Prospective evaluation of surgical microscope—integrated intraoperative near-infrared indocyanine green videoangiography during aneurysm surgery

Surgical Treatment of 127 Anterior Choroidal Artery Aneurysms A Cohort Study of Resultant Ischemic Complications

BACKGROUND:

The anterior choroidal artery (AChA) supplies important areas of the nervous system, particularly the posterior limb of the internal capsule and optic radiation. Treatment of AChA aneurysms poses particular challenges because of the complex anatomy of the aneurysm associated with the relatively small diameter of AChAs, making preservation of the parent vessel during clip ligation or endosaccular coiling challenging.

OBJECTIVE:

To investigate the incidence and features of ischemia in treatment of AChA aneurysms.

METHODS:

A prospectively maintained database of patients who underwent treatment of aneurysms from 1985 to 2011 was queried to find patients with AChA aneurysms. Age, sex, Hunt and Hess grade, treatment modality, and complications were analyzed by use of the unpaired Student t test and Fisher exact test.

RESULTS:

One hundred twenty-two patients harbored 127 AChA aneurysms, and 67% (82 of 122) had multiple aneurysms. Treatment included 112 microsurgical clip ligations, 8 endosaccular coil embolizations, 5 aneurysmal wrappings, and 2 surgical explorations. Complications developed in 53% (67 of 127) of AChA aneurysms. Postoperative ischemia occurred in 12% (15 of 127) of treated aneurysms. The number of temporary clip applications was most closely associated with postoperative ischemia. Glasgow Outcome Scale scores of 4 or 5 were obtained by 78% at discharge, 89% at 6 months, and 85% at 1 year.

CONCLUSION:

The ischemic complication rate from surgical treatment of AChA aneurysms is most closely associated with higher frequency of temporary clip applications for proximal control and may be lower than previously reported. Supplementary intraoperative tools and limitation of vessel manipulation should be used to improve outcomes.

The risk of seizures during the in-hospital admission for surgical or endovascular treatment of unruptured intracranial aneurysms

Few studies detail the risk of in-hospital seizures following elective surgical or endovascular treatment of unruptured intracranial aneurysms (UIA). We compared the peri-procedural seizure incidence for clipping and coiling of UIA. A retrospective cohort study using the Australian National Hospital Morbidity Database from 1998 to 2008 was conducted. Treatment modalities were compared for the combined primary end point related to seizure. Putative risk factors were investigated with univariate and multivariate logistic regression analysis to identify independent predictors of outcome. A total of 5922 hospitalisations for UIA (3098 clipping, 2824 coiling) were identified. Overall, surgery was associated with a 2.7% (95% confidence interval [CI] 2.2-3.4) incidence of peri-operative seizures, compared to a 0.6% (95% CI 0.4-1.0) incidence following endovascular treatment (adjusted odds ratio [OR] 4.40; 95% CI 2.64-7.33; p<0.001). The incidences of seizures declined over the 11 year study period in both treatment groups, from 4.2% to 2.0% for surgery and from 2.8% to 0.3% for endovascular. Haemorrhagic complication with intracerebral haemorrhage predicted occurrence of a seizure (OR 3.41; 95% CI 1.20-9.66; p=0.021), whereas endovascular coiling was associated with a better seizure outcome (OR 0.23; 95% CI 0.14-0.39; p<0.001). Overall, elective surgical treatment of UIA is associated with a higher risk of seizure occurrence compared to endovascular coiling. Contrary to conventional thinking, the risk of seizures following endovascular treatment is not entirely absent. Current recommendations must be considered in relation to the issue of driving after elective intracranial aneurysm treatment.

Directional Intraoperative Doppler Ultrasonography During Surgery on Cranial Dural Arteriovenous Fistulas

BACKGROUND:

Directional intraoperative Doppler (dioDoppler) ultrasonography is well established as a tool in the surgery of intracranial aneurysms and cerebral arteriovenous malformations. The literature provides little information about the possible usefulness of this method during surgery on cranial dural arteriovenous fistulas (dAVFs).

OBJECTIVE:

To present our experience with the use of dioDoppler during surgery on cranial dAVFs.

METHODS:

All patients undergoing craniotomy for cranial dAVF from January 2007 to October 2012 in which dioDoppler was used were included in the study. We reviewed patient records, operating protocols, radiological images, dioDoppler files, and intraoperative videos.

RESULTS:

During the study period, 12 patients with cranial dAVFs underwent surgical treatment facilitated by dioDoppler. Four patients were operated on acutely for cerebral bleeds, and 8 patients were treated for various cerebral symptoms and the assumption of a significant risk for intracranial bleed. Three advantages of dioDoppler were unequivocal identification of veins with cortical/deep venous reflux from the fistula, verification of completeness of occlusion of the fistula, and identification of dural arterial feeders not visualized under the microscope.

CONCLUSION:

Reviewing our experience, we found that dioDoppler sonography is an easy, safe, effective, reliable, and instantaneous tool during surgery on cranial dAVFs.

Distal middle cerebral artery aneurysm: A proposition of microsurgical management

OBJECTIVES

Based on a cohort of patients treated on distal middle cerebral artery (MCA) aneurysm by microsurgical approach, the objectives were to assess the following: the postoperative functional outcome, study the causes of early neurological deterioration and to determine the predictive factors of favourable outcome.

PATIENTS AND METHODS

From a neurovascular prospective database, this retrospective longitudinal study included all the patients treated for cerebral aneurysm located on the distal segment of the MCA over two decades (January 1990-December 2011). The patients were all treated by microsurgical clipping exclusion. Any aneurysm was associated to infectious angiopathy. Data were retrieved from the patient's medical charts. The outcome was analysed twice: during the immediate postoperative period and at 6 months according to the modified Rankin scale. The relative risk was estimated for each variable and the prognostic factors were assessed using a multivariate logistic regression model (P<0.05).

RESULTS

Twenty-eight patients, mean age 40±13.3 years (median: 43 years; range 6-70 years) were divided into the ruptured group (n=20) and unruptured group (n=8). In the ruptured group, the initial clinical status was good (WFNS I-III) in 12 patients (60%) and poor in eight (40%) with an intracerebral haematoma (ICH) in 11 (55%). For both groups, the aneurysm location on the distal MCA decreased at a rate from 64.8% of the insular segment to 25% of the opercular then 10.7% to the cortical. During the hospital stay, neurological deterioration occurred in 16 patients (57.2%). The diagnosed causes were cerebral ischaemia in 10 (35.6%), initial ICH in three (10.7%), hydrocephalus in two (7.1%) and epilepsy in one (7.1%). At 6 months, a favourable outcome (mRS 0-2) was observed in 19 patients (68.1%), a definitive morbidity in seven (24.9%) and death in two (7.2%). Based on the prognostic factors, only the absence of immediate postoperative neurological deterioration was identified as significant for a favourable outcome.

CONCLUSION

These rare cerebral aneurysms resulted in a high proportion of poor initial status related to a frequent ICH. Cerebral ischaemia was a major cause of the immediate neurological deterioration and the absence of immediate neurological deterioration was the single identified prognostic factor.

Selective-targeted extra-intracranial bypass surgery in complex middle cerebral artery aneurysms: correctly identifying the recipient artery using indocyanine green videoangiography

BACKGROUND

Treatment of complex middle cerebral artery (MCA) aneurysms often requires vessel sacrifice or prolonged temporary occlusion with extra- to intracranial (EC-IC) bypass to preserve perfusion. A crucial surgical step is the identification of the bypass recipient artery matching the distal territory of the involved vessel.

OBJECTIVE

To report about the feasibility and efficiency of an indocyanine green videoangiography (ICG-VA) assisted technique for identification of cortical recipient vessels to perform selective-targeted EC-IC bypass.

METHODS

The proposed technique is based on the analysis of differences in the timing of filling of M4 vessels seen on serial ICG-VAs. A delayed fluorescence can be visualized either primarily on a baseline ICG-VA or secondarily on an ICG-VA performed during temporary occlusion of the involved MCA branch. M4 branches presenting delayed fluorescence represent suitable bypass recipient arteries. We report 7 consecutive patients treated for complex MCA aneurysms with selective-targeted EC-IC bypass.

RESULTS

Application of the proposed technique permitted the correct identification of recipient arteries (cortical branches of the involved MCA segment) in all patients. The cortex distal to the occlusion filled concomitantly on ICG-VA at the end of surgery. All patients underwent successful treatment of the aneurysm, including a cortical bypass. There were no ischemic complications, and a favorable clinical outcome was achieved in all patients (modified Rankin Scale at follow-up ≤ modified Rankin Scale preoperative).

CONCLUSION

The proposed ICG-VA-based technique enables reliable and accurate identification of the cortical recipient artery and eliminates the risk of erroneous revascularization of noninvolved territories.

Value of indocyanine green videoangiography in deciding the completeness of cerebrovascular surgery

OBJECTIVE

Recently, microscope-integrated near infrared indocyanine green videoangiography (ICG-VA) has been widely used in cerebrovascular surgery because it provides real-time high resolution images. In our study, we evaluate the efficacy of intraoperative ICG-VA during cerebrovascular surgery.

METHODS

Between August 2011 and April 2012, 188 patients with cerebrovascular disease were surgically treated in our institution. We used ICG-VA in that operations with half of recommended dose (0.2 to 0.3 mg/kg). Postoperative digital subtraction angiography and computed tomography angiography was used to confirm anatomical results.

RESULTS

Intraoperative ICG-VA demonstrated fully occluded aneurysm sack, no neck remnant, and without vessel compromise in 119 cases (93.7%) of 127 aneurysms. Eight clipping (6.3%) of 127 operations were identified as an incomplete aneurysm occlusion or compromising vessel after ICG-VA. In 41 (97.6%) of 42 patients after carotid endarterectomy, the results were the same as that of postoperative angiography with good patency. One case (5.9%) of 17 bypass surgeries was identified as a nonfunctioning anastomosis after ICG-VA, which could be revised successfully. In the two patients of arteriovenous malformation, ICG-VA was useful for find the superficial nature of the feeding arteries and draining veins.

CONCLUSION

ICG-VA is simple and provides real-time information of the patency of vessels including very small perforators within the field of the microscope and has a lower rate of adverse reactions. However, ICG-VA is not a perfect method, and so a combination of monitoring tools assures the quality of cerebrovascular surgery.

Evaluation of a completely robotized neurosurgical operating microscope

BACKGROUND

Operating microscopes are essential for most neurosurgical procedures. Modern robot-assisted controls offer new possibilities, combining the advantages of conventional and automated systems.

OBJECTIVE

We evaluated the prototype of a completely robotized operating microscope with an integrated optical coherence tomography module.

METHODS

A standard operating microscope was fitted with motors and control instruments, with the manual control mode and balance preserved. In the robot mode, the microscope was steered by a remote control that could be fixed to a surgical instrument. External encoders and accelerometers tracked microscope movements. The microscope was additionally fitted with an optical coherence tomography-scanning module.

RESULTS

The robotized microscope was tested on model systems. It could be freely positioned, without forcing the surgeon to take the hands from the instruments or avert the eyes from the oculars. Positioning error was about 1 mm, and vibration faded in 1 second. Tracking of microscope movements, combined with an autofocus function, allowed determination of the focus position within the 3-dimensional space. This constituted a second loop of navigation independent from conventional infrared reflector-based techniques. In the robot mode, automated optical coherence tomography scanning of large surface areas was feasible.

CONCLUSION

The prototype of a robotized optical coherence tomography-integrated operating microscope combines the advantages of a conventional manually controlled operating microscope with a remote-controlled positioning aid and a self-navigating microscope system that performs automated positioning tasks such as surface scans. This demonstrates that, in the future, operating microscopes may be used to acquire intraoperative spatial data, volume changes, and structural data of brain or brain tumor tissue.

Intraoperative neurophysiological monitoring of extracranial-intracranial bypass procedures

OBJECT

Intraoperative neurophysiological monitoring (IONM) represents an established tool in neurosurgery to increase patient safety. Its application, however, is controversial. Its use has been described as helpful in avoiding neurological deterioration during intracranial aneurysm surgery. Its impact on extracranial-intracranial (EC-IC) bypass surgery involving parent artery occlusion for the treatment of complex aneurysms has not yet been studied. The authors therefore sought to evaluate the effects of IONM on patient safety, the surgeon's intraoperative strategies, and functional outcome of patients after cerebral bypass surgery. Intraoperative neurophysiological monitoring results were compared with those of intraoperative blood flow monitoring to assess bypass graft perfusion.

METHODS

Compound motor action potentials (CMAPs) were generated using transcranial electrical stimulation in patients undergoing EC-IC bypass surgery. Preoperative and postoperative motor function was analyzed. To assess graft function, intraoperative flowmetry and indocyanine green fluorescence angiography were performed. Special care was taken to compare the relevance of electrophysiological and blood flow monitoring in the detection of critical intraoperative ischemic episodes.

RESULTS

The study included 31 patients with 31 aneurysms and 1 bilateral occlusion of the internal carotid arteries, undergoing 32 EC-IC bypass surgeries in which radial artery or saphenous vein grafts were used. In 11 cases, 15 CMAP events were observed, helping the surgeon to determine the source of deterioration and to react to it: 14 were reversible and only 1 showed no recovery. In all cases, blood flow monitoring showed good perfusion of the bypass grafts. There were no false-negative results in this series. New postoperative motor deficits were transient in 1 case, permanent in 1 case, and not present in all other cases.

CONCLUSIONS

Intraoperative neurophysiological monitoring is a helpful tool for continuous functional monitoring of patients undergoing large-caliber vessel EC-IC bypass surgery. The authors' results suggest that continuous neurophysiological monitoring during EC-IC bypass surgery has relevant advantages over flow-oriented monitoring techniques such as intraoperative flowmetry or indocyanine green-based angiography.

The Barrow Ruptured Aneurysm Trial: 3-year results

OBJECT

The authors report the 3-year results of the Barrow Ruptured Aneurysm Trial (BRAT). The objective of this ongoing randomized trial is to compare the safety and efficacy of microsurgical clip occlusion and endovascular coil embolization for the treatment of acutely ruptured cerebral aneurysms and to compare functional outcomes based on clinical and angiographic data. The 1-year results have been previously reported.

METHODS

Two-hundred thirty-eight patients were assigned to clip occlusion and 233 to coil embolization. There were no anatomical exclusions. Crossovers were allowed based on the treating physician's determination, but primary outcome analysis was based on the initial assignment to treatment modality. Patient outcomes were assessed independently using the modified Rankin Scale (mRS). A poor outcome was defined as an mRS score>2. At 3 years' follow-up 349 patients who had actually undergone treatment were available for evaluation. Of the 170 patients who had been originally assigned to coiling, 64 (38%) crossed over to clipping, whereas 4 (2%) of 179 patients assigned to surgery crossed over to clipping.

RESULTS

The risk of a poor outcome in patients assigned to clipping compared with those assigned to coiling (35.8% vs 30%) had decreased from that observed at 1 year and was no longer significant (OR 1.30, 95% CI 0.83-2.04, p=0.25). In addition, the degree of aneurysm obliteration (p=0.0001), rate of aneurysm recurrence (p=0.01), and rate of retreatment (p=0.01) were significantly better in the group treated with clipping compared with the group treated with coiling. When outcomes were analyzed based on aneurysm location (anterior circulation, n=339; posterior circulation, n=69), there was no significant difference in the outcomes of anterior circulation aneurysms between the 2 assigned groups across time points (at discharge, 6 months, 1 year, or 3 years after treatment). The outcomes of posterior circulation aneurysms were significantly better in the coil group than in the clip group after the 1st year of follow-up, and this difference persisted after 3 years of follow-up. However, while aneurysms in the anterior circulation were well matched in their anatomical location between the 2 treatment arms, this was not the case in the posterior circulation where, for example, 18 of 21 posterior inferior cerebellar artery aneurysms were in the clip group.

CONCLUSIONS

Based on mRS scores at 3 years, the outcomes of all patients assigned to coil embolization showed a favorable 5.8% absolute difference compared with outcomes of those assigned to clip occlusion, although this difference did not reach statistical significance (p=0.25). Patients in the clip group had a significantly higher degree of aneurysm obliteration and a significantly lower rate of recurrence and retreatment. In post hoc analysis examining only anterior circulation aneurysms, no outcome difference between the 2 treatment cohorts was observed at any recorded time point. CLINICAL TRIAL REGISTRATION NO.: NCT01593267 ( ClinicalTrials.gov ).

Patterns in neurosurgical adverse events: open cerebrovascular neurosurgery

OBJECT

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

METHODS

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

RESULTS

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

DISCUSSION

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

Semiquantitative analysis of indocyanine green videoangiography for cortical perfusion assessment in superficial temporal artery to middle cerebral artery anastomosis

BACKGROUND

Postoperative hyperperfusion may lead to severe neurological complications after superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. However, there are no reliable modalities to predict the occurrence of postoperative hyperperfusion during surgery. The purpose of this study is to evaluate whether a semiquantitative analysis of indocyanine green (ICG) videoangiography could be useful in predicting postoperative hyperperfusion after STA-MCA anastomosis.

METHODS

This study included seven patients who underwent STA-MCA anastomosis due to occlusive carotid artery diseases. During surgery, ICG videoangiography was performed before and after bypass procedures, and ICG intensity-time curves were semiquantitatively analyzed to evaluate hemodynamic changes by calculating maximum intensity, time to peak (TTP), and blood flow index (BFI).

RESULTS

Maximum intensity significantly increased from 252.6 ± 132.5 to 351.7 ± 151.9 after bypass (p < 0.001). TTP was significantly shortened from 12.9 ± 4.4 s to 9.8 ± 3.7 s (p < 0.001). Furthermore, BFI significantly increased from 33.9 ± 28.1 to 74.6 ± 88.4 (p < 0.05). Postoperative hyperperfusion was observed in five of seven patients 1 day after surgery. The ratio of BFI before and after bypass procedures was significantly higher in patients with postoperative hyperperfusion than those without, 2.5 ± 1.1 and 1.5 ± 0.4, respectively (p = 0.013).

CONCLUSIONS

These findings suggest that semiquantitative analysis of ICG videoangiography is helpful in predicting occurrence of hyperperfusion after STA-MCA anastomosis in patients with occlusive carotid artery diseases.

Technical principles and neurosurgical applications of fluorescein fluorescence using a microscope-integrated fluorescence module

BACKGROUND

Fluorescent technology has recently become a valuable tool in the surgical management of neoplastic and vascular lesions. The availability of microscope-integrated fluorescent modules has facilitated incorporation of this technology within the microsurgical workflow. The currently available microscope integrated modules use 5-aminolevulinic acid (5-ALA) and indocyanine green (ICG) as fluorophores.

METHODS

Fluorescein sodium is a fluorescent molecule that has been used specifically in ophthalmology for the treatment of retinal angiography. A new microscope-integrated fluorescent module has been recently developed for fluorescein. We employed this technology to maximize resection of tumors and perform intraoperative angiography to guide microsurgical management of aneurysms and arteriovenous malformations.

RESULTS

Fluorescein fluorescence allows the surgeon to appreciate fluorescent structures through the oculars while visualizing non-fluorescent tissues in near natural colors. Therefore, the operator can proceed with microsurgery under the fluorescent mode. We present three representative cases in which the use of fluorescein fluorescence was found useful in the surgeon's decision making during surgery.

CONCLUSIONS

The applications of this new microscope-integrated fluorescent module are multiple, and include vascular and oncologic neurosurgery. Further clinical investigations with large patient cohorts are needed to fully establish the role of this new technology.

Use of microscope-integrated near-infrared indocyanine green videoangiography in the surgical treatment of intramedullary cavernous malformations: report of 8 cases

OBJECT

The characteristics and efficacy of indocyanine green (ICG) videoangiography in cavernous malformation (CM) have not been fully elucidated. The purpose of this paper is to examine the potential utility of ICG videoangiography in the surgical treatment of intramedullary CMs.

METHODS

The authors conducted a retrospective review of 8 cases involving 5 men and 3 women who had undergone surgery for intramedullary CM between January 2008 and July 2011. All patients were evaluated by means of MRI. The MRI findings and clinical history in all cases suggested intramedullary CM as a preoperative diagnosis. In 2 of 8 cases, dilated venous structures associated with CMs were demonstrated. In one of these cases, there were coexisting extramedullary CMs. Intraoperatively, ICG fluorescence was observed for 5 minutes using microscope-integrated videoangiography.

RESULTS

In all 8 cases, intra- and extramedullary CMs were seen as avascular areas on ICG videoangiography. Indocyanine green videoangiography helped surgeons to localize and predict margins of the lesions before performing myelotomy. Importantly, in the cases with associated venous anomalies, ICG videoangiography was useful in delineating and preserving the venous structures. In extramedullary CMs located dorsal to the spinal cord, gradual ICG infiltration was seen, starting at 110 seconds and maximal at 210 seconds after injection. Postoperative MRI confirmed total removal of the lesions in all cases, and subsequent recovery of all patients was uneventful.

CONCLUSIONS

Indocyanine green videoangiography provided useful information with regard to the detection of lesion margins by demonstrating intramedullary CMs as avascular areas. In cases associated with venous anomalies, ICG contributed to safe and complete removal of the CMs by visualizing the venous structure. In extramedullary CMs, ICG videoangiography demonstrated the characteristic of slow blood flow within CMs.

Flash fluorescence with indocyanine green videoangiography to identify the recipient artery for bypass with distal middle cerebral artery aneurysms: operative technique

BACKGROUND

Distal middle cerebral artery (MCA) aneurysms frequently have nonsaccular morphology that necessitates trapping and bypass. Bypasses can be difficult because efferent arteries lie deep in the opercular cleft and may not be easily identifiable.

OBJECTIVE

We introduce the "flash fluorescence" technique, which uses videoangiography with indocyanine green (ICG) dye to identify an appropriate recipient artery on the cortical surface for the bypass, enabling a more superficial and easier anastomosis.

METHODS

Flash fluorescence requires 3 steps: (1) temporary clip occlusion of the involved afferent artery; (2) videoangiography demonstrating fluorescence in uninvolved arteries on the cortical surface; and (3) removal of the temporary clip with flash fluorescence in the involved efferent arteries on the cortical surface, thereby identifying a recipient. Alternatively, temporary clips can occlude uninvolved arteries, and videoangiography will demonstrate initial fluorescence in efferent arteries during temporary occlusion and flash fluorescence in uninvolved arteries during reperfusion.

RESULTS

From a consecutive series of 604 MCA aneurysms treated microsurgically, 22 (3.6%) were distal aneurysms and 11 required a bypass. The flash fluorescence technique was used in 3 patients to select the recipient artery for 2 superficial temporal artery-to-MCA bypasses and 1 MCA-MCA bypass. The correct recipient was selected in all cases.

CONCLUSION

The flash fluorescence technique provides quick, reliable localization of an appropriate recipient artery for bypass when revascularization is needed for a distal MCA aneurysm. This technique eliminates the need for extensive dissection of the efferent artery and enables a superficial recipient site that makes the anastomosis safer, faster, and less demanding.

Endoscopy in aneurysm surgery

BACKGROUND

Surgical clipping with complete occlusion of the aneurysm and preservation of parent, branching, and perforating vessels remains the most definitive treatment for intracranial aneurysms.

OBJECTIVE

To evaluate the benefit of endoscopic application during microsurgical procedures in a retrospective study.

METHODS

One hundred eighty aneurysms were microsurgically treated in 124 operations. Three different applications of endoscopic visualization were used, depending on the respective requirements: inspection before clipping, clipping under endoscopic view, and postclipping evaluation.

RESULTS

Of 1380 aneurysms, 292 procedures were done with application of the endoscope. Of these 292, a complete data set, including video recording of the procedures for retrospective evaluation, was available in 180 cases. In these, the endoscope provided a favorable enhancement of the visual field, particularly in complex or deep-seated lesions. No adverse effects were observed. Before clipping, the endoscope was used to gain additional topographic information in 150 of 180 cases (83%). Clipping under endoscopic view was performed in 4 cases. After clipping, endoscopic inspection was performed in 130 of 180 procedures. Depending on the endoscopic findings, rearrangement of the applied clip or additional clipping was found to be necessary in 26 of 130 cases (20.0%).

CONCLUSION

Endoscopic enhancement of the visual field provided by the endoscope before, during, and after microsurgical aneurysm occlusion may be a safe and effective application to increase the quality of treatment. Although unexpected findings concerning completeness of aneurysm occlusion and compromise of involved vessels could be diminished by endoscopic assessment, total prevention was not accomplished.

European Stroke Organization guidelines for the management of intracranial aneurysms and subarachnoid haemorrhage

BACKGROUND

Intracranial aneurysm with and without subarachnoid haemorrhage (SAH) is a relevant health problem: The overall incidence is about 9 per 100,000 with a wide range, in some countries up to 20 per 100,000. Mortality rate with conservative treatment within the first months is 50-60%. About one third of patients left with an untreated aneurysm will die from recurrent bleeding within 6 months after recovering from the first bleeding. The prognosis is further influenced by vasospasm, hydrocephalus, delayed ischaemic deficit and other complications. The aim of these guidelines is to provide comprehensive recommendations on the management of SAH with and without aneurysm as well as on unruptured intracranial aneurysm.

METHODS

We performed an extensive literature search from 1960 to 2011 using Medline and Embase. Members of the writing group met in person and by teleconferences to discuss recommendations. Search results were graded according to the criteria of the European Federation of Neurological Societies. Members of the Guidelines Committee of the European Stroke Organization reviewed the guidelines.

RESULTS

These guidelines provide evidence-based information on epidemiology, risk factors and prognosis of SAH and recommendations on diagnostic and therapeutic methods of both ruptured and unruptured intracranial aneurysms. Several risk factors of aneurysm growth and rupture have been identified. We provide recommendations on diagnostic work up, monitoring and general management (blood pressure, blood glucose, temperature, thromboprophylaxis, antiepileptic treatment, use of steroids). Specific therapeutic interventions consider timing of procedures, clipping and coiling. Complications such as hydrocephalus, vasospasm and delayed ischaemic deficit were covered. We also thought to add recommendations on SAH without aneurysm and on unruptured aneurysms.

CONCLUSION

Ruptured intracranial aneurysm with a high rate of subsequent complications is a serious disease needing prompt treatment in centres having high quality of experience of treatment for these patients. These guidelines provide practical, evidence-based advice for the management of patients with intracranial aneurysm with or without rupture. Applying these measures can improve the prognosis of SAH.

Multiple reimplantation technique for treatment of complex giant aneurysms of the middle cerebral artery: technical note

BACKGROUND

Giant middle cerebral artery (MCA) aneurysms are among the most challenging neurovascular lesions, especially when the M2 and M3 branches are incorporated into the aneurysm. Here we report on two cases with complex MCA aneurysms, in which double and triple arterial reimplantation of the efferent vessels into a saphenous vein graft (SVG) was applied to reconstruct the MCA tree, allowing final trapping of the aneurysm.

METHODS

In the first case, a 41-year-old woman presented with a partially thrombosed giant MCA aneurysm including three efferent branches. Two superior trunks were disconnected and reimplanted onto an SVG fed by the external carotid artery (ECA). Following anastomosis between the SVG and the inferior trunk, the aneurysm was trapped. The second case is a 67-year-old man with recurrent giant MCA aneurysm incorporating two efferent M2 branches. First, the superior trunk was reimplanted onto an SVG, then the SVG was anastomosed to the inferior trunk. Finally the afferent M1 was clipped. Intraoperative indocyanine green (ICG) videoangiography (FLOW 800) was used for studying bypass patency.

RESULTS

In both cases, successful bypass patency was demonstrated by ICG videoangiography. Postoperative digital subtraction angiography (DSA) confirmed bypass patency. The first case was discharged without any neurological deficit. The second case suffered from bleeding due to refilling of the aneurysm via the inferior M2. An additional clip was placed on the inferior M2 in a second step. The patient was discharged with weakness of the left arm.

CONCLUSION

Reconstructing an MCA bifurcation or trifurcation combining multiple arterial reimplantation is effective for treatment of selective cases of complex MCA aneurysms.

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

Object

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

Methods

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

Results

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

Conclusions

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

Uses and limitations of indocyanine green videoangiography for flow analysis in arteriovenous malformation surgery

Intra-operative indocyanine green (ICG) videoangiography is a useful addition to cerebrovascular neurosurgery. ICG videoangiography is useful in different phases of arteriovenous malformation (AVM) surgery. Additionally, it can be used to perform semi-quantitative flow analysis. We reviewed our initial assessment of 24 patients who underwent ICG videoangiography during AVM surgery to assess the utility and limitations of the technique as well as to demonstrate semi-quantitative flow analysis, a new capability of ICG videoangiography. Over the course of 3 years, we performed 49 ICG videoangiographies in 24 patients with AVM. In 85% of the pre-resection videos, ICG was useful in localising the arterial feeders, the draining veins and the nidus. Intra-resection ICG videos were recorded for eight of the 23 patients (the ICG from one patient was missing). Post-resection ICG videos were recorded for 14 out of the 23 patients, which were useful in confirming no evidence of nidus in the exposed resection cavity and an absence of flow in the main draining vein. Semi-quantitative flow analysis was performed in eight patients with superficial AVM. The average T(½) peak intensities (time to 50% of peak intensity) were 32 s, 33.5 s, and 35.6 s for the arterial feeder, the draining vein and normal cortex, respectively. The arteriovenous T(½) peak time was 1.5 s, and the arteriocortex T(½) peak time was 3.6 s. The T(½) peak fluorescence rates were 84 average intensity of fluorescence (AI)/s, 62.9 AI/s and 28.7 AI/s, for the arterial feeder, the draining vein and normal cortex, respectively. Only one patient of 23 (4.3%) showed residual AVM on post-operative digital subtraction angiography or CT angiography despite negative intra-operative ICG. ICG videoangiography is a useful addition to AVM surgery, but it has some limitations. Flow analysis is a new capability that allows for semi-quantitative AVM perfusion analysis.

The use of indocyanine green videoangiography to optimize the dural opening for intracranial parasagittal lesions

BACKGROUND

We describe our clinical experience with the use of indocyanine green (ICG) videoangiography to delineate the locations of the cortical draining veins before dural opening in 3 cases of parasagittal lesions. With this technique, the veins are marked through the dura, and then the dura can be opened precisely to avoid cortical venous injury.

OBJECTIVE

To demonstrate in a clinical series the adjunct use of intraoperative ICG angiography to optimize the dural opening for parasagittal lesions.

METHODS

We describe 3 cases of parasagittal lesions, 2 meningiomas, and 1 arteriovenous malformation treated using the described technique.

RESULTS

Once the dura had been exposed, ICG at a dose of 0.25 mg/kg was injected into the patient's peripheral vein as a bolus. When the dye reached the illuminated field of interest, ICG fluorescence was induced by the use of a light source with a wave-length ICG absorption band. Thereafter, the dural cortical veins were marked through the dura and precisely opened, avoiding cortical venous injury.

CONCLUSION

Indocyanine green video angiography is a safe, fast, inexpensive, and accurate investigation that allows the surgeon to strategically plan and protect important parasagittal dural venous drainage during craniotomy.

Evaluation of serial intraoperative surgical microscope-integrated intraoperative near-infrared indocyanine green videoangiography in patients with cerebral arteriovenous malformations

BACKGROUND

With the use of indocyanine green (ICG) as a novel fluorescent dye, fluorescence angiography has recently reemerged as a viable option.

OBJECTIVE

To show the result of ICG videoangiography in cases of cerebral arteriovenous malformations.

METHODS

Twenty-seven ICG videoangiography procedures were performed in 11 patients with cerebral arteriovenous malformations. Intraoperative digital subtraction angiography (DSA) was performed 27 times in these patients. The timing of intraoperative DSA was before dissection, after clipping of feeders, and after dissection of the nidus.

RESULTS

The procedures were performed in 4.7 ± 1.4 minutes (mean ± SD; n = 27 minutes), whereas intraoperative digital subtraction angiography was performed for a mean of 16.6 ± 3.8 minutes (n = 27 minutes). In predissection studies, feeders were visualized by ICG in 3 of 9 cases. The nidus was visualized in all 9 cases, and drainers were visualized in 8. Intraoperative DSA visualized the feeders, nidus, and drainers in all 9 cases. After clipping of feeders, ICG videoangiography showed flow reduction of the nidus in 7 of 7 cases. Intraoperative DSA also showed that finding in 9 of 9 cases. After total dissection of the nidus, all cases disclosed that the drainers were without ICG filling. Intraoperative DSA also showed that result in all of the cases. Unexpected residual nidus was not visualized in our series with either method.

CONCLUSION

We found that ICG videoangiography is helpful for resecting cerebral arteriovenous malformation. It is especially effective in visualizing the nidus and superficial drainers, as well as changes in flow after clipping or coagulating of feeders.

Microscope-integrated quantitative analysis of intraoperative indocyanine green fluorescence angiography for blood flow assessment: first experience in 30 patients

BACKGROUND

Intraoperative measurements of cerebral blood flow are of interest during vascular neurosurgery. Near-infrared indocyanine green (ICG) fluorescence angiography was introduced for visualizing vessel patency intraoperatively. However, quantitative information has not been available.

OBJECTIVE

To report our experience with a microscope with an integrated dynamic ICG fluorescence analysis system supplying semiquantitative information on blood flow.

METHODS

We recorded ICG fluorescence curves of cortex and cerebral vessels using software integrated into the surgical microscope (Flow 800 software; Zeiss Pentero) in 30 patients undergoing surgery for different pathologies. The following hemodynamic parameters were assessed: maximum intensity, rise time, time to peak, time to half-maximal fluorescence, cerebral blood flow index, and transit times from arteries to cortex.

RESULTS

For patients without obvious perfusion deficit, maximum fluorescence intensity was 177.7 arbitrary intensity units (AIs; 5-mg ICG bolus), mean rise time was 5.2 seconds (range, 2.9-8.2 seconds; SD, 1.3 seconds), mean time to peak was 9.4 seconds (range, 4.9-15.2 seconds; SD, 2.5 seconds), mean cerebral blood flow index was 38.6 AI/s (range, 13.5-180.6 AI/s; SD, 36.9 seconds), and mean transit time was 1.5 seconds (range, 360 milliseconds-3 seconds; SD, 0.73 seconds). For 3 patients with impaired cerebral perfusion, time to peak, rise time, and transit time between arteries and cortex were markedly prolonged (>20, >9 , and >5 seconds). In single patients, the degree of perfusion impairment could be quantified by the cerebral blood flow index ratios between normal and ischemic tissue. Transit times also reflected blood flow perturbations in arteriovenous fistulas.

CONCLUSION

Quantification of ICG-based fluorescence angiography appears to be useful for intraoperative monitoring of arterial patency and regional cerebral blood flow.

Spinal epidural arteriovenous hemangioma mimicking lumbar disc herniation

A spinal epidural hemangioma is rare. In this case, a 51 year-old female patient had low back pain and right thigh numbness. She was initially misdiagnosed as having a ruptured disc with possible sequestration of granulation tissue formation due to the limited number of spinal epidural hemangiomas and little-known radiological findings. Because there are no effective diagnostic tools to verify the hemangioma, more effort should be put into preoperative imaging tests to avoid misdiagnosis and poor decisions).

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

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

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

BACKGROUND:

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

OBJECTIVE:

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

METHODS:

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

RESULTS:

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

CONCLUSION:

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

How reliable and accurate is indocyanine green video angiography in the evaluation of aneurysm obliteration?

INTRODUCTION

Indocyanine green video angiography (ICG-VA) has been recently introduced into neurovascular surgery and gained a role in assessing vessel patency and obliteration of intracranial aneurysms (IA) after clipping. Although its correlation with intra-postoperative angiography was demonstrated in previous studies, difficulties in evaluating aneurysm obliteration have not been reported. We report reliability and accuracy of ICG-VA in 109 clipped aneurysms with attention given to five cases in which ICG-VA evaluation resulted in false indication that aneurysms were secure in terms of complete obliteration.

MATERIALS AND METHODS

A retrospective chart review was performed of IAs surgically treated by a single surgeon from January 2009. In all cases, aneurysm obliteration was confirmed by a combination of microdoppler ultrasonography (MUSG), ICG-VA, and post-operative angiography.

RESULTS

ICG-VA appropriately assessed vessel patency and aneurysm obliteration in 93.5% of aneurysms clipped. In four cases (3.6%), puncturing the dome of the aneurysm after satisfactory clipping revealed persistent flow within the aneurysm despite ICG-VA showing no flow after clipping. In one case (0.9%), ICG-VA showed persistent flow within the aneurysm and MUSG did not, and puncture of the dome confirmed no flow within the aneurysm. In one case (0.9%), ICG-VA failed to demonstrate residual neck.

CONCLUSION

ICG-VA is a simple and safe procedure and an important adjunct to microsurgical clipping of aneurysm. Although ICG-VA assesses vessel patency and obliteration of aneurysms in most cases, applying the principles of microsurgery in aneurysm clipping remains a main tool for obtaining the complete obliteration of aneurysm along with preservation of the normal vasculature.

Endoscope-integrated ICG technology: first application during intracranial aneurysm surgery

Microscopic indocyanine green videoangiography (mICG-VA) has gained wide acceptance during intracranial aneurysm surgery by lowering rates of incomplete clipping and occlusion of surrounding vessels. However, mICG-VA images are limited to the microscopic view and some deeper areas, including the aneurysm sac/neck posterior side, cannot be efficiently assessed as they are hidden by the aneurysm, clips, or surrounding structures. Contrarily, endoscopes allow a wider area of visualization, but neurosurgical endoscopes to date only provided visual data. We describe the first application of endoscope ICG-integrated technology (eICG) applied in an initial case of anterior communicating artery aneurysm clipping. This new technique provided also relevant information regarding aneurysm occlusion and patency of parent and branching vessels and small perforating arteries. eICG-VA provided additional information compared to mICG-VA by magnifying areas of interest and improving the ability to view less accessible regions, especially posterior to the aneurysm clip. Obtaining eICG sequences required currently the microscope to be moved away from the operating field. eICG-VA was only recorded under infrared illumination which prevented tissue handling, but white-infrared light views could be interchanged instantaneously. Further development of angled endoscopes integrating the ICG technology and dedicated filters blocking the microscopic light could improve visualization capacities even further. In conclusion, as a result of its ability to reveal structures around corners, the eICG-VA technology could be beneficial when used in combination with mICG-VA to visualize and confirm vessel patency in areas that were previously hidden from the microscope.

Endoscopic indocyanine green video angiography in aneurysm surgery: an innovative method for intraoperative assessment of blood flow in vasculature hidden from microscopic view

Recently, intraoperative fluorescence video angiography using indocyanine green (ICG) has been widely used in aneurysm surgery. This is a simple and useful method to confirm complete occlusion of the aneurysm lumen and preservation of blood flow in the arteries around the aneurysm. However, the observation field of ICG video angiography is limited under a microscope, making it difficult to confirm the flow in the arteries behind the parent arteries or aneurysm. The authors developed a new technique of intraoperative endoscopic ICG video angiography to assess the blood flow in perforating arteries hidden by the parent arteries or aneurysm. The endoscope emits excitation light with a wavelength of approximately 800 nm, and video images were obtained through a cut filter. The authors used this ICG fluorescence endoscope in treating 3 patients with unruptured cerebral aneurysms. During clip placement, the endoscope was inserted to confirm aneurysm occlusion. Then, ICG was intravenously administered, and the fluorescence in the vessels was observed via the endoscope as well as under the microscope. The blood flow in the perforating arteries was clearly identified, and no procedural complication occurred. The authors conclude that the technique is very useful and facilitates intraoperative real-time assessment of the patency of perforating arteries behind parent arteries or aneurysms.

The use of intraoperative near-infrared indocyanine green videoangiography in the microscopic resection of hemangioblastomas

BACKGROUND

The authors assessed the usefulness of intraoperative near-infrared indocyanine green videoangiography (ICG-VA) in the microscopic resection of hemangioblastomas.

METHODS

From January 2009 to February 2012, nine consecutive patients (seven men, two women) who underwent surgery for hemangioblastomas using intraoperative ICG-VA were included in this study. Surgery was performed on four cystic cerebellar lesions with mural nodules, two solid tumors (one in the cerebellar hemisphere and one in the medulla oblongata), one spinal tumor and multiple tumors in two patients with von Hippel-Lindau disease. Of the nine patients, three were treated for recurrent tumor. The ICG-induced fluorescence images of hemangioblastomas with variable presentation were evaluated.

RESULTS

All tumors could be completely removed en bloc. Blood flow in the tumor and tumor-related vessels at the brain surface were clearly detected by ICG-VA in all cases, except one recurrent tumor where postoperative adhesive scar tissue obstructed ICG-induced fluorescence resulting in poor delineation of the blood flow patterns and tumor margins. ICG-VA was also helpful for detecting the multiple small mural nodules within the cyst or the tumors buried under thin gliotic neural tissue despite reduced fluorescence.

CONCLUSION

Intraoperative ICG-VA is a safe and easy modality for confirming the vascular flow patterns in hemangioblastomas. In addition, ICG-VA provided useful information for intracystic small lesions or lesions concealed under thin brain tissue in order to accomplish total resection of these tumors.

Multistage indocyanine green videoangiography for the convexity dural arteriovenous fistula with angiographically occult pial fistula

Recently, intraoperative indocyanine green (ICG) videoangiography has become a common technique for treating cerebrovascular diseases. We report a case of dural arteriovenous fistula (AVF) treated with direct surgery using intraoperative ICG videoangiography. A 41-year-old man with right hemiplegia caused by a left subcortical hemorrhage was transferred to our hospital. Digital subtraction angiography (DSA) revealed a left convexity parasagittal dural AVF. Surgical resection of the dural AVF was performed using step-by-step ICG videoangiography 4 times in each dissection procedure, which precisely delineated the structure of the dural AVF. After a circular incision of the dura around the fistular point, repeated ICG videoangiography identified the residual fistula between the pial artery from the middle cerebral artery and the draining vein. Complete disappearance of the AVF was confirmed by ICG videoangiography after this pial fistula was removed. Postoperative DSA revealed no residual AVF. Accurate detection of all fistular points and complete resection, including the dura mater and pial vessels, are necessary to avoid rebleeding caused by the residual dural AVF due to incomplete obliteration of the fistular points. Intraoperative ICG videoangiography could provide information on angiographically occult vascular malformation, such as pial fistulas, that cannot be detected by preoperative DSA. Our findings suggest that multistage intraoperative ICG videoangiography can be quite useful for complete resection of a dural AVF with angiographically occult pial fistula.

Clinical application of fluorescence imaging of liver cancer using indocyanine green

Recently, fluorescence imaging using indocyanine green (ICG) has been applied to hepatobiliary surgery, not only to visualize the bile ducts, but also to identify liver cancer during surgery. In this technique, ICG is administered intravenously at a dose of 0.5 mg/kg body weight for routine liver function testing before surgery. Intraoperatively, liver cancer can be readily identified by fluorescence imaging on the liver surface before resection and on the cut surface of the resected specimen. This is achieved by visualizing fluorescence from the area of impaired bile excretion in hepatocellular cancer tissue and in the liver parenchyma surrounding metastatic liver cancers. Liver cancer navigation surgery, first developed in Japan, is also possible, and it represents one of the few fluorescence imaging techniques for cancer that have reached the stage of clinical application; with further developments in basic research, fluorescence imaging is expected to become an indispensable technique for the diagnosis and treatment of liver cancer.

Minimally invasive tubular retractor system for adequate exposure during surgical obliteration of spinal dural arteriovenous fistulas with the aid of indocyanine green intraoperative angiography

Effective surgical obliteration of spinal dural arteriovenous fistulas (DAVFs) traditionally requires laminectomy or hemilaminectomy to allow intradural exposure and occlusion of the draining vein. The authors present successful treatment of a spinal DAVF by using a tubular retractor system to provide minimally invasive exposure at the L5-S1 level adequate for both microsurgical treatment and intraoperative indocyanine green angiography.

A review of indocyanine green fluorescent imaging in surgery

The purpose of this paper is to give an overview of the recent surgical intraoperational applications of indocyanine green fluorescence imaging methods, the basics of the technology, and instrumentation used. Well over 200 papers describing this technique in clinical setting are reviewed. In addition to the surgical applications, other recent medical applications of ICG are briefly examined.

Surgical strategies for aneurysms deemed unclippable and uncoilable

Although most cerebral aneurysms can nowadays be successfully treated either by standard clipping or sole coiling, a subset of aneurysms may not be amenable to standard clipping or coiling and require alternative treatment options. Surgical options, other than clipping and/or endovascular options other than sole coiling, may be the optimal treatment plan for some complex aneurysms. Surgical strategies for such complex aneurysms include parent artery occlusion, revascularization procedures and flow redirection. In this article, we review which factors are predictive of failure of conventional aneurysm treatment options; summarize key information needed to orient treatment decision; and discuss surgical options for unclippable and uncoilable aneurysms.

Efficacy of indocyanine green videography and real-time evaluation by FLOW 800 in the resection of a spinal cord hemangioblastoma in a child: case report

A 19-month-old child was gradually suffering from gait disturbance and was referred by his pediatrician to the authors' institution. Spinal MRI showed Gd-enhanced spinal cord tumor and congestive myelopathy. Intraoperatively the lesion was seen to be a hemangioblastoma. Because discrimination of the arterialized draining veins from the feeding arteries was difficult, indocyanine green videography was conducted to differentiate them. Real-time evaluation by FLOW 800 revealed that the slope of the average signal intensity in the feeding artery was steeper than that of the arterialized veins. The tumor was successfully resected, and postoperative indocyanine green videography showed total removal of the tumor as a signal-negative region; the circulation time between the feeding artery and the main draining vein was prolonged from 2.5 to 5.5 seconds. Indocyanine green videography and real-time evaluation by FLOW 800 were objective and effective for the excision of a tumor retaining the arteriovenous shunt. The patient recovered from congestive myelopathy and gait disturbance.

The role of intraoperative micro-Doppler ultrasound in verifying proper clip placement in intracranial aneurysm surgery

INTRODUCTION

Aneurysmal subarachnoid hemorrhage constitutes a clinical entity associated with high mortality and morbidity. It is widely accepted that improper clip placement may have as a result of incomplete aneurysm occlusion and/or partial or complete obstruction of an adjacent vessel. Various modalities, including intraoperative or postoperative digital subtracting angiography, near-infrared indocyanine green angiography, micro-Doppler ultrasonography (MDU), and neurophysiological studies, have been utilized for verifying proper clip placement. The aim of our study was to review the role of MDU during aneurysmal surgery.

METHODS

A literature search was performed using any possible combination of the following terms: "aneurysm," "brain," "cerebral," "clip," "clipping," "clip malpositioning," "clip repositioning," "clip suboptimal positioning," "Doppler," "intracranial," "microsurgery," "micro-Doppler," "residual neck," "ultrasonography," "ultrasound," and "vessel occlusion". Additionally, reference lists from the retrieved articles were reviewed for identifying any additional articles. Case reports and miniseries were excluded.

RESULTS

A total of 19 series employing intraoperative MDU during aneurysmal microsurgery were retrieved. All studies demonstrated that MDU accuracy is extremely high. The highest reported false-positive rate of MDU was 2 %, while the false-negative rate was reported as high as 1.6 %. It has been demonstrated that the presence of subarachnoid hemorrhage, specific anatomic locations, and large size may predispose to improper clip placement. Intraoperative MDU's technical limitations and weaknesses are adequately identified, in order to minimize the possibility of any misinterpretations.

CONCLUSION

Intraoperative MDU constitutes a safe, accurate, and low cost imaging modality for evaluating blood flow and for verifying proper clip placement during microsurgical clipping.

Selective intraarterial injection of ICG for fluorescence angiography as a guide to extirpate perimedullary arteriovenous fistulas

BACKGROUND

Fluorescence angiography with indocyanine green (ICG) provides real-time information regarding the patency of vessels. To enhance the capability to delineate flow direction, flow velocity and sequence of dye filling in different components of complex spinal vascular lesions such as perimedullary arteriovenous fistulas (AVFs), we tried selective intraarterial injection of ICG with catheterization in the proximity of the AVFs.

METHOD

Prior to taking the position for surgery, a metallic introducer sheath was placed into the femoral artery, and placed over the patient's lateral buttock. After the exposure of the AVFs, a standard angiographic catheter was advanced into the proximal portion of the feeding artery and a small volume of diluted ICG (0.06 mg in 5 ml saline for one examination) injected repeatedly. To avoid the thromboembolism, heparinized saline was perfused continuously thorough the catheter and sheath.

FINDINGS

The small injection volume and the close proximity of the injection site to the lesions resulted in quick rise and fall of the fluorescence without any background. Time and spatial resolution of analysis were enhanced; flow dynamics such as direction, velocity and alteration after temporary occlusion were well visualized. The feeders and drainers were clearly distinguished, and the shunts could be precisely identified.

CONCLUSIONS

Selective intraarterial injection ICG fluorescence angiography was very useful for perimedullary AVFs. Albeit that it requires intraoperative selective catheterization, this repeatable technique has an advantage to improve temporary resolution and provides accurate information of the flow dynamics through the complex anatomy of vascular lesions.

Intraoperative Matas test using microscope-integrated intraoperative indocyanine green videoangiography with temporary unilateral occlusion of the A1 segment of the anterior cerebral artery

OBJECTIVE

The aim of the present study was to assess a new technique of surgical microscope-based indocyanine green (ICG) videoangiography (VAG) to confirm the patency of the anterior communicating artery (AcomA) after clipping AcomA aneurysms.

METHODS

Aneurysmal clipping of five cases of unruptured, broad-neck AcomA aneurysm was performed using the Carl Zeiss Surgical Microscope OPMI Pentero INFRARED 800.

RESULTS

In all five patients, after clipping AcomA aneurysms, the patency of AcomA was confirmed using ICGVAG findings and temporary unilateral occlusion of the A1 segment of the anterior cerebral artery using temporary clips. Images were excellent and enabled a real-time surgical assessment because the structures of interest, including vessels, perforating arteries, or residual aneurysm neck, were visible to the surgeon's eye under the microscope in all five patients.

CONCLUSIONS

ICGVAG and temporary unilateral occlusion with clips provides a simple, reliable, real-time, and rapid intraoperative assessment of the patency of AcomA. This technique may help to improve the quality of neurosurgical procedures.

Surgical treatment of unruptured intracranial aneurysms in a low-volume hospital--outcome and review of literature

BACKGROUND

The aim of this study was to evaluate surgical outcome of unruptured intracranial aneurysms (UIAs) in a low-volume hospital and compare the results with the recent literature.

METHODS

A retrospective review of all consecutive craniotomies for UIA from July 1999 through June 2009 was performed. Morbidity was defined as modified Rankin Scale (mRS) ≥ 3 and evaluated six weeks after surgery. Cognitive function was evaluated at rehabilitation-to-home discharge. A PubMed database search (2001-2011) seeking retrospective, single-center studies reporting on surgical outcome of UIAs was performed.

RESULTS

There were 47 procedures performed in 42 patients to treat 50 UIAs (mean of 5 annual craniotomies). The mean age was 54.7 ± 12.1 years and mean aneurysm size was 7.6 ± 4.0mm. Favorable outcome (mRS 0-2) at six weeks after surgery was achieved in 45 of 47 procedures (95.7%). Aneurysm size ≥ 12 mm was statistically significant related to adverse outcome defined as mRS change ≥ 1 (71% vs. 29%; p = 0.018). Five patients (10.6%) with favorable neurological outcome (mRS 2) presented with cognitive impairment at rehabilitation-to-home discharge. There was no significant difference in overall morbidity and mortality comparing low- and high-volume hospitals (4.0% vs. 4.8%; p = 0.85).

CONCLUSIONS

Low-volume hospitals may achieve good results for surgical treatment of UIAs. The results indicate that defining numeric operative volume thresholds is not feasible to guide centralization of aneurysm treatment.

Malignancies of the spinal cord

The management of intramedullary spinal cord tumors (IMSCT) is primarily concerned with the preservation of existing neurologic function. To this end, clinical scientists are continually seeking tools and techniques to improve the safety and efficacy of tumor resection and control. Further advances in safety and efficacy can be proposed at each phase of management, from pre-operative screening to post-treatment monitoring. Innovations within the areas of molecular biology and genetics, intraoperative imaging and stereotactic radiosurgery offer exciting new options to explore in the management of IMSCT. This section will review the pathophysiology and epidemiology of IMSCT and the state-of-the-art management before delving into the promising new tools and techniques for each phase of management.

Long-term visual outcome and aneurysm obliteration rate for very large and giant ophthalmic segment aneurysms: assessment of surgical treatment

BACKGROUND

Standard endovascular therapy has shown little success in treatment of very large and giant ophthalmic segment aneurysms. We hypothesize that surgical treatment of these aneurysms yields better results in terms of visual function and aneurysm obliteration.

METHODS

The Toronto Brain Vascular Malformation Study Group database was analyzed to retrieve patients treated surgically for very large (>15 mm) and giant aneurysms of the ophthalmic segment of the carotid artery. Preoperative data and postoperative long-term outcomes with specific consideration for visual function and aneurysm obliteration were evaluated.

RESULTS

Of the 257 patients with ophthalmic and paraophthalmic aneurysms, 38 patients had very large or giant aneurysms. Twenty-one underwent surgical treatment; 19 had direct clipping; 1 had trapping, and 1 underwent trapping and bypass. Fifteen patients had unruptured and six had ruptured aneurysms. The mean follow-up period was 88 months. Six (28%) aneurysms had a small residual neck remnant. Of the 12 patients with documented preoperative visual deficit, 9 (75%) improved, 2 (16%) remained stable, and 1 (8%) worsened. Two patients had mild to moderate new visual deficit. Thus, the surgery-related visual complications were 14%. Eighteen patients (86%) had a good or excellent outcome (GOS IV and V). Presentation with prior visual deficit and poor neurological function were predictors of worse visual and clinical outcome, respectively (P = 0.02 and 0.01).

CONCLUSIONS

There is considerable surgery-related risk for optic pathways during treatment of very large and giant ophthalmic segment aneurysms. Surgery, however, seems to be the treatment of choice in terms of overall visual outcome and aneurysm obliteration as compared to the current endovascular results in this subset of patients.

Multiple intraoperative monitoring-assisted microneurosurgical treatment for anterior circulation cerebral aneurysm

This study investigated the efficacy of multiple intraoperative monitoring techniques including indocyanine green angiography (ICGA), somatosensory evoked potential (SSEP) and motor evoked potential (MEP) in the clinical outcome of microneurosurgical treatment for anterior circulation cerebral aneurysm. Fifty-two anterior circulation cerebral aneurysms (Hunt and Hess [H&H] grades 0, 1 or 2) from 45 Chinese in-patients were completely clipped. In one patient, ICGA directed neurosurgeons to readjust aneurysmal clips in order to eliminate a residual aneurysm and restore patency of a branching artery. SSEP/MEP directed neurosurgeons to implement intervention measures in 12 patients for recovery of SSEP/MEP changes, and SSEP/MEP changes partially/totally recovered in 11 of these 12 patients (91.6%). Postoperative motor deficits were observed in three patients, two of which were Glasgow Outcome Scale level 3 (4.4%). In conclusion, for patients with anterior circulation cerebral aneurysm (H&H grade < 3), multiple intraoperative monitoring was beneficial for finding residual aneurysms, detecting ischaemic events in the perforating arteries and reducing severe postoperative motor deficiency.

Monitoring techniques for prevention of procedure-related ischemic damage in aneurysm surgery

OBJECTIVE

To describe the application of intraoperative monitoring techniques during aneurysm surgery and to discuss the advantages and limitations of these techniques in prevention of postoperative neurologic deficits.

METHODS

Articles found in the literature through PubMed for the time frame 1980-2011 and the authors' personal files were reviewed.

RESULTS

Various techniques for detection of vascular insufficiency are available, including direct methods to measure cerebral blood flow and indirect methods to evaluate the integrity of neurologic pathways.

CONCLUSIONS

The choice of monitoring modality should be governed by the vessel and by the vascular territory most at risk during the planned procedure with proper awareness of the potential limits related to each technique. Aneurysm surgery monitoring should help to address issues of continuity and provide a morphologic and functional assessment. Although the use of monitoring devices is still not routine in aneurysm surgery and no standards have been established, combining different monitoring techniques is crucial to optimize aneurysm surgery and avoid or minimize complications.

Intraoperative indocyanine green video-angiography: spinal dural arteriovenous fistula

STUDY DESIGN

Technical note.

OBJECTIVE

To describe the use of intraoperative indocyanine green (ICG) video-angiography for obliteration of a spinal dural arteriovenous fistula (DAVF) and to show a video clip.

SUMMARY OF BACKGROUND DATA

ICG video-angiography is an emerging tool for delineating intraoperative vascular anatomy, and it has a significant potential in the treatment of vascular diseases in the spine.

METHODS

The authors presented a case of a 73-year-old man with progressive and debilitating bilateral lower extremity weakness. The patient was diagnosed with a spinal DAVF of 10th thoracic spine based on the results of conventional spinal angiography.

RESULTS

The patient underwent T9-10 laminotomy for microsurgical clip occlusion. Intraoperative ICG video-angiography was used before clip placement to identify the arterialized veins of the fistula and after clip placement to confirm obliteration of the fistulous connection and restoration of normal blood flow.

CONCLUSION

Intraoperative ICG video-angiography serves an important role in the microsurgical treatment of DAVF. It is simple and provides real-time information about the precise location of spinal DAVF and result after obliteration of spinal DAVF.

Enhanced analysis of intracerebral arterioveneous malformations by the intraoperative use of analytical indocyanine green videoangiography: technical note

In cerebral arterioveneous malformations (AVMs) detailed intraoperative identification of feeding arteries, nidal vessels and draining veins is crucial for surgery. Intraoperative imaging techniques like indocyanine green videoangiography (ICG-VAG) provide information about vessel architecture and patency, but do not allow time-dependent analysis of intravascular blood flow. Here we report on our first experiences with analytical indocyanine green videoangiography (aICG-VAG) using FLOW 800 software as a useful tool for assessing the time-dependent intraoperative blood flow during surgical removal of cerebral AVMs. Microsope-integrated colour-encoded aICG-VAG was used for the surgical treatment of a 38-year-old woman diagnosed with an incidental AVM, Spetzler Martin grade I, of the left frontal lobe and of a 26-year-old man suffering from seizures caused by a symptomatic AVM, Spetzler Martin grade III, of the right temporal lobe. Analytical ICG-VAG visualization was intraoperatively correlated with in situ micro-Doppler investigation, as well as preoperative and postoperative digital subtraction angiography (DSA). Analytical ICG-VAG is fast, easy to handle and integrates intuitively into surgical procedures. It allows colour-encoded visualization of blood flow distribution with high temporal and spatial resolution. Superficial major and minor feeding arteries can be clearly separated from the nidus and draining veins. Effects of stepwise vessel obliteration on velocity and direction of AVM blood flow can be objectified. High quality of visualization, however, is limited to the site of surgery. Colour-encoded aICG-VAG with FLOW 800 enables intraoperative real-time analysis of arterial and venous vessel architecture and might, therefore, increase efficacy and safety of neurovascular surgery in a selected subset of superficial AVMs.

FLOW 800-assisted surgery for arteriovenous malformation

FLOW 800 is software for analytical colour visualisation and objective evaluation of fluorescence video obtained by microscope-integrated intraoperative indocyanine green fluorescence angiography. A 56-year-old male underwent surgical excision of a large complex arteriovenous malformation (AVM) of the right parietal region. FLOW 800 software was used to identify feeding arteries, arterialised veins and passing vessels. Complete excision of the AVM was achieved, confirmed by FLOW 800 and postoperative digital subtraction angiography. The role of FLOW 800, its applications and limitations in AVM surgery are discussed.