatric CM-I patients treated with either conservative or surgical management. METHODS The authors retrospectively reviewed 95 cases involving pediatric patients with CM-I who presented between 2004 and 2013. The patients ranged in age from 9 months to 18 years (mean 8 years) at presentation. The cohort was evenly split between the sexes. Twenty-five patients underwent posterior fossa decompression (PFD) with either dural splitting or duraplasty. Seventy patients were managed without surgery. Patients were followed radiologically (mean 44.8 months, range 1.2-196.6 months) and clinically (mean 66.3 months, range 1.2-106.5 months). RESULTS Seventy patients were treated conservatively and followed with serial outpatient neurological and radiological examinations, whereas 25 patients were treated with PFD. Of these 25 surgical patients, 11 were treated with duraplasty (complete dural opening) and 14 were treated with a dura-splitting technique (incomplete dural opening). Surgical intervention was associated with better clinical resolution of symptoms and radiological resolution of tonsillar ectopia and syringomyelia (p = 0.0392). Over the course of follow-up, 20 (41.7%) of 48 nonsurgical patients who were symptomatic at presentation experienced improvement in symptoms and 18 (75%) of 24 symptomatic surgical patients showed clinical improvement (p = 0.0117). There was no statistically significant difference in resolution of symptoms between duraplasty and dura-splitting techniques (p = 0.3572) or between patients who underwent tonsillectomy and tonsillopexy (p = 0.1667). Neither of the 2 patients in the conservative group with syrinx at presentation showed radiological evidence of resolution of the syrinx, whereas 14 (87.5%) of 16 patients treated with surgery showed improvement or complete resolution of syringomyelia (p = 0.0392). In the nonsurgical cohort, 3 patients (4.3%) developed new or increased syrinx. CONCLUSIONS The overwhelming majority of CM-I patients (92.9%) managed conservatively do not experience clinical or radiological progression, and a sizeable minority (41.7%) of those who present with symptoms improve. However, appropriately selected symptomatic patients (sleep apnea and dysphagia) and those presenting with syringomyelia should be considered surgical candidates because of the high rates of clinical (75%) and radiological improvement (87.5%).
Keywords: CM-I = Chiari malformation Type I; Chiari malformation; PFD = posterior fossa decompression; PFDD = PFD with duraplasty; natural history; pediatric neurosurgery; syringomyelia.