Management-related morbidity in unselected aneurysms of the upper basilar artery.

A series of 49 consecutively treated patients with 52 aneurysms of the upper basilar artery (BA) is presented. Thirty-nine aneurysms arose at the BA bifurcation, 11 at the origin of the superior cerebellar artery (SCA), and two from the upper BA trunk just below the SCA. The patient population consisted of 36 women and 13 men, with a mean age of 50 years (range 23-74 years). Of the 35 patients presenting with subarachnoid hemorrhage, 10 were Grade I, 10 were Grade II, 11 were Grade III, and four were Grade IV according to the Hunt and Hess scale. Treatment consisted of aneurysm neck clipping in 28, proximal occlusion of the BA in three, and endovascular therapy with coils in four patients. The remaining 14 patients with unruptured aneurysms underwent direct neck clipping. Postoperatively, 38 patients developed diplopia in at least one direction of gaze but this had resolved in 31 of them at the last follow-up evaluation. There were four deaths (8.2%): two as a result of rebleeding following coil compaction at 8 days and 9 months posttreatment, respectively; one as a result of vasospasm; and one as a result of brainstem infarction after proximal occlusion of the BA in a giant bifurcation aneurysm. Of the surviving patients, 33 (67.3%) made an excellent recovery, seven (14.3%) made a good recovery, and five (10.2%) were in poor condition at the last follow-up review. Direct microsurgical clipping of most aneurysms of the BA apex region can be performed with acceptable rates of morbidity. These data from an unselected series of patients in a general hospital provide a basis for comparison with developing alternative techniques.

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 tumor's 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.

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.

Temporary vessel occlusion and barbiturate protection in cerebral aneurysm surgery.

In a review of 147 patients with intracranial aneurysms surgically treated by one surgeon (FAD) between 1980 and 1987, 36 selected patients received intraoperative barbiturate protection with sodium thiopental during temporary arterial occlusion. Thiopental doses of 5 to 15 mg/kg were used. Twenty-nine of 36 (81%) had ruptured aneurysms. Occlusion times ranged from 3 to 93 minutes, with a mean of 16.2 minutes. Seven patients had new neurological deficit in the immediate postoperative period, but in only two did these persist. Twenty-one patients (72%) with subarachnoid hemorrhage and 6 with incidental aneurysms made a good recovery. Of the 9 patients with significant permanent deficit, all but 2 were related to either the severity of the initial hemorrhage or to delayed vasospasm. In only one instance might temporary arterial occlusion have led to permanent neurological sequelae. Temporary arterial occlusion with barbiturate protection is a safe technique. For aneurysms that are more surgically complex, it allows for complete dissection of the aneurysm neck and identification and preservation of the surrounding vascular anatomy, while reducing the risk of intraoperative rupture and postoperative stroke.

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.

The Tolosa-Hunt syndrome: computed tomographic changes and reversal after steroid therapy.

Painful ophthalmoplegia, or Tolosa-Hunt syndrome, is due to nonspecific inflammation of the cavernous sinus. We report two cases of the Tolosa-Hunt syndrome, which, on high resolution fourth-generation CT scan, showed an abnormality in the cavernous sinus consisting of an enhancing soft tissue mass. Both the clinical findings and the CT lesion resolved after high-dosage corticosteroid therapy.

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.

The role of the prostacyclin-thromboxane system in cerebral vasospasm following induced subarachnoid hemorrhage in the rabbit.

Subarachnoid hemorrhage (SAH) was induced in 50 rabbits by injecting 1.25 cc/kg of autologous, well heparinized, fresh arterial blood into the cisterna magna, followed by suspending the animals in a head-down position at 30 degrees for 15 minutes. The animals were evenly divided into five groups: a control group, or groups receiving post-SAH prostacyclin (PGI2), carbacyclin, thromboxane A2 (TXA2) synthetase inhibitor (OKY-1581), or nutralipid. Radiographic vertebrobasilar arterial spasm was demonstrated on the 3rd day post-SAH in the control animals. This was decreased in the prostacyclin and the carbacyclin groups and was absent in the OKY-1581 and the nutralipid groups. Cerebral blood flow (CBF) measurements on the 4th day post-SAH using the xenon-133 technique failed to reveal any significant difference between the prostacyclin, the carbacyclin, and the control groups, but flows in the nutralipid and the OKY-1581 groups were significantly higher. There was a good correlation between the clinical status and the CBF. Intracytoplasmic vacuolation and detachment of the vascular endothelium, seen ultrastructurally, may account for the impaired synthesis of prostacyclin. Exogenous prostacyclin and carbacyclin decreased vasospasm but failed to improve cerebral perfusion. OKY-1581 blocked the synthesis of the potent vasoconstrictor, TXA2, which is not only formed during platelet aggregation but also induces platelet aggregation. Nutralipid contains linolenic acid, a precursor of eicosapentaenoic acid (EPA), which is more potent in inhibiting platelet aggregation and in blocking TXA2 production. The various fatty acid constituents of nutralipid bind to albumin and thereby shorten the half-life of TXA2.

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.

Dandy-Walker syndrome: analysis of 21 cases.

During the years 1950 to 1978, a total of 21 cases of Dandy-Walker syndrome were seen at the Vancouver General Hospital. Apart from hydrocephalus, the associated brain anomalies included agenesis of the corpus callosum in four cases, occipital meningocele in two and aqueductal stenosis in one patient. Systemic malformations were present in four patients and included two cases of cleft palate, one of polycystic kidneys and one of congenital rubella syndrome. The over-all mortality was 48 per cent, but has declined since 1965. Of the 12 cases treated surgically, only four have died. The number of shunt revisions was high (about two per patient). Of the 11 survivors, three have normal intelligence, four show mild mental retardation, and four are moderately to severely retarded. The differential diagnosis, clinical course and surgical therapy are discussed. It is recommended that double shunting of a lateral ventricle and of the enlarged fourth ventricle should be the primary procedure in cases associated with aqueductal stenosis or occlusion, and should be the secondary procedure in patients who exhibit recurrence of increased pressure in the posterior fossa after simple shunting of a lateral ventricle.