Current Indications for Indocyanine Green Angiography

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.

Intraoperative Measurement of Arterial Blood Flow in Aneurysm Surgery

Intraoperative flowmetry (IF) has been recently introduced during cerebral aneurysm surgery in order to obtain a safer surgical exclusion of the aneurysm. This study evaluates the usefulness of IF during surgery for cerebral aneurysms and compares the results obtained in the joined surgical series of Verona and Padua to the more recent results obtained at the neurosurgical department of Verona.In the first surgical series, between 2001 and 2010, a total of 312 patients were submitted to IF during surgery for cerebral aneurysm at the neurosurgical departments of Verona and Padua: 162 patients presented with subarachnoid hemorrhage (SAH) whereas 150 patients harbored unruptured aneurysms. In the second series, between 2011 and 2016, 112 patients were submitted to IF during surgery for cerebral aneurysm at the neurosurgical department of Verona; 24 patients were admitted for SAH, whereas 88 patients were operated on for unruptured aneurysms.Comparison of the baseline values in the two surgical series and the baseline values between unruptured and ruptured aneurysms showed no statistical differences between the two clinical series. Analysis of flowmetry measurements showed three types of loco-regional flow derangements: hyperemia after temporary arterial occlusion, redistribution of flow in efferent vessels after clipping, and low flow in patients with SAH-related vasospasm.IF provides real-time data about flow derangements caused by surgical clipping of cerebral aneurysm, thus enabling the surgeon to obtain a safer exclusion; furthermore, it permits the evaluation of other effects of clipping on the loco-regional blood flow. It is suggested that-in contribution with intraoperative neurophysiological monitoring-IF may now constitute the most reliable tool for increasing safety in aneurysm surgery.

Role of intraoperative indocyanine green video-angiography to identify small, posterior fossa arteriovenous malformations mimicking cavernous angiomas. Technical report and review of the literature on common features of these cerebral vascular malformations

OBJECTIVE

To illustrate the usefulness of intraoperative indocyanine green videoangiography (ICG-VA) to identify the nidus and feeders of a small cerebellar AVM resembling a cavernous hemangioma. To review the unique features regarding the overlay between these two vascular malformations and to highlight the importance to identify with ICG-VA, and treat accordingly, the arterial and venous vessels of the AVM.

METHODS

A 36-year old man presented with bilateral cerebellar hemorrhage. MRI was equivocal in showing an underlying vascular malformation but angiography demonstrated a small, Spetzler-Martin grade I AVM. Surgical resection of the AVM with the aid of intraoperative ICG-VA was performed. After hematoma evacuation, pre-resection ICG-VA did not reveal tortuous arterial and venous vessels in keeping with a typical AVM but rather an unusual blackberry-like image resembling a cavernous hemangioma, with tiny surrounding vessels. Such intraoperative appearance, which could also be the consequence of a "leakage" of fluorescent dye from the nidal pathological vessels, with absent blood-brain barrier, into the surrounding parenchymal pathological capillary network, is important to be recognized as an unusual AVM appearance.

RESULTS

Post-resection ICG-VA confirmed the AVM removal, as also shown by postoperative and 3-month follow-up DSAs.

CONCLUSIONS

Despite technical limitations associated with ICG-VA in post-hemorrhage AVMs, this case together with the intraoperative video, demonstrates the useful role of ICG-VA in identifying small AVMs with peculiar features.

A prospective study of microscope-integrated intraoperative fluorescein videoangiography during arteriovenous malformation surgery: preliminary results

OBJECT

The authors report on the use of a recently developed microscope-integrated fluorescent module using low-dose intravenous fluorescein for videoangiography during arteriovenous malformation (AVM) surgery.

METHODS

The authors analyzed the application of a low-dose intraoperative fluorescein in 4 consecutive patients undergoing AVM surgery. The ability to distinguish the associated vessels of the AVM from normal vessels and to assess the degree of AVM obliteration based on videoangiography of venous drainage was specifically analyzed.

RESULTS

All 4 patients underwent fluorescein angiography without complication. In each case, videoangiography confirmed recognition of feeding arteries and draining veins through the operating oculars under the fluorescent mode. In one case involving a large frontal AVM, videoangiography demonstrated mainly cortical veins on the surface of the AVM and alerted the senior author to first tackle the feeding arteries in the interhemispheric space. While evaluating the flow within the different draining veins after most of the AVM was disconnected, videoangiography also prioritized the order for disconnection of large draining veins to allow mobilization the AVM and exposure of the remaining deep arterial feeders. In the other 3 cases, videoangiography allowed easy recognition of the angioarchitecture of the AVMs, estimated its cortical boundaries, and most importantly, assessed the flow within the draining veins before their disconnection.

CONCLUSIONS

The authors found fluorescein videoangiography to be a useful adjunct in resection of AVMs. This technology offers the unique ability to visualize fluorescent vessels and nonfluorescent tissues in near-natural colors simultaneously and permits microsurgical manipulation of relevant structures under the fluorescent mode. Larger-scale studies are needed to establish its efficacy and wider applicability.

The “Squeezing Maneuver” in Microsurgical Clipping of Intracranial Aneurysms Assisted by Indocyanine Green Videoangiography

BACKGROUND:

Indocyanine green videoangiography (ICGV) is becoming routine in intracranial aneurysm surgery to assess intraoperatively both sac obliteration and vessel patency after clipping. However, ICGV-derived data have been reported to be misleading at times. We recently noted that a simple intraoperative maneuver, the “squeezing maneuver,” allows the detection of deceptive ICGV data on aneurysm exclusion and allows potential clip repositioning. The squeezing maneuver is based on a gentle pinch of the dome of a clipped aneurysm when ICGV documents its apparent exclusion.

OBJECTIVE:

To present the surgical findings and the clinical outcome of this squeezing maneuver.

METHODS:

Data from 23 consecutive patients affected by intracranial aneurysms who underwent the squeezing maneuver were analyzed retrospectively. The clip was repositioned in all cases when the dyeing of the sac was visualized after the maneuver.

RESULTS:

In 22% of patients, after an initial ICGV showing the aneurysm exclusion after clipping, the squeezing maneuver caused the prompt dyeing of the sac; in all cases, the clip was consequently repositioned. A calcification/atheroma of the wall/neck was predictive of a positive maneuver (P = .001). The aneurysm exclusion rate at postoperative radiological findings was 100%.

CONCLUSION:

With the limits of our small series, the squeezing maneuver appears helpful in the intraoperative detection of misleading ICGV data, mostly when dealing with aneurysms with atheromatic and calcified walls.

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.

Modern intraoperative imaging modalities for the vascular neurosurgeon treating intracerebral hemorrhage

This paper reviews the current intraoperative imaging tools that are available to assist neurosurgeons in the treatment of intracerebral hemorrhage (ICH). This review shares the authors' experience with each modality and discusses the advantages, potential limitations, and disadvantages of each. Surgery for ICH is directed at blood clot removal, reduction of intracranial pressure, and minimization of secondary damage associated with hematoma breakdown products. For effective occlusion and safe obliteration of vascular anomalies associated with ICH, vascular neurosurgeons today require a thorough understanding of the various intraoperative imaging modalities available for obtaining real-time information. Use of one or more of these modalities may improve the surgeon's confidence during the procedure, the patient's safety during surgery, and surgical outcome. The modern techniques discussed include 1) indocyanine green-based video angiography, which provides real-time information based on high-quality images showing the residual filling of vascular pathological entities and the patency of blood vessels of any size in the surgical field; and 2) intraoperative angiography, which remains the gold standard intraoperative diagnostic test in the surgical management of cerebral aneurysms and arteriovenous malformations. Hybrid procedures, providing multimodality image-guided surgeries and combining endovascular with microsurgical strategies within the same surgical session, have become feasible and safe. Microdoppler is a safe, noninvasive, and reliable technique for evaluation of hemodynamics of vessels in the surgical field, with the advantage of ease of use. Intraoperative MRI provides an effective navigation tool for cavernoma surgery, in addition to assessing the extent of resection during the procedure. Intraoperative CT scanning has the advantage of very high sensitivity to acute bleeding, thereby assisting in the confirmation of the extent of hematoma evacuation and the extent of vascular anomaly resection. Intraoperative ultrasound aids navigation and evacuation assessment during intracerebral hematoma evacuation surgeries. It supports the concept of minimally invasive surgery and has undergone extensive development in recent years, with the quality of ultrasound imaging having improved considerably. Image-guided therapy, combined with modern intraoperative imaging modalities, has changed the fundamentals of conventional vascular neurosurgery by presenting real-time visualization of both normal tissue and pathological entities. These imaging techniques are important adjuncts to the surgeon's standard surgical armamentarium. Familiarity with these imaging modalities may help the surgeon complete procedures with improved safety, efficiency, and clinical outcome.

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 < .001), ruptured aneurysm (P < .001), and increasing number of vessels injected (P < .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 > 8% of cases. Easy access to an angiographer and routine use of IOA are important factors contributing to procedural safety and efficacy.