Korean Journal of Cerebrovascular Surgery 2002;4(1):5-8.
Published online March 1, 2002.
What is a True Less Invasiveness for a Patient?.
EGUCHI, Tsuneyoshi
Department of Neurosurgery, Kameda General Hospital, Kamogawa, Chiba, Japan.
These days, a less invasive surgery is stressed. One current thought is that the endovascular surgery itself is the less invasive and safer surgery for a cerebral aneurysm, and not the microsurgery. Is this true? We have evaluated the merits and demerits of each method. Our conclusion is as follows. Endovascular Surgery should be considered as an alternative, only for the specific patients. Microsurgery itself retains its position of the first treatment of choice for a cerebral aneurysm. "Less invasive" cannot be equated with "less dangerous". We will show the above reasons using slides and videotapes of several patients.
Key Words: Cerebral aneurysm, Microsurgery, Endovascular surgery, Less invasiveness, Mild mypothermia, Vasospasm


The target of ruptured aneurysm treatment is to prevent re-rupture safely and completely, and to reduce the occurrence rate of vasospasm caused by subarachnoid hemorrhage (SAH).
   Currently, there are two modalities of treatment, endovascular surgery and microsurgery. Which is truly "less invasive" and more beneficial for a patient?


   Each representative case will be presented. To solve the demerits at Microsurgery, various means have been tried.

Results & Discussion

In endovascular surgery, there are such merits as 1) no general anesthesia, 2) no craniotomy, 3) no brain retraction, 4) no vein sacrifice, etc. But there are definite essential demerits(Table 1). 
   Fig. 1 shows the moment of rupture during endovascular surgery. Although emergent microsurgery fortunately saved the patient, this risk of rupture during the procedure is inevitable and is an essential drawback.6) Adding to this point, it was surprisingly found during this microsurgery that the wall of the parent artery had been injured at the near end of the aneurysmal neck probably by a guide-wire or a catheter, the phenomenon of which had not been observable during the endovascular surgery(Fig. 2).
   As one of the merits of microsurgery, it has a definite effect to release the mass impact of Giant Aneurysm, even though endovascular surgery has only a questionable effect against it(Fig. 3).
   During microsurgery, we can remove the subarachnoid clot as much as possible, which is a causative substance of vasospasm.2) After microsurgery, a cisternal irrigation by Lactec solution containing urokinase4) is performed to disso-lve the subarachnoid clot more through two cisternal drains that were placed intraoperatively, with an aid of "Neuroshaker"(Fig. 4). With this procedure, we could decrease the occurrence rate of vasospasm and could raise the percentage of "Symptom-Free" from vasospasm, from 41% up to 73%.
   On the other hand, however, there are, of course, demerits of microsurgery shown in Table 2. But almost all these demerits can be reduced and overcome through general anesthesia with mild hypothermia of 32-33
(Figs. 5 and 6)1)5)7) and the following surgical tactics. 
   The mild hypothermia is not only benefit in a case of a cerebral ischemia due to a long temporary clamp of a cerebral vessel, but also can protect the brain, especially of aged patients, while the brain is retracted during microsurgery. 
   With the help of this intraoperative mild hypothermia, we can also perform the direct clipping safely even for a patient with a severe vasospasm(Figs. 7 and 8).
   We developed a "Modified Pterional Approach"(Figs. 9 and 10) or the method to cut the superior sagittal sinus at the anterior part during the Interhemispheric Approach to get an enough operative field without sacrificing the cortical or bridging veins into the venous sinuses(Fig. 11).
   With these surgical tactics, we can protect the brain from the complications of venous infarction or bleeding. Thus, the demerits of microsurgery can be overcome.


   Endovascular surgery should be considered as an alternative only for specific patients such as those who can't tolerate the general anesthesia or whose aneurysms are located in a difficult site when surgically approached.3) It must be stressed that "Less Invasive" cannot be equated with "Less Dangerous".8)


  1. Eguchi T, Iai S, Ogai M, et al. Mild Hypothermia in aneurysm surgery. Proceedings of 11th International Congress of Neurological Surgery, Bologna, Monduzzi Editore, 1997, pp 979-88

  2. Gruber A, Ungersbock K, Reinprecht A, et al. Evaluation of cerebral vasospasm after early surgical and endovascular treatment of ruptured intracranial aneurysms. Neurosurgery 42:258-67, 1998

  3. Gruber A, Killer M, Bavinzski G, et al. Clinical and angiographic results of endosacccular coiling treatment of giant and very large intracranial aneurysms: A 7-year, single-center experience. Neurosurgery 45:793-803, 1999

  4. Kodama N, Sasaki T, Kawakami M, et al. Cisternal irrigation therapy with Urokinase and Ascorbic Acid for prevention of vasospasm after aneurysmal subarachnoid hemorrhage outcome in 217 patients. Surg Neurol 53:110-8, 2000

  5. Maher J, Hachinski V. Hypothermia as a Potential Treatment for Cerebral Ischemia. Cerebrovasc Brain Metab Rev 5:277-300, 1993

  6. McDougall CG, Halbach VV, Dowd CF, et al. Causes and management of aneurysmal hemorrhage occurring during embolization with Guglielmi detachable coils. J Neurosurg 89:87-92, 1998

  7. Ogawa A, Sato H, Sakurai Y, et al. Limitation of Temporary Vascular Occlusion During Aneurysm Surgery. Surg Neurol 36:453-57,1991

  8. Thomas JE, Armonda RA, Rosenwasser RH. Endosaccular thrombosis of cerebral aneurysms: strategy, indications, and technique. Neurosurg Clin N Am 11:101-21, 2000

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