Relationship Between Syrinx Resolution and Cervical Sagittal Realignment Following Decompression Surgery for Chiari I Malformation Related Syringomyelia Based on Configuration Phenotypes

Abstract

Objective: Combined with different configuration types of syringomyelia, to analyze the correlation between syrinx resolution and changes in cervical sagittal alignment following Foramen magnum and Magendie dredging (FMMD) for syringomyelia associated with Chiari I malformation (CM-I), and to further explore the respective relationship with clinical outcome.Methods: A consecutive series of 127 patients with CM-I and syringomyelia who underwent FMMD in our center met the inclusion criteria of this study. Their clinical records and radiologic data were retrospectively reviewed. The Japanese Orthopedic Association (JOA) scoring system and the Chicago Chiari Outcome Scale (CCOS) were used to evaluate the surgical efficacy. The phenotypes of syringomyelia and the clinical characteristics of the patients were analyzed according to grouping by cervical curvature at baseline.Results: The preoperative straight or kyphotic cervical alignment is more common in the moniliform syrinx. After surgery, the syrinx resolution and cervical sagittal realignment in the moniliform group are more obvious, and the corresponding prognosis is relatively better. Spearman correlation analysis showed that the ΔS/C ratio (the change ratio of syrinx/cord) was positively correlated with the CCOS (p = 0.001, r = 0.897) and ΔC2–7A (the change of lower cervical angle) (p = 0.002, r = 0.560). There was also a correlation between the ΔJOA score (the change rate of the JOA score) and ΔC2–7A (p = 0.012, r = 0.467).Conclusion: After decompression surgery, syrinx resolution may coexist with the changes in the subaxial lordosis angle, especially for syrinx in moniliform type, and the relationship between syrinx resolution and cervical sagittal realignment might be valuable for evaluating the surgical outcome.

Individualized Functional Decompression Options for Adult Chiari Malformation With Syringomyelia and A Novel Scale for Syringomyelia Resolution: A Single-Center Experience

“…Moreover, especially with the “advantage” of publication bias, more invasive surgeries seem to have trends to resolve the syrinx better. However, there is no standardized measurement method for syringomyelia resolution, and most previous studies have focused on describing the syrinx resolution at a single level [ 24 , 36 ]. Thus, we used the three-dimensional volume changes of cervical syringomyelia to indicate the syringomyelia resolution.…”

Correlation Among Syrinx Resolution, Cervical Sagittal Realignment, and Surgical Outcome After Posterior Reduction for Basilar Invagination, Atlantoaxial Dislocation, and Syringomyelia

“…17 A straight cervical spine is indicated by a negative value within this range, a positive value indicates kyphosis, and a negative value outside of this range indicates hyperlordosis. 18 The horizontal distance between the C2 plumb line and the posterosuperior point of the C7 body is known as the C2-7 sagittal vertical axis (C2-7SVA). T1 slope: the included angle between the horizontal line and the top endplate of T1.…”

“…The syrinx/cord ratio (S/C ratio) represented the ratio of the spinal cord diameter at the same level to the syrinx diameter. 18 The formula (preoperative value À postoperative value)/(preoperative value) was used to determine the resolution rate of S/C. 18 The angle between 2 lines that run down the ventral side of the medulla oblongata and the upper cervical spinal cord on sagittal MRI images is known as the cervicomedullary angle (CMA).…”

“…18 The formula (preoperative value À postoperative value)/(preoperative value) was used to determine the resolution rate of S/C. 18 The angle between 2 lines that run down the ventral side of the medulla oblongata and the upper cervical spinal cord on sagittal MRI images is known as the cervicomedullary angle (CMA). McRae line level about ventral subarachnoid space (SAS) and dorsal SAS at the foramen magnum: SAS at foramen magnum (FM) = ventral SAS + dorsal SAS.…”