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Abnormal subcortical somatosensory evoked potentials indicate high cervical myelopathy in achondroplasia
1Paediatric Neurology, University Children's Hospital, Johannes-Gutenberg University, Mainz, Germany. boor@kinder.klinik.uni-mainz.de
Insights
Somatosensory evoked potentials (SEPs) effectively detect cervical myelopathy in children with achondroplasia. Early detection using subcortical SEPs aids in preventing neurological damage and sudden death in these patients.
Area of Science:
- Neurology
- Pediatrics
- Medical Imaging
Background:
- Children with achondroplasia are at risk of cervical myelopathy due to cranio-cervical junction stenosis.
- This condition can lead to neurological disability and increased risk of sudden death.
- Early detection of myelopathy is crucial for timely intervention.
Purpose of the Study:
- To evaluate the utility of somatosensory evoked potentials (SEPs) in detecting cervical myelopathy in children with achondroplasia.
- To compare the sensitivity and specificity of conventional SEPs with subcortical SEPs.
- To correlate SEP findings with clinical status and MRI results.
Main Methods:
- Somatosensory evoked potentials (SEPs) were recorded in 30 children with achondroplasia (aged 13 months to 18 years) using median nerve stimulation.
- Both conventional SEPs (cortical N20, central conduction time) and subcortical SEPs (N13b, P13) with a noncephalic reference were employed.
- Findings were correlated with clinical examinations and magnetic resonance imaging (MRI) results.
Main Results:
- SEPs demonstrated high sensitivity for detecting cervical cord compression (0.89), myelomalacia (0.92), and clinically symptomatic patients (1.0), with no false positives.
- Subcortical SEPs were more sensitive than conventional recordings for detecting myelopathy.
- Conventional SEPs showed high specificity (1.0 for myelomalacia, 0.96 for symptomatic patients) in severely affected individuals.
Conclusions:
- Analysis of SEPs, particularly subcortical tracings, is valuable for early detection of cervical myelopathy in pediatric achondroplasia.
- Early neurosurgical decompression guided by SEP findings may prevent irreversible neurological damage.
- SEP monitoring can aid in managing achondroplasia-related spinal cord complications.
Unlabelled:
Children with achondroplasia may have high cervical myelopathy due to stenosis of the cranio-cervical junction resulting in neurological disability and an increased rate of sudden death. To detect myelopathy we recorded somatosensory evoked potentials (SEPs) after median nerve stimulation in 30 patients with achondroplasia aged 13 months to 18 years (mean 6 years). In addition to the conventional technique of recording the cortical N20 and the central conduction time (CCT), we employed a noncephalic reference electrode recording the subcortical waveforms N13b and P13. generated near the cranio-cervical junction. The findings were related to the clinical status and MRI results. Eighteen patients had MRI evidence of spinal cord compression with indentation or narrowing of the upper cervical cord, and 13 showed signs of myelomalacia. Seven patients had neurological abnormalities. The sensitivities of the SEPs were 0.89 for cervical cord compression, 0.92 for myelomalacia and 1.0 for the clinically symptomatic patients. There were no false-positive results. The subcortical SEPs were more sensitive than the conventional recordings. However, the conventional SEPs were highly specific in the most severely affected patients; here the specificity was 1.0 for patients with myelomalacia and 0.96 for symptomatic patients. Postoperative SEPs improved after occipital decompression in two children.
Conclusion:
The analysis of somatosensory evoked potentials, in particular of subcortical tracings, is useful in the detection of early cervical myelopathy in children with achondroplasia. Early neurosurgical decompression may prevent irreversible damage.