Role of intraoperative angiography in the surgical treatment of cerebral aneurysms

Laser speckle contrast imaging versus microvascular Doppler sonography in aneurysm surgery: A prospective study

Objective

This study aimed to compare microvascular Doppler sonography (MDS) and laser speckle contrast imaging (LSCI) for assessing vessel patency and aneurysm occlusion during microsurgical clipping of intracranial aneurysms.

Methods

MDS and LSCI were used after clip placement during six neurovascular procedures including six patients, and agreement between the two techniques was assessed. LSCI was performed in parallel or right after MDS evaluation. The Doppler response was assessed through listening while flow in the LSCI videos was evaluated by three blinded neurovascular surgeons after the surgery. Statistical analysis determined the agreement between the techniques in assessing flow in 18 regions of interest (ROIs).

Results

Agreement between MDS and LSCI in assessing vessel patency was observed in 87 % of the ROIs. LSCI accurately identified flow in 93.3 % of assessable ROIs, with no false positive or negative measurements. Three ROIs were not assessable with LSCI due to motion artifacts or poor image quality. No complications were observed.

Conclusions

LSCI demonstrated high agreement with MDS in assessing vessel patency during microsurgical clipping of intracranial aneurysms. It provided continuous, real-time, full-field imaging with high spatial resolution and temporal resolution. While MDS allowed evaluation of deep vascular regions, LSCI complemented it by offering unlimited assessment of surrounding vessels.

The Hybrid Operative Suite with Intraoperative Biplane Rotational Angiography in Pediatric Cerebrovascular Neurosurgery: Utility and Lessons Learned

INTRODUCTION

The benefits of performing open and endovascular procedures in a hybrid neuroangiography surgical suite include confirmation of treatment results and reduction in number of procedures, leading to improved efficiency of care. Combined procedural suites are infrequently used in pediatric facilities due to technical and logistical limitations. We report the safety, utility, and lessons learned from a single-institution experience using a hybrid suite equipped with biplane rotational digital subtraction angiography and pan-surgical capabilities.

METHODS

We conducted a retrospective review of consecutive cases performed at our institution that utilized the hybrid neuroangiography surgical suite from February 2020 to August 2021. Demographics, surgical metrics, and imaging results were collected from the electronic medical record. Outcomes, interventions, and nuances for optimizing preoperative/intraoperative setup and postoperative care were presented.

RESULTS

Eighteen procedures were performed in 17 patients (mean age 13.4 years, range 6-19). Cases included 14 arteriovenous malformations (AVM; 85.7% ruptured), one dural arteriovenous fistula, one mycotic aneurysm, and one hemangioblastoma. The average operative time was 416 min (range 321-745). There were no intraoperative or postoperative complications. All patients were alive at follow-up (range 0.1-14.7 months). Five patients had anticipated postoperative deficits arising from their hemorrhage, and 12 returned to baseline neurological status. Four illustrative cases demonstrating specific, unique applications of the hybrid angiography suite are presented.

CONCLUSION

The hybrid neuroangiography surgical suite is a safe option for pediatric cerebrovascular pathologies requiring combined surgical and endovascular intervention. Hybrid cases can be completed within the same anesthesia session and reduce the need for return to the operating room for resection or surveillance angiography. High-quality intraoperative angiography enables diagnostic confirmation under a single procedure, mitigating risk of morbidity and accelerating recovery. Effective multidisciplinary planning enables preoperative angiograms to be completed to inform the operative plan immediately prior to definitive resection.

Comparative Analysis of Feasibility of the Retrograde Suction Decompression Technique for Microsurgical Treatment of Large and Giant Internal Carotid Artery Aneurysms

Objective

Retrograde suction decompression (RSD) is an adjuvant technique used for the microsurgical treatment of large and giant internal carotid artery (ICA) aneurysms. In this study, we analyzed the efficacy and safety of the RSD technique for the treatment of large and giant ICA aneurysms relative to other conventional microsurgical techniques.

Methods

The aneurysms were classified into two groups depending on whether the RSD method was used (21 in the RSD group vs. 43 in the non-RSD group). Baseline characteristics, details of the surgical procedure, angiographic outcomes, clinical outcomes, and procedure-related complications of each group were reviewed retrospectively.

Results

There was no significant difference in the rates of complete neck-clipping between the RSD (57.1%) and non-RSD (67.4%) groups. Similarly, there was no difference in the rates of good clinical outcomes (modified Rankin Scale score, 0–2) between the RSD (85.7%) and non-RSD (81.4%) groups. Considering the initial functional status, 19 of 21 (90.5%) patients in the RSD group and 35 of 43 (81.4%) patients in the non-RSD group showed an improvement or no change in functional status, which did not reach statistical significance.

Conclusion

In this study, the microsurgical treatment of large and giant intracranial ICA aneurysms using the RSD technique obtained competitive angiographic and clinical outcomes without increasing the risk of procedure-related complications. The RSD technique might be a useful technical option for the microsurgical treatment of large and giant intracranial ICA aneurysms.

The role of intraoperative videoangiography in aneurysm surgery—a comparative study from a tertiary care hospital

Background

Indocyanine green (ICG) is a near-infrared (NIR) fluorescent dye. After intravenous injection, it reaches the vessels of the brain within 30 s. A real-time visualization of the cerebral vasculature is possible.

Results

The infarction rate and the postoperative rebleed rate in the pre-ICG era group were higher than in the ICG era.

Conclusion

Intraoperative ICGVA is a safe and effective method to confirm the exclusion of the clipped aneurysm from the circulation. It also helps to assess the patency of the surrounding vessels.

The value of intraoperative angiography in the time of indocyanine green videoangiography in the treatment of cerebrovascular lesions: Efficacy, workflow, risk-benefit and cost analysis A prospective study

INTRODUCTION

Intraoperative digital subtraction angiography (ioDSA) allows early treatment evaluation after neurovascular procedures. However, the value and efficiency of this procedure has been discussed controversially. We have evaluated the additional value of hybrid operating room equipped with an Artis Zeego robotic c-arm regarding cost, efficiency and workflow. Furthermore, we have performed a risk-benefit analysis and compared it with indocyanine green (ICG) angiography.

METHODS

For 3 consecutive years, we examined all neurovascular patients, treated in the hybrid operating theater in a risk-benefit analysis. After using microdoppler and ICG angiography for best operative result, every patient received an additional ioDSA to look for remnants or unfavorable clip placement which might lead to a change of operating strategy or results. Furthermore, a workflow-analysis reviewing operating steps, staff positioning, costs, technical errors or complications were conducted on randomly selected cases.

RESULTS

54 patients were enrolled in the risk-benefit analysis, 22 in the workflow analysis. The average duration of a cerebrovascular operation was 4 h 58 min 2 min 35 s accounted for ICG angiography, 46 min 4 s for ioDSA. Adverse events occurred during one ioDSA. In risk-benefit analysis, ioDSA was able to detect a perfusion rest in 2 out of 43 cases (4,7%) of aneurysm surgery, which could not have been visualized by ICG angiography before. In arterio-venous-malformation (AVM) surgery, one of 11 examined patients (7,7%) showed a remnant in ioDSA and resulted in additional resection. The average cost of an ioDSA in Ulm University can be estimated with 1928,00€.

CONCLUSION

According to our results ioDSA associated complications are low. Relevant findings in ioDSA can potentially avoid additional intervention, however, due to the high costs and lower availability, the main advantage might lie in the treatment of selected patients with complexes neurovascular pathologies since ICG angiography is equally safe but associated with lower costs and better availability.

Hemodynamic changes in superficial arteriovenous malformation surgery measured by intraoperative ICG fluorescence videoangiography with FLOW 800 software

Background

Arteriovenous malformation(AVM) have long-term "blood stealing" characteristics, which result in complicated hemodynamic features. To analyze the application of intraoperative indocyanine green angiography with FLOW 800 software in AVM surgeries.

Methods

Data on 17 patients undergoing surgery with ICG fluorescence were collected in Beijing Tiantan Hospital. To analyze the hemodynamic features of AVM and the influence on the peripheral cortex of AVM resection, we assessed the following hemodynamic parameters: maximum intensity, slope of rise, time to half-maximal fluorescence, and transit time from arteries to veins.

Results

In the 17 superficial AVMs studied, the time-delay color mode of the FLOW 800 software was superior to the traditional playback mode for identifying feeding arteries, draining veins, and their relation to normal cortical vessels. The maximum fluorescence intensity and slope of the ICG fluorescence curve of feeder arteries and draining veins were higher than those of normal peripheral vessels (P < 0.05). The transit times in AVMs were significantly shorter than those in normal peripheral vessels (P < 0.05). After AVM resection, cerebral flow increased in the cortex, and local cycle time becomes longer, although the differences were not significant (P > 0.05).

Conclusions

Hemodynamic parameter analysis provided quality guidance for the resection of AVMs and could also be used in estimating changes in blood flow in the local cortex to identify abnormal hyperperfusion and residual nidus.

Comparison of 3D intraoperative digital subtraction angiography and intraoperative indocyanine green video angiography during intracranial aneurysm surgery

OBJECTIVE

During the last decade, improvements in real-time, high-resolution imaging of surgically exposed cerebral vasculature have been realized with the successful introduction of intraoperative indocyanine green video angiography (ICGVA) and technical advances in intraoperative digital subtraction angiography (DSA). With the availability of 3D intraoperative DSA (3D-iDSA) in hybrid operating rooms, the present study offers a contemporary comparison for rates of accuracy and discordance.

METHODS

In this retrospective study of prospectively collected data, 140 consecutive patients underwent microsurgical treatment of intracranial aneurysms (IAs) in a hybrid operating room. Variables analyzed included patient demographics, aneurysm-specific characteristics, intraoperative ICGVA and 3D-iDSA findings, and the need for intraoperative clip readjustment. The authors defined the discordance rate of the two modalities as a false-negative finding that necessitated clip repositioning after 3D-iDSA.

RESULTS

In 120 patients, ICGVA and 3D-iDSA were used to evaluate 134 IA obliterations. Of 215 clips used, 29 (14%) were repositioned intraoperatively, improving the surgical result in all 29 patients (24%). Repositioning was prompted by visual inspection and microvascular Doppler ultrasonography in 8 (28%), ICGVA in 13 (45%), and 3D-iDSA in 7 (24%) patients. Clip repositioning was needed in 7 patients (6%) based on 3D-iDSA, yielding an ICGVA accuracy rate of 94%. Five (71%) of the ICGVA-3D-iDSA discordances that prompted clip repositioning occurred at the anterior communicating artery complex.

CONCLUSIONS

A combination of vascular monitoring techniques most often achieved correct intraoperative interpretation of complete IA occlusion and parent artery integrity. Compared with 3D-iDSA imaging, ICGVA demonstrated high accuracy. Despite the relatively low discordance rate, iDSA was confirmed to be the gold standard. Improved imaging quality, including 3D-iDSA, supports its routine use in IA surgery, obviating the need for postoperative DSA.

Usefulness of preoperative cone beam computed tomography and intraoperative digital subtraction angiography for dural arteriovenous fistula at craniocervical junction: Technical case report

Background:

Direct surgery is commonly selected for the treatment of cranio-cervical junction dural arteriovenous fistula and its outcome is more satisfactory than that of embolization. Intraoperative treatment evaluation is relatively easy in embolization, whereas in direct surgery it can be difficult.

Case Description:

A 67-year-old male suffered a subarachnoid hemorrhage. On three-dimensional (3D) images of preoperational cone-beam computed tomography (CBCT), the structure of the draining vein was depicted in detail along with the surrounding bone structures. The radial artery penetrated the dura mater, and it was found that there were two veins derived from the radiculospinal vein; one was the anterior radicular vein descending toward the dorsal side (the shallow layer of the surgical field) and the other was the anterior spinal medullary vein ascending toward the ventral side (the deep layer of the surgical field) and flowing out to the anterior spinal vein.

Conclusion:

Without detailed assessments with preoperative CBCT, the surgery might have been done with dissection of only the anterior radicular vein in the shallow layers. For identification of the draining vein located deep in the surgical field, such as the cranio-cervical junction, careful assessments using 3D CBCT images are important.

Early Intracranial Aneurysm Recurrence after Microsurgical Clip Ligation: Case Report and Review of the Literature

Microsurgical clip ligation is considered a definitive treatment for intracranial aneurysms (IAs), resulting in low rates of local recurrence that range from 0.2 to 0.5% and a latency period that averages about a decade. Our case report describes an early asymptomatic recurrence (i.e., without sentinel headache or seizure) less than 1 year after this 20-year-old woman underwent clip ligation of a ruptured anterior communicating artery (AComA) aneurysm. At recurrence, the patient underwent coiling of the regrowth; follow-up imaging at 6 and 18 months demonstrated complete IA occlusion. To review the putative risk factors of this rare phenomenon, the authors searched the PubMed database using the keywords "intracranial aneurysm," "recurrence," and "clipping" in various combinations. In the seven cases identified, all occurred in initially ruptured IA, which was often at the AComA, and six of seven patients were younger than 50 years old. Although most IA remnants grow slowly, early recurrence may represent a more aggressive biological behavior that warrants special attention in younger patients, positive rupture status, and unintended remnant of any size. In such a constellation, early imaging follow-up within the first 6 months may be warranted to rule out early IA recurrence.

The working road map in a neurosurgical Hybrid Angio-Surgical suite------ development and practice of a neurosurgical Hybrid Angio-Surgical suite

Background

The concept of a Hybrid Angio-Surgical Suite (HASS) has emerged as a solution to the complexity of cerebrovascular surgery and the need for immediate intraoperative feedback. When to use it, what cases are suitable for its use, who can use it and how to use it remain debatable.

Objective

Provide the information regarding the application of the HASS for hospital, neurosurgeon and interventionalist.

Methods

We review the literatures of case reports and studies on the use of the hybrid angio-sugical suite along with application of HASS in our own practice.

Results

Indications for using HASS on different types of cerebral vascular disease, including cerebral aneurysm, AVM, DAVF, carotid and vertebral stenosis/occlusion, are addressed. The application of HASS for other non-cerebral vascular diseases, such as trauma, spine and skullbase cases, is reviewed and discussed.

Conclusion

HASS has made many surgical procedures safer and many difficult or previously untreatable conditions much more tractable and cost-effective. Other than used in cerebral vascular disease, HASS has much more applications, such as trauma, spine and other neurosurgical diseases.

Angiographic and epidemiological characteristics associated with aneurysm remnants after microsurgical clipping

BACKGROUND

Despite new techniques for the treatment of cerebral aneurysms, the percentage of aneurysm remnants after surgical intervention seems to be relatively constant. The objective of this study was to assess angiographic and epidemiological features associated with aneurysm remnants after microsurgical clipping.

METHODS

This study was conducted from February 2009 to August 2012 on a series of 90 patients with 105 aneurysms referred to the Santa Casa of Belo Horizonte who were surgically treated and angiographically controlled.

RESULTS

Surgical clipping was considered incomplete in 13.3% of the aneurysms. The mean age of cases with an aneurysm remnant was 57.5 years, whereas the mean age without aneurysm remnant was 49.7 years (P = 0.02). Aneurysm remnants were detected more frequently on the internal carotid artery, nevertheless, no statistically significant differences were verified when comparing the locations. Aneurysm size in the preoperative angiography verified that the mean size of aneurysms operated was 6.56 mm, such that in cases showing a postoperative remnant, the mean size was 9.7 mm and in cases with complete clipping it was 6.08 mm (P = 0.02). Postoperative angiography showed that, in cases with residual aneurysm, the number of clips used was higher - a mean of 1.8 for complete clipping and 3.1 for incomplete clipping (P < 0.001).

CONCLUSIONS

Aneurysm size and patient age showed significant correlations with residual intracranial aneurysm. The mean number of clips used was higher in cases with incomplete occlusion.

Indocyanine Green Videoangiography in Aneurysm Surgery: Systematic Review and Meta-Analysis

BACKGROUND

Although digital subtraction angiography (DSA) may be considered the gold standard for intraoperative vascular imaging, many neurosurgical centers rely only on indocyanine green videoangiography (ICG-VA) for the evaluation of clipping accuracy. Many studies have compared the results of ICG-VA with those of intraoperative DSA; however, a systematic review summarizing these results is still lacking.

OBJECTIVE

To analyze the literature in order to evaluate ICG-VA accuracy in the identification of aneurysm remnants and vessel stenosis after aneurysm clipping.

METHODS

We performed a systematic literature review of ICG-VA accuracy during aneurysm clipping as compared to microscopic visual observation (primary endpoint 1) and DSA (primary endpoint 2). Quality of studies was assessed with the QUADAS-2 tool. Meta-analysis was performed using a random effects model.

RESULTS

The initial PubMed search resulted in 2871 records from January 2003 to April 2016; of these, 20 articles were eligible for primary endpoint 1 and 11 for primary endpoint 2. The rate of mis-clippings that eluded microscopic visual observation and were identified at ICG-VA was 6.1% (95% CI: 4.2-8.2), and the rate of mis-clippings that eluded ICG-VA and were identified at DSA was 4.5% (95% CI: 1.8-8.3).

CONCLUSION

Because a proportion of mis-clippings cannot be identified with ICG-VA, this technique should still be considered complementary rather than a replacement to DSA during aneurysm surgery. Incorporating other intraoperative tools, such as flowmetry or electrophysiological monitoring, can obviate the need for intraoperative DSA for the identification of vessel stenosis. Nevertheless, DSA likely remains the best tool for the detection of aneurysm remnants.

Adenosine-induced transient asystole

Cerebral aneurysms are an important health issue in the United States, and the mortality rate following aneurysm rupture, or SAH, remains high. The treatment of these aneurysms uses endovascular options which include coil placement, stent assistant coiling and, recently, flow diversion. However, microsurgical clipping remains an option in those aneurysms not suited for endovascular therapy. These are often the more complicated aneurysms such as in large, giant aneurysms or deep-seated aneurysms. Circumferential visualization of the aneurysm, parent vessels, branches, perforators, and other neurovascular structures is important to prevent residual aneurysms or strokes from vessel or perforator occlusion. Decompression of the aneurysm sac is often required and we believe that adenosine-induced transient asystole should be an important option for clipping of complex cerebral aneurysms.

Fluorescence in neurosurgery: Its diagnostic and therapeutic use. Review of the literature

Fluorescent agents, e.g. 5-aminolevulinic acid (5-ALA), fluorescein and indocyanine green (ICG) are in common use in neurosurgery for tumor resection and neurovascular surgery. Protoporphyrine IX (PPIX) as major metabolite of 5-ALA is a strong fluorescent substance accumulated within malignant glioma tissue and a very sensitive and specific tool for visualizing high grade glioma tissue during surgery. Furthermore, 5-ALA or rather PPIX also offers an intratumoral therapeutic option stimulated by laser light in specific wavelength. Fluorescein was demonstrated to show similar fluorescent reactions in neurosurgery, but is controversial in its use, especially in high grade tumor surgery. Intraoperative angiography during resection of arterio-venous malformations, extracranial-intracranial-bypass or aneurysm surgery is supported by ICG fluorescence. Generally ICG will provide beneficial information for both, exposure of the pathology and illustration of healthy structures. This manuscript shows an overview of the literature focussing fluorescence in neurosurgery.

Comparing routine versus selective use of intraoperative cerebral angiography in aneurysm surgery: a prospective study

INTRODUCTION

While the use of intraoperative angiography (IA) has been shown to be a useful adjunct in aneurysm surgery, its routine use remains controversial.

OBJECTIVE

We wished to determine if IA is required in all patients undergoing aneurysm surgery (ie, routine IA) or if intraoperative assessment can reliably predict the need for IA (ie, select IA).

METHODS

We prospectively evaluated all patients undergoing craniotomy for aneurysm clipping. In these patients, the treating surgeons were asked to record whether they felt IA was required at two time points: (1) prior to surgery and (2) immediately after clip application but before IA. All patients underwent IA as per the institutional protocol. IA results and the need for post-IA clip adjustments were recorded.

RESULTS

Of the 200 patients enrolled, 197 were included for analysis. IA was deemed necessary on preoperative assessment in 144 cases (73%) and on post-clip assessment in 116 cases (59%). Post-clip IA demonstrated 47 (24%) positive findings and post-IA clip adjustments were made in 19 of 198 cases (10%). On preoperative assessment, there were four cases where IA was deemed unnecessary, yet post-IA clip adjustment was required, resulting in a sensitivity of 79% and false negative rate of 8%. Regarding post-clip assessment, there were five cases where IA was thought to be unnecessary and clip adjustment was required, resulting in a sensitivity of 73% and false negative rate of 6%.

CONCLUSIONS

The accuracy of a strategy of select IA was not improved by assessing the need for IA immediately after aneurysm clipping versus prior to surgery onset. This suggests that intraoperative assessment regarding the adequacy of aneurysm clip application should be viewed with caution.

Intraoperative angiography does not lead to increased rates of surgical site infections

BACKGROUND

Intraoperative angiography (IOA) is essential in evaluating residual aneurysm following clip ligation, but it does lead to an additional procedure which increases the duration of the procedure as well as increasing room traffic. We examined whether IOA during microsurgery is a risk factor for developing cranial surgical site infection.

MATERIALS AND METHODS

A retrospective cohort study was performed of all patients undergoing craniotomy for aneurysm treatment between 2005 and 2012 at the University of Michigan. IOA was used at the surgeons' discretion. The primary outcome of interest was occurrence of a surgical site infection and the secondary outcome of interest was clip repositioning following IOA. Variables including IOA were tested for their independent association with the occurrence of a surgical site infection.

RESULTS

During the study period 676 intracranial aneurysms were treated by craniotomy; IOA was used in 104 of these cases. There were a total of 20 surgical site infections, 2 in the IOA group (1.9%) and 18 in the non-IOA group (3.1%), indicating that IOA was not a statistically significant variable for infection (p=0.50). No additional single variable measured could be shown to have a statistically significant increase in infection, and there were no direct complications related to the use of IOA (stroke, dissection, perforation).

CONCLUSIONS

IOA does not increase the risk of developing a surgical site infection. It can be conducted without exposing patients to an undue risk of infection.

Safety, efficacy, and cost of intraoperative indocyanine green angiography compared to intraoperative catheter angiography in cerebral aneurysm surgery

Intraoperative angiography in cerebrovascular neurosurgery can drive the repositioning or addition of aneurysm clips. Our institution has switched from a strategy of intraoperative digital subtraction angiography (DSA) universally, to a strategy of indocyanine green (ICG) videoangiography with DSA on an as-needed basis. We retrospectively evaluated whether the rates of perioperative stroke, unexpected postoperative aneurysm residual, or parent vessel stenosis differed in 100 patients from each era (2002, "DSA era"; 2007, "ICG era"). The clip repositioning rate for neck residual or parent vessel stenosis did not differ significantly between the two eras. There were no differences in the rate of perioperative stroke or rate of false-negative studies. The per-patient cost of intraoperative imaging within the DSA era was significantly higher than in the ICG era. The replacement of routine intraoperative DSA with ICG videoangiography and selective intraoperative DSA in cerebrovascular aneurysm surgery is safe and effective.

Intraoperative cerebral angiography in arteriovenous malformation resection in children: a single institutional experience

OBJECT

The use of cerebral intraoperative angiography has been described in resection of arteriovenous malformations (AVMs) in adults. More recently, studies have described experiences with intraoperative angiography in a small number of children. However, data on the safety and clinical utility of intraoperative angiography in the pediatric population remains limited in comparison with available data in adults. The aim of the study was to evaluate the use of cerebral intraoperative angiography in children undergoing AVM resection. The clinical utility of intraoperative angiography and procedure-related complications were evaluated.

METHODS

A retrospective review was performed for all patients undergoing cerebral AVM resection with intraoperative angiography at The Children's Hospital of Philadelphia between 2008 and 2012. Patient imaging and operative and medical notes were reviewed to evaluate for end points of the study. A total of 17 patients (8 males, 9 females) were identified, with a median age of 12.1 years (range 1.2-17.9 years) and median weight of 45.5 kg (range 12.1-78.9 kg).

RESULTS

A total of 21 intraoperative angiography procedures were performed for 18 AVM resections in 17 patients. The technical success rate was 94%. In 2 cases (11%), intraoperative angiography demonstrated a residual AVM, and repeat resections were performed. In both cases, no recurrent disease was noted on postoperative follow-up. One procedure-related complication (4.8%) occurred in 1 patient who was positioned prone. Recurrence to date was noted in 2 (14%) of the 14 cases with available postoperative follow-up at 3.5 and 4.7 months following resection with intraoperative angiography. The median follow-up time from intraoperative angiography to the most recent postoperative angiography was 1.1 years (range 4.3 months to 3.8 years).

CONCLUSIONS

Intraoperative angiography is an effective and safe adjunct for surgical management of cerebral AVMs in the pediatric population.

Assessment of the clipping efficacy of intracranial aneurysms: analysis of the employed methodology in relation to case difficulty

OBJECTIVE

To assess intracranial aneurysms clipping efficacy (CE) employing different angiographic techniques in relation to the case difficulty.

METHOD

In the past 6 years, 152 patients harboring 179 aneurysms who underwent surgical clipping in our department were angiographically examined to confirm aneurysm occlusion. Intraoperative angiography (IA), post-operative conventional (PCA) and three-dimensional angiography were single or sequentially performed based on the surgeon's concern about case difficulty. The percentage of visualized angiographic abnormalities (PVAA) assessing CE and their impact on corrective treatment were retrospectively analysed.

RESULTS

The PVAA of IA was 67.8% (19 of 28 aneurysms). Eighteen of them (eight aneurysm remnants, four parent vessel stenosis, two distal branch occlusions and five clip slippage phenomena) underwent immediate corrective treatment (clip reposition in 11 cases, complementary clipping in three cases and combined treatment in four cases). The impact on corrective treatment was 94.7%. The PVAA of PCA was 18.4% (33 of 179 aneurysms). Fifteen patients presented aneurysm remnants, six presented parent vessel stenosis, five presented distal branch occlusions and seven presented clip slippage phenomena. The impact of this technique on corrective treatment was 15.1% (five of 33 angiographic abnormalities). In only one case, PCA demonstrated an aneurysm remnant which was missed on IA. Twenty patients were additionally examined with three-dimensional angiography. The impact on corrective treatment of three-dimensional angiography was 25% (five of 20 examined patients with angiographic abnormalities).

CONCLUSION

In pre-selected difficult cases, IA provides high PVAA and increased impact on corrective treatment. In non-selected patients, PCA shows low PVAA and reduced impact on corrective treatment. The complementary assessment with multiplanar three-dimensional angiography increases the impact on corrective treatment and facilitates decisions about the final case management.

Patterns in neurosurgical adverse events: open cerebrovascular neurosurgery

OBJECT

As part of a project to devise evidence-based safety interventions for specialty surgery, we sought to review current evidence concerning the frequency of adverse events in open cerebrovascular neurosurgery and the state of knowledge regarding methods for their reduction. This review represents part of a series of papers written to consolidate information about these events and preventive measures as part of an ongoing effort to ascertain the utility of devising system-wide policies and safety tools to improve neurosurgical practice.

METHODS

The authors performed a PubMed search using search terms "cerebral aneurysm", "cerebral arteriovenous malformation", "intracerebral hemorrhage", "intracranial hemorrhage", "subarachnoid hemorrhage", and "complications" or "adverse events." Only papers that specifically discussed the relevant complication rates were included. Papers were chosen to be included to maximize the range of rates of occurrence for the reported adverse events.

RESULTS

The review revealed hemorrhage-related hyperglycemia (incidence rates ranging from 27% to 71%) and cerebral salt-wasting syndromes (34%-57%) to be the most common perioperative adverse events related to subarachnoid hemorrhage (SAH). Next in terms of frequency was new cerebral infarction associated with SAH, with a rate estimated at 40%. Many techniques are advocated for use during surgery to minimize risk of this development, including intraoperative neurophysiological monitoring, but are not universally used due to surgeon preference and variable availability of appropriate staffing and equipment. The comparative effectiveness of using or omitting monitoring technologies has not been evaluated. The incidence of perioperative seizure related to vascular neurosurgery is unknown, but reported seizure rates from observational studies range from 4% to 42%. There are no standard guidelines for the use of seizure prophylaxis in these patients, and there remains a need for prospective studies to support such guidelines. Intraoperative rupture occurs at a rate of 7% to 35% and depends on aneurysm location and morphology, history of rupture, surgical technique, and surgeon experience. Preventive strategies include temporary vascular clipping. Technical adverse events directly involving application of the aneurysm clip include incomplete aneurysm obliteration and parent vessel occlusion. The rates of these events range from 5% to 18% for incomplete obliteration and 3% to 12% for major vessel occlusion. Intraoperative angiography is widely used to confirm clip placement; adjuncts include indocyanine green video angiography and microvascular Doppler ultrasonography. Use of these technologies varies by institution.

DISCUSSION

A significant proportion of these complications may be avoidable through development and testing of standardized protocols to incorporate monitoring technologies and specific technical practices, teamwork and communication, and concentrated volume and specialization. Collaborative monitoring and evaluation of such protocols are likely necessary for the advancement of open cerebrovascular neurosurgical quality.

Comparing indocyanine green videoangiography to the gold standard of intraoperative digital subtraction angiography used in aneurysm surgery

Object

The purpose of aneurysm surgery is complete aneurysm obliteration while sparing associated arteries. Indocyanine green (ICG) videoangiography is a new technique that allows for real-time evaluation of blood flow in the aneurysm and vessels. The authors performed a retrospective study to compare the accuracy of ICG videoangiography with intraoperative angiography (IA), and determine if ICG videoangiography can be used without follow-up IA.

Methods

From June 2007 through September 2009, 155 patients underwent craniotomies for clipping of aneurysms. Operative summaries, angiograms, and operative and ICG videoangiography videos were reviewed. The number, size, and location of aneurysms, the ICG videoangiography and IA findings, and the need for clip adjustment after ICG videoangiography and IA were recorded. Discordance between ICG videoangiography and IA was defined as ICG videoangiography demonstrating aneurysm obliteration and normal vessel flow, but post-IA showing either an aneurysmal remnant and/or vessel occlusion requiring clip adjustment.

Results

Thirty-two percent of patients (49 of 155) underwent both ICG videoangiography and IA. The post-ICG videoangiography clip adjustment rate was 4.1% (2 of 49). The overall rate of ICG videoangiography–IA agreement was 75.5% (37 of 49) and the ICG videoangiography–IA discordance rate requiring post-IA clip adjustment was 14.3% (7 of 49). Adjustments were due to 3 aneurysmal remnants and 4 vessel occlusions. These adjustments were attributed to obscuration of the residual aneurysm or the affected vessel from the field of view and the presence of dye in the affected vessel via collateral flow. Although not statistically significant, there was a trend for ICG videoangiography–IA discordance requiring clip adjustment to occur in cases involving the anterior communicating artery complex, with an odds ratio of 3.3 for ICG videoangiography–IA discordance in these cases.

Conclusions

These results suggest that care should be taken when considering ICG videoangiography as the sole means for intraoperative evaluation of aneurysm clip application. The authors further conclude that IA should remain the gold standard for evaluation during aneurysm surgery. However, a combination of ICG videoangiography and IA may ultimately prove to be the most effective strategy for maximizing the safety and efficacy of aneurysm surgery.

Intra operative indocyanine green video-angiography in cerebrovascular surgery: An overview with review of literature

Microscope integrated Near infra red Indocyanine green video angiography (NIR ICG VA) has been frequently used in cerebrovascular surgery. It is believed to be a simple and reliable method with acquisition of real time high spatial resolution images. The aim of this review article was to evaluate the efficacy of intra operative Indocyanine green video angiography (ICG VA) in Aneurysm, brain arteriovenous malformations (AVM) and extracranial-intracranial (EC-IC) bypass surgeries and also to analyze its limitations. Intra operative imaging is a very useful tool in guiding surgery; thus, avoiding surgical morbidity. Now-a-days, many cerebrovascular units are using ICG VA rather than Doppler and intra operative DSA in most of their aneurysm surgeries, and surgeons are incorporating this technique for AVM and in EC-IC bypass surgeries too. This article is an overview of the beneficial effects of ICG VA in cerebrovascular surgery and will also point out its limitations in various circumstances. Intra operative ICG VA gives high resolution, real time images of arterial, capillary, and venous flow of cerebral vasculature. Although it gives adequate information about the clipped neck, parent/branching artery and perforator involvement, it has some limitations like viewing the neck residuals located behind the aneurysm, thick walled atherosclerotic vessels, and thrombosed aneurysms. In AVM surgery, it is useful in detecting the residual nidus in diffuse type AVM, but cannot be relied in deep seated AVMs and it gives exact information about the anastomosis site in EC-IC bypass, thus, avoiding early bypass graft failure. NIR ICG VA is a simple, reliable, and quick method to pick up subtle findings in cerebrovascular procedures. But in selected cases of aneurysms, endoscopy and intra operative Digital substraction angiography (DSA) may be helpful, whereas in deep seated AVMs, navigation may be required as an adjunct to confirm intra operative findings.

Safety and Efficacy of Intraoperative Angiography in Craniotomies for Cerebral Aneurysms and Arteriovenous Malformations

BACKGROUND:

In an era of indocyanine angiography, the routine use of intraoperative angiography (IOA) in the surgical treatment of aneurysms and vascular malformations is controversial.

OBJECTIVE:

To retrospectively assess the safety and efficacy of IOA and to determine predictors of surgical revision.

METHODS:

Between 2003 and 2011, IOA was performed during surgical treatment of 976 aneurysms, 101 arteriovenous malformations (AVMs), and 16 arteriovenous fistulas.

RESULTS:

In 80 of 976 aneurysms (8.2%), IOA prompted clip repositioning. The reason for readjustment was residual aneurysm in 54.7%, parent vessel occlusion in 42.9%, and both in 2.4% of cases. In multivariate analysis, increasing aneurysm size (P &lt; .001), ruptured aneurysm (P &lt; .001), and increasing number of vessels injected (P &lt; .001) were strong predictors of clip readjustment. There was a strong trend for posterior circulation aneurysm location to predict clip repositioning (P = .06). IOA revealed residual nidus/fistula requiring further intervention in 9 of 101 AVMs (8.9%) and 3 of 16 arteriovenous fistulas (18.8%). Of 9 AVMs requiring a surgical revision, 2 (22.2%) were Spetzler-Martin grade II, 5 (55.6%) were grade III, and 2 (22.2%) were grade IV. Mean Spetzler-Martin grade was 3.0 in AVMs requiring surgical revision compared with 2.3 in those not requiring revision (P = .05). IOA-related complications were all transient or minor and occurred in 0.99% of patients; none resulted in permanent morbidity.

CONCLUSION:

IOA remains a valuable tool in the surgical treatment of brain vascular abnormalities, guiding surgical re-exploration in &gt; 8% of cases. Easy access to an angiographer and routine use of IOA are important factors contributing to procedural safety and efficacy.

Prospective Comparison of Intraoperative Vascular Monitoring Technologies During Cerebral Aneurysm Surgery

BACKGROUND:

Microscope integrated intraoperative near-infrared indocyanine green angiography (ICGA) provides assessment of the cerebral vasculature in the operating field.

OBJECTIVE:

To prospectively compare the value of ICGA-derived information during cerebral aneurysm surgery with data simultaneously generated from other intraoperative monitoring and vascular imaging techniques.

METHODS:

Data from 104 patients with 123 cerebral aneurysms who were operated on were prospectively recorded. Results of intraoperative vascular monitoring and descriptions of how this information influenced intraoperative decision making were analyzed.

RESULTS:

Clip repositioning was necessary in 30 of 123 aneurysms (24.4%) treated. Parent artery occlusion was documented by microvascular Doppler ultrasound in 4 aneurysms. ICGA disclosed parent artery stenoses not detected by sonography in 7 cases. Neuroendoscopy was used in 13 cases of midline aneurysms to confirm perforator patency after clipping, and disclosed aneurysm misclipping undetected by ICGA and digital subtraction angiography in 1 aneurysm. The information from DSA and ICGA corresponded in 120 of 123 aneurysms operated on (97.5 %). In 1 patient, ICGA underestimated a relevant parent artery stenosis detected by digital subtraction angiography. In 2 patients with relevant aneurysmal misclipping, digital subtraction angiography and ICGA led to conflicting results that could be clarified only when both methods were used and interpreted together.

CONCLUSION:

The intraoperative monitoring and vascular imaging methods compared were complementary rather than competitive in nature. None of the devices used were absolutely reliable when used as a stand-alone method. Correct intraoperative assessment of aneurysm occlusion, perforating artery patency, and parent artery reconstruction was possible in all patients when these techniques were used in combination.

Microscope integrated indocyanine green video-angiography in cerebrovascular surgery

Microscope integrated indocyanine green video-angiography (ICG-VA) is a new technique for intraoperative assessment of blood flow that has been recently applied to the field of Neurosurgery. ICG-VA is known as a simple and practical method of blood flow assessment with acceptable reliability. Real time information obtained under magnification of operating microscope has many potential applications in the microneurosurgical management of vascular lesions. This review is based on institutional experience with use of ICG-VA during surgery of intracranial aneurysms, AVMs and other vascular lesions at the Department of Neurosurgery at Helsinki University Central Hospital.

Intraoperative Doppler and Duplex sonography in cerebral aneurysm surgery

PURPOSE

The aim of open surgery of cerebral aneurysms is to minimise the risk of infarction due to poor position of a clip while still securing the aneurysm from rebleeding. Whilst digital subtraction angiography (DSA) remains the gold standard for precise evaluation of the result, its invasiveness, risk of thromboembolic infarction, availability and time-consumption pose a significant limitation, and overall it is rarely used. The goal of the present study was to analyse the feasibility of intraoperative B-mode Duplex ultrasound in combination with Doppler sonography (DDS) to evaluate this issue.

METHODS

A total of 44 aneurysms in 40 patients were investigated intraoperatively via B-mode and power Duplex sonography after clip positioning in a prospective setting. Data were then compared to postoperative angiography.

RESULTS

In 38 cases DDS allowed for visualisation of aneurysm localisation, neck and diameter, as well as associated vessels, in accordance to preoperative DSA. This was confirmed by Duplex sonography in 94.7%. Further evaluation of each associated vessel after clip positioning was then enabled by Doppler sonography in 84.8%. Visualisation in terms of B-mode sonography was not successful in six cases due to multiple clips.

CONCLUSION

DDS is an additional tool for immediate evaluation of clipping performance intraoperatively and can be used in simple cases with reliable results. In six cases Doppler-/Duplex-sonography did not illustrate the clipping result sufficiently. It is not yet able to replace DSA in aneurysms with complex configuration.

Peripheral ophthalmic artery aneurysm

Generally speaking, the term "ophthalmic aneurysms" refers to carotid-ophthalmic aneurysms, which arise from the internal carotid artery (ICA) wall at or around the origin of the ophthalmic artery (OA). In contrast, aneurysms arising from the OA stem or its branches, separate from the ICA are called peripheral OA aneurysms (POAAs). POAAs are a rare entity, which clinical features and natural course are not fully understood. A comprehensive literature review of reported aneurysms involving each segment of the OA was undertaken. The demographics, aetiology, clinical manifestations and treatment of reported POAAs are discussed. Of 35 retrieved cases, ten involved the intracranial segment, two were fusiform aneurysms in the optic canal, 17 arose from the intraorbital segment, and 6 involved either the lacrimal or the anterior ethmoidal branches. In 34 cases, clinical details were available; 18 patients experienced moderate to severe visual impairment including blindness, while seven patients had improvement in visual acuity as a result of surgical treatment. The present clinical review reveals that aneurysms of the OA stem and lacrimal branch are potentially threatening to visual acuity, while intracranial segment and anterior ethmoidal aneurysms can rupture and cause subarachnoid or intraparenchymal haemorrhage. Surgical intervention is mandatory in symptomatic cases to prevent visual deterioration or treat aneurismal rupture; alternatively, for small incidental POAAs "watchful waiting" may be indicated.

Intuitiveness, quality and utility of intraoperative fluorescence videoangiography: Australian Neurosurgical Experience

INTRODUCTION

The authors have undertaken a study of their intraoperative experience with indocyanine green fluorescence videoangiography (ICGFV). In particular, the intuitiveness, image quality and clinical utility of this technology have been assessed.

METHODS

The records of forty-six consecutive craniotomies utilising ICGFV have been retrospectively reviewed: There were 27 aneurysms, 2 extracranial-intracranial (EC-IC) bypasses, 5 arteriovenous malformations (AVM), 1 dural arteriovenous fistula (DAVF), 3 cavernomas, 5 meningiomas, and 3 gliomas. ICGFV was used in 5 awake-craniotomy patients. ICGFV was performed using a Leica OH4 surgical microscope with integrated near-infrared camera and ICG-PULSION.

RESULTS

All attempts of intraoperative ICGFV were intuitive. Image quality and resolution were excellent. Arterial and venous phases were comparable to digital subtraction angiography (DSA) but field of view was relatively limited. In 12 operations (26%) the surgeon was substantially benefited from ICGFV findings. In 22 operations (48%), ICGFV was useful but did not influence surgical management. ICGFV was of no benefit in 11 operations (24%) and was misleading in 1 (2%). In this series, ICGFV was of benefit to 1 of 11 (9%) patients with an intracranial neoplasm or cavernoma.

CONCLUSIONS

ICGFV is safe, intuitive and provides neurosurgeons with high quality, valuable, real-time imaging of cerebrovascular anatomy. It can assist in intraoperative surgical management and/or stroke prevention particularly during aneurysm clipping, EC-IC bypass and AVM/DAVF surgery.

Intraoperative Computed Tomographic Angiography in Cerebral Aneurysm Surgery

OBJECTIVE

To assess the feasibility and potential utility of intraoperative computed tomographic angiography (iCTA) in identifying unexpected residual aneurysms and major cerebral artery occlusion after cerebral aneurysm surgery.

METHODS

We prospectively studied 6 consecutive patients with ruptured anterior circulation aneurysms who underwent craniotomy and clipping. iCTA was performed in all cases after the surgeon was satisfied that the aneurysm was completely obliterated and the clip did not occlude a major artery. We analyzed the iCTA images with regard to residual aneurysm and major arterial occlusion and compared them with the postoperatively acquired angiographic images, which served as a control. Patient age and sex, aneurysm location and size, clinical presentation after rupture, and postoperative course, as well as postoperative modified Rankin Scale scores, were also recorded.

RESULTS

One of the 6 patients had a residual aneurysm detected on the iCTA images, and it was confirmed on the immediate postoperative digital subtraction angiography. There were no cases of major arterial occlusion on iCTA imaging or postoperatively acquired angiographic imaging.

CONCLUSION

iCTA is both feasible and potentially useful in identifying unexpected residual aneurysms and major arterial occlusion after surgical clipping of aneurysms.

Application of microscope integrated indocyanine green video-angiography during microneurosurgical treatment of intracranial aneurysms: a review

Indocyanine Green Video Angiography (ICG-VA) is recently introduced to the practice of cerebrovascular neurosurgery. This technique is safe and noninvasive and provides reliable real-time information on the patency of blood vessels of any size, as well as residual filling of aneurysms. In this article, a review of the literature and our experience with ICG-VA during microneurosurgery of intracranial aneurysms is presented.

Intraoperative indocyanine green angiography in intracranial aneurysm surgery: Microsurgical clipping and revascularization

BACKGROUND

The goal of this report is to illustrate the use of intraoperative indocyanine green (ICG) angiography in the surgical management of intracranial aneurysms, including microsurgical clipping and revascularization.

METHODS

This study included a series of 45 patients who were surgically treated between June 2007 and May 2008 for intracranial aneurysms. Fourty-three of the patients had anterior circulation aneurysms, and 2 had posterior circulation aneurysms. Forty-one patients were treated with microsurgical clipping. Four patients underwent revascularization combined with aneurysm dissection or trapping. Intraoperative ICG angiography was used to visualize the aneurysm clipping, patency of parent artery or graft. The ICG angiography technique is described, with particular reference to evaluation of the aneurysm clipping and revascularization.

RESULTS

Eighty-nine ICG angiography procedures were performed in 45 patients with intracranial aneurysms. The aneurysms were completely obliterated for all patients, and the grafts were patented for all except 1 patient. Pre-clipping ICG angiography showed the relationship of aneurysm and its parent artery clearly. After aneurysms being clipped, intraoperative ICG angiography found remnant of aneurysms, stenosis or occlusion of parent arteries and grafts in 8 cases, which were revised in the same surgical procedure. The results of ICG angiography correlated well with postoperative DSA in 97% patients.

CONCLUSION

ICG angiography can provide real-time information and guide revision in the same surgical procedure for the management of intracranial aneurysms.

EVALUATION OF ONYX HD-500 EMBOLIC SYSTEM IN THE TREATMENT OF 84 WIDE-NECK INTRACRANIAL ANEURYSMS

OBJECTIVE

We report our results using Onyx HD-500 (Micro Therapeutics, Inc., Irvine, CA) in the endovascular treatment of wide-neck intracranial aneurysms, which have a high rate of incomplete occlusion and recanalization with platinum coils.

METHODS

Sixty-nine patients with 84 aneurysms were treated. Most of the aneurysms were located in the anterior circulation (80 of 84 aneurysms), were unruptured (74 of 84 aneurysms), and were incidental. Ten presented with subarachnoid hemorrhage, and 15 were symptomatic. All aneurysms had wide necks (neck &gt;4 mm and/or dome-to-neck ratio &lt;1.5). Fifty aneurysms were small (&lt;12 mm), 30 were large (12 to &lt;25 mm) and 4 were giant. Angiographic follow-up was available for 65 of the 84 aneurysms at 6 months, for 31 of the 84 aneurysms at 18 months, and for 5 of the 84 aneurysms at 36 months.

RESULTS

Complete aneurysm occlusion was seen in 65.5% of aneurysms on immediate control, in 84.6% at 6 months, and in 90.3% at 18 months. The rates of complete occlusion were 74%, 95.1%, and 95.2% for small aneurysms and 53.3%, 70%, and 80% for large aneurysms at the same follow-up periods. Progression from incomplete to complete occlusion was seen in 68.2% of all aneurysms, with a higher percentage in small aneurysms (90.9%). Aneurysm recanalization was observed in 3 patients (4.6%), with retreatment in 2 patients (3.3%). Procedural mortality was 2.9%. Overall morbidity was 7.2%.

CONCLUSION

Onyx embolization of intracranial wide-neck aneurysms is safe and effective. Morbidity and mortality rates are similar to those of other current endovascular techniques. Larger samples and longer follow-up periods are necessary.

Microscope-integrated near-infrared indocyanine green videoangiography during surgery of intracranial aneurysms: the Helsinki experience

BACKGROUND

Microscope-integrated near-infrared indocyanine green videoangiography (ICG-VA) is a new method of intraoperative blood flow assessment. The objective of this study was to evaluate the reliability of this technique in the evaluation of neck residuals and patency of branches after microneurosurgical clipping of intracranial aneurysms (IAs).

METHODS

During a period of 14 months, between November 2005 and December 2006, 289 patients with intracranial aneurysms were operated on in our institution. Intraoperative ICG-VA was performed during microneurosurgical clipping of 239 IAs in 190 patients. Postoperative computed tomography and computed tomography angiography (CTA) were performed for all patients. Intraoperative interpretation of ICG-VA in assessing the neck residual or the patency of vessels after clipping of each single aneurysm were recorded and correlated with postoperative CTA and/or digital subtraction angiography.

RESULTS

Postoperative imaging studies revealed no incomplete occlusions of aneurysm domes. Unexpected neck residuals were observed in 14 aneurysms (6%). There were no parent artery occlusions. Unexpected branch occlusions including both major and minor branching arteries were observed in 15 aneurysms (6%).

CONCLUSIONS

Indocyanine green videoangiograph is a simple and fast method of blood flow assessment with acceptable reliability. Indocyanine green videoangiograph can provide real-time information to assess blood flow in vessels of different size as well as the occlusion of the aneurysm. Intraoperative assessment of blood flow in the perforating branches is one of the most important advantages. In selected cases such as giant, complex, and deep-sited aneurysms or when the quality of image in ICG-VA is not adequate, other methods of intraoperative blood flow assessment should be considered.

Role of pre- and intraoperative imaging and neuronavigation in neurosurgery

Advances in neuroimaging acquisition, computing and image processing have enabled neurosurgeons to use radiological imaging to guide both preoperative planning and intraoperative guidance. In preoperative planning, imaging may be used to evaluate surgical risks, choose the best method of intervention and select the safest surgical approach. Neuronavigation may be useful in designing the surgical flap and alerting the surgeon of surrounding anatomy. Finally, intraoperative imaging may be used to define brain shift associated with the resection of intracranial lesions, assist in more complete lesion resection, and monitor for certain intraoperative complications. In the following review, we briefly examine the history of neuroradiology for neurosurgery, neuronavigation and intraoperative imaging and trace their advances to current systems in use. We will also highlight new experimental applications of neuroimaging that are currently being refined.

Computed tomographic angiography in the evaluation of clip placement for intracranial aneurysm

BACKGROUND

Computed tomographic angiography (CTA) has been shown to reliably detect aneurysms pre-operatively. The aim of this study was to compare the ability of post-operative CTA to detect aneurysmal remnants in connection with clip placement compared with digital subtraction angiography (DSA). Furthermore, special attention was paid to identifying factors influencing the image quality of CTA.

METHOD

Between January 2005 and January 2006 a total of 76 patients with intracranial aneurysms were treated in our department. Thirty-two patients with a total of 33 clipped aneurysm were included in this study. All patients underwent CTA and DSA after surgery. Two investigators, each blinded to the classifications of the other, assessed image quality and clip placement.

FINDINGS

In three patients aneurysmal remnants could be detected with CTA and DSA. One 2-mm aneurysmal remnant was not clearly identified on CTA; two small (<2-mm) aneurysmal remnants were definitely not seen on CTA. A single titanium clip was used for aneurysmal clipping in 26 patients, two clips were needed in six patients and one aneurysm required three clips being used. Overall, use of one titanium clip tended to result in better image quality. In addition, clip-gantry angles between 30 degrees and 60 degrees tended to yield better image quality.

CONCLUSION

Post-operatively, CTA can be recommended as a reliable non-invasive diagnostic tool only with optimal image quality and with this criterion up to 66% of the aneurysms can be evaluated. Titanium artefacts, especially in the important zone (<2 mm) around the clip in which small aneurysmal remnants can occur, can render adequate evaluation impossible. CTA image quality depends on the number of titanium clips used, but clip-gantry-angle does not significantly influence the image quality.

Completion angiography for surgically treated cerebral aneurysms: an economic analysis

OBJECTIVE

To compare cost-effectiveness of different strategies for completion angiography after cerebral aneurysm clipping.

METHODS

A literature search was used to determine the outcome probabilities and costs of various strategies. The pooled results were used in a Markov cost-effectiveness model to compare quality-adjusted life-years and costs of each strategy. Sensitivity (threshold) analyses and Monte Carlo simulation were used to test variation in the model.

RESULTS

Routine (for all cases) intraoperative angiography proved to be slightly more cost-effective than selective (only for cases deemed "high risk") intraoperative angiography, being both less costly and more effective. Routine postoperative angiography was the least cost-effective. However, in centers whose rates of clip-induced arterial compromise are much lower than the averages reported in the literature, selective angiography might be warranted.

CONCLUSION

Routine intraoperative angiography remains the most cost-effective form of completion angiography after aneurysm clipping, at least at our present state of technology.

CONTROVERSIES IN THE SURGICAL TREATMENT OF RUPTURED INTRACRANIAL ANEURYSMS

THE MANAGEMENT OF aneurysmal subarachnoid hemorrhage has evolved over time, including the use of the microscope for aneurysm clip application, improved imaging modalities, endovascular methods for aneurysm treatment, dedicated neurointensive care units, and more aggressive therapy for cerebral vasospasm. Although these advancements have reduced the morbidity and mortality associated with aneurysmal subarachnoid hemorrhage, outcomes for this patient population continue to leave much room for improvement. This work highlights controversial adjuvant techniques, maneuvers, and therapies surrounding the surgical treatment of ruptured cerebral aneurysms that currently lack a consensus opinion. These treatments include centralized care in high-volume centers, as well as the use of antifibrinolytic therapy, routine cerebrospinal fluid diversion, intraoperative hypothermia, temporary clip application, neuroprotective drugs, intraoperative angiography, and decompressive hemicraniectomy. Although definitive answers will only be possible through future multicenter collaboration, we review the controversy surrounding these adjuncts and report the consensus opinion from a highly experienced audience.

The validity of intraoperative angiography for the treatment of spinal arteriovenous fistula

STUDY DESIGN

Retrospective study of patients with spinal arteriovenous fistula (AVF) who underwent surgical treatment.

OBJECTIVE

To evaluate the validity of the intraoperative angiography (IA) for the surgical treatment of spinal AVF.

SUMMARY OF BACKGROUND DATA

Owing to the development of interventional techniques, endovascular embolization has become the treatment of choice for AVF, but it is not applicable for every spinal AVF owing to anatomic complexity of the spinal cord vessels. To get effective occlusion of the AVF, IA has been routinely used in the management of cerebral vascular diseases, but report of its use for spinal AVF is rare.

METHODS

Since 2004, 4 consecutive cases of spinal AVF (3 males and 1 female, 3 thoracic, and 1 thoracolumbar) were involved in this study. The mean age at the time of operation was 62.3 years (range from 48 to 76 y). Types of AVFs and surgical techniques were reviewed retrospectively and the outcomes were assessed using the Japanese Orthopedic Association scoring system.

RESULTS

AVFs in 3 patients were diagnosed as the dural type and that in the remaining patient as the perimedullary type; all feeding arteries were derived from the ninth to 10th intercostal arteries. Preoperative angiography demonstrated that the feeding arteries in 2 patients with a dural AVF were the branches of Adamkiewicz artery and in another dural AVF case, the Adamkiewicz artery could not be determined, therefore, endovascular embolization was not feasible. Including a patient with perimedullary AVF, a microsurgical clipping combined with IA was selected as the treatment. Complete occlusion of the fistula was achieved in all cases, the mean preoperative Japanese Orthopedic Association score of 4.5 improved to 6 at the final follow-up, and no perioperative complications were observed during the follow-up period.

CONCLUSIONS

The favorable clinical results in our spinal AVF cases confirmed that IA ensures safe and accurate occlusion of the fistula. This technique provides satisfactory surgical results for spinal AVFs.

Assessment of flow in perforating arteries during intracranial aneurysm surgery using intraoperative near-infrared indocyanine green videoangiography

OBJECTIVE

Perforating arteries are commonly involved during the surgical dissection and clipping of intracranial aneurysms. Occlusion of perforating arteries is responsible for ischemic infarction and poor outcome. The goal of this study is to describe the usefulness of near-infrared indocyanine green videoangiography (ICGA) for the intraoperative assessment of blood flow in perforating arteries that are visible in the surgical field during clipping of intracranial aneurysms. In addition, we analyzed the incidence of perforating vessels involved during the aneurysm surgery and the incidence of ischemic infarct caused by compromised small arteries.

METHODS

Sixty patients with 64 aneurysms were surgically treated and prospectively included in this study. Intraoperative ICGA was performed using a surgical microscope (Carl Zeiss Co., Oberkochen, Germany) with integrated ICGA technology. The presence and involvement of perforating arteries were analyzed in the microsurgical field during surgical dissection and clip application. Assessment of vascular patency after clipping was also investigated. Only those small arteries that were not visible on preoperative digital subtraction angiography were considered for analysis.

RESULTS

The ICGA was able to visualize flow in all patients in whom perforating vessels were found in the microscope field. Among 36 patients whose perforating vessels were visible on ICGA, 11 (30%) presented a close relation between the aneurysm and perforating arteries. In one (9%) of these 11 patients, ICGA showed occlusion of a P1 perforating artery after clip application, which led to immediate correction of the clip confirmed by immediate reestablishment of flow visible with ICGA without clinical consequences. Four patients (6.7%) presented with postoperative perforating artery infarct, three of whom had perforating arteries that were not visible or distant from the aneurysm.

CONCLUSION

The involvement of perforating arteries during clip application for aneurysm occlusion is a usual finding. Intraoperative ICGA may provide visual information with regard to the patency of these small vessels.

Is routine intraoperative angiography in the surgical treatment of cerebral aneurysms justified? A consecutive series of 147 aneurysms

OBJECTIVE

The role of intraoperative angiography (IA) in the surgical treatment of cerebral aneurysms has remained extremely controversial. We determine the frequency and predictors of unanticipated findings necessitating clip adjustment established on postoperative angiography (PA) in a consecutive series of 147 aneurysms. On the basis of published series, we discuss the utility, safety, accuracy, and cost effectiveness of adjunct IA in the surgical treatment of cerebral aneurysms.

METHODS

We retrospectively examined the charts of 124 consecutive patients harboring 147 aneurysms that were surgically clipped between December 2000 and March 2005 and had PA available for review. Patient demographics, aneurysm size, location, Hunt and Hess score, Fisher grade, mode of aneurysm discovery, time between discovery and surgery, and PA results, as determined by a blinded independent neuroradiologist, were recorded.

RESULTS

PA demonstrated two (1.4%) unexpected residuals, four anticipated residuals (2.7%), and four (2.7%) vessel compromises. Of the six unanticipated outcomes, two of two (100%) unexpected residuals and three of four (75%) vessel compromises were from large aneurysms (P = 0.0001 each). Middle cerebral artery aneurysms comprised 5 of 10 (50%) imperfect outcomes (three expected remnants and two vessel occlusions), which trended toward significance (P = 0.06).

CONCLUSION

IA is recommended during the surgical clipping of complex or large aneurysms and some middle cerebral artery aneurysms. High cost-benefit ratio, false-negative rate, and moderate risk, however, preclude routine use. With future technological advances, IA may warrant broader use by replacing postoperative studies in the neurosurgical management of intracranial aneurysms.