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

Chunli Lu,Longbing Ma,Jian Guan,Zhenlei Liu,Kai Wang,Wanru Duan,Zan Chen,Hao Wu,Fengzeng Jian 대한척추신경외과학회 2022 Neurospine Vol.19 No.4

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.

Phenotypes and Prognostic Factors of Syringomyelia in Single-Center Patients With Chiari I Malformation: Moniliform Type as a Special Configuration

Chunli Lu,Longbing Ma,Chenghua Yuan,Lei Cheng,Xinyu Wang,Wanru Duan,Kai Wang,Zan Chen,Hao Wu,Gao Zeng,Fengzeng Jian 대한척추신경외과학회 2022 Neurospine Vol.19 No.3

Objective: The specific association between morphometric characteristics of the syrinx and the prognosis of Chiari malformation type I (CM-I) with syringomyelia following surgical procedure seems to have not been fully elaborated. This study focused on the preoperative clinical and radiologic parameters in CM-I patients with syringomyelia to find out the relationship between the patients’ clinical status and the phenotypes of the syrinx with surgical outcome. Methods: A continuous series of pediatric and adult patients with CM-I and syringomyelia from a prospectively maintained database in a single center were included, and we explored the related factors affecting the prognosis following decompression surgery through retrospective analysis of clinical presentations, imaging characteristics, and the morphological features of syringomyelia, to provide a clinical reference for the treatment of syringomyelia. Results: There were 28 pediatric patients (13.8%), and 174 adults (86.2%) included in our study. The average Chicago Chiari Outcome Scale score was 14.56 ± 1.78. The overall prognosis after surgery was good in our series, among them 152 cases (75.25%) with a favorable prognosis, and syrinx was resolved effectively in 172 cases (85.15%). According to the univariate and multivariate analyses, the preoperative symptom duration, observation time, and with/without moniliform type were independent factors affecting the prognosis in adults. The most obvious difference between moniliform type and nonmoniliform type lies in the preoperative symptom duration, ventral subarachnoid space at the foramen magnum, and with/without straightened cervical physio-curve. Conclusion: Timely decompression surgery could achieve a better outcome in CM-I patients with syringomyelia. Moniliform syringomyelia may suggest a relatively better prognosis.

Quantitative Reduction of Basilar Invagination With Atlantoaxial Dislocation by a Posterior Approach

Jian Guan,Fengzeng Jian,Qingyu Yao,Chenghua Yuan,Can Zhang,Longbing Ma,Zhenlei Liu,Wanru Duan,Xingwen Wang,Xuefeng Bo,Zan Chen 대한척추신경외과학회 2020 Neurospine Vol.17 No.3

Objective: This study evaluated the feasibility and efficacy of quantitative reduction and fixation to treat basilar invagination (BI) with atlantoaxial dislocation (AAD). Methods: Posterior occipitocervical angle (POCA), occiput–C2 angle (Oc–C2A), clivusaxial angle (CAA), and C2–7 angle (C2–7A) were considered for quantitative reduction. Twelve patients with BI complicated with AAD received posterior interarticular release and individualized cage implantation to restore vertical dislocation. The POCA was adjusted using cantilever technology to further reduce the horizontal dislocation and adjust lower cervical vertebral angle. All patients received a radiological follow-up for ≥12 months. Improvements in spinal cord function were evaluated using Japanese Orthopedic Association (JOA) score. Results: All the patients received successful quantitative reduction for BI-AAD, and bony fusion was achieved without spinal cord injury after surgery for 12 months. The JOA score was improved significantly to 15.2 ± 0.9 twelve months after surgery (p < 0.01). Radiological follow-up revealed that individualized cage and POCA play vital roles in quantitative correction: (1) distance of the dens above McRae’s line and atlantodens interval were restored to normal level, respectively; (2) changes in Oc–C2 angle (ΔOc–C2A), C2–7 angle (ΔC2–7A), clivus-axial angle (ΔCAA), and POCA (ΔPOCA) were all caused by changes in axis tilt. Based on the changes of radiological parameter we deduced the formula for quantitative reduction by linear regression analysis: -ΔPOCA = ΔOc–C2A = -ΔC2–7A = ΔCAA. Conclusion: Quantitative posterior reduction by individualized cage and adjusting ΔPOCA is feasible for treating BI with AAD.

The Physiological Occlusion of the Central Canal May Be a Prerequisite for Syringomyelia Formation

Chuan Jiang,Xinyu Wang,Chunli Lu,Qian Li,Longbing Ma,Wei Li,Shengyu Cui,Kang Li,Xiang Wang,Yuxin Feng,Fengzeng Jian 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

Objective: Syringomyelia is a common central nervous system disease characterized by the dilation of the central canal (CC). Regarding the pathogenesis of syringomyelia, cerebrospinal fluid (CSF) circulation obstruction in the subarachnoid space (SAS) of the spinal cord has been widely accepted. However, clinical and animal studies on obstructing the CSF in SAS failed to form syringomyelia, challenging the theory of SAS obstruction. The precise pathogenesis remains unknown. Methods: We utilized an extradural compression rat model to investigate the pathogenesis underlying syringomyelia. Magnetic resonance imaging enabled detection of syringomyelia formation. To assess CSF flow within the SAS, Evans blue was infused into the cisterna magna. Histological analysis allowed morphological examination of the CC. Furthermore, CSF flow through the CC was traced using Ovalbumin Alexa-Flour 647 conjugate (OAF-647). Scanning electron microscopy (SEM) enabled visualization of ependymal cilia. Results: The findings showed that the dura mater below the compression segment exhibited lighter coloration relative to the region above the compression, indicative of partial obstruction within the SAS. However, the degree of SAS occlusion did not significantly differ between syringomyelia (SM-Y group) and those without (SM-N group). Intriguingly, hematoxylin and eosin staining and CSF tracing revealed occlusion of the CC accompanied by reduced CSF flow in the SM-Y group compared to SM-N and control groups. SEM images uncovered impairment of ependymal cilia inside the syringomyelia. Conclusion: CC occlusion may represent a physiological prerequisite for syringomyelia formation, while SAS obstruction serves to initiate disease onset. The impairment of ependymal cilia appears to facilitate progression of syringomyelia.