1Department of Neurosurgery, Asahikawa Red Cross Hospital, Asahikawa; and.
2Department of Neurosurgery, Sapporo Teishinkai Hospital, Sapporo, Japan.
J Neurosurg. 2020 Apr 10;134(3):1165-1172. doi: 10.3171/2020.1.JNS192728. Print 2021 Mar 1.
During surgical clipping of internal carotid artery (ICA)-posterior communicating artery (PCoA) aneurysms, proximal vascular control (PVC) is difficult to achieve in some cases because of variations in the anatomy of this type of aneurysm and its parent arteries. The authors investigated morphometric features that may be predictive for the necessity of anterior clinoidectomy (ACL) or cervical ICA exposure for PVC.
The authors retrospectively reviewed 65 patients with an ICA-PCoA aneurysm treated with clipping during the previous 3 years. The factors considered for assessing the difficulty of attaining PVC included the following: the maximum diameter of the aneurysm; the distance between the tip of the anterior clinoid process (ACP) and the proximal aneurysmal neck; the presence of calcification at the ophthalmic segment of the ICA; and the angles between the communicating segment of the ICA and the ophthalmic segment of the ICA and a line perpendicular to the cranial base, which reflect the tortuosity of the ICA. These parameters were measured based on preoperative CTA results.
In a total of 21 patients (32.3%), PVC was difficult to perform with the usual pterional approach. In 6 patients, temporary artery occlusions (TAOs) were difficult to achieve because of severe atherosclerotic wall changes in the ophthalmic segment of the ICA. For 15 patients, the ACPs overhanging the ophthalmic segment of the ICA obstructed the ability to secure a space for TAO. In the 21 patients with PVC difficulty, ACL alone, cervical ICA exposure alone, and both ACL and cervical ICA exposure were conducted in 6, 8, and 7 patients, respectively. Multivariate analysis with binary logistic regression revealed that the maximum diameter of the aneurysm (p = 0.041), the distance between the proximal neck of the aneurysm and the ACP tip (p = 0.002), and calcification of the ICA ophthalmic segment (p = 0.001) were significant predictive factors for difficulties with PVC. A receiver operating characteristic curve analysis revealed that a distance between the proximal aneurysmal neck and the ACP tip of ≤ 5.4 mm was the best cutoff value for predicting the difficulty of attaining PVC (area under the curve 0.800, sensitivity 80.0%, specificity 80.0%).
A short distance between the proximal aneurysmal neck and the ACP tip and the presence of calcification at the ophthalmic segment of the ICA on preoperative CTA are helpful for predicting the difficulty of achieving PVC.
在外科夹闭颈内动脉（ICA）-后交通动脉瘤（PCoA）时，由于此类动脉瘤及其母动脉的解剖变异，近端血管控制（PVC）有时难以实现。作者研究了可能预测前床突切除术（ACL）或颈内动脉（ICA）暴露以实现 PVC 必要性的形态学特征。
作者回顾性分析了过去 3 年期间接受夹闭治疗的 65 例 ICA-PCoA 动脉瘤患者。评估实现 PVC 难度的因素包括：动脉瘤的最大直径；前床突尖端（ACP）与近端瘤颈之间的距离；ICA 眼段的钙化；以及 ICA 交通段与垂直于颅底的线之间的夹角，这些参数反映了 ICA 的迂曲程度。这些参数基于术前 CTA 结果进行测量。
共有 21 例患者（32.3%）采用常规翼点入路难以实现 PVC。在 6 例患者中，由于 ICA 眼段严重的动脉粥样硬化壁改变，难以实现临时动脉闭塞（TAO）。对于 15 例患者，ACP 突入 ICA 眼段，阻碍了 TAO 空间的建立。在 21 例存在 PVC 困难的患者中，分别有 6 例、8 例和 7 例单独行 ACL、单独行颈内动脉暴露以及同时行 ACL 和颈内动脉暴露。二元逻辑回归的多变量分析显示，动脉瘤的最大直径（p=0.041）、动脉瘤近端颈部与 ACP 尖端之间的距离（p=0.002）和 ICA 眼段钙化（p=0.001）是 PVC 困难的显著预测因素。受试者工作特征曲线分析显示，动脉瘤近端颈部与 ACP 尖端之间的距离≤5.4mm 是预测实现 PVC 困难的最佳截断值（曲线下面积 0.800，灵敏度 80.0%，特异性 80.0%）。
术前 CTA 显示动脉瘤近端颈部与 ACP 尖端之间的距离较短以及 ICA 眼段存在钙化有助于预测实现 PVC 的难度。
