脳動脈瘤手術の工夫(<特集>脳動脈瘤手術update)  [in Japanese] Techniques for Aneurysm Surgery(<Topic>Surgical Approach for Cerebral Aneurysm)  [in Japanese]

In surgical procedures to dissect the sylvian fissure, the fissure is commonly unfolded by the attachment of all sylvian veins to the temporal lobe. During this procedure, cerebral edema and contusion in the frontal lobe are often caused by sacrificing bridging veins from the frontal lobe and excessive retraction on the frontal lobe. In this procedure, some sylvian veins must be kept on the side of the frontal lobe to preserve the bridging vein. In many cases, detachment of the sylvian vein from the surface of the temporal lobe is required. The sylvian vein can be detached from the temporal lobe using the space around the temporal artery right under the sylvian vein. For detachment of adhesions between the frontal and temporal lobes, a "paper knife technique" is available in which a surgical site is generated by cutting upwards from the subarachnoid space around M1. In a "denude technique," a wide surgical field can be obtained with less retraction of the frontal lobe by detaching the arachnoid membrane from the sylvian vein and thus allowing venous extension. During dissection of the sylvian fissure, arteries and veins belonging to the temporal lobe spread while adhering to the frontal lobe. In this case, the site to dissect is the frontal-lobe side where the vessels are located, even if the sylvian fissure is widely unfolded. Conversely, when cerebral vessels belonging to the frontal lobe are attached to the temporal lobe, the site to dissect is on the temporal lobe side, where the vessels are located. Thus the concept of a "microvascular sylvian fissure" in which detailed vessel structures are captured at a microscopic level is important in terms of preventing damage to blood vessels, pia matter and brain tissue. It is crucial to obtain a large surgical field and confirm where blood vessels belong. To detach an aneurysm attached to arteries such as M2, A2 or perforating arteries and deep veins, without causing damage, using the tip of micro-forceps for microvascular anastomosis as a raspatory is useful. Other detailed technical ideas are introduced. These include: pulling the aneurysm into the surgical site by transposing the artery and aneurysm using brain spatulas, silk threads, and Aron alpha to confirm adjacent vascular structures such as perforating arteries; using a "double-clip technique" to confirm complete clipping with 2 clips; and deliberately shifting the bayonet clip to preserve perforating arteries.