Treating vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysms poses challenges because of their complex anatomy. Although endovascular treatment is commonly preferred, direct surgery offers better recovery prospects than endovascular surgery aided by bypass techniques. We present a VA-PICA aneurysm case treated with VA internal trapping, using a PICA-to-PICA bypass without direct clipping. A 64-year-old man presented with complaints of severe headache and was diagnosed with a right VA-PICA wide neck aneurysm. The PICA originated from the neck of the aneurysm. We consulted an endovascular surgeon and opted for direct clipping via the transcondylar fossa approach. During surgery, we secured and followed the right VA, identified the PICA origin, and observed the proximal neck of the aneurysm. However, securing the distal VA was challenging because the dissector was inaccessible. Instead of direct clipping, a PICA-to-PICA bypass was selected following internal trapping. After anastomosis, the proximal PICA was occluded, whereas the small perforating artery was preserved. The next day, internal trapping of the right VA was performed. The patient's postoperative course was uneventful, except for mild dysphagia. Head magnetic resonance imaging revealed a small infarction on the right medulla. Three-dimensional computed tomography angiography revealed perfect PICA-to-PICA bypass patency. The patient was subsequently transferred to a rehabilitation hospital. The patient had no neurological symptoms at the six-month follow-up (Modified Rankin Score = 0). The preoperative feasibility of direct clipping of complex PICA aneurysms while preserving PICA is unpredictable. Various bypass methods, including the PICA-to-PICA bypass, are potential treatment options for complicated VA-PICA aneurysms.

Utilization an in-situ pedicle of the external carotid artery (ECA) as an arterial donor can allow for the successful augmentation or replacement of flow to a large vascular territory. We propose a mathematical model for quantitatively analyzing and grading the suitability of donor and recipient bypass vessels based on a set of anatomical and surgical variables in order to predict which pair has the greatest possibility for success. Using this method, we analyze all of the potential donor-recipient pairs for each ECA donor vessel-including the superficial temporal (STA), middle meningeal (MMA), and occipital (OA) arteries.

The ECA pedicles were dissected in frontotemporal, middle fossa, subtemporal, retrosigmoid, far lateral, suboccipital, supracerebellar, and occipital transtentorial approaches. For each approach, every potential donor-recipient pair was identified, and donor length and diameter were measured as well as depth of field, angle of exposure, ease of proximal control, maneuverability, and length and diameter of the recipient segment. Anastomotic pair scores were determined by adding the weighted donor and recipient.

The best overall anastomotic pairs were OA-vertebral artery (V3, 17.1) and STA-insular (M2, 16.3) and STA-sylvian (M3, 15.9) segments of the middle cerebral artery. Other strong anastomotic combinations were OA- telovelotonsillar (15) and OA- tonsilomedullary (14.9) segments of the posterior inferior cerebellar artery, and MMA-lateral pontomesencephalic segment of the superior cerebellar artery (14.2).

This novel model for anastamotic pair scoring can serve as a useful clinical tool for selecting the optimal donor, recipient, and approach combination that can help facilitate a successful bypass.

The treatment of complex intracranial aneurysms can be challenging with stand-alone open or endovascular techniques, particularly after rupture. A combined open and endovascular strategy can potentially limit the risk of extensive dissections with open-only techniques, and allow for aggressive definitive endovascular treatments with minimized downstream ischemic risk.

Retrospective, single-institution review of consecutive patients undergoing combined open revascularization and endovascular embolization/occlusion for complex intracranial aneurysms from 1/2016 to 6/2022.

Ten patients (4 male [40%]; mean age 51.9 ± 8.7 years) underwent combined open revascularization and endovascular treatment of intracranial aneurysms. The majority of aneurysms, 9/10 (90%), were ruptured and 8/10 (80%) were fusiform in morphology. Aneurysms of the posterior circulation represented 8/10 (80%) of the cases (vertebral artery [VA] involving the posterior inferior cerebellar artery [PICA] origin, proximal PICA or anterior inferior cerebellar artery/PICA complex, or proximal posterior cerebral artery). Revascularization strategies included intracranial-to-intracranial (IC-IC; 7/10 [70%]) and extracranial-to-intracranial (EC-IC; 3/10 [30%]) constructs, with 100% postoperative patency. Initial endovascular procedures (consisting of aneurysm/vessel sacrifice in 9/10 patients) were performed early after surgery (0.7 ± 1.5 days). In one patient, secondary endovascular vessel sacrifice was performed after an initial sub-occlusive embolization. Treatment related strokes were diagnosed in 3/10 patients (30%), largely from involved or nearby perforators. All bypasses with follow-up were patent (median 14.0, range 4-72 months). Good outcomes (defined as a Glasgow Outcomes Scale ≥4 and modified Rankin Scale ≤2) occurred in 6/10 patients (60%).

A variety of complex aneurysms not amenable to stand-alone open or endovascular techniques can be successfully treated with combined open and endovascular approaches. Recognition and preservation of perforators is critical to treatment success.

Occipital artery (OA)-posterior inferior cerebellar artery (PICA) bypass is a challenging procedure and is not frequently performed owing to the difficulty of OA harvest. To facilitate harvest, the intersection between the sternocleidomastoid and splenius capitis (the OA triangle) is used as the anatomical landmark to identify the OA segment that carries the highest risk of damage. This clinical study aimed to demonstrate efficacy and safety of OA harvest using this landmark.

The study included 18 patients who underwent OA harvest using the OA triangle as a landmark for treatment of vertebral artery and PICA aneurysms. Patients were retrospectively evaluated for safety and patency of OA after harvest and OA-PICA bypass.

Of 18 patients with ruptured and unruptured vertebral artery and PICA aneurysms, 13 (72.2%) underwent OA-PICA bypass and 5 (27.8%) did not undergo bypass. The OA was completely harvested without damage in all patients. After harvest, the OA was patent in 17 patients (94.4%) and was occluded in 1 patient owing to vasospasm; this patient then underwent recanalization resulting in good patency of the OA-PICA bypass. The patency rate of the OA-PICA bypass was 100%.

The OA triangle, which is the anatomical landmark of the proximal end of the transitional segment of the OA, facilitated OA harvest using the distal-to-proximal harvest technique with safety and good patency. To the best of our knowledge, this is the first study of OA harvest in clinical cases.

Aneurysms of the vertebrobasilar system remain among the most challenging subsets of aneurysms to treat with an open surgical approach. Since Charles Drake's pioneering work in the 1960s, several advances in microsurgical techniques have improved outcomes and feasibility in the open surgical management of these aneurysms. In parallel, the field of endovascular neurosurgery has provided several safe and effective treatment options. Multiple trials have suggested that endovascular therapy for aneurysms of the vertebrobasilar system is superior to open surgical management in most cases. In some instances, however, open surgical management likely represents a more effective and durable option relative to endovascular therapy. Therefore, continued training of future cerebrovascular specialists in open surgery of vertebrobasilar aneurysms remains crucial. With widespread utilization of endovascular techniques, however, proper exposure of trainees to such aneurysms is growing increasingly difficult. In this review, we discuss the recent advances in the endovascular management of vertebrobasilar aneurysms while also emphasizing the continued importance of open microneurosurgery in such cases.

The patency of cranial bypasses must be carefully evaluated during and after the microsurgical procedure. Although, several imaging techniques are used to evaluate the patency of bypasses, their findings are sometimes difficult to interpret.

The goal of this study was to assess the consistency of different diagnostic modalities for evaluating intracranial bypass patency.

This prospective study included 19 consecutive patients treated with EC-IC or IC-IC bypass for MoyaMoya disease (MMD) or complex/giant aneurysms between June 2016 and June 2018. In the early postoperative period (<7 days), all patients had transcranial Doppler (TCD), CT angiography (CTA) and MRA to demonstrate patency of anastomoses and to confirm exclusion of the aneurysm. When findings of anastomosis patency differed between these techniques, conventional angiography was performed.

All anastomoses were patent on indocyanine green videoangiography at the end of microsurgical procedure. The results of noninvasive postoperative exams were consistent to demonstrate the patency of anastomoses in 13 patients. In 4 patients, a discrepancy in patency of anastomoses arose between TCD, CTA and MRI in the early postoperative period. In 2 other patients, the interpretation of bypass patency remained inconclusive before the decision to occlude the aneurysm. In these 6 patients, a significant edema was noted in 2 cases, a postoperative subdural hematoma in 1 case, a low flow in the anastomosis in 1 case and vasospasm in 2 cases. The anastomosis was patent on the conventional angiography in five patients.

Noninvasive imaging techniques provide useful data about the patency but their findings should be carefully interpreted due to local anatomical, physiological, and pathological factors. In case of discrepant findings, conventional angiography including supraselective catheterization of the donor vessel is suggested.

Dissecting aneurysms of the posterior cerebral circulation can wield significant treatment challenges with devastating clinical outcomes. Despite an expanded therapeutic armamentarium, these vascular lesions remain relatively difficult to diagnose and portend high associated morbidity and mortality.

A ruptured, fusiform, dissecting aneurysm of the mid V4 segment of the right vertebral artery (VA) distal to the posterior inferior cerebellar artery origin resulted in a Hunt and Hess grade 5, Fisher scale score 4 subarachnoid hemorrhage. The lesion incorporated 360 degrees of the vessel wall and extended across an area measuring 11 mm in length and 6.8 mm in width at maximum dimension. The vascular lesion was treated with 2 overlapping Pipeline Embolization Devices.

Digital subtraction angiography demonstrated an origin of the right posterior inferior cerebellar artery mildly stenosed by the dissecting aneurysm. The left VA was markedly hypoplastic. After deployment of 2 overlapping Pipeline Embolization Devices, the aneurysm neck was well covered with appropriate positioning of the stent construct with good apposition to the vessel wall. There was contrast stasis within the aneurysm. The patient was managed with dual antiplatelet therapy. He demonstrated initial clinical and radiographic improvement. However, on the night of the second postprocedure day, the patient succumbed to rerupture of the aneurysm.

The literature posits that nonsaccular, fusiform, and dissecting aneurysms of the vertebrobasilar circulation can be occluded with consistency and success using flow diversion techniques. Endovascular treatment of a ruptured dissecting aneurysm of the VA is technically feasible and can be performed with or without parent artery occlusion. Outcomes following flow diversion of the posterior circulation may depend on the location of the dissection and viability of collateral circulation. In the present case, adequate coverage of the aneurysm did not portend a positive outcome.

Contemporary management of ruptured vertebral artery dissecting aneurysms (VADA) has evolved beyond proximal parent artery occlusion (PPAO) to include endovascular trapping (ET) of the diseased segment and vessel preserving stent treatments. The aim of this retrospective cohort study was to assess the outcomes of patients with ruptured VADAs who underwent endovascular management with trapping of the diseased segment as the first-line treatment approach.

We evaluated an institutional database of patients with ruptured VADAs who were treated at Auckland City Hospital from 1998 to 2017. Baseline and outcomes data were analyzed. High-grade SAH was defined as a World Federation of Neurological Surgeons or a Hunt and Hess grade of IV-V. Favorable outcome was defined as a modified Rankin Scale of 0-2.

The study cohort was comprised of 45 ruptured VADA patients with a mean age of 50 years. The mean follow-up duration was 12.9 months. ET of the diseased segment was performed in 32 cases (71.1%), PPAO of the VA was performed in 12 cases (26.7%) and reconstruction using a flow diverting stent was performed in 1 case (2.2%). The overall procedural complication rate was 13%, including procedural neurological morbidity in 4.4%. At last follow-up, no further aneurysm filling was seen in any case, and 77.8% had a favorable outcome.

ET affords a favorable risk to benefit profile for patients with ruptured VADAs. ET remains a reasonable option for ruptured VADAs in patients with sufficient collateral supply to the vertebrobasilar system.

Although vertebral artery (VA) dissecting aneurysms are treated by direct or endovascular surgery, some disadvantages are associated with each surgery. Therefore, the type of surgery should be selected based on the condition of the aneurysm. We performed aneurysm trapping by endovascular surgery via the contralateral VA after proximal direct ligation with bypass to prevent complications as well as achieve complete treatment.

We attempted to insert a distal clip to achieve complete trapping of the ruptured VA dissecting aneurysm after proximal ligation with occipital artery-posterior inferior cerebellar artery (PICA) anastomosis; however, the operative field was limited by the existence of lower cranial nerves, brain swelling, and tortuosity of VA. Therefore, we performed the aneurysmal trapping by endovascular surgery via contralateral VA just after the direct surgery.

This technique can provide complete resolution without any complications, particular in the case of bleeding VA dissecting aneurysms that have a PICA origin and are located in the high or contralateral position.