Increase in clivo-axial angle is associated with clinical improvement in children undergoing occipitocervical fusion for complex Chiari malformation: patient series

Abstract

BACKGROUND The authors analyzed the pre- and postoperative morphometric properties of pediatric patients with complex Chiari malformation undergoing occipitocervical fusion (OCF) to assess clinical outcomes and morphometric properties that might influence postoperative outcomes. OBSERVATIONS The authors retrospectively reviewed 35 patients younger than 22 years with Chiari malformation who underwent posterior fossa decompression and OCF with or without endoscopic endonasal odontoidectomy at their institution (13 with and 22 without odontoidectomy). Clivo-axial angle (CXA), pB-C2, atlantodental interval, basion-dens interval, basion-axial interval, and canal diameter at the level of C1 were measured on preoperative and approximately 3-month postoperative computed tomography or magnetic resonance imaging. The authors further stratified the patient cohort into three age groups and compared the three cohorts. The most common presenting symptoms were headache, neck/shoulder pain, and dysphagia; 80% of the cohort had improved clinical outcomes. CXA increased significantly after surgery. When stratified into those who showed postoperative improvement and those who did not, only the former showed a significant increase in CXA. After age stratification, the significant changes in CXA were observed in the 7- to 13-year-old and 14- to 21-year-old cohorts. LESSONS CXA may be the most important morphometric predictor of clinical outcomes after OCF in pediatric patients with complex Chiari malformation.

Intraoperative occipital to C2 angle and external acoustic meatus-to-axis angular measurements for optimizing alignment during posterior fossa decompression and occipitocervical fusion for complex Chiari malformation

“…We previously showed the association of short-term CT/MRI skull base morphometric changes after OCF with positive clinical outcomes in both adults and children. [ 9 , 18 ] This particular study extended those findings by examining the utility of X-ray morphometrics on preventing postoperative complications in complex CM patients undergoing PFD and OCF. Based on these observations, we described via case examples a novel method to use such predictive markers pre- and intraoperatively.…”

“…Furthermore, CT and MRI are used to evaluate skull base morphometrics, such as the clivo-axial angle (CXA), that we have previously described. [ 9 , 18 ] Ventral compression due to restricted CSF space between the clivus and the upper cervical spine often results in an acute CXA and bulbar symptomology. [ 3 , 17 ] Our prior work, along with previous studies, demonstrated significant corrections to CXA in successful OCF cases.…”

“…[ 7 ] In previous studies, it has been demonstrated that short-term positive postoperative computed tomography (CT)/magnetic resonance imaging (MRI) skull base morphometric changes after OCF with or without ventral decompression were associated with improved clinical outcomes in both adults and children, suggesting the importance of increased attention to intraoperative morphometrics. [ 8 , 9 ]…”

Reoperation in Chiari-1 Malformations

“…This series included a patient with misrecognized basilar impression, which was the cause of the failure. Odontoidectomy has been recommended in the case of CM-1 with ventral compression [5,56]. It has been recommended to try reducing the basilar impression before removing the dens [57].…”

Craniocervical instability in patients with Ehlers-Danlos syndromes: outcomes analysis following occipito-cervical fusion

“…A growing body of literature suggests that chronic CCI manifests as a broad array of deleterious biomechanical effects upon the neural axis, in addition to causing altered cerebrospinal fluid and vascular flow [ 4 , 8 , 9 , 12 , 15 – 17 , 20 ]. Headaches, long tract findings, motor delay and quadriparesis, dyspraxia, gait instability, and altered autonomic function are recognized as consequences of chronic biomechanical deformation of structures at the craniocervical junction in many hereditary connective tissue disorders [ 8 , 13 , 16 , 19 , 21 – 25 ].…”