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。     

Chiari畸形Ⅰ型患者小脑扁桃体下疝程度及脊髓空洞形态与后颅窝容积的相关性

目的:分析Chiari畸形Ⅰ型(Chiari malformation typeⅠ,CMⅠ)患者小脑扁桃体下疝程度及脊髓空洞形态与后颅窝线性容积的关系,探讨影响小脑扁桃体下疝程度的后颅窝解剖学因素。方法:2003年6月~2011年6月在我科接受治疗并符合入选标准的CMⅠ患者共59例,男34例,女25例,年龄16~20岁,平均17.9岁,Risser征5级,均有完整MRI资料(包括头枕部及全脊髓矢状面扫描图像);均无颅内占位性病变、颅骨破坏、后颅窝手术史或获得性Chiari畸形。均伴有不同形态的脊髓空洞,55例(93.2%)伴有不同程度的脊柱侧凸畸形。在MRI T1加权像正中矢状位扫描层面上评估患者的小脑扁桃体下疝程度和脊髓空洞类型;测量后颅窝斜坡长度、枕骨大孔前后径、枕骨鳞部长度、后颅窝矢状径、后颅窝高径和斜坡倾斜角。将CMⅠ患者按照小脑扁桃体下疝严重程度分为三度:Ⅰ度,小脑扁桃体下缘超过枕骨大孔水平5mm但没有到达C1后弓上缘;Ⅱ度,小脑扁桃体下缘尾向移位超过C1后弓上缘但未超过C1后弓下缘;Ⅲ度,小脑扁桃体下缘尾向移位超过C1后弓下缘。依据脊髓空洞类型分为膨胀型、念珠型、细长型和局限型四组。比较不同组间后颅窝线性容积的差异,并对相关指标进行相关性分析。结果:Ⅰ度扁桃体下疝CMⅠ患者的后颅窝斜坡长度明显大于Ⅱ、Ⅲ度扁桃体下疝CMⅠ患者(P<0.05),Ⅲ度扁桃体下疝患者的斜坡倾斜角较Ⅰ、Ⅱ度患者明显减小(P<0.05),其余指标三组间无显著性差异;CMⅠ患者的斜坡倾斜角与小脑扁桃体下疝程度之间存在显著性负相关关系(r=-0.626,P=0.005)。膨胀型脊髓空洞患者的斜坡倾斜角显著小于其他类型的脊髓空洞患者(P<0.05),其余指标各类型之间无显著性差异。结论:后颅窝斜坡短平可能是促使CMⅠ患者小脑扁桃体下疝加重的重要因素之一,同时对CMⅠ患者的脊髓空洞的形成和发展也存在影响。     

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.     

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.     

Clinical and radiological outcome of craniocervical osteo-dural decompression for Chiari I-associated syringomyelia

The aim of this study was to analyze the long-term clinical and radiological outcomes of craniocervical decompression for patients affected by Chiari I-related syringomyelia. We performed a retrospective analysis of a group of patients affected by Chiari I-associated syringomyelia treated by craniocervical decompression (CCD). Surgical and technical aspects and preoperative factors predicting outcome were discussed. A total of 36 patients were reviewed. There were 17 men and 19 women (female/male ratio 1.11), and the mean age was 40.4 (range 18–68). The most important preoperative symptoms were related to myelopathy (pain, weakness, atrophy, spasticity, sensory loss, and dysesthesias). Most syrinxes were in the cervico-thoracic region (61.1%), and the majority of patients had tonsillar descent between the foramen magnum and C1. All patients underwent a craniectomy less than 3 cm in diameter followed by a duroplasty with dura substitute. No arachnoid manipulation was necessary. Three patients (8.1%) experienced cerebrospinal fluid leaks that resolved without complications. At a mean follow up of 40 months (range 16–72) 80.5% of patients exhibited improvement over their preoperative neurological examination while 11.1% stabilized. The syrinx shrank in 80.5% of patients. Chi-square test showed that preoperative syrinx extension and degree of tonsillar descent did not correlate with clinical and neuroradiological postoperative evolution. Treating syringomyelia associated in Chiari I malformation with CCD leads to a large percentage of patients with satisfying results and no irreversible complications.     

Chiari I malformation associated with syringomyelia: can foramen magnum decompression lead to restore cervical alignment?

Purpose

There are few researches that demonstrate the relationship between the extent of syringomyelia and sagittal alignment of the cervical spine. The purpose of this study is to investigate the correlation between the change of syrinx size and cervical alignment.

Methods

From January 2001 to June 2008, we operated on 207 patients who had syringomyelia. The associated diseases were categorized by Chiari I malformation, tumor, trauma, spinal stenotic lesion, inflammatory disease and idiopathic causes. Thirty patients who had Chiari I malformation associated with syringomyelia and who underwent foramen magnum decompression (FMD), participated in this study. We excluded patients with scoliosis, cervical instrumentation, tumor, trauma, myelomeningocele, hydrocephalus, tethered cord and congenital vertebral anomalies. Lateral radiographs in neutral and magnetic resonance imaging were taken pre- and postoperatively.

Results

Mean follow-up was 6.5 ± 1.5 years (ranged from 4.0 to 9.5 years). The mean pre- and postoperative lordosis angles at C2–C7 were −5.9° ± 1.0° and −10.4° ± 1.0°, respectively (P = 0.001). There was significant correlation between the differences of syrinx width and the cervical lordotic angles before and after surgery (P = 0.016). After FMD, syringomyelia and cervical alignment improved in 28 (93.3 %) and 25 (85.18 %) of 30 patients, respectively. There was significant correlation between recovery rate by Japanese Orthopaedic Association scores and the difference of the cervical lordotic angles before and after surgery (P = 0.022).

Conclusions

The present results demonstrate that the decrease of syrinx size by FMD may restore the cervical lordosis. We suggest that the postoperative cervical alignment might be a predictive factor for neurological outcome.     

Cervical alignment and range of motion after laminoplasty: radiographical data from more than 500 cases with cervical spondylotic myelopathy and a review of the literature

STUDY DESIGN.: A large-scale analysis of radiographical results of patients with cervical spondylotic myelopathy and a review of the literature. OBJECTIVE.: To identify changes in sagittal alignment and range of motion (ROM) after cervical laminoplasty. SUMMARY OF BACKGROUND DATA.: Cervical laminoplasty is an effective procedure for decompressing multilevel spinal cord compression. It often induces postoperative complications such as loss of lordotic alignment and restriction of neck motion. Although numerous studies have reported the loss of flexion-extension ROM after laminoplasty, no large-scale study has been reported. METHODS.: Five hundred twenty consecutive patients with cervical spondylotic myelopathy (331 male and 189 female; mean age, 62.2 yr) who underwent modified double-door laminoplasty were enrolled. The average follow-up period was 33.3 months. All patients were allowed to sit up and walk on the first postoperative day using an orthosis, which could be removed within the first 2 weeks, even if long. Early cervical ROM exercises were performed as a part of the rehabilitation schedule. Radiography was performed before surgery and at the final follow-up. Cervical alignment in the neutral and flexion-extension view were measured by the Cobb method at C2-C7. The ROM was assessed by measuring the difference in alignment between flexion and extension. RESULTS.: The mean C2-C7 alignment in the neutral position was 11.9° lordotic preoperatively and 13.6° lordotic postoperatively; the alignment increased by 1.8° in lordosis. The mean total ROM decreased from a preoperative value of 40.1° to 33.5° at the final follow-up, showing a significant difference of 6.6°. The mean total ROM preservation after laminoplasty was 87.9%. CONCLUSION.: Sagittal alignment was slightly changed, with only a 1.8° increase in lordosis. The ROM of the cervical spine was preserved by 87.9%. This preservation of alignment and ROM might be attributable to improvements including early removal of the cervical orthosis, postoperative neck exercises, and some surgical modifications.     

Kinematics after cervical laminoplasty: risk factors for cervical kyphotic deformity after laminoplasty

BACKGROUND CONTEXTLaminoplasty of the cervical spine is widely used as an effective surgical method to treat compressive myelopathy of the cervical spine; however, there is an adverse effect of kyphosis after surgery. The risk factors or predictors of kyphosis have not been sufficiently evaluated.PURPOSETo assess the risk factors for kyphosis following laminoplasty.STUDY DESIGNRetrospective study.PATIENT SAMPLEPatients diagnosed with cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL) who underwent laminoplasty between May 2011 and October 2018 were enrolled.OUTCOME MEASURESChanges in lordosis and range of motion (ROM).METHODSRadiological imaging data were collected from simple neutral and flexion-extension radiographs at baseline and at 2-year follow-up. The ROM from the neutral position to complete flexion was defined as the flexion capacity, and the ROM from the neutral position to complete extension was defined as the extension capacity.RESULTSThis study included 53 patients (mean age, 59.3 years). Multivariate linear regression analysis revealed that, the smaller the preoperative extension capacity, the greater was the decrease in lordosis (p=.025), while the larger the T1 slope, the greater was the decrease in lordosis following laminoplasty (p= .008). Correlation analysis revealed that C2-7 lordosis increased with increasing baseline T1 slope before surgery (p< .01). In patients with large preoperative C2-7 lordosis, the postoperative decrease in ROM tended to be greater (p= .028). However, the degree of lordosis and ROM reduction did not demonstrate a clear correlation with the clinical outcomes at 2 years after surgery.CONCLUSIONSKyphotic changes in the cervical spine following laminoplasty were related to preoperative radiological parameters. The greater the preoperative extension capacity, the lower was the decrease in lordosis, and the greater the T1 slope, the greater was the decrease in lordosis.     

Symptomatic Chiari malformation in adults: a new classification based on magnetic resonance imaging with clinical and prognostic significance

Thirty-five consecutive adults with Chiari malformation and progressive symptoms underwent surgical treatment at a single institution over a 3-year period. All patients underwent magnetic resonance imaging scan before and after surgery. Images of the craniovertebral junction confirmed tonsillar herniation in all cases and allowed the definition of two anatomically distinct categories of the Chiari malformation in this age group. Twenty of the 35 patients had concomitant syringomyelia and were classified as Type A. The remaining 15 patients had evidence of frank herniation of the brain stem below the foramen magnum without evidence of syringomyelia and were labeled Type B. Type A patients had a predominant central cord symptomatology; Type B patients exhibited signs and symptoms of brain stem or cerebellar compression. The principal surgical procedure consisted of decompression of the foramen magnum, opening of the fourth ventricular outlet, and plugging of the obex. Significant improvement in preoperative symptoms and signs was observed in 9 of the 20 patients (45%) with syringomyelia (Type A), as compared to 13 of the 15 patients (87%) without syringomyelia (Type B). Postoperative reduction in syrinx volume was observed in 11 of the 20 patients with syringomyelia, including all 9 patients with excellent results. Magnetic resonance imaging has allowed a classification of the adult Chiari malformation in adults based on objective anatomic criteria, with clinical and prognostic relevance. The presence of syringomyelia implies a less favorable response to surgical intervention.     

Resolution of tonsillar herniation and syringomyelia after supratentorial tumor resection: case report and review of the literature

OBJECTIVE AND IMPORTANCE: The pathophysiological features of syringomyelia are not yet entirely understood. We present a case of a supratentorial mass causing tonsillar herniation and syringomyelia. CLINICAL PRESENTATION: A 51-year-old woman underwent magnetic resonance imaging for evaluation of progressive headaches. A large parieto-occipital mass was revealed. Herniation of the cerebellar tonsils and a cervical syrinx were also noted. INTERVENTION: A craniotomy was performed without incident. After tumor resection, the tonsils ascended and the syrinx resolved in a 1-year period. CONCLUSION: This case highlights the importance of tonsillar herniation in the pathogenesis of syringomyelia. "Acquired" Chiari malformations and syringomyelia attributable to supratentorial masses may be treated by mass resection alone, without the need for foramen magnum decompression.     

Chiari malformation (type I) associated with bilateral abducens nerve palsy: case report

There are still many questions concerning the pathology and therapeutic strategy for Chiari malformation. We recently encountered a case of Chiari malformation associated with only bilateral abducens nerve palsy which was successfully treated by foramen magnum decompression. The pathology and mechanisms of Chiari malformation (type I) were evaluated in this case. The patient was a 12-year-old girl who had visited our institute 1 month previously complaining of diplopia. She had no particular past or family history and her general appearance was also normal. Bilateral abducens nerve palsy was the only neurological deficit. Her cerebrospinal pressure was 9 cm H2O. Neuroradiological findings revealed basilar impression, C4-6 syringomyelia and Chiari malformation (type I), but no hydrocephalus or meningocele. Foramen magnum decompression with lateral extension, upper cervical laminectomy and open duraplasty were performed. The position of both eyes recovered fully shortly after surgery, and diplopia occurred only when the patient looked sideways. Eye movements also returned completely to normal 3 months after surgery. MRI showed no syringomyelia 4 months after surgery, the upward shift of the pendulous portion of the cerebellar tonsil, and the expansion of the subarachnoidal space of the pons-oblongata junction. In conclusion, it was thought that the mechanism of bilateral abducens nerve palsy in this case was due to the strangulation and the downward traction of the pons-oblongata junction. The nerve was relieved from this traction by foramen magnum decompression.     

Surgical outcomes of foramen magnum decompression for syringomyelia associated with Chiari I malformation: relation between the location of the syrinx and body pain

Background  

There have been few reports about the relation between the morphology of syrinxes and body pain in syringomyelia associated with Chiari I malformation. To investigate this phenomenon, the relation between the location of the syrinx and body pain before and after foramen magnum decompression (FMD) were evaluated.     

Initial management of hydrocephalus associated with Chiari malformation Type I-syringomyelia complex via endoscopic third ventriculostomy: an outcome analysis

OBJECT: The aim of this study was to evaluate the efficacy of endoscopic third ventriculostomy (ETV) in patients with Chiari malformation Type I (CM-I) and hydrocephalus with or without syringomyelia. METHODS: The authors identified, in a prospective endoscopy database, 16 adults and children (age range 2-68 years) with CM-I and hydrocephalus that had been managed with ETV. They reviewed the clinical features and radiographic findings for all patients. Fifteen patients underwent ETV as a primary treatment, whereas 1 patient underwent the procedure at the time of shunt failure. All patients had symptomatic hydrocephalus with either aqueductal or fourth ventricular outflow obstruction. The mean duration of follow-up was 42 months. RESULTS: Fifteen patients (94%) remain shunt free following ETV for CM-I. Five (83%) of the 6 patients with a syrinx had improvement or resolution of the syrinx following ETV. Six patients (37.5%) underwent foramen magnum decompression for persistent CM-I -- or syrinx-related symptoms. There was no cerebrospinal fluid leakage or intracranial pressure-related problem following foramen magnum decompression. CONCLUSIONS: Endoscopic third ventriculostomy provides a durable method of treatment for hydrocephalus associated with CM-I. It is effective as a primary treatment, and the authors advocate its use as a replacement for routine ventriculoperitoneal shunt insertion in these patients. Management of the hydrocephalus alone is often sufficient and may obviate decompression, although a significant proportion of patients will still need both procedures.     

Syringomyelia Associated with Type I Chiari Malformation A 21-Year Retrospective Study on 75 Cases Treated by Foramen Magnum Decompression with a Special Emphasis on the Value of Tonsils Resection

Summary  The purpose of the present study is to evaluate retrospectively the effects of several intra-operative manipulations on the results of foramen magnum decompression (FMD) in patients having syringomyelia associated with type I Chiari malformation. Seventy-five patients having syringomyelia associated with Chiari I malformation were operated on between 1975 and 1996. This population was grouped into 4 subgroups according to the surgical protocol: group I=42 patients with FMD alone; group II=16 patients with FMD and third ventricle shunting; group III=9 patients with FMD and syringosubarachnoid shunting (SSS); group IV=8 patients with FMD and cerebellar tonsils resection. Pre- and postsurgical magnetic resonance imaging (MRI) studies were analyzed (and compared). Nine patients were lost to follow-up. The results were evaluated in the 66 remaining patients (mean follow-up: 52 months), using the Bidzinski's outcome scale (ref). Two patients (3%) died postoperatively, 31 (47%) had very good results (after additional surgery in 7), 16 (24,2%) had good results (after additional surgery in 7) and 17 (25,7%) had poor results despite further surgery in 9. A total of 27 reoperations were undertaken after primary FMD in 23 patients (35%). Thirty-nine patients (59%) had both pre- and postsurgical MRI evaluation. In 28 (72%) the syrinx had markedly decreased whereas it had remained stable in 11 (28%). Clinical results were not significantly different between the patients of groups I, II and III. Very good or good results were obtained in 24 patients (64,8%) of group I (after additional surgery in 10), in 8 (61,5%) of group II (after additional surgery in 1) and in 7 (87,5%) of group III (after additional surgery in 3). Results in group IV were as follows: 7 patients (87%) had very good results and one had a good result. With a mean follow-up of 28 months, no patient required additional surgery. Postsurgical MRI syrinx reduction was observed in all 8 patients either in the early postoperative course or on delayed follow-up. It is suggested that tonsils resection might enhance the results of FMD in individuals having Chiari I-related syringomyelia.     

The effect of lumbar total disc replacement on the spinopelvic alignment and range of motion of the lumbar spine

A lumbar total disc replacement (TDR) is a type of motion-preserving surgery, which aims to restore and maintain the normal range of motion (ROM) and the sagittal balance of the spine. However, little is known regarding how the spinopelvic alignment and ROM of the lumbar spine are influenced by the lumbar TDR with ProDisc. This study retrospectively analyzed the sagittal alignment and ROM of the lumbar spine in 26 consecutive patients who had undergone the TDR with ProDisc with a minimum follow-up of 24 months. A standing lateral radiograph, which included the femoral heads and dynamic flexion-extension lateral radiographs of the spine were taken before surgery and at the follow-up visit. The radiological parameters included the sacral tilt, the pelvic tilt, and the lumbar lordosis. The segmental lordosis and ROM were also measured at each operative level. Nineteen patients underwent a single-level TDR and 7 patients underwent a double-level TDR. The mean lumbar lordosis increased significantly from 30.5 degrees to 40.8 degrees in all patients who underwent TDR without any significant changes in the sacral tilt and pelvic tilt at the latest follow-up (P<0.05). In the patients who underwent single-level TDR, the mean segmental lordosis at the L5-S1 and L4-5 operative levels increased significantly from 15.8 degrees to 23.2 degrees and from 14.1 degrees to 24.9 degrees, respectively. The mean ROM at L5-S1 and L4-5 increased significantly from 7.1 degrees to 11.2 degrees and from 11.4 degrees to 14.6 degrees, respectively. The sagittal balance and ROM of the lumbar spine improved significantly after the lumbar TDR.     

Hiccups attributable to syringobulbia and/or syringomyelia associated with a Chiari I malformation: case report

OBJECTIVE AND IMPORTANCE: Approximately 20 to 50% of patients with syringomyelia associated with Chiari malformations exhibit cranial nerve or cerebellar symptoms. However, hiccups represent a rare clinical manifestation of this disorder. We report a case of intractable hiccups resulting from syringobulbia associated with a Chiari I malformation, which was successfully treated with foramen magnum decompression. CLINICAL PRESENTATION: We report the case of a patient who presented with syringomyelia and syringobulbia associated with a Chiari I malformation, manifested as intractable hiccups and neurological deficits. Magnetic resonance imaging scans demonstrated syringobulbia in the dorsal medullary region and a large cervical syrinx from C2 to C6-C7, associated with a Chiari I malformation. INTERVENTION: Foramen magnum decompression and a C1 laminectomy were performed. One month later, the intractable hiccups disappeared and the neurological symptoms demonstrated improvement. CONCLUSION: Postoperative magnetic resonance imaging scans demonstrated enlargement of the subarachnoid space in the posterior fossa and disappearance of the syringobulbia. There has been no recurrence of intractable hiccups and syringobulbia in 6 months after surgery. Magnetic resonance imaging of the brainstem is an important diagnostic procedure for intractable hiccups, because syringobulbia associated with a Chiari malformation represents a surgically treatable disorder, although the incidence is low.     

Retrocerebellar arachnoid cyst resulting in syringomyelia in a patient without tonsillar herniation: successful surgical treatment with reconstruction of CSF flow in the foramen magnum region

A retrocerebellar arachnoid cyst causing syringomyelia is extremely rare without tonsillar herniation. The authors present a 44-year-old woman with symptoms of foramen magnum compression and syringomyelia. Magnetic resonance imaging demonstrated a large retrocerebellar arachnoid cyst with a large cervicothoracic syrinx but no signs of tonsillar herniation or hydrocephalus. The patient underwent a foramen magnum decompression with C1 laminectomy, microsurgical fenestration of the cyst, and duraplasty. After successful reconstruction of CSF flow, the patient experienced a relief of symptoms and a significant reduction of the syrinx. The intraoperative findings support the theory of a piston mechanism in the development of syringomyelia. Additional arachnoidal adhesions may also obstruct the CSF flow around the craniocervical junction. We recommend the surgical treatment should consist of an adequate decompression of the foramen magnum, wide microsurgical arachnoidal debridement, and duraplasty with autologous grafts sutured in a watertight way.     

Reversible tonsillar prolapse and syringomyelia after embolization of a tectal arteriovenous malformation. Case report and review of the literature

The authors report the case of a 21-year-old woman who presented with headaches, frequent sensations of loss of equilibrium, and intermittent strabismus. A tectal arteriovenous malformation (AVM) was diagnosed based on magnetic resonance (MR) imaging findings. The AVM drained toward the straight sinus and was associated with a tonsillar prolapse (Chiari malformation Type I [CM-I]) and cervical syringomyelia. The tectal AVM was embolized with N-butyl cyanoacrylate, and disconnection of about 80% of the lesion was obtained. All clinical symptoms resolved after embolization, and radiosurgery was proposed to treat the malformation remnant. A control MR image confirmed the regression of the tonsillar prolapse and the disappearance of the syrinx. This report emphasizes that CM-I and syringomyelia may be acquired and related to hydrovenous disorders.     

Circumferential decompression of the foramen magnum for the treatment of syringomyelia associated with basilar invagination

Posterior fossa decompression utilizing suboccipital craniectomy and duraplasty remains the standard surgical treatment for Chiari-associated syringomyelia. In the presence of basilar invagination, anterior decompression, typically transoral odontoidectomy, or posterior decompression may be performed. We report two cases in which anterior and posterior (circumferential) decompression of the foramen magnum was used to treat cervical syringomyelia successfully. These cases demonstrate that circumferential decompression of the foramen magnum may be necessary in some cases of cervical syringomyelia associated with basilar invagination and Chiari malformation.