Radiation-induced cerebrovasculopathy of the distal middle cerebral artery and distal posterior cerebral artery--case report

A 15-year-old girl underwent partial removal of a pituitary adenoma followed by local irradiation of the brain with a total of 70 Gy through two lateral opposing ports. Twenty years later, she experienced frequent transient ischemic attacks with left sensory disturbance. Cerebral angiography revealed stenoses of the right distal middle cerebral artery (MCA) and the right distal posterior cerebral artery without net-like vessels. There was a severe decrease of vasoreactivity in the right hemisphere. Right superficial temporal artery (STA)-MCA anastomosis was performed. Her neurological deficits were resolved and perfusion reserve capacity had markedly improved 6 months later. We recommend STA-MCA anastomosis in such cases.     

Postoperative evaluation of EC/IC bypass surgery--long-term follow up study by donor artery compression test

Focal cerebral vascular dependency of donor arteries was evaluated in 45 patients who had undergone EC/IC bypass surgery. During EEG recording, digital compression was applied to the anastomosed donor superficial temporal artery (STA) at the preauricular region. The appearance of slow waves on the EEG recording suggests hypofunction of the local brain. In cases showing positive response to the STA compression test, we suggest that the blood supply via STA is an essential collateral route to the ischemic brain. The test was periodically repeated in the postoperative follow-up period for a mean of seven years. Eleven cases (24%) showed positive results in the STA compression test during the long-term postoperative follow-up period.     

Neurological deterioration due to cerebral hyperperfusion following carotid endarterectomy. Case report]

Recently attention has been drawn to postoperative cerebral hyperperfusion after carotid endarterectomy (CEA) associated with a preoperative state of impaired cerebral hemodynamics. Rarely postoperative neurological deficits are caused by cerebral edema due to hyperperfusion. The patient was a 65-year-old male with dysarthria and right hemiparesis. Because of the presence of severe stenosis of the left carotid artery, CEA was performed. On the 6th postoperative day, he developed severe right hemiparesis and aphasia due to cerebral edema in the subcortical region of the left cerebral hemisphere. Left carotid angiography showed normal circulation without evidence of the carotid stenosis. Later the cerebral edema and the neurological deficits gradually disappeared.     

Venous Reddening as a Possible Sign of Hyperperfusion after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis for Moyamoya Disease: Case Report

Here we report a case of moyamoya disease in which cortical veins reddened after superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis, following postoperative hyperperfusion. A 37-year-old man with moyamoya disease suffered cerebral infarction in his right hemisphere. Single photon emission computed tomography (SPECT) showed impaired cerebral blood flow (CBF) in both cerebral hemispheres. The patient underwent STA-MCA anastomosis in the right cerebral hemisphere. During operation, soon after declamping the STA, cortical veins near the anastomosis site changed its color from blue to red. This change was repeatable by clamping and declamping of the STA. Postoperative SPECT and computed tomography (CT) demonstrated increased CBF and subarachnoid hemorrhage at the anastomosis site, suggesting the occurrence of postoperative hyperperfusion. By strictly controlling the patient''s blood pressure, the syndrome resolved 1 week after the operation. We propose that the venous reddening after STA-MCA anastomosis may be a sign of postoperative hyperperfusion.     

“Reverse” Bypass Using a Naturally Formed “Bonnet” Superficial Temporal Artery in Symptomatic Common Carotid Artery Occlusion: A Case Report

We herein describe a patient with symptomatic common carotid artery occlusion who underwent a reverse superficial temporal artery (STA)-middle cerebral artery (MCA) single bypass using a naturally formed “bonnet” STA. The surgical procedure was performed without difficulty, and no further neurological deterioration was observed after surgery. In practice, this case highlights that the reverse STA-MCA bypass can be achieved safely and less invasively using a naturally formed “bonnet” STA.     

Predictor of neurologic dysfunction after elective thoracic aorta repair using selective cerebral perfusion

OBJECTIVES: This study was undertaken to determine the factors that influence postoperative neurological dysfunction after selective cerebral perfusion (SCP). DESIGN: From 1995 to August 2004, 60 patients were evaluated for the presence of cerebro-vascular disease (CVD), and then underwent thoracic aortic operations using SCP. Perioperative factors were evaluated by multivariate analyses. RESULTS: Hospital mortality rate was zero. Sixteen patients (26.7%) proved to have CVD. Permanent neurological dysfunction (PND) appeared in three patients (5.0%) and transient neurological dysfunction (TND) in two (3.3%). Univariate analysis revealed superficial temporal artery (STA) pressure during SCP (p = 0.0410) to be a significant risk factor for PND. Variables that achieved values of p < 0.2 (aortic cross-clamp time, presence of CVD, old cerebral infarction, presence of clots or atheroma) were examined with multivariate analysis and the presence of CVD (p = 0.038) and STA pressure during SCP (p = 0.032) were independent risk factors for PND. Multivariate analysis for TND did not show any risk factor. CONCLUSIONS: The presence of CVD was indicated as an independent risk factor for PND after thoracic aortic operations using SCP.     

The posterior temporal artery as the recipient in superficial temporal artery to posterior cerebral artery bypass. Technical note.

BACKGROUND: While superficial temporal artery (STA) to superior cerebellar artery (SCA) or STA to posterior cerebral artery (PCA) anastomosis has been used for rostral brain stem ischemia, it is reported not infrequently to be associated with serious complications. Although the inferior temporal artery has been proposed as a possible recipient artery for the STA, its advantage is not yet widely recognized. CASE REPORT: A 42-year-old man presented with repeated loss of vision in the left visual field. Angiography disclosed occlusion in the proximal portion of the P2 segment of the right PCA. The second case was a 68-year-old man experiencing swallowing disturbance; the bilateral vertebral arteries were markedly stenotic. Since hemodynamic insufficiency was considered to be responsible for the patients' symptoms, STA-PCA anastomosis was performed using the posterior temporal artery (PTA) as the recipient. The postoperative courses were uneventful with good patency of the bypass. TECHNIQUE: Through a horizontally extended temporal craniotomy with the base of the temporal bone sufficiently drilled away, the inferior aspect of the temporal lobe was searched for a recipient artery for the STA. The anastomosis was performed with less difficulty and at a shallower level, by 20 mm in one case and by 10 mm in the other, than had we anastomosed it to the P2 segment of the PCA. CONCLUSION: Anastomosis of the STA to the PTA is less complicated than anastomosis of the STA to the main branch of the PCA for the treatment of rostral brain stem ischemia.     

Asymptomatic carotid bruit in patients who undergo coronary artery surgery

The clinical significance of the presence of carotid bruit was evaluated in 643 patients who underwent coronary artery surgery alone or in combination with other cardiac procedures. Carotid bruit was heard in 31 patients (5%) who were neurologically asymptomatic. All of them underwent coronary artery surgery without additional carotid procedures, and none of them developed neurological deficits during the postoperative period. Of the remaining 612 patients, 18 were identified as having a history of focal neurological disorders, and 9 of them had carotid bruit. All were analyzed by means of noninvasive tests and angiography. Five underwent carotid endarterectomy prior to (2 patients) and simultaneously with (3 patients) a coronary bypass procedure. Seven patients developed neurological deficits postoperatively. Most of the deficits were not lateralized or focal but diffuse, which suggests global cerebral ischemia not related to carotid disease. Only 1 patient had proven carotid obstructive disease and underwent successful carotid thrombendarterectomy 10 days postoperatively. This study, although based on limited material, supports the hypothesis that patients with asymptomatic carotid bruit can safely undergo coronary artery surgery. In the group of patients without neurological symptomatology, postoperative neurological deficits were rarely caused by occlusive carotid disease. However, patients with asymptomatic carotid bruit should be closely followed with the goal of identifying those who are at risk of developing neurological deficits.     

Effect of extracranial-intracranial vascular bypass formation on experimental cerebral infarction in dogs (author's transl)

The middle cerebral artery was occluded at its origin via subtemporal approach by microsurgical technique in 24 dogs. In 8 of these 24 dogs, end-to-side anastomosis between the maxillary artery and a branch of the middle cerebral artery (MA-MCA anastomosis) was made 4 hours after MCA occlusion. In 5 dogs, MA-MCA anastomosis was performed under microscopic control 3 weeks after MCA occlusion. Remaining 11 dogs without shunt operation were used as control animals. All the animals were clinically observed every day until sacrifice. In the control animals, common carotid angiography was performed between the 2nd and the 5th postoperative weeks. The treated animals were studied by selective external carotid angiography 2 weeks after MA-MCA anastomosis. After sacrifice, transcarotid perfusion with 10% formalin solution was carried out and the brain was carefully removed. Each brain was additionally fixed in 10% formalin, sectioned, stained and examined pathologically. Clinical evaluation in all the control animals showed mild to severe neurological deficits or death. On the other hand, the animals with patent bypass in acute stage demonstrated no neurological deficits. Gross and microscopic evaluation of the brains showed that the permanent occlusion produced a medium or large-sized infarct in the occluded MCA territory, and the patent prompt bypass usually caused no or only microscopic infarct. In the patent delayed bypass, the size of infarct seemed smaller than that in the untreated animals. No hemorrhagic infarct was found in treated animals with either prompt or delayed bypass. In general, it seemed that the animals with patent bypass fared better than untreated animals both clinically and pathologically. The experimental data suggest that reestablishment of blood flow by extra-intracranial anastomosis, particularly within 4 hours after MCA occlusion, may lead to a significant restoration of neurological function without pathological damage of the brain.     

Reduction of ischemic brain injury in rats with normothermic and hyperthermic conditions

OBJECT: Statins have been used for induction of ischemic tolerance after cerebral ischemia. The authors have previously shown that simvastatin is protective after ischemic cerebral injury in normothermic conditions. In this study they further examined whether treatment with simvastatin can reduce ischemic brain injury in a hyperthermic condition. METHODS: Focal ischemic brain injury was induced by embolizing a preformed clot into the middle cerebral artery in rats. The authors initially examined whether treatment with simvastatin could reduce ischemic brain injury without or with hyperthermia. The infarct volume, edema, and neurological deficits were examined. They then studied whether simvastatin could reduce the perfusion deficits, damage to the blood-brain barrier (BBB), and degeneration of neurons in the ischemic injured brain. RESULTS: Simvastatin significantly reduced the infarct volume in both normothermic and hyperthermic conditions, compared with appropriate controls. Concomitantly, this treatment also significantly reduced neurological deficits and brain edema. Administration of simvastatin significantly decreased perfusion deficits, BBB permeability, and degenerated neurons. CONCLUSIONS: These studies suggest that simvastatin is an effective agent for ischemic brain injury not only in normothermic but also in hyperthermic conditions, which may be through the decrease of BBB permeability, degenerated neurons, and perfusion deficits.     

Monitoring of somatosensory evoked potentials during temporary arterial occlusion in cerebral aneurysm surgery

Somatosensory evoked potentials (SSEP) have been used during cerebral aneurysm surgery to monitor the integrity of neural pathways. The purpose of this study was to evaluate the effectiveness of SSEP monitoring as a predictor of neurological outcome during temporary arterial occlusion. In a series of 157 patients monitored, 97 patients had temporary occlusion of the feeding artery. Twenty-three patients developed a SSEP change during temporary occlusion, 15 reversible (recovery of the change after the release of occlusion), and 8 persistent (no recovery) changes. A persistent change predicted a postoperative neurological deficit in each case, whereas, of the 15 patients with reversible changes, only 5 had postoperative deficits. Seventy-four patients had no change on SSEP monitoring but 10 patients did have new neurological deficits postoperatively. The false positive rate was 43% and the false negative rate was 14%. SSEP was a better predictor of neurological deficits in patients with aneurysms of the carotid circulation than of the vertebral-basilar arteries. Despite these limitations, we find SSEP monitoring useful during temporary occlusion in cerebral aneurysm surgery.     

Comparison of middle cerebral artery trunk occlusion by silicone cylinder embolization and by trapping

The authors produced occlusion of the middle cerebral artery (MCA) trunk in dogs by two methods: silicone cylinder embolization and trapping. Comparative analyses of the clinicopathological features in these models, extending from the acute to chronic stage, were performed. Within 24 hours after embolization, the brain exhibited swelling without macroscopic infarction. Microangiograms revealed impaired filling in the deep areas of the brain with midline shift. At 4 to 7 days after embolization, the animals showed major neurological deficits, evident deep cerebral infarction, and poorly perfused areas in the deep cerebrum with prominent midline shift. At 3 to 4 weeks after embolization, the neurological deficits improved and the affected regions showed cavities or localized lesions. Microangiograms demonstrated hypervascular areas with abnormal vessels in the affected cerebrum. On the other hand, trapping of the MCA trunk produced mild neurological deficits, although there was no evidence of macroscopic lesions or impairment of filling. This study shows that silicone cylinder embolization in the MCA trunk produces a reliable and reproducible deep cerebral infarction in dogs.     

Endoscopically assisted harvesting of the superficial temporal artery: technical note

OBJECTIVE: We developed an endoscopic method for harvesting the superficial temporal artery (STA) through a small incision away from the artery. This method was used to harvest the frontal branch of the STA through an incision made along the parietal branch. METHODS: A 7-cm linear incision is made along the parietal branch of the STA. After the parietal branch has been exposed, the frontal branch is accessed through the incision with the use of an optical retractor and a 4-mm endoscope. The frontal branch is harvested subcutaneously, under endoscopic observation. Both branches of the STA are anastomosed to the middle cerebral artery via a small craniotomy made through the incision. This method was used for six patients who presented with ischemic symptoms attributable to hypoperfusion in the middle cerebral artery area. RESULTS: The frontal branch of the STA, measuring 6 to 8 cm, was harvested subcutaneously. The procedure required 30 to 60 minutes. The patency of the artery was verified with postoperative angiography. Hair loss or scalp necrosis was not noted for any patient. CONCLUSION: Our experience demonstrates that the STA can be harvested through a small incision distant from the artery. Postoperative scalp necrosis and hair loss can be avoided. This less-invasive method expands the use of the STA in revascularization surgery beyond the limitations imposed by its anatomic course.     

Risks of surgical treatment for unruptured intracranial aneurysms

The risks of surgical treatment for unruptured intracranial aneurysms, as well as the significance of evaluating cerebral blood flow (CBF), are here reported. Out of 72 patients who underwent unruptured aneurysm surgery without such complications as occlusion of the main trunk or perforating arteries, or brain contusion, and who according to CT scans, did not have new lesions related to the operations, 18 patients (25%) developed neurological deficits postoperatively. In 17 of these 18 patients, postoperative neurological deficits (frontal sign: 7, paresis: 4, and seizure: 6 cases) disappeared within 2 weeks following the operations. In the other patient, who was treated for subcortical hematoma in the left temporal lobe before aneurysm surgery, permanent speech disturbance appeared postoperatively. In the 18 patients with postoperative neurological deficits, the mean CBF value (36.2ml/100g/min) was statistically lower than that in the patients (46.2ml/100g/min) who had no postoperative neurological deficits (p less than 0.001). The rate of the patients with lower CBF values who developed postoperative neurological deficits, was statistically higher than that of patients with CBF values greater than 40ml/100g/min (p less than 0.002). In the patients with lower CBF values, common operative procedures for unruptured aneurysms such as craniotomy and mild brain retractions, may damage brain tissue. Careful perioperative management is needed for patients who undergo unruptured aneurysm surgery, because a lower CBF value may represent the degree of brain fragility.     

An episode of severely suppressed electrocerebral activity recorded by electroencephalography during endoscopic resection of a colloid cyst

Intraoperative neuromonitoring utilizing electroencephalography (EEG) is rarely performed during neuroendoscopy. The authors present a case in which this monitoring modality was used for a patient with a colloid cyst in preparation for an open craniotomy should an endoscopic approach fail. In this case, EEG serendipitously captured near-complete cessation of electrocerebral activity that occurred during intraventricular irrigation in response to ventricular collapse and resulted in no postoperative deficits. To the authors' knowledge, this is the first reported case of severe suppression of electrical activity captured by EEG during neuroendoscopy. Although they describe a transient phenomenon that resulted in no residual cognitive or neurological deficits, the importance of cautious introduction of ventricular irrigation, the need to carefully monitor intracranial pressure during neuroendoscopic procedures, and the need to pay close attention to irrigation temperature and composition should not be underestimated. Additional studies regarding the utility of EEG in alerting neurosurgeons to adverse electrical cerebral activity during neuroendoscopy are warranted.     

Progression of arteriovenous malformation in moyamoya syndrome

Summary We report a case of moyamoya disease (MMD) associated with arteriovenous malformation (AVM). The 30-year-old female patient presented with left-hemispheric transient ischaemic attacks (TIAs) involving dysphasia and right-sided hemiparesis. CT-scan and lumbar puncture showed no evidence of intracranial haemorrhage. Cerebral angiography revealed typical moyamoya vessels and occlusion of multiple cerebral arteries with consecutive collateral blood supply. Moreover, a left-parietal AVM with a diameter of approximately 2 cm was detected. An extra-intracranial arterial bypass (EIAB) connecting the left superficial temporal artery (STA) with a cortical branch of the left middle cerebral artery (MCA) was performed (STA-MCA anastomosis) and yielded subsequent resolution of the neurological deficit. Nine months post-operatively neurological deficits similar to those of the initial presentation recurred. Repeated angiography suggested comparatively increased AVM blood flow, and successful extirpation of the AVM gradually re-established almost full functional ability. However, deterioration of the neurological condition developed again. We herewith present the first European case of moyamoya disease associated with arteriovenous malformation and report the clinical course under an alternative neurosurgical treatment consisting of STA-MCA anastomosis and delayed extirpation of the AVM.     

Treatment of intracranial aneurysms by combined proximal ligation and extracranial-intracranial bypass with vein graft

Seven patients with internal carotid artery aneurysms, and one patient with a middle cerebral artery aneurysm, were managed by combining proximal ligation with an extracranial-intracranial bypass procedure. Five bypasses were done with an interposed vein graft between the external carotid artery and the distal middle cerebral artery (vein graft), and three were superficial temporal-middle cerebral artery bypasses (superficial temporal artery grafts). As demonstrated in postoperative angiograms, all eight patients had patent bypasses with nonfilling of the aneurysm. One patient developed transient dysphasia, but there were no permanent neurological deficits associated with carotid occlusion. Four patients had resolution of their neurological problems, and another three patients improved. The distribution of flow from vein grafts is more extensive than from superficial temporal artery grafts. This offers increased protection against ischemia, and increases the likelihood of internal carotid artery aneurysm thrombosis by reducing the turbulence in the distal internal carotid artery.     

Superficial temporal-middle cerebral artery bypass: clinical pre- and postoperative angiographic correlation

Between 1974 and 1982, an anastomosis between a pedicle of the superficial temporal artery (STA) and a cortical branch of the middle cerebral artery (MCA) was performed in 163 carotid systems in 157 patients for internal carotid artery occlusion in whom postoperative angiograms were available for analysis. The angiographic opacification of the arterial system was correlated with the patient's preoperative neurological function and stroke in the follow-up period. From this analysis, the following observations were made: 1) 96% of bypasses were patent; 2) 80% of bypasses achieved a high or medium MCA filling score; 3) there was hypertrophy of the STA in 70% of the cases; 4) greater bypass filling occurred in hemispheres with nonvisualized preoperative collateral circulation than in those with readily visualized collateral flow; 5) a meaningful correlation between angiographically assessed postoperative bypass function and stroke rate was not possible because only four patients suffered an ipsilateral hemispheric stroke in the 8-year follow-up period; and 6) patients who were neurologically unstable before the procedure were at greatest risk for a stroke in the follow-up period. It is apparent that objective analysis of the effectiveness of an STA-MCA bypass, or any other form of extracranial bypass, must await the development of new diagnostic studies in which high-resolution three-dimensional quantification of cerebral blood flow is possible. These studies will necessarily be correlated with preoperative and follow-up clinical data.     

Early carotid endarterectomy after cerebral infarction

The objective of the study was to review our recent experience with carotid endarterectomy performed within 30 days of completed cerebral infarction and to evaluate the role of computed tomographic (CT) scanning in the decision-making process. Twenty-seven of 302 operations (9%) were carried out during the 30-day time period. The mean interval between cerebral infarction and surgery was 14 days. Angiography revealed severe stenosis (greater than 75%) of the internal carotid artery in 19 patients. Severe stenosis with deep ulceration found in 6 patients and moderate stenosis (i.e., 50-75%) with deep ulceration was found in 2 patients. CT scans showed recent infarction in 4 patients and an old subcortical lacune in 2 patients. Twenty-two patients were neurologically stable with mild deficits and showed normal results on a CT scan performed 24 hours or more after the ischemic event. These patients underwent early cerebral angiography and carotid endarterectomy without permanent morbidity or mortality. Two patients with moderate stable neurological deficits and findings of recent infarction on CT scans had uneventful postoperative courses. Five patients who were neurologically unstable underwent surgery. The 2 patients with repeated transient ischemic attacks and normal findings on CT scans had uneventful postoperative courses. Two of the three patients with progressive neurological deficits and CT findings of recent cerebral infarction experienced extension of their infarcts after surgery. One of these patients died. Our personal experience, together with a review of previous reports, indicated that patients who have minimal residual neurological deficits and whose CT scans show normal findings are at low surgical risk, perhaps approaching that of patients with transient ischemic attacks.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intraoperative brain surface blood flow monitoring using IRIS V thermographic imaging system in patients with Moyamoya disease

Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving CBF. But little is known about the changes of intraoperative cerebral hemodynamics and its effect on postoperative neurological status including symptomatic cerebral hyperperfusion. To address this issue, we applied a novel infrared camera system (IRIS-V thermographic system) for real-time, visual monitoring of surface CBF during surgery in patients with moyamoya disease. Seven patients (8 sides, male:female= 3:4, 7-62 years old) with moyamoya disease were included in the study. After STA-MCA anastomosis, STA were occluded transiently and recanalized, and whole sequence was recorded by IRIS-V system. Correlation between clinical, radiological findings and infrared imaging were investigated. Patency of bypass was confirmed by this camera during surgery in all cases. The intraoperative imaging patterns were divided into two groups. Group A: Change of brain surface color (++) (3 cases). Group B: Change of brain surface color (-) (4 cases). Transient symptomatic hyperperfusion occurred in all patients in Group A, whereas all patients in Group B showed non-symptomatic transient focal hyperperfusion on SPECT. No patient suffered permanent neurological deterioration compared to preoperative status. Characteristic pattern of the intraoperative cerebral hemodynamics as delineated by IRIS-V could be the optimal predictor for postoperative transient symptomatic hyperperfusion after direct bypass in patients with moyamoya disease.