A Closer Look at Presenting Symptoms in Pediatric Chiari 1 Malformation with Syringomyelia and their Relationship to Long Term Outcomes

Introduction: Chiari malformation type 1 (CM1) is characterized by herniation of cerebellar tonsils below the foramen magnum, leading to brainstem compression or obstruction of cerebrospinal fluid flow. Syrinx cavities – a fluid-filled cyst within the spinal cord – are most associated with Chiari anomalies. We investigated the presenting factors of CM1 alone versus CM1 with syrinx and assessed their prognostic significance in the CM1 with syrinx cohort.

Methods: We reviewed pediatric patients (0-18 years old) with surgically managed CM1 at our institution between 2010-2023 for demographic, clinical, radiographic, surgical, and follow-up data. The Chicago Chiari Outcome Scale (CCOS) was used to quantify outcomes.

Results: 232 patients with CM1 (120/232 Male, 52%), were included with 90/232 (39%) having CM1 alone versus 142/232 (61%) CM1 with syrinx. CM1 alone had a higher rate of male sex (58% vs. 48%, p= 0. 14). Patients with syrinx were less likely to be symptomatic (80% vs. 97%, p< 0.001) and less likely to report a headache as one of their symptoms (58% vs. 78%, p=0.002). There was no statistical difference in the rates of joint issues, gait difficulties, cranial neuropathies, and myelopathic symptoms. Patients with syrinx were more likely to be diagnosed incidentally while worked up for alternative pathologies (53% vs. 21%). Consistent with this finding, 26/28 (93%) of asymptomatic CM1 with syrinx were incidental compared to 49/114 (43%) of symptomatic CM1 with syrinx (p < 0.001). Asymptomatic CM1 with syrinx was prognostically favorable relative to symptomatic, having less postoperative complications (7.1% vs. 27%, p=0.027) and on follow-up having better Chicago Non-Pain (mean 3.86 vs. 3.53, p=0.022), Complication (mean 3.89 vs. 3.69, p=0.025, and Total Scores (mean 15.18 vs. 14.40, p=0.010).

Conclusion : Patients with CM1 and syrinx present more often incidental and asymptomatic relative to CM1 alone. Asymptomatic CM1 with syrinx have fewer postoperative complications and better treatment outcomes relative to symptomatic.