Posterior fossa epithelial cyst: case report and review of the literature. (1/83)

A 49-year old woman with progressive cranial nerve signs and hemiparesis was found at MR imaging and at surgery to have a cyst at the foramen magnum. Immunohistochemistry and electron microscopy showed an epithelial cyst of endodermal origin. MR findings were of an extraaxial mass, with short T1 and T2 times. Unless immunohistochemistry and electron microscopy are used in the final diagnosis of such cysts, all posterior fossa cysts lined by a single layer of epithelium should be described simply as epithelial cysts.  (+info)

Extreme lateral transcondylar approach to the skull base. (2/83)

In this study, the authors present their experience of using extreme later transcondylar approach (ELTC) for treating 7 patients with lesions in the anterolateral foramen magnum, upper cervical spine and cerebellopontine angle reaching upto jugular foramen. The tumours included meningiomas, neurofibromas (2 cases each), chondrosarcoma, epidermoid and aneurysmal bone cyst (one case each). The approach was used alone, in combination with retrolabyrinthine presigmoid approach in a patient with lower cranial nerve neurofibroma extending extracranially through the jugular foramen, or in combination with partial C1-C3 laminectomy in two patients with meningiomas situated anterolateral to the cord from the foramen magnum to C3. In two patients with extradural vertebral artery (VA) entrapment by a chondrosarcoma and aneurysmal bone cyst respectively, the vertebral artery was ligated distal to the tumour. The tumours were totally excised in five cases and partially in two. There was no preoperative mortality. The major complications included cerebrospinal fluid leak from the wound (3 cases) and increase in lower cranial nerve paresis (2 cases). At follow up, ranging from 6 months to 2 years, 5 patients showed no tumour recurrence. There was improvement in neurological status. One patient, with a partially excised aneurysmal bone cyst, showed no added deficits or increase in the tumour size. However, there was a massive regrowth in the patient with chondrosarcoma after 6 months. This technique provided a wide surgical exposure with direct visualization of the tumour-anterior cord interface, early proximal control of the VA and preservation of lower cranial nerves.  (+info)

Choroid plexus papilloma of cerebellopontine angle with extension to foramen magnum. (3/83)

A case of choroid plexus papilloma resembling meningioma of cerebellopontine (CP) angle with its extension to foramen magnum is presented. Occurrence of this tumour in CP angle is very rare. Its extension towards foramen magnum is further rare. It was a real diagnostic enigma preoperatively as the tumour was resembling meningioma upto some extent on radiological study. Retromastoid craniectomy with microsurgical excision of tumour and its extension was achieved in toto. Tumour was attached to few rootlets of lower cranial nerves which were preserved. Attachment of the tumour with lower cranial nerves again caused diagnostic confusion with neurofibroma intraoperatively.  (+info)

Avulsion fracture of the anterior half of the foramen magnum involving the bilateral occipital condyles and the inferior clivus--case report. (4/83)

A 38-year-old male presented with an avulsion fracture of the anterior half of the foramen magnum due to a traffic accident. He had palsy of the bilateral VI, left IX, and left X cranial nerves, weakness of his left upper extremity, and crossed sensory loss. He was treated conservatively and placed in a halo brace for 16 weeks. After immobilization, swallowing, hoarseness, and left upper extremity weakness improved. Hyperextension with a rotatory component probably resulted in strain in the tectorial membrane and alar ligaments, resulting in avulsion fracture at the sites of attachment, the bilateral occipital condyles and the inferior portion of the clivus. Conservative treatment is probably optimum even for this unusual and severe type of occipital condyle fracture.  (+info)

Cystic lesion at the foramen magnum disseminated from a pituitary adenoma--case report. (5/83)

A 38-year-old male presented with a cystic lesion at the foramen magnum due to intracranial dissemination from a pituitary adenoma. The primary tumor had required reoperation for regrowth twice. The tumor at the foramen magnum was removed surgically. Two smaller solid tumors were located in the left parietal convexity and the right temporal lobe. The former tumor was also removed surgically and the latter was observed. Histological examination showed the typical characteristics of pituitary adenoma in both surgical specimens. Immunohistochemical staining with MIB-1 and p53 antibodies showed low (< 1%) and negative reaction. Patients with pituitary adenoma, even benign tumors, must be carefully followed up for signs of metastasis.  (+info)

Midline and far lateral approaches to foramen magnum lesions. (6/83)

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.  (+info)

Far lateral approach for foramen magnum lesions. (7/83)

Twelve patients with lesions in the anterior or anterolateral regions of foramen magnum were treated through the far lateral approach. The patients presented with neck pain, dysesthesia, quadriparesis, numbness, respiratory distress, and spastic contractures. Most lesions were meningiomas and neurofibromas, with one patient each with a posterior inferior cerebellar artery aneurysm, neurenteric cyst, and chordoma. All mass lesions were excised totally and the aneurysm was clipped. Three patients had severe respiratory problems preoperatively and two of them died. The other patients made a satisfactory neurological recovery. It was not found necessary to resect the condyle or mobilize the vertebral artery in any of the patients.  (+info)

Location of the glenoid fossa after a period of unilateral masticatory function in young rabbits. (8/83)

Changes in glenoid fossa position and skull morphology after a period of unilateral masticatory function were studied. The right-side maxillary and mandibular molars in twenty-seven 10-day-old rabbits were ground down under general anaesthesia. The procedure was repeated twice a week, until the rabbits were 50 days old. Fourteen rabbits were then killed and 13 left to grow to age 100 days. Nine 50-day-old and sixteen 100-day-old rabbits with unmodified occlusions served as controls. Three-dimensional measurements were made using a machine-vision technique and a video-imaging camera. The glenoid fossa position become more anterior in both groups of animals subjected to molar grinding as compared with controls (P < 0.01 in the 50-day-old group and P < 0.05 in 100-day-old group). In the 100-day-old group the right-side fossa was also in a more inferior position (P < 0.01). The glenoid fossa was more anteriorly located on the right than on the left side of individual animals in the group in which the right-side molars had been ground down (P < 0.001).  (+info)