Vertebral artery dissection as the underlying cause of ventral spinal epidural haematoma.

Spontaneous spine epidural haematoma is a rare occurrence, with an incidence of 0.1/100 000 inhabitants/year. The anterior location of the haematoma is very uncommon since the dural sac is firmly attached to the posterior longitudinal ligament. Vertebral artery dissection as its underlying cause is an exceptionally rare event, with only two documented cases.This article presents the case of young woman who arrived at the emergency room with a spinal ventral epidural haematoma extending from C2 to T10, caused by a non-traumatic dissecting aneurysm of the right vertebral artery at V2-V3 segment. Since the patient was tetraparetic, she underwent emergent laminectomy, and the vertebral artery dissection was subsequently treated endovascularly with stenting.Vertebral artery dissection with subsequent perivascular haemorrhage is a possible cause of spontaneous spine epidural haematoma, particularly when located ventrally in the cervical and/or high thoracic column. Hence the importance of a thorough investigation of the vertebral artery integrity.

Iatrogenic Vertebral Artery Dissection with Posterior Fossa and Lateral Medullary Stroke After Uncomplicated Cervical Nerve Ablation.

BACKGROUND: A cervical radiofrequency ablation is a procedure that can be performed to treat arthritis-related pain in the neck and upper back. There have been no large studies reporting complications after this procedure. We report a case of a 55-year-old woman with iatrogenic vertebral artery dissection of C3-C4 with segmental occlusion leading to a posterior fossa stroke and lateral medullary stroke after a high-grade cervical nerve ablation. CASE REPORT: A 55-year-old woman presented to the Emergency Department with vomiting, neck pain, temperature changes, dizziness, and dysarthria after undergoing C2-C3, C4-C5 nerve ablation 30 min prior to arrival. The patient was found to have a vertebral artery dissection with posterior fossa and lateral medullary stroke. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Vertebral artery dissection and subsequent stroke should be considered with recent cervical facet joint injections, such as intra-articular facet joint injections, medial branch blocks, or medial branch radiofrequency nerve ablation. The case we report shows devastating outcomes that can result from what many consider a relatively simple procedure.

Spontaneous intracranial vertebral artery dissections presenting with subarachnoid hemorrhage.

BACKGROUND: Vertebral artery dissection (VAD) is an infrequent source of subarachnoid hemorrhage (SAH), with a high mortality rate, primarily due to the risk of rebleeding both before and after medical intervention. This paper provides a comprehensive analysis of the anatomy, pathophysiology, clinical presentation, treatment strategies, and outcomes of intracranial vertebral artery dissections that result in subarachnoid hemorrhage. METHODS: Comprehensive five-year literature review (2018-2022) and a retrospective analysis of patient records from our institution between 2016 and 2022. We included studies with a minimum of 5 patients. RESULTS: The study incorporated ten series from the literature and 22 cases from CHUM. Key anatomical factors increasing the risk of VAD include the vertebral artery's origin from the aortic arch, asymmetry of the vertebral artery, and its tortuosity. Patients may display specific collagen and genetic abnormalities. The occurrence of VAD appears to be more prevalent in men. Those with a ruptured intracranial VAD typically show prodromal symptoms and present with severe SAH. Rebleeding within the first 24 h is frequent. While standard imaging methods are usually adequate for VAD diagnosis, they may not provide detailed information about the perforator anatomy. Treatment approaches include both deconstructive and reconstructive methods. CONCLUSION: Ruptured VAD is a critical, life-threatening condition. Many patients have a poor neurological status at presentation, and rebleeding prior to treatment is a significant concern. Deconstructive techniques are most effective in preventing rebleeding, whereas the efficacy of reconstructive techniques needs more investigation.

Role of optical coherence tomography in pipeline embolization device for the treatment of vertebral-basilar artery dissecting aneurysms.

BACKGROUND: Vertebral-basilar artery dissecting aneurysms (VADAs) are an uncommon phenomenon in all fields of cerebrovascular disease. The flow diverter (FD) can be used as an endoluminal reconstruction device that promotes neointima formation at the aneurysmal neck and preserves the parent artery. To date, imaging examinations such as CT angiography, MR angiography, and DSA are the main methods used to evaluate the vasculature of patients. However, none of these imaging methods can reveal the situation of neointima formation, which is of great importance in evaluating occlusion of VADAs, especially those treated with a FD. METHODS: Three patients were included in the study from August 2018 to January 2019. All patients underwent preprocedural, postprocedural, and follow-up evaluations with high resolution MRI, DSA, and optical coherence tomography (OCT), as well as the formation of intima on the surface of the scaffold at the 6 month follow-up. RESULTS: Preprocedural, postoperative, and follow-up high resolution MRI, DSA, and OCT of all three cases successfully evaluated occlusion of the VADAs and occurrence of in stent stenosis from different views of intravascular angiography and neointima formation. CONCLUSIONS: OCT was feasible and useful to further evaluate VADAs treated with FD from a near pathological perspective, which may contribute toward guiding the duration of antiplatelet medication and early intervention of in stent stenosis.

Flow diverters versus stent-assisted coiling in unruptured intracranial vertebral artery dissecting aneurysms.

OBJECTIVE: Flow diverters (FDs) have been used in unruptured intracranial vertebral artery dissecting aneurysms (IVADAs) with seemingly more favorable outcomes compared with stent-assisted coiling (SAC). However, the benefits of FDs over SAC in unruptured IVADAs need further evaluation. METHODS: This was a propensity score-matched, retrospective cohort study. Consecutive patients with unruptured IVADAs treated with FDs or SAC at the authors' hospital between January 2016 and December 2020 were reviewed. Propensity score matching at 1:1 was based on age, significant stenosis adjacent to aneurysmal dilatation, maximum diameter, and posterior inferior cerebellar artery involvement. Periprocedural cerebrovascular complications and angiographic and clinical outcomes were compared between the two matched groups. RESULTS: A total of 124 unruptured IVADAs in 123 patients (median age 53 [interquartile range 47-59] years; 101 men) were included. The FD and SAC groups included 65 and 59 IVADAs, respectively. Propensity score matching resulted in 47 matched pairs. The rates of immediate complete occlusion were significantly lower in the matched FD group than in the matched SAC group (6.4% vs 68.1%, p < 0.001). The rates of periprocedural cerebrovascular complications were comparable between the two matched groups (6.4% vs 6.4%, p > 0.99). At last follow-up, the rates of complete occlusion (89.4% vs 80.9%, p = 0.39) and favorable clinical outcomes (100.0% vs 97.9%, p > 0.99) were comparable, whereas the rate of recanalization was significantly lower in the matched FD group than in the matched SAC group (0.0% vs 12.8%, p = 0.03). Although the difference between the rates of in-stent stenosis was not statistically significant (17.0% vs 6.4%, p = 0.18), the difference in the effect measures was considerable. CONCLUSIONS: In unruptured IVADAs and compared with SAC, FDs provide comparable rates of periprocedural cerebrovascular complications, favorable clinical outcomes, and follow-up complete occlusion, lower rates of immediate complete occlusion and follow-up recanalization, and likely higher rates of in-stent stenosis.

Bypass Surgery for Vertebral Artery and Posterior Inferior Cerebellar Artery Fusiform Aneurysms: Surgical Technique and Key Lessons.

Fusiform vertebral artery (VA) aneurysms are challenging to treat due to their pathophysiology, morphology, and anatomic location.1,2 Endovascular treatments are considered to be a widely adopted safe option for this pathology.1 Open microsurgical treatment is considered for complex anatomy, important branch involvement, poor collateral flow, or failed endovascular therapy.3-7 This report aims to show the flow-replacement strategy and bypass technique for a VA aneurysm with complex anatomy and branch involvement. A 24-year-old man presented to our clinic with a bilateral fusiform VA aneurysm discovered during workup of progressive headaches. Further investigation revealed that the left-side aneurysm was mostly thrombosed and the posterior inferior cerebellar artery arose from the aneurysm dome with a fusiform enlargement within a few millimeters from the branching point. After evaluating all management options, the patient decided on surgical treatment of the left VA aneurysm. We performed an occipital artery to posterior inferior cerebellar artery end-to-side anastomosis distal to the fusiform enlargement, followed by trapping of the aneurysm and dome resection (Video 1). Antegrade flow to the distal VA was reestablished using a radial artery interposition graft, thus preventing any flow alterations that may cause growth or rupture of the contralateral aneurysm caused by increased hemodynamic stress if the ipsilateral VA flow is not preserved.8 After in-hospital physical rehabilitation, the patient was discharged with a modified Rankin Scale score of 1. The contralateral aneurysm is managed with serial imaging and treatment will ensue if there is clinical-radiologic evolution. The patient consented to the procedure and publication of his image.

Efficacy and predicting factors of multimodal treatment for ruptured intracranial vertebral artery dissecting aneurysms.

We aimed to investigate the efficacy of our multimodal strategies and propose a treatment algorithm for ruptured vertebral artery dissecting aneurysms (VADAs). This study included 41 patients treated at a single institution between 2015 and 2022. The treatment modalities were justified based on the collateral circulation and aneurysm location related to the posterior inferior cerebellar artery (PICA). Treatment outcomes and complications of each treatment group were analyzed. The association between the collateral blood flow and the postoperative vertebrobasilar ischemia (VBI) was also investigated. There were 17 post-PICA, 10 PICA-involved, 7 pre-PICA, and 7 non-PICA types. Reconstruction techniques included flow diversion devices (n = 11) and stent-assisted coiling (n = 3). Deconstruction techniques included coil trapping (n=17) and microsurgical parent artery occlusion with (n = 8) or without PICA revascularization (n = 2). Five (18.5%) of the deconstruction group had postoperative VBI. Overall favorable outcomes in both groups were observed in 70.7% of patients with a mean follow-up time of 21.5 months. Poor World Federation of Neurosurgical Societies grade (IV-V) was identified as a predictor of unfavorable outcomes (p = 0.003). In addition, the VA4/BA4 ratio > 0.22, the presence of collateral blood flow from the posterior communicating artery (PcomA), and a contralateral VA diameter > 2.5 mm were associated with a lower risk of postoperative VBI. In summary, the proposed strategic treatment in this study is pragmatic, yielding satisfactory results where a deconstructive technique should be used with caution, particularly when there is a flow mismatch or the absence of collateral PcomA in the vertebrobasilar circulation.

Occipital artery-to-PICA bypass: how I do it.

BACKGROUND: Posterior inferior cerebellar artery (PICA) aneurysms are uncommon, and their management is challenging because of the complex angioarchitecture of the PICA and the frequently nonsaccular aneurysm presentation. Endovascular therapy may not be feasible. METHODS: We describe our technique of clip trapping with occipital artery (OA)-to-PICA bypass to treat a PICA aneurysm. Because the aneurysm affected the ipsilateral, dominant PICA, an OA-PICA bypass was chosen to ensure adequate flow and reduce risk to the contralateral PICA supply. CONCLUSION: The OA-PICA anastomosis is a safe and effective method to successfully achieve flow preservation with bypass reconstruction and aneurysm trapping.

Clinical and Radiological Outcomes of Vertebral Artery Dissecting Aneurysms Treated with Endovascular Treatments: A 12-year Single-Center Experience.

OBJECTIVE: We aimed to compare the clinical and radiological outcomes of vertebral artery dissecting aneurysms (VADAs) stratified using different endovascular treatment methods. METHODS: We retrospectively reviewed 116 patients with VADAs treated at a single tertiary institute between September 2008 and December 2020. We analyzed and compared the clinical and radiological parameters according to different treatment methods. RESULTS: In total, 127 endovascular procedures were performed in 116 patients. We initially treated 46 patients with parent artery occlusion, 9 with coil embolization without stent, 43 with single stent with or without coil, 16 with multiple stents with or without coils, and 13 with flow-diverting stent. At the last follow-up (mean 37.8 ± 30.9 months), the complete occlusion rate (85.7%) was higher in the multiple-stent group than in the groups that received other reconstructive treatment methods. Moreover, the recurrence (0%) and retreatment (0%) rates were significantly lower in the multiple stent group (P < 0.001). The coil embolization-only group showed the highest recurrence (n = 5, 62.5%) and incomplete occlusion (n = 1, 12.5%) rates. The single-stent group showed higher recurrence (n = 9, 22.5%) and retreatment (n = 3, 7%) rates. Multivariate logistic regression analyses showed that coil embolization without stent placement (odds ratio = 172.76, 95% confidence interval = 6.83-4366.85; P = 0.002) was significantly associated with recurrence. At the last follow-up (mean, 42.1 ± 37.7 months), we achieved favorable clinical outcomes (modified Rankin Scale ≤2) in 106 of 127 patients. CONCLUSION: When treating VADAs, multiple stent placements may play a key role in achieving favorable long-term radiological outcomes.

Bow Hunter's syndrome combined with ipsilateral vertebral artery dissection/pseudoaneurysm: case study and literature review.

BACKGROUND: Bow hunter's syndrome (BHS), also known as rotational vertebral artery occlusion syndrome, is rare. Occasionally, it combines with dissection/pseudoaneurysm of the ipsilateral VA. METHODS: We report a case of BHS combined with ipsilateral VA dissection/pseudoaneurysm and review eight similar cases reported in the literature. Their aetiology, clinical and imaging features, treatment, and prognosis were analysed. RESULTS: Nine patients (seven male, two female; average age 22.0 ± 4.5 years) were enrolled. Visual symptoms comprised the most common clinical finding (66.7%, 7/9). Clinical symptoms were not related to neck rotation in seven patients (77.8%). Eight patients (88.9%) had multiple, scattered, new and old infarctions of the posterior circulation revealed on computed tomography/magnetic resonance imaging (CT/MRI) scans. Dissection/pseudoaneurysm was found in the ipsilateral VA - usually subtle and localised in the atlas, axis, and occipital bone - in all nine patients. Seven patients (66.7%) had special causes for the syndrome (i.e. congenital bone dysplasia). Altogether, 87.5% (7/8) experienced recurrence with cerebral infarction after antithrombotic therapy alone. Aetiologically targeted treatment, including surgical decompression or vertebral fixation, was performed in seven patients (77.8%). CONCLUSION: Young patients presenting with cryptogenic stroke in the posterior circulation and localised, subtle dissection/pseudoaneurysm of the ipsilateral VA around the atlanto-axial joint should undergo carotid ultrasonography with a neck rotation test or dynamic CT angiography/MR angiography/digital subtraction angiography, if necessary, to rule out/diagnose BHS.

Clinical characteristics, endovascular choices, and surgical outcomes of intracranial vertebral artery dissecting aneurysms: a consecutive series of 196 patients.

OBJECTIVE: The authors aimed to evaluate the clinical features, endovascular strategy selection, and outcomes of vertebral artery (VA) dissecting aneurysms (VADAs) near the origin of the posterior inferior cerebellar artery (PICA). METHODS: Clinical data were obtained from 196 patients with 202 VADAs who had been surgically treated at the authors' hospital between 2005 and 2021. The patients' medical records, imaging data, and follow-up outcomes were retrospectively analyzed. RESULTS: All 196 patients (148 male, 48 female; mean age 53 years) underwent endovascular therapy for VADA. The most common chief complaints were headache (56.6%), dizziness (40.8%), and other occasional symptoms (18.4%). Twenty-six patients experienced posterior circulation ischemia, and 25 patients experienced subarachnoid hemorrhage (SAH). On DSA images, 37 aneurysms were found in the dominant VA, and 165 aneurysms were found on the nondominant side. Eighty-eight VADAs had stenosis. Regarding the VADA location, there were 59 distal, 51 proximal, 23 ventral, 64 PICA, and 5 obliteration types. Single-stent implantation (10.9%), overlapping stent implantation (23.8%), flow diverter (FD) implantation (11.9%), single stent-assisted coil (SAC) embolization (31.7%), overlapping SAC embolization (12.9%), parent artery occlusion (PAO) (8.4%), and FD-assisted coil embolization (0.5%) were chosen. The follow-up rate was 82.7%. The modified Rankin Scale (mRS) score was 0.5 ± 1.1. Ninety-six patients underwent DSA. The complete occlusion rates were 100%, 81.4%, 56.7%, and 76.5% in the PAO group, SAC reconstruction group, stent implantation group, and FD implantation group, respectively. CONCLUSIONS: Young patients showed a higher probability of SAH, and elderly patients showed a higher probability of posterior circulation infarction. The surgical plan selection should be based on the SAH history, VA dominant side, and PICA origin location.

Computational fluid dynamics (CFD) analysis in a ruptured vertebral artery dissecting aneurysm implanted by Pipeline when recurrent after LVIS-assisted coiling treatment: Case report and review of the literatures.

BACKGROUNDS: Hemodynamics plays an important role in the natural history of the process of rupture and recurrence of intracranial aneurysms. This study aimed to investigate the role of hemodynamics for recurrence in a vertebral artery dissecting aneurysm (VADA). METHODS: A patient with a ruptured VADA firstly treated by low-profile visualized intraluminal support (LVIS)-assisted coiling, and was implanted with a Pipeline Embolization Device (PED) after aneurysm recurrence. Finite element analysis and computational fluid dynamics simulations were conducted in 6 serial imaging procedures, and the calculated hemodynamics was correlated with aneurysm recurrence. RESULTS: Wall shear stress (WSS) was not effectively suppressed, resulting in aneurysm recurrence with initial entry tear to occur above the protuberance after 7 months of LVIS stent-assisted coiling. With the implantation of PED, WSS, inflow stream and velocity at the aneurysm neck significantly decreased. During the 3-month follow-up after PED deployment, there was significant shrinkage of the sac and the blood flow in the sac was reduced considerably. The 27-month follow-up after PED deployment indicated the aneurysm was stable. CONCLUSIONS: The present case study suggests that insufficient suppression of high WSS and high inflow velocity at the neck of the parent artery, especially near the posterior inferior cerebellar artery, might be associated with aneurysm recurrence.

Application of double-stent assisted coil embolization in intracranial vertebral artery dissecting aneurysms with mass effect.

BACKGROUND: Unruptured intracranial vertebral artery dissecting aneurysms (IVADAs) with mass effect have an extremely poor natural course, and treatment of these aneurysms remains a challenge for endovascular and surgical strategies. The aim of this study was to analyze the role of double-stent-assisted coil embolization in preventing rupture and bleeding of intracranial vertebral artery dissecting aneurysm with brainstem compression by reducing mass effect and preventing the recurrence of the aneurysm. METHODS: A total of 25 patients (mean age, 56.04±13.0 years) with unruptured IVADAs with mass effect received dual-stent-assisted coil embolization. The baseline characteristics, the change of aneurysm size on MR, the rate of retreatment, and the improvement rate of clinical symptoms and signs were analyzed retrospectively. RESULTS: All patients completed the surgical procedures successfully. No aneurysm bleeding or perforating artery occlusion occurred during the perioperative and follow-up periods. The initial maximum diameter of the aneurysm on MR was 17.5±3.6 mm. One year after treatment, the maximum diameter of the aneurysm on MR was 15.8±4.9 mm. The reduction rate of the maximum diameter of the aneurysm was 10.7±12.7%. The change of the maximum diameter before and after treatment of aneurysm was statistically significant (P<0.001). In terms of the improvement rate of clinical symptoms, 15 cases were completely improved (60.0%), 6 cases were partially improved (24.0%), and the total clinical improvement rate was 84%. Four cases (16.0%) showed no improvement or even had aggravation of clinical symptoms. In 5 cases (20.0%), aneurysms recurred. Among 4 cases involving posterior inferior cerebellar artery origin, 3 cases had the recurrence (75%). 5 recurred cases were treated with single-stent-assisted coil embolization. No residual aneurysm and recurrence were found on the follow-up angiography. CONCLUSIONS: The double-stent-assisted coil embolization procedure is very safe and reliable. It can effectively prevent the aneurysm from continuing to grow and rupture and thereby reduce the clinical symptoms caused by the mass effect.

Comparison of Parent Artery Occlusion and Stent-Assisted Treatments in Ruptured Vertebral Artery Dissecting Aneurysms.

OBJECTIVE: To assess clinical outcomes of ruptured vertebral artery dissecting aneurysms, focusing on comparing parent artery occlusion (PAO) with stent-assisted treatments, and to identify risk factors for unfavorable outcomes and postprocedural complications. METHODS: This retrospective review included 36 ruptured vertebral artery dissecting aneurysms treated between February 2009 and April 2020. Treatment modalities included PAO without stent and stent-assisted treatments. Stent-assisted treatments included PAO with posterior inferior cerebellar artery (PICA) stenting and stent-assisted coiling. Univariate and multivariate analyses were conducted to evaluate risk factors for unfavorable outcomes and postprocedural complications. RESULTS: Patients were treated with PAO only (24, 66.7%), PAO with PICA stenting (4, 11.1%), and PAO with stent-assisted coiling (8, 22.2%). There were only fusiform aneurysms with PICA involvement in the PAO with PICA stenting group. In the stent-assisted coiling group, 4 aneurysms incorporated PICA, and 4 aneurysms involved dominant vertebral artery. Old age (odds ratio [OR] = 1.25, 95% confidence interval [CI] = 1.01-1.56, P = 0.044) and poor Hunt-Hess grade (OR = 537.99, 95% CI = 6.73-42994.1, P = 0.005) were significantly associated with unfavorable clinical outcomes after a mean follow-up of 37.5 ± 32.8 months. Fusiform dilatation shape (OR = 15.97, 95% CI = 1.52-167.38, P = 0.021) and PICA involvement (OR = 13.71, 95% CI = 1.29-145.89, P = 0.030) were independent risk factors for ischemic complications. CONCLUSIONS: Unfavorable clinical outcomes were significantly related to old age and poor Hunt-Hess grade. There were no significant differences between treatment groups in clinical outcomes or ischemic complications. Stent-assisted treatments might be effective and safe methods for ruptured vertebral artery dissecting aneurysms.

Symptomatic ischemic complications following endovascular treatment of vertebral artery dissecting aneurysms.

PURPOSE: The aim of this study is to investigate the clinical and radiological features related to the symptomatic ischemic complications of vertebral artery dissecting aneurysm (VADA) following endovascular treatment (EVT). METHODS: The clinical and radiological features of 127 VADAs, which were treated in a single tertiary institute between September 2008 and December 2020, were retrospectively reviewed. We defined a thrombosed aneurysm as being one which the thrombus was in the aneurysm in magnetic resonance imaging (MRI). Symptomatic ischemic complication was defined as a case in which acute infarction was confirmed on diffusion weighted image after EVT with associated clinical symptoms. Univariate and multivariate analyses were executed to demonstrate the associations between symptomatic ischemic complication and characteristics of VADA. RESULTS: The rate of symptomatic ischemic complication was 13.4% (17 of 127). The thrombosed aneurysms were observed in 24.4% (31 of 127) and posterior inferior cerebellar artery (PICA) involvement was shown in 38.6% (49 of 127). Multivariate logistic regression analysis demonstrated that thrombosed aneurysms (odds ratio [OR] = 8.54, 95% confidence interval [CI] 1.98-36.87, p = 0.004) and PICA involvement (OR = 4.26, 95% CI 1.03-17.68, p = 0.046) were significantly associated with symptomatic ischemic complications following EVT. CONCLUSION: This study showed that the VADAs with intra-aneurysmal thrombose and PICA involvement may be independent risk factors for symptomatic ischemic complications following EVT. Therefore, when the thrombosed VADAs with PICA involvement are observed, practitioners may consider close postoperative monitoring for early detection of ischemic complications.

Treatment for Hemifacial Spasm Associated with a Dissecting Vertebral Artery Aneurysm Requiring Microvascular Decompression in Addition to Endovascular Trapping: A Case Report with Literature Review.

BACKGROUND: The treatment protocol for hemifacial spasm (HFS) associated with dissecting vertebral artery aneurysm (DVAA) has not been established. CASE DESCRIPTION: A-42-year-old man with left HFS underwent endovascular trapping for a DVAA that was identified on brain imaging. Although the dissecting segment was treated successfully, the HFS persisted for 3 months, and subsequently microvascular decompression (MVD) was needed. The posteroinferior cerebellar artery (PICA) was found to be interposed between the root exit zone of the facial nerve and DVAA during surgery. After pulling out the PICA, the HFS ceased immediately. CONCLUSION: HFS associated with DVAA should be considered carefully before formulating a treatment strategy. Moreover, the cause of pulsatile compression may not be visible on brain imaging, and MVD surgery may be indicated in such cases.

Occipital Artery -Posterior Inferior Cerebellar Artery Bypass Combined with Aneurysm Trapping for a Recurrent Ruptured Vertebral Artery-Posterior Inferior Cerebellar Artery Aneurysm: Two-Dimensional Operative Video.

Vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysm is challenging owing to its variable anatomy and interference of lower cranial nerves. A recurrent ruptured VA-PICA aneurysm was successfully treated by occipital (OA)-PICA bypass with aneurysm trapping (Video 1). Informed consent was obtained from the patient. A ruptured right VA aneurysm was found in a 47-year-old man and treated by endovascular treatment. Follow-up angiography at 1 month revealed aneurysm recurrence with migration of endovascular materials. The patient was placed in a park-bench position for the far-lateral approach. A J-shaped incision was used for craniotomy. A 1-piece myocutaneous flap was raised, and the OA was skeletonized in a distal-to-proximal fashion. After craniotomy, the VA-PICA aneurysm with endovascular material inside was located under the vagoaccessory triangle. The tonsillomedullary segment or P3 of the PICA was robust and long enough as the recipient candidate for anastomosis. A linear arteriotomy was performed on the recipient artery, and an end-to-side OA-PICA bypass was achieved. Occlusion of the aneurysm was achieved by placing permanent clips on the VA proximal and distal to the aneurysm and the PICA next to the aneurysm sac without occluding the perforator. The postoperative course was uneventful with bypass patency. We believe this case demonstrates the surgical tenet of OA-PICA bypass for VA-PICA aneurysm.

Pregnancy as a Subgroup in the Pathophysiologic Classification of Spinal Aneurysms.

BACKGROUND: Aneurysms of spinal arteries not associated with any known predisposing condition are referred to as isolated spinal aneurysms (SAs). In our series, an SA was found in 2 patients during the postpartum period. The goal of this study is to determine whether an occurrence of an SA may be related to puerperium. METHODS: In a retrospective analysis of our consecutive series of 10 cases of SAs from 2008 to 2020, we identified 2 cases of SAs during puerperium. Patients' charts and imaging were reviewed, for potential predisposing factors. RESULTS: In both cases, angiography showed fusiform aneurysms of the anterior SA with concomitant bilateral vertebral artery (VA) dissections. Serum vasculitis and inflammatory panel and genetic testing for collagen disorders were negative in both cases. Review of the literature showed that pregnancy is associated with an increased risk of arterial dissections in various locations and supports the hypothesis that hemodynamic and hormonal changes may play a role in the formation of SAs. CONCLUSIONS: Pregnancy and peripartum state may be a distinct cause of the formation of SAs, possibly as a result of increased hemodynamic stress and hormonal changes that may alter the arterial wall. It would be appropriate to add pregnancy as a subgroup in the classification of SAs. In our series, both cases were associated with bilateral VA dissections; it is possible that the bilateral VA stenosis may have contributed to the formation of the SAs. It is important to recognize this possibility when considering the occlusion of a dissected VA.