Fatal severe vasospasm due to rewarming following hypothermia--case report

A 37-year-old female died of cerebral vasospasm as a complication of rewarming following hypothermia therapy for severe head injury. She presented with severe consciousness disturbance and anisocoria after falling down a flight of stairs. Computed tomography (CT) revealed a right acute subdural hematoma and temporal contusion. Following surgery, mild hypothermia was started and rewarming was completed by the 11th day. Neurological examination showed no abnormalities, but intracranial pressure (ICP) suddenly increased and she manifested anisocoria on the 13th day. Repeat CT revealed a low density area in the right middle cerebral artery region and cerebral angiography showed diffuse narrowing of the main arterial trunks. A cerebrospinal fluid (CSF) sample was collected using an intraventricular ICP monitoring catheter. The CSF level of 8-hydroxy-2'-deoxyguanosine was elevated during the rewarming period, indicating substantial deoxyribonucleic acid (DNA) oxidation. She died on the 15th day due to uncontrollable ICP. Histological examination at autopsy of the narrowed artery found the waving phenomenon in the internal elastic lamina and invasion of inflammatory cells into the adventitia. These findings constitute the possible evidence that free-radical-mediated oxidative DNA damage may be important in the genesis of severe vasospasm due to rewarming following hypothermia.     

Cerebrospinal fluid flow imaging in the meningeal hemorrhage

BACKGROUND AND PURPOSES: Cerebrospinal fluid (CSF) flow oscillations are synchronized with cerebral blood flow and are also involved in the control of variations of intracranial pressure during the cardiac cycle. The aim of this study was to investigate the possible alterations of CSF flow dynamics during the acute phase of meningeal hemorrhage (MH). METHODS: Eleven patients with MH confirmed by computed tomography (CT) scan were examined by MR imaging, which comprised morphological sequences and flow dynamic sequences for quantification of CSF oscillations and cerebral blood flow rates. CSF oscillations were recorded at the cerebral aqueduct and C2-C3 subarachnoid space (SAS), where a vascular sequence was also performed to quantify artery blood flow. These results were compared to oscillations of a population of 44 control subjects and a difference of at least two standard deviation was used to define a hyperdynamic or hypodynamic appearance of CSF flow. Dilatation of the ventricular system was determined on radiographs by two neuroradiologists and a neurosurgeon. RESULTS: Only four patients presented normal ventricular CSF flow, one patient presented hypodynamic flow and five patients presented hyperdynamic flow. Five patients had normal cervical CSF flow and five patients presented hyperdynamic flow. The two patients with ventricular dilatation both presented hyperdynamic ventricular CSF flow associated with normal cervical CSF flow. One patient was excluded. CONCLUSION: Abnormal CSF flow dynamics were shown suggesting the hypothesis that bleeding increases intracranial volume and induces a reduction of cerebral compliance and an increase of intracranial pressure. The increased oscillations in the ventricular system would therefore predispose to dilatation.     

Acute cerebral ischemia after intracranial bleeding in unilateral moyamoya disease: case report

A 31-year-old male presenting with intracranial hemorrhage manifesting as deep coma and anisocoria underwent immediate emergency surgery. Three-dimensional computed tomography (CT) angiography revealed stenosis of the right middle cerebral artery (MCA) and perfusion CT immediately after the surgery suggested severe hypoperfusion in the right MCA territory. Postoperative angiography demonstrated right unilateral moyamoya disease. We predicted that brain edema and intracranial pressure (ICP) elevation occurring after the hemorrhage might result in cerebral infarction. Hyperosmotic drugs were contraindicated by dehydration. Therefore, therapeutic hypothermia was induced that controlled the ICP. We considered that the increased ICP, dehydration, vasospasm, and shrinkage of the ruptured vessel comprised the pathogenesis of acute cerebral ischemia after intracranial bleeding. Cerebral hemodynamics should be evaluated during the acute phase of cerebral hemorrhage to prevent subsequent cerebral infarction.     

Staged coronary artery bypass grafting after percutaneous angioplasty for intracranial vascular stenosis

OBJECTIVE: Cerebrovascular disease is commonly associated with coronary artery disease and is a major risk factor for cardiac surgery. Concomitant coronary artery bypass grafting and carotid endarterectomy may reduce the risk of stroke; however, this staged operation is effective only for extracranial lesions. The strategy for on-pump coronary artery bypass grafting for patients with intracranial vascular stenosis is still controversial. METHODS: The subjects were 157 consecutive candidates for coronary artery bypass grafting who underwent computed tomography and digital subtraction cerebral angiography preoperatively to check for cerebrovascular disease. Additional single-photon emission computed tomography was performed to evaluate cerebral ischemia, according to the neurologist's request. Patients with diffuse intracranial vascular stenosis impossible to treat with percutaneous transluminal angioplasty underwent off-pump coronary artery bypass grafting. Patients with a circumflex coronary artery lesion first underwent percutaneous transluminal angioplasty for cerebral vascular stenosis followed by secondary on-pump coronary artery bypass grafting. RESULTS: Three patients were selected for staged operations. Percutaneous transluminal angioplasty was performed for 4 intracranial stenotic lesions. All lesions were dilated successfully, and no complications developed during or after the procedure. All patients tolerated staged coronary artery bypass grafting and were extubated within 1 day without any mental disturbance. No further neurologic complication occurred, and computed tomography performed postoperatively revealed no significant changes. CONCLUSION: Staged on-pump coronary bypass after percutaneous transluminal angioplasty for cerebrovascular disease may reduce the risk of stroke during cardiopulmonary bypass, and it is useful especially in patients with intracranial cerebrovascular disease.     

Extracranial-intracranial bypass for reconstruction of internal carotid artery in the management of head and neck cancer

Extracranial-intracranial bypass surgery was performed prior to carotid resection in eight patients with head and neck carcinoma that involved the carotid artery near the skull base. Four patients underwent the standard one-stage extracranial-intracranial bypass procedure. A two-stage procedure was performed in the remaining four patients. The procedure first involved an anastomosis between the M3 segment of the middle cerebral artery and the superficial temporal artery, followed by a bypass between the M2 segment of the middle cerebral artery and the internal carotid artery. One of the patients who underwent the standard one-stage extracranial-intracranial bypass procedure suffered an intraoperative infarction. Despite even longer occlusion times of the M2 segment, none of the patients who underwent the two-stage bypass suffered from any serious neurologic consequences. Three of seven patients who underwent the curative operations, survived more than 4 years, however, the remaining patients died within 1 year from recurrence. Our results show that carotid artery resection yields an opportunity for cure. In extracranial-intracranial bypass surgery, the temporary occlusion of the middle cerebral artery may also induce serious ischemia; however, the two-stage extracranial-intracranial bypass procedure appears to minimize the risk.     

Missile Injuries of the Anterior Skull Base

Missile injuries of the anterior skull base usually occur during war or war-like situations. These injuries may be isolated or associated with multiple traumatic injuries. We report 23 such cases managed during military conflicts and peacekeeping operations. All were adult males. Four of these patients sustained bullet injuries; the rest were injured from shrapnel. Eighteen patients had injury to the visual apparatus with permanent blindness. Proptosis was seen in 16, cerebrospinal fluid (CSF) leak from the wound in seven, and CSF orbitorrhea in three patients. Sixteen had irreparable injury to the eye necessitating evisceration/enucleation, and two had retrobulbar optic nerve injury. Three patients were comatose [Glasgow Coma Scale (GCS) 3/15], and 14 had altered sensorium. Six patients were fully conscious. All were investigated by computed tomography (CT), which revealed injury to the eyeball and skull base, orbital fracture, frontal hematoma, contusion, and pneumocephalus. Seventeen patients underwent emergency surgery, and six patients were initially managed conservatively. Neurosurgical management consisted of making bifrontal flaps, craniotomy/craniectomy, debridement, and repair of the base with fascia lata. Reconstruction of the orbital rim was required in three cases. All were managed postoperatively with cerebral decongestants and antibiotics in anti-meningitic dosages. There was one death in the postoperative period; outcome was good in 16 and moderate in four patients. Twelve patients had retained intracranial splinters; three of these developed recurrent suppurative meningitis. Of the six patients initially managed conservatively, three were subsequently operated for CSF rhinorrhea. Gross communition, dural loss, and injury to the frontal scalp often preclude the use of pericranial repair of the skull base. Fascia lata is extremely useful for reconstruction and repair. Anterior cranial fossa injury probably carries a better prognosis; however, there is increased risk of suppurative complications due to breach of air-filled sinuses by the missile and contamination of the intradural compartment, as compared with supratentorial vault injuries not involving the orbit or paranasal sinuses. Three patients who underwent no operative procedure and remain asymptomatic are under follow-up.     

Primary empty sella syndrome in a series of 142 patients

OBJECT: The primary empty sella syndrome (ESS) represents a heterogeneous clinical picture characterized by endocrine disturbances and signs of intracranial hypertension. An increase in intracranial pressure (ICP) is proposed to be one of the involved pathogenetic factors. METHODS: The series included 142 patients who were observed during a period of 20 years. All patients underwent an ICP and cerebrospinal fluid (CSF) dynamics evaluation through the use of a lumbar constant-rate infusion test. Impairment of ICP and CSF dynamics was observed in 109 patients (76.8%). In 35 of the 36 patients affected by severe intracranial hypertension without rhinorrhea, improvement in adverse neurological symptoms was achieved after implanting a CSF shunt. Visual function, already seriously compromised before surgery, remained severely altered in one patient. In the group of 34 patients affected by rhinorrhea, CSF leakage was controlled using different surgical treatments: CSF shunt placement in 16 cases, surgical repair of the sellar floor in three, and both procedures in the remaining 13. Two patients refused any surgical treatment. CONCLUSIONS: The role of increased ICP in the pathogenesis and perpetuation of primary ESS has been confirmed. Adverse neurological signs and a CSF leak are correlated with an actual increase in ICP and are relieved after CSF shunt insertion. Cerebrospinal fluid rhinorrhea is more common than generally thought. Its resolution can be achieved using a careful diagnostic protocol and sometimes may require different surgical procedures.     

Remote medulla ablongata ventral acute subarachnoid hemorrhage following cervical spinal surgery: A case report

IntroductionThe incidence of remote intracranial hemorrhage (RICH) in patients during spinal surgery is rare and the detailed mechanism remains unclear.Presentation of caseA 55-year-old man had undergone cervical discectomy and fusion at C5–6 and C6–7 due to herniated disc and secondary spinal canal stenosis. He had severe headache 20 h postoperatively and his drain output increased from 100 to 350 mL in the second 10 h after surgery. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed and he was diagnosed with acute subarachnoid hemorrhage in the ventral medulla oblongata. The drainage tube was quickly removed. Infusion of hypertonic saline was used to reduce intracranial pressure and nimodipine prevented vasospasm around the brainstem. The patient made a gradual, satisfactory recovery with conservative treatment.DiscussionThe most likely pathomechanism leading to RICH is venous bleeding due to rapid leak of a large amount of cerebral spinal fluid (CSF) after spinal surgery. If the patient has a headache or neurological complaints after spinal surgery, immediate imaging is recommended to confirm the diagnosis. Treatment depends on the amount and location of intracranial hemorrhage.ConclusionRICH is a serious but rare complication of spinal surgery and cerebellar hemorrhage is the most common. The most important pathomechanism leading to RICH after spinal surgery is venous bleeding due to rapid leak of a large amount of CSF. Timely CT is necessary to exclude RICH. Treatment of RICH depends on the size of the intracranial hematoma and the patient’s symptoms.     

Computerized tomography angiography in patients with subarachnoid hemorrhage: from aneurysm detection to treatment without conventional angiography.

OBJECT: The purpose of this study was to determine prospectively whether and to what extent computerized tomography (CT) angiography can serve as the sole imaging method for a preoperative workup in patients with ruptured intracranial aneurysms. METHODS: During a 1-year period, all patients who presented to the authors' hospital with subarachnoid hemorrhage demonstrated by unenhanced CT scanning or lumbar puncture underwent CT angiography. Two radiologists evaluated the CT angiography source images and maximum intensity projection slabs and arrived at a consensus. They categorized the quality of the CT angiography as adequate or inadequate and classified aneurysms that were detected as definitely or possibly present. The parent artery of anterior communicating artery aneurysms was identified by asymmetrical anterior cerebral artery size and asymmetrical aneurysm location. The parent artery was indicated by the larger A1 segment in cases of asymmetrical A1 size. Only CT angiograms of adequate quality that revealed aneurysms classified as definitely present and with an unequivocal parent artery were presented to the neurosurgeons, who decided whether preoperative digital subtraction (DS) angiography should still be performed. Forty-nine of the 100 studied patients did not undergo surgery because of poor clinical condition, nonaneurysmal cause of the hemorrhage, or endovascular treatment of the ruptured aneurysm. Of the 51 patients who underwent surgery, radiologists required DS angiography in 17 patients; the imaging technique provided greater certainty in 13 instances. The neurosurgeons required DS angiography 11 times; this provided additional information in two instances. Twenty-three (45%) of the 51 patients were surgically treated successfully on the basis of CT angiography findings alone. CONCLUSIONS: Computerized tomography angiography can replace DS angiography as the preoperative neuroimaging technique in a substantial proportion of patients with ruptured intracranial aneurysms.     

Diagnostic value of CTA and MRA in intracranial traumatic aneurysms

Objective： To investigate the diagnostic value of computerized tomographic angiography （ CTA ） and magnetic resonance angiography （ MRA ） for intracranial traumatic aneurysms （TAs）. Methods： CTA and MRA of six patients with intracranial TAs verified by digital subtraction angiography （DSA） and surgery were retrospectively analysed. All patients were examined by nonenhanced computerized tomography （CT） and two by CTA. The source data were reconstructed by volume rendering （VR） and multi-planar reconstruction （MPR） from CTA. Four of them had maxhnum intensity project （MIP） from MRA. Results ： Of the six patients, a total of seven TAs were detected by CTA and MRA examinations. Five cases had only one TA and one case had two TAs. The average diameter was 2.3 cm （1.1-3.3 cm）. CTA demonstrated two TAs appeared at the cavernous segment of the internal carotid artery （ICA） and the middle cerebral artery （MCA） respectively. MCA TA was definitely and dearly demonstrated on VR images, whereas VR images failed to depict the cavernous ICA TA, which was detected on MPR images. Two TAs were found irregular saccular shape,irregular margin of parent artery and wide neck on CTA. Four MRA examinations demonstrated five TAs, including the cavernous segment ICA TAs （2 cases）, the supraclinoid segment ICA TA （1 case ）, and the cavernous segment associated with opposite side of the petrosal segment ICA TA （1 case）. In a cavernous ICA TA, MRA only revealed aneurysm body, whereas aneurysm neck and distal segment of the parent artery were not revealed. In the remaining cases, MRA clearly depicted aneurysm body and parent artery, whereas the neck was not displayed. ICA TAs showed irregular capsnle-like high signal intensity on MRA images. Four TAs exhibited irregular distal segment of the parent artery. TAs at the supraclinoid segment or MCA failed to find fracture signs on nonenhanced CT. Conclusions： Both CTA and MRA examinations are the effective non-invasive method of imageology for diagnosing intracranlal TAs, while CTA is more eligible for diagnosing TAs after nonenhanced CT has demonstrated skull base fractures.     

支架成形术治疗症状性脑供血动脉狭窄及其并发症分析

目的探讨应用颈动脉支架成形术治疗症状性脑供血动脉狭窄的安全性、临床疗效及其并发症的防治。方法对经彩色多普勒超声检查筛选,并经脑血管造影确诊的104例症状性脑供血动脉狭窄患者实施支架成形术治疗。分析围手术期及术后随访期相关并发症的发生情况。结果 1例术中出现严重血管痉挛,致手术失败,全组技术成功率99.04%(103/104)。术前平均狭窄率为82.23%,术后残余狭窄率均20.00%。术后1周内患者症状及神经功能缺损体征均有不同程度改善。24例术后3天发生心率减慢,其中20例出现血压下降;1例介入术后第9天脑出血死亡,1例术后10天靶病变部位急性血栓形成。随访2个月～3年,死亡2例,其中82例复查经颅多普勒(TCD)示血流速度正常,12例复查DSA未发现再狭窄、支架移位及缺血性脑卒中。结论颈动脉支架成形术是治疗症状性脑供血动脉狭窄较为安全、有效的方法,严格掌握适应证和熟练操作并规律服药可降低术中及术后风险。     

Normal pressure hydrocephalus: Correlation between CT and measurements of cerebrospinal fluid dynamics

Twenty-nine patients consecutively admitted for consideration of CSF diversion surgery for suspected communicating ("normal pressure") hydrocephalus underwent cranial computerized tomography (CT) and study of cerebrospinal fluid (CSF) absorption, the latter determined as resistance to outflow of CSF (Ro). From the CT the size of the ventricular system was determined by various linear measurements and ratios and the presence of periventricular lucencies (PVL) and the size of cortical sulci was noted. Except for absence of cortical sulci greater than 3 mm no CT feature was suggestive of compromised CSF absorption. On the other hand, cortical atrophy did not rule out increased resistance to CSF-outflow. Features thought of as characteristic for normal pressure hydrocephalus on CT: large ventricles as compared with the amount of cortical atrophy and presence of PVL, correlated poorly with measured high resistance values. There was no correlation between the size of the ventricular system and resistance to CSF outflow. In the diagnostic distinction between communicating ("normal pressure") hydrocephalus and cerebral atrophy (hydrocephalus ex vacuo) static CT cannot replace an actual determination of CSF outflow resistance.     

Non-traumatic cerebrospinal fluid rhinorrhea: The “Normal pressure leaks”

Summary Non-traumatic cerebrospinal fluid (CSF) rhinorrhea is an uncommon condition. 15 patients with non-traumatic CSF rhinorrhea having normal pressure leaks are presented. Metrizamide CT cisternography failed to reveal the site of the fistula in 3 patients. 11 of the 15 patients underwent surgery for closure of the fistulous communication. In 8 of them the fistula was in the anterior fossa, in one it was in the sellar floor and in two the fistula site was not seen either radiologically or at surgery. In all except the one patient with sellar floor defect an intracranial approach was used. 12 patients have been followed up for 6 months to 9 years and 10 (83%) have been cured of their rhinorrhea. The intracranial approach is preferred to an extracranial approach in the repair of anterior fossa fistulae. Conservative treatment may be effective in selected patients.Presented in part at the 34th Annual Conference of the Neurological Society of India held at Patna from 15–17 December 1985.     

Intracerebral hemorrhage following enucleation: a result of surgery or anesthesia?--A case report

Choroidal melanoma is the most common primary intraocular cancer in adults. A sixty-nine years old, hypertensive male with a choroidal melanoma underwent enucleation. After extubation he woke up confused and unconscious. An emergent computed tomographic (CT) scan demonstrated intracerebral hematoma. The underwent repeat surgery in the postoperative first hour, because of left parietotemporal intracerebral hematoma. His neurological state became worse and he died in the eighth postoperative day. Sympathetic stimulation due to extubation, causing increase in the intracranial pressure or uncontrolled hypertension, may be reasons precipitating intracranial hemorrhage. In patients, who undergo intracranial or intraorbital surgery, had risk factors of intracranial hemorrhage or showed labile blood pressure perioperatively and were confused or unconscious in the postoperatively or had delayed emergence, intracranial hematoma must be suspected.     

Management of patients with symptomatic extracranial carotid artery disease and incidental intracranial berry aneurysm

Perioperative fluctuation of blood pressure and the use of anticoagulants during carotid endarterectomy may potentiate lethal aneurysm rupture in patients who have symptomatic extracranial carotid artery occlusive disease with incidental, asymptomatic, intracranial berry aneurysms. Ten patients having this combination are described in the present study. Of five men and five women whose mean age was 63 years, nine had symptomatic carotid bifurcation atherosclerosis, one had internal carotid fibromuscular dysplasia, and all had intracranial berry aneurysms ranging from 2 to 13 mm in diameter (mean diameter 6.6 mm). In seven patients, aneurysms were greater than or equal to 6 mm in diameter. Hypertension was present in seven patients and moderately severe in five. Three of the aneurysms were located in the intracranial internal carotid artery, five in the middle cerebral artery, three in the posterior communicating artery, one in the anterior cerebral artery, and one in the superior cerebellar artery. Twelve carotid reconstructive procedures were performed without morbidity related to aneurysm rupture. These included 10 carotid endarterectomies, one of which was combined with Dacron patch angioplasty and one of which was combined with a simultaneous coronary artery bypass; one carotid artery dilatation for fibromuscular disease; and one reoperative carotid endarterectomy with patch angioplasty. Three patients had correction of hemodynamically significant lesions, two of which were proximal to ipsilateral anterior circulation aneurysms. An intraluminal shunt and heparin anticoagulation therapy were used in all patients. Despite a concerted effort to control blood pressure, the patients' perioperative blood pressures ranged from 60/30 to 240/110 mm Hg. Three patients had subsequent elective clipping of intracranial aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)     

异丙酚后处理对颅内动脉瘤夹闭术患者脑缺血再灌注时脑组织抗氧化作用的影响

目的 探讨异丙酚后处理对颅内动脉瘤夹闭术患者脑缺血再灌注时脑组织抗氧化作用的影响.方法 择期拟行颅内动脉瘤夹闭术患者30例,年龄26～64岁,体重53～73 ks,ASA Ⅰ或Ⅱ级,随机分为2组(n=15):对照组(C组)和异丙酚后处理组(P组).C组吸入0.5%～2.0%七氟烷,P组在开放载瘤动脉前吸入0.5%～2.0%七氟烷,开放载瘤动脉即刻靶控输注异丙酚至术毕,血浆靶浓度设为1.2μg/ml,同时下调七氟烷吸人浓度,维持BIS 40～60.于麻醉诱导前即刻(T_0)、阻断载瘤动脉即刻(T_1)、开放载瘤动脉即刻(T_2)、开放载瘤动脉后30min(T_3)、1 h(T_4)及术毕(T_5)时测定脑脊液压力,于T_0、T_3、T_5及术后24 h(T_6)时测定脑脊液F_2-异前列腺素(F_2-IsoPs)、α-生育酚(α-T)及γ-生育酚(γ-T)的浓度.结果 与T_0时比较,L_(4,5)时C组脑脊液压力降低,T_(3～5)时P组脑脊液压力降低,T_(3,5,6)时两组脑脊液α-T及γ-T的浓度降低,F_2-IsoPs浓度升高(P＜0.05);与C组比较,P组T_(3,4)时脑脊液压力降低,T_(3,5,6)时γ-T浓度升高,F_2-IsoPs浓度降低(P＜0.05).结论 异丙酚后处理可增强颅内动脉瘤夹闭术患者脑缺血再灌注时脑组织的抗氧化作用.     

Postoperative rupture of an untreated aneurysm on the 3rd day after subarachnoid hemorrhage surgery

A 58-year-old male presented with severe consciousness disturbance and left hemiparesis. Computed tomography (CT) revealed subarachnoid hemorrhage (SAH) and acute subdural hematoma caused by a ruptured right middle cerebral artery aneurysm. The aneurysm was clipped and the hematoma was evacuated. The patient had almost recovered without new neurological deficits on the next day. Arterial systolic blood pressure was postoperatively controlled within 120 to 150 mmHg. Continuous ventricular and cisternal drainage from the level 10 cm above the external auditory meatus was performed to drain bloody cerebrospinal fluid and prevent vasospasm. Three days after surgery, the patient suddenly lapsed into a coma. CT demonstrated diffuse SAH and bilateral intraventricular hemorrhage caused by rupture of an anterior communicating artery aneurysm. Neck clipping was performed immediately. Unfortunately, the patient died of primary damage due to SAH 3 days after the second surgery. In this case, cisternal drainage was probably important in the aneurysm rupture because of decreased intracranial pressure and change in the perianeurysm environment. Postoperative management of patients with residual untreated aneurysms must consider the possibility that cisternal drainage may result in higher transmural pressure, leading to rupture of the untreated aneurysms.     

Cerebral autoregulation among patients with symptoms of hydrocephalus

OBJECTIVE: To study the relationship between the resistance to cerebrospinal fluid (CSF) outflow and cerebral autoregulation. METHODS: We examined 35 patients who presented with ventricular dilation and clinical symptoms of communicating hydrocephalus. For all of these patients, CSF compensatory reserve was investigated by using a computerized infusion test, with simultaneous recording of blood flow velocity wave forms (by using transcranial Doppler ultrasonography) and arterial blood pressure (with a Finapress finger cuff). The resistance to CSF outflow was calculated as the absolute increase in intracranial pressure (interpolated over vasogenic waves) divided by the infusion rate (1.5 ml/min in most cases). The index of autoregulation was assessed as a correlation coefficient (moving time window of 5 min) between slow waves (with periods of 20 s to 2 min) in mean blood flow velocity and cerebral perfusion pressure. RESULTS: The mean intracranial pressure increased during the test, from 6 mm Hg (standard deviation, 6 mm Hg) to 20 mm Hg (standard deviation, 10 mm Hg) (P < 0.0001). The index of autoregulation was significantly correlated with the resistance to CSF outflow (r = -0.41, P < 0.03), indicating better autoregulation with greater resistance to CSF outflow. CONCLUSION: Patients presenting with ventricular dilation may exhibit either decreased (atrophy) or increased (normal-pressure hydrocephalus) resistance to CSF outflow. Increased resistance is correlated with preserved autoregulation. Patients with low resistance, suggesting brain atrophy, more often have disturbed autoregulation in the middle cerebral artery territory, as assessed by transcranial Doppler ultrasonography.     

Management of complex intracranial aneurysms with bypass surgery: a technique application and experience in 93 patients

Despite advances in microsurgery and the development of new endovascular techniques, the treatment of complex intracranial aneurysms remains a daunting challenge for neurosurgeons. In the present study, we retrospectively reviewed our experience of bypass surgery in the treatment of 93 cases of complex intracranial aneurysms. A series of 93 consecutive cases of complex intracranial aneurysms were treated with bypass surgery between April 2004 and July 2013. Radial artery (RA) grafts were used in 58 cases, saphenous vein (SV) grafts in 16 cases, and occipital artery (OA) grafts in 6 cases, while the remaining 13 cases were managed with superficial temporal artery (STA) grafts. In this series, the aneurysms were excised after trapping in 32 cases with mass effect and neural compression. Proximal occlusion of the parent artery was performed in 22 cases of fusiform or giant dissecting aneurysms with subsequent retrograde flow to avoid compromise of the perforators nearby. Trapping was performed after bypass surgery in the remaining 39 cases. Postoperative angiographies were performed in 91 patients and patency of the bypass graft and obliteration of the aneurysms were confirmed in 89 patients. Patency of the bypass could not be confirmed in the remaining two patients, of which one presented with cerebral infarction due to graft occlusion, and the other remained asymptomatic. Within 1 month after surgery, 88 patients had good outcome, four patients needed assistance for daily living, and one death occurred due to brainstem infarction. In 77 patients with a mean follow-up of 3.0 years, 72 patients had good outcome, 4 patients needed assistance for daily living, and 1 death occurred unrelated to surgery. Complex intracranial aneurysms present unique therapeutic challenges that require thorough surgical planning, individualized treatment strategies, and refined neurovascular techniques for successful outcome. Proper use of bypass surgery is imperative in preserving the parent artery and its major perforators. The internal maxillary artery, used as a donor in a bypass, is an effective method due to its shorter distance from the recipient vessels and relatively large diameter with resulting higher flow rate.     

One patent intracranial collateral predicts tolerance of flow reversal during carotid angioplasty and stenting

Internal carotid artery (ICA) flow reversal is an effective means of cerebral protection during carotid stenting. Its main limitation is that in the absence of adequate collateral flow it may not be tolerated by the patient. The purpose of this study was to determine if preoperative identification of intracranial collaterals with computerized tomographic (CTA) or magnetic resonance (MRA) angiography can predict adequate collateral flow and neurological tolerance of ICA flow reversal for embolic protection. This was a study of patients undergoing transcervical carotid angioplasty and stenting. Neuroprotection was established by ICA flow reversal. All patients underwent preoperative cervical and cerebral noninvasive angiography with CTA or MRA and had at least one patent intracranial collateral. Mean carotid artery back pressure was measured. Neurological changes during carotid clamping and flow reversal were continuously monitored with electroencephalography (EEG). Thirty-seven patients with at least one patent intracranial collateral on brain imaging with CTA or MRA were included. Mean carotid artery back pressure was 58 mm Hg. All procedures were technically successful. No EEG changes were present with common carotid artery occlusion and ICA flow reversal. One patent intracranial collateral provides sufficient cerebral perfusion to perform carotid occlusion and flow reversal with absence of EEG changes. Continued progress in noninvasive imaging modalities is becoming increasingly helpful in our understanding of cerebral physiology and selection of patients for invasive carotid procedures.