Postural control in Chiari I malformation: protocol for a paediatric prospective, observational cohort - potential role of posturography for surgical indication.

INTRODUCTION: Chiari I malformation (CM1) is an anatomical abnormality characterised by the cerebellar tonsils descending at least 5 mm below the foramen magnum. CM1 causes obstruction of cerebrospinal fluid (CSF) circulation as well as direct compression on the brainstem, thus causing typical consequences (syringomyelia), and typical clinical features (characteristic headaches and neurological impairment). Surgery is the only available treatment, indicated when symptomatology is present. However, sometimes patients have atypical complaints, which are often suggestive of otolaryngological (ears, nose and throat, ENT) involvement. This may be difficult for a neurosurgeon to explain. Our study aims to investigate the relationship between one of these atypical symptoms, for example, postural instability, in a paediatric population using a Computerised Dynamic Posturography (Equitest, NeuroCom, Clackamas, OR). To our knowledge, there are no previously published studies carried out on children with CM1, using dynamic posturography. METHODS AND ANALYSIS: Forty-five children aged 6-18 years old presenting with radiologically confirmed CM1 and presenting ENT clinical complaints will be included in the study for a duration of 3 years. As primary endpoint, posturographic results will be described in the population study. Second, posturographic results will be compared between patients with and without indication for surgery. Finally, preoperative and postoperative posturographic results, as well as CSF circulation quality at foramen magnum level, syringomyelia, sleep apnoea syndrome, scoliosis and behaviour will be compared in the operated patient group. ETHICS AND DISSEMINATION: This protocol received ethical approval from the Clinical Research Delegation of Nancy University Hospital, in accordance with the National Commission on Informatics and Liberties (Commission Nationale de l'Informatique et des Libertés) (protocol number 2019PI256-107). Our data treatment was in accordance with the Methodology of reference Methodology Reference-004 specification for data policy. The study findings will be disseminated via peer-reviewed publications and conference presentations, especially to the Neurosphynx's rare disease healthcare network. TRIAL REGISTRATION NUMBER: NCT04679792; Pre-results.

Case update on cranial osteopetrosis: which is the role of the neurosurgeon?

PURPOSE: Osteopetrosis (OP) is a rare skeletal disease, which can affect the skull base and calvaria. A multidisciplinary approach is mandatory and patient may need neurosurgical care. Few observations have been published, and optimal management of OP is not established yet. METHOD: We report a case of an infant with OP diagnosed at 5 months, who presented signs of intracranial hypertension associated with unilateral blindness. Bone marrow allograft was performed at 6 months of age. At neurosurgical first examination at 11 months, the child was hypotonic, with severe amblyopia; features of bicoronal synostosis were appreciated, with tense anterior fontanel bulging indicating synostotic oxycephaly. Head circumference had decreased from +3 SD to +1SD. Cerebral CT scan showed reduction of intracranial volume, inward thickening of the calvaria, bilateral stenosis of optic canal, ventricular dilatation, enlarged arachnoid spaces, and tonsillar herniation. We performed cranial vault expansion with frontal advancement and bi parietal decompression, thinning of the inner table, unroofing of the left orbit and optic canal in order to obtain optic nerve decompression. RESULTS: Postoperative course was uneventful, and the patient was discharged on day 8. Vision was unchanged but rapid improvement of axial tonus was noted. The CT scan showed satisfactory calvarial expansion with regression of tonsillar herniation. CONCLUSIONS: Neurosurgical evaluation and care are necessary in the context of a multidisciplinary approach to the patient affected by osteopetrosis. Cranial vault remodeling and expansion should be considered in patients with sign of intracranial hypertension. Timing of optic canal decompression is to be defined.