Endoscopic Endonasal Approach to Foramen Magnum Meningioma­Technical Note and Case Example

Foramen magnum (FM) tumors represent one of the most complex cases for the neurosurgeon, due to their location in a very anatomically complex region surrounded by the brainstem and the lower cranial nerves, by bony elements of the craniocervical junction, and by the vertebrobasilar vessels. Currently, the open approach of choice is a lateral extension of the posteriormidline approach including far lateral, and extremelateral routes. However, the transoraltranspharyngeal approach remains the treatment of choice in cases of diseases affecting the craniocervical junction. For very selective cases, the endoscopic endonasal route to this region is another option.We present a case of a ventral FM meningioma treated exclusively with the endoscopic endonasal approach.

A comprehensive review of the clivus: anatomy, embryology, variants, pathology, and surgical approaches.

INTRODUCTION: The clivus is a bony structure formed by the fusion of the basioccipital and basispheniod bone at the sphenooccipital synchondrosis. This downward sloping structure from the dorsum sellae to the foramen magnum is derived from mesoderm and ectoderm properties. METHODS: This comprehensive review of the clivus will discuss its basic anatomy, embryology, pathological findings, and surgical implications. The clivus is an endochondral bone, formed under two processes; first, a cartilaginous base is developed, and it is secondly reabsorbed and replaced with bone. Knowledge of its embryological structure and growth of development will clarify the pathogenesis of anatomical variants and pathological findings of the clivus. CONCLUSIONS: Understanding the anatomy including proximity to anatomical structures, adjacent neurovasculature properties, and anatomical variants will aid neurosurgeons in their surgical management when treating pathological findings around the clivus.

Displasia do occipital em cães - revisão de literatura / Occipital dysplasia in dogs - literature review / Displasia occipital en perros - revisión de la literatura

O forame magno é normalmente de formato arredondado ou ovalado e apresenta diâmetro similar ao do forame vertebral do atlas. A displasia do occipital é caracterizada por um alargamento dorsal do forame magno causado pela ossificação incompleta do osso supraoccipital, sendo observada em cães de raças de pequeno porte e braquicefálicos. Divergências sobre a relevância clínica da displasia do occipital em cães estão presentes na literatura, sendo questionável se essa condição é apenas uma variação anatômica ou realmente uma enfermidade. O presente trabalho tem o objetivo de esclarecer aspectos relacionados à displasia do occipital por meio de uma revisão bibliográfica sobre esse tema, abordando tópicos sobre a anatomia da junção atlanto-occipital, assim como os aspectos clínicos e diagnósticos da displasia do occipital em cães.(AU)

The foramen magnum is normally rounded or oval in shape and has a similar diameter to the vertebral foramen of the atlas. Occipital dysplasia is observed in small breed and brachycephalic dogs, and is characterized by a dorsal widening of the foramen magnum caused by an incomplete ossification of the supraoccipital bone. There are divergent opinions in the literature regarding the clinical relevance of occipital dysplasia in dogs, and doubts remain as to whether this presentation is only an anatomical variation or an actual disease. The objective of this paper is to clarify aspects related to occipital dysplasia by means of a literature review on this subject, focusing on the anatomy of the atlanto-occipital junction, as well as the clinical and diagnostic aspects of occipital dysplasia in dogs.(AU)

El foramen magno normalmente tiene un formato redondeado u ovalado, y presenta un diámetro similar al foramen vertebral del atlas. La displasia occipital se caracteriza por un ensanchamiento dorsal del foramen magno causado por la osificación incompleta del hueso supraoccipital, y se puede observar en razas pequeñas y en braquicéfalos. Existen diferentes opiniones en la literatura sobre la importancia clínica de la displasia occipital en los perros, y puede cuestionarse si esa condición es sólo una variación anatómica o si realmente es una enfermedad. Este trabajo tiene como objetivo aclarar ciertos aspectos relacionados con la displasia occipital a través de una revisión de la bibliografía relacionada con el tema, abordando tópicos sobre la anatomía de la unión atlanto-occipital, así como también aspectos clínicos y diagnósticos de la displasia occipital en los perros.(AU)

Displasia do occipital em cães - revisão de literatura / Occipital dysplasia in dogs - literature review / Displasia occipital en perros - revisión de la literatura

O forame magno é normalmente de formato arredondado ou ovalado e apresenta diâmetro similar ao do forame vertebral do atlas. A displasia do occipital é caracterizada por um alargamento dorsal do forame magno causado pela ossificação incompleta do osso supraoccipital, sendo observada em cães de raças de pequeno porte e braquicefálicos. Divergências sobre a relevância clínica da displasia do occipital em cães estão presentes na literatura, sendo questionável se essa condição é apenas uma variação anatômica ou realmente uma enfermidade. O presente trabalho tem o objetivo de esclarecer aspectos relacionados à displasia do occipital por meio de uma revisão bibliográfica sobre esse tema, abordando tópicos sobre a anatomia da junção atlanto-occipital, assim como os aspectos clínicos e diagnósticos da displasia do occipital em cães.

The foramen magnum is normally rounded or oval in shape and has a similar diameter to the vertebral foramen of the atlas. Occipital dysplasia is observed in small breed and brachycephalic dogs, and is characterized by a dorsal widening of the foramen magnum caused by an incomplete ossification of the supraoccipital bone. There are divergent opinions in the literature regarding the clinical relevance of occipital dysplasia in dogs, and doubts remain as to whether this presentation is only an anatomical variation or an actual disease. The objective of this paper is to clarify aspects related to occipital dysplasia by means of a literature review on this subject, focusing on the anatomy of the atlanto-occipital junction, as well as the clinical and diagnostic aspects of occipital dysplasia in dogs.

El foramen magno normalmente tiene un formato redondeado u ovalado, y presenta un diámetro similar al foramen vertebral del atlas. La displasia occipital se caracteriza por un ensanchamiento dorsal del foramen magno causado por la osificación incompleta del hueso supraoccipital, y se puede observar en razas pequeñas y en braquicéfalos. Existen diferentes opiniones en la literatura sobre la importancia clínica de la displasia occipital en los perros, y puede cuestionarse si esa condición es sólo una variación anatómica o si realmente es una enfermedad. Este trabajo tiene como objetivo aclarar ciertos aspectos relacionados con la displasia occipital a través de una revisión de la bibliografía relacionada con el tema, abordando tópicos sobre la anatomía de la unión atlanto-occipital, así como también aspectos clínicos y diagnósticos de la displasia occipital en los perros.

Foramen magnum meningiomas: surgical treatment in a single public institution in a developing country.

OBJECTIVE: To analyze the clinical outcome of patients with foramen magnum (FM) meningiomas. METHOD: Thirteen patients (11 Feminine / 2 Masculine with FM meningiomas operated on through lateral suboccipital approach were studied. Clinical outcome were analyzed using survival (SC) and recurrence-free survival curves (RFSC). RESULTS: All tumors were World Health Organization grade I. Total, subtotal and partial resections were acchieved in 69.2%, 23.1% and 7.7%, respectively, and SC was better for males and RFSC for females. Tumor location, extent of resection and involvement of vertebral artery/lower cranial nerves did not influence SC and RFSC. Recurrence rate was 7.7%. Operative mortality was 0. Main complications were transient (38.5%) and permanent (7.7%) lower cranial nerve deficits, cerebrospinal fluid fistula (30.8%), and transient and permanent respiratory difficulties in 7.7% each. CONCLUSIONS: FM meningiomas can be adequately treated in public hospitals in developing countries if a multidisciplinary team is available for managing postoperative lower cranial nerve deficits.

Foramen magnum meningiomas: surgical treatment in a single public institution in a developing country / Meningiomas do forame magno: tratamento cirúrgico em uma instituição pública em um país em desenvolvimento

Objective: To analyze the clinical outcome of patients with foramen magnum (FM) meningiomas. Method: Thirteen patients (11 Feminine / 2 Masculine with FM meningiomas operated on through lateral suboccipital approach were studied. Clinical outcome were analyzed using survival (SC) and recurrence-free survival curves (RFSC). Results: All tumors were World Health Organization grade I. Total, subtotal and partial resections were acchieved in 69.2%, 23.1% and 7.7%, respectively, and SC was better for males and RFSC for females. Tumor location, extent of resection and involvement of vertebral artery/lower cranial nerves did not influence SC and RFSC. Recurrence rate was 7.7%. Operative mortality was 0. Main complications were transient (38.5%) and permanent (7.7%) lower cranial nerve deficits, cerebrospinal fluid fistula (30.8%), and transient and permanent respiratory difficulties in 7.7% each. Conclusions: FM meningiomas can be adequately treated in public hospitals in developing countries if a multidisciplinary team is available for managing postoperative lower cranial nerve deficits. .

Objetivo: Analisar as evoluções clínicas de 13 pacientes com meningiomas do forame magno (FM). Método: Foram estudados 13 pacientes com meningiomas do FM (11 Feminino / 2 Masculino) operados por abordagem suboccipital lateral. As evoluções clínicas foram analisadas usando curvas de sobrevida (SC) e de sobrevida livre de doença (RFSC). Resultados: Os 13 tumores eram Grau I da Organização Mundial de Saúde. Ressecções total, subtotal and parcial foram obtidas em 69,2%, 23,1 e 7,7%, respectivamente. A SC foi melhor para homens e a RFSC foi melhor para mulheres. Localização/ extensão da ressecção/envolvimento da artéria vertebral/nervos cranianos baixos não influenciaram a SC/RFSC. A taxa de recorrência foi 7,7%. A mortalidade operatória foi zero. As principais complicações foram déficits de nervos cranianos baixos transitórios (38,5%) e permanentes (7,7%); fístula de líquido cefalorraquidiano (30,8%) e dificuldades respiratórias transitórias e permanentes em 7,7% cada. Conclusões: Meningiomas do FM podem ser adequadamente tratados em hospitais públicos em países em desenvolvimento se houver uma equipe multidisciplinar para cuidar de déficits de nervos cranianos baixos pós-operatórios. .

Sleep-related respiratory abnormalities and arousal pattern in achondroplasia during early infancy.

OBJECTIVE: To assess sleep-disordered breathing (SDB), sleep architecture, and arousal pattern in infants with achondroplasia and to evaluate the relationship between foramen magnum size and the severity of SDB. STUDY DESIGN: A retrospective review of polysomnographic recordings and medical records was performed in infants with achondroplasia and in aged-matched control subjects. All studies were re-scored with the emphasis on respiratory events, sleep state, and arousals. In addition, the neuroimaging study of the brain (magnetic resonance imaging) was reviewed to evaluate foramen magnum diameters and to assess their relationship to SDB. RESULTS: Twenty-four infants met the criteria for entry into analysis, 12 infants with achondroplasia (A) and 12 control infants (C). There was no significant difference in age or sex. Infants with achondroplasia had a significant increase in total respiratory disturbance index (RDI; A, 13.9 +/- 10.8 versus C, 2.0 +/- 0.9; P < .05). However, there was no significant difference in percentages of active sleep, quiet sleep, or sleep efficiency. Analysis of arousals demonstrated that infants with achondroplasia had a significant decrease in both spontaneous arousal index (A, 10.5 +/- 3.5/hr versus C, 18.6 +/- 2.7; P < .0001) and respiratory arousals (A, 10.3% +/- 6.3% versus C, 27.5 +/- 9.5%; P < .0001). Evaluation of foramen magnum dimensions demonstrated smaller foramen magnum size, but there were no significant correlations between anteroposterior or transverse diameters and RDI. CONCLUSION: Infants with achondroplasia have significant SDB during early infancy. SDB in infants with achondroplasia is not associated with alteration in sleep architecture, possibly because of attenuation of the arousal response. We speculate that the concomitant increased apneic events and decreased arousal response will lead to vulnerability in these infants and may underlie the pathophysiologic mechanism of sudden unexpected death in this population.

Surgical management of foramen magnum meningiomas.

The objective of the study is to describe our experience in the surgical management of foramen magnum meningiomas with regard to the clinical-radiological findings, the surgical approach and the outcomes after mid-term follow up. Over a 5-year period, 15 patients presenting with meningiomas of the foramen magnum underwent surgical treatment. The medical records were reviewed in order to analyze the clinical-radiological aspects, as well as the surgical approach and the outcomes. Based on the preoperative magnetic resonance imaging exams, the tumors were classified as anterior or anterolateral in the axial slices and clivospinal or spinoclival in the sagittal slices. The lateral approach was used in all cases. However, the extent of bone removal and the management of the vertebral artery were tailored to each patient. Fourteen patients were females, and one was male, ranging in age from 42 to 74 years (mean 55,9 years). The occipital condyle was partially removed in eight patients, and in seven patients, removal was not necessary. Total removal of the tumor was achieved in 12 patients, subtotal in two, and partial resection in one patient. Postoperative complications occurred in two patients. Follow-up ranged from 6 to 56 months (mean 23.6 months).There was no surgical mortality in this series. The extent of the surgical approach to foramen magnum meningiomas must be based on the main point of dural attachment and tailored individually case-by-case. The differentiation between the clivospinal and spinoclival types, as well as anterior and anterolateral types, is crucial for the neurosurgical planning of foramen magnum meningiomas.

Chordoid meningioma of the foramen magnum in a child: a case report and review of the literature.

We report a 3-year-6-month-old boy with chordoid meningioma in the foramen magnum. Chordoid meningioma represents between 0.5 and 1.0% of all meningiomas, and it is frequently located in the supratentorial region. The patient started with an episode of instability, falls, and headache; after which, he developed cuadriparesis, cervical pain, and neck stiffness, which slightly improved after medical treatment, so he was referred to our hospital. Physical examination revealed left hemiparesis and cervical muscle spasm with left torticollis. Magnetic resonance imaging (MRI) demonstrated an intradural-extramedullary well-circumscribed, homogeneous enhancing mass, in the anterior part of the foramen magnum with cervical extension. The operative technique was the extreme-lateral craniocervical retrocondylar approach with total removal and dural coagulation. Histopathological examination demonstrated a chordoid meningioma, with meningotelial basophilic mucoid chordoma-like component in 80% of the tissue. The immunohistochemical stains were positive to epithelial membrane antigen, vimentin, and S-100 protein. At 10 months follow-up, the patient showed improvement in his neurological deficit with physical rehabilitation, and motor response in his extremities are now normal; neck stiffness with cervical spasm disappeared postoperatively. MRI showed no residual tumor. To our knowledge, this is the first report of a chordoid meningioma on the foramen magnum in a child.

Abordaje extremo lateral transcondilar para resecar un meningioma anterior del foramen magno / Extreme lateral transcondylar approach to resect an anterior foramen magnum meningioma

Objetivo. Describir el abordaje extremo lateral transcondilar realizado para resecar un meningioma del sector aterior del foramen magno. Descripción. Mujer de 24 años con una tetraparesia a prediminio derecho y déficit de los nervios craneanos IX, X y XI del lado derecho, de 9 meses de evolución. La resonancia magnética mostró un proceso expansivo a nivel del sector anterior del foramen magno (isointenso en T1 y T2, captando en forma homogénea y bien marcada luego de la administración del gadolinio). Intervención. En diciembre de 2005 se realizó la cirugía (abordaje extremolateral transcondilar), con resección completa de la lesión. Anatomía patológica: meningioma cordoide. La paciente evolucionó mejorando completamente de su clínica neurológica, encontrándose actualente sin ninguna secuela. Conclusión. En este caso el abordaje extremo lateral transcondilar fue la vía de elección para resecar completamente el meningioma del sector anterior del foramen magno. Palabras clave: abordaje extremolateral, cóndilo occipital, foramen magno, meningioma

Objective: To describe the far-lateral transcondylar approach performed toremove a meningioma of the anterior portion of the foramen magnum. Description: A woman, 24-years old, with tetraparesis, greater in the right side, and paresis of the IX, X and XI right cranial nerves, with a 9 months history. The MRI showed a tumor in the anterior aspect of the foramen magnum (isointense in T1 and T2, with homogeneous enhace after galolinium administration). Intervention. In December 2005 the surgery was performed (far-lateral transcondylar approach), with complete removal of the lesion. Histology: cordoid meningioma. The patient had a good outcome, with complete recovery of her neurological deficits. In the last control, she was asymptomatic. Conclusion. In this case, the far-lateral transcondylar was the most appropiate approach to completely resect a meningioma of the anterior portion of the foramen magnum. Key words: condyle, far-lateral approach, foramen magnum, meningioma.

Abordaje extremo lateral transcondilar para resecar un meningioma anterior del foramen magno / Extreme lateral transcondylar approach to resect an anterior foramen magnum meningioma

Objetivo. Describir el abordaje extremo lateral transcondilar realizado para resecar un meningioma del sector aterior del foramen magno. Descripción. Mujer de 24 años con una tetraparesia a prediminio derecho y déficit de los nervios craneanos IX, X y XI del lado derecho, de 9 meses de evolución. La resonancia magnética mostró un proceso expansivo a nivel del sector anterior del foramen magno (isointenso en T1 y T2, captando en forma homogénea y bien marcada luego de la administración del gadolinio). Intervención. En diciembre de 2005 se realizó la cirugía (abordaje extremolateral transcondilar), con resección completa de la lesión. Anatomía patológica: meningioma cordoide. La paciente evolucionó mejorando completamente de su clínica neurológica, encontrándose actualente sin ninguna secuela. Conclusión. En este caso el abordaje extremo lateral transcondilar fue la vía de elección para resecar completamente el meningioma del sector anterior del foramen magno. Palabras clave: abordaje extremolateral, cóndilo occipital, foramen magno, meningioma (AU)

Objective: To describe the far-lateral transcondylar approach performed toremove a meningioma of the anterior portion of the foramen magnum. Description: A woman, 24-years old, with tetraparesis, greater in the right side, and paresis of the IX, X and XI right cranial nerves, with a 9 months history. The MRI showed a tumor in the anterior aspect of the foramen magnum (isointense in T1 and T2, with homogeneous enhace after galolinium administration). Intervention. In December 2005 the surgery was performed (far-lateral transcondylar approach), with complete removal of the lesion. Histology: cordoid meningioma. The patient had a good outcome, with complete recovery of her neurological deficits. In the last control, she was asymptomatic. Conclusion. In this case, the far-lateral transcondylar was the most appropiate approach to completely resect a meningioma of the anterior portion of the foramen magnum. Key words: condyle, far-lateral approach, foramen magnum, meningioma.(AU)

Abordaje extremo lateral transcondilar para resecar un meningioma anterior del foramen magno / Extreme lateral transcondylar approach to resect an anterior foramen magnum meningioma

Objetivo. Describir el abordaje extremo lateral transcondilar realizado para resecar un meningioma del sector aterior del foramen magno. Descripción. Mujer de 24 años con una tetraparesia a prediminio derecho y déficit de los nervios craneanos IX, X y XI del lado derecho, de 9 meses de evolución. La resonancia magnética mostró un proceso expansivo a nivel del sector anterior del foramen magno (isointenso en T1 y T2, captando en forma homogénea y bien marcada luego de la administración del gadolinio). Intervención. En diciembre de 2005 se realizó la cirugía (abordaje extremolateral transcondilar), con resección completa de la lesión. Anatomía patológica: meningioma cordoide. La paciente evolucionó mejorando completamente de su clínica neurológica, encontrándose actualente sin ninguna secuela. Conclusión. En este caso el abordaje extremo lateral transcondilar fue la vía de elección para resecar completamente el meningioma del sector anterior del foramen magno. Palabras clave: abordaje extremolateral, cóndilo occipital, foramen magno, meningioma (AU)

Objective: To describe the far-lateral transcondylar approach performed toremove a meningioma of the anterior portion of the foramen magnum. Description: A woman, 24-years old, with tetraparesis, greater in the right side, and paresis of the IX, X and XI right cranial nerves, with a 9 months history. The MRI showed a tumor in the anterior aspect of the foramen magnum (isointense in T1 and T2, with homogeneous enhace after galolinium administration). Intervention. In December 2005 the surgery was performed (far-lateral transcondylar approach), with complete removal of the lesion. Histology: cordoid meningioma. The patient had a good outcome, with complete recovery of her neurological deficits. In the last control, she was asymptomatic. Conclusion. In this case, the far-lateral transcondylar was the most appropiate approach to completely resect a meningioma of the anterior portion of the foramen magnum. Key words: condyle, far-lateral approach, foramen magnum, meningioma.(AU)

Basilar invagination as a sequela of multisystem Langerhans' cell histiocytosis.

We report the presence of basilar invagination, an unexpected and previously undescribed abnormality of the skull base, in 7 of 38 long-term survivors of multisystem Langerhans' cell histiocytosis. The abnormality is acquired, but its pathogenesis is uncertain.

Cerebral syrinx with Chiari I malformation.

A 13-year-old female presented with acute left gaze paralysis. MRI revealed hydrosyringomyelia (HSM) with syringobulbia in the left pons extending cephalad into the centrum semiovale. A suboccipital craniotomy was performed and the foramen of Magendie was imperforate. Ocular movements normalized in 2 months and postoperative MRI confirmed resolution of the cerebral syrinx and syringobulbia and diminished HSM. This case represents an extreme example of the altered spinal fluid dynamics with Chiari I malformation. Theories on HSM are reviewed.