Surgical approaches to foramen magnum meningioma--report of three cases. (25/83)

Although foramen magnum meningiomas are usually removable, their location poses considerable surgical risk. The authors present three cases of foramen magnum meningioma. The first involved a ventral type tumor extending to the second cervical body. Following bilateral mandibulotomy, surgery was performed via the anterior transoral approach and the tumor was totally removed. Nine days postoperatively, she developed meningitis, which was successfully treated with antibiotics. The second patient's tumor was dorsal type and was deeply embedded in the lateral part of the vermis. The tumor was totally removed via the midline suboccipital approach and she recovered uneventfully, with only slight upper-extremity paresthesia. In the third case, the tumor was ventral type and situated mainly in the clivus. Craniotomy was performed by the bilateral suboccipital approach and extended nearly to the jugular tubercle. The tumor, which severely displaced the lower cranial and upper cervical nerves, was totally removed. The postoperative course was lengthy and complicated. Artificial ventilation was required for 2 months, and difficulty in swallowing persisted during long-term follow-up. As illustrated by the second case, dorsal and lateral type foramen magnum meningiomas can usually be removed via the lateral suboccipital approach. In the case of ventral type tumors, the anterior transoral approach entails the risk of infection, as occurred in the first case. The authors conclude that the lateral suboccipital approach is preferable; craniotomy extending to the jugular tubercle lowers the risk of brainstem damage.  (+info)

Superior odontoid migration in the Klippel-Feil patient. (26/83)

Klippel-Feil syndrome (KFS) is an uncommon condition noted primarily as congenital fusion of two or more cervical vertebrae. Superior odontoid migration (SOM) has been noted in various skeletal deformities and entails an upward/vertical migration of the odontoid process into the foramen magnum with depression of the cranium. Excessive SOM could potentially threaten neurologic integrity. Risk factors associated with the amount of SOM in the KFS patient are based on conjecture and have not been addressed in the literature. Therefore, this study evaluated the presence and extent of SOM and the various risk factors and clinical manifestations associated therein in patients with KFS. Twenty-seven KFS patients with no prior history of surgical intervention of the cervical spine were included for a prospective radiographic and retrospective clinical review. Radiographically, McGregor's line was utilized to evaluate the degree of SOM. Anterior and posterior atlantodens intervals (AADI/PADI), number of fused segments (C1-T1), presence of occipitalization, classification-type, and lateral and coronal cervical alignments were also evaluated. Clinically, patient demographics and presence of cervical symptoms were assessed. Radiographic and clinical evaluations were conducted by two independent blinded observers. There were 8 males and 19 females with a mean age of 13.5 years at the time of radiographic and clinical assessment. An overall mean SOM of 5.0 mm (range = -1.0 to 19.0 mm) was noted. C2-C3 (74.1%) was the most commonly fused segment. A statistically significant difference was not found between the amount of SOM to age, sex-type, classification-type, AADI, PADI, and lateral cervical alignment (P > 0.05). A statistically significant greater amount of SOM was found as the number of fused segments increased (r = 0.589; P = 0.001) and if such levels included occipitalization (r = 0.616; P = 0.001). A statistically significant greater amount of SOM was also found with an increase in coronal cervical alignment (r = 0.413; P = 0.036). Linear regression modeling further supported these findings as the strongest predictive variables contributing to an increase in SOM. A 7.20 crude relative risk (RR) ratio [95% confidence interval (CI) = 1.05-49.18; risk differences (RD) = 0.52] was noted in contributing to a SOM greater than 4.5 mm if four or more segments were fused. Adjusting for coronal cervical alignment greater than 10 degrees , five or more fused segments were found to significantly increase the RR of a SOM greater than 4.5 mm (RR = 4.54; 95% CI = 1.07-19.50; RD = 0.48). The RR of a SOM greater than 4.5 mm was more pronounced in females (RR = 1.68; 95% CI = 0.45-6.25; RD = 0.17) than in males. Eight patients (29.6%) were symptomatic, of which symptoms in two of these patients stemmed from a traumatic event. However, a statistically significant difference was not found between the presence of symptoms to the amount of SOM and other exploratory variables (P > 0.05). A mean SOM of 5.0 mm was found in our series of KFS patients. In such patients, increases in the number of congenitally fused segments and in the degree of coronal cervical alignment were strongly associated risk factors contributing to an increase in SOM. Patients with four or greater congenitally fused segments had an approximately sevenfold increase in the RR in developing SOM greater than 4.5 mm. A higher RR of SOM more than 4.5 mm may be associated with sex-type. However, 4.5 mm or greater SOM is not synonymous with symptoms in this series. Furthermore, the presence of symptoms was not statistically correlated with the amount of SOM. The treating physician should be cognizant of such potential risk factors, which could also help to indicate the need for further advanced imaging studies in such patients. This study suggests that as motion segments diminish and coronal cervical alignment is altered, the odontoid orientation is located more superiorly, which may increase the risk of neurologic sequelae.  (+info)

Foramen magnum decompression for syringomyelia associated with basilar impression and Chiari I malformation--report of three cases. (27/83)

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.  (+info)

Giant dumbbell foramen magnum neurinomas presenting as posterior neck masses: single-stage removal by posterior midline approach. (28/83)

Two patients with giant dumbbell foramen magnum neurinomas are reported. The intradural component was located anterior to the cervicomedullary junction while the extradural and extraspinal portion of the tumor had grown large enough to present as a neck swelling. In both patients total surgical removal was achieved by a single-stage posterior midline approach. Both patients had complete neurological recovery.  (+info)

Foramen magnum meningiomas: detailed surgical approaches and technical aspects at Lariboisiere Hospital and review of the literature. (29/83)

Foramen magnum meningiomas are challenging tumors, requiring special considerations because of the vicinity of the medulla oblongata, the lower cranial nerves, and the vertebral artery. After detailing the relevant anatomy of the foramen magnum area, we will explain our classification system based on the compartment of development, the dural insertion, and the relation to the vertebral artery. The compartment of development is most of the time intradural and less frequently extradural or both intraextradural. Intradurally, foramen magnum meningiomas are classified posterior, lateral, and anterior if their insertion is, respectively, posterior to the dentate ligament, anterior to the dentate ligament, and anterior to the dentate ligament with extension over the midline. This classification system helps to define the best surgical approach and the lateral extent of drilling needed and anticipate the relation with the lower cranial nerves. In our department, three basic surgical approaches were used: the posterior midline, the postero-lateral, and the antero-lateral approaches. We will explain in detail our surgical technique. Finally, a review of the literature is provided to allow comparison with the treatment options advocated by other skull base surgeons.  (+info)

Chiari 1 malformation with syringomyelia: correlation of phase-contrast cine MR imaging and outcome. (30/83)

AIM: This study was designed to determine the hemodynamics of cerebrospinal fluid flow in syringomyelia patients associated with Chiari I malformation using phase-contrast velocity-encoded-cine MRI and also to find out whether treatment outcomes may be predicted by these flow measurements. MATERIAL AND METHODS: Eighteen consecutive symptomatic patients with syringomyelia associated with Chiari 1 malformation were included. The PC VEC MRI was performed at the level of foramen magnum and syrinx cavity both preoperatively and 6 months postoperatively. Following surgery, the modified Asgari score was calculated, and the association between CSF flow pattern and clinical outcome was assessed. RESULTS: Evaluation of clinical symptoms at postoperative 6th month revealed improvement in 11 (61%) patients and stabilization in 5 (28%) patients whereas results were poor in 2 (11%) patients. Preoperative cine MRI flow studies showed a heterogeneous pattern at the foramen magnum level in all of the patients. Postoperative cine MR flow studies demonstrated the change from heterogeneous pattern to sinusoidal pattern in 11 patients and a decrease in heterogeneity in 7 patients. CONCLUSION: Our results indicate that CSF flow measurements using PC VEC MRI can give important information regarding the prognosis and follow-up of the patients with Chiari I malformation.  (+info)

Foramen magnum meningioma: Dysphagia of atypical etiology. (31/83)

INTRODUCTION: We present a case of a foramen magnum meningioma that highlights the importance of the neurologic exam when evaluating a patient with dysphagia. A 58-year-old woman presented with an 18-month history of progressive dysphagia, chronic cough and 30-pound weight loss. Prior gastroenterologic and laryngologic workup was unrevealing. RESULTS: Her neurologic examination revealed an absent gag reflex, decreased sensation to light touch on bilateral distal extremities, hyperreflexia, and tandem gait instability. Repeat esophagogastroduodenoscopy was normal, whereas laryngoscopy and video fluoroscopy revealed marked hypopharyngeal dysfunction. Brain magnetic resonance imaging demonstrated a 3.1 x 2.7 x 2.9 cm foramen magnum mass consistent with meningioma. The patient underwent neurosurgical resection of her mass with near complete resolution of her neurologic symptoms. Pathology confirmed diagnosis of a WHO grade I meningothelial meningioma. CONCLUSION: CNS pathology is an uncommon but impressive cause of dysphagia. Our case demonstrates the importance of a thorough neurologic survey when evaluating such a patient.  (+info)

Ossification of caroticoclinoid ligament and its clinical importance in skull-based surgery. (32/83)

CONTEXT: The medial end of the posterior border of the sphenoid bone presents the anterior clinoid process (ACP), which is usually accessed for operations involving the clinoid space and the cavernous sinus. The ACP is often connected to the middle clinoid process (MCP) by a ligament known as the caroticoclinoid ligament (CCL), which may be ossified, forming the caroticoclinoid foramen (CCF). Variations in the ACP other than ossification are rare. The ossified CCL may have compressive effects on the internal carotid artery. Thus, anatomical and radiological knowledge of the ACP and the clinoid space is also important when operating on the internal carotid artery. Excision of the ACP may be required for many skull-based surgical procedures, and the presence of any anomalies such as ossified CCL may pose a problem for neurosurgeons. CASE REPORT: We observed the presence of ossified CCL in a skull bone. A detailed radiological study of the CCL and the CCF was conducted. Morphometric measurements were recorded and photographs were taken. The ACP was connected to the MCP and was converted into a CCF. Considering the fact that standard anatomy textbooks do not provide morphological descriptions and radiological evaluations of the CCL, the present study may be important for neurosurgeons operating in the region of the ACP.  (+info)