Complex and continuous change in hypothetic risk of rupture of intracranial cerebral aneurysms – Bleb mandala –

Background: This study of the intraoperative microscopic findings indicated complex behavior of aneurysmal bleb affects the rupture risk. Methods: A total of 300 consecutive relatively small (mean 6.2 mm) unruptured ICAs were clipped from July 2005 to January 2019. Microscopically identified blebs were divided into four types based on external appearances. Type A bleb was a thick-walled bleb. Type B bleb was a thin-walled reddish bleb. Type C bleb was a healing organized bleb. Type D was a hemosiderin-laden bleb. Type B and D blebs were considered to be risky blebs for rupture. ICAs with bleb(s) were further categorized into two types, stable aneurysms and unstable aneurysms with Type B and/or D bleb(s). The number and nature of the blebs were compared with the demographic data of the patients and radiological findings of the ICAs to evaluate possible predictors of the hypothetic rupture risk. Results: Aneurysms tended to enlarge as the number of blebs increased (p = 0.073). High risk Type B bleb had significantly larger number of blebs (p < 0.05). Healing Type C bleb was significantly more common in the group with two blebs than one bleb (p < 0.01). No significant differences were found between stable and unstable aneurysms in aneurysm multiplicity, size, and radiological bleb. Conclusions: Aneurysm state continuously changes due to the dynamic change of bleb number and nature. Our data suggests the necessity of new repeatable vessel-wall imaging technology to select risky unstable ICAs for treatment

Effectiveness of Keyhole Clipping of Unruptured Intracranial Aneurysms Detected by “Brain Dock” in Healthy Japanese Adults

In Japan, brain docking has enhanced the detection of unruptured intracranial aneurysms in healthy adults. At our institution, surgical clipping is the first-line treatment for unruptured intracranial aneurysms (UIA). In this study, the differences in neurological and radiological outcomes, as well as cognitive and psychological results, between standard clipping and keyhole clipping for these aneurysms detected via brain docking were evaluated. The study included 131 aneurysms detected via “brain dock.” Of these, 65 were treated with keyhole clipping surgery (keyhole clipping group), and 66 were treated with standard clipping surgery (standard clipping group). Evaluations at 3 months included the National Institutes of Health Stroke Scale, modified Rankin Scale, Mini-Mental State Examination, Hasegawa's Dementia Scale-revised, Beck Depression Inventory, Hamilton Rating Scale for Depression, and radiological abnormalities. The mean operative time and postoperative hospitalization period were significantly shorter in the keyhole clipping group than in the standard clipping group (p < 0.001). Between the groups, no significant differences in postoperative neurological complications or radiological abnormalities were found. The keyhole clipping group demonstrated slightly but significantly better Beck Depression Inventory and Hamilton Rating Scale for Depression scores than the standard clipping group (Beck Depression Inventory, p = 0.046; Hamilton Rating Scale for Depression, p < 0.01). Both the Beck Depression Inventory and Hamilton Rating Scale for Depression scores at 3 months were significantly enhanced (p < 0.001) in the keyhole clipping group. These findings propose that keyhole clipping could be considered a new therapeutic option for small UIA detected via brain docking

Potential Risks and Limited Indications of the Supraorbital Keyhole Approach for Clipping Internal Carotid Artery Aneurysms

Background: Internal carotid artery (ICA) aneurysm may be a good target for supraorbital keyhole clipping. We discuss the surgical indications and risks of keyhole clipping for ICA aneurysms based on long-term clinical and radiologic results. Methods: This was a retrospective analysis of 51 patients (aged 35–75 years, mean 62 years) with ICA aneurysms (mean 5.8 ± 1.8 mm) who underwent clipping via the supraorbital keyhole approach between 2005 and 2017. Neurologic and cognitive functions were examined by several methods, including the modified Rankin Scale and Mini-Mental Status Examination. The state of clipping was assessed 1 year and then every few years after the operation. Results: Complete clipping was confirmed in 45 patients (88.2%), dog-ear remnants behind the clip persisted in 4 patients, and wrapping was performed in 2 patients. Mean duration of postoperative hospitalization was 3.4 ± 6.9 days. The mean clinical follow-up period was 6.6 ± 3.2 years. The overall mortality was 0, and overall morbidity (modified Rankin Scale score ≥2 or Mini-Mental Status Examination <24) was 3.9%. Completely clipped aneurysms did not show any recurrence during the mean follow-up period of 6.3 ± 3.1 years, but the 2 (3.9%) aneurysms with neck remnants showed regrowth. Conclusions: The risk of neck remnant behind the clip blade is a drawback of supraorbital keyhole clipping. The surgical indication requires preoperative simulation and careful checking of the clip blade state is essential. Key words: Clipping, Internal carotid artery, Keyhole surgery, Unruptured cerebral aneurys