Natural history of Chiari I malformation in children: a retrospective analysis.

PURPOSE: While there are increasing numbers of studies published regarding Chiari I malformation (CM1) in children, most of these focus on surgical indications, technique, and outcomes. Few studies examine the natural history of CM1 once the decision is made to treat a patient conservatively. In this study, we seek to determine the percentage of pediatric patients who undergo surgery for CM1, both after initial consultation and in a delayed fashion, the natural history of CM1 after a decision to pursue non-operative management, and attempt to identify patient factors that may predict development of new or worsening CM1 symptoms.

METHODS

From our database of 465 pediatric patients with CM1, we identified those who were seen for initial consultation from July 1, 2011, to June 30, 2016. We examined rates of surgical intervention, types of surgical intervention, age, gender, and presence or absence of headache and syrinx, and looked carefully at the patients who had new or worsening symptoms prompting delayed surgical intervention.

RESULTS

We identified 226 patients meeting inclusion criteria. Overall, 15% of patients had surgery, the majority being Chiari decompression. Just over half of these patients had surgery within 6 months of initial consultation. Of those with delayed surgery, only 4 patients had new symptoms/syrinx and 1 patient had symptom progression. The other patients had various reasons for surgical delay not related to symptom development or progression. There were no obvious commonalities among these 5 patients that could predict progression prospectively. All patients who had surgery did so within 2 years of initial consultation.

CONCLUSION

Overall, the natural history of asymptomatic CM1 is benign. Patients treated non-operatively are unlikely to progress. If they do progress, this is likely to occur within 2 years of initial consultation. There were no factors identified in this study that predicted new or worsening symptoms over time.