Grant B. Hieshima

Five year results of linac radiosurgery for arteriovenous malformations: outcome for large AVMS

PURPOSE For radiosurgery of large arteriovenous malformations (AVMs), the optimal relationship of dose and volume to obliteration, complications, and hemorrhage is not well defined. Multivariate analysis was performed to assess the relationship of multiple AVM and treatment factors to the outcome of AVMs significantly larger than previously reported in the literature. METHODS AND MATERIALS 73 patients with intracranial AVMs underwent LINAC radiosurgery. Over 50% of the AVMs were larger than 3 cm in diameter and the median and mean treatment volumes were 8.4 cc and 15.3 cc, respectively (range 0.4-143.4 cc). Minimum AVM treatment doses varied between 1000-2200 cGy (median: 1600 cGy). RESULTS The obliteration rates for treatment volumes < 4 cc, 4-13.9 cc, and > or = 14 cc were 67%, 58%, and 23%, respectively. AVM obliteration was significantly associated with higher minimum treatment dose and negatively associated with a history of prior embolization with particulate materials. No AVM receiving < 1400 cGy was obliterated. The incidence of post-radiosurgical imaging abnormalities and clinical complications rose with increasing treatment volume. For treatment volumes > 14 cc receiving > or = 1600 cGy, the incidence of post-radiosurgical MRI T2 abnormalities was 72% and the incidence of radiation necrosis requiring resection was 22%. The rate of post-radiosurgical hemorrhage was 2.7% per person-year for AVMs with treatment volumes < 14 cc and 7.5% per person-year for AVMs > or = 14 cc. CONCLUSION As AVM size increases, the dose-volume range for the optimal balance between successful obliteration and the risk of complications and post-radiosurgical hemorrhage narrows.

Direct endovascular thrombolytic therapy for dural sinus thrombosis

Three patients, ages 51 to 71 years, sought treatment for symptomatic dural sinus thrombosis with occlusion and were treated by direct sinus perfusion with urokinase. All three patients had a dural arteriovenous fistula; one involved the inferior petrosal sinus and two involved the transverse sinus. Clinical findings included papilledema, diminished visual acuity, decreased mentation, and cranial nerve palsies. Diagnosis was made by cerebral arteriography and confirmed by sinus venography. All three patients were treated by a transjugular direct infusion of urokinase. In one patient, a transfemoral venous approach used initially was discontinued because of an infection. The period of continuous infusion for thrombolysis ranged between 4 and 10 days. In two patients, the clinical signs and symptoms improved with angiographic evidence of clot lysis and dural sinus recanalization. Angiography indicated that one patient had a partial resolution of a clot in the torcular herophili and transverse sinus but showed no clinical improvement. These preliminary results suggest that transjugular local infusion of thrombolytic agents can be an effective treatment for symptomatic, thrombosed dural sinuses. This selective lysis avoids thrombolytic effects that could aggravate or produce systemic hemorrhagic complications.

Intravascular balloon dilatation therapy for intracranial arterial vasospasm: patient selection, technique, and clinical results

Patients presenting with symptomatic intracranial arterial vasospasm are now being treated by interventional neurovascular techniques in selected cases. From a percutaneous transfemoral approach, a custom-designed silicone microballoon can be guided through the intracranial vessels, and inflated to dilate the spastic vessel(s). This technique has been useful for both focal and diffuse areas of spasm. In clinical trials, 28 patients, ranging in age from 15–73 years have been treated. A total of 99 vascular territories have been successfully dilated in both the anterior and posterior circulations. Clinical improvement following treatment was observed in 17 cases (60.7%). Technical complications directly related to therapy included 2 cases (7.1%) of vessel rupture. In long term clinical follow-up 17 patients (60.7%) had good to excellent outcome, 2 patients (7.1%) remained in poor condition, and 9 patients (32.1%) died despite therapy. In patients presenting with symptomatic intracranial arterial vasospasm who are unresponsive to medical therapy, treatment by balloon angioplasty techniques may help to improve cerebral perfusion and clinical outcome of the patient.

Dural arteriovenous fistulas supplied by ethmoidal arteries

Eight patients with dural arteriovenous fistulas (DAVFs) located on the floor of the anterior cranial fossa and supplied by enlarged ethmoidal branches of the ophthalmic artery are described. Five patients showed the classical symptom of intracerebral hemorrhage (all five had ipsilateral frontal lobe hematomas and one also had an associated a subdural hematoma). Two patients exhibited atypical symptoms of proptosis, chemosis, elevated intraocular pressure, and loss of vision secondary to an ethmoidal DAVF, which drained posteriorly to the cavernous sinus. The eighth patient exhibited proptosis and chemosis secondary to a cavernous sinus DAVF and was incidentally found to have an asymptomatic ethmoidal DAVF. One additional patient had two separate dural fistulas: one located on the cribriform plate and the second located in the posterior fossa. Seven of the eight patients were cured by surgical excision of the fistula site; in the remaining patient spontaneous obliteration followed a surgical procedure for a cavernous DAVF. DAVFs involving the floor of the anterior cranial fossa usually present with hemorrhage, but can present with ocular symptoms or be entirely asymptomatic and are effectively treated by surgical excision of the fistula site.

Interventional neuroradiological management of vein of Galen malformations in the neonate.

Since 1978, the authors have seen 14 neonates with vein of Galen malformations who were born with severe congestive heart failure. The 5 infants treated before 1983 underwent craniotomy and clipping of feeding vessels; all died in the perioperative period. Since 1983, 8 neonates have been treated with combined arterial and venous interventional neuroradiological techniques; 6 infants survived. Two-dimensional echocardiography, color Doppler flow imaging, and pulsed Doppler ultrasound were used to assess blood flow within the malformation before and after staged transluminal embolic procedures were performed. The results of the diagnostic studies and the clinical status of the infants were used to evaluate the success of embolic therapy and the need for further neuroradiological intervention.

Transarterial Embolization of Vertebral Hemangioma

PURPOSE The authors retrospectively reviewed their 4-year clinical experience to determine the role of transarterial embolization in the treatment of symptomatic vertebral hemangioma. PATIENTS AND METHODS Eight patients (age range, 12-56 years) underwent a total of 10 embolization procedures; one patient underwent three procedures. The lesions were located between T-5 and L-5, and all patients presented with pain and symptoms referable to the lower extremities. RESULTS Embolization was technically successful in all patients, and no complications were encountered. Six of eight patients underwent surgery within 48 hours of embolization; four of the six showed significant clinical improvement immediately after surgery and on follow-up (average, 34 months). Two patients did not improve postoperatively. Two patients initially underwent embolization as the sole therapy. The first refused surgery and did not improve clinically; the second underwent two embolization procedures without clinical improvement and eventually underwent a third followed by surgery, which resulted in clinical improvement. All patients were hemodynamically stable during surgery, and blood loss was not problematic in any patient. CONCLUSIONS Overall, surgery was an effective treatment for symptomatic vertebral hemangioma and the authors conclude that transarterial embolization of vertebral hemangioma is a safe and efficacious adjunctive procedure to such surgery. However, embolization was not as promising as a sole therapeutic modality in this small group of patients.

Thrombolytic Therapy in Acute Stroke

PURPOSE To report the safety and efficacy of local, direct, intra-arterial and intravenous fibrinolysis treatment in selected cases of clinically symptomatic patients with acute occlusion of the intracranial cerebral arteries and dural sinuses. METHODS Patients with acute progressive neurological deterioration, in spite of systemic anticoagulation and/or antiplatelet medications, presenting with occlusion of a major intracranial cerebral artery or dural sinus were tested. From a transfemoral approach through a guiding catheter, a 2.5F microcatheter was guided directly into the intracranial cerebral circulation and embedded within the clot. Infusion of urokinase was then performed directly into the thrombus until lysis was attained. RESULTS In 36 total patients, 27 cases were treated for an acute arterial occlusion in 45 vascular territories. Clinically, there was neurological improvement in 18 (66.7%) cases. Complications directly related to therapy included symptomatic intracranial hemorrhage in three cases (11.1%), which included 1 case (3.7%) of vessel perforation. In 8 (29.6%) patients, there was no evidence of clinical improvement, and in long-term follow-up there were 9 (33.3%) patient deaths. Nine patients were treated for an intracerebral dural sinus thrombosis in ten vascular territories by local urokinase infusion. In 7 (77.8%) cases, there was angiographic evidence of clot lysis and clinical improvement of the patients neurological condition. Minor complications including infection and noncerebral sites of bleeding occurred in 3 (33.3%) patients, requiring adjustment in urokinase infusion therapy. CONCLUSION Local, direct intra-arterial or intravenous infusion of thrombolytic drugs for treatment of stroke patients may improve overall patient morbidity and mortality related to acute thromboembolic disease in the central nervous system. Further clinical studies are warranted to evaluate this form of therapy.

Transluminal angioplasty of intracerebral vessels for cerebral arterial spasm: Reversal of neurological deficits after delayed treatment

We used intracerebral transluminal angioplasty to treat two episodes of symptomatic vasospasm in a patient recovering from an aneurysmal subarachnoid hemorrhage. The procedures were performed after medical therapies, intravascular volume expansion, and induced arterial hypertension failed to alleviate the patients neurological condition. The first angioplasty, confined to the right middle cerebral and distal internal carotid arteries, took place more than 30 hours after the onset of left hemiplegia. Despite the subsequent discovery of a small parietal lobe infarct, it brought about a marked improvement in left motor function and may have also limited the spread of necrotic damage. The second angioplasty was necessitated when stenotic segments of the basilar and posterior cerebral arteries caused a 24-hour decline in the patients mental status. Although delayed in relation to the onset of symptoms, it successfully reversed the patients comatose state. The use of transluminal angioplasty for vasospasm is generally limited to cases where it can be performed shortly after the onset of neurological symptoms; delaying the procedure increases the risk of hemorrhage from reperfused areas of infarction. Our experience with this patient demonstrates that delayed angioplasty can improve vascular flow to ischemic territory, even after infarction, without complications and with resultant improvement in neurological function.

Embolization of neurosurgical lesions involving the ophthalmic artery.

OBJECTIVE A number of anteriorly located cranial base and extracranial lesions receive their vascular supply wholly or in part from the ophthalmic artery, and embolization of the ophthalmic artery can be helpful in the management of these lesions, either as the primary treatment or as an adjunct to surgery. We present situations in which the embolization of lesions involving the ophthalmic artery was performed to effect a partial or total cure of the lesion. METHODS Twelve patients underwent a total of 15 embolization attempts on lesions involving the ophthalmic artery. Four patients had arteriovenous malformations of the orbit, four had dural arteriovenous fistulae, two had orbital meningiomas, one had a planum sphenoidale meningioma, and one had a juvenile nasal angiofibroma. In each case, a Tracker No. 18 microcatheter (Target Therapeutics, Inc., Fremont, CA) was navigated into the ophthalmic artery using a steerable guidewire and digital road mapping. Embolic agents included polyvinyl alcohol particles ranging from 350 to 1500 microm in diameter, 2-mm platinum microcoils, and n-butyl-cyanoacrylate. In 12 of 15 cases, lidocaine and amytal provocation tests were conducted before any attempt at embolization to assess the role of the ophthalmic artery in vision. RESULTS Embolization was successfully performed in the 14 situations in which it was attempted. Positive results of two lidocaine/amytal tests were noted. In one case, embolization was not attempted. In the other case, a larger caliber embolic agent (2-mm platinum coils) was used. A single transient decrease in visual acuity lasting 4 days was the only embolization-related complication. CONCLUSION Proper case selection, judicious use of embolic agents, and use of provocative testing can result in safe embolization of lesions supplied by the ophthalmic artery.

The role of angiogenic factor bFGF in the development of dural AVFs

SummaryPurposeDural arteriovenous fistulas (dAVFs) are known to be acquired disorders. Angiogenic stimulants, such as basic fibroblast growth factor (bFGF), may be involved in the evolution of this disorder. We examined the appearance and localization of bFGF, in human dAVF sinuses, versus a control using immunohistochemical techniques, to evaluate these qualitative differences.Patients and methodsFour human dural sinuses from dAVF patients, and one control dural sinus were removed at surgery or autopsy and used for this study. Immunohistochemistry for bFGF was performed in all five specimens to identify its appearance and localization. Immunohistochemistry for alpha smooth muscle actin, factor VIII related antigen, and macrophage (CD-68) were done in all tissues to identify the bFGF positive cell types.ResultsIn the control dural sinus, there was negative staining by bFGF immunohistochemistry. However, in all four sinuses of the dAVF patients, smooth muscle cells, endothelial cells, and meningeal cells were stained positively in various degrees by bFGF immunohistochemistry.ConclusionbFGF may be significant in the development of dAVFs, judging from its strong immunoreactivity in the sinuses of dAVF patients.