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.     

Transoral decompression evaluated by cine-mode magnetic resonance imaging: a case of basilar impression accompanied by Chiari malformation

Cine-mode magnetic resonance imaging provides simultaneous images of cerebrospinal fluid flow dynamics. A patient with a basilar impression accompanied by a Chiari malformation and von Recklinghausen's disease who underwent transoral decompression is reported. Preoperative cine-mode magnetic resonance imaging visualized an associated obstruction of cerebrospinal fluid pulsatile flow at the level of the foramen magnum. Tonsilar herniation (Chiari I malformation) and hydrocephalus were also present. Postoperatively, the obstruction of cerebrospinal fluid flow was resolved concomitant with the correction of the cervicomedullary angulation. On the basis of observations made by magnetic resonance imaging, the surgical treatment of basilar impression accompanied by Chiari malformation is briefly discussed.     

Transmaxillary anterior decompressions in patients with severe basilar impression

Severe basilar impression leads to an upward translocation of the upper cervical spine and clivus into the foramen magnum and is a diagnosis best made with computed tomography or magnetic resonance imaging scans. Basilar impression may be a primary condition or secondary to bone softening disorders. Symptoms relating to direct neuraxial compression, obstruction to cerebral spinal fluid outflow, and vascular compromise all have been described. Management depends on the exact nature of the abnormality seen, but it is now firmly accepted that those with anterior neuraxial compression should have an anterior decompression. The severe basilar impression and craniofacial abnormalities seen in osteogenesis imperfecta together with the progressive nature of the condition have led to the development of a specific surgical response, the open door maxillotomy combined with a contoured loop fixation of the cervical spine. Little is known of the long term outcome of severe basilar impression, and long term studies undertaken by centers familiar with the condition and its management are required if definitive care is to be delivered to these patients.     

Trigeminal Neuralgia Associated with Achondroplasia. Case Report with Literature Review

Summary  A 59-year-old male with a history of 2 years of typical trigeminal neuralgia manifested the characteristics of achondroplasia. X-ray and magnetic resonance imaging demonstrated basilar impression, deformity of the posterior fossa with marked asymmetry of petrous bone and compression of pons and trigeminal nerve by the left vertebral artery and anterior inferior cerebellar artery. Microvascular decompression was performed through a suboccipital craniectomy. The neuralgia disappeared soon after surgery and remains completely resolved until today. This is the first reported case of trigeminal neuralgia in a patient with achondroplasia. The deformity of the skull base was considered to influence the development of the trigeminal neuralgia.     

Arteriovenous malformation at the cervicomedullary junction: A case report with magnetic resonance imaging

A rare case of arteriovenous malformation at the cervicomedullary junction is reported. A 72-year-old man developed symptoms of total transection of the upper cervical cord without evidence of subarachnoid hemorrhage. The arteriovenous malformation had an intramedullary nidus with an aneurysmal dilatation at the C-1 level. This lesion was diagnosed by magnetic resonance imaging and confirmed at autopsy. The neurological symptoms may have been due to compression of the spinal cord by the intramedullary lesion, followed by degeneration and necrosis. The usefulness of magnetic resonance imaging in the neuroradiological diagnosis is particularly emphasized.     

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.     

Magnetic resonance imaging of vertebrobasilar ectasia in tic convulsif. Case report

A patient with trigeminal neuralgia and hemifacial spasm was evaluated using multiplanar magnetic resonance (MR) imaging with gadolinium enhancement. Preoperative images demonstrated massively ectatic vertebral and basilar arteries and their distortion of the brain stem and the trigeminal and facial nerves. Surgical manipulation included selective trigeminal rhizotomy, cushioning of the residual nerve at the point of maximal distortion by the underlying basilar artery, and microvascular decompression of the seventh nerve from the anterior inferior cerebellar artery which was being pushed dorsomedially by the vertebral artery. Postoperatively, the patient had neither trigeminal neuralgia nor facial spasm. Gadolinium-enhanced MR imaging not only excludes other etiologies such as tumor or arteriovenous malformation, but also demonstrates cranial nerve compression by ectatic vertebral and basilar arteries. The choice of preoperative imaging modality is discussed and the literature concerning the etiology of tic convulsif is reviewed.     

Transoral-transpharyngeal approach to the anterior craniocervical junction. Ten-year experience with 72 patients

The anterior transoral-transpharyngeal operation to correct ventral irreducible compression of the cervicomedullary junction was utilized in 72 individuals. The patients' ages ranged from 6 to 82 years, and 29 were children. The pathology encountered was primary basilar invagination, rheumatoid irreducible cranial settling, secondary basilar invagination due to migration of odontoid fracture fragments, dystopic os odontoideum, granulation masses, clivus chordoma, osteoblastoma, and chondroma of the atlas. Fifteen patients had associated Chiari malformation with basilar invagination. Fifty-two patients required subsequent atlantoaxial or occipitocervical fusion. Neurological improvement was the rule. There were two deaths within 30 days of surgery: one from myocardial infarction 4 weeks after surgery and one from Gram-negative septicemia of urinary tract origin. There was one pharyngeal wound infection. The ventral transoral approach provides a safe, rapid, and effective means for decompression of the abnormal craniovertebral junction.     

Spontaneous resolution of syringomyelia: report of two cases and review of the literature

OBJECTIVE AND IMPORTANCE: The natural history of syringomyelia is highly unpredictable, and some patients experience improvement or stabilization without surgery. However, the mechanisms of the formation and spontaneous resolution of syringomyelia remain controversial. This report concerns two patients with syringomyelia who demonstrated spontaneous reductions in syrinx size, accompanied by symptomatic improvement. CLINICAL PRESENTATION: One patient was a 10-year-old girl with syringomyelia associated with a tight cisterna magna and basilar impression, who demonstrated a spontaneous decrease in syrinx size, accompanied by symptomatic improvement, in 22 months. The other patient was a 39-year-old man with syringomyelia associated with a Chiari I malformation, who demonstrated a spontaneous reduction in syrinx size and neurological improvement, accompanied by elevation of the cerebellar tonsils, 6 months after diagnosis. INTERVENTION: The patients were monitored. CONCLUSION: The mechanisms of spontaneous resolution of syringomyelia, as well as the factors leading to the cerebrospinal fluid flow disturbances that cause syringomyelia, may vary. Resolution of foramen magnum lesion-related syringomyelia may be the result of spontaneous correction of the abnormal cerebrospinal fluid flow, as observed in our cases, or of cavity fluid drainage into the spinal arachnoid space because of spinal cord fissuring.     

Syringomyelia secondary to congenital intraspinal lipoma

Preoperative evaluation using serial magnetic resonance imaging was performed on an infant with lumbosacral lipoma. Syrinx formation arising just above the lipoma was observed in conjunction with rapid growth of the lipoma. Definite shrinkage of syringomyelia was obtained after radical excision of the lipoma. The syrinx formation was possibly caused by compression from the extramedullary lipoma.     

Endonasal endoscopic resection of the odontoid process in a nonachondroplastic dwarf with juvenile rheumatoid arthritis: feasibility of the approach and utility of the intraoperative Iso-C three-dimensional navigation. Case report

The authors report a case of a nonachondroplastic dwarf with severe basilar invagination and compression of the cervicomedullary junction (CMJ) due to juvenile rheumatoid arthritis. Initially excellent reduction of the invagination and decompression of the CMJ was achieved using posterior fixation. However, 1 month postoperatively symptoms recurred and the authors found imaging evidence of recurrence as well. The patient subsequently underwent an endoscopic transnasal resection of the dens with assistance of Iso-C navigation. He recovered well and tolerated regular diet on postoperative Day 2.     

Endoscopic third ventriculostomy for treatment of noncommunicating syringomyelia associated with a Chiari I malformation and hydrocephalus: case report and pathophysiological considerations

OBJECTIVE AND IMPORTANCE: A Chiari I malformation associated with syringomyelia and hydrocephalus is a rare condition. We report the successful use of endoscopic third ventriculostomy for the treatment of this pathological entity. The successful use of this technique in such a case has not been previously described, and the results allow us to speculate on the pathophysiological mechanism involved. CLINICAL PRESENTATION: A 34-year-old woman presented with headaches, a motor deficit of the right upper limb, and gait dyspraxia. Magnetic resonance imaging scans demonstrated dilation of all ventricles, compression of the retrocerebellar cerebrospinal fluid space, downward displacement of the tonsils, and syringomyelia. Syringomyelia involved the cervicodorsal cord below C3, with a syrinx-free segment between C1 and C3 and no enlargement of the rostral part of the central canal. INTERVENTION: Endoscopic third ventriculostomy resulted in prompt improvement of the clinical symptoms. Postoperative magnetic resonance imaging scans demonstrated shrinkage of the syrinx and return of the cerebellar tonsils to their physiological positions. CONCLUSION: This experience demonstrates that endoscopic third ventriculostomy, which is a simple, safe technique, may be the treatment of choice for associated Chiari I malformations, hydrocephalus, and syringomyelia (even the noncommunicating type).     

An autopsy case of syringomyelia associated with Chiari malformation and basilar impression

The authors report one autopsy case of syringomyelia associated with Chiari malformation and basilar impression. The pathogenesis of syringomyelia in our case is discussed. This 37-year-old man complained of progressive difficulty in swallowing and walking for two years. He had noticed dysarthria for six months before admission. (Examination) Neurological examination showed dysarthria, down beat nystagmus, disturbance of IXth nerve, Xth nerve and XIth nerve, and cerebellar ataxia. Deep tendon reflexes were hyperactive in the upper and lower extremities. Babinski's sign was positive bilaterally. Neuroradiological examination demonstrated basilar impression and Chiari malformation. (Operation) Suboccipital craniectomy and laminectomy of upper cervical vertebra were performed with dural plasty. Postoperatively he acquired some improvement, but soon after he was worse. He died of respiratory disturbance. (Postmortem examination) Though the central canal was obliterated at the C4 level, the syrinx extended from the C5 to Th7 level. From the C5 to C8, the syrinx was present in the areas of central gray matter, extending into the left dorsal horn, where it communicated with subarachnoid space. Furthermore, the abnormal vessels were noticeable around the syrinx. At the Th2 level, they were also shown in central grey matter where no syrinx existed. (Conclusion) The etiology of syringomyelia in our case was not explained by Gardner's hydrodynamic theory. We suggested that intramedullary abnormal vessels played an important part for the formation of the syringomyelia.     

Surgery for posttraumatic syringomyelia： a retrospective study of seven patients

Objective： To analyze retrospectively the clinical symptoms, signs, radiological findings and results of treatment of posttraumatic syringomyelia. Methods： The data of 7 patients with posttraumatic syringomyelia confirmed by computerized tomography （CT） and magnetic resonance imaging （MRI） in our hospital between 1999 and 2004 were reviewed retrospectively. The patients underwent decompressive laminectomy or syringo-subarachnoid （S-S） shunting with microsurgery. Long-term follow-up was available （range： 13-65 months）. Results： The major dinical manifestations of posttraumatic syringomyelia usually included the onset of increasing signs and the development of new symptoms after an apparently stable period. The clinical symptoms included pain, sensory disturbance, weakness, and problems in autonomic nerves. Syrinx existed merely at the cervical level in 4 cases and extended downward to the thoracic levels in the other 3 cases. One case underwent decompressive laminectomy, 6 cases were treated by S-S shunting. During the early postoperative period, all the patients showed an improvement of symptoms of syrinx without major complication or death. The decreased size or collapse of the syrinx was demonstrated by postoperative MRI. Conclusions ： Posttraumatic syringomyelia is a disabling sequela of spinal cord injury, developing months to years after spinal injury. MRI is the standard diagnostic technique for syringomyelia. The patients with posttraunmtic syringomyelia combined with progressive neurological deterioration should be treated with operations. S-S shunting procedure is effective in some patients with posttraumatic syringomyelia. Decompressive procedure may be an alternative primary surgical treatment for patients with kyphosis and cord compression.     

Decompression of the spinal subarachnoid space as a solution for syringomyelia without Chiari malformation

STUDY DESIGN: Review and analysis of seven cases of syringomyelia treated surgically. OBJECTIVE: To demonstrate the beneficial role of decompressive surgery for the altered cerebrospinal fluid (CSF) flow dynamics in syringomyelia not associated with Chiari I malformation. A comparison between the pre- and post-operative syrinx size and CSF flow in the subarachnoid space was made using cine-mode magnetic resonance imaging (cine-MRI) and then correlated with clinical improvement. SETTING: University Hospital, Seoul, Korea. METHODS: Conventional spinal MRI and cine-MRI were performed in the region of CSF flow obstruction preoperatively in seven patients with syringomyelia not associated with Chiari I malformation. The group consisted of one case of syrinx with post-traumatic compression fracture, one case of post-traumatic arachnoiditis, two cases of holocord syrinx associated with hydrocephalus without Chiari malformation, one case of syrinx with post-traumatic pseudomeningeal cyst, one case of post-laminectomy kyphosis-associated syringomyelia and one case of post-tuberculous arachnoiditis syringomyelia. Based on the preoperative cine-MRI, the types of surgery appropriate to correct the CSF flow obstruction were chosen: decompressive laminectomy-adhesiolysis and augmentation duraplasty in arachnoiditis cases, ventriculoperitoneal shunt for hydrocephalus, cyst extirpation in pseudomeningeal cyst and both anterior and posterior decompression-fusion in the case of post-laminectomy kyphosis. A syrinx-draining shunt operation was performed in three cases; where the syringomyelia was associated with post-traumatic compression fracture refractory to a previous decompression, where hydrocephalus was present in which the decompression by ventriculoperitoneal shunt was insufficient and where post-traumatic arachnoiditis was present in which the decompression was impossible due to diffuse adhesion. Change in syrinx size was evaluated with post-operative MRI in all seven cases and restoration of flow dynamics was evaluated with cine-MRI in three of the cases, two patients with clinical improvement and one patient with no change of clinical status, respectively. RESULTS: Four out of seven patients showed symptomatic improvement after each decompressive operation. In the remaining three cases, reconstruction of the spinal subarachnoid space was not possible due to diffuse adhesion or was not the main problem as in the patient with syrinx associated with hydrocephalus who had to undergo a shunt operation. One of these three patients showed clinical improvement after undergoing syringosubarachnoid shunt. A decrease of syrinx size was observed in only two out of the five patients who showed clinical improvement after treatment. Of these five patients, two patients underwent post-operative cine-MRI and the restoration of normal CSF flow dynamics was noted in both patients. Of the remaining two patients, one underwent post-operative cine-MRI and there was no change in the CSF flow dynamics evident. CONCLUSION: These results suggest that the restoration of CSF flow dynamics between the syrinx and the subarachnoid space by decompressive operation is more effective than simple drainage of the syrinx cavity itself in the treatment of syringomyelia without Chiari malformation.     

Acute deterioration in occult Chiari malformation following missile spinal trauma. Case report

Patients with Chiari malformation (CM) Type I typically experience chronic, slowly progressive symptoms. Rarely, however, do they suffer acute neurological deterioration following an iatrogenic decrease in caudal cerebrospinal fluid pressure due to, for example, a lumbar puncture. To our knowledge, acute neurological deterioration following missile spinal injury in CM has not been previously described. The authors report on a 16-year-old girl who was shot in the abdomen and lumbar spine. Although neurologically intact on initial workup, she developed precipitous quadriplegia and apnea in a delayed fashion. Tonsillar herniation with medullary compression and cerebellar infarction was diagnosed on magnetic resonance imaging. Suboccipital decompression resulted in significant neurological improvement. Well-formed tonsillar ectopia diagnosed at surgery suggested a preexisting CM. The authors conclude that missile spinal trauma can precipitate medullary compression and acute neurological decline, especially in patients with preexisting tonsillar ectopia. Immediate operative decompression to relieve impaction at the cervicomedullary junction can result in significant neurological recovery.     

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.     

Disproportionately large communicating fourth ventricle with syringomyelia: case report

A 13-year-old boy presented with syringomyelia associated with disproportionately large communicating fourth ventricle (DLCFV) manifesting as symptoms attributable to hydrocephalus and characteristic posterior fossa symptoms. Magnetic resonance imaging demonstrated remarkable dilation of the fourth ventricle and syringomyelia. Ventriculoperitoneal shunting completely resolved all symptoms as well as the ventricular and spinal cord abnormalities. Pre- and postoperative cine magnetic resonance imaging revealed the change of cerebrospinal fluid flow signal in the area of the foramen magnum. We concluded that the syringomyelia could be described as enlargement of the central canal with DLCFV.     

Surgical treatment of syringomyelia: favorable results with syringosubarachnoid shunting

The authors review the clinical course of 29 patients who underwent syringosubarachnoid shunting for syringomyelia. Twenty-two patients presented hindbrain-related syringomyelia; seven patients had non-hindbrain-related syringomyelia secondary to trauma (four cases) and to spinal arachnoiditis (three cases). The surgical technique is described in detail. All patients showed postoperative deflation or collapse of the syrinx at follow-up magnetic resonance imaging evaluation. Symptoms stabilized in 17 cases (59%); 9 cases (31%) showed improvement in the neurological function; 3 cases (10%) presented delayed neurological deterioration, probably owing to spinal cord ischemia.     

Posterior occipitocervical fixation under skull-femoral traction for the treatment of basilar impression in a child with Klippel-Feil syndrome

We present the case of a 15-year-old boy with symptoms due to Klippel-Feil syndrome. Radiographs and CT scans demonstrated basilar impression, occipitalisation of C1 and fusion of C2/C3. MRI showed ventral compression of the medullocervical junction. Skull traction was undertaken pre-operatively to determine whether the basilar impression could be safely reduced. During traction, the C3/C4 junction migrated 12 mm caudally and spasticity resolved. Peri-operative skull-femoral traction enabled posterior occipitocervical fixation without decompression. Following surgery, cervical alignment was restored and spasticity remained absent. One year after surgery he was not limited in his activities. The surgical strategy for patients with basilar impression and congenital anomalies remains controversial. The anterior approach with decompression is often recommended for patients with ventral compression of the medullocervical region, but such procedures are technically demanding and carry a significant risk of complications. Our surgical strategy was an alternative solution. Prior to a posterior cervical fixation, without decompression, skull traction was used to confirm that the deformity was reducible and effective in resolving associated myelopathy.