# Efficacy of neurosurgical intervention in syrinx resolution in patients presenting with Chiari malformation type I and syringomyelia: a systematic review and radiological meta-analysis

## TL;DR

This study compares the effectiveness of different neurosurgical procedures in reducing syrinx size in patients with Chiari malformation type I and syringomyelia.

## Contribution

The study provides a systematic review and radiological meta-analysis comparing the efficacy of neurosurgical techniques for syrinx resolution in CM1 patients.

## Key findings

- Posterior fossa decompression with duraplasty significantly reduced syrinx width, length, and syrinx-to-cord ratio.
- Posterior fossa decompression with tonsillar reduction showed modest superiority in syrinx resolution compared to duraplasty.
- Fourth ventricular stents and syringo-subarachnoid shunts lacked sufficient data for formal analysis.

## Abstract

Neurosurgical techniques have been used to treat Chiari Malformation type 1 (CM1). However, there remains some uncertainty regarding which neurosurgical procedure is most efficacious in treating patients with CMI and syringomyelia. Our study aims to compare the efficacy of available neurosurgical techniques in resolving syrinx for patients with CM1 and syringomyelia. Included studies must report both pre-and post-operative syrinx measurements, discuss the use of nurosurgery, and involve patients with CM1 and syringomyelia. Studies with less than 5 patients were excluded. Databases used to identify studies included PubMed, Scopus, Cochrane Library, Web of Science, and Ovid. The Newcastle-Ottawa Scale, Joanna Briggs Institute checklist, and the Risk of Bias 2 analysis tools assesed the risk of bias in the study. A meta-analysis was conducted using a random-effects model, and forest plots illustrated the results. A total of 20 studies involving 3,063 patients with CM1 and syringomyelia were included in the study. Posterior fossa decompression with duraplasty (PFDD) demonstrated significant syrinx reduction: syrinx width (SW) reduced by a mean difference (MD) of 2.46 mm (95% CI: 2.16–2.76), syrinx length by 1.68 vertebral segments (95% CI: 1.44–1.92), and syrinx-to-cord ratio by 0.21( 95% CI: 0.15 to 0.26). Posterior fossa decompression with tonsillar reduction (PFDTR) had significantly reduced SW (MD: 2.85 mm, 95% CI: 1.99–3.71). It was superior to PFDD in the syrinx-to-cord ratio (MD: 0.04, 95% confidence interval (CI) of 0.01 to 0.08). Fourth ventricular stents (FVS) and syringo-subarachnoid shunts (SSS) were other reported techniques, but there were insufficient studies for formal analysis. PFDD and PFDRT are both efficacious in reducing syrinx size in patients with CM1 and syringomyelia. PDRT displayed modest superiority in syrinx resolution, and the clinical significance of this is limited. More studies are needed to determine the efficacy of FVS and SSS.

The online version contains supplementary material available at 10.1007/s10143-025-03864-9.