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.

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.

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.

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.

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.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 2: Brain morphology.

The authors studied the morphological sequelae of 15 minutes of cerebral oligemia (20 torr cerebral perfusion pressure) and complete cerebral ischemia produced by raised intracranial pressure in rabbits. Ischemic cell change was present in five of seven ischemic animals; it was most extensive in the striatum and hippocampus, with only a few ischemic nerve cells in the thalamus and neocortex. The brains of control and oligemic animals were normal. These results indicate the following: 1) ischemia is a more severe insult than oligemia; 2) compression ischemia results in a pattern of damage that differs from that produced by other types of ischemia; and 3) the method used to reduce cerebral perfusion pressure is an important factor in determining the pattern and extent of brain damage produced.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 1: Pathophysiology, electroencephalography, cerebral blood flow, blood-brain barrier, and neurological function.

Cerebral blood flow, electrical activity, and neurological function were studied in rabbits subjected to either 15 minutes of oligemia (20 torr cerebral perfusion pressure) or complete cerebral ischemia produced by cisterna magna infusion. During oligemia, flow was reduced from 68.4 +/- 4.2 ml/100 gm/min to 26.3 +/- 4.4 (p less than .01), and during ischemia animals had no proven flow. By 5 minutes after oligemia or ischemia significant symmetrical hyperemia occurred and there was no evidence of the no-reflow phenomenon. The electroencephalogram became isoelectric significantly later and returned significantly sooner in oligemia than in ischemia. Oligemic animals had earlier and better return of neurological function than their ischemic counterparts, although postinsult hypocapnia improved functional recovery in both groups. These experiments do not support the concept that oligemia is a more severe insult than complete ischemia. In intracranial hypertension produced by this model, the no-reflow phenomenon does not occur.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 3: Brain energy metabolism.

The authors studied the effect on cortical metabolites of intracranial hypertension produced by the infusion of mock cerebrospinal fluid into the cisterna magna in rabbits subjected to 15 minutes of cerebral oligemia (20 torr) or 15 minutes of complete ischemia. In both groups high-energy metabolites were exhausted within the first 5 minutes of the 15-minute insult. Significant recovery of the high-energy intermediates occurred within 15 minutes of reperfusion, well before return of electroencephalogram (EEG) activity. Continued reperfusion, during which electrical activity and function were returning, brought only moderate improvement in energy metabolites. In contrast, severe lactic acidosis persisted at least 15 minutes after insult, but was reduced by the time EEG activity returned. At no time were there striking differences in metabolites between the oligemic and ischemic groups. These results indicate that recovery in general, and the significantly earlier recovery of oligemic as compared to ischemic animals, cannot be explained on the basis of energy supply. Whether the persistence of lactic acidosis is an important factor limiting return of function requires further study.

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.

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.

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.

Education and information needs identified by patients and key family members prior to surgery for a skull base neoplasm: implications for practice.

Many patients with extensive skull base neoplasms poorly understand the nature of their problems. Therefore, education of patients and family members is an important component of care. Research has established the benefits of pre-operative education for other types of surgery and information seeking as an important method of coping. Yet in 184 references on skull base surgery (1996-1999), no case-based or research data that examined education and information needs prior to hospitalization for surgery was found. The investigators present findings from Phase 1 of a descriptive research study designed to determine the education and information needs perceived by patients and family members at their initial visit to the neurosurgeon and on admission to hospital. Data was collected, using interviews and a questionnaire, from 18 patients with skull base neoplasms and 15 key family members. The study findings provide insight into the experience of patients and families during a time period (prehospitalization) that has not been explored. Results indicate that key education needs of participants are related to the brain tumour and surgery. Findings reveal patient participants in contrast to family members had little in the way of information needs. Underlying and impacting the education and information needs is the theme of 'Hearing the News'. Relevance of the results to nursing practice in the pre-operative phase is addressed.

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.