Among 1328 patients of ischemic stroke undergoing cerebral angiography, there were 8 patients (0.6%) in whom the diameter of the extracranial internal carotid artery ipsilateral to the symptomatic hemisphere was less than 1 mm on the angiogram. These patients demonstrated mild to moderate hemiparesis. In 5 of 6 patients with 4-vessel angiographic study, there was entry of blood into the ischemic hemisphere via collateral channels. However, the amount of the collateral flow seemed insufficient, except for one patient. Ulcer formation was noted at the stenotic site in 5 of the 8 patients. Narrowing of the contralateral internal carotid artery was found in 5 of 7 cases in which bilateral carotid angiography was performed. Five of 8 patients underwent carotid endarterectomy, and the other three were treated conservatively. Among 5 operated cases, three alert patients improved, one alert patient showed neither improvement nor deterioration, and one somnolent patient, in whom the blood supply to the symptomatic hemisphere was only from the extremely narrow internal carotid artery, died after a large postoperative low-density area formed in the symptomatic hemisphere probably due to acute restoration of blood into the ischemic brain tissue. Among 3 conservative cases, the carotid lesion in one patient immediately changed from stenosis into occlusion and she died of tentorial herniation due to a massive infarction. One patient died of a new infarction 9 months later. In one patient the neurological deficits improved soon and she developed no ischemic symptoms in the follow-up period of 2 years. Thus, it is apparent that neurological symptoms due to hemodynamic insufficiency resulting from carotid stenosis is of rare occurrence. They seem to develop only when extreme stenosis accompanied by poor collateral circulation. Therefore, carotid endarterectomy, in general, should be aimed at the elimination of the source of embolism rather than at an improvement of cerebral blood flow. Endarterectomy for hemodynamic insufficiency can be safely carried out in patients with mild neurological deficits and is effective in prevention of further reduction of the blood flow. However, it may be followed by development of hemorrhage or swelling in the ischemic lesion if the ischemia is severe.
In this paper, an operative approach for the repair of basilar artery trunk aneurysms via Trautmann's triangular space is described and the results in five patients and reported. This approach provides a wide operative field in which to handle the aneurysm forceps more easily and affords access to 1-cm past the midline. Except for hearing loss in one patient, no patient suffered serious neurologic sequelae following basilar trunk aneurysm clipping with this approach.
Surgical results were studied in a series of 24 patients with incidental asymptomatic unruptured intracranial aneurysms. The indications for neuroradiological study resulting in incidental findings of these aneurysms were cerebral ischemia in 10 cases, ischemic heart disease in 4, headache in 4, intracerebral hemorrhage in 2, visual disturbance in 2, seizure, and hemifacial spasm in one each. In the patients with ischemic heart disease, screening cerebral angiography was performed during coronary angiography. Unruptured aneurysms identified at the time of investigation of subarachnoid hemorrhage were excluded. Twenty-four of 27 aneurysms were clipped and three were wrapped. STA-MCA anastomosis was performed at the same stage in two cases. Among these patients, there were no operative mortality. Twenty of 24 patients (83%) showed no neurological deficits or no neurological deterioration. Operative morbidity occurred in 4 cases (17%). Of these, two patients with cerebral infarction had a basilar tip aneurysm and developed new cerebral infarction in the thalamus, because perforating arteries were injured during surgery. One suffered lacunar infarction three days after surgery. Postoperative intracerebral hematoma due to brain retraction was encountered in an elderly patient. Other complications were hydrocephalus, transient oculomotor palsy, and convulsion. We concluded that the decision to surgically manage unruptured aneurysms should be made carefully, especially in patients with a basilar aneurysm and/or ischemic cerebrovascular disease. Moreover, cautious and delicate surgical manipulations are mandatory for less operative morbidity.
The authors compared Japanese and American plaque in order to clarify the histological differences between the two groups. The authors divided 72 Japanese specimens obtained by carotid endarterectomy into 2 groups. Group A contains 36 patients who had been operated on between 1976 and 1986 and Group B consisted of 36 patients who had been operated on between 1987 and 1990. The authors added, as Group C, 36 American specimens obtained between 1982 and 1986. There were no significant differences between Group A and Group B. The result indicates that the nature of pathology has not changed in the last 10 to 20 years in Japanese, although the living conditions of Japanese have changed very much in these years. There were two significant differences between Japanese and American specimens, i. e. the existence of old hemorrhage and the existence of calcifications. Intimal old hemorrhage was observed in only 6 cases of Group A and in only 8 cases of Group B, but 28 cases were observed in Group C. Calcifications were observed in only 5 cases of Group A, in only 4 cases of Group B, but in 15 cases of Group C. The result indicates that Japanese plaque occurs in the earlier stage of the disease and American plaque occurs in the advanced stage. Smooth muscle cell proliferation was observed more in American plaque. Therefore, the American plaque might be more 'tight' than Japanese plaque.
Appropriate exposure with minimal retraction of the brain is important in operating for deeply seated aneurysms. In this paper, we describe the modified pterional approach with extensive removal of the roof and lateral wall of the orbit as well as the sphenoid wing in order to expose the superior orbital fissure. In four of the six cases, which harbored an anterior communicating artery aneurysm, the orbital rim was removed for further exposure (orbitofrontotemporal craniotomy). This approach offers the following advantages: a) multidirectional view of the aneurysm; b) wide basal exposure with minimal retraction of the brain; and c) a smaller distance from the surface to the aneurysm. For a case of high positioned basilar tip aneurysm, supraorbital frontotemporal craniotomy with detachment of the zygomatic arch was carried out. After exposure of the superior orbital fissure, the anterior clinoid process was completely extirpated and the optic canal was un-roofed via the epidural space. After the arachnoid over the Sylvian fissure was dissected widely enough so that the trifurcation of the middle cerebral artery was exposed, the dura propria and the carotid ring were incised in oder to mobilize the internal carotid artery and optic nerve. With minimal retraction of the frontal lobe and internal carotid artery medially and the temporal lobe laterally, a wide operative field was gained. This approach is very useful in accessing a high positioned basilar tip aneurysm for upward viewing from below through the wide operative space.
In patients with carotid stenosis, angiography shows the degree of stenosis, but not the arterial pressure distal to the stenosis. The purpose of this study is to determine whether the arterial pressure distal to the stenotic lesion is actually decreased or not. Sixteen patients with cerebrovascular disorder were studied. Age distribution ranged from 54 to 73 years. There were ten men and six women. Of these patients, ten had cerebral infarction, three had transient ischemic attacks, one had subclavian steal syndrome, one had a small arteriovenous malformation, and one had a giant intracavernous aneurysm. All patients underwent transfemoral catheter angiography and were classified as follows: (1) no definite stenosis, six patients (control group); (2) <50% stenosis, three patients; (3) nearly 50% stenosis, six patients; (4) 90% or more stenosis, two patients. In these sixteen patients, intraluminal arterial blood pressure measurement (ABPM) was done by using the microcatheter technique. In the control group, mean arterial pressure (MAP) of the internal carotid artery was 95-97% of that of the common carotid artery. We also examined the relationship between MAP distal to the stenosis and degree of stenosis calculated from the angiographical findings. In three patients with <50% stenosis, MAP distal to the stenosis was unchanged as compared with that proximal to the stenosis. On the other hand, in two patients with 90% or more stenosis, distal MAP was significantly reduced. In six lesions of five patients with nearly 50% stenosis, reduction in MAP varied from 5% to 43%. Among these lesions, reduction in MAP was within 10% in three. Significant reduction in MAP was observed in two others. In the remaining one lesion with moderate reduction in MAP (14%), single photon emission CT demonstrated remarkable reduction in cerebral blood flow. In one patient with multiple stenotic lesions, reduction in MAP and flattened pressure wave were observed distal to the stenosis of the petrosal segment. In this patient, however, no reduction in MAP was observed distal to the stenosis of the cervical segment. From these experiences, it was concluded that ABPM is useful in determining the actual blood pressure distal to the stenotic lesion. This information is quite helpful in deciding the optimal treatment (i.e. medical treatment, bypass surgery, or endarterectomy) for the stenotic lesion of the internal carotid artery.
From the standpoint of a long-term follow-up study and our method of carotidendarterectomy (CEA), we studied factors for determinating prognoses of the patients who underwent CEA in our institute. Fifty-one patients (46 males and 5 females) underwent CEA during the past 11 years. The mean age was 64.5 and the mean follow-up period was 57.2 months. Indications for CEA were TIA, RIND, and minor stroke with carotid stenosis of over 50% and/or ulcer formation. When carotid angiogram showed stenosis of over 75%, the lesion was operated on, even if the patient did not have clinical symptoms. As intraoperative monitorings, carotid stump pressure, SEP, EEG, and carotid blood flow measurement were performed. During the operation, blood pressure was raised when it was relatively low. The Sendai-cocktail was given in order to protect the brain during temporary clipping of the carotid artery. The mean carotid stump pressure was 48mmHg. Though mild changes in SEP appeared in 21% of the patients, internal shunt was not used. The mean temporary clipping time was 36.6 minutes. There was no perioperative death, but perioperative neurological deficits appeared in 4 patients; one had a postoperative rupture of the carotid artery due to restlessness, one had carotid occlusion, and the other two showed motor weakness. In these 4 patients intraoperative monitorings showed no remarkable changes. A long-term follow-up study showed excellent condition in 23, mild disablement in 11, severe in 1, and death in 8 cases, in which 4 had heart disease. In 5 cases stroke recurred during the follow-up period, of which 3 had heart disease. From these results it was concluded that factors which worsened the postoperative courses after CEA were heart disease, failure in patient selection and poor operative technique.
Eight spinal arteriovenous malformations were treated with Tracker-18 and/or Tracker-10 minicatheter and 180 to 350μm polyvinyl alcohol particles (Ivalon). These malformations included 4 glomus, 1 juvenile, and 3 dural arteriovenous fistulas. The artificial embolization was conducted introducing the minicatheter near to the nidus or fistulas and injecting Ivalon in a flow-directed manner. During and after the intravascular treatment, these patients were carefully examined. Four patients showed marked neurological improvement just after the treatment. The other four patients, who manifested severe paraparesis before the treatment, showed either slight improvement or no change in their neurological state after the procedure. One patient with glomus-type malformations fed by intrinsic spinal cord arteries via the Adamkiwicz artery, was successfully treated preserving the important artery. On post-embolization spinal angiograms, the nidus or fistulas itself was occluded in the all patients. In summary, superselective catheterization with Tracker-18 and/or Tracker-10 minicatheter, and artificial embolization with Ivalon are paramount therapy in the management of spinal arteriovenous malformations, especially juvenile- and glomus-type malformations, because surgical intervention is thought to be difficult and embolization proximal to or at the radicular artery occasionally induces newly developed collaterals to the malformations via extra and/or intradural anastomosis.
In our clinic, we take every opportunity to conduct angiography and we try to find unruptured aneurysms for the purpose of preventing the outbreak of subarachnoid hemorrhage. The authors report the results of surgical treatment for 121 asymptomatic unruptured intracranial aneurysms. Seventy cases were incidental and fifty-one were multiple aneurysm cases which were operated on at a different time from the operation for ruptured aneurysm. There were nine documented postoperative complications (morbidity 7.4%) including seven infarctions, one intracerebral hematoma and one cranial nerve palsy by retraction. There was one death in the series (mortality 0.8%). If an aneurysm should rupture, the overall therapeutic result will not always become satisfactory even if the operation is conducted by the most skillful surgeon. Therefore, to prevent later rupture, we believe that intact aneurysm should be treated surgically under the following conditions: (1) When the patient has spent a useful and healthy life, even though now being over 70 years of age; (2) There is no uncontrollable systemic complication; (3) There is no ischemic brain disease which must be treated before aneurysm surgery. Moreover attention should be paid to the following points during operation for unruptured aneurysms: (1) identification of perforating artery around the aneurysm is important; (2) do not insist on clipping for every aneurysm; and (3) do not apply the clip over again unless absolutely necessary.
In order to evaluate the efficacy of bypass surgery, the authors analyzed the long-term results of a surgical group in comparison with those of a non-surgical group. In 42 cases in the surgical group, sixty percent of 35 patients who had neurological impairment showed improvement, especially significant improvement of cortical function such as memory disturbance and/or motor aphasia. Throughout the long-term follow-up ischemic reattacks decreased in the surgical group. On the other hand, in the non-surgical group, many patients with hemodynamic compromise suffered reattacks in the follow-up period. Regarding the finding of preoperative CT scan, bypass surgery was more effective on patients with no infarction or with watershed infarction than other types of infarction. In order to check the hemodynamic status, cerebral blood flow (CBF) was measured by 133Xe SPECT, and the Diamox test was added. In the surgical group, most patients showed a significant increase of CBF and improvement of Diamox reactivity in accordance with improvement of neurological symptoms. Although Diamox test is a useful method for evaluating the cerebral perfusion reserve and hemodynamic compromise, in some cases the decreased Diamox reactivity did not invariably reflect hemodynamic compromise. Therefore, cerebral blood volume should be measured by 99mTc-RBC SPECT to select patients for bypass surgery. Consequently, bypass surgery has a beneficial effect on patients with hemodynamic compromise, not only preventing ischemic attacks but also improving memory disturbance.
We have reported a statistical analysis of the long-term outcome of 118 patients with 142 unruptured cerebral aneurysms during the past 11-year period. Unruptured aneurysms were classified into the following 4 groups: Group 1, intact aneurysm in patient with multiple aneurysms, one of which had ruptured; Group 2, unruptured aneurysms discovered incidentally in patient with other intracranial diseases; Group 3: symptomatic unruptured aneurysm; Group 4: unruptured aneurysm screened by noninvasive method. In the 53 unoperated patients, the 5-year survival rate was 56%. During the follow-up period, 10 patients had subsequent rupture and 9 of them died. The high probability of subsequent aneurysm rupture shown by the statistical analysis of the long-term outcome was as follows: Group 3, less than 70 years old, 10-19 mm in size, VA·BA and MCA in location, and multilobed shape. The last two factors were the most important ones leading to aneurysm rupture. Among the 65 operated patients, there was no operative mortality. Transient postoperative morbidity was 3.1 percent, while permanent morbidity was 3.1 percent. The 5-year survival rate was 94%. There were no significant factors which affected the long-term outcome. Concerning the indication for surgery of unruptured aneurysm, in Group 1 and 2 at first the treatment of SAH or the underlying disease should be considered, while Group 3 aneurysms have a high probability of ruptured and require operative treatment. In Group 4, patients who have the significant variables of subsequent rupture should be treated surgically.
We have experienced seventy-three cases of incidental unruptured cerebral aneurysms. There were 33 males and 40 females. The mean age was 58. Thirty-two patients were treated by conservative means. The reasons for conservative treatment were as follows: 1) giant or surgically inaccessible aneurysms (7 patients with internal carotid artery aneurysms and 8 patients with basilar artery aneurysms); 2) partially thrombosed aneurysms (6 patients); 3) small aneurysms less than 3mm (7 patients); and 4) persisting major neurological deficits (4 patients). Six patients died from aneurysm rupture during the follow-up period, which averaged 3.9 years. Thus, the risk of fatal bleeding was approximately 4% per year. Forty-one patients harboring 54 incidental aneurysms were treated surgically. Forty-nine aneurysms were clipped, and 5 other aneurysms (3 giant and 2 vertebral artery) were treated using intravascular surgical techniques. There was no surgical mortality nor morbidity in this consecutive series of 41 patients. In conclusion, it is recommended that incidental aneurysms in the anterior circulation should be considered for surgical treatment, if the patient's clinical condition and age are favorable. For surgically high risk patients with giant aneurysms or posterior circulation aneurysms, the surgical indications will be expanded with the use of intravascular surgical techniques.