Reshchikov D.A., Palm V.V., Vasiliev I.G., Rasskazchikova I.V. Cervico-medullary compression in children with achondroplasia: diagnosis and treatment. Head and neck. Russian Journal. 2021;9(1):45–53 (In Russian).
The most severe conditions in children with achondroplasia are associated with cervicomedullary compression caused by foramen magnum stenosis and hydrocephalus. The probability of a sudden death syndrome in sleep in the first year of life is up to 7.5%. The timely and complete diagnosis of such conditions and, if necessary, surgical treatment are of great importance. Aim of the study: to choose complex diagnostic procedures, determine the indications for surgical treatment and evaluate the results of the treatment. Material and methods. Since 2015, 51 children with achondroplasia have been examined. The diagnosis was confirmed by molecular genetic testing for all the children. We used MRI with SagFlow Vizualization, polysomnography, neuroophthalmological examination, and assessment of neurological status. Results. Foramen magnum stenosis with cervicomedullary compression was detected in 31 patients. In some cases, we detected a myelopathy zone with extensions to caudal zone of brain stem. Papilledema was observed in only 1 patient. Muscular hypotension was present in all patients. In 26 cases, there was a tetraparesis from 3.5 to 4 points. Hydrocephalus was detected in 29 cases. We conducted 14 polysomnographic studies. Nineteen 19 underwent surgery. Foramen magnum decompression with C1-laminectomy without duraplasty was used. The follow-up duration was from 6 to 24 month. The apnea frequency reduced both clinically and according to the polysomnography results. The hydrocephalus degree decreased, with recovering CSF flow at the foramen magnum level, and the paresis degree decreased. Until now, vp-shunt has not been used in practice.
Discussion. Children with achondroplasia suffer from narrowing of the natural openings of the skull base. The foramen magnum stenosis leads to the ischemic disorders in the cervicomedullary region, while the spread of a lesion to the caudal parts of the brainstem damages respiratory center. Ultimately, central sleep apnea develops, which is the reason for the development of sudden death syndrome in sleep. The degree of compression is determined according to the Y. Yamada methodology — low, high compression and no compression.
The genesis of hydrocephalus is mainly associated with a violation of the venous outflow through the jugular veins in the area of narrowed foramen jugularis. But, in addition to this, violation of the passage of cerebrospinal fluid through a narrow foramen magnum is important. Recovery of cerebrospinal fluid movement reduces the severity of hydrocephalus and allows to avoid the installation of a shunt system. Conclusions. The proposed diagnostic tactics allows us to fully determine the presence of life-threatening conditions in children with achondroplasia.
Timely neurosurgical treatment completely eliminates the possibility of developing sudden death syndrome in sleep and reduces the manifestations of intracranial hypertension.
Key words: achondroplasia, foramen magnum stenosis, cervicomedullary compression, central sleep apnea, decompression of the cranio-vertebral junction, cervical myelopathy