Preoperative radiological scoring system in Chiari malformation type 1: a surgical guide

Chiari I malformation (CM1) is often incidentally detected on neuroimaging, with a minority of cases requiring intervention. There remain variability in the available guidelines for predicting surgery in pediatric CM1 patients. The study sought to design a preoperative scoring system using key radiological factors to anticipate likelihood of surgery in pediatric CM1 patients.

A retrospective single-center study examining 122 CM1 patients identified between January 2007 to February 2020 was carried out. Radiological parameters associated with surgery as an outcome vs no surgery were collected and analyzed to develop a preoperative scoring system.

The statistically significant radiological parameters associated with surgical intervention include herniated tonsil ≥ 1 cm (85.2%), obex below McRae's line (70.4%), dilated central canal and syrinx (63.0%) and medullary kinking (51.9%). These variables were scrutinized for predictiveness in developing a 10-point preoperative scoring system.

This study highlights the association of herniated tonsil, syrinx and medullary kinking with surgery as outcome. The proposed scoring system combining these imaging features shows increasing surgery probability with higher scores, reaching 100% at score of 10 and 50% at score of 4. This system may aid in triage, screening and prioritizing the patients for urgent neurosurgical referral or for conservative management.