Meningiomas of the basal posterior fossa. Surgical experience in 80 cases.
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INTRODUCTION: Despite recent improvements in microsurgical and radiotherapy techniques, treatment of basal posterior fossa meningiomas still carries an elevated risk of morbidity. We present our results in a series of patients with this type of tumor and review the recent literature looking for the results obtained with different approaches and the new tendencies and algorithms proposed for managing these challenging lesions. MATERIAL AND METHODS: We analyzed retrospectively the clinical presentation and outcome of 80 patients consecutively operated between 1979 and 2003 for basal posterior fossa meningioma (foramen magnum tumors excluded). All patients had preoperative CT scans and the majority MRI studies. A total of 114 operations were performed including two-stage operations, reoperation for recurrence, CSF diversion, and XII-VII anastomosis. The most commonly used approaches were lateral suboccipital retrosigmoid, subtemporal-transtentorial, frontotemporal pterional and supra-infratentorial presigmoid. Thirteen patients received postoperative radiotherapy. RESULTS: There were 59 (73.7%) women and 21 men (mean age = 51.5 years; range = 18-78 yrs). Most common presenting symptoms were cranial nerve dysfunction, gait disturbances and intracranial hypertension. The mean duration of symptoms was 2.9 years. 70% of the tumors were over 3 cm in size. Fifty patients (62.5%) had a complete resection, 22 (27.5%) subtotal resection (> 90% tumor volume removed), and 8 (10%) only partial resection. Postoperative complications included hematoma, CSF leak, and infection. Fifty four (67.5%) patients developed new or increased cranial nerve deficits and 12.5% somatomotor, somatosensory or cerebellar deficits immediately after surgery with subsequent improvement in most cases. Following initial surgery 67 patients made a good recovery, 10 developed variable degrees of disability and 3 died. Eleven patients died later in the course for tumor recurrence with or without reoperation, malignant meningioma or unrelated causes. There were 9 recurrences in the subgroup of patients having complete resection initially (mean follow-up = 8.6 years). The majority of patients having initial subtotal or partial resections have been managed without reoperation during a mean follow-up period of 6.5 years (radiosurgery and/or observation). DISCUSSION AND CONCLUSION: Current microsurgical and radiotherapy techniques allow either a cure or an acceptable control of basal posterior fossa meningiomas. In patients with tumor invasion of the cavernous sinus, extracranial extension, violation of the arachnoidal membranes in front of the brainstem, or encasement and infiltration of major arteries, a subtotal excision seems preferable followed by observation and/ or radiosurgical treatment. Apart from the patients age and the clinical presentation (symptomatic or not), the size and secondary extensions of the tumor must be taken into account for planning treatment in the individual patient. (+info)
Evaluation of platybasia with MR imaging.
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BACKGROUND AND PURPOSE: Platybasia, or abnormal obtuseness of the basal angle, was first measured on plain skull images. At present, evaluation of the brain and skull more commonly involves CT and MR imaging. We evaluated a new MR imaging method of evaluating platybasia. METHODS: We retrospectively evaluated midline sagittal MR images in 200 adults and 50 children. The basal angle of the skull base was measured by using two methods: The standard MR imaging technique measured the angle formed by two lines-one joining the nasion and the center of the pituitary fossa connected by a line joining the anterior border of the foramen magnum and center of the pituitary fossa. The modified technique measured the angle formed by a line across the anterior cranial fossa and dorsum sellae connecting a line along the clivus. RESULTS: With the standard MR imaging technique, we obtained mean angles of 129 degrees +/- 6 degrees for adults and 127 degrees +/- 5 degrees for children, compared with 135.3 degrees (composite mean) in previous series. The modified technique produced values of 117 degrees +/- 6 degrees for adults and 114 degrees +/- 5 degrees for children, which were significantly lower that those of standard MR imaging and traditional radiography (P <.05). CONCLUSION: Both the standard and modified MR imaging techniques produced basal angles lower than those previously reported with standard radiography. The modified technique uses clearly featured landmarks that can be reproduced consistently on midline sagittal T1 images. This technique and its corresponding values can be used as the new standard for evaluating the basal angle. (+info)
Reduction of blood flow in the brain stem and cerebellum caused by petroclival tumors.
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Blood flow in the brain stem (BSBF) and cerebellum (CerBF) was investigated by positron emission tomography in 12 patients with petroclival tumors (study group) and 14 healthy volunteers (control group). (15)O-labeled water was used as the radioisotope tracer. BSBF and ipsilateral CerBF were significantly lower in the study group compared with the control group (p < 0.005). Five of 12 patients in the study group exhibited more than 20% reduction of CerBF ipsilateral to the tumor, whereas no such asymmetry was disclosed in any subject in the control group (p < 0.01). Sex, age, and tumor histology had no statistically significant association with the level of BSBF. Ipsilateral CerBF was significantly lower in patients with vestibular schwannomas, compared to those with sphenopetroclival meningiomas (p < 0.025). No statistically significant association between BSBF and the type of postoperative course was found, whereas four of the five patients with more than 20% reduction of CerBF ipsilateral to the tumor had prominently increased cerebellar ataxia after removal of the neoplasm. Preoperative investigation of the cerebral blood flow may be important for the prediction of outcome after surgical resection of petroclival tumors. (+info)
Traumatic posterior fossa hematomas.
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PURPOSE: Posterior fossa epidural hematomas are much less common than supratentorial epidural hematomas. The incidence of posterior fossa epidural hematomas among intracranial epidural hematomas has been reported to be 4% to 7%. Seven cases of posttraumatic posterior fossa epidural hematomas diagnosed by computed tomography (CT) are reported with radiological and clinical findings. MATERIALS AND METHODS: This study consisted of 7 posterior fossa epidural hematoma cases, out of 585 severe head trauma patients admitted and hospitalized in an 18-month period. The patients were evaluated regarding age, gender, type of trauma, cranial CT and Glasgow coma score in admittance, treatment and follow-up. RESULTS: Average age was 24.2 years and 85.7% of the cases were male. All cases had occipital fracture. Fifty-seven percent of the cases had only occipital fracture and posterior fossa epidural hematoma. All of the cases in this group were neurologically intact except for one who had a Glasgow coma score of 9 in admission. Two cases of this group were conservatively treated. In the others posterior fossa epidural hematomas got larger and they were treated surgically; these two cases recovered after surgery. Three of the 7 cases had the supratentorial region lesions; one of these cases died before operation. Two of them were treated surgically, one of them died and the other showed recovery after surgery. CONCLUSION: Acute posterior fossa epidural hematomas are usually symptom-free initially. After this silent period, clinical deterioration is quick to become fatal in most of patients. Surgery can be life-saving when performed in a timely manner. Therefore, CT should always be performed when an occipital trauma is diagnosed. (+info)
Giant pituitary adenoma invading the clivus.
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A 26-year-old man was admitted with complaints of worsening of vision for one month. Investigations revealed a large sellar and parasellar tumor mass invading into both the cavernous sinuses. The tumor invaded the clivus and both petrous apices. It was radically but partially resected through a transsphenoidal approach. Following surgery, the patient showed symptomatic improvement. The residual tumor was treated by radiation treatment. The case is discussed and the literature on the subject is briefly reviewed. (+info)
Surgical management of tuberculum sellae meningiomas: involvement of the optic canal and visual outcome.
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OBJECTIVE: To present a large series of surgically treated tuberculum sellae meningiomas with particular regard to involvement of the optic canal and visual outcome. METHODS: A retrospective analysis was done on 53 patients (40 female) with meningiomas originating from the tuberculum sellae who underwent surgery between 1991 and 2002. The standard surgical approach consisted of pterional craniotomy. Sixteen meningiomas extended posteriorly onto the diaphragma sella, 29 anteriorly to the planum sphenoidale, and 19 to the anterior clinoid process. Thirty seven tumours involved the optic canal, three bilaterally. Follow up ranged from 6 to 108 months (mean 29.9 months). RESULTS: Total macroscopic resection was achieved in 48 patients. Median tumour size was 2.6 cm. Postoperatively, visual acuity improved in 20 patients and deteriorated in seven. Preoperative and postoperative visual acuity worsened with increasing duration of preoperative symptoms and with increasing age. Extension into the intraconal space was a negative predictor. However, tumour size did not influence visual acuity. Recurrence occurred in two cases (21 and 69 months postoperatively). Two patients died from causes unrelated to the tumour. CONCLUSIONS: In the majority of patients with tuberculum sellae meningiomas, total resection may be achieved through a pterional approach with minimal complications. (+info)
MR imaging of orbital inflammatory pseudotumors with extraorbital extension.
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OBJECTIVE: To demonstrate a variety of MR imaging findings of orbital inflammatory pseudotumors with extraorbital extension. MATERIALS AND METHODS: We retrospectively reviewed the MR features of five patients, who were diagnosed clinically and radiologically as having an orbital inflammatory pseudotumor with extraorbital extension. RESULTS: The types of orbital pseudotumors were a mass in the orbital apex (n = 3), diffuse form (n = 2), and myositis (n = 1). The extraorbital extension of the orbital pseudotumor passed through the superior orbital fissure in all cases, through the inferior orbital fissure in two cases, and through the optic canal in one case. The orbital lesions extended into the following areas: the cavernous sinus (n = 4), the middle cranial fossa (n = 4), Meckel's cave (n = 2), the petrous apex (n = 2), the clivus (n = 2), the pterygopalatine fossa and infratemporal fossa (n = 2), the foramen rotundum (n = 1), the paranasal sinus (n = 1), and the infraorbital foramen (n = 1). On MR imaging, the lesions appeared as an isosignal intensity with gray matter on the T1-weighted images, as a low signal intensity on the T2-weighted images and showed a marked enhancement on the post-gadoliniumdiethylene triamine pentaacetic acid (post-Gd-DTPA) T1-sequences. The symptoms of all of the patients improved when they were given high doses of steroids. Three of the five patients experienced a recurrence. CONCLUSION: MR imaging is useful for demonstrating the presence of a variety of extraorbital extensions of orbital inflammatory pseudotumors. (+info)
Rapid disappearance of acute posterior fossa epidural hematoma.
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A 34-year-old man presented with an acute epidural hematoma that resolved within 24 hours after a fall. On admission, neurological examination found no abnormalities. Computed tomography (CT) indicated a linear fracture in the occiput. Four hours after the injury, the patient's condition worsened and repeat CT showed a bilateral epidural hematoma in the posterior fossa extending over the bilateral transverse sinuses and severe brain swelling. The patient's family refused surgery. Conservative management with pentothal was performed in the intensive care unit. Follow-up CT 21 hours after the initial injury showed complete resolution of the hematoma and an increase in the CT density of the pericranial soft tissue near the hematoma. The pressure gradient between the subgaleal and epidural space may have been important in the rapid disappearance of this epidural hematoma. (+info)