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At least 19 recordsLinked to original sources
PubMed1983

[Proposal for the definition of "foramen magnum syndrome"--foramen magnum tumor and abnormalities].

The clinical appearance of foramen magnum tumor is protean and, even at the stage when serious neurological deficits are present, the lesions are often misdiagnosed as another disease, especially cervical spondylosis and multiple sclerosis, and patients may undergo improper concervative or even surgical treatments. The best guarantee against misdiagnosis, we believed, was to establish a definition of "Foramen Magnum Syndrome" to facilitate the recollection of its peculiar clinical findings. "Foramen Magnum Syndrome" is composed of: 1. Cape distribution of sensory loss; 2. Atrophy of the intrinsic muscles of the hands; 3. Neck or suboccipital pain; 4. Dysesthesia of the hands (numbness, tingling, and cold sensation); 5. Eleventh cranial nerve palsy; 6. Stereoanesthesia. (Remember the mnemonic CANDES or DESCAN) Among these, cape distribution of sensory loss, eleventh cranial nerve palsy and cold dysesthesia (not numbness or tingling sensation) are of great importance for topological diagnosis. We also pointed out the similarities between the clinical picture of syringomyelia and that of the advanced stage of foramen magnum tumor. The syringomyelic syndrome, often seen in Arnold-Chiari malformation and basilar impression, has been attributed to the concurrent syrinx of cervical cord. But the clinical analysis of foramen magnum tumors showed that this is not always true and that compressive lesions at the foramen magnum alone can cause syringomyelic syndrome.

Accessory Nerve↗
PubMed1990

Microanatomy of retia mirabilia of bowhead whale foramen magnum and mandibular foramen.

The morphology of vessels of the cervical rete mirabile near the region of the foramen magnum of the bowhead whale, Balaena mysticetus, as well as of retial vessels of the mandibular foramen was studied by light and transmission electron microscopy. A comparison of arterial and venous components of the mandibular rete revealed considerable arterial branching and arteriovenous anastomoses. Although the small arteries of bowhead retia contained the same layers found in nonretial arteries, several distinctive morphologic features were evident. These included wide separation by collagenous connective tissue and small size of individual smooth muscle cells of the tunica media. These myocytes also contained considerable perinuclear glycogen and communicated minimally with adjacent myocytes by small foot-like cytoplasmic appendages as well as branching of basement membranes. Ganglia-like neural plexuses were observed within the tunica media of arterial retia. Endothelial cells lining the intima demonstrated loose peripheral edges which frequently projected into the vessel lumen, and these cells rested upon a subjacent layer of reticular fibers. It is known for some species that the retial supply to the brain in whales largely supplants an internal carotid arterial supply and that the spinal cord is supplied by retia. The physiologic role of the bowhead mandibular retia remains unknown. The retia mirabilia of cetaceans are considered as one of the morphologic adaptations which modulate hemodynamics during diving and resurfacing. The morphologic features of these vessels in the bowhead whale, as revealed by electron microscopy, appear to reflect the capability to respond in a slow but sustained manner to diving, and the large glycogen deposits may help sustain vascular myocyte metabolism during prolonged submersion.

Animals↗
PubMed1990

Hoarseness as the sole presenting symptom of foramen magnum meningioma.

Foramen magnum tumours are rare. They may present with bizarre symptoms and mimic many conditions. We report a presentation with the sole complaint of hoarseness, never previously described in the literature. Voice returned to normal after surgical removal of the foramen magnum meningioma.

Aged↗
PubMed1989

Growth of the foramen magnum in achondroplasia.

Foramen magnum growth curves in achondroplasia and in the general population are presented. The achondroplastic foramen magnum is small at birth, and during the first year it has a severely impaired rate of growth especially in the transverse dimension. This markedly diminished growth results not only from abnormal endochondral bone growth but also because of abnormal placement and premature fusion of the synchondroses. Evaluation of the foramen magnum in achondroplasia should address absolute size of the transverse and sagittal dimensions, shape, and growth centers to determine growth potential of this area.

Achondroplasia↗
PubMed2000

Ventral foramen magnum meninigiomas.

OBJECT: Ventral foramen magnum meningiomas (VFMMs) are rare lesions that account for more than 3% of all meningiomas. These are among the most challenging of all meningiomas to treat. The authors comprehensively analyzed multiple features in a series of VFMMs. METHODS: A retrospective study was performed of 18 patients who harbored a meningioma in the ventral foramen magnum (mean follow-up period, 40 months) and underwent surgery via a transcondylar approach. Sixteen patients underwent surgery for the first time: 12 underwent gross-total (75%), two near-total (12.5%), and two subtotal (12.5%) tumor removal. The remaining two patients were treated for a recurrent tumor. After obtaining postoperative Karnofsky Performance Scale (KPS) scores at follow up, statistically significant improvement was demonstrated compared with the preoperative scores. The extent of surgery and higher preoperative KPS scores were variables that showed statistically significant favorable influence on outcome. Ninth and 10th cranial nerve deficits were the most common complications contributing to a prolonged hospital stay. There were no perioperative deaths. Four patients died during the follow-up period. The first patient died of multiple myeloma. The second patient, in whom surgery was performed to treat a recurrent tumor, died 3 years after the surgery of new tumor recurrence at the age of 80 years. The remaining two patients died 1.5 and 5 months postsurgery of pulmonary embolus and endocarditis, respectively. CONCLUSIONS: Ventral foramen magnum meningiomas can be radically resected in a majority of patients, with frequent but transient morbidity caused by lower cranial nerve deficits. Radical removal of a recurrent tumor provides a relatively long, stable postoperative course. In patients presenting with a low KPS score a poor prognosis is demonstrated, and early diagnosis and treatment are recommended to avoid it.

Adult↗
PubMed1990

Position and orientation of the foramen magnum in higher primates.

The location of the foramen magnum, with respect to the longitudinal axis of the cranium, and its orientation with respect to the Frankfurt Horizontal, have been studied in a total of 328 modern human and Pan crania. The samples were chosen in order to examine the effect of overall size difference on foramen magnum disposition. Foramen position (expressed as three indices) and inclination are relatively invariant among the modern human samples, but the foramen magnum is consistently, and statistically significantly, more anteriorly located in Pan paniscus than in Pan troglodytes. Sexual dimorphism is virtually non-existent. There is an apparent allometric effect on foramen position, but not on inclination, so that larger crania in the modern human and Pan paniscus samples tend to have more posteriorly situated foramina. The disposition of the foramen is unrelated to cranial base angle or facial prognathism, except that in Pan paniscus its relative anterior location is linked with the more flexed cranial base in that species. These results provide a comparative context for the examination of differences in foramen magnum disposition in fossil hominids. Differences in foramen magnum position and orientation between KNM-ER 1813 and A. africanus are most unlikely to be due to within-taxon variability.

Animals↗
PubMed1991

Effects of age and gender on the location and orientation of the foramen magnum in rhesus macaques (Macaca mulatta).

Endocasts from 378 rhesus macaque skulls from the Cayo Santiago skeletal collection were measured to determine the effects of age and gender on the position and orientation of the foramen magnum. The foramen magnum migrates from a rostral to a caudal position and its angle changes during postnatal development. The angles and relative positions of the foramen magnum are similar for both genders of infants and for both genders of adults. However, analyses of linear response and plateau (LRP) functions reveal significant differences between males and females in the timing of reorientation of the angle and migration of the foramen magnum. The mean adult angle and relative position of the foramen magnum are reached by 4.7 years in females, but they do not achieve their adult values until 7.1 years in males. A similar pattern is observed for the brainstem region of the basicranium. Mean adult lengths of the brainstem region are reached at 5.2 years in females and 7.1 years in males. The relationships between cranial capacity, the growth pattern of the brainstem, and the pattern of change for the angle and the relative position of the foramen magnum are examined. Quantification of the effects of age and gender on the location of the foramen magnum in a large sample of endocasts from one species of higher primate has potential implications for research on human development, and for interpretation of juvenile specimens in the hominid fossil record.

Age Factors↗
PubMed1988

Variations in the shape of foramen magnum in Indian skulls.

200 skulls from anthropology museum of GSVM Medical College, Kanpur, U.P., India, were studied to note the variations in the shape of foramen magnum. Foramen magnum was found to be variable in shape: Shapes noted were oval (64%), hexagonal (24.5%), pentagonal (7.5%), irregular (3.5%) and round (0.5%). The findings are hitherto not reported.

Foramen Magnum↗
PubMed1999

End-to-end anastomosis of the posterior inferior cerebellar artery before excision of a meningioma involving the lower clivus and the foramen magnum. Case report.

BACKGROUND: Petroclival and foramen magnum meningiomas sometimes encase the vertebrobasilar arterial system. Magnetic resonance imaging can clearly reveal such encasement. The case presented here was of a meningioma involving the lower clivus and the foramen magnum, encasing a lateral segment of the posterior inferior cerebellar artery (PICA), despite the fact that no definitive diagnosis of the encasement of the PICA was made on preoperative radiological examination. End-to-end anastomosis of the PICA was necessary before excision of the tumor. METHODS: A 55-year-old woman presented with complaints of headache and numbness of the right upper extremity. Gadolinium diethylene-thiamine-pentaacetic acid enhanced T1-weighted magnetic resonance (MR) images showed a homogeneously enhanced mass lesion involving the lower clivus and the foramen magnum. Direct surgery was then performed, and the lateral medullary segment of the left PICA was found to be encased by the tumor. End-to-end anastomosis was performed using No. 10-0 interrupted monofilament nylon sutures. Total removal of the tumor was performed after completion of the anastomosis. The patient was free of neurological abnormalities and no recurrence of tumor was found during a 2-year follow-up period. CONCLUSIONS: Revascularization is sometimes thought to be required for resection of craniospinal meningiomas even when they do not appear to encase the vertebro-basilar arterial system on preoperative MR imaging and cerebral angiograms. In the present case, dissection of the PICA from the tumor was attempted, but was difficult due to tight encasement of the PICA by the tumor.

Anastomosis, Surgical↗
PubMed1994

Morphometric analysis of the foramen magnum in Pekingese dogs.

The size and shape of the foramen magnum were studied in skulls from 75 adult and 5 juvenile Pekingese dogs. After maceration of the skulls, the height, width, and area of each foramen magnum were measured, and various skull indices were determined. The shape of the foramen varied from ovoid to rectangular and had a dorsal notch in all but 2 skulls. Prolapse of cerebellum or brain stem through the enlarged opening was prevented by a fibrous membrane covering the dorsal notch. Mean +/- SD area of the foramen was 138.1 +/- 26.1 mm2; its mean total height was 15.0 +/- 2.9 mm, and its mean maximal width was 13.3 +/- 1.1 mm. Statistically, variability in the area of the foramen was mainly correlated with total height of the foramen, including the dorsal notch. Total height of the foramen was not correlated with age or gender. The degree of dysplasia, notch index, and occipital index of each foramen magnum were determined. To allow a more accurate evaluation of the morphology of the foramen, the foramen magnum index, defined as the ratio between the maximal width and the total height of the foramen, was also computed. Mean +/- SD foramen magnum index was 91.8 +/- 17.1 in the adult Pekingese dogs. Foramen magnum index was not significantly correlated with age, but was significantly larger in male than in female dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed2003

Foramen magnum metastatic malignant melanoma.

The foramen magnum as a site for brain metastasis is extremely rare. We report the case of a 24-year-old male who presented with features of increased intracranial pressure and lower cranial nerve palsies. Imaging revealed a foramen magnum tumor with extension up to the cerebellar vermis superiorly and into the spinal canal inferiorly (craniospinal mass) with mild obstructive hydrocephalus. A malignant melanoma was completely excised. The patient continued to be tumor-free 24 months later.

Adult↗
PubMed2001

[Microsurgical treatment of foramen magnum tumors].

OBJECTIVES: To review the radiological features, and results of microsurgical treatment of foramen magnum tumors. METHODS: We retrospectively analyzed the results of microsurgical treatment of 31 patients with foramen magnum tumor. Fifteen patients had pathological schwannomas (neurinomas), 13 patients meningiomas, and 3 patients chordomas. According to tumor extension, MRI findings and microsurgical approaches, the tumors were classified in two types. Type I tumors located at the ventral foramen magnum, including those originated from the posterior fossa with minimal enlargement of the ventral or anterior-lateral (15 patients). Type II tumors located at the posterior or lateral foramen magnum, including those arising from the spinal canal with minimal enlargement of the foramen magnum (16 patients). Surgical approaches to tumors in this series included suboccipital posterior approach (18 patients), extreme lateral or transcondylar approach (10), and suboccipital retrosigmoid approach (3). RESULTS: Total removal was achieved in 25 patients, subtotal removal in 5, and partial removal in 1. No operative death occurred. Type I foramen magnum tumors were totally removed in 9 patients, subtotally removed in 5 and partially removed in 1. All of type II foramen magnum tumors were totally removed. CONCLUSIONS: To totally resect type I foramen magnum tumors, extreme lateral transcondylar approach is an optimal choice. Type II foramen magnum tumors can be totally removed with good prognosis.

Adolescent↗
PubMed1999

Midline and far lateral approaches to foramen magnum lesions.

Twenty patients with foramen magnum lesions were operated upon in the last 5 years at Postgraduate Institute of Medical Education and Research, Chandigarh. The common presenting features were quadriparesis, quadriplegia, diminished sensations, neck pain and respiratory insufficiency. The lesions encountered were meningiomas, neurofibromas, posterior inferior cerebellar artery aneurysms, neurenteric cyst and chordoma. Patients with posterior or posterolaterally placed lesions were operated by the midline posterior approach while those with anterior or anterolateral lesions were managed by the far lateral approach. All mass lesions were excised completely and the aneurysms were clipped. Seventeen patients made good neurological recovery while three died. The latter three patients presented very late. The merits of various surgical approaches to the foramen magnum are discussed.

Adolescent↗
PubMed1990

Surgical approaches to foramen magnum meningioma--report of three cases.

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.

Adult↗
PubMed1997

Morphometric analysis of the foramen magnum in German shepherd dogs (Alsatians).

In this study, a total of 32 skulls from German Shepherd (Alsatian) puppies were used. These animals were divided into two groups and examined individually. Group 1 included the puppies of between 43-60 days old. Group 2 included the puppies of between 61-107 days old. We based our study on the changes in shape and size of the foramen magnum and the correlation of normal craniometric measurements in the German Shepherd puppies. In group 1, a maximum width of the foramen magnum of 15.55 mm, a height of the foramen magnum of 14.38 mm and a foramen magnum index of 92.67 were observed. In group 2, a maximum width of the foramen magnum of 17.49 mm, a height of the foramen magnum of 16.34 mm and a foramen magnum index of 93.51 were measured. A high positive correlation was found between the maximum width and height of the foramen magnum, the maximum width of the occipital condyles, the maximum width of the bases of the jugular processes, the skull height, the height of the occipital triangle, the skull length from prosthion to basion and the skull length from prosthion to the caudal borders of the occipital condyles. A negative correlation was observed between the width and height of the foramen magnum and indices. Although there was no relation between the foramen magnum index and the age of the animals, an important difference was found between groups 1 and 2. A negative correlation was observed between the foramen magnum index and the rate of increase in the cranial volume. In all the animals examined, the dorsal bone of the foramen magnum was closed, therefore any extension or dorsal notch was not seen. Such an extension or dorsal notch of the foramen magnum in the German Shepherd puppies may therefore be the result of a pathological condition.

Aging↗
PubMed2003

Foramen magnum meningiomas: concepts, classifications, and nuances.

Foramen magnum meningiomas represent a common histological tumor in a rare and eloquent location. The authors review the clinical presentation, relevant anatomical details of the foramen magnum region, neuroimaging features, the posterior and posterolateral surgical approaches for resection, and outcomes. Based the experiences of the senior author (M.D.C.) and a review of the literature, they introduce the concept of a "surgical corridor," discuss the classification of these tumors, and the nuances of care for patients with these challenging lesions.

Foramen Magnum↗
PubMed2002

Syringomyelia associated with foramen magnum arachnoiditis.

OBJECT: Syringomyelia is often linked to pathological lesions of the foramen magnum. The most common cause is hindbrain herniation, usually referred to as Chiari I or II malformation. Foramen magnum arachnoiditis without either Chiari I or II malformation is a rare cause of syringomyelia. The authors undertook a retrospective analysis of 21 patients with foramen magnum arachnoiditis (FMA) and syringomyelia treated between 1978 and 2000 to determine clinical course and optimum management. METHODS: In the review of records, 21 patients with FMA and syringomyelia were documented. A stable clinical course was demonstrated in three patients in whom surgery was not performed, and one patient refused surgical intervention. Seventeen patients underwent 23 operations to treat progressive neurological disease. Of these 23 operations, 18 involved opening of the foramen magnum, arachnoid dissection, and placement of a large dural graft. One patient underwent insertion of a ventriculoperitoneal shunt for treatment of accompanying hydrocephalus, one patient received a cystoperitoneal shunt for an accompanying arachnoid cyst; two syringoperitoneal and one syringosubarachnoid shunts were also inserted. Hospital and outpatient files, neuroimaging studies, and intraoperative photographic and video material were analyzed. Additional follow-up information was obtained by telephone interview and questionnaires. Standard and cardiac-gated magnetic resonance imaging studies are the diagnostic procedures of choice in these patients. Sensory disturbances, dysesthesias, and pain were the only symptoms likely to improve after foramen magnum surgery. Motor weakness and gait disturbances, which were severe in a considerable number of patients, and swallowing disorders tended to remain unchanged. As a consequence of the rather severe arachnoid lesions in most patients, clinical recurrences were observed in 57% over a 5-year period. CONCLUSIONS: Surgery for FMA and syringomyelia has to provide clear cerebrospinal fluid pathways between the cerebellopontine cisterns, spinal canal, and fourth ventricle. If this can be achieved successfully, the syrinx decreases in size and the clinical course of the patient may even improve. In patients with severe and widespread areas of arachnoiditis, however, multiple operations may be required at least to stabilize the clinical course.

Adult↗