The changes of syrinx volume after posterior reduction and fixation of basilar invagination and atlantoaxial dislocation with syringomyelia

Wang, Zuowei; Wang, Xingwen; Jian, Fengzeng; Zhang, Can; Wu, Hao; Chen, Zan

doi:10.1007/s00586-016-4740-9

Cited by 13 publications

(13 citation statements)

References 31 publications

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“…Widely used surgical treatments aim to relieve the pressure on the medulla and cervical spinal cord and maintain or reconstruct atlantoaxial stability [ 3 , 5 ]. In 2004, Goel [ 6 ] reported that implanting a lateral joint fusion cage achieved good results in treating BI-AAD.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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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.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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“…The reason for postoperative improvement should thus be attributed in large part to the reduction, which indirectly decompresses the brain stem by a protruding odontoid, and partially in the stabilization, which serves to sustain this effect. This hypothesis was proposed by other authors [71,83,92]. Wang et al analyzed the reduction of syrinx volume and CVJ alignment in 71 patients treated with OCF and bony suboccipital decompression after reduction.…”

Section: Basilar Invagination-discussion Of Evidencementioning

confidence: 85%

“…Wang et al analyzed the reduction of syrinx volume and CVJ alignment in 71 patients treated with OCF and bony suboccipital decompression after reduction. They found that for 93.0% of patients with satisfying reposition of the odontoid, a syrinx regression was achieved as well [92]. In a recent study, Salunke and colleagues reduced and fused 38 patients with CM and BI, of which 91.9% maintained both clinical and radiographical improvement after 6 months [83].…”

Section: Basilar Invagination-discussion Of Evidencementioning

confidence: 96%

“…The evolution of BI treatment has seen considerable advances within the recent decades, although not without controversies [15,19,20,38,55,60,61,71,73,74,85]. While it is equivocally agreed upon that incidental findings warrant conservative management, a consensus on a treatment algorithm for a progressive clinical deterioration has yet to be established, which may be owed to the diversity of CVJ abnormalities and their mutual interactions [58,92].…”

Section: Basilar Invagination-current Treatment Paradigmmentioning

confidence: 99%

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Chiari malformation type I and basilar invagination originating from atlantoaxial instability: a literature review and critical analysis

et al. 2020

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Introduction Recently, a novel hypothesis has been proposed concerning the origin of craniovertebral junction (CVJ) abnormalities. Commonly found in patients with these entities, atlantoaxial instability has been suspected to cause both Chiari malformation type I and basilar invagination, which renders the tried and tested surgical decompression strategy ineffective. In turn, C1-2 fusion is proposed as a single solution for all CVJ abnormalities, and a revised definition of atlantoaxial instability sees patients both with and without radiographic evidence of instability undergo fusion, instead relying on the intraoperative assessment of the atlantoaxial joints to confirm instability. Methods The authors conducted a comprehensive narrative review of literature and evidence covering this recently emerged hypothesis. The proposed pathomechanisms are discussed and contextualized with published literature. Conclusion The existing evidence is evaluated for supporting or opposing sole posterior C1-2 fusion in patients with CVJ abnormalities and compared with reported outcomes for conventional surgical strategies such as posterior fossa decompression, occipitocervical fusion, and anterior decompression. At present, there is insufficient evidence supporting the hypothesis of atlantoaxial instability being the common progenitor for CVJ abnormalities. Abolishing tried and tested surgical procedures in favor of a single universal approach would thus be unwarranted.

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“…Chiari malformations (CM), associated with a reduced volume of the posterior fossa, are typically treated with foramen magnum decompression (FMD) (i.e., to enlarge the posterior fossa volume). [4,9,10] When CM are combined with atlantoaxial dislocation (AAD) and basilar invagination (BI), the posterior fossa volume is even further reduced; the instability requires C1–C2 distraction, realignment, and arthrodesis. [1,5-7,10] The fixation per se is likely to relieve anterior cervicomedullary compression and increase the overall posterior fossa volume.…”

Section: Introductionmentioning

confidence: 99%

Foramen magnum decompression without bone removal: C1–C2 posterior fixation for Chiari with congenital atlantoaxial dislocation/basilar invagination

Salunke

Karthigeyan

Malik

2019

Surgical Neurology International

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Background: Atlantoaxial dislocation (AAD) and basilar invagination (BI) may coexist with Chiari malformations (CM) and a small posterior fossa volume. These are typically treated with craniovertebral junction fusion and foramen magnum decompression (FMD). Here, we evaluated whether C1–C2 posterior reduction and fixation (which possibly opens up the ventral foramen magnum) would effectively treat AAD and CM without additionally performing FMD. Methods: This is a retrospective analysis of 38 patients with BI, AAD, and CM who underwent C1–C2 posterior reduction and fusion without FMD. Baseline and follow-up clinical, demographic, and radiological data were evaluated. Results: The vast majority of patients (91.9%) improved both clinically and radiographically following C1–C2 fixation alone; none later required direct FMD. Notably, AAD was irreducible in 25 (65.8%) patients. Preoperatively, syringomyelia was present in 28 (73.7%) patients and showed resolution. In 3 (8.1%) patients, resolution of syrinxes did not translate into clinical improvement. Of interest, 5 patients who sustained inadvertent dural lacerations exhibited transient postoperative neurological worsening. Conclusions: Posterior C1–C2 distraction and fusion alone effectively treated AAD, BI, accompanied by CM. The procedure sufficiently distracted the dens, reversed dural tenting, and restored the posterior fossa volume while relieving ventral brainstem compression making FMD unnecessary. Surgeons should, however, be aware that inadvertent dural lacerations might contribute to unwanted neurological deterioration.

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The changes of syrinx volume after posterior reduction and fixation of basilar invagination and atlantoaxial dislocation with syringomyelia

Abstract: Posterior reduction and fixation of the AAD and BI can effectively enlarge the foramen magnum, improve the cerebrospinal fluid circulation and consequently reduce the volume of the syrinx.

Cited by 13 publications

References 31 publications

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

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

Chiari malformation type I and basilar invagination originating from atlantoaxial instability: a literature review and critical analysis

Foramen magnum decompression without bone removal: C1–C2 posterior fixation for Chiari with congenital atlantoaxial dislocation/basilar invagination

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