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Updated: May 29, 2026
Midface Hypoplasia and Cranial Base Morphology in Syndromic Craniosynostosis: A Comparative Analysis Study Using a Predictive Regression Model
Published on: November 4, 2025
Chiari malformation associated with craniosynostosis
Jennifer Strahle1, Karin M Muraszko, Steven R Buchman
1Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan 48709-5338, USA.
Insights
Chiari malformation (CM) is common in craniosynostosis patients, particularly with lambdoid or pansynostosis. Surgical repair of craniosynostosis can sometimes resolve CM and spinal cord syrinx, but de novo CM development can occur.
Area of Science:
- Neurosurgery
- Pediatric Neurosurgery
- Craniofacial Surgery
Background:
- Chiari malformation (CM) Type I frequently co-occurs with craniosynostosis.
- Optimal management strategies for CM in pediatric craniosynostosis patients remain unclear.
Purpose of the Study:
- To report on a series of pediatric patients diagnosed with both craniosynostosis and CM.
- To discuss the management and outcomes of these complex cases.
Main Methods:
- Retrospective review of 383 patients treated for craniosynostosis over 15 years.
- Identification of patients with concurrent CM, recording demographic and surgical data.
- Analysis of MRI findings, including cerebellar tonsillar descent, hydrocephalus, and spinal syrinxes.
Main Results:
- 29 patients with both conditions were identified; 52% had hydrocephalus, and 45% were syndromic.
- CM was more prevalent in lambdoid (55%), multisuture (35%), and pansynostosis (80%) compared to coronal (6%) or sagittal (3%) synostosis.
- Craniosynostosis repair alone improved CM in 5/7 patients, and spinal syrinx resolved in both cases. De novo CM developed in 5 patients post-repair.
Conclusions:
- Chiari malformation is frequently associated with multi- and single-suture lambdoid craniosynostosis.
- Craniofacial repair can lead to resolution of CM and spinal cord syrinx in some cases.
- De novo development of CM following craniosynostosis repair is a notable occurrence.
Object:
Chiari malformation (CM) Type I is frequently associated with craniosynostosis. Optimal management of CM in patients with craniosynostosis is not well-established. The goal of this study was to report on a series of pediatric patients with both craniosynostosis and CM and discuss their management.
Methods:
The authors searched the medical records of 383 consecutive patients treated for craniosynostosis at a single institution over a 15-year period to identify those with CM. They recorded demographic data as well as surgical treatment and outcomes for these patients. When MR imaging was performed, cerebellar tonsillar descent was recorded and any other associated findings, such as hydrocephalus or spinal syringes, were noted.
Results:
A total of 29 patients with both CM and craniosynostosis were identified. Of these cases, 28% had associated occipital venous abnormalities, 45% were syndromic, and 52% also had hydrocephalus. Chiari malformation was more likely to be present in those patients with isolated lambdoid synostosis (55%), multisuture synostosis (35%), and pansynostosis (80%), compared with patients with coronal synostosis (6%) or sagittal synostosis (3%). All patients underwent surgical repair of craniosynostosis: 16 had craniosynostosis repair as well as CM decompression, and 13 patients did not undergo CM decompression. Of the 7 patients in whom craniosynostosis repair alone was performed, 5 had decreased tonsillar ectopia postoperatively and 5 had improved CSF flow studies postoperatively. Both patients with a spinal syrinx had imaging-documented syrinx regression after craniosynostosis repair. In 12 patients in whom CM was diagnosed after primary craniosynostosis repair, 5 had multiple cranial vault expansions and evidence of elevated intracranial pressure. In 5 cases, de novo CM development was documented following craniosynostosis repair at a mean of 3.5 years after surgery.
Conclusions:
Chiari malformation is frequently seen in patients with both multi- and single-suture lambdoid craniosynostosis. Chiari malformation, and even a spinal cord syrinx, will occasionally resolve following craniofacial repair. De novo development of CM after craniosynostosis repair is not unusual.
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