Felix A. Durity

Combined Frontotemporal-Orbitozygomatic Approach for Tumors of the Sphenoid Wing and Orbit

An extension of a combined frontotemporal and orbitozygomatic exposure was developed to remove 8 hyperostosing invasive sphenoid wing meningiomas (Group 1) and 11 complicated intraorbital tumors with and without intracranial extension (Group 2). Two separate bone flaps were created: a free frontotemporal-sphenoidal (pterional) bone flap and en bloc removal of the superior and lateral orbital margins with attached zygomatic arch. Cranio-orbital reconstruction was performed using the inner table of the pterional bone flap. Complete tumor removal was achieved in 14 patients and near total removal in 5. There was no mortality and in those patients who did not require orbital exenteration excellent to good cosmetic results were achieved in all but one case. This approach affords a wide exposure of the orbit and anterior and middle skull base, so that large tumors of the orbit and tumors involving the orbital apex, sphenoid wing, and infratemporal and pterygopalatine fossae can be removed.

p53 and MIB-1 immunohistochemistry as predictors of the clinical behavior of nonfunctioning pituitary adenomas

BACKGROUND P53 expression and increased MIB-1 proliferation index have been shown to correlate with invasive behavior in pituitary adenomas. The purpose of this study was to determine whether these indices could be used to predict a higher likelihood of recurrence in clinically nonfunctional pituitary adenomas and thus guide adjuvant therapy. METHODS Fifty-one clinically nonfunctional pituitary adenomas were selected from the database at the Vancouver Hospital and Health Sciences Center between the years 1990-1998. Included were 32 nonrecurrent and 19 recurrent adenomas. RESULTS The mean initial labelling index for p53 in nonrecurrent tumours was 0.38% (0-1.58%), while it was 0.46% (0-3.65%) for recurrent adenomas. The mean initial MIB-1 index for nonrecurrent tumours was 1.63% (0.08-9.36%), while for recurrent tumours it was 1.92% (0-7.76%). The percentage of p53 positive adenomas was 66% for nonrecurrent tumours and 68% for recurrent tumours. None of the differences in the labelling indices between the recurrent and nonrecurrent groups was statistically significant. As 12 patients (38%) in the nonrecurrent group had undergone radiotherapy as initial adjuvant therapy after surgery and none of the recurrent group had done so, patients who did not receive radiotherapy in the nonrecurrent group were analyzed separately. Again, none of the differences in the labelling indices between the recurrent and nonrecurrent groups was statistically significant when the effect of radiotherapy was removed from the analysis. CONCLUSIONS The results demonstrate no statistical difference in the p53 or MIB-1 labelling indices between recurrent and nonrecurrent nonfunctional pituitary adenomas. Concern should be raised in attaching too much clinical significance to these labelling indices, especially with respect to p53 as a predictor of the clinical behavior of nonfunctional pituitary adenomas.

Middle fossa arachnoid cyst and subdural hematoma: CT studies.

A patient with a history of previous head injury presented with an isodense subdural hematoma with extension into a preexisting middle fossa arachnoid cyst. The latter, suspected on the basis of findings pointing to chronic expansion of the middle fossa, was confirmed in a repeat CT study carried out after evacuation of the hematoma.

Computed tomography of anterior inferior cerebellar artery aneurysm mimicking an acoustic neuroma.

Twenty-one previously reported cases of aneurysms of the anterior inferior cerebellar artery (AICA) were reviewed. They often present acutely with subarachnoid hemorrhage due to rupture, or less frequently with an insidious onset, as a cerebellopontine angle (CPA) mass. Rupture of the aneurysm is usually not difficult to diagnose because of the acute symptoms and the subarachnoid hemorrhage, which can easily be detected by CT or lumbar puncture. However, caution must be exercised in those lesions presenting as a CPA mass clinically, which on CT appear unusually dense with contrast enhancement. Erosion of the internal auditory canal may be present but is non-specific. If an enhancing CPA mass appears atypical and dynamic CT confirms rapid enhancement, vertebrobasilar angiography is essential to establish an AICA aneurysm as the cause.

Computed tomography of a cerebellopontine angle lipoma.

In this report we document the clinical, radiologic, surgical, and pathologic features of a cerebellopontine angle (CPA) lipoma, including the CT visualization of the seventh and eighth cranial nerves passing through the middle of the lesion, a feature previously undescribed. Comparison is made with other reported CPA lipomas.

Subperiosteal, subperiorbital dissection and division of the anterior and posterior ethmoid arteries for meningiomas of the cribriform plate and planum sphenoidale : technical note

Removal of meningiomas from the region of the cribriform plate and the planum sphenoidale may entail a bifrontal craniotomy and an interruption of the tumors blood supply along the floor of the anterior cranial base. However, with this approach, the presence of bulky tumor above makes it difficult to control bleeding from multiple bony foramina in the anterior cranial base and to expose these foramina. The blood supply to the dura in this region, and, therefore, to these tumors, is predominantly from the anterior and posterior ethmoid arteries. Preoperative embolization of ethmoid arteries is not without a significant and prohibitive risk of blindness. A frontoethmoidal approach to the arteries on both sides requires two separate skin incisions. Therefore, a subperiosteal, subperiorbital dissection and division of these arteries via a bicoronal skin incision is a practical alternative.

Primary choroid plexus papilloma of the cerebellopontine angle.

A case of choroid plexus papilloma of the cerebellopontine angle, extending from the upper cervical region to the level of the tentorial notch, in a 50-year-old woman is presented. The differential diagnosis of tumors in the cerebellopontine angle and the role of surgical treatment vs. radiation therapy are discussed.

Seizure as a Manifestation of Intracranial Hypotension in a Shunted Patient

The authors describe a child with a ventriculo-peritoneal shunt in place for 5 years who presented with ‘postural’ seizures (seizures on sitting upright, which resolved on recumbency). On shunt tap, the cerebrospinal fluid was obtained freely, but required gentle aspiration with a syringe in the recumbent position, suggesting very low intracranial pressure. Contrast magnetic resonance imaging showed pachymeningeal enhancement and enlargement of the pituitary gland diagnostic of intracranial hypotension along with well-decompressed ventricles. At the time of revision of the shunt, no evidence of malfunction was found and the valve was changed to one with a higher opening pressure. Following this, she became asymptomatic and seizure free. This case illustrates the fact that following shunting, intracranial hypotension may also predispose to seizures, and should be kept in mind while managing these patients.

Clinical - radiological correlates in intracerebral hematomas due to aneurysmal rupture.

In this series of intracerebral hematomas from aneurysmal rupture, gathered from several neurosurgical services, certain morphological features were studied in detail. Patients with very large hematomas tended to have poor neurological grades on admission to hospital and their immediate discharge outlook was correspondingly poor. Ruptured middle cerebral and pericallosal artery aneurysms were relatively common causes of intracerebral hematomas. Patients with temporal lobe hematoma did relatively well; those with parietal hematoma did poorly. The larger the hematoma the less chance there was of developing cerebral vasospasm but the more likely was pre-operative brain herniation. The survival was more closely linked to size and location of the hematoma than to the location of aneurysm or the degree of midline shift.

Gyriform Differentiation in Medulloblastoma – A Radiological Predictor of Histology

Medulloblastoma with extensive nodularity (MBEN) is a variant with an apparently favorable outcome. The authors describe a 2-month-old child with MBEN who had a characteristic gyriform morphology on MR imaging preoperatively and was found to have local metastasis into the adjoining cerebellum on histopathological examination. This case illustrates that histological subtyping may be possible based on the imaging morphology in selected tumors, which may have a bearing on the management of these tumors.