Cent Eur Neurosurg 2005; 66(1): 7-8
DOI: 10.1055/s-2004-836229

© Georg Thieme Verlag Stuttgart · New York

Commentary on the Article of A. Raabe, J. Beck, V. Seifert: Technique and Image Quality of Intraoperative Indocyanine Green Angiography During Aneurysm Surgery Using Surgical Microscope Integrated Near-Infrared Video Technology

Kommentar zur Arbeit von A. Raabe, J. Beck, V. Seifert: Technik und Bildqualität der operationsmikroskop-integrierten Indozyaningrün-VideoangiographieJ. Hernesniemi1 , M. Niemelä1 , R. Kivisaari1 , M. Porras1 , A. Karatas1 , K. Ishii1
  • 1Department of Neurosurgery, UH of Helsinki, Helsinki, Finland
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Publication History

Publication Date:
02 March 2005 (online)

An incompletely treated aneurysm may re-grow and lead to recurrent symptoms of hemorrhage or mass effect. The rebleeding rate of aneurysms with residual necks is between 3.5 % and 28 %; in the very long-term follow-up in extremely complex aneurysms operated on by Drake and Peerless the rebleeding rate was 10 %. Aneurysm re-growth has been reported to occur in 3.5 to 15 % of patients. The high rebleeding rate in the long term, i. e. 10-20 years, emphasizes the importance of perfect clipping (and nowadays also of complete occlusion by endovascular means). But also aneurysms with perfect clip placement may rupture or re-grow with mass effect and this was also our experience over the long term in Finland, a country with the possibility of carrying out long-term follow-ups and a country with a large number of patients with cerebral aneurysms (The Kuopio and Helsinki total experience is > 11 000 patients, close to 500 new cerebral aneurysm patients annually are seen in these two centers).

Depending on the definition and use of control angiographs, the reported incidence of residual neck after surgical clipping of an aneurysm ranges between 3.8 % and 18 %. Despite our large experience with thousands of cerebral aneurysms operated on, our overall result of 12 % of incomplete closures remains within the wide range of previous figures. This might be due to non-selection of the patients for surgery but also due to our strict criteria with respect to small neck remnants which might be considered as successful surgical results in other series. Even the slightest “dog ear” is considered by us to be a neck remnant. Such neck remnants may not be recognized on routine control angiograms, or not considered to be failures in other series. Furthermore, postoperative control angiography is not routinely performed in many institutions, and many of the surprises with partially ligated or filling aneurysms, or occluded vessels, occurring even with the most experienced neurosurgical hands, remain hidden. The few institutions which have presented excellent postoperative morphological results may not represent the average results achieved by surgery, or possibly their criteria for aneurysm remnants are different. However, in the series of Drake and Peerless (surgeons with a total experience of 5 000 aneurysm operations) of 1 767 vertebrobasilar aneurysms, total obliteration was achieved in only 82.5 %. Of course this result is also biased by the extremely difficult aneurysms with respect to site and size they treated. In our Helsinki experience the incidence of aneurysm neck remnants in posterior circulation aneurysms hidden deep in small gaps was also significantly higher than in middle cerebral artery aneurysms, the most common aneurysms in the Finnish series. Large or giant aneurysms were also more often left with neck - often intentionally - so as not to occlude any branches.

The reported high rates of unexpected major vessel occlusions, also seen in our experience, harbor a great risk for the patient - although many occur without any symptoms - and they also occur after treatment by the very best surgeons. The centers which do not perform control angiographies never see the unexpected findings. It is known that at surgery it is often difficult to predict the presence of residual aneurysm or major vessel occlusion. Use of mini-Doppler has improved the situation but many distal vessels are too far away to be examined. The good results of intraoperative DSA in the prevention of vessel occlusions and residual aneurysms have been well documented. As the vessel occlusion is diagnosed early, an immediate repositioning of the clip can hopefully prevent ischemic damage to the brain. All efforts should be concentrated during surgery on saving the vessels and replacing the clip: this is the golden moment for the patient and the surgeon.

When considering the risks of residual aneurysms and the risk of ischemic deficits caused by major vessel occlusion, basically all patients should undergo intraoperative angiography. The value of intraoperative angiography in complex (large, giant, fusiform, and VBA aneurysms) has been tested by us, and many other groups. If a simpler method is available, then intraoperative angiography should be used even in the more basic aneurysm cases. The use of intraoperative indocyanine green angiography, presented in this excellent article, is such a simple method, and for us it would appear to be one of the greatest developments in open microsurgery of cerebral aneurysms over the last few years! With the use of CT angiography and this method intra-arterial manipulation for imaging will be obsolete in open microsurgery. Once this new method of indocyanine green angiography is in more general use, it should be used in all aneurysms, and by all of those who continue to treat cerebral aneurysms using open microsurgery in order to provide the best care for our patients.

Our recent retrospective analysis revealed that ruptured, posterior circulation, and large/giant aneurysms are more prone to incomplete clipping. Therefore, these aneurysms require postoperative if not intraoperative evaluation with angiography.


  • 1 Drake C G, Peerless S J, Hernesniemi J A. Surgery of Vertebrobasilar Aneurysms. London, Ontario Experience on 1 767 patients. Springer-Verlag, Vienna 1996
  • 2 Hernesniemi J, Vapalahti M, Niskanen M, Kari A, Luukkonen M. Saccular aneurysms of the distal anterior cerebral artery and its branches.  Neurosurgery. 1992;  31 994-999
  • 3 Hernesniemi J, Vapalahti M, Niskanen M. et al . One-year outcome in early aneurysm surgery: a 14 year experience.  Acta Neurochir (Wien). 1993;  122 1-10
  • 4 International Subarachnoid Aneurysm Trial (ISAT) Collaborative Group . International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2 145 patients with ruptured intracranial aneurysms: a randomized trial.  Lancet. 2002;  360 1267-1274
  • 5 Kivisaari R P, Porras M, Öhman J, Siironen J, Ishii K, Hernesniemi J. Routine cerebral angiography after surgery for saccular aneurysms - is it worth it?.  Neurosurgery. 2004;  55 1015-1022
  • 6 Niskanen M, Hernesniemi J, Vapalahti M, Kari A. One-year outcome in early aneurysm surgery: prediction of outcome.  Acta Neurochir (Wien). 1993;  123 25-32
  • 7 Koivisto T. Prospective Outcome Study of Aneurysmal Subarachnoid Hemorrhage. Kuopio University Publications D. Medical Sciences 284 B, 2002
  • 8 The original thesis of Dr. Timo Koivisto and the reflections on the thesis by Professor M. G. Yaşargil are available at: http://www.uku.fi/tutkimus/vaitokset/2002/isbn951-781-884-X.pdf http://www.uku.fi/tutkimus/vaitokset/2002/isbn951-780-338-9.pdf

Juha HernesniemiMD, PhD, Professor and Chairman 

Department of Neurosurgery · UH of Helsinki

Topeliuksenk. 5

00260 Helsinki


Phone: +3 58/9/47 18 74 10 or +3 58/9/47 1 97 12 81

Fax: +3 58/9/47 18 75 60

Email: juha.hernesniemi@hus.fi