Nondominant Vertebral Artery Research Articles

Mechanical Thrombectomy for Hyperacute Vertebrobasilar Ischemic Stroke via Nondominant Vertebral Artery : Clinical Experience and Considerations.

The dominant vertebral artery (VA) approach is primarily considered in mechanical thrombectomy (MT) for acute occlusion of the vertebrobasilar (VB) artery. As accessing the dominant artery is sometimes difficult, we present our experience treating acute VB stroke via a nondominant VA approach through a comparison with the dominant VA approach. Among 2,785 patients diagnosed with hyperacute ischemic stroke between January 2014 and December 2022, 50 patients with VB ischemic stroke underwent recanalization therapy through either dominant, nondominant, or bilateral VA approach. We evaluated patient characteristics and clinical course, highlighting the pros and cons of the access routes. The patients with hyperacute VB ischemic stroke were predominantly male (72%), with a mean age of 68.12 years and an initial National Institutes of Health Stroke Scale (NIHSS) score mean of 17.1. Large-artery atherosclerosis (LAA, 48%) and cardio-embolism (CE, 36%) were the main etiologic factors in the TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification. After thrombectomy, 45 (90%) cases had final modified thrombolysis in cerebral infarction (mTICI) score of 2b or higher. In summary, 41 patients were treated through the dominant VA, and 8 patients underwent the nondominant VA approach. However, there was no statistically significant difference in functional outcome or mortality between the two approaches. In MT for VB occlusions, nondominant VA approach may be an option in situations when the vessel is accessible, stable, or less risky, as recanalization can be achieved without rescue balloon angioplasty and/or stenting.

ANATOMICAL VARIATIONS OF THE VERTEBRAL ARTERY AND THEIR IMPLICATIONS

The Vertebral arteries correspond to a pair of vessels that originate from the superior branch of the 1st portion of the A. Subclavia. In general, they present general anatomical variations regarding the length and diameter of the lumen, with the left being larger than the right. More extreme variations, such as the absence of one of the arteries, due to agenesis or involution, are generally related to craniovertebral defects. The objective of this work was to evaluate the anatomical variations found in the vertebral arteries and to discuss their clinical implications. In the construction of this study, a descriptive research, of the RIL type, was carried out, fulfilling all the stages of development. The search resulted in 23 articles. After reading, the corpus was composed of 12 articles, whose potential content was dedicated to investigating the type of anatomical variation of the vertebral artery and its implications and harms in the health of the carriers. Symmetrical vertebral arteries are found in about 26% of individuals. Marked differences in the diameter of the arteries, called Vertebral Artery Dominance (VAD) result in a significant decrease in the blood flow velocity of the artery and an increase in the resistance index (RI). The incidence of infarction in the posterior region of the brain is significantly higher in individuals with VAD. Infarctions occurred more frequently on the side of the non-dominant vertebral artery, probably due to non-mixing of Aa blood. vertebral arteries within the A. basilar, which run separately and with a central zone where flow is absent, called the "dead spot". Changes in normal blood flow were tested to determine their correlations with sites of thrombosis and atherosclerosis in humans. The agenesis of some branches of A. vertebral is also identified as an important factor for the occurrence of strokes in the posterior region of the brain.

Endovascular treatment of acute basilar artery occlusion caused by vertebral artery stump syndrome: A clinical analysis of 37 cases

IntroductionAcute basilar artery occlusion (ABAO) caused by vertebral artery stump syndrome (VASS) has a low incidence and is always underestimated. Due to the occlusion of the origin of the vertebral artery (VA), it is often combined with basilar artery (BA) endovascular diseases or non-dominant contralateral vertebral artery, making the endovascular treatment (EVT) challenging to implement. ObjectiveThis article focuses on whether EVT and two interventional route options could bring clinical benefits to this group of patients: basilar artery thrombectomy through the occluded lateral vertebral artery and implementing revascularization of the occluded vertebral artery (dirty-road-path); thrombectomy through the non-occluded lateral vertebral artery (clean-road-path). MethodsWe collected six cases of acute embolic basilar artery occlusion (ABAO) due to VASS from January 2020 to December 2021 at our hospital and retrospectively analyzed 31 patients previously reported in the literature and applied statistical analysis to investigate the treatment options and clinical prognosis of these patients. ResultsThe clean-road-path surgical protocol was applied in 4 of 37 patients, the dirty-road-path protocol was applied in 29 patients, and 4 patients did not recanalized the basilar artery. By statistical analysis we found that successful recanalization of the basilar artery was clinically significant in reducing the modified Rankin Scale (mRS) scores in these patients, the statistical difference in the benefit of the two surgical protocols was negative. There was a significant positive correlation between preoperative National Institute of Health Stroke Scale (NIHSS) and postoperative 90-day mRS scores. ConclusionEndovascular treatment can benefit patients with ABAO due to VASS, and patients with higher preoperative NIHSS scores are more vulnerable to getting a poor prognosis. Comparison between the two endovascular options did not yield statistically significant results, but the dirty-road-path option may be superior to using the clean-road-path.

Management of posterior circulation tandem occlusions in acute ischemic stroke: Recanalize the dominant vertebral artery with priority.

To illustrate the characteristics of acute ostial vertebral artery (VA) and basilar artery (BA) tandem occlusions. The endovascular treatment strategy for ostial VA-BA tandem occlusion was reported. We conducted a retrospective analysis of patients with ostial VA-BA tandem occlusion who underwent endovascular treatment in our center between November 2018 and February 2022. We preferred to recanalize the dominant vertebral artery with priority. The imaging characteristics, treatment strategy, clinical outcomes, and complications were analyzed. In total, 9 patients with ostial VA-BA tandem occlusion were enrolled in this study. All the VA-BA tandem occlusion was caused by acute occlusion of the dominant VA. Endovascular revascularization was performed through the occluded dominant VA in 8 patients and was performed through contralateral non-dominant VA in 1 patient. Successful recanalization (mTICI 2b/3 grade) was achieved in all 9 patients, and 5 patients (55.5%) achieved functional independence with a mRS score of 0-2 at 90 days. In this case series, the occurrence of ostial VA-BA tandem occlusions was mainly caused by acute occlusion of the dominant VA. Endovascular revascularization of ostial VA-BA tandem occlusions through occluded dominant VA was feasible and recommended.

Low-dose three-dimensional CT angiography for the evaluation of posterolateral protrusion of the vertebral artery over the posterior arch of the atlas: a quantitative anatomical comparison study of the rotational and neutral positions

To investigate the changes in relevant anatomical parameters of posterolateral protrusion of the vertebral artery (VA) between head-neck rotational and neutral positions using low-dose three-dimensional computed tomography angiography (3D-CTA). Low-dose 3D-CTA images obtained for various craniocervical diseases in 36 non-dominant VA side patients with neutral, left and right head-neck rotational positions were evaluated. The relevant parameters from superior and inferior views, including external diameter (ED), internal diameter (ID), transverse diameter (TD), heights and diameters of posterolateral protrusion of the VA over the posterior arch of the atlas in the neutral and rotational positions, were recorded and compared. There was no significant differences in the rotational angle (left/right: 31.23±6.60/29.94±6.09°, p>0.05). There were no significant differences in heights and diameters of bilateral VA between rotational and neutral positions (all p>0.05). The contralateral ID, ED, and TD of the rotational positions were significantly shorter than those of the neutral position (all p<0.05), while there were no significant differences in the three ipsilateral diameters (all p>0.05). Posterolateral protrusion of the VA is not uncommon in the population, and surgeons should be aware of its presence, especially the increased possibility of injury to the VA caused by head-neck rotation, during the operation; thus, preoperative evaluation by low-dose 3D-CTA should be considered.

Endovascular parent artery coil occlusion for ruptured vertebral artery dissecting aneurysms

Background: The outcome of ruptured vertebral artery dissecting aneurysms (VADA) managed with endovascular coil occlusion technique is reviewed. Method: This is a retrospective study of prospectively collected data of 25 cases with ruptured VADA managed by a standardized endovascular parent artery occlusion technique. All cases were treated with coil occlusion of the dilated segment with a short proximal segment of the involved non-dominant or co-dominant vertebral artery within 12 hours of admission. All cases were done under general anesthesia with no anticoagulation. Outcome was assessed clinically with modified Rankin score as well as follow up MRI at 6 months. Results: There were a total of 25 cases, 10 female and 15 males. Age range 18 to 70, mean age 41. Twenty cases (80%) were WFNS grade 1 to 3. Five cases were grade 4 to 5. Treatment complication of cerebellar embolic infarct occurred in one case (4%). There was no hemorrhagic complication post treatment. 16 cases required ventriculoperitoneal shunting. Outcome was good with modified Rankin score of 0 to 2 in 20 cases (80%). There were 5 poor outcomes including one death (4%) due to the primary effect of subarachnoid hemorrhage in a case presenting with WFNS grade 5. All cases with WFNS grade 1 to 3 at presentation obtained good outcome. In all 24 cases who survived, follow up MRI showed that all aneurysms remained occluded at 6 months. Conclusion: Endovascular parent artery coil occlusion is effective and durable for ruptured VADA.

Total autogenous revascularization of an innominate artery occlusive disease

Total autogenous revascularization of an innominate artery occlusive disease

Endovascular Treatment of Intracranial Vertebral Artery Dissection.

Intracranial vertebral artery dissection (VAD) is the most common arterial dissection in intracranial arteries. Some types of VAD can heal spontaneously after reconstitution of the vessel lumen with excellent prognosis, whereas others can progress to stroke that needs treatment. Recently, endovascular treatment (EVT) has emerged and is suggested as a treatment option for VADs due to perceived low rates of procedure-related morbidity with good efficacy. In the last decade, we have accumulated our strategies to treat those VADs. Here, we try to share our experiences about VADs, including indications and methods of treatment of VADs using EVT. We perform EVT for ruptured VADs presenting with SAH and some of unruptured VADs such as VAD with recurrent or progressive ischemia, dissecting aneurysm larger than 7 mm or with mass effect, early ugly change of VADs in shape and size during follow-up period, involving the basilar artery (BA) and bilateral VADs. We present how we have done in our real practice for the last decade for treating VADs by EVT rather than reviewing and organizing so-far-published literature. We tended to occlude the rupture point by vertebral artery (VA) occlusion in non-dominant VA or stent-assisted coiling in dominant VA for ruptured VADs. We tended to reconstruct original hemodynamics using various stents for unruptured VADs. To decide what to treat and how to treat are very complicated for VADs. However, we believe that EVT is the current mainstay for treating VADs. Each technique of EVT should be determined on a case-by-case basis at the discretion of endovascular neurosurgeons and/or interventional neuroradiologists according to presenting symptoms, hemodynamic status, including sufficiency of the collateral supply and anatomic features of the vertebrobasilar artery as well as the posterior inferior cerebellar artery, anterior spinal artery, and medullary perforators.

Change in basilar artery length and bending according to aging and vertebral artery dominance: A longitudinal study

This study aimed to investigate the basilar artery (BA) geometric changes in a longitudinal study. 154 subjects with normal vertebrobasilar arterial systems on magnetic resonance angiography were assigned into two groups: 1) non-dominant vertebral artery (VA) and 2) VA dominance. We defined the dominant VA as either that the VA is 3 millimeters larger in diameter or the VA is connected to BA in a more straight angle. BA imaging was segmented to obtain BA bending length (BABL) and BA length (BAL). A mixed model ANOVA was conducted to investigate the impact of aging and VA dominance on the change of BABL and BAL after 123.6 ± 16.2 months. There was a significant main effect of VA dominance on the change of BABL after about 10 years, F (1,152) = 39.78, p < 0.01. On the other hand, there was a significant main effect of aging on the change of BAL during the same period of time, F (1,152) = 6.64, p = 0.01. Most subjects had an opposite directional relationship between the dominant VA and BA bending (71.3%; p < 0.01). Our study supported the hypothesis that the bending of the BA depends on the dominance of the VA, whereas the increased length of the BA depends on aging.

Prevalence of Anatomical Variants of the Circle of Willis

The Circle of Willis is an anastomotic structure that connects the anterior and posterior arterial networks that supply blood to the brain. It functions to maintain adequate blood supply to the brain in the event of obstruction due to injury or disease. Although it is well‐known that variants in the “textbook” structure of the Circle of Willis are common, previous studies characterizing the CoW have been limited by small sample sizes and, in some cases, reliance on cadaveric tissue in which preservation of delicate CoW structures is challenging. These shortfalls have made investigating the relationships between variants and neurological pathology difficult. Therefore, the purpose of the present study was to characterize the CoW in a large sample of living subjects to determine the prevalence of CoW variants and to identify relationships between variants and pathology. After approval for this study was obtained from the AdventHealth IRB, computed tomography angiography (CTA) scans of 1,494 cases were assessed for CoW variants and all CoW vessels measured. Inclusion criteria included patients aged 18–89 that received CTA imaging through AdventHealth Radiology between 11/15/12 and 11/14/17. One examiner assessed all CTA images via imaging software (Impax) for variants. Six other investigators measured each of the CoW vessels on the selected cases. Patient demographic information was collected via AdventHealth's medical record system. Our results indicate that CoW variants were present in 47.99% of the subjects. Of the cases with variants, 8.93% possessed symmetrical bilateral variations and 39.05% possessed multiple variants. The most commonly occurring variant was a non‐dominant vertebral artery at 17.27%. Of the non‐diminutive variants, meaning there were additions to or subtractions from the standard CoW architecture, the most commonly occurring variant was fetal origin posterior cerebral artery at 12.38%. Our results suggest that anatomical variants found in the Circle of Willis occur in just over under half of the population. Future analyses will characterize vessel diameters for the cases under study and relationships of each of the variants to neurological pathology. This study demonstrates the need for further investigation into the nature of altered CoW circulation patterns, how CoW variants may relate to brain function and pathology, and whether diminutive variants can be altered by non‐invasive interventions.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Conservative Management of Unruptured Spontaneous Intracranial Vertebral Artery Dissection

The present study investigated the clinical and morphological characteristics of the vertebrobasilar artery associated with vascular healing in patients with unruptured spontaneous intracranial vertebral artery (VA) dissection (VAD). We retrospectively reviewed the data from 69 consecutive patients with a diagnosis of unruptured VAD who were treated conservatively for ≥21 days from November 2003 to February 2018 at our institute. Univariate and multivariate analyses were performed to evaluate the clinical characteristics and morphological findings of VAD. Of the 69 patients, vascular normalization of VAD was observed in 26, including a significantly greater proportion of women and nonsmokers (P= 0.04 and P= 0.034, respectively). Patients with normalization of VAD had a significantly lower proportion of posteroinferior cerebellar artery involvement and a smaller vertebral-union-basilar angle of the nondissecting VA, smaller vertebral-union-vertebral angle, distal dissection from the VA union, and less basilar artery bending. Luminal irregularity/steno-occlusion of the VAD on the initial images exhibited vascular resolution/normalization in 25 patients (67.6%) on subsequent images. The morphology of VAD in the dominant or codominant VAs included fusiform/aneurysmal dilatation in 25 patients (78.1%). The morphology in the nondominant VA included luminal irregularity/steno-occlusion in 23 patients (62.2%). Spontaneous vascular normalization of unruptured spontaneous intracranial VAD might be associated with female sex, nonsmoking, no posteroinferior cerebellar artery involvement, a smaller vertebral-union-basilar angle and vertebral-union-vertebral angle, distal dissection from the VA union, less basilar artery bending, and luminal irregularity/steno-occlusion.

Posterior inferior cerebellar artery with an extradural origin from the V3 segment: higher incidence on the nondominant vertebral artery.

OBJECTIVE The posterior inferior cerebellar artery (PICA) and the vertebral artery (VA) often exhibit anatomical variations at the craniovertebral junction (CVJ). An example of this is the PICA originating extradurally from the V3 segment of the VA. To date, some cadaveric investigations have been reported, but the incidence and relationship of this variation to the VA and the atlas as observed on clinical imaging have not been discussed. This study evaluated the prevalence of PICAs originating from the V3 on CT scanning. Other variations of the atlas and VA were also analyzed. METHODS CT images from a series of 153 patients who underwent 3D CT angiography (CTA) were analyzed, and variations of the PICA, VA, and atlas were investigated. RESULTS A total of 142 patients (284 sides) were analyzed; 11 patients (7.2%) were excluded due to poor image quality. The most common VA variation was the PICA originating from V3 (9.5% of 284 sides), which was more frequently observed on the nondominant VA than the dominant VA (22.5% vs 6.25%, p = 0.0005). A VA with a PICA end was identified in 4 sides (1.4%), which is the same incidence as observed in the persistent first intersegmental VA (1.4%). VA fenestration was only found in 1 side (0.35%). Regarding the atlas, ponticulus posticus was observed in 24 sides (8.5%). There was no relationship between the incidence of ponticulus posticus and the variations of the VA. CONCLUSIONS A PICA originating from V3 was the most common VA variation at the CVJ and was more common on the nondominant VA. Three-dimensional CTA is useful for the evaluation of this variance. Surgeons should be mindful of this variation during operations.

Endovascular Treatment of Ruptured Vertebral Artery Dissecting Aneurysms

Background: Various endovascular treatment methods have been used to treat ruptured vertebral artery dissecting aneurysms (VADAs). However, the efficacy and long-term durability of the various endovascular techniques have remained unestablished. Objectives: The purpose of the present study is to report the therapeutic efficacy and long-term clinical and angiographic results of various endovascular treatment methods, and to evaluate the predictive factors of favorable outcomes. Patients and Methods: Between January 2010 and August 2014, 30 patients with ruptured VADAs were classified according to the dominancy of the affected vertebral artery (VA) and the involved major perforating vessels. Allotted endovascular therapy was performed for each of the ruptured VADA subtypes. Immediate angiographic and follow-up imaging results were retrospectively reviewed, and long-term clinical results were evaluated. Various clinical, angiographic, and procedural factors were evaluated to determine their associations with clinical outcomes. Results: Dissecting aneurysms involving the dominant VA were found in five patients. Of 25 aneurysms involving the non-dominant VA, 12 lesions showed involvement of the posterior inferior cerebellar artery (PICA), and one lesion’s origin was the anterior spinal artery. Stent-assisted coiling (SAC) was performed in seven patients, stent-only therapy (SOT) was conducted for six patients, and the remaining 17 patients were treated with internal coil trapping (ICT). Of the seven patients treated with SAC, five showed partial obliteration and four experienced recurrence. Two of the four patients with recurrence died. One patient with incomplete trapping for patency of the involved PICA experienced rebleeding. No recurrence was observed in six patients treated with SOT, or among 16 patients with ICT. The preoperative neurologic status (represented by the world federation of neurosurgical societies grading) and immediate post-treatment angiographic results were confirmed as significant predictive factors of clinical outcomes (P =0.018 for both variables). Conclusion: Incomplete obliteration of a ruptured VADA using SAC was associated with a higher recurrence rate and fatal clinical outcomes. ICT is a useful technique that completely eliminates the risk of rebleeding. However, under a limited set of conditions, SOT can be an effective alternative.

Investigation on in-stent recurrent stenosis after stenting of the extra-and intracranial artery in the elderly

Objective To investigate the distribution of in-stent recurrent stenosis (IRS) after balloon-angioplasty and stenting in elderly cerebral ischemic patient and its correlative factors. Methods Totally 158 elderly cerebral ischemic patients with extra-and/or intracranial artery stenosis were treated with 172 stents in our hospital. The inhibition of platelet function was assessed by using the thrombus elasticity chart system in perioperative period, and the anti-platelet agents were adjusted correspondingly. 150 patients were followed up by digital subtraction angiography (DSA) and the other 8 patients were followed up by CT angiography, during an average follow-up duration of 8.3 months. Results There were 11 (6.4%) IRS lesions, among which 10 lesions were at the vertebral artery origin and 1 lesion was at common carotid artery bifurcation. 23.8% of IRS happened after vertebral artery origin stenting, and all in-stent recurrent stenosis were in the origin of non-dominant vertebral artery, whose IRS rate was 66.7%. Conclusions IRS are more common found in vertebral artery origin than in other parts of vertebral artery and are more common found in non-dominant side than in dominant side. Key words: Stents; Angioplasty; Carotid stenosis; Vertebral artery

Comparison of Potential Risks between Intracranial and Extracranial Vertebral Artery Dissections

Background/Aims: To better understand potential risks for vertebral artery (VA) dissection (VAD), we compared intracranial and extracranial VADs. Methods: We analyzed consecutively admitted VAD patients over a 9-year period in whom VAD was confirmed by angiography. All patients were categorized as having intracranial or extracranial VAD, and demographic and radiological characteristics of VAD were compared. We used multivariate analysis to predict the risks for intracranial and extracranial VADs. Results: The study population (n = 74) had a mean age of 46.0 ± 10.3 years. VAD was more frequent in the nondominant VA (n = 49, 66.2%). Vertical nidus of VAD was more common in the intracranial segment (81.1%), and more particularly it was most frequently located within a 2-mm perimeter of the posterior inferior cerebellar artery (PICA) orifice (60.0%). Absence of traumatic history (OR 13.1, 95% CI 1.6-107.4; p = 0.016), history of hypertension (OR 14.1, 95% CI 1.1-184.6; p = 0.043) and aging (OR 1.1 per 1-year increase, 95% CI 1.0-1.2; p = 0.038) were independent predictors of intracranial VAD. Conclusion: As compared to extracranial VAD, intracranial VAD was particularly frequent and particularly vulnerable at the perimeters of the PICA and nondominant VA and was associated with an absent trauma history, hypertension and aging. Formation of VAD appeared to be different according to intracranial or extracranial involvement.

Bowhunter's Syndrome Diagnosed with Provocative Digital Subtraction Cerebral Angiography

Bowhunter's syndrome, also known as rotational occlusion of the vertebral artery, involves posterior circulation ischemia resulting from dynamic compromise of the dominant vertebral artery. This case highlights the importance of provocative digital subtraction angiography in making the diagnosis. A 41-year-old man presented for outpatient neurological evaluation for “lightheadedness” of several years' duration provoked by leftward head rotation. The only abnormality identified on initial magnetic resonance angiography was atresia of the nondominant left vertebral artery. Conventional digital subtraction angiography (DSA) followed by provocative DSA revealed development of a dynamic stenosis of the right vertebral artery involving the extraforaminal segment just superior to the C1 vertebra. Noncontrast computed tomography of the cervical spine confirmed ossification of the posterior right atlanto-occipital membrane leading to a near complete bony arcuate foramen. Following neurosurgical decompression, the patient demonstrated complete resolution of all neurologic symptoms. Bowhunter's syndrome is a unique clinical entity that must be considered in the evaluation of patients with symptoms of posterior circulation ischemia. Provocative DSA remains the preferred modality for definitive diagnosis.

Rotational vertebral artery syndrome due to compression of nondominant vertebral artery terminating in posterior inferior cerebellar artery

Rotational vertebral artery syndrome (RVAS) is characterized by recurrent attacks of paroxysmal vertigo, nystagmus, and ataxia induced by head rotation. We report on a patient who developed atypical RVAS due to compression of the vertebral artery (VA) terminating in the posterior inferior cerebellar artery (PICA). A 59-year-old man suffered from vertigo and nystagmus induced by leftward head rotation and oculography showed right beating horizontal-torsional and downbeat nystagmus. Cerebral angiography showed hypoplastic right VA terminating in PICA without connection to the basilar artery. The basilar artery received its flow from the left VA only and branched out both anterior inferior cerebellar arteries. Cerebral angiography revealed a complete occlusion of the right distal VA at the level of the C1-2 junction when the head was rotated to a leftward position. In contrast, the blood flow through the left vertebral and basilar arteries remained intact while turning the head to either side. The hemodynamic compromise observed in our patient with RVAS indicates that isolated vertigo and nystagmus may occur due to transient ischemia of the inferior cerebellum or lateral medulla.

Posterior transodontoid fixation: A new fixation (Kotil) technique

Anterior odontoid screw fixation or posterior C1-2 fusion techniques are routinely used in the treatment of Type II odontoid fractures, but these techniques may be inadequate in some types of odontoid fractures. In this new technique (Kotil technique), through a posterior bilateral approach, transarticular screw fixation was performed at the non-dominant vertebral artery (VA) side and posterior transodontoid fixation technique was performed at the dominant VA side. C1-2 complex fusion was aimed with unilateral transarticular fixation and odontoid fixation with posterior transodontoid screw fixation. Cervical spinal computed tomography (CT) of a 40-year-old male patient involved in a motor vehicle accident revealed an anteriorly dislocated Type II oblique dens fracture, not reducible by closed traction. Before the operation, the patient was found to have a dominant right VA with Doppler ultrasound. He was operated through a posterior approach. At first, transarticular screw fixation was performed at the non-dominant (left) side, and then fixation of the odontoid fracture was achieved by directing the contralateral screw (supplemental screw) medially and toward the apex. Cancellous autograft was scattered for fusion without the need for structural bone graft or wiring. Postoperative cervical spinal CT of the patient revealed that stabilization was maintained with transarticular screw fixation and reduction and fixation of the odontoid process was achieved completely by posterior transodontoid screw fixation. The patient is at the sixth month of follow-up and complete fusion has developed. With this new surgical technique, C1-2 fusion is maintained with transarticular screw fixation and odontoid process is fixed by concomitant contralateral posterior transodontoid screw (supplemental screw) fixation; thus, this technique both stabilizes the C1-2 complex and fixes the odontoid process and the corpus in atypical odontoid fractures, appearing as an alternative new technique among the previously defined C1-C2 fixation techniques in eligible cases.

Fenestrated vertebrobasilar junction aneurysm: diagnostic and therapeutic considerations

Vertebrobasilar junction (VBJ) aneurysms are uncommon and are often found in association with basilar artery (BA) fenestration. The complex anatomical environment of the VBJ, and the complicated geometry of the fenestration make clipping of these aneurysms difficult. Therefore, endovascular treatment of these aneurysms is now widely accepted. The authors describe the case of a 43-year-old woman with sickle cell anemia. She presented with subarachnoid hemorrhage. Digital subtraction angiography was performed and depicted multiple intracranial aneurysms. The patient had a left superior hypophysial artery aneurysm, a right superior cerebellar artery-posterior cerebral artery aneurysm, and a VBJ aneurysm associated with a fenestration of the BA. The VBJ aneurysm was not identified on the initial angiogram and was only revealed after 3D rotational angiography was performed. The 3D reconstruction was critical to the understanding of the complex geometry associated with the fenestrated BA. The VBJ was reconstructed using a combination endovascular technique. The dominant limb of the fenestration was stented and balloon-assisted coiling was performed, followed by sacrifice of the nondominant vertebral artery using coils and the embolic agent Onyx. Postoperative angiography demonstrated successful occlusion of the aneurysm with reconstruction of the VBJ. To the authors' knowledge, this is the first report of a fenestrated VBJ aneurysm treated with the combination of stenting, balloon remodeling, coiling, and vessel sacrifice. Three-dimensional angiography was critical in making the correct diagnosis of the source of the subarachnoid hemorrhage and with operative planning.

Craniovertebral junction malformation and rotational occlusion of the vertebral artery

An unusual case of rotational occlusion of a non-dominant vertebral artery (VA) is presented. This clinical syndrome is associated for the first time with a complex craniovertebral junction malformation. Rotational occlusion of the VA is usually asymptomatic, vertebro-basilar insufficiency has been rarely observed in cases of involvement of a dominant VA, and concomitant occlusion or hypoplasia of the contralateral artery. Diagnosis of rotational VA occlusion is based on haemodynamic demonstration of the effects of head rotation.The importance of the awareness of this syndrome is stressed.