Progress in the treatment of unruptured aneurysms.

Recent technological progress has reduced the complication rate of unruptured aneurysm. We treated 128 unruptured aneurysms between April 2006 and March 2012. Seventy-six aneurysms (59 %) were clipped and 52 (41 %) were coil embolized. After 2010, we applied new instruments, i.e., near-infrared indocyanine-green videoangiography (ICG), an intraoperative endoscope, preoperative detailed MRI, and a stent-assisted coil embolization. In the results: (1) In 60 aneurysms treated before 2009, three patients showed a deterioration of more than two points in mRS (5 %). In 68 aneurysms treated after 2010, no patients showed deterioration (0 %) (p: n.s.). (2) No patients died and 126 patients (98 %) were discharged to home directly. (3) No patients showed rupture after treatment. In conclusion, the appropriate selection of treatment and recent technological progress have facilitated sophisticated treatment of unruptured aneurysms. Recently, the complication rate in surgery and endovascular surgery for unruptured aneurysms has become acceptably low.

Relationship between preoperative magnetic resonance imaging and surgical findings: aneurysm wall thickness on high-resolution T1-weighted imaging and contact with surrounding tissue on steady-state free precession imaging.

This study evaluated the aneurysm wall thickness by high-resolution T1-weighted imaging and the contact between the aneurysm and surrounding tissue by steady-state free precession (SSFP) imaging. The surgical findings were prospectively compared with these preoperative magnetic resonance (MR) imaging findings in 35 consecutive patients with 37 unruptured cerebral aneurysms (UCAs). The aneurysm wall was not visible in 13 UCAs, but was visible in 23. Subarachnoid space between the aneurysm and surrounding tissue was visible in 16 UCAs, a visible layer of cerebrospinal fluid (CSF) between the aneurysm and surrounding tissue in 12, and no visible layer in 7. MR imaging predicted the surgical findings in 29 UCAs (78%), showed different findings in six UCAs (16%), and two (5%) could not be evaluated due to insufficient quality of preoperative MR images. Among the UCAs with different findings, five UCAs had a partially thin wall even though high-resolution T1-weighted imaging had shown a visible wall, and one UCA showed less contact with the surrounding tissue even though the SSFP imaging had shown no visible CSF layer. In conclusion, high-resolution T1-weighted imaging and SSFP imaging provided significant additional preoperative information regarding UCAs and the surrounding tissue.

Treatment selection for ruptured aneurysm and outcomes: clipping or coil embolization.

The International Subarachnoid Aneurysm Trial has shown that coil embolization achieves a better outcome for aneurysms treatable by either clipping or coil embolization. However, many ruptured aneurysms are hardly treatable by either clipping or coil embolization. Selection of either clipping or coil embolization will affect the treatment outcome for ruptured aneurysms. The relationship between patient selection and treatment outcome in a so-called "regional center hospital" in Japan must be clarified. This study included 113 patients with ruptured intracranial saccular aneurysms measuring less than 10 mm. Selection criteria for coil embolization were principally paraclinoid or posterior circulation aneurysm, Hunt and Hess grade IV or over, and patient age 75 years or older. Other aneurysms were principally treated by clipping. Aneurysms with a dome/neck ratio of less than 1.5, distorted aneurysms, Hunt and Hess grades I-III, patient age 74 years or younger, and middle cerebral artery aneurysm were actively treated by clipping. A few exceptional indications were considered in detail. Low invasiveness coil embolization is better than clipping to obtain good neurological outcome for patients with perforators difficult to dissect, aneurysms difficult to dissect due to previous open surgery, and aneurysms requiring bilateral open surgery, despite the slightly higher rebleeding rate in coil embolization. Overall outcomes were modified Rankin Scale (mRS) 0-2 in 82 of 113 patients (73%) and mRS 3-6 in 31 (27%). Appropriate selection of clipping or coil embolization can achieve acceptable treatment outcomes for ruptured aneurysm.