019. Intraoperative MRI during pediatric Chiari-I surgery aids in the decision to perform duraplasty or further decompression without increased infection or complications: a multicenter experience

Authors: Ryan James Jafrani, MD

A significant proportion of pediatric patients undergoing Chiari 1 surgery will require subsequent reoperation for continued symptoms. Determining which patients will fail to improve after Chiari 1 decompression surgery remains an area of active interest. Intraoperative imaging provides immediate information regarding the degree of decompression as well as CSF flow dynamics at the foramen magnum, which can aid in determining the need to perform an expansile duraplasty or further decompression at time of initial surgery.Methods: The IMRIS Multicenter iMRI Neurosurgery Database (I-MIND) was used to retrospectively identify pediatric patients who underwent intraoperative MRI (iMRI) during decompression of Chiari malformations. Intraoperative MRI data, OR times, complications, and follow-up were recorded.
185 patients underwent extradural decompression with the use of iMRI from 4 neurosurgeons at two institutions from 2007-2021. 70 (48.6%) were female. Median age was 8 years (range 1-18 years). Duraplasty was performed after iMRI in 58 (31.4%) patients. A second iMRI was performed in 29 (15.7%) patients with of 4 (2.2%) of these undergoing additional decompression. Average operative time was 2.6±0.9 hours and total OR time was 5.1±1.1 hours. Post-operative complication rates were comparable to those published in the literature, with 1 wound infection, 2 patients with meningitis, 5 with pseudomeningocele, 5 CSF leaks requiring temporary CSF diversion, and 2 with hydrocephalus. Average operative and total OR times for the 3 patients with infectious complications did not significantly differ from the overall cohort at 2.1 and 5.1 hours, respectively. There were no MRI related complications.
Intraoperative MRI is safe and provided valuable information leading to expansile duraplasty or other additional decompression at initial surgery in 58 of 185 pediatric patients (31.4%) who underwent Chiari surgery.