Treatment Strategy for Cerebral Aneurysms Based on the Evidence of the Efficacy of GDC Embolization

SUMMARY

The authors reviewed 531 patients with cerebral aneurysms treated with Guglielmi detachable coils (GDCs) over 5 years to clarify both the advantages and disadvantages of embolization based on the evidence of complications by aneurysm profile. There were 52 technical complications, 25 of which resulted in unfavorable patient outcomes. Intraoperative rupture, the most serious complication exacerbating the patient's condition, occurred in 19 patients, 4 of whom expired. All of these aneurysms were very small and were mostly located in the AcomA and PICA portions. Thirteen patients encountered thromboembolic complications, 6 of whom were elderly with acute ruptured aneurysms at MCA and the tip of BA. For large or giant aneurysms manifesting the mass effect, particularly those in the ICA-C2 portion compressing the optic nerve, the saccular packing did little to ameliorate the symptoms, and subsequent surgical or endovascular trapping was needed. Therefore, saccular embolization of endovascularly difficult, very small AcomA aneurysms and large C2 aneurysm with visual symptoms should be used sparingly based on a risk-benefit assessment.

The selection and result of AVM treatment

The treatment selection for cerebral arteriovenous malformation (AVM) still is in controversy. In order to find out the best way to treat AVM, we summarized the treatment result of AVM patients in our hospital. Sixty-three AVM patients who had been treated at Nagoya University Hospital since 1988 to 1997 were studied. The patient characteristics were nearly the same as other reported series. The treatment modalities include surgery, embolization and radiosurgery. Rate of nidus disappearance was assessed in each treatment. Highest rate was observed in surgery or surgery with embolization. But new neurological deficits were seen in 37% of the patients of same group. Nidus occlusion rate was not high in radiosurgery with embolization, but low in complication rate. The result showed the importance of embolization procedure in the treatment selection of AVM. The value of functional MRI as pre-therapeutic study is high in those patients whose AVM adjacent to eloquent area.

Intra-arterial vein bypass using a vein-loaded stent system to occlude wide-necked aneurysms: an experimental study in dogs

We treated 13 experimental wide-necked aneurysms of lateral type produced in dog carotid arteries with a vein-loaded stent system consisting of an autologous vein graft, a vein-carrier stent, and two other self-expanding Z-shaped stents. The vein-loaded stent, made by connecting the autologous vein graft to the vein-carrier stent, was implanted in the common carotid artery to seal the aneurysm's orifice, after which two booster stents were deployed. The distal stent was placed to fix the distal end of the vein graft, and the proximal stent was placed at the proximal venous portion of the vein-loaded stent to reinforce its proximal end. In this manner an intra-arterial bypass was established across the aneurysm. Of 13 aneurysms seven were completely occluded, preserving the parent artery. The remaining six procedures resulted in parent artery occlusion because of failures in stent deployment. Angiograms performed in within 1 week six successfully treated dogs revealed the parent artery to be patent in four but thrombosed in two. Histological study of successful cases showed as smooth intima with slight endothelial hypertrophy and partially organised thrombus. The intraluminal features were also observed with a vascular endoscope at the time of treatment in four dogs and at the time of follow-up angiography in two. The appearances corresponded well to the macroscopic findings in the specimens. Our vein-loaded stent system offers complete closure of the orifice, which does not occur with conventional stent placement. The method is believed to show clinical promise for treating wide-necked aneurysms not curable by embolisation of the sac.

Vein-loaded stent system to occlude wide-necked aneurysms

SUMMARY

We devised a vein-loaded stent system to immediately close the aneurysmal orifice without interrupting the parent arterial flow. Ten experimental widenecked aneurysms located on canine common carotid arteries were treated with the implantation of a newly modified vein-loaded stent system. After deploying the stent, half of them were managed under administration of 50 mg of ticlopidine hydrochloride per day and the other half followed up without any anticoagulation therapy. Immediately after the stent placement, all aneurysms were completely obliterated with patency of the parent artery in the successfully implanted vessels in both groups. Follow-up angiography one week later disclosed complete occlusion of the aneurysm with patency of the parent artery in 67% (2/3) of the group with ticlopidine, while none of the group without drugs showed patency of the parent artery. The rate of patency of the parent artery was found to be improved by administration of ticlopidine, but was still lower than that of a conventional stent. Further modifications will be needed before clinical use.

Intravascular Treatment for Cerebral Aneurysms

We have treated 142 aneurysms with intrasaccular or parent artery occlusions. Selective intrasaccular occlusions were attempted on 109 cases. Total or subtotal saccular occlusion was achieved in 93 of 96 cases. Intrasaccular occlusion could not be achieved in 13 cases because of various reasons such as wide neck, branching from aneurysmal dome, difficult to catheterize, and aneurysm too small. Parent artery occlusion was attempted on 33 cases. Twenty-five patients had giant aneurysms of the internal carotid artery (ICA) at the cavernous portion. The rest of this group had dissecting or fusiform aneurysms of the vertebral artery. Parent artery occlusion was achieved in 30 cases with six ischemic symptoms. High percentage of occlusion rate and low morbidity and mortality for metallic coil embolization prove the efficacy of this endovascular treatment.

Endovascular Treatment of Excessive Spasticity from Spinal Cord Injury

We report a new treatment for excessive spasticity using an endovascular technique. A 52-year-old woman with intractable spasticity of the hip joints and abdominal muscles was treated with an injection of 70% alcohol into Adamkiewicz's artery, which destroyed the spinal cord fed by Adamkiewicz's artery and cut the reflex arcs of excessive spasticity. Immediately after the treatment a significant change was noticed in muscle tonicity of the lower extremities, and intractable spasticity disappeared. Skin necrosis and muscle damage occurred because of the alcohol that leaked into the muscle branch of the subcostal artery. However, these complications could be treated by simple necrotomy. No recurrence was observed during the follow-up period.

We believe this endovascular treatment will become a new strategy for excessive spasticity arising from spinal cord injury.

Results of 55 AVM Cases Treated by Embolization and/or Surgery

SUMMARY

In order to build a data base for future comparison, we summarized the treatment results of cerebral arteriovenous malformation (AVM) patients in our hospital. Fifty five AVM patients who had been treated at Nagoya University Hospital from 1988 to 1995 were enrolled in the study. The patient characteristics were nearly the same as other reported series. Trend of treatment modality was changing in this period and embolization was increasing in its role. Karnofsky score was used to follow the patients' clinical status. It was useful to assess pretreatment clinical status and post treatment status. The results showed the improvement of the embolization procedure.

Abnormal cerebral blood flow associated with antiphospholipid antibody syndrome--four case reports

Patients with antiphospholipid antibody syndrome manifesting as neurological symptoms (one patient with twice repeated cerebral ischemic symptoms in the left parietal and frontal lobes, and the other patient with cerebral infarction of the right temporal lobe) and non-neurological symptoms (one patient with occlusion of the superior mesenteric artery and the other patient with thrombophlebitis) underwent cerebral blood flow (CBF) studies using xenon-enhanced computed tomography. The patients with neurological symptoms had decreased CBF at the affected sites. The patients with non-neurological symptoms had decreased CBF in the left parietal and temporal lobes and/or corona radiata. Subtle preclinical thrombosis may cause chronic cerebral hypoperfusion in patients with antiphospholipid antibody syndrome.

Effect of cisternal papaverine on cerebral blood flow in patients with subarachnoid hemorrhage--three case reports

Three patients presenting with subarachnoid hemorrhage due to aneurysmal rupture underwent cerebral blood flow (CBF) measurements before and after cisternal injection of papaverine hydrochloride. One patient showed prominent increases in CBF in the frontal lobe and basal ganglia after injection of papaverine, but paradoxical decreases in the parietal lobe and corona radiata. The other two patients had poor CBF response. Dense clotting in the basal cisterns may have prevented diffusion of the agent so that only the proximal trunks of the internal carotid, anterior cerebral, and middle cerebral arteries were dilated in the former case. The dilation of proximal trunks of cerebral arteries might steal blood flow from the parietal lobe and corona radiata, where the intraparenchymal arteries were maximally dilated and cerebrovascular reserve capacity was poor.

Coagulation and fibrinolysis study after local thrombolysis of a cerebral artery with urokinase

Coagulation and fibrinolysis factors were studied in six patients after local thrombolysis with urokinase (720,000 IU). Transient abnormalities, such as prolonged prothrombin time, decreased plasminogen and alpha 2-antiplasmin activities, decreased fibrinogen, and increased fibrin degradation products were seen on the day after thrombolysis, but tended to return to the normal range on the 4th day except for one patient who suffered from disseminated intravascular coagulation. Antithrombin III activity did not change so much. Therefore, the dosage of urokinase should be as low as possible to prevent fluctuations in the coagulation and fibrinolysis system.

Subarachnoid hemorrhage of unknown origin associated with Weber-Christian disease--case report

A 58-year-old female, who had suffered from Weber-Christian disease for 26 years, presented with subarachnoid hemorrhage. Cerebral angiography showed dilatation of the basilar tip. An operation was performed in the chronic stage. The wall of dilated basilar artery was tough, but that of the right superior cerebellar artery was very thin and three small aneurysms were found on the right middle cerebral artery. Blood levels of fibrin degradation products, plasmin-alpha 2-plasmin inhibitor complex, and thrombin-antithrombin III complex were increased. The abnormality of the coagulation-fibrinolysis system and the fragility of the cerebral arteries related to Weber-Christian disease were probably the cause of the subarachnoid hemorrhage.

Hemifacial spasm in Albright's hereditary osteodystrophy with pseudopseudohypoparathyroidism and nephrogenic diabetes insipidus--case report

A 30-year-old male with Albright's hereditary osteodystrophy, pseudopseudohypoparathyroidism, and nephrogenic diabetes insipidus presented with hemifacial spasm persisting for 2 years. This association is extremely unusual. Angiography revealed markedly tortuous carotid and vertebral arteries inconsistent with his age. Neurovascular decompression of the left vertebral artery achieved only partial resolution of the spasm.

Early changes in volume and non-enhanced volume of acoustic neurinoma after stereotactic gamma-radiosurgery

The effectiveness of stereotactic gamma-radiosurgery for treating acoustic neurinoma was evaluated by measuring the volumes of the tumor, non-enhanced tumor, and cerebellar edema in 13 patients with acoustic neurinoma who were followed up for 9 to 15 months (median 12.7 mos) after treatment. The tumor volume and non-enhanced volume tended to reach a maximum after 6 months, and cerebellar edema volume after 9 months, then decreased gradually thereafter. Hearing loss tended to increase gradually, but involvement of the facial nerve was transient.

[Stereotactic radiosurgery of intracranial meningiomas]

Stereotactic radiosurgery for intracranial meningiomas was attempted using a 201-source cobalt gamma knife. Forty patients bearing 42 tumors were involved in this study. Their ages ranged from 30 to 91 years, with an average of 55.1 years. The most frequent sites of origin were the parasellar and petroclival regions. The mean tumor diameter was 27.2mm and the marginal tumor dose of radiosurgery ranged from 10 to 20Gy, depending on tumor location and size. Serial imaging studies with MRI were obtained in all 40 cases, in which minor tumor shrinkage was demonstrated in 7.9%, 40.0% and 53.3% at 6, 12 and 18 months after radiosurgery respectively. Only two tumors became enlarged after the treatment. Obvious low signal intensity on MRI, indicating central tumor necrosis, was found in 32% at 12 months and 40% at 18 months. Four large tumors over 40mm in mean diameter were treated by staged radiosurgery with intervals of 1.5 to 7 months. A similar good response was able to be obtained in all 4 cases, even though they were treated with a marginal dose less than 12Gy. Symptomatic edema occurred in 5 cases (12.5%) within 12 months and required corticosteroid therapy and hyperosmotic diuresis. In conclusion stereotactic radiosurgery has proved to be an effective and relatively safe method for the treatment of intracranial meningiomas.

Incidental white matter lesions identified on magnetic resonance images of normal Japanese individuals--correlation with age and hypertension

Incidental white matter high-intensity lesions are frequently seen on T2-weighted magnetic resonance (MR) images of the brain in older people. The incidence increases with advancing age or hypertension. Brain MR images of 59 normal individuals were examined to analyze this phenomenon. The total number of white matter high-intensity lesions correlated significantly with age (p = 0.004) or systolic blood pressure (p = 0.03). The 60- to 69-year-old group demonstrated a very close correlation of white matter lesions with systolic (p = 0.02) and diastolic blood pressure (p = 0.01), in contrast to the 50- to 59-year-old group. Hypertensive subjects in their 60s are thought to develop more white matter lesions than subjects in their 50s.

[Clinical presentations and MRI findings of angiographically occult vascular malformations]

Various clinical features as well as MRI findings of AOVM (angiographically occult vascular malformation) were studied. Amongst our patients, since January 1988, there have been 30 cases of symptomatic AOVM (20 males, 10 females) including 3 cases with multiple lesions. The age ranged from 3 to 60 years of age, with a mean of 33.4 years. The locations of symptomatic lesions were in the cerebral hemisphere (15), the thalamus (4), the brain stem (8) and in the cerebellum (3). The initial presentations of these 30 cases were either by hemorrhage (18), convulsive seizure (9) or by progressive neurological deficits (3). The initial presentation was not related to the patient's age and the size of the lesion, but apparently related to the location of AOVM. Most of the lesions in the cerebral hemisphere presented seizures, but all of the lesions in the thalamus, the brain stem and the cerebellum disclosed hemorrhage as an initial presentation. In fact it was noticed that brain stem lesions tend to cause repetitive hemorrhage in a relatively short period. AOVM lesions were clearly visualized with T2-weighted MRI images, consisting of high intensity cores with surrounding low intensity rims. Most of the symptomatic lesions were partially enhanced by Gd-DTPA with varied intensity. Dynamic changes in size and enhancement pattern on MRI were occasionally seen, usually accompanied with episodes such as hemorrhage or neurological deterioration. Although AOVMs were angiographically negative some strands indicating draining veins were observed on MRI in several cases. In contrast, none of the nonsymptomatic lesions (22 lesions) demonstrated enhancement effects with Gd-DTPA.

Magnetic resonance angiography of arteriovenous malformation in the thalamus

A comparative study of magnetic resonance angiography and conventional angiography of arteriovenous malformation in the thalamus showed that both methods clearly visualized the feeding arteries: perforating branches of the posterior cerebral artery, posterior choroidal artery and lenticulostriate artery. Draining veins such as the internal cerebral vein were also demonstrated well.

[Gamma-radiosurgery of metastatic brain tumors]

Twenty-six cases of various brain metastases were treated with Gamma-knife. Their primary sites were: lung in 13, colon in 5, breast in 2, kidney in 2, liver in 1, ovary in 1, and a malignant melanoma. The origin of one case was not verified. There were 11 single and 15 multiple metastases. In total 70 tumors were involved. Following localization with MRI and dose planning using a computer system, radiosurgery was carried out. Tumors were treated with the maximum dose between 24 and 50Gy, and with the marginal dose between 12 and 25Gy. Early follow-up results demonstrated favorable responses chiefly by tumor shrinkage, central tumor necrosis or by decreased peritumoral edema. In fact after radiosurgery, the rates of tumor shrinkage were 55.7%, 61.8% and 66.7% at 3, 6 and 9 months respectively. The tumor control rates, including regressed and stable tumors, were 98.6%, 97.1 and 85.7 at 3, 6 and 9 month intervals respectively. Meanwhile, 14 cases were neurologically improved, and another 4 showed either no perceivable change. Neurological deterioration occurred in 4 cases by progression of brain metastasis in 2 and by perifocal edema after radiosurgery. Recurrent brain metastases occurring after radiosurgery were treated with a repetition of Gamma-knife surgery in 4 cases, resulting in good tumor control. In conclusion most of the brain metastasis can be well controlled by radiosurgery for relatively long period of time.

Magnetic resonance angiography of arteriovenous malformation in the brainstem

The magnetic resonance (MR) angiography appearance of arteriovenous malformation (AVM) in the tegmentum and pons is described. The interpeduncular perforating branches of the posterior cerebral artery and median pontine branches of the basilar artery were seen more clearly by MR angiography than by conventional angiography. MR angiography was very useful for the follow-up of AVM after stereotactic radiosurgery.