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Self-retaining retractors may be useful in spinal tumor surgery. In this study, the tumors were retracted away from the surrounding tissue by pronged hooks attached to flexible self-retaining retractors; by this process, we could avoid placing pressure on the spinal cord. A clear dissection plane was exposed between the underside of the tumor and the surrounding spinal cord, so that the surgeon had both hands free to perform the operation. Two retractor base systems were used: 1) Sugita's multipurpose headframe for the cervical region, and 2) a newly designed U-shaped, table-fixed retractor base for the thoracic and lumbosacral regions. Most retracting instruments used in cranial surgery can be used with either system.

The surgical treatment of large pituitary adenomas with suprasellar extensions has been controversial. To elucidate the indications for transsphenoidal surgery of large adenomas and to evaluate the techniques for removing the suprasellar portions of the tumors, surgical procedures on 100 consecutive patients with suprasellar extensions of nonfunctioning pituitary adenomas were retrospectively investigated. Patients were followed up for 1 to 12 years (mean, 4.5 yr). One hundred twenty-five transsphenoidal operations were performed on 100 patients. The removal of each suprasellar tumor was facilitated by the placement of a lumbar subarachnoid catheter and the injection of lactated Ringer's solution or saline. This method was used in 77 operations and was effective on 60 of 72 adenomas with < 30-mm suprasellar extensions (Hardy's Grades A, B, and C) but not on those that were fibrous or dumbbell-shaped. The descent of the remaining suprasellar tumor was facilitated by keeping the sella and sellar floor open with an intrasellar drain, and the subsequent removal was achieved with staged transsphenoidal operations. Of nine fibrous or dumbbell-shaped adenomas with 10- to 30-mm suprasellar extensions, gross total removal in eight was achieved by the open sella technique and two-stage transsphenoidal operation, whereas one required transcranial surgery. Adenomas with > 30-mm suprasellar or lateral extensions (Grade D) could not be removed sufficiently by transsphenoidal operations, except one adenoma for which a subtotal removal was achieved in the third staged operation. The disease-free rate 10 years after operation was 74% for all patients: 91% for Grade A, 74% for Grade B, and 61% for Grade C.(ABSTRACT TRUNCATED AT 250 WORDS)

In an attempt to clarify the characteristics of the pterional routes to the basilar bifurcation aneurysm, 65 consecutive surgical cases were retrospectively analyzed concerning the size of the aneurysm, the height of the aneurysm neck, the length of the clip blades, and the direction of clip application. Clipping was performed through the pterional route in 59 cases consisting of 14 opticocarotid and 45 retrocarotid routes. A subtemporal approach was performed for six low-positioned aneurysms. The opticocarotid approach was undertaken because of the following situations: 1) laterally protruded and/or highly sclerotic internal carotid artery (n = 8); 2) long, redundant A1 segment (n = 3); 3) an associated aneurysm of the internal carotid artery obstructing the retrocarotid space (n = 2); and 4) a short and/or large posterior communicating artery obstructing the retrocarotid space (n = 1). The range in height of the aneurysm neck was narrower in the opticocarotid approach (1-10 mm) than in the retrocarotid approach (-7-15 mm). The direction of clip application on the axial plane was more anteriorly deviated in the opticocarotid approach (41.4 +/- 12.8 degrees from the glabella-inion line) than in the retrocarotid approach (58.8 +/- 11.1 degrees; P = 0.01). The retrocarotid route (n = 45) was further subdivided into the medial or lateral retrocarotid routes, depending on the medial or lateral side to the posterior communicating artery, respectively. The medial retrocarotid approach (n = 9) made it possible to reach relatively high-positioned aneurysms (7.0 +/- 3.9 mm) compared with the lateral retrocarotid approach (4.2 +/- 4.7 mm; n = 29).(ABSTRACT TRUNCATED AT 250 WORDS)

Primary intraosseous orbital hemangiomas are rare tumors. Only 25 cases have been reported in the literature. Very few of them have multiple orbital bone involvement. We report a case with extensive involvement of the orbital roof, the medial and lateral walls of the orbit, and the lesser and greater wings of the sphenoid, and describe a unilateral extradural frontotemporal approach to excise the tumor and decompress the right superior orbital fissure and both optic nerves. A brief clinical and radiological review of the literature is presented.

Unexplained intraoperative or postoperative hemorrhage occurs in certain cases in the surgery of large arteriovenous malformations (AVMs), which are defined as those with maximal diameter of the nidus larger than 5 cm. Immediate postoperative angiograms were evaluated with reference to whether such hemorrhage could be predicted. Immediate postoperative angiograms were taken in 12 patients with large AVMs on the day after the operation during which the AVM was removed. In five of six AVMs located in the distal cerebral hemisphere, a hypervascular network was seen in the vicinity of the removed nidus on the immediate postoperative angiogram. The unexplained hemorrhage occurred in four of the five cases with the hypervascular network. In the remaining six patients with AVMs, the hypervascular network was not observed and they did not develop hemorrhage; the AVMs were located either close to the arterial circle of Willis or in the cerebellum. We believe that the hypervascular network seen on the immediate postoperative angiogram after the removal of a large distal AVM is an important sign predicting the likelihood of unexplained intraoperative and postoperative hemorrhage development. We call this perinidal hypervascular network "modja-modja vessels" because it resembles shaggy hair. The mechanism of its appearance and the pathogenesis of the unexplained intraoperative and postoperative hemorrhage are discussed.

In order to understand the effects and the direction of pressure transmitted from a mass lesion through various brain structures, miniature strain gauges were inserted in different brain locations in eight anesthetized monkeys. Mass lesions were created by inflating a balloon in either of two locations--subcortical in four animals (Group I) and deep (lateral to the caudate nucleus) in the other four animals (Group II). Anterior-posterior directed pressures were thus measured from a gauge placed in the parietal lobe, and lateromedially directed pressures (LM-dPs) were measured from gauges in the temporal lobe and midbrain. Intracranial pressure, systemic mean arterial pressure, and cerebral blood flow were also monitored. After balloon inflation was begun, temporal changes in pressure were recorded from gauges as percentage increase or decrease from baseline measurements. In both groups, balloon inflation caused a gradual increase in the parietal lobe anterior-posterior directed pressure with a concomitant increase in intracranial pressure and a decrease in cerebral blood flow. The temporal lobe gauge in Group I recorded an initial negative followed by a positive LM-dP with further balloon inflation. In Group II, this gauge recorded a positive LM-dP throughout. The midbrain gauges in both groups recorded an initial positive followed by a negative LM-dP. This reversal in the direction of pressure in the midbrain occurred just before the supratentorial pressure reached a peak and was noted to be concurrent with a sudden rise in mean arterial pressure and a decline in cerebral blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

A 34-year-old woman with primary choroid plexus papilloma occurring in the suprasellar region is reported. No connection with the ventricular system was found during intraoperative observations. The findings of pathological examinations such as hematoxylin and eosin staining, transthyretin (prealbumin) immunoreactivity, and electron microscopy were consistent with choroid plexus papilloma. Radiologically, it was extremely difficult to differentiate from tuberculum sellae meningioma. To our knowledge, this is the first case of primary choroid plexus papilloma in this location reported in the literature.

Bilateral, symmetrical, experimental aneurysms were produced with anastomosed vein flap in the carotid arteries of 24 mongrel dogs. Aneurysms were occluded with latex or silicone balloons on each side and observed angiographically from 2 weeks to 2 months. A histopathological study was performed subsequently using light and scanning electron microscopy. Rupture after balloon embolization occurred in five aneurysms; all of which were incompletely occluded by a silicone balloon. On subsequent angiograms, four silicone balloons and one latex balloon were found to have migrated into the aneurysm, resulting in aneurysmal expansion. Parent artery occlusion was more common with latex balloons than silicone balloons. Histopathologically, residual fresh thrombi, decreased proliferation of fibroblasts within the aneurysmal cavity, and poor endothelialization were present around the silicone balloon. These results suggest that the intra-aneurysmal organization, as seen in the aneurysm occluded by the silicone balloon, will be delayed because the balloon is not fixed within the aneurysm, and that this free-floating and rotating balloon causes repeated trauma to the aneurysm wall, contributing to subsequent enlargement and rupture of the aneurysm. The superior antithrombogenic nature of silicone may be responsible for the bias of such phenomena toward the silicone balloon.

Two cases of giant aneurysm of the horizontal segment of the anterior cerebral artery (A1) are presented. The rare occurrence of a giant aneurysm in this location necessitates evaluation of the cross-flow through the anterior communicating artery when planning surgical strategy. On the basis of angiographic findings, trapping of the A1 on both sides of the aneurysm neck was performed in Case 1, and aneurysmorrhaphy utilizing an angioplastic multiple-clipping method of A1 endarterectomy was accomplished in Case 2. The postoperative courses of both patients were satisfactory.

Dynamic properties of seven kinds of self-retaining retractors were examined by analyzing the stress-strain curve of the flexible arm under load. The stress that generated a remaining strain of 1 mm was about 80% of the maximum stress of the fixed flexible arm, and was a suitable indicator of the ability of a retractor under load. It had good correlation with the fixing torque of the flexible arm and was also influenced by the diameter of the arch of the fixed flexible arm. For all three commercially available retractors, the strongest resistance was obtained when the flexible arm was arranged in a semicircular shape with a diameter of 20 cm, regardless of the length of the arm. The retractor made of titanium alloy was superior to the retractor of the same shape made of stainless steel for vertical load, regardless of different arm-fixing torques. The tapered flexible arm of the Mizuho titanium retractor showed greater resistance to loading than a nontapered one at stronger arm-fixing torques. The Aesculap Leyla retractor had different dynamic properties from the Mizuho stainless retractors, despite their similarity in shape. The Leyla retractor was weaker than the Mizuho stainless retractors for vertical loading but stronger for horizontal loading. These experimental observations may be helpful when applying a self-retaining retractor during surgery.

The authors report a case of cranial plasmacytoma with multiple myelomas and palsy of the lower cranial nerves. The osteolytic lesion adjacent to the jugular foramen was demonstrated by an angiogram to be exceedingly hypervascular, with arteriovenous shunting resembling that seen in paragangliomas. Forty-five cases of cranial and intracranial plasmacytoma from the literature were reviewed. The findings indicate that a cranial plasmacytoma commonly appears to be a hypervascular tumor, whereas most dural tumors or intraparenchymal tumors have poor vascularity.

The authors describe a 42-year-old woman with systemic xanthogranulomatosis and bilateral intraorbital tumors, who subsequently developed multiple lesions of the intracranial dura mater, spinal cord, retroperitoneum, pericardium, and mediastinum. Systemic xanthogranulomatosis is histologically similar to systemic Weber-Christian disease, except for the absence of subcutaneous panniculitis. Immunohistochemical studies suggest that this clinical entity can be differentiated from histiocytosis X, because foamy cells in systemic xanthogranulomatosis demonstrate macrophages but not T-zone histiocyte markers. Differentiation of this disease from other intracranial xanthogranulomas and treatment are discussed.

The role of blood components in cerebral vasospasm was evaluated using an in vivo canine model. An intracisternal injection of 5 ml of washed red blood cells (RBCs) and platelet-rich plasma (PRP) resulted in acute vasospasm of the basilar artery as seen by angiography. This was comparable with the degree of vasospasm induced by an injection of the same amount of whole blood. Repeated injections of blood components or whole blood on Days 1 and 3 induced chronic vasospasm, as shown by angiography on Day 7. Results clearly indicate that chronic vasospasm was produced by RBCs and PRP, and it was in a dose-dependent manner with increasing concentrations of RBCs (hematocrit: 30, 50, and 70%). The vasospasm induced by both components closely reproduced that seen with whole blood. Neither acute nor chronic vasospasm induced by blood component injection was associated with clot formation in the subarachnoid space, as confirmed by an autopsy. These results suggest that the extravasation of RBCs and PRP into the subarachnoid space produces cerebral vasospasm by mechanisms independent of blood clot formation.

We have designed a multipurpose cervical frame to use with our operative head fixation system and have used it in 60 cervical spinal operations including anterior, posterior, lateral, and transoral approaches, with satisfactory results. We emphasize the following advantages of this system: (a) Both stability and an exact position of the cervical spine can be maintained during operation. (b) Positioning of patients for operation, including those with a halo vest, is efficiently carried out with safety and ease. (c) Our newly designed cervical frame enables exact and refined intraoperative retraction with various kinds of retractors. (d) When microsurgery is performed, the surgeon can sit at the patient's head in an operating chair.

A newly designed operator chair is suspended by a floor stand and a horizontal arm that rotates and is adjustable for length. The suspension system is equipped with magnetic locks that enable the surgeon instantaneously to take desired positions in a horizontal plane. The height of the chair is controlled electrically. The foot plate, which is in one piece with the chair, has 18 switches for the microscope, chair, bipolar coagulator, camera, and so on. This comfortable and multifunctional chair is an important microneurosurgical tool not only for minimizing the physical fatigue of the surgeon but also for performing refined techniques.

A new sterilization system for the operating microscope is introduced. The system, which uses formaldehyde vapor, has three advantages: (a) Rapid sterilization can be achieved with the microscope in place in the operating room within one-half hour. (b) The lens assembly of the microscope is protected against damage through ammonia neutralization and fresh air ventilation. (c) The microscope can be used immediately after sterilization without unpleasant odor or irritation of the eyes and nose.

We have operated on 16 cases of arteriovenous malformation (AVM) in and around the sylvian fissure. We call these lesions "sylvian fissure AVMs" and classify them into four subdivisions, namely, pure, lateral, medial, and deep AVMs. By others, they have been variously called AVMs of the basal ganglia, insula, anterior choroidal artery, frontal lobe, or temporal lobe. These sylvian fissure AVMs showed similar angiographic findings: the feeders in all cases were branches of the middle cerebral artery; in some cases, additional feeders from the anterior and posterior choroidal and posterior communicating arteries were present also. We describe the characteristic features of these AVMs from the anatomical and surgical points of view. The surgical results were satisfactory in 15 cases (no additional neurological deficits), and 1 patient died.

The authors have designed various implants made of alumina ceramic for neurosurgical use. They were used for reconstruction of the sellar floor and orbital wall and for cranioplasty to repair bone defects in both the convexity and the suboccipital region. Burr hole and sphenoid buttons were made to prevent postoperative dents in the skin. A ceramic-silicon sponge was developed as a marker prosthesis for neurovascular decompression. There were no untoward side effects such as infection or rejection by recipient tissue in humans or dogs. The advantages and disadvantages of the material are discussed.

We report a rare case of supra- and infratentorial arteriovenous malformations (AVMs), which were separate and consisted of aneurysmal dilations with two or three afferent arteries and efferent veins. Surgical resections were performed without the occurrence of additional neurological deficits. We discuss the treatment of multiple AVMs and stress that size and the structures involved are more important factors in the prognosis than the multiplicity of the lesions.