[Dynamics of caudal dystopia of cerebellar tonsils in patients with craniosynostosis following posterior cranial distraction].

The main cause of caudal dystopia of cerebellar tonsils (CDCT) in craniosynostosis (CS) is underdevelopment of posterior cranial fossa (PCF) with its insufficient volume. Therefore, posterior cranial distraction seems to be perspective for effective enlargement of intracranial volume.

Objective: To evaluate CDCT dynamics in patients with CS after posterior cranial distraction.

Material and methods: There were 136 patients with CS who underwent posterior cranial distraction between 2011 and 2022. Of these, 32 ones were included in this study. These patients were diagnosed with CDCT after MRI. Clinical, radiological and craniometric data were analyzed.

Results: PCF volume increased by 34.8% after posterior cranial distraction. CDCT completely regressed in 56.3% of patients. Older age of patients, baseline level of CDCT and posterior angle of skull base contributed to complete regression of CDCT.

Conclusion: Posterior cranial distraction below the confluence of sinuses with craniovertebral junction decompression effectively increases intracranial and PCF volumes. In most cases, this leads to decrease or complete regression of CDCT. Genesis of CDCT and associated hydrocephalus in CS is multifactorial. Thus, persistent CDCT and/or progressive hydrocephalus may occur and necessitate additional monitoring and, if necessary, neurosurgical intervention.