preprints.org > medicine and pharmacology > neuroscience and neurology > doi: 10.20944/preprints202311.1626.v1

Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Version 1 : Received: 24 November 2023 / Approved: 24 November 2023 / Online: 27 November 2023 (11:39:57 CET)

Introduction- Chiari malformation type 1 (CM-1) is defined by the caudal displacement of cerebellar tonsils through the foramen magnum (cut off of 5 mm from McRae line.) In Chiari malformation type 1.5 (CM-1.5) both cerebellar tonsils and brainstem result herniated. Patient with CM may exhibit a variety of symptoms: the most common are headache and cervical pain. Associated anomalies such as syringomyelia (67-80%), hydrocephalus (10 %), craniosynostosis or tethered spinal cord may be present. Surgical treatment is not performed in asymptomatic patients, while the presence of syringomyelia represents an indication for surgical decompression. In this paper we report our experience with the use of intra-operative ultrasonography in orienting surgical decompression with or without dural opening. Methods- We retrospectively examined and selected pediatric patients with CM-1/ CM-1.5 who were managed between 2006-2020 at Giannina Gaslini Hospital. Exclusion criteria were the association with achondroplasia and with spina bifida. Results- A total of 211 pediatric patients were identified for evaluation: CM-1 accounted for 83.9% of patients and CM-1.5 for 16.1%. Syringomyelia was associated in 28.4% of cases and hydrocephalus in 8%. According to findings at the intra-operative ultrasonography, a bony and ligamentous decompression alone was sufficient in 59.8% patients, a simple opening of dura mater was performed in 3% and a duraplasty in 27.1%. Seven patients experience post-operative complications, and 3 patients needed a second surgical operation for insufficient decompression, found at follow-up. Discussion and conclusion- The standard surgical treatment of CM-1/ CM-1.5 consists in decompression of posterior cranial fossa. Whether to perform a simple bony decompression or to associate the opening of the dura mater with duraplasty has always been controversial in pediatric population. Our case series, where good radiological findings were achieved with a limited number of reoperations, shows how intra-operative ultrasound may be a real-time helpful tool in orienting the surgical strategy, if we consider as surgical endpoint the restoration of cerebrospinal fluid (CSF) flux. However, there is the need to standardize this method, using quantitative variables.

Chiari malformation; syringomyelia; posterior fossa decompression; duraplasty

Medicine and Pharmacology, Neuroscience and Neurology

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