Intraoperative angiography in the management of neurovascular disorders

Intraoperative angiography during neurosurgical procedures on patients in prone, three-quarters prone, and park-bench positions: tertiary single-center experience with systematic review and meta-analysis

BACKGROUND

There is limited evidence about the role and effectiveness of intraoperative angiography (IOA) during neurosurgical procedures with patients in prone, three-quarters prone, and park-bench positions.

OBJECTIVE

To carry out a systematic review and meta-analysis of the literature to evaluate the safety and efficacy of IOA during neurosurgical procedures.

METHODS

We reviewed (between January 1960 and July 2022) all studies in which IOAs were performed during neurosurgical procedures with patients in either prone, three-quarters prone, or park-bench positions. Additionally, a cohort of patients from our institutional experience was included. Efficacy outcomes were the rate of successful angiography and the rate of surgical adjustment/revision after IOA. Safety outcomes were the rate of angiography-related complications and mortality. Data were analyzed using a random-effects meta-analysis of proportions, and statistical heterogeneity was assessed.

RESULTS

A total of 26 studies with 142 patients plus 32 subjects from our institution were included in the analysis. The rate of successful intraoperative angiography was 98% (95% CI 94% to 99%; I²=0%). The rate of surgical adjustment/revision was 18% (95% CI 12% to 28%; I²=0%). The rate of complications related to the angiography was 1% (95% CI 0% to 5%; I²=0%). There were no deaths associated with IOA.

CONCLUSION

We found that IOA performed with patients in prone, three-quarters prone, and park-bench positions is feasible and safe with a non-negligible rate of intraoperative post-angiographical surgical adjustment/revision. Our findings suggest that the performance of IOA to complement vascular neurosurgical procedures might have a valuable role in favoring patient outcomes.

Intraoperative angiography via popliteal artery access for spinal neurovascular lesions: an institutional experience and systematic review

BACKGROUND

Intraoperative DSA is used to confirm complete obliteration of neurovascular pathologies. For spinal neurovascular lesions, femoral access can be challenging given the need to flip the patient after sheath placement. Similarly, radial access can be complicated by arch navigation difficulties. Vascular access via the popliteal artery represents an appealing alternative option; however, data regarding its utility and efficacy in these cases are limited.

METHODS

A retrospective series of four consecutive patients between July 2016 and August 2022 who underwent intraoperative spinal DSA via the popliteal artery was analyzed. Additionally, a systematic review was conducted to collect previously reported such cases. Collective patient demographics and operative details are presented to consolidate the available evidence supporting popliteal access.

RESULTS

Four patients met the inclusion criteria from our institution. The systematic review yielded six previously published studies reporting 16 additional transpopliteal access cases. Of the 20 total cases (mean±SD age 60.8±17.2 years), 60% were men. Most treated lesions were dural arteriovenous fistulas (80%) located in the thoracic spine (55%) or cervical spine (25%). The left popliteal artery was most accessed and the highest visualized level was the craniocervical junction. All outcomes were either stable or improving after surgery, and no complications were observed.

CONCLUSIONS

We report the safety and feasibility of transpopliteal access for intraoperative DSA in the prone position in four cases in addition to 16 previously reported cases in the literature. Our case series highlights popliteal artery access as an alternative to transfemoral or transradial access in this setting.

Complementary Tools in Cerebral Bypass Surgery

Cerebral revascularization surgery has been advanced by the refinement of several adjunctive tools. These tools include perioperative blood thinners, intraoperative spasmolytic agents, electrophysiological monitoring, and methods for assessing bypass patency or marking arteriotomies. Despite the array of options, the proper usage and comparative advantages of different complements in cerebral bypass have not been well-cataloged elsewhere. In this literature review, we describe the appropriate usage, benefits, and limitations of various bypass adjuncts. Understanding these adjuncts can help surgeons ensure that they receive reliable intraoperative information about bypass function and minimize the risk of serious complications. Overall, this review provides a succinct reference for neurosurgeons on various cerebrovascular bypass adjuncts.

Intraoperative Angiogram Using C-Arm Fluoroscopy and Direct Common Carotid Artery Puncture During Surgical Treatment of Paraclinoid Aneurysms

BACKGROUND

Intraoperative angiography (IOA) has been shown to be a useful adjunct in surgical treatment of cerebral aneurysms. However, its use can be limited by hybrid operating room availability. On the other hand, the use of C-arm fluoroscopy can add challenges to IOA during navigation of the aortic arch and selection of the great vessels. We aimed to describe a simple method of IOA that can be applied during surgery of paraclinoid aneurysms and can be performed in a normal operating room without the need to navigate the aortic arch.

METHODS

In patients undergoing surgery for paraclinoid aneurysms with need for cervical carotid artery exposure, IOA was performed using a single plane C-arm fluoroscopy unit after direct puncture of the carotid artery.

RESULTS

Five patients were included: 2 with subarachnoid hemorrhage, 2 with unruptured aneurysm and history of subarachnoid hemorrhage, and 1 with unruptured aneurysm. There were 2 internal carotid blister aneurysms, 2 ophthalmic artery aneurysms, and 1 superior hypophyseal artery aneurysm. IOA was performed using direct carotid puncture through the neck incision required for proximal control. In all cases, intraoperative images were of sufficient quality to determine the completeness of aneurysm occlusion as well as parent and branching vessel patency. There were no postoperative infarctions and no complications related to IOA.

CONCLUSIONS

IOA using direct carotid puncture can be performed in a standard operating room with the use of a C-arm, eliminating the need to catheterize the great vessels of the aortic arch.

Role of Indocyanine Green with FLOW 800 in Removal of Hidden Arteriovenous Malformations

OBJECTIVE

Indocyanine green videoangiography (ICG-VA) with FLOW 800 (Carl Zeiss AG) has been used as a visualization tool to guide arteriovenous malformation (AVM) surgery since 2011. We performed a systematic review and evaluated the quality of evidence available on this topic. In addition, we present a series of our own cases demonstrating the unique use of ICG-VA in the localization and removal of deeper seated AVMs.

METHODS

Using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines for systematic reviews, we identified studies related to ICG-VA with FLOW 800 in AVM surgeries using search terms. The studies were screened and reviewed, and the quality of evidence was analyzed using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) criteria. We performed a retrospective review of our own cases of AVM removal with ICG-VA and FLOW 800.

RESULTS

Our search revealed 27 relevant studies, 17 of which met our inclusion criteria. The quality of the body of evidence was determined to be "very low" using the GRADE criteria. We used ICG-VA with FLOW 800 analysis for 14 cases of microsurgical AVM removal. This technique provided unique insights into the localization of deep seated AVMs in 8 cases (57%). No residual AVM was found when assessed by the 6-month follow-up angiogram.

CONCLUSIONS

We present cases highlighting the usefulness of this technique for the localization of certain AVMs. We believe the use of ICG-VA can guide the removal of deeper seated AVMs, because it can reveal surface feeders and draining veins that can be followed to a hidden nidus. Larger, registry-based studies are needed to confirm these findings and improve the overall quality of evidence.

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.

How Reliable Is the Intraoperative Computed Tomography Angiography in Assessing Complete Surgical Resection of Cerebral Arteriovenous Malformations?

BACKGROUND

Digital subtraction angiography (DSA) is still considered the gold standard test to evaluate arteriovenous malformation's (AVM) residual after microsurgical resection.

OBJECTIVE

To evaluate the safety and reliability of intraoperative computed tomography angiography (iCTA) as an immediate method of evaluating the surgical results of AVM resection.

METHODS

We performed a retrospective review for all cases of cerebral AVMs at our institute from January 2015 to April 2020 who underwent surgical resection of cerebral AVM and had iCTA. All included patients underwent a postoperative DSA, and the results were compared with iCTA.

RESULTS

Twenty-eight cases were included. All cases showed complete resection (100%) in the iCTA, and the results were consistent with the postoperative DSA results. The sensitivity of iCTA was 100%. The added operative time ranged from 25 to 30 min. There were no complications related to the use of iCTA.

CONCLUSION

Intraoperative assessment of AVMs surgical results with an iCTA is safe and reliable. The sensitivity of iCTA following AVM resection merits further investigations.

The 100 most cited articles in the endovascular treatment of brain arteriovenous malformations

BACKGROUND:

The literature base for endovascular treatment of brain arteriovenous malformations (BAVMs) has grown exponentially in recent decades. Bibliometric analysis has been used to identify impactful articles in other medical specialties. The aim of this citation analysis was to identify and characterize the top 100 most cited articles in the field of endovascular BAVM treatment.

METHODS:

The top-cited papers were identified by searching selected keywords (“endovascular treatment,” “interventional treatment,” “brain arteriovenous malformation,” “emboliz(s)ation”) on the Web of Science platform. The top 100 articles were ranked according to their number of citations. Each article was further evaluated to obtain predefined characteristics including citation(s) per year, year of publication, authorship, journal-title and impact factor, article topics, article type, and level of evidence.

RESULTS:

The top 100 most cited articles for endovascular BAVM treatment were published between 1960 and 2014. The total number of citations for these articles ranged from 56 to 471 (median 85.5). Most articles (76%) were published between 1990 and 2009 in three journals (56%), originated in the USA (52%) followed by France (16%). The most common topic related to embolization agents and the majority of articles constituted level IV or V evidence.

CONCLUSIONS:

This study provides a comprehensive overview of the most cited articles in the field of endovascular BAVM treatment. Our analysis recognizes key contributions from authors and institutions in the field and leads to a better understanding of the evidentiary framework for BAVM treatment.

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.

Visualization of extracranial-intracranial bypass in moyamoya patients using intraoperative three-dimensional digital subtraction angiography with intravenous contrast injection and robotic C-arm: patient series

BACKGROUND

The authors describe a noninvasive intraoperative imaging strategy of three-dimensional (3D) digital subtraction angiography (DSA) with intravenous (IV) contrast injection, using indocyanine green (ICG) as a test bolus, during extracranial-intracranial (EC-IC) bypass surgery for moyamoya disease.

OBSERVATIONS

Four patients underwent EC-IC bypass surgery in a hybrid operating room. During the surgery, bypass patency was verified using ICG videoangiography and Doppler ultrasonography. After skin closure, the patients under anesthesia underwent IV 3D-DSA with a robotic C-arm in which the scan delay time for the 3D-DSA scan was estimated from the arrival time of ICG during the ICG videoangiography. One day after the surgery, the patients underwent magnetic resonance angiography (MRA). The IV 3D-DSA images were retrospectively compared with those obtained with other modalities. Good bypass patency was confirmed on IV 3D-DSA, ICG videoangiography, Doppler ultrasonography, and postoperative MRA in all cases. The delay time determined using ICG videoangiography as a test bolus resulted in IV 3D-DSA with adequate image quality, allowing assessment of the spatial relationships between the vessels and anastomoses from all directions.

LESSONS

To evaluate bypass patency and anatomical relationships immediately after EC-IC bypass surgery, IV 3D-DSA may be a useful modality. ICG videoangiography can be used to determine the scan delay time.

One-Stage Treatment in a Hybrid Operation Room to Cure Brain Arteriovenous Malformation: A Single-Center Experience

OBJECTIVE

To report the principles and techniques of using a hybrid operation room in the treatment of brain arteriovenous malformation (BAVM).

METHODS

From October 1, 2016 to December 31, 2018, we treated 54 consecutive patients with nonemergent BAVM in a hybrid operation room. The clinical data, radiologic images, and outcomes were collected to establish a prospective database for evaluation.

RESULTS

Thirty-two male and 22 female patients were enrolled with a mean age of 32.6 ± 13.1 years (range, 10-61 years). Bleeding (n = 32, 59.3%) was the main clinical presentation, followed by headache (n = 27, 50.0%), seizures (n = 14, 25.9%), neurofunctional deficits (n = 16, 29.6%), and no symptoms (n = 2, 3.7%). Thirty-one patients (57.4%) accepted resection without intraoperative embolization, 18 (33.3%) were treated with combined embolization and resection, and 5 (9.3%) were cured with intraoperative embolization and resection was cancelled. All patients achieved total BAVM obliteration confirmed with intraoperative angiography. There were no significant differences in outcomes between low-grade (Spetzler-Martin grades I, II, and modified grade III-) and high-grade (Spetzler-Martin grades ≥IV and modified grade III+) groups, except that the high-grade group had more blood loss (667.9 ± 647.5 vs. 284.3 ± 148.6 mL; P = 0.046) and longer postoperative hospitalization (17.1 ± 9.1 vs. 10.8 ± 5.4 days; P = 0.026). At discharge, 52 patients (96.3%) had favorable outcomes (Glasgow Outcome Scale score ≥4). Forty-three patients (79.6%) received 1 year follow-up after treatment; 97.7% (n = 42) of these had ongoing favorable outcomes. However, 4 patients with low-grade BAVM had recurrence.

CONCLUSIONS

The hybrid operation room can ensure safe, comprehensive treatment of BAVM, offering the opportunity for a favorable curative treatment in 1 stage.

Single-Stage Combined Embolization and Resection for Spetzler-Martin Grade III/IV/V Arteriovenous Malformations: A Single-Center Experience and Literature Review

Background and Purpose: This study sought to identify the efficacy and intraoperative operational details of single-stage combined embolization and microsurgery strategy for Spetzler-Martin (SM) grade III/IV/V arteriovenous malformations (AVMs).

Methods: The authors retrospectively reviewed consecutive SM grade III/IV/V AVMs who underwent hybrid procedures and surgical resection alone procedures from January 2016 to February 2018. Outcomes [modified Rankin Scale (mRS)] were compared between hybrid group and surgical resection alone group in ruptured or unruptured subgroup. Factors associated with long-term disability were assessed using multivariable logistic regression analyses.

Results: A total of 100 AVM patients (47 corrected using hybrid procedures whereas 53 by surgical resection alone) were evaluated. After a mean follow-up of 2.3 ± 0.6 years, we found no difference in long-term prognosis and incidences of disability rates between these two strategies. However, the hybrid strategy offers significant advantage in accelerating the resection process [ruptured (P = 0.000); unruptured (P = 0.002)]. In the analysis of risk factors, excessive embolization (Grade C, 60–100%) was significantly associated with long-term disability in the hybrid cohorts (P = 0.041; odds ratio, 24.000; 95% CI, 1.140–505.194), and involvement of deep perforating arteries was the significant predictor of long-term disability in the surgical resection alone cohort (P = 0.025; odds ratio, 15.389; 95% CI, 1.412–167.66). In the subgroup analysis of the hybrid cohort, moderate embolization (Grade B, 30–60%) was recommended because of the low risk ratio of major intraoperative bleeding (P = 0.033).

Conclusions: Single-stage combined embolization and resection is an efficient strategy for the treatment of SM grade III/IV/V AVMs. Although the long-term outcomes were similar to surgical resection alone, the hybrid strategy had obvious advantages of shorter resection. In the hybrid technique, moderate embolization was recommended, and excessive embolization might be detrimental to the subsequent microsurgical resection.

Clinical Trial Registration:http://www.clinicaltrials.gov. Unique identifier: NCT04136860.

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.

Application of hybrid operating rooms for treating spinal dural arteriovenous fistula

BACKGROUND

A hybrid operating room (hybrid-OR) is a surgical space that combines a conventional operating room with advanced medical imaging devices.

AIM

To explore and summarize the technical features and effectiveness of the application of a hybrid-OR in dealing with spinal dural arteriovenous fistulas (SDAVFs).

METHODS

Eleven patients with SDAVFs were treated with the use of a hybrid-OR at the Department of Neurosurgery of our hospital between January 2015 and December 2018. The dual-marker localization technique was used in the hybrid-OR to locate the SDAVFs and skin incision, and the interoperative digital subtraction angiography (DSA) technique was used before and after microsurgical ligation of the fistulae in the hybrid-OR to verify the accuracy of obliteration. The patients were followed for an average of 2 years after the operation, and the preoperative American Spinal Cord Injury Association (ASIA) score and postoperative ASIA score at 6 mo after the operation were compared.

RESULTS

The location and skin incision of the SDAVFs were accurately obtained by using the dual-marker localization technique in the hybrid-OR in all patients, and there were no cases that required expansion of the range of the bone window in order to expose the lesions. Intraoperative error obliteration occurred and was identified in two patients by using the intraoperative DSA technique; therefore, the findings provided by the intraoperative DSA system significantly changed the surgical procedure in these two patients. With the assistance of the hybrid-OR, the feeding artery was correctly ligated in all cases, and the intraoperative error obliteration rate decreased from 18.2% (2/11) to 0%. All 11 patients were followed for an average of 2 years. The ASIA score at 6 mo after the operation was significantly improved compared with the preoperative ASIA score, and there were no patients with late recurrence during the follow-up.

CONCLUSION

Compared with intra-arterial embolization for the treatment of SDAVFs, hybrid-ORs can solve the problem of a higher incidence of initial failure and late recurrence. Compared with direct occlusion of SDAVFs in microsurgery, hybrid-ORs can take advantage of the intraoperative DSA system for locating the shunt and verifying the obliteration of fistulae in order to reduce the error obliteration rate. At this point, our experience suggests that the safety and ease of use make hybrid-ORs combined with microsurgery and intraoperative DSA systems an attractive modality for dealing with SDAVFs.

Radial Arterial Access for Thoracic Intraoperative Spinal Angiography in the Prone Position

BACKGROUND

Verification of complete occlusion or resection of neurovascular lesions is often performed using intraoperative angiography. Surgery for spinal vascular lesions such as arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) is typically performed with the patient in the prone position, making intraoperative angiography difficult. No standardized protocol is available for intraoperative angiography during spinal surgery with the patient in the prone position. We have described our experience using radial artery access for intraoperative angiography in thoracic spinal neurovascular procedures performed with the patient in the prone position.

METHODS

We reviewed the data from all patients who had undergone surgical resection of spinal vascular lesions in the prone position with radial artery vascular access for intraoperative angiography. The patients were treated in a hybrid endovascular operating room.

RESULTS

A total of 4 patients were treated in the prone position using transradial artery access intraoperative angiography for confirmation of complete resection of the vascular lesions. Of the 4 patients, 2 had undergone surgery for a dural AVF, 1 for a pial AVF, and 1 for an AVM of the filum terminale. None of the patients had experienced any procedural complications.

CONCLUSION

Radial artery access for intraoperative angiography during spinal neurovascular procedures in which selective catheterization of a thoracic branch is necessary is feasible, safe, and practical.

Intraoperative Angiography for Arteriovenous Malformation Resection in the Prone and Lateral Positions, Using Upper Extremity Arterial Access

BACKGROUND

Intraoperative angiography is routinely utilized for aneurysms and arteriovenous malformations (AVMs) to verify complete occlusion and resection. Surgery for spinal and posterior fossa neurovascular lesions is usually performed in prone position. Intraoperative angiography in the prone position is challenging and there is no standardized protocol for this procedure.

OBJECTIVE

To describe our experience with intraoperative angiography in the prone and lateral positions, using upper extremity arterial access.

METHODS

We reviewed our experience with intraoperative angiography in the prone position between 2014 and 2015, where vascular access was obtained via the upper extremity arteries. Patients were treated in a hybrid endovascular operating room. High cervical and intracranial lesions were studied via brachial or radial access. All accesses were obtained using ultrasonographic guidance and a small caliber arterial sheath (4F).

RESULTS

Five patients were treated in the prone and lateral positions using brachial/radial artery access. Patients harbored cerebellar AVM, lateral medullary AVM, cervical arteriovenous fistula (AVF), tentorial dural AVF, and tentorial-incisural dural AVF. Patients were positioned prone (n = 2), semiprone (n = 2), and lateral (n = 1) for the surgery. Three patients were treated via right brachial artery access. Two patients were treated via radial arteries access. All patients tolerated the procedures without technical or clinical complications. Intraoperative angiography verified complete occlusion and resection in all cases prior to surgical closure.

CONCLUSIONS

Intraoperative angiography in the prone and lateral positions using upper extremity access is an important adjunct. Brachial or radial access can be obtained safely and provides comfortable and quick approaches.

Safety and Feasibility Assessment of the O-Arm as an Intraoperative Angiography Device in Aneurysm Surgery

OBJECTIVE

To describe the technique and initial experience of using a rotational 3-dimensional (3D) fluoroscopy system (O-arm; Medtronic) as intraoperative angiography (IA) in the surgery of cerebral aneurysms.

METHODS

The 3D IA with O-arm (IAWOA) was performed in a consecutive cohort of patients with unruptured intracranial aneurysms. Conventional microsurgical clipping was performed with the assistance of indocyanine green videoangiography. Then the O-arm chassis was brought in, the ipsilateral internal carotid artery was catheterized, and contrasted images were acquired. Resulting datasets were exported in Digital Imaging and Communications in Medicine and processed using the Osirix software in an accessory computer. The 3D image reconstruction was evaluated intraoperatively to confirm aneurysm occlusion and parent vessel patency. Afterward, agreement among IAWOA, indocyanine green videoangiography, and standard postoperative angiography was analyzed.

RESULTS

The initial pilot study was performed in 6 patients with 7 unruptured aneurysms. The aneurysm occlusion rate was 100%. The concordance of the IAWOA and the standard postoperative angiography was complete, both in terms of occlusion and parent vessel patency. No complications derived from the IAWOA were observed except in 1 patient, who presented a retroperitoneal hematoma without clinical consequences.

CONCLUSIONS

The 3D rotational fluoroscopy (O-arm) device could be safely and effectively used as an IA system in selected patients. To the best of our knowledge, this is the first study reporting its use as an IA device. This technique seems to offer excellent image quality that could be compared with that of the gold standard 3D digital subtraction angiography but with a lower cost and versatility of use for other subspecialties.

Endoscope- versus microscope-integrated near-infrared indocyanine green videoangiography in aneurysm surgery

OBJECTIVE

The quality of surgical treatment of intracranial aneurysms is determined by complete aneurysm occlusion while preserving blood flow in the parent, branching, and perforating arteries. For a few years, there has been a nearly noninvasive and cost-effective technique for intraoperative flow evaluation: microscope-integrated indocyanine green videoangiography (mICG-VA). This method allows for real-time information about blood flow in the aneurysm and the involved vessels, but its limitations are seen in the evaluation of structures located in the depth of the surgical field, especially through small craniotomies. To compensate for these drawbacks, an endoscope-integrated ICG-VA (eICG-VA) was developed. The objective of the present study was to assess the use of eICG-VA in comparison with mICG-VA for intraoperative blood flow evaluation.

METHODS

In the period between January 2011 and January 2015, 216 patients with a total of 248 intracranial saccular aneurysms were surgically treated in the Department of Neurosurgery of Saarland University Medical Center in Homburg/Saar, Germany. During 95 surgeries in 88 patients with a total of 108 aneurysms, intraoperative evaluation was performed with both eICG-VA and mICG-VA. After clipping, evaluation of complete aneurysm occlusion and flow in the parent, branching, and perforating arteries was performed using both methods. Intraoperative applicability of each technique was compared with the other and with postoperative digital subtraction angiography as a standard evaluation technique.

RESULTS

Evaluation of completeness of aneurysm occlusion and of flow in the parent, branching, and perforating arteries was more successful with eICG-VA than with mICG-VA, especially for aneurysm neck assessment (88.9% vs 69.4%). For 63.9% of the aneurysms (n = 69), both methods were equivalent, but in 30.6% of the cases (n = 33), the eICG-VA provided better results for evaluating the post-clipping situation. In 4.6% of these aneurysms (n = 5), the information given by the additional endoscope considerably changed the surgical procedure. Thus, one residual aneurysm (0.9%), two neck remnants (1.9%), and two branch occlusions (1.9%) could be prevented. Nevertheless, two incomplete aneurysm occlusions (1.9%) and six neck remnants (5.6%) were revealed by postoperative digital subtraction angiography.

CONCLUSIONS

Endoscope-integrated ICG-VA seems to be an improvement that might increase the quality of aneurysm surgery by providing additional information. It offers higher illumination, magnification, and an extended viewing angle. Its main advantage is its ability to assess deep-seated aneurysms, especially through small craniotomies, but further studies are required.

Intraoperative angiography via the popliteal artery: a useful technique for patients in the prone position

OBJECTIVE Intraoperative angiography can be a valuable tool in the surgical management of vascular disorders in the CNS. This is typically accomplished via femoral artery puncture; however, this can be technically difficult in patients in the prone position. The authors describe the feasibility of intraoperative angiography via the popliteal artery in the prone patient. METHODS Three patients underwent intraoperative spinal angiography in the prone position via vascular access through the popliteal artery. Standard angiography techniques were used, along with ultrasound and a micropuncture needle for initial vascular access. Two patients underwent intraoperative angiography to confirm the obliteration of dural arteriovenous fistulas. The third patient required unexpected intraoperative angiography when a tumor was concerning for a vascular malformation in the cervical spine. RESULTS All 3 patients tolerated the procedure without complication. The popliteal artery was easily accessed without any adaptation to typical patient positioning for these prone-position cases. This proved particularly beneficial when angiography was not part of the preoperative plan. CONCLUSIONS Intraoperative angiography via the popliteal artery is feasible and well tolerated. It presents significant benefit when obtaining imaging studies in patients in a prone position, with the added benefit of easy access, familiar anatomy, and low concern for catheter thrombosis or kinking.

Combined Surgical and Endovascular Treatment of a Complex Posterior Communicating Artery Aneurysm at One-Stage in a Hybrid Operating Room

BACKGROUND

Although clipping and coiling of intracranial aneurysms are effective treatment options, they each have limitations. With the advent of the hybrid operating room, combined clipping and coiling for complex aneurysms in one stage becomes feasible. We report a successful case of a left posterior communicating artery aneurysm where combined clipping and endovascular treatment were applied.

CASE DESCRIPTION

A 57-year-old man had been complaining of severe headache for 10 days. The computed tomography scan from a previous hospital revealed a parasellar lesion, and the computed tomography angiography in our hospital showed a 16-mm posterior communicating artery aneurysm. Clipping of the aneurysm was scheduled in our hybrid operating room, which enabled intervention of intraoperative digital subtraction angiography (DSA). However, once the aneurysm was clipped, intraoperative DSA revealed that the aneurysm was remnant. We readjusted the clip and reran DSA, but the residual neck was still present. In an effort to preserve the parent artery and perforators, we decided to perform endovascular treatment. Coiling was achieved, followed by angiography, indicating that the aneurysm was almost eliminated. Overall, the patient underwent 4 angiographic explorations during surgery.

CONCLUSIONS

Combined open surgical and endovascular approaches to treat complex cerebral aneurysms in an hybrid operating room could offer an alternative when the aneurysms appear unclipped or remnant intraoperatively. In our experience, simultaneous clipping and coiling is a safe and effective procedure for efficient treatment of aneurysms.

A Critical Analysis of the Utility of Intraoperative Angiography

OBJECTIVE

Intraoperative digital subtraction angiography (ioDSA) is touted as the gold standard imaging evaluation for aneurysm clip constructs. Candid evaluations of its limitations are sparse.

METHODS

A prospectively collected hospital billing database was queried to identify craniotomies for aneurysm clipping from January 2010 to December 2013. We evaluated the rate of occult residual and parent vessel stenosis determined on follow-up angiography for patients undergoing ioDSA and those not undergoing ioDSA. Comparisons were performed via Fisher exact test, with P < 0.05 considered statistically significant.

RESULTS

From our database search, we found 187 patients who underwent ioDSA after aneurysm clipping and an additional 91 patients who did not. Results from ioDSA influenced operative management in 17% of cases. Sixty-four patients with 70 treated aneurysms undergoing ioDSA had postoperative angiography; 7 occult residuals were discovered, yielding a 10% false-negative rate, with 10% of aneurysms showing residual. Occult residuals at the middle cerebral artery bifurcation represented most discovered residuals (6/7). Thirty-two patients with 37 treated aneurysms did not undergo ioDSA and had angiographic follow-up; 24% of patients were found to have residual aneurysms (P = 0.08 compared with patients undergoing ioDSA). Residuals at the anterior communicating artery (ACoA) represented 56% of all residuals, whereas the ACoA represented only 18% of aneurysms clipped. The rate of residuals was significantly higher than that for patients with clipped ACoA aneurysms undergoing ioDSA (P = 0.008).

CONCLUSIONS

ioDSA influenced management in nearly one fifth of cases. It can be particularly beneficial in detecting residuals for ACoA aneurysms; its benefit was less apparent for middle cerebral artery aneurysms.

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.

Clipping of ruptured intracranial aneurysms in a hybrid room environment-a case-control study

BACKGROUND

Hybrid room treatment (HRT) provides the surgeon immediate intraoperative angiography control of aneurysm occlusion and vessel patency. Since it is relatively resource demanding, in clinical routine HRT is reserved for elective cases. However, since its introduction in our department in 2008, several random cases of ruptured intracranial aneurysms (IAs) have been treated in the HR. This study aims to compare the clinical and radiological outcomes of these cases with cases treated conventionally using a matched pair analysis.

METHODS

Twenty (20%) consecutive patients with ruptured IA treated by microsurgical clipping in the HR between 2009 and 2015 were retrospectively matched with "conventionally" (C) treated patients (overall n = 101). Clinical and radiological outcome variables were assessed and compared.

RESULTS

Despite a trend in favor of the HR group, no significant difference between both matched groups (HR vs. C) could be demonstrated regarding the functional outcome (upper/lower good recovery 16/20 vs. 17/20, p > 0.05), frequency of clipping-related vascular insults on CT scans (0/20 vs. 3/20, p > 0.05), aneurysm remnant rate on postoperative angiography (1/20 vs. 4/20, p > 0.05) and retreatment rate (0/20 vs. 1/20, p > 0.05). When cumulating all outcome events by a scoring system, however, the HR cohort showed a significantly lower occurrence of events (p < 0.05). In three cases co-treatment by an endovascular approach was performed in the HR cohort.

CONCLUSION

In this relatively small cohort, a matched pair analysis revealed a discrete but not significant tendency toward a lower frequency of aneurysm remnants and clipping-related vascular insults in the HR cohort. However, HR cohort patients benefited from direct endovascular co-treatment in selected cases.

The Clinical Importance of Perforator Preservation in Intracranial Aneurysm Surgery: An Overview with a Review of the Literature

Clipping for intracranial aneurysms is done to achieve complete occlusion of the aneurysm without a remnant sac. Despite modern advancements of neurosurgical techniques, morbidity related to the clipping of intracranial aneurysms still exists. Clip occlusion of a parent artery or small hidden perforators commonly leads to permanent neurological deficits, and is a serious and unwanted complication. Thus, preserving blood flow in the branches and perforators of a parent artery is very important for successful surgery without postoperative morbidity and mortality. The aim of this review article is to discuss the consequences of perforator injury and how to avoid this phenomenon in aneurysm surgeries using intraoperative monitoring devices.

Application of fluorescein sodium videoangiography in surgery for spinal arteriovenous malformation

We present our recent experience with fluorescein sodium videoangiography (FLVA) in the intra-operative evaluation of a patient with conus medullaris arteriovenous malformation (AVM). To our knowledge this is the first report in the literature of use of FLVA in the surgery of spinal AVM. Intra-operative FLVA was done to identify an early filling vessel and to obliterate the site of fistulous connection. This was correlated and confirmed with simultaneous indocyanine green videoangiography (ICGVA). The conus and cauda equina roots could be appreciated and manipulated in relation to this fluorescence. Obliteration was confirmed with FLVA and correlated with ICGVA. There was no untoward reaction to the dye injection. We conclude that FLVA is a useful adjunct in the surgical treatment of conus medullaris AVMs since it is a real time, noninvasive, radiation-free, easily reproducible technique allowing surgical manipulation through the operating oculars with simultaneous visualization of surrounding critical structures.

Intraoperative spinal digital subtraction angiography: indications, technique, safety, and clinical impact

Background

Cerebral intraoperative DSA (IODSA) is a well-described, routinely performed procedure that allows the effectiveness of cerebrovascular interventions to be evaluated in the operating room. Spinal IODSA, on the other hand, is infrequently obtained and has received less attention.

Objective

To discuss the indications, technique, safety, and clinical impact of spinal IODSA.

Materials and methods

Twenty-three patients underwent 45 thoracic and/or lumbar spinal IODSA between 2005 and 2016, either immediately before surgery for lesion localization or after the intervention to evaluate its effectiveness. Indications included 21 vascular malformations and 2 diaphragmatic crus compression syndromes. A long femoral arterial sheath with its hub positioned on the lateral surface of the thigh was used to allow catheter manipulations in the prone position.

Results

All targeted intersegmental arteries (ISAs) were successfully catheterized. The course of surgery was changed in 6 instances (26.1%). In 4 cases of epidural or perimedullary arteriovenous fistulae (AVFs), a residual lesion required additional intervention. In one case of epidural AVF, initial IODSA revealed spontaneous resolution of the lesion, preventing unnecessary surgery. Finally, angiography performed in a case of diaphragmatic crus syndrome showed thrombosis of the ISA and non-visualization of the artery of Adamkiewicz. Recanalization was obtained by IA thrombolysis, with excellent clinical outcome. No intraprocedural or postprocedural complication was noted.

Conclusions

Spinal IODSA is a safe technique that offers an immediate assessment of the effectiveness of a spinovascular surgical procedure, notably epidural and perimedullary AVFs. Spinal IODSA was technically successful in all cases, influencing the surgical strategy in 6 of 23 patients, including one patient who benefited from intraoperative endovascular therapy.

Avoidance of ischemic complications after resection of a brain lesion based on intraoperative real-time recognition of the vasculature using laser speckle flow imaging

OBJECTIVE To avoid ischemic complications, it is important to consider the arteries in resection planning for lesions such as a vascular intraparenchymal tumor and arteriovenous malformation. Here, the clinical application of laser speckle flow imaging (LSFI) as a complementary method for the management of mass lesion-related arteries during surgery was evaluated. METHODS LSFI was performed in 12 patients with mass lesion-related arteries and brain tumor or arteriovenous malformation. The portable LSFI device was centered over the surgical field, and the relative cerebral blood flow (CBF) before and after the temporary interruption of the arteries was measured through continuous recording. CBF fluctuations permitted the classification of 3 kinds of artery-a feeding artery (FA), a "passing through" artery (PA), and a combined FA and PA (FA+PA)-based on decreased relative CBF in the inner resection area and unchanged CBF in the surrounding area (FA), unchanged CBF in the inner area and decreased CBF in the surrounding area (PA), or decreased CBF in both areas (FA+PA). This information allowed the appropriate management of these arteries and avoidance of postoperative ischemic complications. RESULTS Good visualization of CBF in the surgical field and relative CBF measurements in the regions of interest were achieved in real time with excellent spatiotemporal resolution. In 11 patients (92%) and 20 regions of interest, a decline in CBF was observed after temporary interruption of the FA (n = 8), PA (n = 2), and FA+PA (n = 2) types. There was a significant average reduction in CBF of 15.3% ± 29.0%. There were no ischemic complications, and only 1 patient had a postoperative ischemic lesion caused by resection through an artery that could not be viewed by LSFI due to a positional problem. CONCLUSIONS LSFI permits noninvasive and rapid intraoperative real-time recognition of mass lesion-related vasculature. This information can be used to avoid ischemic complications as a procedure complementary to neurophysiological monitoring.

Usefulness of repetitive intraoperative indocyanine green-based videoangiography to confirm complete obliteration of micro-arteriovenous malformations

Background:

It is difficult to intraoperatively confirm the total disappearance of arteriovenous (AV) shunts during surgery for microarteriovenous malformations (micro-AVMs), especially when the nidus is extremely small or diffuse on preoperative angiography. Although intraoperative angiography is effective for evaluating residual shunts, procedure-related risks raise important concerns. The purpose of this study was to assess the usefulness of intraoperative indocyanine green-based videoangiography (ICG–VA) to determine complete disappearance of micro-AVMs during surgery.

Methods:

We retrospectively analyzed eight patients with ruptured micro-AVMs who were treated using craniotomy with ICG–VA at our institution.

Results:

Two patients underwent emergency partial evacuation of hematoma and external decompression before the diagnostic angiography. While three patients had a nidus smaller than 1 cm, five patients had only early draining veins without an appreciable nidus. The draining veins were superficial in six cases and deep in two cases. The average interval from onset to surgery was 33 days (range, 2–57). ICG–VA was repetitively conducted until disappearance of the AV shunt was confirmed. No residual AV shunt was observed on postoperative radiological examinations. In all cases, the diagnosis of AVM was confirmed from the results of postoperative pathological examination.

Conclusions:

ICG–VA could detect early draining veins more clearly in situ than diagnostic angiography. Although it is not as effective for visualizing lesions with deep draining veins, repetitive ICG–VA was safe and effective for confirming the disappearance of AV shunts with superficial drainage.

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.

Comparison of indocyanine green fluorescent angiography to digital subtraction angiography in brain arteriovenous malformation surgery

BACKGROUND

The potential utility of intraoperative microscope-integrated indocyanine green (ICG) fluorescence angiography in the surgery of brain arteriovenous malformations (AVMs) and evaluation of the completeness of resection is debatable. Postoperative catheter angiography is considered the gold standard. We evaluated the value of ICG and intraoperative catheter angiography in this setting.

METHODS

Between January 2009 and July 2013, 37 patients with brain AVMs underwent surgical resection of their vascular lesions. ICG videoangiography and an intraoperative catheter angiography were performed in 32 cases, and a routine postoperative angiogram was performed within 48 h to 2 weeks after surgery. The usefulness of ICG findings and the ability to confirm total resection and to identify residual nidus or persistent shunt were assessed and compared to intraoperative and postoperative digital subtraction angiography, respectively.

RESULTS

There were 7 grade 1, 11 grade 2, 11 grade 3 and 3 grade 4 Spetzler-Martin classification AVMs. ICG angiography helped to distinguish AVM vessels in 26 patients. In 31 patients, it demonstrated that there was no residual shunting. In one patient, a residual AVM was identified and further resected. Intraoperative catheter angiography detected two additional small residuals that were missed by ICG angiography, both deep in the surgical cavity. Further resection of the AVM was performed, and total resection was confirmed by a repeat intraoperative angiogram. Postoperative angiography in a patient with a grade 4 lesion revealed one additional small deep residual AVM nidus with persistent late shunting missed on both ICG and intraoperative angiography. Overall ICG angiography missed three out of four residual AVMs after initial resection, while the intraoperative angiogram missed one.

CONCLUSION

Although ICG angiography is a helpful adjunct in the surgery of some brain AVMs, it's yield in detecting residual AVM nidus or shunt is low, especially for deep-seated lesions and higher grade AVMs. ICG angiography should not be used as a sole and/or reliable technique. High-resolution postoperative angiography must be performed in brain AVM surgery and remains the best test to confidently confirm complete AVM resection.

Usefulness of the indocyanine green fluorescence endoscope in endonasal transsphenoidal surgery

OBJECT

To avoid disorientation during endoscopic endonasal transsphenoidal surgery (ETSS), the confirmation of anatomical landmarks is essential. Neuronavigation systems can be pointed at exact sites, but their spatial resolution power is too low for the detection of vessels that cannot be seen on MR images. On Doppler ultrasonography the shape of concealed arteries and veins cannot be visualized. To address these problems, the authors evaluated the clinical usefulness of the indocyanine green (ICG) endoscope.

METHODS

The authors included 38 patients with pituitary adenomas (n = 26), tuberculum sellae meningiomas (n = 4), craniopharyngiomas (n = 3), chordomas (n = 2), Rathke's cleft cyst (n = 1), dermoid cyst (n = 1), or fibrous dysplasia (n = 1). After opening the sphenoid sinus and placing the ICG endoscope, the authors injected 12.5 mg of ICG into a peripheral vein as a bolus and observed the internal carotid arteries (ICAs), cavernous sinus, intercavernous sinus, and pituitary.

RESULTS

The ICA was clearly identified by a strong fluorescence signal through the dura mater and the covering thin bone. The intercavernous and cavernous sinuses were visualized a few seconds later. In patients with tuberculum sellae meningiomas, the abnormal tumor arteries in the dura were seen and the vague outline of the attachment was identified. At the final inspection after tumor removal, perforators to the brain, optic nerves, chiasm, and pituitary stalk were visualized. ICG fluorescence signals from the hypophyseal arteries were strong enough to see and spread to the area of perfusion with the passage of time.

CONCLUSIONS

The ICA and the patent cavernous sinus were detected with the ICG endoscope in real time and at high resolution. The ICG endoscope is very useful during ETSS. The authors suggest that the real-time observation of the blood supply to the optic nerves and pituitary helps to predict the preservation of their function.

Contrast-enhanced angiographic computed tomography for detection of aneurysm remnants after clipping: a comparison with digital subtraction angiography in 112 clipped aneurysms

BACKGROUND

For preclusion of remnants after aneurysm clipping, a reliable, noninvasive imaging technique is desirable.

OBJECTIVE

To evaluate the reliability of optimized angiographic computed tomography with intravenous contrast agent injection (ivACT) in detecting remnants after aneurysmal clipping compared with digital subtraction angiography (DSA), the gold standard.

METHODS

We included 84 patients with 112 clipped cerebral aneurysms of the anterior circulation. For treatment, 116 clips of cobalt and 57 clips of titanium alloy were used. In each patient, we performed an ivACT with dual rotational acquisition and a DSA. Data from ivACT were postprocessed with a dual-volume technique with newly implemented reconstructions modes. Aneurysm remnants were measured, classified, and correlated with DSA by 2 raters.

RESULTS

In total, 12 remnants were revealed by DSA, meaning a prevalence of 11%. IvACT demonstrated a sensitivity of 75% to 92% and a specificity of 99% in detecting remnants up to a minimal size of 0.7 × 0.3 mm. Classification of remnants by ivACT was identical to that by DSA, and assessment of size showed a significant correlation with DSA (P < .001). No significant differences between cobalt and titanium alloy were revealed concerning artifacts.

CONCLUSION

Optimized ivACT with enhanced postprocessing demonstrated high sensitivity and specificity in detecting remnants after aneurysm clipping in the anterior circulation. Classification and assessment of remnant size and detection of relevant parent artery stenosis showed high accuracy of ivACT compared with DSA. Our results indicate that ivACT might become a noninvasive alternative to DSA for postsurgical control.

Indocyanine green angiography in the surgical management of cerebral arteriovenous malformations: lessons learned in 130 consecutive cases

BACKGROUND

Indocyanine green (ICG) angiography is commonly used to map the vascular configuration of cerebral arteriovenous malformations (AVMs) during resection.

OBJECTIVE

To determine whether ICG improves rates of resection and clinical outcomes.

METHODS

A retrospective chart review was done for all patients undergoing resection of an AVM by the senior author (R.F.S.) between 2007 and 2011. Operative reports, hospital records, and radiographic imaging were used to determine the use of ICG, the incidence of residual disease, and clinical outcomes.

RESULTS

A total of 130 cases (56 ICG, 74 non-ICG) were identified. Average AVM grade (2.2 vs 2.4) and size (2.7 vs 2.7 cm) were similar between the ICG and non-ICG groups, respectively. ICG was more often used when the AVM nidus was close to the cortical surface (71.4% vs 17.6%; P = .001) or lobar (82.1% vs 54.1%; P = .008). Eighteen patients (13.8%) were noted to have residual disease. Reoperation rates and change in modified Rankin Scale score were not different between the 2 groups (12.5% vs 14.9%, P = .8; 0.6 vs 0.4, P = .17). There were no ICG-attributable complications.

CONCLUSION

ICG videoangiography is a quick and safe method of intraoperatively mapping the angioarchitecture of superficial AVMs, but it is less helpful for deep-seated lesions. This modality alone does not improve the identification of residual disease or clinical outcomes. Surgeon experience with extensive study of preoperative vascular imaging is paramount to achieving acceptable clinical outcomes. Formal angiography remains the gold standard for the evaluation of AVM obliteration.

Indocyanine green fluorescence endoscopy at endonasal transsphenoidal surgery for an intracavernous sinus dermoid cyst: case report

The complete resection of intracavernous sinus dermoid cysts is very difficult due to tumor tissue adherence to important anatomical structures such as the internal carotid artery (ICA), cavernous sinus, and cranial nerves. As residual dermoid cyst tissue sometimes induces symptoms and repeat surgery may be required after cyst recurrence, minimal invasiveness is an important consideration when selecting the surgical approach to the lesion. We addressed a recurrent intracavernous sinus dermoid cyst by the endoscopic endonasal transsphenoidal approach assisted by neuronavigation and indocyanine green (ICG) endoscopy to confirm the ICA and patency of the cavernous sinus. The ICG endoscope detected the fluorescence signal from the ICA and cavernous sinus; its intensity changed with the passage of time. The ICG endoscope was very useful for real-time imaging, and its high spatial resolution facilitated the detection of the ICA and the patent cavernous sinus. We found it to be of great value for successful endonasal transsphenoidal surgery.

Comparison of Intraoperative Microscopic and Endoscopic ICG Angiography in Aneurysm Surgery

BACKGROUND:

Indocyanine green (ICG) angiography is used to detect vessel compromise by the clip, residual aneurysms after clipping, or persistent aneurysm filling due to incomplete clipping. For ICG angiography, the microscope must be in a direct line-of-sight with the region of interest, limiting the identification of hidden arteries and dog-ear remnants.

OBJECTIVE:

To use a prototype endoscope for visualization of ICG fluorescence in hidden regions of the microsurgical field and evaluate its potential usefulness compared with microscopic ICG angiography (m-ICG-A) in a consecutive series of 30 aneurysms in 26 patients.

METHODS:

In selected cases, before and routinely after microsurgical clip application, m-ICG-A and endoscopic ICG angiography (e-ICG-A) were performed. The information gained by m-ICG-A was compared with that gained by e-ICG-A.

RESULTS:

E-ICG-A was technically feasible in all operations. Intra-arterial fluorescence could be visualized up to 10 times longer with the endoscope than with the microscope. The endoscope allowed a closer view on the fluorescent artery-aneurysm-complex. e-ICG-A provided more information than m-ICG-A in 11 operations (confirmation of unhindered blood flow in microscopically hidden vessels [n = 6], neck remnant identification [n = 2], neck remnant exclusion [n = 2], blood flow control in 2 distant clipped aneurysms [n = 1]). In 14 operations, identical information was obtained, and in 1 operation e-ICG-A was inferior because of trapped intra-aneurysmal fluorescence.

CONCLUSION:

In selected cases, e-ICG-A provides the neurosurgeon with information that cannot be obtained by m-ICG-A. e-ICG-A is capable of emerging as a useful adjunct in aneurysm surgery and has the potential to further improve operative results.

Indocyanine green videoangiography methodological variations: review

Indocyanine green videoangiography (ICGVA) procedures have become widespread within the spectrum of microsurgical techniques for neurovascular pathologies. We have conducted a review to identify and assess the impact of all of the methodological variations of conventional ICGVA applied in the field of neurovascular pathology that have been published to date in the English literature. A total of 18 studies were included in this review, identifying four primary methodological variants compared to conventional ICGVA: techniques based on the transient occlusion, intra-arterial ICG administration via catheters, use of endoscope system with a filter to collect florescence of ICG, and quantitative fluorescence analysis. These variants offer some possibilities for resolving the limitations of the conventional technique (first, the vascular structure to be analyzed must be exposed and second, vascular filling with ICG follows an additive pattern) and allow qualitatively superior information to be obtained during surgery. Advantages and disadvantages of each procedure are discussed. More case studies with a greater number of patients are needed to compare the different procedures with their gold standard, in order to establish these results consistently.

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.

Intraoperative laser speckle contrast imaging with retrospective motion correction for quantitative assessment of cerebral blood flow

Although multiple intraoperative cerebral blood flow (CBF) monitoring techniques are currently available, a quantitative method that allows for continuous monitoring and that can be easily integrated into the surgical workflow is still needed. Laser speckle contrast imaging (LSCI) is an optical imaging technique with a high spatiotemporal resolution that has been recently demonstrated as feasible and effective for intraoperative monitoring of CBF during neurosurgical procedures. This study demonstrates the impact of retrospective motion correction on the quantitative analysis of intraoperatively acquired LSCI images. LSCI images were acquired through a surgical microscope during brain tumor resection procedures from 10 patients under baseline conditions and after a cortical stimulation in three of those patients. The patient's electrocardiogram (ECG) was recorded during acquisition for postprocess correction of pulsatile artifacts. Automatic image registration was retrospectively performed to correct for tissue motion artifacts, and the performance of rigid and nonrigid transformations was compared. In baseline cases, the original images had [Formula: see text] noise across 16 regions of interest (ROIs). ECG filtering moderately reduced the noise to [Formula: see text], while image registration resulted in a further noise reduction of [Formula: see text]. Combined ECG filtering and image registration significantly reduced the noise to [Formula: see text] ([Formula: see text]). Using the combined motion correction, accuracy and sensitivity to small changes in CBF were improved in cortical stimulation cases. There was also excellent agreement between rigid and nonrigid registration methods (15/16 ROIs with [Formula: see text] difference). Results from this study demonstrate the importance of motion correction for improved visualization of CBF changes in clinical LSCI images.

Uncooled infrared camera for the noninvasive visualization of the vascular flow in an anastomotic vessel during neurological surgery: technical note

We herein present our experience to assess intraoperative confirmation of vascular patency with an uncooled infrared camera in extracranial–intracranial (EC-IC) bypass surgery. This camera had distinguishing characteristics, including its small size, light weight, and adequate temperature resolution (< 0.022 degrees). We used a simplified zoom germanium lens as a preliminary study to verify the potential of using this camera to assess the vascular flow of the end-to-side anastomosis model in rats. In addition, we evaluated the vascular flow in continuous clinical series using this infrared camera during EC-IC bypass in 14 patients (17 sides). This infrared camera offers real-time information on the vascular patency of end-to-side anastomosis vessels of all relevant diameters. The spatial resolution and image quality are satisfactory, and the procedure can be safely repeatable. We have shown that the infrared camera could be a new and feasible technology for intraoperative imaging of the vascular flow and is considered to be clinically useful during cerebrovascular surgery.

The utility and limitations of intraoperative near-infrared indocyanine green videoangiography in aneurysm surgery

OBJECTIVE

To analyze the clip repositioning rate and the correlation between indocyanine green (ICG) videoangiography and conventional postoperative digital subtraction angiography for completeness of aneurysm occlusion and parent and branching vessel compromise.

METHODS

This retrospective study included 112 patients with 126 aneurysms who underwent microsurgical clipping and ICG videoangiography during aneurysm surgery at a single center from January 2008 to June 2013. Age, gender, aneurysm size, location, and rupture status were included in the model for analysis.

RESULTS

In 10 patients (8%), ICG videoangiography resulted in clip repositioning during surgery. Discordance between ICG videoangiography and postoperative angiography was observed in 5 patients (4%). There was no significant difference of ICG videoangiography-postoperative angiography discordance between ruptured and unruptured aneurysms (P = 0.56). On multivariate analysis, patient age, gender, aneurysm size, and rupture status did not reach significance. Ophthalmic internal carotid artery aneurysms were more likely to have discordance compared with all other aneurysms (P = 0.04; odds ratio, 10.8; confidence interval, 1.5-75.94).

CONCLUSIONS

ICG videoangiography is a very useful modality for intraoperative assessment of the adequacy of aneurysmal obliteration and patency of parent and perforating vessels. However, ICG videoangiography is not absolutely reliable as a stand-alone method during clipping of ophthalmic artery aneurysms and can be complemented with intraoperative digital subtraction angiography. ICG videoangiography can be used either as an alternative or as a complementary technique to intraoperative digital subtraction angiography during aneurysm surgery.

Indocyanine green videoangiography "in negative": definition and usefulness in intracranial dural arteriovenous fistulae

BACKGROUND

Indocyanine green videoangiography (IGV) raises important limitations when we use it in vascular pathology, especially in cases with arterialization of the venous system such as arteriovenous malformations and fistulae.

OBJECTIVE

Our objective was to provide a simple procedure that overcomes the limitations of conventional IGV. We define IGV in negative (IGV-IN), so-called because, in its first phase, the vessel to analyze is clipped, and we report 3 cases of intracranial dural arteriovenous fistulae treated with this procedure.

METHODS

In 2011, we applied IGV-IN to 3 patients at our center with Borden type III intracranial arteriovenous fistulae.

RESULTS

In all 3 cases, IGV-IN enabled both diagnosis and post-dural arteriovenous fistula exclusion control in 1 integrated procedure no longer than 1 minute, requiring only 1 visualization.

CONCLUSION

IGV-IN is an improvement over the conventional IGV method and is able to provide more information in a shorter period of time. It is an intuitive and highly visual procedure, and, more importantly, it is reversible. Studies with larger samples are necessary to determine whether IGV-IN can further reduce the need for postoperative digital subtraction angiography.

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.

High cervical arteriovenous fistulas fed by dural and spinal arteries and draining into a single medullary vein: report of 3 cases

OBJECT

The authors previously reported a case of complex arteriovenous fistula (AVF) at C-1 with multiple dural and spinal feeders that were linked with a common medullary venous channel. The purpose of the present study was to collect similar cases and analyze their angioarchitecture to gain a better understanding of this malformation.

METHODS

Three such cases, affecting 2 males and 1 female in their 60s who had presented with hematomyelia (2) or progressive myelopathy (1), were treated surgically, and the operative findings from all 3 cases were compared using digital subtraction angiography (DSA) to determine the angioarchitecture.

RESULTS

The C-1 and C-2 radicular arteries and anterior and posterior spinal arteries supplied feeders to a single medullary draining vein in various combinations and via various routes. The drainage veins ran along the affected ventral nerve roots and lay ventral to the spinal cord. The sites of shunting to the vein were multiple: dural, along the ventral nerve root in the subarachnoid space, and on the spinal cord, showing a vascular structure typical of dural AVF, that is, a direct arteriovenous shunt near the spinal root sleeve fed by one or more dural arteries and ending in a single draining vein, except for intradural shunts fed by feeders from the spinal arteries. In 2 cases with hemorrhagic onset the drainer flowed rostrally, and in 1 case associated with congestive myelopathy the drainer flowed both rostrally and caudally. Preoperative determination of the shunt sites and feeding arteries was difficult because of complex recruitment of the feeders and multiple shunt sites. The angioarchitecture in these cases was clarified postoperatively by meticulous comparison of the DSA images and operative video. Direct surgical intervention led to a favorable outcome in all 3 cases.

CONCLUSIONS

A high cervical complex AVF has unique angioarchitectural characteristics different from those seen in the other spinal regions.

Treatment of complex neurovascular lesions: an interdisciplinary angio suite approach

OBJECTIVE

The objective of this study was to analyse our initial experience using an interdisciplinary angio suite approach to neurosurgical treatment of complex neurovascular lesions and expound technical feasibility and possible applications.

SUBJECTS

Six out of 451 patients with cranial or spinal neurovascular lesions were surgically treated in the angio suite (biplane angiographic system) during a 28-month observation period. Clinical baseline data, radiological and intraoperative findings as well as clinical and radiological outcome were assessed.

RESULTS

A ventral spinal perimedullary arteriovenous malformation, a ventral spinal perimedullary fistula, two diffuse frontal dural arteriovenous fistulas, a multifocal temporal arteriovenous malformation and a partially embolized fronto-temporo-basal dural arteriovenous fistula were successfully treated with angiographically confirmed complete occlusion and unimpaired neurological condition of the patients at the 12-month follow up.

CONCLUSION

This study demonstrates the feasibility of this approach and points out possible indications, namely ventrally located spinal lesions and diffuse, deep seated cranial lesions.