成人Chiari畸形Ⅰ型后颅窝线性容积特征与小脑扁桃体下疝程度和脊髓空洞的相关性分析

目的 :探讨成人Chiari畸形Ⅰ型(Chiari malformation typeⅠ,CMⅠ)患者后颅窝线性容积特征及其与脊髓空洞和小脑扁桃体下疝程度之间的相关性。方法:收集2010年6月~2014年6月在我院接受治疗的CMⅠ患者,入选标准为:(1)年龄30岁;(2)经头颈部MRI确诊为CMⅠ伴或不伴脊髓空洞;所有入选患者均排除颅内占位性病变、颅骨破坏、后颅窝手术史或获得性Chiari畸形。选取年龄匹配的正常成人作为对照组,测量两组头颅正中矢状位MRI中斜坡长度、枕骨大孔横径、枕上长度、后颅窝矢状径、后颅窝高径和后颅窝斜坡倾斜角α等指标,并将两组按性别分组后比较后颅窝线性容积差异。同时根据小脑扁桃体下疝程度及是否伴发脊髓空洞进行分组,分析后颅窝线性容积特征与小脑扁桃体下疝程度及脊髓空洞的关系。结果:共纳入CMⅠ患者37例,男18例,女19例;年龄38.5±5.5岁(31~56岁)。正常对照组41例,男19例,女22例;年龄36.4±6.3岁(33~58岁),成人CMⅠ患者后颅窝斜坡长度、枕上长度、后颅窝矢状径、后颅窝高径及斜坡倾斜角分别为35.9±4.2mm、38.2±5.8mm、77.4±6.1mm、28.2±3.9mm和47.4°±6.4°,均明显小于正常对照组(43.3±2.9mm、43.5±5.6mm、82.5±4.5mm、35.4±3.4mm、58.6°±5.7°,P0.05);伴脊髓空洞的成人CMⅠ组患者斜坡倾斜角(45.8°±7.6°)较单纯CMⅠ组(49.7°±5.1°)显著减小;Ⅱ度扁桃体下疝CMⅠ患者的后颅窝斜坡长度(31.4±3.6mm)及倾斜角(42.3°±5.4°)明显小于Ⅰ度扁桃体下疝CMⅠ患者(36.2±3.8mm、48.1°±5.2°;P0.05),余指标未见明显差异。结论 :成人CMⅠ患者的后颅窝容积明显减少,但与脊髓空洞和扁桃体下疝程度之间无显著相关性;CMⅠ患者斜坡发育不良与脊髓空洞的形成以及小脑扁桃体下疝程度存在一定相关性。     

Chiari畸形Ⅰ型患者后颅窝线性容积的MRI测量

目的:探讨Chiari畸形Ⅰ型(Chiari Malformation TypeⅠ,CMI)患者后颅窝容积与小脑扁桃体下疝程度及脊髓空洞间的相关性。方法:患者选自2003年～2010年收治的CMI患者,入选标准为:(1)年龄16～20岁,Risser征5级;(2)经头颈部MRI确诊为CMI伴或不伴脊髓空洞。入选患者均排除可致继发性CMI及颅骨破坏的相关疾病,选取年龄匹配的正常青少年作为对照组,测量两组研究对象头颈正中矢状位MRI中枕骨大孔径(AB),斜坡长度(AD),枕上长度(BC)以及后颅窝矢状径(CD)等指标,并将两组按性别分组后比较后颅窝容积差异。根据MRI影像学表现,将CMI患者按照小脑扁桃体下疝严重程度及是否伴发脊髓空洞进行分组,分析后颅窝容积与小脑扁桃体下疝程度及脊髓空洞间关系。结果:CMI患者共37例,平均年龄17.2岁,男23例(62.2%),女14例(37.8%)。对照组青少年共49例,平均年龄17.5岁,男24例(49.0%),女25例(51.0%)。CMI患者后颅窝各骨性标志间线性距离均明显小于同性别、年龄匹配对照组青少年。Ⅰ度扁桃体下疝CMI患者斜坡长度(AD)明显大于Ⅱ、Ⅲ度扁桃体下疝CMI患者,余指标未见明显差异。CMI伴脊髓空洞患者与单纯CMI患者后颅窝各骨性标志间线性距离亦未见显著性差异。结论:CMI患者存在明显的后颅窝容积减少,斜坡短小可能是促使CMI患者小脑扁桃体下疝加重的重要因素之一,而后颅窝容积减少并非脊髓空洞的主要致病因素。     

微创手术治疗Chiari Ⅰ型畸形（附102例报告）

ChiariⅠ型畸形又称小脑扁桃体下疝畸形，常合并脊髓空洞症，后颅窝减压是治疗ChiariⅠ型畸形最有效的手术方法。我科自2001年1月至2007年10月，采用微创后颅窝小骨窗减压加扁桃体切除治疗ChiariⅠ型畸形102例，效果良好，现报道如下。     

Chiari-I畸形并脊髓空洞症247例外科治疗

目的　探讨Chiari I畸形并脊髓空洞症手术治疗的适应证、手术方式及效果。方法对 2 4 7例磁共振成像 (MRI)证实的Chiari I畸形并脊髓空洞症患者的手术治疗情况进行回顾性分析。MRI征象为小脑扁桃体下疝及伴轻度脊髓空洞者 12 6例、小脑扁桃体下疝并脊髓空洞达第二颈椎(C2 )以上者 38例、小脑扁桃体下疝严重达C2 ～C3 水平并脊髓远隔节段空洞者 6 7例、小脑扁桃体下疝严重达C2 ～C3 水平脊髓空洞达C2 以上者 16例。患者分别行后颅窝减压术、后颅窝减压及脊髓空洞切开引流术、后颅窝减压及小脑扁桃体切除术、后颅窝减压加脊髓空洞切开引流及小脑扁桃体切除术。结果　出院时患者症状明显改善或改善者 197例 (79 8% ) ,无改善但病情稳定者 39例(15 8% ) ,恶化者 7例 (2 8% ) ,死亡者 4例 (1 6 % )。随访 10 7例患者 ,复查MRI脊髓空洞消失或基本消失者 78例 ,缩小者 14例 ,无改变者 15例。结论　后颅窝减压术、脊髓空洞切开引流术、小脑扁桃体切除术及其不同组合是治疗Chiari I畸形并脊髓空洞症的有效方法。     

Chiari畸形并脊髓空洞症的诊断与治疗

目的:对于Chiari畸形并脊髓空洞症治疗方法及其效果、预后进行探讨。方法:所有36例均经MR检查,单纯小脑扁桃体下疝8例,合并脊髓空洞症28例,合并颅底畸形6例,对于不合并脊髓空洞症的小脑桃体下疝患者,可采用后颅窝减压。对于小脑扁桃体下疝合并脊髓空洞症,行后颅窝减压及空洞引流术,根据临床表现及MR影像小脑扁桃体下疝的程度及空洞水平高低来决定切除上颈段椎板的阶段,一般只需做颈1~2椎板切除,8例严重小脑扁桃体下疝,临床症状明显或合并远隔节段脊髓空洞者,应在后颅窝减压的同时行小脑扁桃体切除,4例有症状、体征的脑积水患者先行脑室-腹腔分流术。28例合并脊髓空洞症,同时行空洞切开引流,其中8例严重小脑扁桃体下疝者同时行小脑扁桃体切除。结果:术后随访1年,36例病人中,32例痊愈或临床症状得以改善。2例合并颅底凹陷者术前症状严重,行后颅窝减压,术后恢复较差。结论:小脑扁桃体下疝畸形发病机理复杂,大部分作者认为是枕骨内生软骨发育不良,致后颅窝内容过度拥挤,而继发后脑组织下疝,严重的枕骨发育不良,可形成颅底凹陷并使后颅窝更加拥挤,脊髓空洞症继发于枕大孔区解剖异常,目前大家共认是Gardner的水锤效应所致。后颅窝减压术可使延-颈髓充分减压,并有效缓解临床症状。空洞切开引流及小脑扁桃体切除     

Ⅰ型Chiari畸形和(或)脊髓空洞相关脊柱侧凸术前评估和治疗选择

Ⅰ型Chiari畸形是小脑扁桃体下疝畸形,为后脑的先天性畸形,其病理特征是小脑扁桃体疝入椎管内,小脑低于枕骨大孔5mm以上。虽然非特发性脊柱侧凸中较少见的为伴发Chiari畸形和(或)脊髓空洞者,但随着诊断技术的提高,该类患者已变得不那么少见。检索Chiari畸形合并脊柱侧凸,得到相关中英文文献100篇,作者对相关文献进行综述,以了解Ⅰ型Chiari畸形合并脊柱侧凸研究进展。     

Chiari-Ⅰ畸形并脊髓空洞症247例外科治疗

目的 探讨Chiari-Ⅰ畸形并脊髓空洞症手术治疗的适应证、手术方式及效果。方法对247例磁共振成像(MRI）证实的Chiari-Ⅰ畸形并脊髓空洞症患者的手术治疗情况进行回顾性分析。MRI征象为小脑扁桃体下疝及伴轻度脊髓空洞者126例、小脑扁桃体下疝并脊髓空洞达第二颈椎(C2)以上者38例、小脑扁桃体下疝严重达C2～C3水平并脊髓远隔节段空洞者67例、小脑扁桃体下疝严重达C2～C3水平脊髓空洞达C2以上者16例。患者分别行后颅窝减压术、后颅窝减压及脊髓空洞切开引流术、后颅窝减压及小脑扁桃体切除术、后颅窝减压加脊髓空洞切开引流及小脑扁桃体切除术。结果 出院时患者症状明显改善或改善者197例(79．8％)，无改善但病情稳定者39例(15．8％)，恶化者7例(2．8％)，死亡者4例(1．6％)。随访107例患者，复查MRI脊髓空洞消失或基本消失者78例，缩小者14例，无改变者15例。结论 后颅窝减压术、脊髓空洞切开引流术、小脑扁桃体切除术及其不同组合是治疗Chiari-Ⅰ畸形并脊髓空洞症的有效方法。     

Chiari畸形/脊髓空洞合并脊柱侧凸的病理机制及治疗研究进展

Chiari畸形是一种以小脑扁桃体下疝为主要特征的先天性神经系统疾病,主要病理特征表现为小脑扁桃体下降至枕骨大孔水平以下,疝入椎管内致后脑诸结构、脑干、小脑及后组颅神经受挤压或者牵拉导致的一系列功能障碍。流行病学研究显示Chiari畸形发病率约为1%,其中50%~75%的Chiari畸形患者合并存在脊髓空洞。而脊柱     

Chiari畸形后路减压手术术后近期并发症分析

Arnold Chiari畸形（Arnold Chiari malformation，ACM），也称小脑扁桃体下疝畸形,是一种以小脑扁桃体下疝人枕骨大孔为特征的先天性畸形。Chiari畸形的手术目的是解除颈枕部组织对脊髓的压迫，恢复正常的脑脊液动力学，缓解脊髓空洞。我院1998年1月～2006年6月共手术治疗Chiari畸形154例，对术后1个月内出现的各种并发症进行总结，报告如下。     

特发性脊柱侧凸患者小脑扁桃体位置与后颅窝容积关系的影像学观察

目的:比较特发性脊柱侧凸(idiopathic scoliosis,IS)患者与年龄匹配的非脊柱畸形患者后颅窝容积的差异,探讨IS患者后颅窝发育异常与小脑扁桃体生理性下疝的关系。方法:从2009年1月至2011年6月我科收治的500例IS患者中选取70例年龄16～20岁、Risser征5级、术前行站立位全脊柱正侧位X线片及颈枕部MRI检查的患者为研究对象(A组),男48例,女22例,侧凸平均Cobb角51.2°±14.1°。选取年龄匹配的58例非脊柱畸形患者作为对照组(B组),男27例,女31例。测量两组研究对象头颈正中矢状位MRI中小脑扁桃体下缘超出枕骨大孔连线(AB线)的距离(d值)、枕骨大孔前后径(AB)、斜坡长度(AD)、枕上长度(BC)以及后颅窝矢状径(CD),比较两组小脑扁桃体位置及后颅窝容积差异。根据MRI表现,将IS组患者分为伴生理性小脑扁桃体下疝组(A1组)和不伴生理性小脑扁桃体下疝组(A2组),分析后颅窝容积与小脑扁桃体生理性下疝间关系及主弯Cobb角与小脑扁桃体生理性下疝程度的相关性。结果:A组d值和枕骨大孔前后径明显大于B组(P<0.05),而AD、BC以及CD均明显小于B组(P<0.05)。A组患者d值与主弯Cobb角无显著相关性(P>0.05),其生理性小脑扁桃体下疝发生率为22.9%,A1组患者BC显著小于A2组患者(P<0.05),AB、AD、CD两组间均无显著性差异(P>0.05)。结论:IS患者小脑扁桃体位置低可能与其后颅窝枕骨大孔增大而斜坡、枕骨发育受限有关,IS患者成骨异常可能也影响到了其后颅窝发育。     

Analysis of the posterior fossa in children with the Chiari 0 malformation

OBJECTIVE: We previously reported the resolution of syringohydromyelia without cerebellar tonsillar ectopia in five patients after posterior fossa decompression of the so-called Chiari 0 malformation. A sixth patient is described. In this study, the anatomy of the posterior fossa is analyzed using radiological imaging, enabling features of the posterior fossa in this uncommon subgroup of children to be characterized. METHODS : Multiple measurements were made on magnetic resonance imaging studies in six children with Chiari 0 malformation to determine the position of the brainstem relative to the foramen magnum. Fifty children with normal magnetic resonance imaging studies of the brain were used as controls. RESULTS: All children with a Chiari 0 malformation were found to have the following positive results: obices that were located more than 2 standard deviations below normal, an increase in the anteroposterior midsagittal distance of the spinomedullary junction at the level of the foramen magnum, an increase in the angle between the floor of the fourth ventricle and clivus, and an increase in the anteroposterior midsagittal distance of the foramen magnum. CONCLUSION: The findings of this study suggest that the contents of the posterior fossa are indeed compromised and/or distorted in patients with syringohydromyelia but no tonsillar ectopia. In this group, the brainstem was caudally displaced more than 3 standard deviations below normal.     

青少年特发性脊柱侧凸患者颅颈交界处的脑脊液动力学特征的MR比较研究

目的 本研究旨在明确青少年特发性脊柱侧凸(AIS)患者颅颈交界处是否亦存在脑脊液阻塞及其与小脑扁桃体位置、枕骨大孑L大小及体表皮层诱发电位异常的相关性.方法 对30例AIS和30例年龄、性别匹配的正常对照组进行常规和相位对比法核磁共振检查.在枕骨大孑L处蛛网膜下腹侧和背侧分别选择4个兴趣Ⅸ测量两组的脑脊液流动峰值速度.在正中矢状面上测量小脑扁桃体相对枕骨大孔连线的位置,枕骨大孔前后径、横径以及面积.将测量参数与体表皮层诱发电位进行相关性分析.结果 AIS患者枕骨大孔处脑脊液流动速度峰值与正常对照组差异无统计学意义.尽管AIS患者中有50％的小脑扁桃体低于枕骨大孔连线1 mm且位置明显低于正常对照组,其枕骨大孔的前后径及面积明显大于正常对照组,小脑扁桃体位置和枕骨大孔面积呈明显负相关.体表皮层诱发电位止常和异常的AIS患者脑脊液流速以及枕骨大孔形态均无明显差异.结论 尽管A1S患者存在低位小脑扁桃体,但其枕骨大孔处脑脊液流动并无明显阻塞,这可能是山于小脑扁桃体位置越低者其枕骨大孔越大而产生的中和代偿结果.AIS患者的体表皮层诱发电位异常亦与其枕骨大孔处的脑脊液流动无相关性.     

Chiari type I malformations in adults: a morphometric analysis of the posterior cranial fossa

OBJECTIVE: Chiari type I malformation (CMI) is a congenital disorder characterized by caudal displacement of the cerebellar tonsils through the foramen magnum into the spinal canal. Recent studies suggest that overcrowding in the posterior cranial fossa (PCF) because of underdeveloped bony structures in the intrauterine life is the main cause of this malformation. For this reason, the authors want to contribute to the current literature, which focuses on bone abnormalities in the PCF in patients with CMIs. METHODS: We examined a retrospective cohort of 60 adult patients with CMIs, and multiple measurements were made on magnetic resonance imaging. The results were compared to 30 healthy adult control subjects. Mann-Whitney U test was used as a statistical method. RESULTS: All measurements except mean anteroposterior diameter of the foramen magnum were reduced in patients compared to control. An increase in the anteroposterior mid-sagittal distance of the foramen magnum in patients reached statistically significant difference compared to control. All patients had tonsillar herniation at least 5 mm below the plane of the foramen magnum. Chiari type I malformation in this study was associated with syringomyelia in 46 patients. CONCLUSION: This study with a limited number of patients suggests that the bony components of the PCF are not developed fully, supporting the current concept that CMI is a disorder of the para-axial mesoderm.     

Foramen magnum decompression for syringomyelia associated with basilar impression and Chiari I malformation--report of three cases.

Anterior or posterior decompression of the foramen magnum was performed in three patients with syringomyelia associated with basilar impression and Chiari I malformation. The operative results were evaluated using the pre- and postoperative magnetic resonance (MR) images. Two patients with combined anterior and posterior cervicomedullary compression due to basilar impression and tonsillar descent received suboccipital craniectomy, upper cervical laminectomy, and dural plasty without any intradural manipulations via the posterior approach. One patient with prominent anterior cervicomedullary compression due to basilar impression and a sharp clivoaxial angle was operated on by the transoral anterior approach. Postoperatively, all patients showed a sustained shrinkage of the syrinx and rounding of the flattened cerebellar tonsils. Two patients showed upward movement of the herniated tonsils. All patients had improved symptoms during 2-4 years follow-up. Treatment of syringomyelia associated with basilar impression and Chiari I malformation requires more efficient decompressive procedures at the foramen magnum based on neurological and MR findings.     

Elucidating the pathophysiology of syringomyelia.

OBJECT: Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy. METHODS: The authors prospectively studied 20 adult patients with both Chiari I malformation and symptomatic syringomyelia. Testing before surgery included the following: clinical examination; evaluation of anatomy by using T1-weighted magnetic resonance (MR) imaging; evaluation of the syrinx and cerebrospinal fluid (CSF) velocity and flow by using phase-contrast cine MR imaging; and evaluation of lumbar and cervical subarachnoid pressure at rest, during the Valsalva maneuver, during jugular compression, and following removal of CSF (CSF compliance measurement). During surgery, cardiac-gated ultrasonography and pressure measurements were obtained from the intracranial, cervical subarachnoid, and lumbar intrathecal spaces and syrinx. Six months after surgery, clinical examinations, MR imaging studies, and CSF pressure recordings were repeated. Clinical examinations and MR imaging studies were repeated annually. For comparison, 18 healthy volunteers underwent T1-weighted MR imaging, cine MR imaging, and cervical and lumbar subarachnoid pressure testing. Compared with healthy volunteers, before surgery, the patients had decreased anteroposterior diameters of the ventral and dorsal CSF spaces at the foramen magnum. In patients, CSF velocity at the foramen magnum was increased, but CSF flow was reduced. Transmission of intracranial pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was partially obstructed. Spinal CSF compliance was reduced, whereas cervical subarachnoid pressure and pulse pressure were increased. Syrinx fluid flowed inferiorly during systole and superiorly during diastole on cine MR imaging. At surgery, the cerebellar tonsils abruptly descended during systole and ascended during diastole, and the upper pole of the syrinx contracted in a manner synchronous with tonsillar descent and with the peak systolic cervical subarachnoid pressure wave. Following surgery, the diameter of the CSF passages at the foramen magnum increased compared with preoperative values, and the maximum flow rate of CSF across the foramen magnum during systole increased. Transmission of pressure across the foramen magnum to the spinal subarachnoid space in response to jugular compression was normal and cervical subarachnoid mean pressure and pulse pressure decreased to normal. The maximum syrinx diameter decreased on MR imaging in all patients. Cine MR imaging documented reduced velocity and flow of the syrinx fluid. Clinical symptoms and signs improved or remained stable in all patients, and the tonsils resumed a normal shape. CONCLUSIONS: The progression of syringomyelia associated with Chiari I malformation is produced by the action of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. This creates enlarged cervical subarachnoid pressure waves that compress the spinal cord from without, not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to syrinx progression. The disappearance of the abnormal shape and position of the tonsils after simple decompressive extraarachnoidal surgery suggests that the Chiari I malformation of the cerebellar tonsils is acquired, not congenital. Surgery limited to suboccipital craniectomy, C-I laminectomy, and duraplasty eliminates this mechanism and eliminates syringomyelia and its progression without the risk of more invasive procedures.     

青少年特发性脊柱侧凸患者颅颈交界区脑脊液动力学研究

目的探讨青少年特发性脊椎侧凸（adolescentidiopathicscoliosis,AIS）患者颅颈交界区脑脊液动力学异常与小脑扁桃体位置及枕骨大孔前后径的关系。方法用磁共振对比检测32例AIS患者及30例正常人,计算脑脊液头端流向尾端即向下（downflow,DF）时相持续时间,尾端流向头端即向上（upflow,UF）时相持续时间,二者在脑脊液循环时间内所占比率（DF比率及UF比率）,DF流动的起始时间（downflowstartpoint,DS）比率,静止期（stationary．phase,SP）比率,脑脊液向下流动最大流速（VDmax）,向上流动最大流速（VDmax）,绘制最大流速／时问曲线。测量小脑扁桃体相对枕骨大孔连线位置及枕骨大孔前后径。结果侧凸组与对照组相比,DS比率及SP比率明显增高,DF比率明显减低,枕骨大孔前后径明显增大,差异有统计学意义（P〈0．05）;UF比率、VDmax、及VDmax、差异无统计意义（P〉0．05）。侧凸组56．3％小脑扁桃体位置低于枕骨大孔连线。结论AIS患者存在颅颈交界区脑脊液动力学改变,考虑与脊柱脊髓生长不平衡导致脊髓牵拉,小脑扁桃体下移有关。枕骨大孔虽发生适应性增大,但仍不能完全代偿。     

Is there a morphometric cause of Chiari malformation type I? Analysis of existing literature

Although many etiologies have been proposed for Chiari malformation type I (CM-I), there currently is no singular known cause of CM-I pathogenesis. Advances in imaging have greatly progressed the study of CM-I. This study reviews the literature to determine if an anatomical cause for CM-I could be proposed from morphometric studies in adult CM-I patients. After conducting a literature search using relevant search terms, two authors screened abstracts for relevance. Full-length articles of primary morphometric studies published in peer-reviewed journals were included. Detailed information regarding methodology and symptomatology, craniocervical instability, syringomyelia, operative effects, and genetics were extracted. Forty-six studies met inclusion criteria, averaging 93.2 CM-I patients and 41.4 healthy controls in size. To obtain measurements, 40 studies utilized MRI and 10 utilized CT imaging, whereas 41 analyzed parameters within the posterior fossa and 20 analyzed parameters of the craniovertebral junction. The most commonly measured parameters included clivus length (n?=?30), tonsillar position or descent (n?=?28), McRae line length (n?=?26), and supraocciput length (n?=?26). While certain structural anomalies including reduced clivus length have been implicated in CM-I, there is a lack of consensus on how several other morphometric parameters may or may not contribute to its development. Heterogeneity in presentation with respect to the extent of tonsillar descent suggests alternate methods utilizing morphometric measurements that may help to identify CM-I patients and may benefit future research to better understand underlying pathophysiology and sequelae such as syringomyelia.

     

Posterior fossa decompression for life-threatening tonsillar herniation in patients with gliomatosis cerebri: report of three cases

OBJECTIVE AND IMPORTANCE: Gliomatosis cerebri (GC) is a rare type of primary brain tumor that diffusely infiltrates more than two lobes of the brain while the normal cerebral architecture is maintained. To the best of our knowledge, the association between an acquired tonsillar herniation and GC has never been reported. In this article, we describe three patients with progressive gliomatosis of the cerebellar hemispheres who subsequently showed signs and symptoms secondary to tonsillar herniation. Early recognition of this potentially life-threatening complication allowed us to recommend prompt surgical intervention. CLINICAL PRESENTATION: One patient with primary, or Type I, GC presented with suboccipital headaches, and two patients with secondary, or Type II, GC presented with the signs and symptoms of progressive myelopathy. Serial imaging studies demonstrated progressive involvement of the cerebellum, descent of the cerebellar tonsils through the foramen magnum, and cervicomedullary spinal cord compression. INTERVENTION: Once the tonsillar herniation was recognized, all three patients underwent posterior fossa decompression, a cervical laminectomy to the lowest level of the tonsillar herniation, and duraplasty. All three patients experienced immediate improvement in their conditions. CONCLUSION: Early recognition of tonsillar herniation, a possibly overlooked cause of death in patients with GC, allows for early surgical intervention as a potentially lifesaving procedure and significant improvement in the patient's condition.