Extracranial-intracranial bypass to reduce the risk of ischemic stroke in intracranial aneurysms of the anterior cerebral circulation: a systematic review

Efficacy and Safety of Extracranial-Intracranial Bypass Surgery for Posterior Circulation Aneurysms: A Systematic Review and Single-Arm Meta-Analysis

OBJECTIVE

Treating complex posterior circulation aneurysms poses challenges, and extracranial to intracranial (EC-IC) bypass techniques are potential therapeutic options. However, the safety and efficacy of this approach for posterior circulation aneurysms remain unclear. The study's objective was to assess the safety and efficacy of EC-IC bypass in these aneurysms.

METHODS

Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we conducted a systematic review on EC-IC revascularization for posterior circulation aneurysms. Included studies had at least 4 patients and reported data on mortality, patency, complications, or clinical outcomes. Favorable clinical outcomes were defined as modified Rankin Scale below 3 or Glasgow Outcome Scale above 3, and complications were any issues related to the bypass procedure.

RESULTS

From 3036 articles reviewed, 22 studies involving 196 patients who underwent 210 EC-IC bypass procedures for posterior circulation aneurysms were selected. The median follow-up period of 14 studies was 31.66 months (6-61 months). Final follow-up indicated a high bypass patency rate of 96% [95% confidence interval [CI]: 91%-100%; I2 = 12%], with a mortality rate of 5% [95% CI: 1%-9%; I2 = 0%]. Additionally, 83% [95% CI: 70%-96%; I2 = 77%] of patients showed good outcomes at the last follow-up. Complications were observed in 40% [95% CI: 26%-55%; I2 = 80%]. Heterogeneity was associated with specific studies.

CONCLUSIONS

EC-IC bypass procedures are a viable treatment option for posterior circulation aneurysms, with high bypass patency rates and favorable clinical outcomes. However, complications, especially neurological deficits, exist. Open revascularization remains essential for neurovascular surgeons dealing with complex aneurysms.

Perioperative and long-term complications following therapeutic internal carotid artery occlusion

BACKGROUND

Parent artery occlusion (PAO) is an effective treatment for hemorrhagic diseases associated with the internal carotid artery. There are several reports of long-term cerebral infarction or the formation of de novo cerebral aneurysms following PAO.

MATERIALS AND METHODS

We retrospectively reviewed these complications in 38 patients who underwent PAO for therapeutic treatment. We investigated perioperative cerebral infarctions, long-term cerebral infarctions, and de novo aneurysms.

RESULTS

The mean age of the patients was 64.0 years, and 25 patients (65.8%) were female. The causative diseases were unruptured (n = 19; 50.0%) and ruptured (n = 8; 21.1%) aneurysms. PAO was performed after ischemic tolerance was assessed with balloon test occlusion (BTO), and BTO was performed in 34 patients, of whom 25 (73.5%) had ischemic tolerance. Twenty-six patients (68.4%) were treated with PAO alone, eight (23.5%) with low-flow bypass, and six (17.6%) with high-flow bypass. Perioperative complications occurred in five patients (13.2%): two of the 26 patients (7.7%) who underwent scheduled treatment and three of the 12 patients (25.0%) who underwent emergency treatment. One patient (2.6%) had long-term de novo aneurysm, and none developed cerebral infarction.

CONCLUSIONS

These results showed that the assessment of ischemic tolerance by performing BTO and appropriate revascularization in scheduled treatments are important to reduce perioperative and long-term cerebral infarctions. PAO must be performed with greater caution in emergency treatment.

A child who presented with cerebral infarction: Clipping combined with bypass surgery of a thrombosed giant aneurysm

Background:

Cerebral aneurysms are not common among children and most of them are presented with subarachnoid hemorrhage or mass effect. Here, we describe a rare case of a pediatric giant aneurysm presented with cerebral infarction.

Case Description:

A 38-month-old boy visited the emergency room due to left hemiparesis and left central type facial palsy. Initial magnetic resonance imaging showed acute cerebral infarction on the right basal ganglia and coronal radiata. Furthermore, a thrombosed aneurysm with a diameter of 30.57 mm at the frontal branch of the right middle cerebral artery was observed. A right pterional craniotomy with Sylvian dissection was performed. Superior and inferior divisions of the frontal branch originating from the aneurysm were identified. The superior division was cutoff from an aneurysm and clipping saving the inferior division was done. Subsequently, end-to-end anastomosis was done between a parietal branch of the superficial temporal artery and a superior division from the aneurysm. No acute complication from the operation was observed. Motor power of the left upper extremity recovered after rehabilitation, while fine motor impairment remained 6 months after the surgery.

Conclusion:

This case illustrates successful treatment of a pediatric giant aneurysm with extremely rare presentation of cerebral infarction, under a meticulous surgical plan and ad hoc modification.

Extracranial-intracranial bypass surgery for intracranial aneurysm of the anterior cerebral circulation: A systematic review and meta-analysis

Background

The safety of extracranial–intracranial (EC–IC) bypass in the management of anterior circulation intracranial aneurysms (IAs) remains to be determined. This systematic review aims to summarize the existing evidence and provide guidance for the precise management of IAs.

Data source

We constructed search strategies and comprehensively searched Pubmed, Medline, Embase, Web of science, and Cochrane library.

Methods

This systematic review was actualized according to the PRISMA statement. We evaluated study quality using the methodological index for non-randomized study (MINORS). Effect sizes were pooled using a random-effects model. Heterogeneity between studies was assessed using the I2 test. Publication bias was assessed using the Egger's test. The registration number for this systematic review is CRD42023396730.

Result

This systematic review included a total of 21 articles, involving 915 patients. Postoperative bypass patency rate was 99% (95% CI 0.98–1.00); short-term follow-up was 98% (95% CI 0.94–1.00); long-term follow-up was 95% (95% CI 0.93–0.97). The long-term follow-up occlusion rate of saphenous vein was higher than that of radial artery (OR 6.10 95% CI 1.04–35.59). Short-term surgery-related mortality was 0.3% (95% CI 0.000–0.012); long-term follow-up was 0.4% (95% CI 0.000–0.013); The proportion of patients with a score of 0–2 on the modified Rankin Scale (mRS) during long-term follow-up was 92% (95% CI 0.86–0.98). The incidence rates of long-term follow-up complications were: ischemic 3% (95% CI 0.01–0.06); hemorrhagic 1% (95% CI 0.00–0.03); neurological deficit 1% (95% CI 0.00–0.03); other 3% (95% CI 0.01–0.06).

Limitation

Most of the included studies were retrospective studies. Studies reporting preoperative status were not sufficient to demonstrate postoperative improvement. Lack of sufficient subgroup information such as aneurysm rupture status.

Conclusion

EC–IC therapy for anterior circulation IAs has a high safety profile. Higher level of evidence is still needed to support clinical decision.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023396730, identifier: CRD42023396730.

Outcomes of Arterial Bypass for Posterior Circulation Atherosclerosis: A Case Series

BACKGROUND

Extracranial-intracranial bypass is an effective treatment option for moyamoya disease and in well-selected cases of anterior circulation intracranial atherosclerotic disease; however, the effectiveness of bypass is less evident in posterior circulation atherosclerosis. Updated surgical techniques and clinical guidelines necessitate modern appraisal of arterial bypass for symptomatic patients with posterior circulation atherosclerotic disease who are refractory to medical management.

OBJECTIVE

To evaluate the complications, graft patency, and postoperative outcomes of arterial bypass for posterior circulation intracranial atherosclerotic disease.

METHODS

Perioperative records of consecutive bypass patients were retrospectively evaluated to determine the clinical course and surgical outcomes.

RESULTS

Arterial bypass was performed in 8 cases with a median age of 62 years. All 8 patients underwent direct bypass with an autologous occipital artery donor vessel. Recipient vessel selection varied on a case-by-case basis, with the superior cerebellar artery used in 4 cases, the posterior inferior cerebellar artery in 3 cases, and the anterior inferior cerebellar artery in 1 case. There were no significant intraoperative or postoperative complications. Postoperatively, all 8 patients displayed clinical improvement of their preoperative symptoms, with a significant decrease of 2.5 points on the modified Rankin Scale (P < .001). Postoperative imaging confirmed full graft patency in 7 patients and partial patency in 1 patient.

CONCLUSION

Excellent postoperative outcomes and no major complications after posterior circulation arterial bypass for intracranial atherosclerotic disease highlight the utility of this intervention for the treatment of medically refractory or symptomatic posterior circulation intracranial atherosclerotic disease. Larger studies may be valuable to validate these findings.

Case report of intracranial large vessel occlusion in glioblastoma multiforme patient after radiation therapy

INTRODUCTION

Vasculopathy of the large arteries is a prominent complication of radiotherapy. Radiation-induced cerebral vasculopathy can cause arterial stenosis/occlusion, cerebral hemorrhage, and aneurysm formation. We report a cases of glioblastoma multiforme (GBM) with occlusive radiation vasculopathy (ORV).

CASE PRESENTATION

This 28-year-old patient who suffered from GBM had surgery for cytoreduction and received postoperative CCRT. We adopted the radiotherapy and oncology group radiation guideline. This patient had cerebrovascular accident episodes without any known risk. Therefore, ORV was highly suspected and vascular stenosis was confirmed using magnetic resonance angiography (MRA) or digital subtraction angiography. Extracranial-intracranial bypass was performed and patency was confirmed. The patient had not suffered from recurrent symptoms of transient ischemic attack or ischemic stroke for 1.5 years.

DISCUSSION

This is the first article to report bypass surgery for GBM patients. Although the median survival rate of GBM is approximately 15 months, the short survival time may be sufficient for occlusive vasculopathy to occur. Regular follow-up magnetic resonance imaging assessments are recommended, as is MRA as a screening tool for the early diagnosis of ORV.The Stenting versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial focused on atherosclerotic intracranial arterial stenosis, revealing that aggressive medical management was superior to stenting for secondary stroke prevention; however, it did not mention radiation-induced vasculopathy. Bypass surgery has yielded some positive outcomes. In the absence of contraindications, antiplatelet or anticoagulation agents could be added, and bypass surgery could be performed because there was no stent in the distal intracranial arteries.

CONCLUSION

MRA is a potential screening tool for ORV in GBM patients and bypass surgery could be performed to improve brain perfusion. Bypass surgery could help patient with occlusive radiation vasculopathy.

Endovascular management of large and giant intracranial aneurysms: Experience from a tertiary care neurosurgery institute in India

Objective

With the development of endovascular technique and devices, large and giant intracranial aneurysms are increasingly being managed by this less invasive method. Here we discuss our experience on managing such aneurysms via endovascular technique.

Methods

Retrospective data on 42 patients with large and giant intracranial aneurysms managed by endovascular techniques between September 2015 to December 2017 at our neurosurgery institute were included in this analysis.

Results

There were a total 42 patients with 9 giant and 33 large aneurysms in this study. Eight aneurysms were treated by parent vessel occlusion, 22 aneurysms with coils and rest 12 aneurysms were treated with stent assisted coiling. Following the procedure, Raymond class I occlusion was accomplished in 31 (73.8%) patients while class Ⅱ in 9 (21.4%) and class Ⅲ in 2 (4.8%) patients. Overall morbidity and mortality were 9.5% and 14.3% respectively and favorable outcome was seen in 80.9% patients. Significant correlation was observed with clinical outcome and initial neurological status.

Conclusions

The study indicates that endovascular intervention is a safe and effective method in managing large and giant intracranial aneurysms with lesser morbidity and mortality.

The evaluation of intracranial bypass patency in neurosurgical practice

BACKGROUND

The patency of cranial bypasses must be carefully evaluated during and after the microsurgical procedure. Although, several imaging techniques are used to evaluate the patency of bypasses, their findings are sometimes difficult to interpret.

PURPOSE

The goal of this study was to assess the consistency of different diagnostic modalities for evaluating intracranial bypass patency.

PATIENTS AND METHOD

This prospective study included 19 consecutive patients treated with EC-IC or IC-IC bypass for MoyaMoya disease (MMD) or complex/giant aneurysms between June 2016 and June 2018. In the early postoperative period (<7 days), all patients had transcranial Doppler (TCD), CT angiography (CTA) and MRA to demonstrate patency of anastomoses and to confirm exclusion of the aneurysm. When findings of anastomosis patency differed between these techniques, conventional angiography was performed.

RESULTS

All anastomoses were patent on indocyanine green videoangiography at the end of microsurgical procedure. The results of noninvasive postoperative exams were consistent to demonstrate the patency of anastomoses in 13 patients. In 4 patients, a discrepancy in patency of anastomoses arose between TCD, CTA and MRI in the early postoperative period. In 2 other patients, the interpretation of bypass patency remained inconclusive before the decision to occlude the aneurysm. In these 6 patients, a significant edema was noted in 2 cases, a postoperative subdural hematoma in 1 case, a low flow in the anastomosis in 1 case and vasospasm in 2 cases. The anastomosis was patent on the conventional angiography in five patients.

CONCLUSION

Noninvasive imaging techniques provide useful data about the patency but their findings should be carefully interpreted due to local anatomical, physiological, and pathological factors. In case of discrepant findings, conventional angiography including supraselective catheterization of the donor vessel is suggested.

Final Results of the Prospective Multicenter Excimer Laser-Assisted High-Flow Bypass Study on the Treatment of Giant Anterior Circulation Aneurysms

BACKGROUND

Both conventional bypass utilizing temporary recipient vessel occlusion and the excimer laser-assisted nonocclusive anastomosis (ELANA) bypass technique are possible strategies in the treatment of giant aneurysms. These treatments have only been studied in single institutional retrospective studies. The potential advantage of the ELANA technique is the absence of temporary occlusion of major arteries, decreasing the risk of intraoperative ischemia.

OBJECTIVE

To investigate the risks and potential benefits of high-flow bypass surgery for giant and complex aneurysms of the anterior cerebral circulation. In addition, the effectiveness of the ELANA bypass procedure in the treatment of these aneurysms is determined.

METHODS

A total of 37 patients were included in 8 vascular neurosurgical centers in the United States, Canada, and Europe. A 30-d postoperative bypass follow-up was studied by using digital subtraction angiography and/or magnetic resonance angiography and computed tomography angiography to assess patency as well as by clinical monitoring in all patients.

RESULTS

In 35 patients, an ELANA high-flow bypass was performed and the aneurysm treated. Four patients had remaining neurological deficits after 30 d caused by stroke (11.4%). These strokes were not related to the ELANA anastomosis device.

CONCLUSION

This study does not prove that the ELANA technique has an advantage over conventional bypass techniques, but it appears to be an acceptable alternative to conventional transplanted high-flow bypass in this very-difficult-to-treat patient group, especially in select patients whom cannot be bypassed using conventional means in which temporary occlusion is considered to be not recommended.

Superficial temporal artery-middle cerebral artery bypass for the treatment of complex middle cerebral artery aneurysms

Objectives:

Direct microsurgical clipping for complex middle cerebral artery (MCA) aneurysms may require a long ischemic time. Sacrifice of the parent artery with trapping or endovascular coiling also may lead to ischemic stroke. We described our institutional experience with the treatment of complex MCA aneurysms using extracranial-intracranial (EC-IC) (superficial temporal artery [STA]-MCA) bypass.

Materials and Methods:

We retrospectively reviewed patients who had treatment of IC aneurysms with the assistance of STA-MCA bypass from July 2002 to December 2016. Six patients with complex MCA aneurysms were identified, and we reviewed their clinical characteristics.

Results:

There were three men and three women with age ranging from 27 to 59 (mean 49) years old. Image studies showed subarachnoid hemorrhage in three cases. All patients underwent STA-MCA anastomosis, and the follow-up period ranged from 2 to 116 months (mean 51.5 months). Two of the six MCA aneurysms were fusiform, two aneurysms had bizarre configurations, one was a dissecting saccular aneurysm, and one had a blister configuration. Three patients received direct vessel trapping, two patients received aneurysm clipping, and one received aneurysm coiling. The postoperative bypass patency rate was 100%. The modified Rankin scale showed good outcomes in the six patients.

Conclusions:

EC-IC bypass plays an important role as a salvage procedure in the treatment of complex MCA aneurysms which have a fusiform, bizarre, or blister configuration.

Falxuplication, a Novel Method for Wrap-Clipping a Fusiform Aneurysm: Technical Note

BACKGROUND

Various techniques have been used for wrap-clipping a ruptured, fusiform intracranial aneurysm; however, there is no available literature on use of the falx cerebri for wrap-clipping. We present a review of the literature, with an illustrative case, of a ruptured fusiform pericallosal artery aneurysm firmly attached to the lower edge of the falx cerebri and not amenable to endovascular intervention.

METHODS

Although the firm attachment between the inferior falx and the fusiform aneurysm was maintained, a section of the lower thinner part of the falx cerebri firmly attached to the aneurysm was dissected and wrapped around the fusiform aneurysm, and then stabilized with a fenestrated clip. We chose a segment slightly longer than the length of the fusiform aneurysm to avoid pre- and post-wrap-clipping stenosis.

RESULTS

Postprocedure, except for a small area of numbness on the left distal anterolateral left leg, the patient was neurologically intact and remained neurologically intact at a 12-month follow-up.

CONCLUSIONS

An inferior thin segment of the falx cerebri can be used for wrap-clipping of ruptured fusiform anterior cerebral artery aneurysms. Furthermore, the inferior falx can be wrapped around the attached fusiform anterior cerebral artery aneurysm without compromising flow, offering a safe solution in these unusually complex cases.

Internal maxillary artery to intracranial artery bypass: a case series of 31 patients with chronic internal carotid/middle cerebral arterial-sclerotic steno-occlusive disease

OBJECTIVE

To evaluate the effectiveness of internal maxillary artery (IMA) - radial artery graft (RAG) - middle cerebral artery (MCA) bypass surgery for chronic arterial-sclerotic severe stenosis or occlusion of the internal carotid artery (ICA) or MCA.

METHODS

A retrospective study was conducted in 31 patients with ischemic cerebrovascular disease who underwent bypass surgery of the IMA with a RAG of the MCA. Twenty-seven patients had complete occlusion of the ICA or MCA, and four patients had severe stenosis of the M1 segment of the MCA.

RESULTS

Patent IMA-RAG-MCA in 30 (96.8%) patients was confirmed by angiography after surgery. One case developed a new motor aphasia due to unsuccessful bypass. Eleven transient ischemic attacks (TIA) and five ischemic strokes resolved following surgery. The other 14 cases showed some improvement without ischemic events at one month following surgery. Prior to surgery, mean ± SD National Institute of Health Stroke Scale (NIHSS) score was 5.4 ± 1.1 in the ischemic stroke group. In the first month post-procedure, the NIHSS score decreased significantly to 3.8 ± 1.2, (p < 0.01). Perfusion weighted imaging (PWI) or computed tomography perfusion (CTP) indicated improved hemodynamics in 30 patients. In addition, seven patients demonstrated improved glucose metabolism on 18-fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography (PET) postoperatively. No new neurological deficit occurred in the 30 patients during a 2.19 ± 1.59 years of follow-up.

CONCLUSIONS

By supplying an adequate flow to a larger flow territory of chronically stenotic/occlusive major cerebral arteries, IMA bypass surgery is efficient for restoring hemodynamics in selected patients and improving their neurological deficits.

Indications and Outcomes of Prophylactic and Therapeutic Extracranial-to-intracranial Arterial Bypass for Cerebral Revascularization

Background:

Extracranial-to-intracranial (EC-IC) arterial bypass is a technically demanding procedure used to treat complex cerebral artery diseases. The indications, proper surgical techniques, and outcomes of this procedure have been under debate over the recent decades.

Methods:

Between January 2004 and December 2012, 28 patients, including patients with cerebral artery occlusion, intracranial aneurysm, cranial base tumor, and Moyamoya disease, underwent EC-IC bypass. Patients’ records were retrospectively reviewed for demography, indications, complications, high-flow versus low-flow bypass, patency rate of bypass, and neurological outcome. The patients were sorted into prophylactic (n = 16) and therapeutic (n = 12) groups based on the preoperative presentation of their neurological symptoms. Follow-up evaluation was performed at a mean of 32.7 ± 24.3 months.

Results:

The overall patency rate of bypass was 100%, the postoperative stroke rate was zero, and the surgical complication rate was 14.3%. There was no significant difference in the bypass patency rate between the 2 groups or between the high-flow and low-flow bypass patients. Patients who underwent prophylactic bypass had minimal surgical and total complications (P = 0.03 and P < 0.01, respectively) and a better neurological outcome. Surgical complications were more common in patients who underwent therapeutic bypass (25%).

Conclusions:

The collaboration of neurosurgeons and plastic surgeons in performing EC-IC bypass can result in excellent outcomes with a high bypass patency rate and few complications, particularly for prophylactic EC-IC bypass.

Endovascular treatment of the distal internal carotid artery large aneurysm

Objective

According to the development of endovascular technique and devices, larger aneurysms on the distal internal carotid artery (ICA) can be treated using a less invasive method. The authors report on clinical and angiographic outcomes of these aneurysms treated using an endovascular technique.

Materials and Methods

Data on 21 patients with large aneurysms at distal ICA treated by endovascular method between January 2005 and December 2012 were included in this retrospective analysis.

Results

Clinical outcome of patients showed strong correlation with the initial neurologic status (p < 0.05). Aneurysm morphology showed saccular, fusiform, and wide-neck in 12, six and three patients. Six patients underwent stent assisted coiling and the other 15 patients underwent simple coiling. Aneurysm occlusion was performed immediately after embolization with near-complete (Raymond class 1-2) in 20 patients (95.2%) and incomplete (Raymond class 3) in one patient (4.8%). Delayed thrombotic occlusion occurred in two patients and their clinical result was fatal. Another five patients died in the hospital, from massive brain edema and/or increased intracranial pressure due to initial subarachnoid hemorrhage. Overall mortality was 30% (seven out of 21). Fatal complication related to the endovascular procedure occurred in two patients with thrombosis at middle cerebral artery (one with stent, the other without it).

Conclusion

Recent developed endovascular device and technique is safe enough and a less invasive method for distal large or giant aneurysms. Based on our analysis of the study, we suspect that coil embolization of large distal ICA aneurysms (with or without stenting) is effective and safe.

Efficacy and outcomes of perioperative anesthetic management of extracranial to intracranial bypass for complex intracranial aneurysm in the absence of advanced neurological monitoring

Background and Aims:

Anesthetic management of extracranial to intracranial (EC-IC) bypass for complex intracranial aneurysms is challenging as the goals involve balancing the cerebral perfusion during parent artery clamping and avoiding factors that predispose to rupture of the unsecured aneurysm. There is very sparse literature available on anesthetic management for this procedure.

Materials and Methods:

A retrospective review of the records of 20 patients undergoing EC-IC bypass was performed with an objective of assessing the efficacy and outcomes of anesthetic management in the absence of advanced neurological monitoring.

Results:

A total of 20 patients underwent EC-IC bypass as an adjunct cerebral revascularization in the management of complex intracranial aneurysms. Intraoperatively normotension and normocarbia were maintained. During the EC-IC bypass, when the temporary clamp was applied, mild hypertension (increase from baseline by 20%) and hypervolemia (central venous pressure increased to 12 mmHg) were maintained. Cerebral protection during temporary clipping of intracranial vessel was provided using moderate hypothermia to 34°C and intravenous thiopentone. Temporary clip time ranged from 15 min to 54 min (mean-25 min). All patients except one were extubated post-operatively (19/20 = 95%). None of the patients had rupture of aneurysm in the peri-operative period. Three patients developed neurologic events (3/20 = 15%). One patient had cerebral vasospasm and two patients developed cerebral infarction. Two patient subsequently improved and one succumbed to the neurological deterioration (mortality 1/20 = 5%).

Conclusion:

Adherence to the principal goals for the procedure, avoidance of hemodynamic fluctuations such as hypotension and hypertension, maintenance of normocarbia, and cerebral protection, result in favorable neurological outcome even in the absence of advanced neuromonitoring.

Perioperative variables contributing to the rupture of intracranial aneurysm: an update

Background. Perioperative aneurysm rupture (PAR) is one of the most dreaded complications of intracranial aneurysms, and approximately 80% of nontraumatic SAHs are related to such PAR aneurysms. The literature is currently scant and even controversial regarding the issues of various contributory factors on different phases of perioperative period. Thus this paper highlights the current understanding of various risk factors, variables, and outcomes in relation to PAR and try to summarize the current knowledge. Method. We have performed a PubMed search (1 January 1991–31 December 2012) using search terms including “cerebral aneurysm,” “intracranial aneurysm,” and “intraoperative/perioperative rupture.” Results. Various risk factors are summarized in relation to different phases of perioperative period and their relationship with outcome is also highlighted. There exist many well-known preoperative variables which are responsible for the highest percentage of PAR. The role of other variables in the intraoperative/postoperative period is not well known; however, these factors may have important contributory roles in aneurysm rupture. Preoperative variables mainly include natural course (age, gender, and familial history) as well as the pathophysiological factors (size, type, location, comorbidities, and procedure). Previously ruptured aneurysm is associated with rupture in all the phases of perioperative period. On the other hand intraoperative/postoperative variables usually depend upon anesthesia and surgery related factors. Intraoperative rupture during predissection phase is associated with poor outcome while intraoperative rupture at any step during embolization procedure imposes poor outcome. Conclusion. We have tried to create such an initial categorization but know that we cannot scale according to its clinical importance. Thorough understanding of various risk factors and other variables associated with PAR will assist in better clinical management as well as patient care in this group and will give insight into the development and prevention of such a catastrophic complication in these patients.

Imaging after direct and indirect extracranial-intracranial bypass surgery

OBJECTIVE

The purpose of this article is to describe the imaging features of different types of surgical cerebral revascularization techniques.

CONCLUSION

Surgical cerebral revascularization involves direct and indirect techniques. Direct revascularization entails anastomosing a branch of the external carotid artery to a cerebral artery. Indirect revascularization involves delivering an extracranial vascular supply in proximity to the surface of the brain. The results of these techniques have distinctive imaging features.

Universal extracranial-intracranial graft bypass for large or giant internal carotid aneurysms: techniques and results in 38 consecutive patients

OBJECTIVE

To present indications, surgical techniques, and outcomes of extracranial-intracranial (EC-IC) graft bypass.

METHODS

Between January 1996 and June 2011, 38 patients with large or giant internal carotid artery (ICA) aneurysms were treated using graft bypass, employing the radial artery (RA) or the saphenous vein (SV) as a graft. Preoperative balloon test occlusions were not performed in any of the cases. In 17 patients, the external carotid artery (ECA)-RA-M2 segment of the middle cerebral artery bypass was used for treatment, and ECA-SV-M2 bypass was used in 21 patients.

RESULTS

All aneurysms were completely trapped, and there were no subarachnoid hemorrhages or recanalizations of aneurysms during the follow-up period (8-170 months). Of the 38 bypasses, 36 (94.7%) remained patent, and there were no permanent neurologic deficits. Hyperperfusion syndrome was not experienced in this series. There were 2 temporary neurologic deficits. In 1 case using the RA, graft vasospasm occurred, and kinking occurred in 1 case using the SV. Another patient with a SV graft had to undergo an emergent revision of the graft 8 hours after the initial operation. One patient with a SV graft underwent a second operation to control an epidural abscess.

CONCLUSIONS

Universal EC-IC graft bypass is a safe and effective method for treating large or giant ICA aneurysms.

Cerebral blood flow after surgery for unruptured cerebral aneurysms: effects of surgical manipulation and irrigation fluid

BACKGROUND

Cerebral blood flow (CBF) is important in the management of cerebrovascular diseases. Surgical manipulation may compromise the appropriate interpretation of postoperative CBF changes, but the effects are not well understood.

OBJECTIVE

To investigate the effect of surgical manipulation on postoperative CBF in a setting of prospective randomized comparison of 2 irrigation fluids during surgery.

METHODS

Twenty patients undergoing the clipping of unruptured cerebral aneurysms through the pterional approach were randomly assigned to use of Artcereb, an artificial cerebrospinal fluid, or physiological saline as irrigation fluid. Postoperative CBF and clinical conditions were evaluated 3 times in the first 7 to 10 postoperative days.

RESULTS

Postoperative CBF decreased by 10 to 15% on the first postoperative day in the ipsilateral inferior frontal gyrus, where surgical manipulation may be greatest. CBF reduction was less in regions remote from the surgical site and later in the follow-up periods. Selection of irrigation fluid did not influence postoperative CBF significantly, although postoperative clinical conditions may be better using Artcereb.

CONCLUSION

Postoperative CBF changes due to surgical manipulation should be considered in patients whose hemodynamic conditions are important for appropriate management.

Endovascular treatment of a ruptured blood blister-like aneurysm with a flow-diverting stent

Treatment of BBAs is currently challenging and remains difficult despite improvement of microsurgical technique and advancement in endovascular technologies. Therapeutic options are reconstructive and deconstructive open surgeries or endovascular procedures. However, there is a lack of consensus about optimal treatment. We report a case of 38-year old woman with subarachnoid hemorrhage due to a ruptured BBA successfully treated with placement of an endovascular flow-diverting stent.