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. 2025 Jan;13(1):159-164.
doi: 10.1007/s43390-024-00958-0. Epub 2024 Sep 25.

Magnetic resonance imaging evaluation of the cerebellar tonsil position before and after posterior spinal fusion in adolescent idiopathic scoliosis

Bosio Santiago  1 , Carolina Halliburton  2 , Maenza Rubén  2 , Puigdevall Miguel  2
Affiliations

Magnetic resonance imaging evaluation of the cerebellar tonsil position before and after posterior spinal fusion in adolescent idiopathic scoliosis

Bosio Santiago et al. Spine Deform. 2025 Jan.

Abstract

Background: Chiari malformation type I(CM-I) is one of the most common neurological malformations observed in patients with adolescent idiopathic scoliosis (AIS). It remains uncertain whether AIS patients without neurological symptoms require CM-I decompression before undergoing spinal corrective surgery to prevent cerebellar tonsil herniation and potential neurological complications. This study aims to assess variations in the position of the cerebellar tonsil after posterior spinal fusion (PSF) in neurologically intact patients with AIS.

Methods: We retrospectively evaluated 40 patients with AIS who underwent posterior spinal fusion (PSF) without neurological symptoms. Sagittal hindbrain MRIs were performed before and after spinal surgery. The cerebellar tonsil's position relative to the foramen magnum was measured using the method described by Aboulezz (J Comput Assist Tomogr 1985). We assessed variations in the cerebellar tonsil position concerning spinal correction and elongation after PSF.

Results: The average preoperative magnitude of the scoliotic curve was 53.15 degrees (SD 10.46 degrees), and that of thoracic kyphosis was 35.42 degrees (SD 12.38 degrees). In the immediate postoperative period, the average magnitudes were 7.45 degrees (SD 7.33 degrees) and 27.87 degrees (SD 9.03 degrees), respectively. The average correction achieved with PSF was 86% in the coronal plane (p < 0.00001). The average length of the spine in the coronal plane was 44.5 cm (SD 5.25 cm) preoperatively and 48.27 cm (SD 4.40 cm) postoperatively (p < 0.00001). The average length of the vertebral column in the sagittal plane was 50.87 cm (SD 4.47 cm) preoperatively and 55.13 cm (SD 3.27 cm) postoperatively (p < 0.00001). No significant difference was observed in the position of the cerebellar tonsil in the measurements taken before and after spinal deformity correction (p = 0.6042). In 10 out of 40 patients, caudal displacement of the cerebellar tonsil was observed after PSF. In 28 patients, no variation in the position of the cerebellar tonsil was observed, and in 2, cephalic displacement was noted.

Conclusion: In AIS patients with a normal position of the cerebellar tonsil undergoing posterior spinal fusion, there is no significant change in their position after surgery. Our analysis did not reveal any correlation between curve correction, spine elongation, and variations in the cerebellar tonsil position.

Significance: The position of the cerebellar tonsil remained largely unchanged after PSF in AIS patients without neurological symptoms. Further studies would be necessary to determine whether surgical decompression is required in asymptomatic patients with CM-I before undergoing surgery to correct spinal deformity.

Keywords: Adolescent idiopathic scoliosis; Cerebellar tonsils; Chiari Malformation; Magnetic resonance imaging; Posterior spinal fusion.

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Conflict of interest statement

Declarations. Conflict of interest: All the investigators of this manuscript have no conflict of interest. Ethical approval: The conduct of this research will be carried out in compliance with the ethical principles in accordance with the regulatory standards at the national and international level, in accordance with the Resolution of the Ministry of the Nation, the Declaration of Helsinki of the World Medical Association and all its amendments and respecting the Good Clinical Practice Standards. The institutional electronic medical record of Hospital Italiano de Buenos Aires was used as a secondary basis. All study data has been treated with the utmost confidentiality anonymously, with restricted access only for personnel authorized for the purposes of the study in accordance with current legal regulations National Personal Data Protection Law 25.326 / 00 (Habeas data Law) and Law 26. 529/09. The identity of the personal data will be kept under absolute confidentiality and anonymity, only the researchers involved, and the evaluating Ethics Committee have access to them. Informed consent: The patient has consented in a separate document to the public publication of his personal data.

References

    1. Cheng JS, Nash J, Meyer GA (2002) Chiari type I malformation revisited: diagnosis and treatment. Neurologist 8(6):357–362. https://doi.org/10.1097/00127893-200211000-00005 . (PMID: 12801437) - DOI - PubMed
    1. Eule JM, Erickson MA, O’Brien MF, Handler M (2002) Chiari I malformation associated with syringomyelia and scoliosis: a twenty-year review of surgical and nonsurgical treatment in a pediatric population. Spine 27(13):1451–1455. https://doi.org/10.1097/00007632-200207010-00015 . (PMID: 12131745) - DOI - PubMed
    1. Noureldine MHA, Shimony N, Jallo GI, Groves ML (2019) Scoliosis in patients with Chiari malformation type I. Childs Nerv Syst 35(10):1853–1862. https://doi.org/10.1007/s00381-019-04309-7 . (Epub 2019 Jul 24 PMID: 31342150) - DOI - PubMed
    1. Aboulezz AO, Sartor K, Geyer CA, Gado MH (1985) Position of cerebellar tonsils in the normal population and in patients with Chiari malformation: a quantitative approach with MR imaging. J Comput Assist Tomogr 9(6):1033–1036. https://doi.org/10.1097/00004728-198511000-00005 . (PMID: 4056132) - DOI - PubMed
    1. Barkovich AJ, Wippold FJ, Sherman JL, Citrin CM (1986) Significance of cerebellar tonsillar position on MR. AJNR Am J Neuroradiol 7(5):795–799 - PubMed - PMC

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