Paraclinoid aneurysms: Outcome analysis and technical remarks of a microsurgical series

Endovascular Treatment and Microsurgical Clipping for the Management of Paraclinoid Intracranial Aneurysms: A Systematic Review and Meta-Analysis

OBJECTIVE

We aimed to compare the efficacy and safety of microsurgical clipping versus endovascular treatment (EVT) for paraclinoid aneurysms.

METHODS

A systematic search for studies including patients with paraclinoid aneurysms treated with a microsurgical or endovascular technique was conducted in 6 databases from inception to February 2022. Efficacy outcomes included complete angiographic occlusion at last follow-up, favorable functional outcome, and recurrence of the aneurysm. For safety, we assessed a composite of intraoperative and postoperative complications. Data were pooled using a random-effects model.

RESULTS

A total of 95 studies including 6711 patients, 3029 in the surgical group and 3682 in the EVT group were found. Pooled rates of complete occlusion were 94% (95% CI 91%-96%; I2 = 0%) in the surgical group and 69% (95% CI 63%-74%; I2 = 79%) in the EVT group, respectively. The favorable functional outcome rate was 86% (95% CI 76%-92%; I2 = 72%) with surgical treatment and 95% (95% CI 92%-97%; I2 = 61%) with EVT. The rate of aneurysm recurrence with surgical treatment was 1% (95% CI 0%-4%; I2 = 0%) and 12% (95% CI 9%-16%; I2 = 57%) with EVT. The composite safety outcome rate in the surgical group was 24% (95% CI 18%-30%; I2 = 90%) and 10% (95% CI 8%-13%; I2 = 71%) in the EVT group.

CONCLUSIONS

Our findings suggest that microsurgical clipping seems to have a higher efficacy than EVT in terms of angiographic occlusion and aneurysm recurrence; however, EVT seems to be safer in terms of intraoperative and postoperative complications. Considering the heterogeneity and low-level evidence of the data available, further prospective randomized studies are warranted to confirm our findings.

Optic Foraminotomy versus Anterior Clinoidectomy for Small Superior-Projecting Paraclinoid Aneurysms: Visual and Angiographic Outcome Evaluation

INTRODUCTION

Optic foraminotomy (OF) has been recently proposed as an alternative to anterior clinoidectomy (AC) for selected types of paraclinoid aneurysms. In this study, OF and AC were compared for small superior-projecting paraclinoid aneurysms assuming visual and angiographic results as outcome measures. Indications for OF are also discussed.

METHODS

Data of patients who underwent surgery for a paraclinoid aneurysm in the last 10 years were collected across 3 tertiary hospitals. Small to regular-size and superior projecting aneurysms were sorted. Multiple and complex aneurysms were excluded. Records of patients who went through OF were compared with those of patients who underwent AC. Neurologic outcome was reported as a modified Rankin Scale. Aneurysm complete occlusion rate and rate of approach-related worsened vision were selected as outcome measures of efficacy and safety, respectively, of the OF versus AC. Unpaired t test and χ² test were used for numerical and categorical variables, respectively. A P value less than 0.05 was considered statistically significant.

RESULTS

OF and AC groups involved 18 and 25 patients, respectively. Complication rate, overall neurologic outcome, rate of approach-related worsened vision, and complete occlusion rate did not differ between the groups. The average follow-up was 51 ± 34 and 60 ± 41 months in the OF and AC groups, respectively.

CONCLUSIONS

Compared to AC, OF did not show either a higher rate of approach-related worsened vision or a lower aneurysm complete occlusion rate. OF can be considered a valid alternative to the AC for small superior-projecting dorsal ICA wall paraclinoid aneurysms.

Microneurosurgical management of aneurysms of the A1 segment of the anterior cerebral artery: Anatomy and surgical technique

Background:

Aneurysms of the A1 segment of the anterior cerebral artery (ACA) are rare and have characteristics differentiating them from other intracranial aneurysms. Their microsurgical management is challenging and requires different strategies. In this article, we review the surgical anatomy of the A1 segment of the ACA with cadaveric dissections and describe the microsurgical management of complex A1 aneurysms with illustrative cases.

Methods:

A right pterional craniotomy and Sylvian dissection were performed on a formalin-fixed and silicone-injected cadaver head to depict the key anatomic structures and surgical corridors for microsurgical clipping of A1 segment aneurysms. The microneurosurgical management of ruptured and unruptured aneurysms of the A1 segment of the ACA is described with case illustrations.

Results:

The A1 segment of the ACA can be subdivided into proximal, middle, and distal subsegments, the former having abundant perforating branches. Both patients treated with microsurgical clipping had excellent and durable outcomes and postoperative cerebral angiograms showed complete aneurysm occlusion.

Conclusion:

Small A1 aneurysms may require early treatment as their rupture risk appears to be higher. A1 aneurysms are usually embedded in perforators, especially those arising from the proximal A1 subsegment, and require careful distal to proximal microdissection and strategic placement of the aneurysm clip blades. The approach, arachnoid dissection, and angles of attack are carefully planned after accounting for the aneurysm dome projection, precise location of the aneurysm neck and perforators, and the presence or absence of subarachnoid hemorrhage.