Fukuo Nakagawa

Noninvasive cerebral optical spectroscopy: Depth-resolved measurements of cerebral haemodynamics using indocyanine green

To investigate the feasibility of a newly developed, near-infrared optical spectroscopy device, we analysed measurements of the infrared tracer indocyanine green (ICG) using sensors with a single near infrared light source and multiple light detectors. Two ml of ICG dye, 1.0 mg ml-1 in concentration, were injected into the internal carotid artery during cerebral angiography in 14 adult patients. The resultant washout curves were measured bilaterally using sensors with 4 detectors spaced at 10, 20, 30 and 40 mm from the infrared light source on the right side, and 15, 25, 35 and 45 mm from the source for the left side, respectively. Washout curves were analysed to determine the relative amplitude of the ICG absorption signal and deduce each detectors penetration distance. When ICG was injected into the internal carotid artery, relative absorption increased with detector distance from the light source. No substantial difference in attenuation was observed in any of the detectors during external carotid injection of ICG. The resultant information related depth of penetration of the light with source-detector separation distances. The feasibility of the system for measuring cerebral oxygen saturation and haemodynamics noninvasively or monitoring at bedside is discussed.

Dorsal internal carotid artery aneurysms with special reference to angiographic presentation and surgical management.

SummaryAneurysms arising from the dorsal wall of the internal carotid artery are rare. The authors surgically treated twenty dorsal internal carotid artery aneurysms. Pre-operative angiographic findings were reviewed and classified into three types. Eleven aneurysms projecting superiorly on the lateral angiogram were found to be adherent to the base of the frontal lobe by the pterional approach. Five aneurysms which had been superimposed with the internal carotid artery on the lateral angiogram were found adhered to the medial surface of the temporal lobe. Four aneurysms not seen on the angiogram had no adhesion. Two aneurysms, which had not been seen on the initial angiograms, were visualized on the angiograms taken during the period of vasospasm. This type of aneurysms can be the source of a subarachnoid haemorrhage of unknown origin and requires repeated examinations. Premature rupture occured intra-operatively in five cases and postoperative bleeding was encountered in two. Clipping technique is discussed from the viewpoint of preventing intra- and postoperative rupture.

Low anterior interhemispheric approach--a narrow corridor to aneurysms of the anterior communicating artery.

Summary.Summary.Background: Many approaches for clipping anterior communicating artery (ACoA) aneurysms are reported in the literature. We describe here a new approach called “low anterior interhemispheric approach” for clipping of ACoA aneurysms.Materials and Methods: A low anterior interhemispheric approach utilizing a unilateral frontal craniotomy flap with minimal unilateral frontal lobe retraction was used in treating four patients harboring an unruptured ACoA aneurysm. The approach axis is directed to the ACoA area itself with minimal exposure to the anterior cerebral vessels.Findings: In all patients, complete neck clipping was possible with minimal brain retraction, without vascular damage and preserved olfaction.Interpretation: This approach is preferred on anatomical grounds for cases of unruptured small and medium sized ACoA aneurysms projecting anteriorly or posteriorly because the anterior communicating artery complex area can be fully visualized with minimal manipulation of the frontal lobes and anterior cerebral arteries.

Traumatic middle cerebral artery aneurysm: case report and review of the literature

Traumatic intracranial aneurysms are rare. A case of traumatic middle cerebral artery aneurysm was presented. A 66-year-old man sustained a severe head injury in a bicycle accident. Serial computed tomography and angiography showed the delayed intracerebral hemorrhage caused by the traumatic middle cerebral artery aneurysm. The aneurysm was trapped and removed. Histological examination clearly revealed the pseudoaneurysm. Traumatic middle cerebral aneurysms were reviewed.

Clinical Analysis of Internal Carotid Artery Aneurysms with Reference to Classification and Clipping Techniques

Summary An intraoperative classification of intradural internal carotid artery (ICA) aneurysms not related to the arterial division but based on their operative presentation and clipping techniques is introduced. On the basis of the surgeons view of the operative field via the pterional approach in 156 operated intradural ICA aneurysms in 143 patients, these aneurysms were classified according to their location in relation to the long axis of the ICA as either proximal, middle or distal in type and also according to their relation to the cross section of the ICA as either lateral, medial, ventral or dorsal in type. Numerically the largest in frequency is the middle type of aneurysm by axial location and the lateral type of aneurysms by cross sectional location. Eighty five percent of the lateral type aneurysms were at the arterial division. The majority of the large to giant aneurysms were of the ventral type and no dorsal type aneurysms were seen. About one third of the ICA aneurysms in this series were located free of the arterial division. All dorsal type aneurysms and most of the medial type aneurysms were not related to the arterial division. Clipping techniques were classified into perpendicular and parallel clipping, as to the direction of the clip-blades in relation to the carotid axis. The parallel clipping was further classified into forward clipping, in which a clip was applied from the distal side of the ICA, and reversed clipping, in which a clip was applied from the proximal side of the ICA. Most of the aneurysms located at the arterial division required the perpendicular clipping and those free of the arterial division required the parallel clipping. Furthermore, the forward clipping was useful for proximal type aneurysms and the reversed clipping for distal type aneurysms. For the middle type aneurysms clipping was performed bidirectionally. This classification includes all types of the ICA aneurysms located at any points along its long axis and on its cross section, and is useful for planning safe and exact clipping of the ICA aneurysms.

Optociliary veins associated with meningioma of the optic nerve sheath.

We report on the clinical symptoms and the course of a case that showed the typical findings of a meningioma of the optic nerve sheath, characterized by visual disturbances, progressive visual field defect, proptosis, secondary atrophy of the optic disc, and shunt vessels between retinal and choroidal circulation. The shunt vessel which was demonstrated in this case by fluorescein angiography is identified with the optociliary vein reported in the literature. Fluorograms also revealed peculiar vessels at the margin of the optic disc, which have not been described in association with this tumor. CT scanning and roentgenograms of the optic canal proved useful as diagnostic tools for this tumor. The tumor was removed through a frontotemporal craniotomy, preserving the optic nerve. The histopathological diagnosis was meningothelial meningioma.

Horizontal contralateral approach for the distal anterior cerebral artery aneurysm: technical note

BACKGROUND The authors present a modified interhemispheric approach for the distal ACA aneurysm to resolve several problems including the narrow surgical corridor, the difficulty of proximal control, and the aneurysmal projection toward the surgeon. METHODS We refined the positions of the patients head and the surgeon. The patients head is fixed with flexion and tilted to the contralateral side. The surgeon sits on the contralateral side of the patient and not on the cranial side. RESULTS The present approach allows the surgeon to comfortably use both hands in the horizontal operative filed, to obtain a minimum retraction of the brain, and to easily secure the proximal artery. CONCLUSIONS This modified interhemispheric approach is useful for a patient with the distal ACA aneurysm.

Anterior subtemporal approach for posteriorly projecting posterior communicating artery aneurysms

We report our experience with the anterior subtemporal approach for the posterior communicating artery aneurysm protruding posteriorly. Between 2000 and 2005, seven patients with posterior communicating artery aneurysm were operated on through the anterior subtemporal approach. The approach provided a better view than the pterional approach. This approach seems to be suitable for posteriorly projecting posterior communicating artery aneurysms. The advantages of the anterior subtemporal approach are as follows: (1) It provides a short and a direct trajectory to the aneurysm. (2) Aneurysmal neck and surrounding structures can be easily identified and secured compared with the pterional approach. (3) A previously placed clip for a middle cerebral artery or internal carotid artery aneurysm through the pterional route does not interfere with the clipping surgery for regrown or de novo posterior communicating artery aneurysms.

Relationship between Clinical and Endocrinological Features following Transsphenoidal Surgery for Acromegaly

Fourteen patients with acromegaly who had undergone transsphenoidal surgery were followed for 1 to 7 years (average, 4.3 years). Pre- and postoperative growth hormone (GH) levels, changes in the GH response to thyrotropin releasing hormone (TRH) tolerance testing, and the correlation between clinical improvement and postoperative GH and somatomedin-C levels were studied. Clinical improvement was assessed by scoring of the pre and postoperative symptoms. A significant correlation was found between the postoperative GH and somatomedin-C levels (p<0.01). All patients with postoperative somatomedin-C levels of less than 2 IU/ml, including one of the three patients whose postoperative GH levels were between 5 and 10 ng/ml, showed clinical improvement. Normal responses to TRH testing were rare and were poorly correlated with clinical improvement. These results suggest that somatomedin-C is more useful than GH in predicting clinical improvement following surgery for acromegaly.