Cerebral Artery Bifurcation Research Articles

Deviation from optimal vascular caliber control at middle cerebral artery bifurcations harboring aneurysms

Cerebral aneurysms form preferentially at arterial bifurcations. The vascular optimality principle (VOP) decrees that minimal energy loss across bifurcations requires optimal caliber control between radii of parent (r0) and daughter branches (r1 and r2): r0n=r1n+r2n, with n approximating three. VOP entails constant wall shear stress (WSS), an endothelial phenotype regulator. We sought to determine if caliber control is maintained in aneurysmal intracranial bifurcations. Three-dimensional rotational angiographic volumes of 159 middle cerebral artery (MCA) bifurcations (62 aneurysmal) were processed using 3D gradient edge-detection filtering, enabling threshold-insensitive radius measurement. Radius ratio (RR)=r03/(r13+r23) and estimated junction exponent (n) were compared between aneurysmal and non-aneurysmal bifurcations using Student t-test and Wilcoxon rank-sum analysis. The results show that non-aneurysmal bifurcations display optimal caliber control with mean RR of 1.05 and median n of 2.84. In contrast, aneurysmal bifurcations had significantly lower RR (0.76, p<.0001) and higher n (4.28, p<.0001). Unexpectedly, 37% of aneurysmal bifurcations revealed a daughter branch larger than its parent vessel, an absolute violation of optimality, not witnessed in non-aneurysmal bifurcations. The aneurysms originated more often off the smaller daughter (52%) vs. larger daughter branch (16%). Aneurysm size was not statistically correlated to RR or n. Aneurysmal males showed higher deviation from VOP. Non-aneurysmal MCA bifurcations contralateral to aneurysmal ones showed optimal caliber control. Aneurysmal bifurcations, in contrast to non-aneurysmal counterparts, disobey the VOP and may exhibit dysregulation in WSS-mediated caliber control. The mechanism of this focal divergence from optimality may underlie aneurysm pathogenesis and requires further study.

Widening and high inclination of the middle cerebral artery bifurcation are associated with presence of aneurysms.

The middle cerebral artery (MCA) bifurcation is a preferred site for aneurysm formation. Wider bifurcation angles have been correlated with increased risk of aneurysm formation. We hypothesized a link between the presence of MCA aneurysms and the angle morphology of the bifurcation. Three-dimensional rotational angiography volumes of 146 MCA bifurcations (62 aneurysmal) were evaluated for angle morphology: parent-daughter angles (larger daughter Ф1, smaller daughter Ф2), bifurcation angle (Ф1+Ф2), and inclination angle (γ) between the parent vessel axis and the plane determined by daughter vessel axes. Statistics were evaluated using Wilcoxon rank-sum analysis and area under the receiver operator characteristic curve. Aneurysmal bifurcations had wider inclination angle γ (median 57.8° versus 15.4°; P<0.0001). Seventy-five percent of aneurysmal MCAs had γ >10°, compared with 25% nonaneurysmal. Ф1 and Ф2, but especially Ф1+Ф2, were significantly larger in aneurysmal bifurcations (median 171.3° versus 98.1°; P<0.0001). Sixty-seven percent of aneurysmal bifurcations had Ф1+Ф2 >161°, compared with 0% nonaneurysmal MCAs. An optimal threshold of 140° was established for Ф1+Ф2 (area under the curve, 0.98). Sixty-eight percent of aneurysms originated off the daughter branches. Seventy-six percent of them originated off the branch with the largest branching angle, specifically if this was the smaller daughter branch. Wider Ф1+Ф2 correlated with aneurysm neck width, but not dome size. MCA bifurcations harboring aneurysms have significantly larger branching angles and more often originate off the branch with the largest angle. Wider inclination angle is strongly correlated with aneurysm presence, a novel finding. The results point to altered wall shear stress regulation as a possible factor in aneurysm development and progression.

Comparison of 64 Dedector Cranial CT Angiography with Intra-Arterial DSA For Detection of Intracranial Aneurysms

The purpose of our study was to compare findings of 64 detector cranial computed tomographic angiography (CTA) and convention al digital subtraction angiography (DSA) mainly in patients with acute subarachnoid hemorrhage (SAH) headache and diplopia. Between March 2007 and May 2009, 65 consecutive patients were admitted with clinical symptoms and signs of intracranial aneurysm. 44 of 67 detected aneurysms were confirmed during surgery or endovascular embolization. DSA was performed in the 3 days after CTA. CT angiograms and conventional angiographies were studied by two radiologists, who performed aneurysm detection and characterisation of morphological features. Using CTA and DSA, we detected 67 aneurysms in 50 patients. 15 patients did not have any aneurysms in both DSA and CTA. There was no difference between the two modalities in the number of the detected aneurysms. But two aneurysms were falsely located before surgery with CTA. They were located in posterior communicating artery (PcoA) but, had been thought to be located at the internal carotid artery supraclinoid segment at CTA. CTA has an equal sensitivity as DSA in the detection of intracranial aneurysms. It has 100% detection rate in anterior communicating artery and middle cerebral artery bifurcation aneurysms, but aneurysms at some locations, like the ones at PcoA, were hard to detect with CTA. DSA preserves its diagnostic value for detection of posterior circulation aneurysms.

Y-stent-assisted coil embolization of cerebral aneurysms.

Y-stent-assisted coiling is a technique used by neuroendovascular surgeons to treat complex, wide-necked, bifurcation aneurysms in locations such as basilar tip and middle cerebral artery bifurcation. Several recent studies have demonstrated low complication rate and favorable clinical and angiographic outcomes. The Y-stent technique is illustrated here in detail and the intraoperative nuances are also discussed to minimize potential complications associated with technique. The video can be found here: http://youtu.be/77pEmqx_fyQ .

Clip reconstruction of a large right MCA bifurcation aneurysm. Case report

Abstract We report a case of complex large middle cerebral artery (MCA) bifurcation aneurysm that ruptured during dissection from the very adherent MCA branches but was successfully clipped and the MCA bifurcation reconstructed using 4 Yasargill clips. Through a right pterional craniotomy the sylvian fissure was largely opened as to allow enough workspace for clipping the aneurysm and placing a temporary clip on M1. The pacient recovered very well after surgery and was discharged after 1 week with no neurological deficit. Complex MCA bifurcation aneurysms can be safely reconstructed using regular clips, without the need of using fenestrated clips or complex by-pass procedures.

Reply to the Comment on the Article “Selective-Targeted Extra-Intracranial Bypass Surgery in Complex Middle Cerebral Artery Aneurysms

Bypass surgery plays a very important role in the management of complex middle cerebral artery (MCA) aneurysms not amenable to selective clipping, coiling, or other endovascular procedures. The goal of a bypass is the preservation of blood flow in the territory fed by the vessel that needs to be occluded for final aneurysm treatment.1 Identification of the correct bypass recipient could be obtained by microsurgical dissection of both the perianeurysmal angioanatomy and the sylvian fissure.2 When dissection of the sylvian fissure is considered at risk or when a superficial cortical recipient artery (namely an M4 segment of the MCA) is preferred as the recipient, it is very important that the cortical recipient artery represents a distal branch of the trapped vessel. Angioanatomic landmarks and neuroimaging, neuronavigation, and stereotactic modalities represent useful tools3,4 for identifying the correct recipient; however, the risk of revascularization into a wrong territory still exists, with possible subsequent severe ischemic effects.1,3 We recently reported the feasibility and efficiency of a technique for selective-targeted revascularization, namely for the identification and targeting of the cortical recipient in extracranial-to-intracranial bypass surgery for the treatment of complex MCA aneurysms.1 The technique is based on the use of microscope-integrated near-infrared indocyanine green video angiography. We have reported our clinical experience in 7 consecutive patients treated for complex MCA aneurysms. This technique allowed the correct identification of the cortical recipient arteries (cortical branches of the trapped MCA segment) in all patients and eliminated the risk of erroneous revascularization of uninvolved territories. Patients underwent successful treatment of their aneurysm, including a cortical bypass; no ischemic complications were reported, and a favorable clinical outcome was achieved in all patients (The modified Rankin Scale score at follow-up was less than or equal to the preoperative modified Rankin Scale score). This technique can be applied in the treatment of both proximal and distal complex MCA aneurysms.1 We thank Dr Andreas Gruber (Vienna, Austria), Drs Duke Samson and Kim Rickert (Dallas, Texas), and Dr Laligam N. Sekhar (Seattle, Washington) for their comments on and contributions to our article.1 From part of Dr Sekhar’s comment, we realized that the illustrations of the case example 2 (see the original publication) may have been somewhat misleading. Dr Sekhar stated that “in the case example 2, we decided to accept the sacrifice of the anterior temporal artery, even with the knowledge that it will lead to infarction of that portion of the brain.” In fact, we did not sacrifice the anterior temporal artery. We only occluded it temporarily to perform a provocative indocyanine green video angiography to avoid the selection of a cortical recipient representing a branch of the anterior temporal artery itself. This step was useful for extra verification and represents an application of the technique to identify “uninvolved” cortical arteries. To better illustrate the treatment strategy applied in this case, we supply this letter with a new schematic drawing (Figure).FIGURE: A, drawing illustrating the partially thrombosed giant middle cerebral artery (MCA; M1) bifurcation aneurysm and the perianeurysmal angioanatomy. B, the same drawing after placement of a temporary clip on the anterior temporal artery to perform a provocative indocyanine green video angiography to identify “uninvolved” cortical arteries (namely perisylvian fissure cortical arteries not representing distal branches of the artery that need to be occluded for the final aneurysmal treatment). C, the same drawing after removal of the temporary clip on the anterior temporal artery and placement of a temporary clip on the M2 segment of the MCA to perform a provocative indocyanine green video angiography to identify the correct cortical recipient (a cortical artery representing a branch of the artery that needs to be occluded for the final aneurysmal exclusion). D, the same drawing illustrating the permanent clips used for final aneurysm exclusion and the role of the bypass in revascularizing vessels coming from the permanently occluded aneurysmal branch. The anterior temporal artery was preserved.Disclosure The authors have no personal financial or institutional interest in any of the drugs, materials, or devices described in this article. Acknowledgment We thank Peter Roth (Department of Neurosurgery, University Hospital Zurich, Zurich, Switzerland) for the drawings in the Figure.

Intracerebral aneurysmal bleed presenting as acute subdural haemorrhage

Acute subdural haemorrhage (aSDH) secondary to an aneurysmal bleed is a surgical emergency that requires urgent decision making. Major dilemmas are whether preoperative diagnostic studies should precede surgery and whether obliteration of the aneurysm should be performed during haematoma evacuation or as a separate delayed intervention after resuscitation. We successfully operated on a 44-year-old patient with aneurysmal aSDH, and discuss the challenges involved with such patients. Case report A 44-year-old man was brought unconscious to hospital by paramedics. Immediate family members or friends were not available to give a reliable history. On admission his Glasgow Coma Score (GCS) was 6/15 (E1 M4 V1). His right pupil was dilated and unreactive to light and he had features of Cushing’s reflex with bradycardia and hypertension. He was immediately intubated and underwent an urgent computed tomography (CT) scan (Fig. 1), which revealed a large, right frontotemporo-parietal acute subdural haematoma with effacement of basal cisterns and evidence of mass effect and midline shift. The scan also showed thick blood in the right sylvian fissure and a thrombus in the superior temporal gyrus on the right side. Because of features of uncal herniation, an emergency craniotomy was performed immediately. On draining the aSDH, the brain became lax and pulsatile. The sylvian fissure was thereafter opened proximal to distal. The arachnoid membrane across the sylvian fissure could clearly be seen in the proximal fissure, but distally, over the aneurysm, it was obliterated by the thick thrombus surrounding the fundus of a large bi-lobed aneurysm at the middle cerebral artery (MCA) bifurcation. The thrombi were carefully removed and the aneurysm neck was dissected out and clipped using a large curved Yasargil clip. Postoperatively he was ventilated for 24 hours and then gradually weaned off the ventilator. His postoperative recovery was slow but steady. On last followup six months after surgery he had made significant recovery with a modified Rankin score of 2. He was independent for activities of daily living but had not yet resumed his earlier vocation.

Trapping of Endovascular Microguidewire: A Rare and Serious Complication During Therapeutic Microcatheterization for Cerebrovascular Disease

A 71-year-old woman was admitted for endovascular treatment of a small but wide-necked aneurysm at the right middle cerebral artery (MCA) bifurcation. Our plan was to first apply a microcatheter protective technique, reserving stent protection as a fall-back strategy. Under general anesthesia, a 6F guiding catheter was thus advanced to the cervical segment of right internal carotid artery, followed by passage of an Excelsior SL-10 microcatheter (Boston Scientific, Natick, MA) into the superior division of MCA. At this point, a microcatheter of larger caliber (Prowler Select Plus, Codman, Miami Lakes, FL) was to replace the Excelsior SL-10, relying on a long microguidewire (Transend 300 Floppy, Boston Scientific) to effect the exchange. Unfortunately, the microwire became trapped during the exchange process and was impossible to readily advance or retrieve. Attempts at forcible withdrawal retracted the entire right cerebral artery, without releasing the wire. Furthermore, the M1 trunk was not visualized on angiography, and all tension on the microwire was released. This maneuver restored main MCA flow, but the superior division of MCA was still not visualized. We assumed that hyperacute vasospasm had intervened due to arterial perforation by the microguidewire. Introduction

Three-Dimensional Microsurgical Anatomy of the Choroid Plexus Using the Volume Rendering Technique.

The choroid plexus (CP) is a specific anatomical structure producing cerebrospinal fluid into the ventricular space. The three-dimensional anatomical structure of the choroid plexus located within the lateral ventricle may be evaluated by using the three dimensional volume rendering technique (3D-VRT) from acquired two-dimensional contrast enhanced computerized tomographic images. The raw data of Three-dimensional Computerized Tomography Angiography (3D-CTA) were transferred into the computer and recorded in a software program. These images were evaluated in terms of anatomical shape, borders, extensions length and dimensions. The patient group consisted of 57 (27 female and 30 male) patients. The mean age of the patients was 55±9 years. In male individuals, the distance of the superior tip from Frazier's point was 7.96±0.71 centimeters at the right side. In males, the distance of the inferior tip of the CP was estimated as 1.93±0.26 centimeters posterior-lateral from the anterior clinoid process, 1.64±0.23 centimeters posterior-lateral from the bifurcation of internal carotid artery, and 2.86±0.23 centimeters posterior-medial from the bifurcation of middle cerebral artery on the right side. The results of this study showed us that this technique could be used in the three-dimensional evaluation of some anatomical structures such as the choroid plexus.

Incidental Saccular Aneurysms on Head MR Angiography: 5 Years' Experience at a Single Large-Volume Center.

Background and PurposeThe diagnostic accuracy for unruptured intracranial aneurysms has increased, and incidental asymptomatic aneurysms have come to represent a substantial clinical burden because of their controversial natural history. However, their prevalence may be attributable to variations in evaluation methods and demographics. We therefore describe the prevalence and magnetic resonance angiography (MRA) findings of incidental intracranial saccular aneurysms over a 5-year period at a single large-volume center.MethodsMRA images from 18,237 patients obtained between January 2001 and December 2005 were retrieved from the radiology report database. Patients diagnosed with incidental intracranial saccular aneurysms were identified and their MRA data were reviewed. Imaging and clinical follow-up data were evaluated.ResultsDuring the study period, 366 incidental intracranial saccular aneurysms were identified in 330 patients (prevalence, 1.8%; 95% confidence interval, 1.63%-2.01%; 115 men and 215 women; age range, 22-82 years; median age, 63 years). The prevalence was higher in women (215/8,112) than in men (115/10,125; P=0.02). The prevalence increased with age in women (P<0.01), but not in men (P=0.30). Aneurysm size ranged from 1.5 mm to 13 mm, with a median size of 4 mm. The most common location was the bifurcation of the middle cerebral artery (131/366; 35.8%).ConclusionsOur real world experience indicated a slightly lower overall prevalence of incidental intracranial saccular aneurysms than previously reported. The prevalence increased with age in women but not in men.

A new measure for monitoring intraoperative somatosensory evoked potentials.

ObjectiveTo propose a new measure for effective monitoring of intraoperative somatosensory evoked potentials (SEP) and to validate the feasibility of this measure for evoked potentials (EP) and single trials with a retrospective data analysis study.MethodsThe proposed new measure (hereafter, a slope-measure) was defined as the relative slope of the amplitude and latency at each EP peak compared to the baseline value, which is sensitive to the change in the amplitude and latency simultaneously. We used the slope-measure for EP and single trials and compared the significant change detection time with that of the conventional peak-to-peak method. When applied to single trials, each single trial signal was processed with optimal filters before using the slope-measure. In this retrospective data analysis, 7 patients who underwent cerebral aneurysm clipping surgery for unruptured aneurysm middle cerebral artery (MCA) bifurcation were included.ResultsWe found that this simple slope-measure has a detection time that is as early or earlier than that of the conventional method; furthermore, using the slope-measure in optimally filtered single trials provides warning signs earlier than that of the conventional method during MCA clipping surgery.ConclusionOur results have confirmed the feasibility of the slope-measure for intraoperative SEP monitoring. This is a novel study that provides a useful measure for either EP or single trials in intraoperative SEP monitoring.

The Contribution of Three-Dimensional Computerized Tomographic Angiography in the Head Positioning of the Patients with Middle Cerebral Artery Aneurysms.

Surgical intervention is a gold standard technique for ruptured and unruptured middle cerebral artery bifurcation aneurysm. Before surgical intervention it is necessary to know the three-dimensional shape, surgical position, projection and position of the aneurysm and the course of the parent artery. In a demonstrative case with middle cerebral artery aneurysm, using the OsiriX MD image processing software for DICOM images, it was demonstrated the position of the aneurysm neck, the projection of the aneurysm and the course of the M1 segment in relation with dynamic rotation and extension of the head. These dynamic videographic neuroradiological images may enhance the surgical anatomic perspective of the surgeon before the surgical intervention.

Endovascular coil embolization after clipping: endovascular treatment of incompletely clipped or recurred cerebral aneurysms.

ObjectiveThe presence of a cerebral aneurysm remnant after surgical clipping is associated with a risk of regrowth or rupture. For these recurred aneurysms, coil embolization can be considered as a treatment option. We retrospectively reviewed cases of ruptured or regrown aneurysms after clipping treated by endovascular coil embolization.Materials and MethodsWe conducted a retrospective review of patients with ruptured or recurred aneurysm after clipping, who underwent coil embolization between January 1995 and December 2013. We evaluated clinical information and the outcomes of these cases.ResultsEight patients were treated by endovascular coil embolization after surgical clipping. Six aneurysms were located in the anterior communicating artery, one in the posterior communicating artery, and one in the middle cerebral artery bifurcation. All patients were initially treated by surgical clipping because of a ruptured aneurysm. Aneurysm recurrence at the initial clipping site was detected in all cases. The median interval from initial to second presentation was 42 months. In four patients, aneurysms were detected before rupture and the four remaining patients presented with recurrent subarachnoid hemorrhage. All patients were treated by coil embolization and showed successful occlusion of aneurysms without complications.ConclusionEndovascular coil embolization can be a safe and successful treatment option for recurred aneurysms after clipping.

Endovascular and surgical options for ruptured middle cerebral artery aneurysms: review of the literature.

Middle cerebral artery (MCA) aneurysms are common entities, and those of the bifurcation are the most frequently encountered sublocation of MCA aneurysm. MCA bifurcation (MBIF) aneurysms commonly present with subarachnoid hemorrhage (SAH), are devastating, and are often lethal. At the present time, the treatment of ruptured MBIF aneurysms entails either endovascular or open microneurosurgical methods to permanently secure the aneurysm(s). The purpose of this report is to review the current available data regarding the relative superiority of endovascular versus open microneurosurgical clipping for the treatment of ruptured middle cerebral artery bifurcation aneurysms.

Waffle Y technique: pCONus for tandem bifurcation aneurysms of the middle cerebral artery

Broad based bifurcation aneurysms are challenging. Various endovascular techniques aim at stabilizing the coil package in the aneurysm. Among these, the waffle cone technique provides a viable alternative to Y...

Middle Cerebral Artery Bifurcation Aneurysms

Changing landscapes in neurosurgical training and increasing use of endovascular therapy have led to decreasing exposure in open cerebrovascular neurosurgery. To ensure the effective transition of medical students into competent practitioners, new training paradigms must be developed. Using principles of pattern recognition, we created a classification scheme for middle cerebral artery (MCA) bifurcation aneurysms that allows their categorization into a small number of shape pattern groups. Angiographic data from patients with MCA aneurysms between 1995 and 2012 were used to construct 3-dimensional models. Models were then analyzed and compared objectively by assessing the relationship between the aneurysm sac, parent vessel, and branch vessels. Aneurysms were then grouped on the basis of the similarity of their shape patterns in such a way that the in-class similarities were maximized while the total number of categories was minimized. For each category, a proposed clip strategy was developed. From the analysis of 61 MCA bifurcation aneurysms, 4 shape pattern categories were created that allowed the classification of 56 aneurysms (91.8%). The number of aneurysms allotted to each shape cluster was 10 (16.4%) in category 1, 24 (39.3%) in category 2, 7 (11.5%) in category 3, and 15 (24.6%) in category 4. This study demonstrates that through the use of anatomic visual cues, MCA bifurcation aneurysms can be grouped into a small number of shape patterns with an associated clip solution. Implementing these principles within current neurosurgery training paradigms can provide a tool that allows more efficient transition from novice to cerebrovascular expert.

Use of Buddy Wire to Facilitate Y-Configured Stent Placement in Middle Cerebral Artery Bifurcation Aneurysms With Daughter Branches Arising From the Sac

Endovascular treatment of geometrically complex bifurcation aneurysms using a standard Y-configured stenting technique might be extremely difficult, particularly in aneurysms with daughter branches that acutely arise from the aneurysm sac itself. In those cases, deployment of the second stent through interstices of the first stent could be troublesome because of untoward angular changes in the vascular bifurcation prompted by angular changes resulting from placement of the first stent. Here, we describe a novel application of the buddy wire technique to facilitate Y-configured stenting in middle cerebral artery (MCA) bifurcation aneurysms with unfavorable anatomic configuration. A 60-year-old man with a left-sided MCA bifurcation aneurysm was treated using the buddy wire technique. In addition to the standard Y-configured stenting procedure, we also inserted a 0.014-inch exchange microguidewire into the superior daughter branch, which more acutely emanated from the sac, to attain a favorable bifurcation configuration before deployment of the stents in the Y configuration. The new technique was successful, and the postprocedural course of the treatment was uneventful. Use of a buddy wire in MCA bifurcation aneurysms with unfavorable anatomic configurations may be a promising method to facilitate Y-configured stent placement.

Regulation of pre-natal circle of Willis assembly by vascular smooth muscle Notch signaling

The circle of Willis (cW) is a major arterial collateral structure interconnecting hemispheric circulation within the brain, and in humans, anatomical variation of the cW is linked to stroke risk. Our prior studies on adult mice deficient in vascular smooth muscle cell (vSMC) Notch signaling revealed altered cerebroarterial maturation and patterning, including an anatomically incompetent cW similar to human variants. However, a developmental dependency on Notch signaling for cW formation in this model remained uncharacterized. Through temporospatial embryonic analyses, we now demonstrate that cW assembly is a pre-natal process highly sensitive to vSMC Notch signals, whose absence results in delayed nascent vascular plexus formation and under-development of the cW including the key anterior communicating artery (AComA) interconnecting anterior forebrain circulation. Mutant embryos additionally feature reduced vSMC coverage, non-uniform calibers and asymmetric branching at bifurcations of the major proximal cerebral arteries. At the cellular level, a notable reduction in vascular endothelial cell proliferation exists in the region of AComA assembly despite the presence of Vegfa. Furthermore, Notch signaling-deficient vSMCs in developing cerebral vessels feature reduced Pdgfrβ and Jagged1 levels and impaired proliferation. These collective findings in the embryonic brain support studies in adult animals demonstrating a reliance on intact vSMC Notch signaling for optimal neovascular responses to angiogenic stimuli. Importantly, the new data provide unique insights into the native formation of the cW and underscore a pioneering developmental role for vSMC Notch signaling in regulating temporospatial assembly of the clinically relevant cW.

Endovascular coil embolization of middle cerebral artery aneurysms of the proximal (M1) segment

Proximal middle cerebral artery (M1 segment) aneurysms have various configurations and are distinct from middle cerebral artery bifurcation aneurysms. We present the clinical and radiological results of coil embolization of the M1 segment aneurysms. From a prospective database, we retrieved the data for 59 consecutive patients harboring 60 M1 aneurysms that were treated with endovascular coil embolization from January 2006 to May 2012. We assessed the clinical outcomes of the patients and morphological outcomes of the aneurysms using the Raymond classification. The aneurysms were located on the superior wall of the M1 segment in 43 and on the inferior wall in 17. Superior-wall aneurysms were related to the frontal cortical artery and the lateral lenticulostriate perforator while inferior-wall aneurysms were to the temporal cortical artery. With coil embolization, complete aneurysmal occlusion or residual neck could be achieved in 52 aneurysms (86.7 %) and residual aneurysm in 8. The microcatheter protection technique was most commonly used for coil embolization (41.7 %) followed by single microcatheter (31.7 %), double microcatheter (23.3 %), and stent protection (3.3 %). There was no procedure-related morbidity or mortality. Follow-up angiography more than 6 months after embolization (n = 46; mean 12.4 months) demonstrated stable occlusion in 40 (87.0 %), minor recanalization in 4 (8.7 %), and major recanalization in 2 (4.3 %). One patient experienced delayed cerebral infarction without permanent neurologic deficit. Coil embolization in M1 aneurysms seems to be safe and efficacious, although it may require various technical strategies due to distinct anatomic configurations.

Terson's syndrome: neurosurgical considerations on the subject of a rare case with ophthalmological sequelae

AbstractAccording to prospective studies, vitreous hemorrhage may be diagnosed in 8%-27% of the patients with aneurysmal subarachnoid hemorrhage (SAH) (Terson's syndrome) and has been associated with a bad neurological outcome. In spite of its incidence and prognostic value, vitreous hemorrhage is underdiagnosed. We describe the case of a 48 year-old woman who was diagnosed with a SAH due to the rupture of an aneurysm of the right middle cerebral artery bifurcation that was surgically treated with minimal neurological morbidity. However, due to vitreous hemorrhage in the right eye, the patient developed visual loss that did not recovered after proper surgical treatment. In the context of the present case we take a timely review of the literature, discussing the incidence, pathophysiology, treatment and prognosis of Terson's syndrome. The reported case stresses that the natural history of Terson's syndrome is not always synonymous with good outcome. Significant visual sequelae due to vitreous hemorrhage are very rare after proper conservative or surgical treatment. The severe visual loss of this patient emphasizes the need for a systematic, early and serial ophthalmological evaluation of all patients with aneurysmal SAH.