How I do it: safe resection of a complex type 3 foramen magnum meningioma with dorsal displacement of the neurovascular bundle.

BACKGROUND: We describe techniques for safe resection of a Type 3 foramen magnum meningioma with dorsal displacement of the accessory nerve rootlets and vertebral artery which limits ventral access to the tumor. METHOD: Partial sectioning of the accessory nerve rootlets may help create larger working space. Topical lidocaine placement on the rootlets of the spinal accessory nerve may mitigate trapezius muscle contraction and facilitates further progress throughout tumor resection. CONCLUSION: Creating safe working corridors between the lower cranial nerves through mobilization or partial sectioning of rootlets in the case of CN XI facilitates tumor resection through a far lateral approach.

[Microsurgery for Vertebral and Posterior Inferior Cerebellar Artery Aneurysms via Lateral Suboccipital Craniotomy].

Among ruptured intracranial aneurysms, aneurysms of the vertebral artery(VA) and posterior inferior cerebellar artery(PICA) are relatively rare, and they exhibit distinct characteristics. These include: 1) a high frequency of diverse aneurysmal morphologies, such as fusiform or dissecting aneurysms; 2) proximity to the lower cranial nerves; 3) the presence of perforators to the medulla oblongata; and, 4) obstruction to the surgical approach by specific bony structures, such as the occipital condyle and jugular tubercle. Consequently, these aneurysms often require interventions that are more complex than simple clipping or coiling, which is typical for anterior circulation aneurysms. Interventions include skull base techniques such as the far-lateral approach and revascularization procedures such as occipital artery(OA)-PICA bypass. Despite these complexities, the rarity of these aneurysms and the recent advancements in endovascular procedures pose challenges for young neurosurgeons in acquiring adequate microsurgical experience. This narrative review addresses the clinical features of VA and PICA aneurysms, the history and variations in the lateral suboccipital approach for these aneurysms, and several bypass techniques for reconstructing the PICA. Lastly, we illustrate our current microsurgical practices through a case presentation accompanied by a surgical video showcasing both the far-lateral approach and the OA-PICA bypass.

[Repeated Bow hunter's stroke by artery-to-artery embolism from the vertebral artery dissecting aneurysm formed by head rotation: A case report].

A 55-year-old woman suffered from diplopia and occipital pain after shoveling snow. She was diagnosed with the right vertebral artery dissecting aneurysm at the level of the axial vertebra and repeatedly had cerebral infarctions in the posterior circulation. She had subluxation of the atlantoaxial vertebra as an underlying disease. Right vertebral angiogram with the head rotated to the left showed the right vertebral artery occlusion and left vertebral angiogram with the head rotated to the right showed stenosis at the C1-C2 level, leading to the diagnosis of Bow hunter's stroke. After wearing a cervical collar and taking 100 |mg of aspirin, she had no recurrence of cerebral infarction and later underwent C1-C2 posterior fusion to prevent the recurrence of cerebral infarction. She finished taking aspirin 6 months after the surgery, and there has been no recurrence of cerebral infarction. We report here a case of Bow hunter's stroke, a rare disease, with good clinical outcomes after C1-C2 posterior fusion.

Aberrant course of the right petrous internal carotid artery (ICA) associated with right type 1 proatlantal artery and bilateral occipital arteries arising from the ICA diagnosed by computed tomography angiography.

PURPOSE: To describe a case of multiple extremely rare cervical arterial variations. METHODS: A 55-year-old man with a tentative diagnosis of right internal carotid artery (ICA) stenosis was examined using computed tomography (CT) angiography for the evaluation of vascular lesions in the neck and head region. A 64-slice CT machine was used. RESULTS: On CT angiography, there was laterally located and narrowed petrous segment of the right ICA, indicative of aberrant course of the petrous ICA. Right vertebral artery (VA) was small in caliber and a relatively large anomalous artery arose from the proximal right ICA. This anomalous artery entered the posterior fossa via the foramen magnum, indicative of a type 1 proatlantal artery. Right occipital artery (OA) arose from the proximal ICA. The left OA also arose from the proximal ICA. CONCLUSION: An aberrant course of the petrous ICA is an extremely rare arterial variation which is formed by segmental agenesis of the cervical ICA, and the collateral channel passes through the middle ear cavity. It can be dangerous during middle ear surgery. The type 1 proatlantal artery is also an extremely rare arterial variation formed by the persistence of the proatlantal intersegmental artery. It is clinically significant because of its unique blood flow from the carotid system to the vertebrobasilar system. The OA rarely arises from the proximal ICA. Identification of these cervical arterial variations before surgery and vascular intervention are important to avoid complications during the procedure.

Indications, operative techniques, and outcomes of occipital artery-vertebral artery bypass: an institutional series.

PURPOSE: Posterior circulation cerebral bypasses often show higher risks and lower patency. Only few reports discussed occipital artery (OA)-vertebral artery (VA) bypasses. We present our illustrative cases to address current gaps in the literature on OA-VA bypass. METHODS: A single-center retrospective review was conducted to include all institutional cases of OA-VA bypass, discussing the technique and outcomes. RESULTS: Four institutional cases undergoing a total of 5 bypasses were evaluated, including 3 males and 1 female, with median age of 65 years (range, 62-73). All patients had vertebrobasilar insufficiency (VBI) with recurrent strokes/TIAs due to intracranial atherosclerosis, leading to unilateral VA stenosis with contralateral occlusion (1, 25%), bilateral VA stenosis (1, 25%) or occlusion (1, 25%). Medical management included aspirin for all cases (100%), with clopidogrel in 3 (75%). Surgery was performed through a far lateral approach, connecting the OA to the VA-3 segment, with no inter-positional graft. One patient underwent contralateral OA-VA bypass 6 months after the prior surgery due to worsening of the contralateral VA stenosis. Bypass patency was confirmed in all cases with post-operative angiography. All patients had clinical improvement, with one case of wound dehiscence managed conservatively. All patients were alive at last follow-up (median 7.0 months; range: 1.5-18). CONCLUSION: OA-VA bypass is a challenging yet effective strategy in selected patients with VBI. Current literature lacks unique definitions of surgical indications and techniques, which we addressed in our series. Surgical education should focus on expanding the microsurgery anatomy knowledge.

[Penetrating Lung Injury Complicated by Hemodynamic Cerebral Infarction].

We encountered a case in which emergency surgery was performed for a penetrating lung injury complicated by a hemodynamic cerebral infarction. A 45-year-old man sustained a chest injury due to a scattered piece of metal and was admitted to a nearby hospital. He was confirmed to have hemorrhagic shock due to a right hemopneumothorax, and a chest tube was inserted he was transferred to our hospital. Chest radiography and computed tomography (CT) revealed a metal fragment in the right lung and confirmed the diagnosis of a penetrating lung injury due to a foreign body. The patient also presented with total blindness of an unknown etiology. Emergency surgery was performed to treat the injury and remove the foreign body. A large amount of blood and hematoma were removed from the right thoracic cavity, and a metal fragment was found in the lower lobe of the right lung. After removing the foreign body, pulmonary suturing was performed. On the following day, head magnetic resonance imaging revealed multiple cerebral infarctions in the bilateral occipital lobes, left frontal lobe, and left cerebellar hemisphere. However, no vascular occlusion or thrombus was found, and the patient was diagnosed with hemodynamic cerebral infarction due to hemorrhagic shock.

Does ponticulus posticus affect vertebral artery diameter.

PURPOSE: Ponticulus Posticus, atlantooccipital ligament ossification-induced anomaly, surrounds the vertebral artery and the first cervical nerve root. It is believed to wrap around the first cervical nerve root and the vertebral artery, causing compression. We hypothesized that it would also reduce the diameter of the vertebral artery. METHODS: Between January 1, 2022, and December 31, 2022, cervical spine CT scans taken for any reason were retrospectively reviewed. The images of 1365 patients suitable for evaluation were evaluated by two expert radiologists in 3 dimensions. Among patients with PP, those who underwent cervical angiography were identified for vertebral artery diameter measurement. RESULTS: The average age of the 1365 individuals included in the study (732 males, 633 females) was 55.78 (± 18.85) with an age range of 1-96. Among this group, PP was detected in 288 individuals, resulting in a total prevalence of 21.1%. Right and left vertebral artery diameters were significantly lower in patients with complete PP compared to the absent group (p < 0,001, p < 0,001, respectively). Additionally, it was observed that width and height diameters and artery diameters were positively correlated in patients with Complete PP. CONCLUSIONS: Ponticulus posticus can cause vertebrobasilar insufficiency by reducing the diameter of the vertebral artery. Therefore, imaging and detailed evaluation of this region are important in symptomatic patients.

A scarce combination of arterial variants: an occipital artery originating from the internal carotid artery associated with a linguofacial trunk.

The occipital artery (OA) typically originates from the external carotid artery (ECA). Variations of the ECA has been well described in the current literature, while the OA is a relatively stable vessel, and its variations are uncommon. In the current case report, an aberrant OA has been found coexisting with a linguofacial trunk (LFT) on the right hemineck of a 51-year-old male patient. The OA was identified originating from the cervical internal carotid artery (ICA) at the level of the second cervical vertebra (C2). On the ECA, the lingual and facial arteries were emanating in common, as LFT. The left hemineck of the patient was free of variations. The current coexistence of arterial variants has been reported only once previously; therefore, the current case corresponds to the second case in the English literature. The aberrant OA origin from the ICA has been estimated with a pooled prevalence of 0.37%, while the origin at the C2 level and from the anterior surface of the ICA corresponds to a very rare variation. Additionally, the LFT is one of the most common trunk that can be found on the ECA. Interventional radiologists and surgeons must be aware of common and uncommon variation to avoid iatrogenic lesion.

Delayed traumatic intracranial aneurysms: literature review and case series.

Traumatic intracranial aneurysm (TICA) is a rare and aggressive pathology that requires prompt treatment. Nevertheless, early vascular imaging following head trauma may yield falsely negative results, underscoring the importance of subsequent imaging within the first week to detect delayed TICAs. This study aims to report our experience with delayed TICAs and highlight the clinical importance of repeated angiographic screening for delayed TICAs. In this retrospective analysis, we evaluated patients managed for a TICA at a tertiary care teaching institution over the last decade. Additionally, we conducted a systematic review of the literature, following the PRISMA guidelines, on previously reported TICAs, focusing on the time lag between the injury and diagnosis. Twelve delayed TICAs were diagnosed in 9 patients. The median time interval from injury to diagnosis was 2 days (IQR: 1-22 days), and from diagnosis to treatment was 2 days (IQR: 0-9 days). The average duration of radiological follow-up was 28 ± 38 months. At the final follow-up, four patients exhibited favorable neurological outcomes, while the remainder had adverse outcomes. The mortality rate was 22%. Literature reviews identified 112 patients with 114 TICAs, showcasing a median diagnostic delay post-injury of 15 days (IQR: 6-44 days), with 73% diagnosed beyond the first week post-injury. The median time until aneurysm rupture was 9 days (IQR: 3-24 days). Our findings demonstrate acceptable outcomes following TICA treatment and highlight the vital role of repeated vascular imaging after an initial negative computed tomography or digital subtraction angiography in excluding delayed TICAs.

Bow hunter's syndrome due to an anomalous right vertebral artery origin and contralateral absence: a case report and literature review.

BACKGROUND: Bow Hunter's syndrome (BHS), also known as rotational vertebral artery occlusion (RVAO), is a rare condition characterized by dynamic vertebrobasilar insufficiency due to position-dependent occlusion of the vertebral artery (VA). In the existing literature, most cases of BHS are attributed to osteophytic compression originating from the occipital condyle or within the transverse foramen, often accompanied by anatomical abnormalities of the VA. However, cases presenting solely with VA anomalies in the absence of any cervical vertebral structural abnormality are rare. This case report presents a unique instance of BHS in a 56-year-old male, attributed to the anomalous origin of the right VA and the absence of the left VA, without cervical structural abnormalities. CASE PRESENTATION: The patient exhibited symptoms like episodic dizziness and vertigo, which were exacerbated by rightward head rotation and alleviated upon returning to a neutral position. Diagnostic evaluation, including digital subtraction angiography, revealed that the right VA originated from the right common carotid artery and compression-induced stenosis of the right VA during head rotation. Conservative management, including avoidance of certain head movements and anti-arteriosclerosis medication, led to symptom resolution over a two-year follow-up period. CONCLUSIONS: This report contributes to the understanding of BHS by highlighting a rare vascular anomaly presentation and incorporates a review of 14 similar case reports in the literature describing that an anatomical abnormality of the VA is mainly responsible for the pathology of BHS in the absence of cervical vertebral anomalies, thus emphasizing the need for careful diagnostic and management strategies.

The impact of an anomalous third segment of the vertebral artery on bypass surgery: a case report and literature review.

The horizontal part of the third segment (V3) of the vertebral artery (VA) is a critical anastomotic site for bypass procedures involving either donor or recipient vessels. It is rare for the V3 segment to deviate from its typical course of passing through the atlanto-transverse foramen. V3 anomaly encountered in occipital artery (OA)-V3 bypass surgery has not been previously reported. Here, we present a case involving a patient undergoing bypass surgery due to recurrent post-stent occlusion at the first segment (V1) of the left VA. During the operation, it was noted that the V3 horizontal segment could not be identified within the left VA groove, leading to initial suspicion of left V3 disuse atrophy attributed to prolonged chronic ischaemia. Consequently, there was a need to modify the operative method and to transition from an OA-V3 bypass to an OA-posterior inferior cerebellar artery bypass. Post-operative computed tomography angiography confirmed that indeed, the left V3 did not traverse through the transverse foramen of the atlas and instead entered the dural membrane between the first cervical vertebra (C1) and the second cervical vertebra (C2).

Primary central nervous system vasculitis with intracranial aneurysm.

BACKGROUND: Unruptured intracranial aneurysms (UIAs) are rarely reported in primary central nervous system vasculitis (PCNSV). In this study we described the clinical findings, response to therapy, and outcomes of UIA in a large cohort of PCNSV patients. METHODS: We retrospectively studied 216 consecutive patients with PCNSV, selected by predetermined diagnostic criteria, who were seen during a 40-year period. UIAs were identified on cerebral angiography. The clinical, laboratory, radiologic and pathologic findings, management, and outcomes of patients with UIA were described and compared with those without UIA. RESULTS: 12/216 (5.5 %) PCNSV patients had at least one UIA. Two patients underwent biopsies; one yielded negative results, while the other showed necrotizing vasculitis. Eleven patients had evidence of UIA on angiogram at diagnosis. One patient developed an aneurysm during the follow-up associated with a worsening of vasculitic radiological findings. The most common presenting symptom for PCNSV in the setting of UIA was headache (67 %), followed by persistent neurologic deficit or stroke (50 %). Most patients with UIA presented with multiple cerebral infarcts on MRI (67 %), one patient had subarachnoid hemorrhage, and one left parieto-occipital intracerebral hematoma, both unrelated to the aneurysm. Black blood imaging was performed in 4 patients and 2 showed segmental circumferential mural enhancement involving multiple vessels. Two patients had 2 UIAs, while the other 10 had 1. The most frequent UIA location was internal carotid artery (50 %), followed by anterior cerebral artery (21 %). Ten of the UIAs were < 5 mm in diameter, and 3 were 5-7 mm in diameter; the size was not available for one. All UIAs were unchanged in size and configuration during follow-up (median: 18.5 months; range 1-151 months) and no new aneurysms were detected. Compared to the 204 patients with PCNSV without a UIA, no significant clinical differences were observed, except for a reduced disability at last follow-up (p = 0.038). CONCLUSIONS: UIAs uncommonly occur in PCNSV.

[External Carotid Artery:Essential Knowledge of the External Carotid Artery Required for Neuroendovascular Surgery, with a Focus on the Middle Meningeal Artery and Occipital Artery].

The perfusion territory of the external carotid artery is often underestimated; however, this blood vessel forms abundant "dangerous anastomoses" with the internal carotid and vertebral arteries. An understanding of these vascular anastomoses is crucial to ensure safe cerebrovascular interventions. There are several important aspects of the middle meningeal artery that should be considered, including anastomoses with the anterior(frontal)branch and ophthalmic artery through the sphenoidal artery(recurrent meningeal artery)and meningolacrimal artery. Additionally, the blood supply to the facial nerve via branches of the petrosal branch, such as the superior tympanic artery, and the formation of the facial arcade by the superior tympanic and stylomastoid arteries, which often originate from the posterior auricular artery, is significant. The occipital artery demonstrates rich anastomoses with vessels, such as the ascending pharyngeal and vertebral arteries, forming what is known as the pharyngo-occipital system.

Occipital artery to vertebral artery bypass for treatment of bilateral vertebral artery occlusion with QMRA as an adjunct to diagnostic assessment.

PURPOSE: Stroke, the second leading cause of death globally, often involves ischemia in the vertebrobasilar territory. This condition is underexplored, despite significant morbidity and mortality risks. The purpose of this study is to present a case of occipital artery to V3 segment vertebral artery bypass, emphasizing the role of quantitative magnetic resonance angiography (qMRA) in assessing flow and guiding surgical intervention. METHODS: A 66-year-old man with bilateral vertebral artery occlusion presented acute symptoms. qMRA was employed to evaluate flow dynamics and determine the feasibility of a flow augmentation bypass surgery. The occipital artery to left vertebral artery bypass (OA-to-VA) was performed, utilizing an inverted hockey-stick incision and an antegrade inside-out technique. The patency of the bypass was confirmed using both Doppler probe and Indocyanine green. RESULTS: Postoperative assessments, including computed tomography angiography (CTA) and qMRA, demonstrated the patency of the bypass with improved flow in the basilar artery and left vertebral artery. The patient's condition remained stable postoperatively, with residual peripheral palsy of the left facial nerve. CONCLUSION: In conclusion, the presented case illustrates the efficacy of the OA-to-VA bypass in addressing symptomatic bilateral vertebral artery occlusion. The study underscores the pivotal role of qMRA in pre- and postoperative assessments, providing noninvasive flow quantification for diagnostic considerations and long-term follow-up in patients with vertebrobasilar insufficiency.

Impact of ischemic stroke topography on early clinical outcome of basilar artery occlusion: a retrospective study.

OBJECTIVES: Basilar artery occlusion (BAO) may be etiologically attributed to embolism or in situ thrombosis due to basilar stenosis (BS). Patients with BAO due to BS (BAOS) are known to have worse outcomes than patients with embolic occlusions (BAOE). BAOS occurs more proximally in the basilar artery (BA) than BAOE. We hypothesize that differing brain stem infarct patterns contribute to outcome differences between these stroke etiologies. METHODS: This retrospective study includes 199 consecutive patients with BAO who received endovascular treatment at a single center. Final infarction in brain parenchyma dependent on the posterior circulation was graded semiquantitatively on magnetic resonance imaging (MRI). Associations to underlying stenosis and angiographic and clinical outcome variables were tested. The primary endpoint was early good clinical outcome (EGCO, mRS score ≤ 3 at discharge). RESULTS: Infarct extension of the medulla oblongata (OR = 0.25; 95% CI = 0.07-0.86; p = 0.03), the inferior pons (OR = 0.328; 95% CI = 0.17-0.63; p = 0.001), the superior pons (OR = 0.57; 95% CI = 0.33-0.99; p = 0.046), and the occipital lobes (OR = 0.46; 95% CI = 0.26-0.80; p = 0.006) negatively predicted EGCO. Infarct extension for other posterior-circulation-dependent brain regions was not independently associated with unfavorable early outcomes. Patients with BAOS had more proximal occlusions and greater infarct volumes in the inferior brain stem. Successful reperfusion (mTICI 2b-3) occurred more often in patients with BAOE than in BAOS (BAOE: 131 (96.3%); BAOS: 47 (83.9%), p = 0.005). CONCLUSION: Unfavorable early outcomes in patients with BAOS may be explained by a higher likelihood of inferior brain stem infarcts and lower rates of reperfusion success. CLINICAL RELEVANCE STATEMENT: Basilar artery occlusion due to underlying stenosis is associated with a poorer prognosis than that caused by embolism; these results suggest that aggressive endovascular therapy, usually involving the placement of a permanent stent, may be warranted in these patients. KEY POINTS: Inferior brain stem and occipital infarcts are prognostically unfavorable in basilar artery occlusion. Basilar artery occlusion due to stenosis occurs more proximally and is associated with worse outcomes. Differentiating etiologies of basilar artery occlusion may influence how aggressively treated the occlusion is.

[A case of suspected vertebral artery stump syndrome assessed by CT angiography].

A 55-year-old man developed ischemic stroke in the bilateral cerebellar hemispheres and bilateral occipital lobes. He was admitted to our hospital 17 months later with recurrent ischemic stroke in the posterior circulation. The left vertebral artery (VA) was occluded on brain magnetic resonance angiography but was visualized with a delay on continuous three-phase CT angiography (CTA). Conventional angiography confirmed a to-and-fro blood flow pattern at the distal end of the left VA, therefore the patient was diagnosed with VA stump syndrome (VASS). VASS is a recurrent posterior circulation ischemic stroke caused by thrombi in an occluded unilateral VA. VASS should be suspected in patients with unilateral VA occlusion and repeated posterior-circulation ischemic stroke. The diagnostic criteria for VASS include confirmation of VA occlusion and the presence of an antegrade flow component at the distal end. In this case, the presence of collateral circulation in the VA was suspected based on CTA findings, leading to the diagnosis of VASS. It was thus suggested that devising the imaging method of CTA may help diagnose VASS.

The application value of 3D ASL in evaluating the effectiveness of stent implantation for vertebrobasilar artery stenosis.

OBJECTIVE: To evaluate the effect of stent implantation for vertebrobasilar artery stenosis，by using 3D arterial spin labeling (3D ASL) technique. METHODS: A retrospective analysis was conducted on the clinical and 3D ASL data of 48 patients who underwent vertebral-basilar artery stenting. Post-labeling delay times (PLD) of 1.5 s and 2.5 s were chosen, and the average regional cerebral blood flow (rCBF) values were measured in nine brain regions of the posterior circulation: bilateral thalamus, bilateral occipital lobes, bilateral cerebellar hemispheres, midbrain, pons, and medulla. The 48 patients were divided into two groups based on the presence or absence of acute ischemic stroke in the posterior cerebral circulation region detected by diffusion-weighted imaging (DWI). The preoperative and postoperative rCBF results were statistically analyzed. RESULTS: In the infarct group, there were significant increases in rCBF values of all nine brain regions at both PLD = 1.5 s and 2.5 s postoperatively compared to preoperatively. At PLD = 1.5 s, statistically significant differences in rCBF values between the preoperative and postoperative periods were found in the right thalamus, left cerebellum, midbrain, and pons regions (P < 0.05). At PLD = 2.5 s, statistically significant differences in rCBF values between the preoperative and postoperative periods were observed in the left occipital lobe, right cerebellum, midbrain, and pons regions (P < 0.05). When analyzing the rCBF values of the brain regions with recent infarcts in the infarct group, there was a significant increase in postoperative rCBF values compared to preoperative values (P < 0.05). After excluding the data from brain regions with recent infarcts, the CBF values in the remaining brain regions were also increased postoperatively, and some brain regions showed statistically significant differences in rCBF values between the preoperative and postoperative periods (P < 0.05). In the non-infarct group, there were no statistically significant differences in the preoperative and postoperative rCBF values in all brain regions at both PLD = 1.5 s and 2.5 s (P > 0.05). CONCLUSION: The application of 3D ASL technology shows significant value in assessing the surgical efficacy of vertebral-basilar artery stenting, especially in patients with acute posterior circulation infarction.

Posterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Bypass versus Occipital Artery-Posterior Inferior Cerebellar Artery Bypass for Treating Posterior Circulation Aneurysms: A Systematic Review and Comparative Meta-Analysis.

BACKGROUND: When traditional therapies are unsuitable, revascularization becomes essential for managing posterior inferior cerebellar artery (PICA) or vertebral artery aneurysms. Notably, the PICA-PICA bypass has emerged as a promising option, overshadowing the occipital artery-PICA (OA-PICA) bypass. The objective was to compare the safety and efficacy of OA-PICA and PICA-PICA bypasses. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we conducted a systematic review and meta-analysis to evaluate the safety and efficacy of OA-PICA and PICA-PICA bypasses for treating posterior circulation aneurysms. RESULTS: We analyzed 13 studies for the PICA-PICA bypass and 16 studies on the OA-PICA bypass, involving 84 and 110 patients, respectively. The median average follow-up for PICA-PICA bypass was 8 months (2-50.3 months), while for OA-PICA, it was 27.8 months (6-84 months). The patency rate for OA-PICA was 97% (95% confidence interval [CI]: 92%-100%) and 100% (95% CI: 95%-100%) for PICA-PICA. Complication rates were 29% (95% CI: 10%-47%) for OA-PICA and 12% (95% CI: 3%-21%) for PICA-PICA. Good clinical outcomes were observed in 71% (95% CI: 52%-90%) of OA-PICA patients and 87% (95% CI: 75%-100%) of PICA-PICA patients. Procedure-related mortality was 1% (95% CI: 0%-6%) for OA-PICA and 1% (95% CI: 0%-10%) for PICA-PICA. CONCLUSIONS: Both procedures have demonstrated promising results in efficacy and safety. PICA-PICA exhibits slightly better patency rates, better clinical outcomes, and fewer complications, but with a lack of substantial follow-up and a smaller sample size. The choice between these procedures should be based on the surgeon's expertise and the patient's anatomy.