Basal interfalcine approach through a frontal sinusotomy with vein and nerve preservation. Technical note.

The authors describe a new method for a frontal interhemispheric approach when treating craniopharyngiomas of the third ventricle or anterior communicating artery aneurysms. This technique ensures preservation of the bridging veins and the olfactory nerves. This "basal interfalcine approach" involves a craniotomy in the centrobasal portion of the frontal bone (the frontal sinus), removal of the inner tables and the crista galli, and splitting the basal portion of the falx into two leaves, through which the basal interhemispheric fissure is opened. The olfactory nerves are protected by the leaves of the falx, and the bridging veins are preserved because the approach is low enough to spare them. The surgical techniques are described together with a unilateral variation of this approach. The significance of preserving the bridging veins is discussed in connection with avoidance of postoperative contusional hemorrhage.

Unusual angiographic changes in a dissecting aneurysm of the basilar artery: case report.

A patient with unusual angiographic changes of a dissecting aneurysm of the basilar artery is presented. Initial angiography and magnetic resonance imaging revealed a typical dissecting aneurysm. However, a follow-up study demonstrated a saccular aneurysmal dilatation of the proximal part of the dissection. The importance of the follow-up study, particularly in regard to the usefulness of magnetic resonance imaging and the pathogenesis of this change are discussed.

Wrap-clipping with a Dacron mesh silastic sheet. Technical note.

A technique combining wrapping and clipping using a Silastic sheet coated with Dacron mesh is described for treatment of fusiform or broad-based cerebral aneurysms. This sheet is easily tailored to wrapping the aneurysm base while avoiding involvement of the cranial nerves or branching vessels. The sheet is semitransparent so that the caliber of the newly constructed parent artery is easily adjusted during wrap-clipping. After the aneurysm and the parent artery have been circumferentially wrapped with the sheet, aneurysm clips are applied on the sheet so that the base of the aneurysm is clipped between the two leaves of the sheet. This wrap-clipping technique avoids the risks involved in extracting the aneurysm from the parent artery. The Dacron mesh coating the outer surface and sufficient clip closing pressure are both helpful in preventing the clip blades from sliding. Similar previously reported techniques are reviewed and discussed in detail.

Thrombotic occlusion of the middle cerebral artery.

BACKGROUND AND PURPOSE: Epidemiological study of middle cerebral artery occlusion is important because the indication for extracranial-intracranial arterial bypass remains in dispute. To help clarify this issue, we investigated the prognosis of thrombotic middle cerebral artery occlusion in Japanese patients. METHODS: We studied 40 patients with thrombotic middle cerebral artery occlusion who were selected on the basis of clinical features, computed tomographic findings, and angiographic findings. Patients with causes of embolism (i.e., cardiomyopathy, valvular heart disease, cardiac arrhythmia, and carotid ulceration) were excluded. The 40 patients were classified into three groups according to the site of middle cerebral artery occlusion: there were 13 patients with occlusion of the proximal portion of the M1 segment, 13 with distal M1 segment occlusion, and 14 with occlusion of the M2 segment. RESULTS: Good collateral circulation was associated with improved outcomes both clinically and by computed tomography in patients with occlusion of the proximal and distal portions of the M1 segment but not in those with M2 occlusion. CONCLUSIONS: It is reasonable to assume that not only collateral circulation but also the site of occlusion plays an important role in the outcome of middle cerebral artery occlusion. Our finding that good collateral circulation improves the outcome for thrombotic occlusion of the proximal and distal M1 segments supports the possible benefits of such surgery.

Cranio-nasal median splitting for radical resection of craniopharyngioma.

A new surgical approach for radical resection of craniopharyngioma is presented. This approach (cranio-nasal median splitting) involves craniotomy in the centre of the frontal bone, removal of the median portion of the supraorbital bar that incorporates the nasal bone, and detachment of the medial canthal ligaments. The frontal lobes, the cribriform plates, the planum sphenoidale, and the upper nasal cavities are split in the midline. The extraventricular surface of the hypothalamus, the pituitary stalk, and the posterior portion of the Willis' arterial ring are well visualized through the midline infrachiasmatic route. The intraventricular surface of the hypothalamus is also visible in the same operative field through the lamina terminalis and/or the anterior portion of the corpus callosum. This excellent visualization is quite helpful for minimizing operative injury to the hypothalamus and the pituitary stalk whichever surface of the third ventricular floor the tumour is situated upon. Three cases of craniopharyngioma operated upon by this approach are presented. Discussions are focused not only on the indication, but on the advantages and disadvantages of this approach. The surgical techniques for reconstruction of the cranial base are also described, together with some precautions that should be taken to prevent possible postoperative complications.

Altered reactivity of hemolysate-treated cultured smooth-muscle cells from rabbit basilar artery determined by digital imaging microscopy.

During culture, smooth-muscle cells obtained from rabbit basilar arteries were examined for contractile activity by means of differential interference microscopy with a video analysis system (digital imaging microscopy system). This system proved useful for observing the contraction and ultrastructural changes of the living cells. Hemolysate-treated cells showed augmented responses to 5-hydroxytryptamine and leukotriene C4, but not to KCl. This augmented response diminished gradually during the culture period. Both a phospholipase C blocking agent, 2-nitro-4-carboxyphenyl-n,n-diphenylcarbamate (NCDC), and a myosin light chain kinase blocking agent, 1-(5-chloronaphthalenesulfonyl)-1H-hexahydro-1,4-diazepine (ML-9), suppressed this augmented response. Protein kinase C activity of the cells, as measured by Western blot analysis, did not increase during the period of culture with hemolysate. The results obtained suggest that hemolysate had the following effects on the cells: 1) acute but gradual contraction of the cells; 2) augmentation of cellular responses to vasoactive agents; and 3) progressive contraction and morphological alteration of the cells. Possible mechanisms by which hemolysate exerts these effects are discussed, taking into consideration the interrelationship between these effects.

Telecanthal approach for meningiomas in the ethmoid and sphenoid sinuses.

In three cases involving meningiomas in the ethmoid and sphenoid sinuses, transbasal spreading of the interocular distance (telecanthal approach) was used for tumor removal and reconstruction of the skull base. This telecanthal approach involves 1) bilateral en bloc removal of the superior lateral rim of the orbit, the nasal bone, and the posterior lateral wall of the orbit; 2) detachment of the medial canthal ligaments; and 3) spreading of the interocular distance. This approach provides a wide working space beneath the anterior half of the midline skull base, and needs neither a facial incision nor significant retraction of the brain. The surgical technique and its modification are described. The discussion focuses not only on comparisons with other techniques, but on the indications for this approach. Meningiomas originating in the paranasal sinuses are rare; a brief review of the literature concerning the clinicopathological features and pathogenesis is also given.

Indications for surgical treatment of putaminal hemorrhage. Comparative study based on serial CT and time-course analysis.

Serial computerized tomography (CT) scans were correlated with a precise time-course analysis of the neurological condition of 180 patients with hypertensive putaminal hemorrhage. All patients entered the study within 3 hours of the ictus. In this series, 111 patients were treated conservatively and 69 surgically. The neurological condition of each patient was measured by means of a newly proposed grading system for intracerebral hemorrhage-intracranial hemorrhage (ICH grade) which is a modification of the Glasgow Coma Scale. Serial CT scans revealed that most hemorrhages were completed within 6 hours after ictus. Based on the ICH grade at 6 hours postictus, a clinical classification of the severity of putaminal hemorrhage was defined: fulminant, rapidly progressive, slowly progressive, and nonprogressive. According to this classification, precise time courses of the ICH grade were compared between the conservative and surgical treatment groups in a 7-day postictal period. Activities of daily living at 6 months after ictus were also compared. Surgical treatment for a rapidly progressive hemorrhage appears to be beneficial if undertaken in patients under 65 years of age. Surgery in a slowly progressive hemorrhage should be considered only in a small number of patients who deteriorate neurologically with conservative treatment. In this series of patients, surgical treatment of fulminant and nonprogressive hemorrhage was not likely to improve the quality of life or functional recovery. Regardless of treatment modality, CT provided evidence that patients with anterior capsular hemorrhage (16% in this series) showed good recovery of motor and speech function.

A new intracranial Silastic encircling clip for hemostasis. Technical note.

A new encircling clip made of a silicone tube has been designed for treating accidentally injured cerebral vessels. No special holders are necessary. This clip can be tailored depending on the shape of the injured vessel. The clip is a simple and effective tool for achieving complete hemostasis.

Microsurgical thromboendarterectomy of the cavernous carotid artery--case report and surgical technique.

A 53-year-old male suffered a transient right hemiparesis and left monocular blindness. Angiography revealed 80% stenosis of the cavernous carotid artery. Microsurgical thromboendarterectomy was performed by a direct approach through Parkinson's triangle. During surgery, the carotid circulation was transiently trapped between the cervical and the supraclinoid segment and the trapped arterial lumen was irrigated with heparinized saline. Soft elastic lesion was easily removed. Cavernous carotid thromboendarterectomy through a direct approach is considered as a suitable operation for the solitary and localized stenotic lesions of the cavernous carotid artery, although this operation has not yet been reported to date.

[Management results of primary intracranial malignant lymphoma].

Nineteen cases of primary malignant lymphoma of the central nervous system were reported. The clinical characteristics, diagnostic procedure and therapeutic method, especially concerning chemotherapy, were analysed. The following conclusions were obtained: 1) histological classifications and surgical procedures were not factors involved in prognosis. 2) radiotherapy was regarded as an effective but a palliative treatment. 3) combined chemotherapy for systemic malignant lymphoma, such as VEMP, VEP, COPP, seemed to be of little use for intracranial malignant lymphoma. 4) intra-arterial administration of high-dose methotrexate, ACNU and intravenous administration of high-dose cytosine arabinoside can be expected to be a useful chemotherapeutic approach.

[Comparison of five modes of dialysis in neurosurgical patients with renal failure].

In neurosurgical patients with renal failure, dialysis entails specific problems, chief of which is increased intracranial pressure and progressive brain edema as a result of rapid lowering of the serum osmolality. Another major problem is a tendency to hemorrhage, in response to either systemic heparinization or insufficient dialysis. The authors describe the results obtained with hemodialysis (HD), continuous arteriovenous hemofiltration (CAVH), continuous ambulatory peritoneal dialysis (CAPD), continuous peritoneal dialysis (CPD), and intermittent peritoneal dialysis (IPD). Nine patients were treated with HD, one with CAVH, five with CAPD or CPD, and two with IPD. Three of the six patients treated with continuous dialysis (CAVH, CAPD, and CPD) died, whereas intermittent dialysis (HD and IPD) carried an 82% mortality rate (nine of 11 patients). The causes of death were progressive brain edema in three cases, intracranial hemorrhage in three, gastrointestinal bleeding in three, overhydration due to insufficient dialysis in one, septicemia in one, and rupture of a cerebral aneurysm in one. Continuous dialysis appeared to be superior to intermittent dialysis in these neurosurgical patients in that it produced less brain edema and was less often associated with hemorrhage due to insufficient dialysis. In HD and CAVH, systemic heparinization was also thought to account for the high incidence of hemorrhage. However, CAVH with short half-life anticoagulants may be useful in patients who have abdominal complications and are therefore not suitable candidates for peritoneal dialysis.

[Multiple cerebral venous angiomas associated with mixed pial and dural arteriovenous malformation].

Venous angioma is a relatively rare entity of vascular malformations of the brain and usually found as a solitary lesion. Cases of multiple lesions and/or coupled with other vascular malformations are extremely rare. We present the first case of multiple supratentorial venous angiomas associated with mixed pial and dural arteriovenous malformation (AVM) fed by the posterior cerebral artery, the occipital artery and the posterior meningeal artery.

Traumatic intraventricular hemorrhage: report of twenty-six cases and consideration of the pathogenic mechanism.

A series of 26 patients suffering traumatic intraventricular hemorrhage (IVH) after closed head injury is reviewed, and the pathogenic mechanism of the traumatic IVH is discussed considering the site of origin of the IVH. Computed tomographic detection of the origin of the IVH was possible in 15 patients (Group 1): 6 had frontal or temporal contusional intracerebral hemorrhage spreading into the ventricle (Subgroup A), 5 had the original hemorrhage in the caudate nucleus (Subgroup B), and 4 originally bled in the thalamus (Subgroup C). The origin of the IVH was not determined in 11 patients (Group 2): 6 had concomitant hemorrhage around the brain stem (Subgroup D), and 5 had small IVH with or without small intracerebral hemorrhage (Subgroup E). The site of impact was not uniform in Subgroup A, whereas the other four subgroups usually had frontal or occipital impact. In Subgroup A, the IVH was discovered more than several hours after trauma. In the other four subgroups, however, the IVH was detected in as short a time as 0.5 to 1.5 hours after trauma. In Subgroups B and C, the impact along the long axis of the skull and the early occurrence of hemorrhage in the basal ganglia suggest that shear injury between the perforating vessels and the basal ganglia may be the responsible mechanism. The several other possible mechanisms in Subgroups D and E are reviewed and discussed in relation to diffuse brain injury.

[Traumatic enucleation of the eye ball--report of a case and considerations concerning the pathogenic mechanism of intracranial complications].

A 48-year-old man had his left eye ball enucleated by fingers of an assailant. The optic nerve, measuring 4 cm in length, was attached to the enucleated eye ball, but there was neither a wound in his eyelids nor cerebrospinal fluid leakage from inside the orbit. He was confused, but responsive and was able to recognize other persons with his right eye. His right-eye vision deteriorated within 24 hours and was almost totally lost for about one month. Three months after the trauma his vision recovered to 0.1, but his visual field showed severe concentric narrowing. An emergency CT on admission showed a small subarachnoid hemorrhage in the suprasellar cistern, and follow-up CT scanning on day 7 demonstrated a small infarction in the left globus pallidus and putamen. Cerebral angiography performed on day 17 showed residual vasospasm of the horizontal portion of left anterior cerebral artery. Left ophthalmic artery was patent and there was no aneurysm formation either on the intracranial or on the intraorbital arteries. Literature review yielded only three cases of eye ball enucleation by an assailant. Intracranial complications reported in the literature, including those associated with eye ball enucleation caused by other mechanisms, are; contralateral visual field defect: seven cases, hypothalamic involvement: two cases, subarachnoid hemorrhage: two cases, cerebrospinal fluid leakage: one case, and meningitis: one case. The optic nerve, from just behind the eye ball to the chiasm, is reported to be 40-50 mm long, and eye ball enucleation with the optic nerve measuring 4 cm or more is quite likely to cause intracranial complications such as are cited above.

Experimental vasospasm in cultured arterial smooth-muscle cells. Part 1: Contractile and ultrastructural changes caused by oxyhemoglobin.

Smooth-muscle cells were cultured from rat aortic media, then oxyhemoglobin and other agents including serotonin, norepinephrine, and angiotensin II were added separately to the medium. Contractile and ultrastructural changes of the cells were examined with electron microscopy during the first 2 weeks of incubation. Oxyhemoglobin not only produced progressive contraction of the arterial smooth-muscle cells, but it also caused ultrastructural changes that resembled myonecrosis. In contrast, there was no evidence of progressive contraction or ultrastructural changes either in control cultures or in cultures with the other vasoactive agents. Although washout of oxyhemoglobin 3 hours after administration prevented continued contraction of the cells, washout 24 hours or longer after administration had no preventive effect. Judging from these results and from the fact that the culture medium was changed every 2 days, it is unlikely that accumulation of exogenous vasoactive agents caused these changes. The contraction and suggestive myonecrosis of the arterial smooth-muscle cells are probably caused by some intrinsic process initiated by oxyhemoglobin. The culture of cerebral arterial smooth-muscle cells requires further technical improvement; nevertheless, these results obtained with the smooth-muscle cells of rat aortic media indicate that arterial smooth-muscle cells in culture provide a promising new experimental model for chronic in vitro study of cerebral arterial spasm. It is suggested from these results that cerebral arteries are particularly prone to vasospasm because of structural differences as compared to noncerebral arteries.

Subdural tension pneumocephalus following surgery for chronic subdural hematoma.

The computerized tomography (CT) findings were analyzed in five cases of subdural tension pneumocephalus following surgery for chronic subdural hematoma. They were compared with CT scans in 14 cases of asymptomatic subdural pneumocephalus. In this study, two new CT findings were identified that suggest increased tension of the subdural air. Subdural air separates and compresses the frontal lobes, creating a widened interhemispheric space between the tips of the frontal lobes that mimics the silhouette of Mt. Fuji. The presence of air between the frontal tips associated with massive air inclusion over the frontal lobes presumably indicates increased tension of the subdural air. The "Mt. Fuji sign" was seen in four of the five cases with subdural tension pneumocephalus. The other finding was the presence of multiple small air bubbles scattered through several cisterns ("air bubble sign"). It is postulated that these air bubbles enter the subarachnoid space through a tear in the arachnoid membrane caused by increased tension of air in the subdural space. This finding was seen in four cases with subdural tension pneumocephalus. These two CT findings are helpful in making a diagnosis of subdural tension pneumocephalus following surgery for chronic subdural hematoma.

Computed tomography of intracranial chondroma with emphasis on delayed contrast enhancement.

Intracranial chondroma is an unusual cartilaginous tumor originating from the base of the skull. We report on two cases of intracranial chondroma that showed delayed contrast enhancement on CT after high-dose administration of contrast medium. This CT feature may be useful to differentiate chondromas from other tumors of the skull base such as meningiomas and neurinomas.

[Subdural tension pneumocephalus following surgery of chronic subdural hematoma].

Subdural tension pneumocephalus (TP) following surgery for chronic subdural hematoma was analyzed in 5 cases from clinical standpoints of view, especially from CT findings. The cases were compared with 14 cases of subdural asymptomatic pneumocephalus (AP). The TP tends to complicate elderly patients who showed a poor re-expansion of the brain after irrigation of bilateral chronic subdural hematoma. In such patients, it is difficult to make an exact diagnosis of TP because of residual mass effect of the evacuated hematoma. Significance of mass effect caused by subdural air has been discussed in the literature only little. In this study, we found two new CT findings suggesting increased tension of subdural air. First, the subdural tensive air separates and compresses the frontal lobes. The compressed frontal lobes with widened interhemispheric space between the frontal poles mimic the silhouette of Mt. Fuji. We called this CT finding "Mt. Fuji" sign. The presence of air between the frontal poles associated with massive air over the frontal lobes presumably indicates an increased tension of the subdural air. "Mt. Fuji" sign was seen in 4 cases out of 5 TP cases. Another sign is the presence of multiple small air bubbles in the subarachnoid space, especially in the cisterns. We proposed that these air bubbles were trapped in the subarachnoid space through a tear of the arachnoid membrane which is caused by increased tension of air in the subdural space. This finding was present in 4 cases with TP. We emphasize that these two CT signs are helpful to make an accurate diagnosis of TP following surgery for chronic subdural hematoma.