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Does FLOW 800 Technology Improve the Utility of Indocyanine Green Videoangiography in Cerebral Arteriovenous Malformation Surgery?
Perspectives Commentary on: Efficacy of FLOW 800 with Indocyanine Green Videoangiography for the Quantitative Assessment of Flow Dynamics in Cerebral Arteriovenous Malformation Surgery by Fukuda et al. pp. 203-210.
Does FLOW 800 Technology Improve the Utility of Indocyanine Green Videoangiography in Cerebral Arteriovenous Malformation Surgery? James Kalyvas and Robert F. Spetzler
A
t our institution, we routinely use indocyanine green (ICG) videoangiography as a surgical adjunct during resection of cerebral arteriovenous malformations (AVMs) to help identify early draining veins, en passage vessels, and feeding arteries to the nidus. Because ICG videoangiography is a safe, real-time imaging modality, our threshold to use it in these cases is low; however, its utility is also limited. ICG videoangiography provides information only about AVM vessels that can be seen directly with the microscope. As a consequence, we find ICG videoangiography most helpful for superficial or lobar AVMs and not particularly helpful for deep-seated lesions or lesions with arterial feeders arising primarily from the deep aspect of the lesion. Because of the limited microscopic view of the AVM, ICG videoangiography is an unreliable stand-alone alternative to intraoperative or postoperative digital subtraction angiography (DSA), which remains the “gold standard” for intraoperative AVM imaging. A counterexample that underscores this point is the efficacy of ICG videoangiography in aneurysm surgery—in these cases, ICG videoangiography enables the pertinent vascular anatomy to be well visualized directly, and DSA has taken on a diminished role. Conversely, in recent years, several authors have expressed greater confidence in the utility of ICG videoangiography in AVM surgery based on their experience in small case series. In their series of 9 AVMs with ICG videoangiography, Taddei et al. (4) suggested that ICG videoangiography may replace intraoperative or postoperative DSA in many cases.
We recently reported our experience with ICG videoangiography during AVM resection (5). To our knowledge, this was the largest
Key words Arteriovenous malformation - FLOW 800 - Indocyanine green videoangiography - Quantitative assessment -
Abbreviations and Acronyms AVM: Arteriovenous malformation DSA: Digital subtraction angiography ICG: Indocyanine green
WORLD NEUROSURGERY 83 [2]: 147-148, FEBRUARY 2015
consecutive case series (N ¼ 130 patients) comparing the technical and clinical outcomes of AVM surgery with ICG videoangiography (n ¼ 56 patients) and without ICG videoangiography (n ¼ 74 patients). The average AVM size was identical between groups (2.7 cm), the average Spetzler-Martin grades were similar (2.2 vs. 2.4, with ICG videoangiography vs. without ICG videoangiography), and both groups had similar rates of preoperative Gamma Knife (Elekta AB, Stockholm, Sweden) radiosurgery or endovascular embolization. Every patient underwent postoperative DSA to evaluate for residual AVM. We found no statistical advantage with ICG videoangiography in terms of reoperation for residual AVM (12.5% vs. 14.9%, with ICG videoangiography vs. without ICG videoangiography) or improvement in clinical outcome, measured by average change in modified Rankin Scale scores at 6 weeks (0.2 vs. 0.3, with ICG videoangiography vs. without ICG videoangiography). ICG videoangiography was also used significantly more often in cases of superficial or lobar AVMs and used significantly less often for infratentorial AVMs. We maintain that the limited view of the AVM provided by ICG videoangiography accounts for these findings, and we continue to use ICG videoangiography primarily as an adjunct for superficial lesions. Surgeon experience and careful evaluation of preoperative angiography remain the best guides to AVM resection, and DSA remains the best post hoc evaluation in all patients. In the present article, the authors discuss how microscopeintegrated FLOW 800 (Carl Zeiss Meditec, Inc., Dublin, California, USA) software may improve the utility of ICG videoangiography. FLOW 800 is software for analytical color visualization and
Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Robert F. Spetzler, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2015) 83, 2:147-148. http://dx.doi.org/10.1016/j.wneu.2014.09.010
www.WORLDNEUROSURGERY.org
147
PERSPECTIVES
quantification of the fluorescence video obtained during runs of ICG videoangiography. It is meant to objectify the previously subjective assessment of vascular flow dynamics captured by standard ICG videoangiography. To that end, the authors successfully demonstrate how color flow maps can quantify time intervals to reach maximal dye intensity within blood vessels and how subtle flow patterns within an AVM can be more easily recognized with FLOW 800 than with standard ICG videoangiography or with the microscope alone. They also demonstrate how AVMs can alter normal cortical perfusion in adjacent tissue and how the flow dynamics in the AVM and adjacent tissue change during the course of the AVM resection. However, they are not as successful in demonstrating how this new information affected their surgical strategy or tactics during AVM resection. The technical and clinical outcomes associated with use of FLOW 800 were beyond the scope of their study. The authors’ enthusiasm for this technology is echoed in multiple case reports by other authors. Jhawar et al. (2) and Faber et al. (1) suggest that FLOW 800 holds promise to improve the safety and efficacy of AVM surgery. Kato et al. (3) agree, with the caveat that it is most useful for superficial lesions. Herein lies the trouble with FLOW 800. Because FLOW 800 relies on what is captured by ICG videoangiography, it shares the limitations of ICG
REFERENCES 1. Faber F, Thon N, Fesl G, Rachinger W, Guckler R, Tonn JC, Schichor C: Enhanced analysis of intracerebral arterioveneous malformations by the intraoperative use of analytical indocyanine green videoangiography: technical note. Acta Neurochir (Wien) 153:2181-2187, 2011.
2. Jhawar SS, Kato Y, Oda J, Oguri D, Sano H, Hirose Y: FLOW 800-assisted surgery for arteriovenous malformation. J Clin Neurosci 18:1556-1557, 2011.
148
www.SCIENCEDIRECT.com
videoangiography. Until it is shown how FLOW 800 has altered intraoperative decision making or improved on technical or clinical outcomes, it is hard to say that it has much value over standard ICG videoangiography for AVM resection. In the end, we believe that quantifying ICG videoangiography flow may have more utility in academic studies comparing different types of AVM lesions, including lesions with different Spetzler-Martin grades or clinical presentations, or in understanding the pathophysiology of these complex lesions than it does in supporting intraoperative decision making. In conclusion, FLOW 800 does not improve the intraoperative utility of standard ICG videoangiography because it does not increase the extent of AVM visualization, and it has not been shown to provide new actionable information that is not provided already by standard ICG videoangiography. Until technology emerges to visualize the full AVM in real time, a full assessment of the AVM cannot be made, and DSA will remain necessary. In our series, no differences in reoperation rates for residual AVM or in clinical outcomes, with or without ICG videoangiography, inform this view. However, we do recommend standard ICG videoangiography for superficial AVMs as a simple, safe surgical adjunct. It can augment, but not replace, surgeon experience, careful study of preoperative angiography, and postoperative angiography.
3. Kato Y, Jhawar SS, Oda J, Watabe T, Oguri D, Sano H, Hirose Y: Preliminary evaluation of the role of surgical microscope-integrated intraoperative FLOW 800 colored indocyanine fluorescence angiography in arteriovenous malformation surgery. Neurol India 59:829-832, 2011. 4. Taddei G, Tommasi CD, Ricci A, Galzio RJ: Arteriovenous malformations and intraoperative indocyanine green videoangiography: preliminary experience. Neurol India 59:97-100, 2011. 5. Zaidi HA, Abla AA, Nakaji P, Chowdhry SA, Albuquerque FC, Spetzler RF: Indocyanine green angiography in the surgical management of
cerebral arteriovenous malformations: lessons learned in 130 consecutive cases. Neurosurgery 10(Suppl 2):246-251; discussion 251, 2014.
Citation: World Neurosurg. (2015) 83, 2:147-148. http://dx.doi.org/10.1016/j.wneu.2014.09.010 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2014.09.010
Does FLOW 800 Technology Improve the Utility of Indocyanine Green Videoangiography in Cerebral Arteriovenous Malformation Surgery? James Kalyvas and Robert F. Spetzler
A
t our institution, we routinely use indocyanine green (ICG) videoangiography as a surgical adjunct during resection of cerebral arteriovenous malformations (AVMs) to help identify early draining veins, en passage vessels, and feeding arteries to the nidus. Because ICG videoangiography is a safe, real-time imaging modality, our threshold to use it in these cases is low; however, its utility is also limited. ICG videoangiography provides information only about AVM vessels that can be seen directly with the microscope. As a consequence, we find ICG videoangiography most helpful for superficial or lobar AVMs and not particularly helpful for deep-seated lesions or lesions with arterial feeders arising primarily from the deep aspect of the lesion. Because of the limited microscopic view of the AVM, ICG videoangiography is an unreliable stand-alone alternative to intraoperative or postoperative digital subtraction angiography (DSA), which remains the “gold standard” for intraoperative AVM imaging. A counterexample that underscores this point is the efficacy of ICG videoangiography in aneurysm surgery—in these cases, ICG videoangiography enables the pertinent vascular anatomy to be well visualized directly, and DSA has taken on a diminished role. Conversely, in recent years, several authors have expressed greater confidence in the utility of ICG videoangiography in AVM surgery based on their experience in small case series. In their series of 9 AVMs with ICG videoangiography, Taddei et al. (4) suggested that ICG videoangiography may replace intraoperative or postoperative DSA in many cases.
We recently reported our experience with ICG videoangiography during AVM resection (5). To our knowledge, this was the largest
Key words Arteriovenous malformation - FLOW 800 - Indocyanine green videoangiography - Quantitative assessment -
Abbreviations and Acronyms AVM: Arteriovenous malformation DSA: Digital subtraction angiography ICG: Indocyanine green
WORLD NEUROSURGERY 83 [2]: 147-148, FEBRUARY 2015
consecutive case series (N ¼ 130 patients) comparing the technical and clinical outcomes of AVM surgery with ICG videoangiography (n ¼ 56 patients) and without ICG videoangiography (n ¼ 74 patients). The average AVM size was identical between groups (2.7 cm), the average Spetzler-Martin grades were similar (2.2 vs. 2.4, with ICG videoangiography vs. without ICG videoangiography), and both groups had similar rates of preoperative Gamma Knife (Elekta AB, Stockholm, Sweden) radiosurgery or endovascular embolization. Every patient underwent postoperative DSA to evaluate for residual AVM. We found no statistical advantage with ICG videoangiography in terms of reoperation for residual AVM (12.5% vs. 14.9%, with ICG videoangiography vs. without ICG videoangiography) or improvement in clinical outcome, measured by average change in modified Rankin Scale scores at 6 weeks (0.2 vs. 0.3, with ICG videoangiography vs. without ICG videoangiography). ICG videoangiography was also used significantly more often in cases of superficial or lobar AVMs and used significantly less often for infratentorial AVMs. We maintain that the limited view of the AVM provided by ICG videoangiography accounts for these findings, and we continue to use ICG videoangiography primarily as an adjunct for superficial lesions. Surgeon experience and careful evaluation of preoperative angiography remain the best guides to AVM resection, and DSA remains the best post hoc evaluation in all patients. In the present article, the authors discuss how microscopeintegrated FLOW 800 (Carl Zeiss Meditec, Inc., Dublin, California, USA) software may improve the utility of ICG videoangiography. FLOW 800 is software for analytical color visualization and
Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Robert F. Spetzler, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2015) 83, 2:147-148. http://dx.doi.org/10.1016/j.wneu.2014.09.010
www.WORLDNEUROSURGERY.org
147
PERSPECTIVES
quantification of the fluorescence video obtained during runs of ICG videoangiography. It is meant to objectify the previously subjective assessment of vascular flow dynamics captured by standard ICG videoangiography. To that end, the authors successfully demonstrate how color flow maps can quantify time intervals to reach maximal dye intensity within blood vessels and how subtle flow patterns within an AVM can be more easily recognized with FLOW 800 than with standard ICG videoangiography or with the microscope alone. They also demonstrate how AVMs can alter normal cortical perfusion in adjacent tissue and how the flow dynamics in the AVM and adjacent tissue change during the course of the AVM resection. However, they are not as successful in demonstrating how this new information affected their surgical strategy or tactics during AVM resection. The technical and clinical outcomes associated with use of FLOW 800 were beyond the scope of their study. The authors’ enthusiasm for this technology is echoed in multiple case reports by other authors. Jhawar et al. (2) and Faber et al. (1) suggest that FLOW 800 holds promise to improve the safety and efficacy of AVM surgery. Kato et al. (3) agree, with the caveat that it is most useful for superficial lesions. Herein lies the trouble with FLOW 800. Because FLOW 800 relies on what is captured by ICG videoangiography, it shares the limitations of ICG
REFERENCES 1. Faber F, Thon N, Fesl G, Rachinger W, Guckler R, Tonn JC, Schichor C: Enhanced analysis of intracerebral arterioveneous malformations by the intraoperative use of analytical indocyanine green videoangiography: technical note. Acta Neurochir (Wien) 153:2181-2187, 2011.
2. Jhawar SS, Kato Y, Oda J, Oguri D, Sano H, Hirose Y: FLOW 800-assisted surgery for arteriovenous malformation. J Clin Neurosci 18:1556-1557, 2011.
148
www.SCIENCEDIRECT.com
videoangiography. Until it is shown how FLOW 800 has altered intraoperative decision making or improved on technical or clinical outcomes, it is hard to say that it has much value over standard ICG videoangiography for AVM resection. In the end, we believe that quantifying ICG videoangiography flow may have more utility in academic studies comparing different types of AVM lesions, including lesions with different Spetzler-Martin grades or clinical presentations, or in understanding the pathophysiology of these complex lesions than it does in supporting intraoperative decision making. In conclusion, FLOW 800 does not improve the intraoperative utility of standard ICG videoangiography because it does not increase the extent of AVM visualization, and it has not been shown to provide new actionable information that is not provided already by standard ICG videoangiography. Until technology emerges to visualize the full AVM in real time, a full assessment of the AVM cannot be made, and DSA will remain necessary. In our series, no differences in reoperation rates for residual AVM or in clinical outcomes, with or without ICG videoangiography, inform this view. However, we do recommend standard ICG videoangiography for superficial AVMs as a simple, safe surgical adjunct. It can augment, but not replace, surgeon experience, careful study of preoperative angiography, and postoperative angiography.
3. Kato Y, Jhawar SS, Oda J, Watabe T, Oguri D, Sano H, Hirose Y: Preliminary evaluation of the role of surgical microscope-integrated intraoperative FLOW 800 colored indocyanine fluorescence angiography in arteriovenous malformation surgery. Neurol India 59:829-832, 2011. 4. Taddei G, Tommasi CD, Ricci A, Galzio RJ: Arteriovenous malformations and intraoperative indocyanine green videoangiography: preliminary experience. Neurol India 59:97-100, 2011. 5. Zaidi HA, Abla AA, Nakaji P, Chowdhry SA, Albuquerque FC, Spetzler RF: Indocyanine green angiography in the surgical management of
cerebral arteriovenous malformations: lessons learned in 130 consecutive cases. Neurosurgery 10(Suppl 2):246-251; discussion 251, 2014.
Citation: World Neurosurg. (2015) 83, 2:147-148. http://dx.doi.org/10.1016/j.wneu.2014.09.010 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2014.09.010