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Biomedical subjects

V V Halbach

Publications and source records attributed to V V Halbach.

160 records · Page 9Linked to original sources

Transarterial occlusion of solitary intracerebral arteriovenous fistulas.

Congenital solitary arteriovenous fistulas unassociated with arteriovenous malformations are rare. Five patients with this condition were treated by endovascular procedures: three by transarterial balloon occlusion and two by coil and silk suture embolization. Of the three patients treated by balloon occlusion, complete angiographic obliteration was achieved in two, and one patient had subtotal occlusion resulting from proximal balloon placement. Two of these patients subsequently underwent surgical excision without incident. There were no complications. Two patients were treated with a combination of platinum coils and silk suture embolization, which resulted in complete angiographic obliteration in both. There was one asymptomatic complication consisting of a coil migrating through the fistula and lodging in the lung. While detachable balloons have advantages in allowing test occlusion prior to detachment, the traction required for detachment can limit accurate deposition and place the feeding arteries under undue stretch. Coil and silk suture embolization enable more precise deposition and are probably the agent of choice for closure of solitary arteriovenous connections within the central nervous system.

Adolescent↗

Venography and venous pressure monitoring in dural sinus meningiomas.

This study was undertaken to determine the impact of dural sinus venography and pressure measurements in the evaluation of patients with meningiomas involving the dural sinuses. Of three patients who had MR imaging, arteriography, and dural sinus venography, the latter method better delineated the site and extent of tumor invasion in all three patients. Pressure measurement in one patient reflected the severity of the hemodynamic compromise resulting from narrowing of the transverse sinus. In one patient, dural sinus venography confirmed patency of the superior sagittal sinus that was unsuspected on MR scans and arteriograms. A test occlusion of the area of stenosis in the third patient allowed the surgeon to sacrifice that segment of the sinus without deficit. Dural sinus venography is a useful adjunct to arteriography and MR imaging in the evaluation of invasive meningiomas.

Adult↗

Transluminal angioplasty of the vertebral and basilar artery.

Transluminal angioplasty of brachiocephalic vessels for atherosclerotic lesions is now being performed in selected cases. We have thus far treated 17 cases of vertebral artery stenosis and one case of basilar artery stenosis by intravascular balloon dilatation techniques. Clinical presenting symptoms included vertebral basilar insufficiency, repeated transient ischemic attacks (TIAs), and multiple strokes. We performed successful transluminal angioplasty in 16 patients with marked narrowing (greater than 70%) of the dominant vertebral artery from atherosclerosis. One patient with basilar artery stenosis with tandem atherosclerotic lesions was also treated by angioplasty techniques. Repeat angiography at 3- to 12-month intervals has revealed continued patency at the angioplasty site. Complications occurred in our one patient with basilar artery angioplasty, who suffered a brainstem infarction after treatment, and in one patient who had a TIA after bilateral vertebral artery angioplasty. Two other patients had residual vertebral stenosis but remained asymptomatic after the procedure. All other patients who had successful dilatation were asymptomatic at 6 months to 2 years (mean, 15 months) of follow-up. These initial studies indicate that vertebral artery angioplasty may be effective for treating high-grade atherosclerotic lesions and for improving blood flow to the posterior circulation. Angioplasty of the basilar artery is technically more difficult and has a higher degree of risk because of the many perforating branches supplying the brainstem.

Aged↗

Pneumosinus dilatans of the sphenoid sinus.

Four cases of pneumosinus dilatans of the sphenoid sinus are reported, supplementing the eight cases previously reported in the literature. This rare entity is characterized by expansion of a paranasal sinus that contains only air. In one patient, severe visual loss due to compression of the optic canal by the adjacent enlarged sinus was seen. Galactorrhea occurred in one patient, and three of the four patients reported headaches. There was dehiscence of the sinus roof in two cases, which apparently resulted in a cerebrospinal fluid fistula in one. Previous reports of this entity are reviewed, and the radiographic findings and clinical presentations are discussed. It is proposed that the term "pneumosinus dilatans" be used to describe all dilated, air-filled sinuses with outwardly bulging walls when the primary cause is uncertain.

Adolescent↗

Normal perfusion pressure breakthrough occurring during treatment of carotid and vertebral fistulas.

Of the 185 carotid and vertebral fistulas treated by the authors over the past 10 years, five developed neurologic deficits after abrupt closure of their fistulas. The earliest case, treated initially by proximal surgical carotid occlusion, presented 32 years later with cerebral steal symptoms from the large, long-standing carotid cavernous fistula. Upon completion of a surgical trapping procedure, there was immediate massive cerebral edema, brain herniation, and death. In the remaining four patients (three vertebral fistulas and one with carotid cavernous fistula), all treated by transvascular embolization techniques, neurologic deficits occurred coincidentally with the abrupt closure of the fistula and resolved with reestablishment of fistula flow. This indicated that the cerebral vasculature is unable to tolerate the reestablishment of normal cerebral perfusion after abrupt closure of the fistula. All four patients were treated with staged or slow occlusion of their fistulas, which resulted in complete fistula closure without permanent neurologic sequelae. All five patients who developed symptoms consistent with normal perfusion pressure breakthrough had large, long-standing fistulas, ranging in duration from 9 to 32 years. Two of the five patients developed slowly progressive neurologic deficits consistent with cerebral steal prior to treatment. This sign was not observed in the 180 patients who did not develop symptoms during treatment. We conclude that patients with carotid or vertebral fistulas of long duration, particularly those with cerebral steal symptoms, are at risk to develop neurologic deficits related to perfusion breakthrough if their fistulas are abruptly closed. Staged or gradual closure may prevent this potentially devastating complication.

Adult↗

Intraoperative digital subtraction neuroangiography: a diagnostic and therapeutic tool.

We report our experience with intraoperative digital subtraction neuroangiography to demonstrate its application as a diagnostic and therapeutic technique. Intraoperative neuroangiography was performed on 53 occasions in 43 patients using a portable imaging system. Thirty-two procedures were performed for diagnostic purposes after resection of arteriovenous malformations, clipping of aneurysms, or carotid endarterectomy. Unexpected problems were disclosed in seven cases and were surgically remedied immediately in four. In addition, angiography was used as a therapeutic tool in 21 cases to facilitate intraoperative embolization of a vascular lesion or to enable the angioplasty of a vessel inaccessible without direct surgical exposure. We found that by allowing a combined interventional neuroangiographic and neurosurgical approach, intraoperative angiography opened new avenues for treatment of intracranial vascular abnormalities.

Cerebral Angiography↗

High-risk dural arteriovenous fistulae of the transverse and sigmoid sinuses.

Dural arteriovenous fistulae of the transverse and sigmoid sinuses are highly variable in symptomatology and prognosis. However, we have identified a subgroup of patients who have a high risk of hemorrhage and dementia due to severe venous overload caused by high arterial flow into the fistulae and by occlusive changes of the transverse and sigmoid sinuses. Three representative cases selected from 31 patients with dural arteriovenous fistulae of the transverse and sigmoid sinuses are presented, and 45 reported similar cases are reviewed to discuss pathophysiology and problems encountered during treatment.

Aged↗

Treatment of dural arteriovenous malformations involving the superior sagittal sinus.

We report the diagnosis and treatment of seven dural arteriovenous malformations involving the superior sagittal sinus. The most common presenting symptom was headache, although two patients presented with hemorrhage. Embolization alone effected a complete cure in four patients, while a combination of embolization and surgery was used in the remaining three patients. The first of these had intraoperative exposure and embolization of multiple feeding branches of both middle meningeal arteries, which resulted in a complete cure without deficits. The second patient had multiple embolizations and surgeries with eventual resection of the involved sagittal sinus to effect a complete cure, which was complicated postoperatively by paraparesis. The third patient had preoperative embolization and subsequent surgical resection of the superior sagittal sinus, resulting in a complete cure without deficits. Because of their unique midline location, multiplicity of arterial feeders, and critical venous drainage, dural malformations involving the superior sagittal sinus often require unusual and aggressive forms of therapy.

Adult↗

Platinum wire: a new transvascular embolic agent.

Standard Gianturco and "mini" coils cannot be used with some of the present microcatheter systems. However, occasions arise in which metallic coils would be an ideal embolic agent in vascular structure accessible only to a tracker (2.2-French) catheter system. We performed nine embolization procedures in eight patients with arteriovenous fistulas using platinum coils as an embolic agent. Fistulas were completely occluded in six of the nine cases. In several cases, platinum wire embolization was augmented with other agents. Complications occurred in two cases, neither resulting in permanent neurologic deficits. Advantages of using platinum coils included availability, radioopacity, thrombogenicity, biocompatibility, and delivery through microcatheters, specifically the tracker catheter system.

Adult↗

Transvenous embolization of direct carotid cavernous fistulas.

Of 165 cases of direct carotid cavernous fistula, 14 (8.5%) were treated from a transvenous approach. Twelve of these were treated through the inferior petrosal sinus and one through the superior ophthalmic vein. In one patient, both approaches were used. The embolic agents were as follows: five patients had balloons only, four patients had minicoils alone, three patients had coils and liquid adhesives, one had balloons and coils, and one had balloons and liquid adhesives. Among the patients who were treated from a transvenous approach, three had an occluded carotid artery caused by trauma, nine failed transarterial balloon attempts, and one had a prior trapping procedure. In the remaining patient, who had Ehlers-Danlos syndrome, a transarterial approach was judged to be too dangerous. This patient suffered a fatal pontine hemorrhage after subtotal transvenous occlusion of the carotid cavernous fistula with diversion of flow into cortical veins. Another complication occurred when the inferior petrosal sinus was perforated during catheterization, causing a small subarachnoid hemorrhage. The tear was immediately closed with minicoils, and surgical exposure and embolization resulted in complete cure. Of the remaining 12 patients treated, 11 were completely cured and one showed angiographic and clinical improvement. Transarterial balloon embolization remains the procedure of choice in the treatment of symptomatic carotid cavernous fistulas; however, transvenous embolization is an alternative when the arterial route fails.

Adult↗

Microcatheter retrieval device for intravascular foreign body removal.

A microcatheter foreign body retrieval device is described and its first two clinical applications are presented. The device functions identically to larger loop snare retrievers. It permits access to small vessels and was successful in its first clinical applications.

Adult↗