C1–C2 arthrodesis after transoral odontoidectomy and suboccipital craniectomy for ventral brain stem compression in Chiari I patients

Chiari I malformations are often associated with congenital craniocervical anomalies such as platybasia, basilar invagination, and retroflexion of the odontoid process. Management of ventral brain stem compression associated with Chiari I malformations remains controversial, but several authors report a significant rate of failure with suboccipital decompression alone in the presence of pronounced ventral brain stem compression (VBSC). Treatment options described in the literature for these patients involve anterior, posterior, or combined decompressions with or without concurrent arthrodesis. A combined anterior and posterior approach provides a definitive circumferential decompression but also significantly disrupts the stability of the occipitocervical junction usually necessitating occipitocervical fixation. We describe an alternative surgical treatment for Chiari I patients with significant ventral brain stem compression where a combined anterior and posterior decompression was considered necessary. We report two patients who underwent transoral odontoidectomy with preservation of the anterior arch of the atlas and suboccipital craniectomy with C1 laminectomy followed by C1–C2 arthrodesis. Preservation of the anterior arch of the atlas in conjunction with C1–C2 arthrodesis stabilizes the occipito–atlanto-axial segments while conserving more cervical mobility as compared to an occipitocervical fusion.     

Chiari I malformation associated with atlanto-axial dislocation: focussing on the anterior cervico-medullary compression

Summary Background. Chiari I malformation with atlantoaxial dislocation may cause both posterior and anterior cervicomedullary compression. We studied the clinicoradiological features and surgical outcome in patients having Chiari I malformation with atlantoaxial dislocation. Method. Thirty-nine patients with Chiari I malformation with atlanto-axial dislocation underwent preoperative and follow-up neurological status assessment. In Chiari I malformation with reducible atlanto-axial dislocation (n = 11), a direct posterior stabilization was done. In Chiari I malformation with irreducible atlanto-axial dislocation (n = 28), a single stage transoral decompression with posterior stabilization and/or posterior decompression and duraplasty were done in 18 patients. In 10 patients, only posterior decompression and/or posterior stabilization was performed. Seven among the latter patients subsequently deteriorated and required transoral decompression. Comparison of mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization versus the posterior procedure alone was done using T-test and proportional significance also calculated. Findings. Patients with Chiari I malformation with atlanto-axial dislocation have a high incidence of long tract signs and sphincteric disturbances with a decrease in the mean foramen magnum diameter. The mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization were significantly better than those patients who underwent the posterior procedure alone. The latter patients also showed significant clinical improvement following transoral decompression. In the presence of Chiari I malformation with reducible atlanto-axial dislocation, reduction and stabilization of atlanto-axial dislocation resulted in neurological improvement. The follow up neurological status scores of these patients improved after surgical intervention even in the presence of poor preoperative grades. Conclusions. Patients with Chiari I malformation should be investigated for the presence of atlanto-axial dislocation. In case atlantoaxial dislocation coexists, priority must be given to relieving anterior cervicomedullary compression.     

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.     

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.     

经后路椎管前方减压治疗陈旧性胸腰椎骨折截瘫

目的：探讨陈旧性胸腰椎骨折截瘫后路椎管前方减压治疗的有效性。方法：59例陈旧性胸腰椎骨折瘫病人,平均伤后22个月,42例曾行椎板切除,经后正中入路,经一侧椎弓板内侧至椎体后缘行椎管前方减压,平均随诊14个月（1－8年）,结果：截瘫恢复率72．9％（43／59）,不全截瘫中术后Frankel分级提高一级或一级以上为84．4％（38／45）;排便功能改善率47％（28／59）,椎管扩大率48％,结论：脊髓前方有压迫的不全截瘫,尤其已行后路手术,留有内固定者,更适用于经后路椎管前方减压,为最大限度减压,椎管一侧压迫为主者,可行单侧椎弓根内侧减压,如椎管前方两侧压迫均重,就行双侧经椎弓根侧减压术。此方法效果满意,创伤小,出血少。     

Combined anterior and posterior approach for managing basilar invagination associated with type I Chiari malformation

Ventral brainstem compression is common in patients with basilar invagination associated with type I Chiari malformation. The aim of this study was to investigate the reliability of a combined one-session anterior-posterior surgical approach for these patients. Nine patients underwent transoral odontoidectomy, posterior foramen magnum decompression, occipitocervical fixation, and bone grafting. All but two patients had ventral and dorsal operations in one surgical sitting. One of these two individuals had previously undergone posterior decompressive surgery at another hospital, but his condition had deteriorated rapidly afterward. The mean follow-up time was 19 months (range, 14-30 months). There was no mortality and no significant morbidity in this series. All but one of the patients showed significant improvement in their symptoms. Chiari malformations have a surprisingly high association with basilar invagination, and patients may have symptoms in both conditions. If there is a marked anterior compression, anterior transoral and posterior decompression, fusion, and instrumentation is an optimal strategy for treating patients with basilar invagination associated with type I Chiari malformation.     

Hydrosyringomyelia and its management in childhood

Syringomyelia, once regarded as a degenerative disease of adults, is now recognized to be a disorder usually associated with the Chiari malformation and occurring in patients of all ages. We have reviewed 47 patients with syringomyelia treated on the Neurosurgical Service at the Hospital for Sick Children during the years 1977 to 1985. Twelve of these patients had a Chiari I malformation, 30 had a Chiari II malformation, and 5 had an acquired Chiari malformation. Thirty-one of these patients were treated by decompression of the Chiari malformation and plugging of the obex, 5 were treated by a simple posterior fossa decompression, 9 were treated by shunting of the syringomyelic cavity, and 2 were treated by a combined decompression of the posterior fossa and shunting of the syrinx. The Gardner procedure (decompression of the Chiari malformation and plugging of the obex) was the procedure most commonly used in managing our group of patients and resulted in improvement in over 70% of patients.     

Chiari type 1 malformation and magnetic resonance imaging

The Chiari type 1 malformation is common. Unlike the Chiari type 2 and 3 malformations, it may remain latent for a long time, becoming symptomatic only in adulthood. The introduction of MRI has resulted in an increased number of diagnoses of this malformation in pediatric patients. It appears to be related to underdevelopment of the posterior cranial fossa. It must be differentiated from acquired tonsillar herniation, particularly when herniation results from intracranial hypotension; these cases are sometimes reported as acquired Chiari I malformation with spontaneous resolution. Tonsillar ectopia may cause symptoms by its direct effect on any or all of the medulla and the cerebellar and upper spinal cord. The most suggestive of the oculomotor disturbances is oscillopsia with downbeat nystagmus. Dysphonia and dysphagia are common. Potentially serious autonomic disturbances are also frequent: sleep apnea, respiratory failure, syncope and even sudden death. Another risk is syrinx formation, resulting from obstruction of CSF circulation in the cisterna magna. Syringomyelia is detected in 32 to 74% of patients with Chiari I malformation. Treatment is surgical. Posterior fossa decompression is achieved by suboccipital craniectomy combined with laminectomy of the upper cervical segments. Surgical intervention is indicated when the malformation is symptomatic and there is no doubt that it is the cause of the symptoms. When a Chiari I malformation is identified fortuitously on MRI, long-term monitoring is essential. The risk of developing symptoms increases over time. Patients should be advised not to participate in contact sports.     

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.     

Chiari I malformation with underlying pseudotumor cerebri: Poor symptom relief following posterior decompression surgery

Introduction Pseudotumor cerebri (PTC) patients exhibit clear clinical signs and symptoms of higher intracranial pressure (ICP) without ventricular enlargement or mass lesions. The clinical picture of patients with PTC can sometimes be similar to that of Chiari Malformation type I (CMI). There is some evidence that Chiari I malformation and PTC may coexist, which raises the question of whether PTC is an idiopathic disease or a complication of posterior decompression surgery—treatment of choice for Chiari I malformation.Presentation of casesA retrospective review of electronic medical records of patients diagnosed with PTC at the University of Toledo Medical Center (UTMC) was performed. The objective was to determine whether PTC patients had a concurrent diagnosis of Chiari I malformation and whether the diagnosis of PTC occurred before or after posterior decompression surgery. Out of the 8 eligible patient medical records reviewed, 5 patients diagnosed with PTC had undergone posterior decompression surgery for Chiari I malformation at anywhere from several days to three years prior to being diagnosed with PTC. The diagnosis of PTC was based on temporary symptomatic relief following lumbar puncture which also showed elevated CSF opening pressures. Finally, a VP shunt was placed in each of the 5 patients to relieve the elevated intracranial pressure which resulted in the complete resolution of the patients' symptoms.DiscussionOur study focuses on patients who were diagnosed with and treated for CMI then reported back to the clinic within several days to three years complaining of symptoms of headache. Upon re-presenting to the clinic, a CSF flow study was performed which showed normal flow of CSF. Then, these patients underwent a lumbar puncture which demonstrated an elevated opening pressure (and ICP) and a temporary relief of the headache with lumbar drainage. A VP shunt was placed for each patient to treat for PTC, and the patients’ headaches were relieved.ConclusionThis study suggests that the presence of Chiari I malformation in a patient conceals the symptoms of PTC which may become apparent following posterior decompression surgery. Other possibilities could be that the patients are misdiagnosed for Chiari I malformation when they are in fact suffering from PTC, or that PTC is a complication of surgery.     

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.     

Arnold-Chiari 1 malformation type 1 with syringohydromyelia presenting as acute tetraparesis: A case report

Abstract

Context

A 19-year-old woman who presented to a community hospital after awakening with tetraparesis, generalized paresthesia, and severe neck pain, and was transferred to an acute care hospital.

Findings

Magnetic resonance imaging of the head and spine was performed and revealed a cystic lesion extending from the C1 level to the C6 level as well as an Arnold-Chiari type 1 malformation. Emergent surgical posterior fossa decompression with duraplasty and C1 laminectomy was undertaken. Most symptoms improved immediately postoperatively. On post-operative day 15, the patient was transferred to our acute rehabilitation hospital for an additional 16 days. With continued aggressive therapy, she demonstrated complete resolution of tetraparesis as well as significant improvement in muscle strength and function in addition to resolution of paresthesia and neck pain. Functional independence measure scores were 69/126 on admission to 110/126 on discharge from the rehabilitation hospital. Her tetraparesis eventually resolved; manual muscle testing scores on follow-up 2 months later were 5/5 in all four extremities.

Clinical relevance

This is the first reported case of Chiari I malformation with syringohydromyelia presenting as acute tetraparesis, generalized paresthesia, and neck pain. Surgical decompression leading to resolution of symptoms made other etiologies extremely unlikely and there was no history of trauma. The different theories on the pathogenesis of syringomyelia are discussed.     

Rapid development of Chiari I malformation in an infant with Seckel syndrome and craniosynostosis. Case report and review of the literature

To illustrate the rapidity with which a child can develop a severe, symptomatic Chiari I malformation, the authors present the case of a 3-month-old infant with Seckel syndrome (microcephaly, micrognathia, craniosynostosis, and multiple other abnormalities) and posterior sagittal and bilateral lambdoid synostosis. The infant underwent magnetic resonance (MR) imaging shortly after birth; the initial image demonstrated the cerebellar tonsils in the posterior fossa, with no herniation. He subsequently developed severe apneic episodes and bradycardia; repeated MR imaging at 3 months demonstrated severe tonsillar herniation with compression of the brainstem. The child underwent posterior fossa remodeling surgery, including release of the posterior sagittal and lambdoid sutures and decompression of the Chiari I malformation. The patient's apnea gradually improved; however, he died of complications of pneumonia and sepsis several weeks later. The authors identified from the literature 21 patients in whom there was a documented MR image or other neuroimage that did not reveal evidence of a Chiari I malformation, followed by a subsequent study with clear documentation of the presence of Chiari I malformation. The interval between the initial study and the development of the tonsillar herniation ranged from 11 days to 18.5 years. In most cases, a lumbar cerebrospinal fluid (CSF) diversion had been performed. This patient developed a severely symptomatic Chiari I malformation during a 3-month period. These reports illustrate that the Chiari I malformation can develop rapidly in the face of increased intracranial pressure, craniosynostosis, and spinal CSF diversion.     

Spinal cord edema preceding syringomyelia associated with Chiari I malformation--case report

A 38-year-old woman with Chiari I malformation presented with spinal cord edema preceding syringomyelia manifesting as a 5-month history of nuchal pain and numbness of the upper extremities. Magnetic resonance imaging showed spinal cord edema, a poorly defined syrinx at the C-2 to T-2 levels, and distorted cerebellar tonsils. Computed tomography revealed cerebrospinal fluid (CSF) density in the center of spinal cord edema, and positron emission tomography revealed no uptake of L-[methyl-11C]methionine, indicating a non-neoplastic lesion. Craniocervical decompression achieved excellent clinical and neuroradiological outcomes. The success of surgical treatment supports the theory that patients with Chiari I malformation have increased transmural flow of CSF, causing spinal cord edema that progresses to syringomyelia. Early treatment of patients with spinal cord edema is indicated to prevent permanent spinal cord injury due to progressive syringomyelia.     

Chiari malformation with syringocephaly. Case report

A 69-year-old white woman presented with a left hemiparesis which progressed to quadriparesis and encephalopathy. Computerized tomography and magnetic resonance imaging revealed a Chiari I malformation and a hydromyelic cavity extending from C-2 to T-6. Rostrally, the cavity extended through the ventral medulla, pons, and right cerebral peduncle into the right cerebral hemisphere, where the cavity enlarged and was associated with mass effect. The patient has made a dramatic neurological recovery following suboccipital craniectomy with insertion of a dural graft to decompress the Chiari malformation and upper cervical laminectomy and dorsal root entry zone myelotomy to decompress the hydromyelia.     

Hemifacial spasm in a patient with Marfan syndrome and Chiari I malformation. Case report

Marfan syndrome, hemifacial spasm, and Chiari malformation are all relatively rare and seemingly separate entities. Marfan syndrome is caused by a defect in the gene that encodes fibrillin and leads to weakness of the artery wall. Hemifacial spasm results from compression of the facial nerve by an abnormal artery. Chiari malformation is characterized by a small posterior fossa. The authors report the case of a patient with Marfan syndrome who presented with hemifacial spasm and was also found to have a Chiari malformation Type I. The patient's Chiari malformation and hemifacial spasm were successfully treated by performing suboccipital and microvascular decompression surgeries, respectively. The pathophysiological characteristics of Marfan syndrome, hemifacial spasm, and Chiari malformation are discussed, and the authors propose a link between these conditions in this patient. The authors hypothesize that the patient's Marfan syndrome contributed to the abnormal shape of his vertebral artery and that, given the lack of space in his crowded posterior fossa due to the Chiari malformation, the artery caused compression of his facial nerve, resulting in hemifacial spasm.     

Foramen magnum decompression for the treatment of Arnold Chiari malformation type I with associated syringomyelia in an elderly patient

STUDY DESIGN: Report of a rare case of an elderly patient with late onset of Arnold Chiari malformation type I with associated syringomyelia that was successfully treated with foramen magnum decompression. OBJECTIVE: To report this rare case along with a literature review. SETTING: Gifu, Japan. METHODS: A 69-year-old woman with a 4-year history of dull pain in her right arm was referred to the clinic. After physical and radiographical examinations, she was diagnosed with Arnold Chiari malformation type I with associated syringomyelia. A foramen magnum decompression by the removal of the outer layer of the dura mater was performed. RESULTS: At 2 years postoperatively, MRI revealed a decrease in the size of the syringomyelia. Her symptoms had also remarkably improved. CONCLUSIONS: A rare case of symptomatic Arnold Chiari malformation type I with associated syringomyelia in an elderly woman was successfully treated with foramen magnum decompression by the removal of the outer layer of the dura mater.     

Hidden aqueductal stenosis associated to bilateral idiopathic foramina of Monro stenosis mimicking a Chiari I malformation? Case report

A 39-year old man came to our outpatient clinic with long history of unspecific symptoms and signs. Cerebral MRI showed herniation of the cerebellar tonsils of more than 1?cm below the foramen magnum and a triventricular hydrocephalus. A diagnosis of Chiari I malformation was retained. After an osteo-dural decompression of the posterior fossa, post-operative MRI revealed an aqueductal stenosis with triventricular hydrocephalus. An endoscopic-third- ventriculostomy showed an idiopathic stenosis of the right foramen of Monro. Residual symptoms and persistence of biventricular hydrocephalus justified a ventriculo-peritoneal shunt. Aqueductal and foramina of Monro stenosis can mimick a Chiari I malformation.     

Malformations of the craniocervical junction (chiari type I and syringomyelia: classification,diagnosis and treatment)

Chiari disease (or malformation) is in general a congenital condition characterized by an anatomic defect of the base of the skull, in which the cerebellum and brain stem herniate through the foramen magnum into the cervical spinal canal. The onset of Chiari syndrome symptoms usually occurs in the second or third decade (age 25 to 45 years). Symptoms may vary between periods of exacerbation and remission. The diagnosis of Chiari type I malformation in patients with or without symptoms is established with neuroimaging techniques. The most effective therapy for patients with Chiari type I malformation/syringomyelia is surgical decompression of the foramen magnum, however there are non-surgical therapy to relieve neurophatic pain: either pharmacological and non-pharmacological. Pharmacological therapy use drugs that act on different components of pain. Non-pharmacological therapies are primarly based on spinal or peripheral electrical stimulation.     

Chiari Type I malformation presenting as glossopharyngeal neuralgia: case report

OBJECTIVE AND IMPORTANCE: Chiari Type I malformation is an important pathological state in which the brainstem is compressed by the cerebellar tonsil. We present a case of glossopharyngeal neuralgia caused by Chiari Type I malformation. CLINICAL PRESENTATION: A 50-year-old male patient was admitted with glossopharyngeal neuralgia. Magnetic resonance imaging studies revealed caudal displacement of the left cerebellar tonsil. INTERVENTION: Small occipital craniectomy and C1 laminectomy were performed. The left cerebellar tonsil was resected. CONCLUSION: This glossopharyngeal neuralgia was caused by compression of the lower cranial nerves and brainstem by the displaced left cerebellar tonsil. Decompression and pain relief were obtained with resection of the cerebellar tonsil. The patient was pain-free 30 weeks after the operation.