Related Experiment Video
Updated: Dec 10, 2025
Intrathecal Application of a Fluorescent Dye for the Identification of Cerebrospinal Fluid Leaks in Cochlear Malformation
Published on: February 29, 2020
Achondroplasia Foramen Magnum Score: screening infants for stenosis
Moira S Cheung1, Melita Irving2, Alessandra Cocca3
1Department of Paediatric Endocrinology, Evelina London Children's Hospital, London, UK Moira.Cheung@gstt.nhs.uk.
Insights
Achondroplasia in infants is linked to foramen magnum stenosis (FMS), increasing risks. A novel MRI score (AFMS) helps detect FMS severity, guiding necessary interventions to prevent infant morbidity and mortality.
Area of Science:
- Pediatric Neurology
- Radiology
- Genetics
Background:
- Achondroplasia is associated with foramen magnum stenosis (FMS), posing significant risks of morbidity and mortality in infants.
- Early detection of FMS is crucial for identifying infants who may require surgical intervention.
Purpose of the Study:
- To describe the incidence and severity of FMS in infants with achondroplasia.
- To introduce and validate a novel MRI scoring system, the Achondroplasia Foramen Magnum Score (AFMS).
- To correlate FMS severity with clinical examination findings and cardiorespiratory sleep (CRS) study data.
Main Methods:
- Development of the Achondroplasia Foramen Magnum Score (AFMS).
- Retrospective correlation of AFMS scores with clinical and CRS data over a 3-year period in a series of infants.
- Analysis of FMS severity, including cerebrospinal fluid (CSF) space, spinal cord distortion, and signal changes.
Main Results:
- Out of 36 infants, varying degrees of FMS were observed, with 13.9% showing cervical cord signal change (AFMS4).
- Mean Total Apnea and Hypopnea Index (TAHI) increased with FMS severity, particularly in AFMS3-4.
- Clinical neurological examination was normal in 94% of patients, while 25% required neurosurgery.
Conclusions:
- Clinical examination and CRS studies show low sensitivity in predicting spinal cord effects of FMS.
- Routine MRI screening using the AFMS can aid in early detection of spinal cord changes.
- The AFMS has the potential to reduce infant morbidity and mortality associated with FMS in achondroplasia.
Background:
Achondroplasia is associated with foramen magnum stenosis (FMS) and significant risk of morbidity and sudden death in infants. A sensitive and reliable method of detecting infants who require decompressive surgery is required. This study aims to describe the incidence and severity of FMS in an unselected, sequential series of infants using a novel MRI score and retrospectively correlate severity with clinical examination and cardiorespiratory sleep (CRS) studies.
Methods:
The Achondroplasia Foramen Magnum Score (AFMS) was developed and scores were retrospectively correlated with clinical and CRS data over a 3-year period.
Results:
Of 36 infants (M:F, 18:18), 2 (5.6%) did not have FMS (AFMS0); 13 (36.1%) had FMS with preservation of the cerebrospinal fluid (CSF) spaces (AFMS1); 3 (8.3%) had FMS with loss of the CSF space but no spinal cord distortion (AFMS2); 13 (36.1%) had FMS with flattening of the cervical cord without signal change (AFMS3); and 5 (13.9%) had FMS resulting in cervical cord signal change (AFMS4). Mean Total Apnea and Hypopnea Index (TAHI) for AFMS0-4 was 3.4, 6.41, 2.97, 10.5 and 25.8, respectively. Severe TAHI had a specificity of 89% but only a 59% sensitivity for AFMS3-4. Neurological examination was normal in 34/36 (94%) patients. Overall, 9/36 (25%) infants required neurosurgery with minimal surgical complications.
Conclusions:
Clinical examination and CRS have a low sensitivity for predicting the effects of foramen stenosis on the spinal cord. Routine screening with MRI using AFMS can aid in detecting early spinal cord changes and has the potential to reduce infant morbidity and mortality.
