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Zisakis A, Sun R, Pepper J, Tsermoulas G. Chiari Malformation Type 1 in Adults. Adv Tech Stand Neurosurg 2023; 46:149-173. [PMID: 37318574 DOI: 10.1007/978-3-031-28202-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The term Chiari malformation refers to a heterogeneous group of anatomical abnormalities at the craniovertebral junction. Chiari malformation type 1 (CM1) refers to the abnormal protrusion of cerebellar tonsils through the foramen magnum and is by far the commonest type. Its prevalence is estimated approximately 1%; it is more common in women and is associated with syringomyelia in 25-70% of cases. The prevalent pathophysiological theory proposes a morphological mismatch between a small posterior cranial fossa and a normally developed hindbrain that results in ectopia of the tonsils.In most people, CM1 is asymptomatic and diagnosed incidentally. In symptomatic cases, headache is the cardinal symptom. The typical headache is induced by Valsalva-like maneuvers. Many of the other symptoms are nonspecific, and in the absence of syringomyelia, the natural history is benign. Syringomyelia manifests with spinal cord dysfunction of varying severity. The approach to patients with CM1 should be multidisciplinary, and the first step in the management is phenotyping the symptoms, because they may be due to other pathologies, like a primary headache syndrome. Magnetic resonance imaging, which shows cerebellar tonsillar decent 5 mm or more below the foramen magnum, is the gold standard investigative modality. The diagnostic workup may include dynamic imaging of the craniocervical junction and intracranial pressure monitoring.The management of CM1 is variable and sometimes controversial. Surgery is usually reserved for patients with disabling headaches or neurological deficits from the syrinx. Surgical decompression of the craniocervical junction is the most widely used procedure. Several surgical techniques have been proposed, but there is no consensus on the best treatment strategy, mainly due to lack of high-quality evidence. The management of the condition during pregnancy, restriction to lifestyle related to athletic activities, and the coexistence of hypermobility require special considerations.
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Affiliation(s)
- Athanasios Zisakis
- Department of Neurosurgery, Queen Elizabeth Hospital Birmingham, University Hospitals of Birmingham, Birmingham, UK
| | - Rosa Sun
- Department of Neurosurgery, Queen Elizabeth Hospital Birmingham, University Hospitals of Birmingham, Birmingham, UK
| | - Joshua Pepper
- Department of Neurosurgery, Queen Elizabeth Hospital Birmingham, University Hospitals of Birmingham, Birmingham, UK
| | - Georgios Tsermoulas
- Department of Neurosurgery, Queen Elizabeth Hospital Birmingham, University Hospitals of Birmingham, Birmingham, UK.
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.
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Zhou Q, Song C, Huang Q, Li H, Yang X, Peng L, Li J, Chen L, Shi L, Qi S, Lu Y. Evaluating craniovertebral stability in Chiari malformation coexisting with Type II basilar invagination: an observational study based on kinematic computed tomography and its clinical application. World Neurosurg 2022; 164:e724-e740. [PMID: 35595047 DOI: 10.1016/j.wneu.2022.05.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/10/2022] [Accepted: 05/10/2022] [Indexed: 11/18/2022]
Abstract
BACKGROUND Treatment of Chiari malformation (CM) is controversial, especially when it coexists with "stable" or Type II basilar invagination (CM+II-BI). Precise evaluation of craniovertebral junction (CVJ) stability is crucial in such patients; however, this has never been validated. This study aimed to dynamically evaluate atlanto-condyle and atlantoaxial stability by kinematic computed tomography (CT) and report its surgical treatment. METHODS The study recruited 101 patients (control, CM, and CM+II-BI groups: 48, 34, and 19 patients, respectively). During kinematic CT, the CVJ stability-related parameters were measured and compared between the three groups. The surgical strategy for treating CM+II-BI was based on these results. Pre- and postoperative images were acquired, and functional scores were used to assess the outcome. RESULTS Among the three groups, the length of the clivus and the height of the condyle were the shortest in the CM+II-BI group, which was accompanied by the greatest rotation of the atlas and atlanto-condyle facet movement on cervical flexion and extension. Moreover, in such patients, increased Chamberlain's baseline violation indicated the aggregate invagination of the odontoid in the flexed position, and asymmetric displacement of atlantoaxial facets was observed. Seventeen CM+II-BI patients underwent surgical treatment with atlantoaxial distraction and occipitocervical fusion. The syringomyelia width and tonsillar herniation decreased significantly, and functional scores indicated symptom relief and good outcomes. CONCLUSIONS CVJ instability, especially the ultra-movement of atlanto-condyle facets, commonly exists in II-BI as evaluated using kinematic CT. The surgical strategy of atlantoaxial distraction and occipitocervical fusion should be considered to treat such patients.
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Affiliation(s)
- Qiang Zhou
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Neurology Research Institution, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Chong Song
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qinguo Huang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Hong Li
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Neurology Research Institution, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoyu Yang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Lin Peng
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Neurology Research Institution, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Junjie Li
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Neurology Research Institution, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Lei Chen
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Neurology Research Institution, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Linyong Shi
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Songtao Qi
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Neurology Research Institution, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Glioma Center, Guangzhou, China
| | - Yuntao Lu
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Neurology Research Institution, Nanfang Hospital, Southern Medical University, Guangzhou, China; Nanfang Glioma Center, Guangzhou, China.
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Goel A, Vutha R, Shah A, Ranjan S, Jadhav N, Jadhav D. Atlantoaxial fixation for failed foramen magnum decompression in patients with Chiari formation. JOURNAL OF CRANIOVERTEBRAL JUNCTION AND SPINE 2020; 11:186-192. [PMID: 33100768 PMCID: PMC7546052 DOI: 10.4103/jcvjs.jcvjs_113_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 07/20/2020] [Indexed: 12/05/2022] Open
Abstract
Background: Relationship of atlantoaxial instability with Chiari formation is further analyzed in the report. Objective: The outcome of 25 patients who had failed conventional treatment for Chiari formation that included foramen magnum decompression surgery and were treated by atlantoaxial fixation is analyzed. Materials and Methods: During the period January 2010 to November 2019, we treated 25 patients who had undergone conventionally described surgical procedures; all included foramen magnum decompression for Chiari formation. None of the patients had any craniovertebral junction anomaly. All patients had syringomyelia. All patients had worsened in their neurological condition following surgery either in the immediate or in the delayed postoperative phase. Atlantoaxial instability was diagnosed on the basis of facetal alignment and on the basis of direct observation of joint status by bone manipulation during surgery. The patients were treated by atlantoaxial fixation. Goel clinical grading scale and Japanese Orthopedic Association Score assessed the clinical status both before and after surgery. Results: Following surgery, all patients improved in the clinical condition. The improvement began in the immediate postoperative period and progressed. During the follow-up period that ranged from 4 to 123 months, “significant” neurological recovery and amelioration of presenting symptoms were observed. During the period of follow-up, reduction in the size of syrinx was observed in 14 out of 18 cases where postoperative magnetic resonance imaging was possible. Conclusions: Clinical results reinforce the belief that atlantoaxial instability is the nodal point of pathogenesis of Chiari formation. Atlantoaxial fixation is the treatment.
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Affiliation(s)
- Atul Goel
- Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Mumbai, Maharashtra, India
| | - Ravikiran Vutha
- Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Mumbai, Maharashtra, India
| | - Abhidha Shah
- Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Mumbai, Maharashtra, India
| | - Shashi Ranjan
- Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Mumbai, Maharashtra, India
| | - Neha Jadhav
- Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Mumbai, Maharashtra, India
| | - Dikpal Jadhav
- Department of Neurosurgery, K.E.M. Hospital and Seth G.S. Medical College, Mumbai, Maharashtra, India
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Chiari malformation type I and basilar invagination originating from atlantoaxial instability: a literature review and critical analysis. Acta Neurochir (Wien) 2020; 162:1553-1563. [PMID: 32504118 PMCID: PMC7295832 DOI: 10.1007/s00701-020-04429-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/22/2020] [Indexed: 12/27/2022]
Abstract
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 1 Formation Redefined-Clinical and Radiographic Observations in 388 Surgically Treated Patients. World Neurosurg 2020; 141:e921-e934. [PMID: 32562905 DOI: 10.1016/j.wneu.2020.06.076] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The subject of Chiari formation is revisited and redefined. Results of surgical treatment of patients with Chiari formation by atlantoaxial fixation are presented. METHODS Results were analyzed of 388 patients with Chiari formation surgically treated during 2010 to June 2019. RESULTS Two hundred and sixty-six patients had syringomyelia. Two hundred and three patients had no craniovertebral bone abnormality and 74 patients had group A and 111 patients had group B basilar invagination. Twenty-nine patients had been earlier treated by foramen magnum decompression surgery with or without duroplasty. Clinical parameters, analysis of video recordings both before and after surgery, and patient self-assessment were included in the analysis of outcome. Immediate postoperative and sustained clinical improvement was observed in 385 patients (99.4%). CONCLUSIONS Satisfactory clinical outcome in most patients after atlantoaxial fixation and without any manipulation of neural structures, dura, or bone in the region of foramen magnum consolidates the viewpoint that atlantoaxial instability is the nodal point of pathogenesis of Chiari 1 formation. The study suggests that Chiari 1 formation may be a secondary natural neural alteration in the face of atlantoaxial instability. The role of foramen magnum decompression surgery needs to be reassessed.
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Joaquim AF. Severe Cerebellar Degeneration and Chiari I Malformation - Speculative pathophysiology based on a systematic review. Rev Assoc Med Bras (1992) 2020; 66:375-379. [PMID: 32520161 DOI: 10.1590/1806-9282.66.3.375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 10/10/2019] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Symptomatic Chiari Type I Malformation (CM) is treated with posterior fossa decompression with or without duroplasty. We have noticed some cases with concomitant severe cerebellar ataxia due to cerebellar atrophy. The aim of this study is to review the literature of CM associated with severe cerebellar atrophy and discuss its potential physiopathology. METHODS A systematic literature review in the Pubmed Database was performed using the following key-terms: "cerebellar atrophy Chiari", and "cerebellar degeneration Chiari". Articles reporting the presence of cerebellar degeneration/atrophy associated with CM were included. RESULTS We found only six studies directly discussing the association of cerebellar atrophy with CM, with a total of seven cases. We added one case of our own practice for additional discussion. Only speculative causes were described to justify cerebellar atrophy. The potential causes of cerebellar atrophy were diffuse cerebellar ischemia from chronic compression of small vessels (the most mentioned speculative cause), chronic raised intracranial pressure due to CSF block, chronic venous hypertension, and association with platybasia with ventral compression of the brainstem resulting in injury of the inferior olivary nuclei leading to mutual trophic effects in the cerebellum. Additionally, it is not impossible to rule out a degenerative cause for cerebellar atrophy without a causative reason. CONCLUSIONS Severe cerebellar atrophy is found in some patients with CM. Although chronic ischemia due to compression is the most presumed cause, other etiologies were proposed. The real reasons for cerebellar degeneration are not known. Further studies are necessary.
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