Although the cases reported so far are all caused by SAH, there are no reports of unruptured cases, so the natural history of BAPA is not clear .Because of the small size of the aneurysm,it is difficult to complete superselective artery embolization Because of the small size of the aneurysm, On the other hand,The aneurysm is located at the deep end, which makes it difficult to expose.Ischemic events caused by difficulties in perforating perforating branches are all problems to be considered when choosing a treatment plan.However,some cases were found to be self-healing during follow-up, so conservative observation under DSA follow-up was the preferred method in many reports.Rehaemorrhage occurred in 6 of the 21 conservative cases reported in the literature (28.57%), of which 2 received microsurgery and 2 received endovascular intervention.(1 cases were treated with coil embolization, and 1 case were implanted with flow diverter).2 cases remained conservative.Of the 4 patients receiving intervention, only 1 recovered well, and the other 3 had neurological dysfunction of varying degrees due to perforator ischemic events.2 patients who received conservative treatment recovered well.This result proves that the effect of active intervention may not be better than conservative observation[5, 6, 11, 20, 24].
Traditional microsurgical clipping is not the first choice in BAPA.Sanchez-Mejia et al. believed that such lesions usually had no neck of aneurysm, or even a type of vesicular aneurysm, which should be isolated along with the perforating branch of the aneurysmal artery ,and the operation of proximal basilar artery control is also very difficult.We had planned to design a three-dimensional printing model before microsurgical clipping of aneurysms.However, a more backward approach to the inferior temporal bone is needed for direct observation of aneurysms during simulated surgery, which increases the risk of injury to the Labbe vein.And the depth of entry is above 7 cm,The surrounding nervous and vascular structures cause narrow operation space.A longer conventional straight aneurysm clip is needed to ensure that the clip does not occlude the field of view, and therefore does not guarantee the exact clipping of the aneurysm and preservation of the perforating artery.(Fig. 2).
The difficulty of endovascular interventional therapy is that superselective microaneurysms with microcatheters are prone to rupture and bleeding, and the perforating arteries are too small to be effectively protected.Of the 3 cases reported in the literature with coils and 2 cases with Onyx embolization, only one had a good recovery from distal perforator aneurysms of the main basilar artery and the rest had hemiplegia of varying degrees caused by perforator ischemic events[9, 13, 20].Therefore, although it has been reported that the perforator artery as the parent artery can be compensated, whether it can be safely occluded remains to be discussed.Another option to consider is stent placement in the basilar artery.The hemodynamic study of aneurysm model showed that the blood flow velocity, eddy current and wall shear stress in the aneurysm cavity were significantly changed after the stent was implanted into the aneurysm neck.And the denser the mesh, the greater the impact.accordingly,FD seems to be an ideal choice, but this is not the case.The incidence of perforating infarction after posterior circulation aneurysms treated with FD was 14%.Only one of the five FD BAPAs (4 with Pipeline and 1 with SILK) in the literature had no ischemic events.It is suggested that excessive hemodynamic changes may be a risk factor for perforator occlusion[15, 19, 24].To this end, more patients try to choose the conventional stent-in-stent technique (Enterprise, Neuroform, Leo) for treatment.Half of the 10 reported patients had no definite ischemic events (the other 5 had no definite prognosis), suggesting that this technique may be a better choice for BAPA intervention [12, 21, 26] .However, whether antiplatelet therapy will increase acute hemorrhagic complications remains to be seen in larger cases and longer-term follow-up.
Jiang Y et al. Reported a new method for the treatment of intracranial small aneurysms.When microcatheter is difficult to implant,Only conductive micro-wires (such as Traxcess14) were implanted into the aneurysm cavity, and then electrocoagulated to occlude the aneurysm.They reported a case of proximal basilar artery perforator aneurysm. The aneurysm was not only obscured by this method, but also retained the parent artery.This approach provides us with a new concept that seems promising to make BAPA's endovascular treatment process more convenient, safe, and cost-effective. However, there is no long-term follow-up study to determine whether the intraluminal thrombosis is stable enough.