Segment Of Vertebral Artery Research Articles

A Case of Ipsilateral Hemiparesis in Lateral Medullary Infarction: As a Warning Sign of Acute Progression of Vertebral Artery Thrombosis

A 70-year-old man presented with acute dysarthria and dizziness. He denied any history of trauma or cervical manipulations within several weeks before symptom onset. We could make a presumptive diagnosis of left Wallenberg syndrome through the results of neurologic examination, which include left limb ataxia, alternating hyp(o)esthesia, spontaneous nystagmus to right side, and left side Honer’s syndrome. Initial diffusion weighted imaging performed at admission showed small and discrete high signal lesions in left lateral medulla, left cerebellar hemisphere, and bilateral occipital areas. Contrast enhanced MRA demonstrated a fi lling defect in long segment of distal left vertebral artery. On 4th days after symptom onset, the patient developed a severe form of ipsilateral hemiparesis. Follow-up brain MRI showed a downward extension of the initial ischemic lesion in upper medulla to upper cervical region. This case suggests that a severe form of ipsilateral hemiparesis may be complicated in the clinical setting of acute lateral medullary infarction with vertebral artery occlusion. (Korean J Stroke 2011;13:137-139)

In Vivo Retrieval of a Trapped Merci Embolectomy Device

This technical note describes a complication related to the use of the Merci embolectomy device not previously reported. The device can induce critical flow limitation within an accessed vessel because of a combination of vasospasm and anatomic conformational changes. Furthermore, this can limit the safe removal of the device from intracranial vasculature. We present a novel rescue technique that can be used to safely retrieve the entrapped Merci device without inciting localized vessel injury. A 51-year-old male with embolic occlusion of the distal basilar artery and dissection-related occlusion of the left cervical vertebral underwent mechanical thrombolysis. Flow-limiting vasospasm and/or anatomic conformational changes/ telescoping of the intracranial right vertebral artery segment was induced during deployment with subsequent entrapment of the device. Reclamation of the entrapped device was performed by initially removing the Merci microcatheter. The entrapped and fixated device was then resheathed into a 4F slip catheter within the intracranial vertebral artery. The Merci device and the slip catheter were then removed. Right vertebral and proximal basilar artery flow was reestablished after removal of the Merci device. Successful clot extraction was thereafter performed using a microsnare. In vitro assessment of the device has demonstrated its propensity to induce vasospasm. In vivo entrapment of the device has not been previously reported. Successful retrieval can be achieved if the Merci device becomes entrapped and fixated. This may be an important consideration as increased utilization of the device occurs.

A 10-year follow-up of extracranial–intracranial bypass for the treatment of bilateral giant internal carotid artery aneurysms in a patient with fibromuscular dysplasia: case report

Cervicocephalic fibromuscular dysplasia (FMD) is an idiopathic, non-inflammatory and non-atherosclerotic arteriopathy which usually affects small- and medium-sized cervical arteries distributed at the atlas and axis interspace. Few cervicocephalic FMD patients are associated with multiple intracranial aneurysms which may rupture or develop. So the authors describe a cervicocephalic FMD patient with a history of right oculomotor palsy in 2000. Angiography revealed bilateral internal carotid artery (ICA) aneurysms and a fusiform aneurysm in right vertebral artery. Typical "string-of-beads" phenomenon was observed in V2 segment of left vertebral artery. The right ICA giant aneurysm was treated by right ICA occlusion and superficial temporal artery (STA)-middle cerebral artery (MCA) bypass at that time. Five years later, the patient presented with paroxysmal weakness in right limbs. The subsequent angiography showed the enlargement of left ICA aneurysm. It was treated satisfactorily with left external carotid artery-saphenous vein-MCA bypass and left ICA ligation. During the long-term follow-up, the patient kept no neurological deficit and the angiography showed good patency of bilateral grafts and the lesions in bilateral vertebral arteries remained unchanged.

Vertebral artery–posterior inferior cerebellar artery bypass using a radial artery graft for hemorrhagic dissecting vertebral artery aneurysms: surgical technique and report of 2 cases

Endovascular occlusion of hemorrhagic dissecting aneurysms of the vertebral artery (VA) is not possible when the posterior inferior cerebellar artery (PICA) originates from the dissecting aneurysm or when the contralateral VA provides inadequate collateral blood flow to the distal basilar circulation. The authors introduce a VA-PICA bypass with radial artery interposition graft and aneurysm trapping as an alternative approach and describe 2 cases in which this bypass was used to treat hemorrhagic dissecting VA aneurysms. The VA-PICA bypass is performed via a standard far lateral approach. An end-to-side anastomosis between the radial artery graft and the PICA at the level of the caudal loop is performed first, and an end-to-side anastomosis is performed between the V(3) segment and the proximal end of the radial artery graft. A 56-year-old woman harbored a hemorrhagic dissecting VA aneurysm incorporating the origin of the PICA. Endovascular treatment failed, with aneurysm refilling on follow-up angiography. A 65-year-old man had a hemorrhagic dissecting VA aneurysm and a hypoplastic contralateral VA. Both patients were treated with the VA-PICA bypass and aneurysm trapping, with adequate filling of the PICA territory in the first patient and both the PICA territory and the basilar circulation in the second patient. Vertebral artery-PICA bypass with radial artery interposition graft and subsequent trapping of the dissected VA segment is an alternative to occipital artery-PICA and PICA-PICA bypass for the treatment of hemorrhagic dissecting VA aneurysms that are not suitable for endovascular occlusion.

Preliminary Report: Biomechanics of Vertebral Artery Segments C1-C6 During Cervical Spinal Manipulation

Objective The purpose of this study was to measure strains in the human vertebral artery (VA) within the cervical transverse foramina and report the first results on the mechanical loading of segments of the VA during spinal manipulation of the cervical spine. Methods Eight piezoelectric ultrasound crystals of 0.5-mm diameter were sutured into the lumen of the left and right VA of one cadaver. Four hundred–nanosecond ultrasound pulses were sent between the crystals to measure the instantaneous lengths of the VA segments (total segments n = 14) at a frequency of 200 Hz. Vertebral artery engineering strains were then calculated from the instantaneous lengths during cervical spinal range of motion testing, chiropractic cervical spinal manipulation adjustments, and vertebrobasilar insufficiency testing. Results The results of this study suggest complex and nonintuitive strain patterns of the VA within the cervical transverse foramina. Consistent (for 2 chiropractors) and repeatable (for 3 repeat measurements for each chiropractor) elongation and shortening of adjacent VA segments were observed simultaneously and could not be explained with a simple model of neck movement. We hypothesized that they were caused by variations in the location and stiffness of the VA fascial attachments to the vertebral foramina and by coupled movements of the cervical vertebrae. However, in agreement with previous work on VA strains proximal and distal to the cervical transverse foramina, strains for cervical spinal manipulations were consistently lower than those obtained for cervical rotation. Conclusions Although general conclusions should not be drawn from these preliminary results, the findings of this study suggest that textbook mechanics of the VA may not hold, that VA strains may not be predictable from neck movements alone, and that fascial connections within the transverse foramina and coupled vertebra movements may play a crucial role in VA mechanics during neck manipulation. Furthermore, the engineering strains during cervical spinal manipulations were lower than those obtained during range of motion testing, suggesting that neck manipulations impart stretches on the VA that are well within the normal physiologic range of neck motion.

Non-invasive evaluation of vertebral artery blood flow in cervical spondylosis with and without vertigo and association with degenerative changes

Cervical spondylosis is a common disease that results from degenerative changes of the cervical spine and vertigo may occur in this process. The aim of the present study was to assess the blood flow measurements of the vertebral artery (VA) using color Doppler ultrasonography (CDUS) in patients who have cervical spondylosis with and without vertigo. The study population included 101 patients with vertigo and spondylosis, 66 patients with spondylosis without vertigo, and 62 healthy controls. A bilateral decrease in the VA blood flow velocities were measured in patients with cervical spondylosis. A negative correlation was found between the stage of cervical degenerative changes and the flow velocities in patients with vertigo, while this relationship was not found in patients without vertigo. The CDUS evaluation of the pretransverse and transverse segments of VAs demonstrated significantly reduced flow velocities in patients with spondylosis. The degenerative changes in the cervical spine seem to be related to these velocity changes in the subgroup of patients who are also affected with vertigo. The pretransverse segment of the VA provides valuable measurements as well as transverse segment of the VA, and it can be used as an appropriate segment for CDUS examination in cervical spondylosis and associated vertigo.

Preliminary Personal Experiences With the Application of Near-Infrared Indocyanine Green Videoangiography in Extracranial Vertebral Artery Surgery

We evaluated the feasibility, usefulness, and limitations of near-infrared indocyanine green (ICG) videoangiography during procedures involving the extracranial vertebral artery (VA). Nine patients (2 women, 7 men; mean age, 55 years) were evaluated at 2 neurosurgical centers. Near-infrared ICG videoangiography was applied during transposition and rerouting of the first segment of VA (V1; n = 6) and during resection of neurinomas near the second (V2; n = 1) and third (V3; n = 2) segments of VA. Early after ICG injection, V1 fluoresced homogenously. The fluorescence of V2 and V3 varied. Without extrinsic compression, these segments appeared as noncontiguous hot spots because the VA runs freely in a periosteal sheath surrounded by a venous plexus that attenuates the fluorescent light. Hot spots corresponded to areas where the artery neared the surface. With extrinsic compression, VA enhanced homogenously because it was pushed against the periosteal layer. During the late phase, the V1 signal was attenuated, whereas the venous plexus surrounding V2 and V3 enhanced homogeneously, thereby masking the VA itself. Near-infrared ICG videoangiography helped to confirm VA patency during transposition and rerouting but was not helpful during VA exposure because the periosteal sheath must already be exposed to detect the VA or its surrounding plexus. After exposure, videoangiography can help to determine the position of the VA within its periosteal sheath. Videoangiography can be used to provide information about the patency of the VA and its location within the periosteal sheath to prevent injury during resection of tumor adherent to the periosteal sheath.

Time-resolved, contrast-enhanced 3D MR angiography in the subclavian steal effect

The subclavian steal effect indicates atherosclerotic disease of the supraaortic vessels but rarely causes cerebrovascular events in itself. Noninvasive imaging providing detailed anatomic as well as hemodynamic information would therefore be desirable. From a group of 25 consecutive patients referred for MR angiography, four with absent or highly attenuated signal in one of the vertebral arteries on 3D multislab time-of-flight MR angiography were selected to undergo 3D time-resolved contrast-enhanced MR angiography. The time-resolved 3D contrast series (source images and MIPs) were evaluated visually and by graphic analysis of time-intensity curves derived from the respective V1 and V3 segments of both vertebral arteries on the source images. In two cases with high-grade proximal left subclavian stenosis, time-resolved 3D ce-MRA was able to visualise retrograde contrast filling of the left VA. There was a marked delay in time-to-peak between the left and right V1 segments in one case and a shallower slope of enhancement in another. In the other two cases, there was complete or collateralised segmental occlusion of the VAs.

Stent-assistant angioplasty for treatment of cerebral artery stenosis

Objective To study the efficacy and safety of stent-assistant angioplasty (SAA) in the treatment of cerebral artery stenosis. Methods SAA was performed on 19 patients with cerebral artery stenosis, including 13 cases of stenosis at the initial segment of internal carotid (5 cases of transient ische mic attack and 8 cases of cerebral infarction) , and 6 cases of stenosis at the initial segment of vertebral artery (all exhibiting transient ischemic attack). Results Nineteen stents were all successfully implanted. Mean artery stenosis (AS) before surgery was 86% , whereas the remnant stenosis after operation was 10%. The significantly increased hemodynamics reverted to normal after operation immediately and sustained during the follow-up. NIHSS in patients with cerebral infarction was improved Significantly after surgery. Postoperative bradycardia and hypotension occurred in three patients with internal carotid stenosis and treated by medicine. Only one case receiving carotid artery stent exhibited symptom deteriorated slightly during follow-up of the 22th week. One patient with vertebral artery stenosis exhibited one time of transient ischemic attack at the 19th week after surgery. The remaining patients had no recurrence of symptom during the follow-up of 6 months. Conclusion SAA for treatment of cerebral artery stenosis was safe and effective. Key words: Cerebral artery stenosis; Stent; Angioplasty

FP06-MO-02 Economy class stroke in Hong Kong

interest artery include intracranial segment of internal carotid, intracranial segment of vertebral artery, basilar artery, middle cerebral artery. The technical success rate, average stenosis before and after treatment, major complications and clinical outcome were recorded. Conventional angiography was performed at 6 months after stenting to evaluate the patency of stent. Results: The average pretreatment stenosis was 80.6±12.1%. After Wingspan stent deployment, the average stenosis was 14.3±10.2%. The technical success rate was 100%. The rate of ipsilater stroke within 30 days and 6 months was 6.3% and 12.5%, respectively. The symptoms were significantly improved in 68.8% patients. Five patients underwent CT angiography, and in-stent stenosis was detected in one patient with 80% restenosis. Conclusion: Symptomatic intracranial artery stenosis can be treated with Wingspan stent with a high rate of technical success, acceptable safety and favorable clinic outcome.

Treatment of symptomatic intracranial atheromatous stenosis with the Gateway balloon and Wingspan stent system: short and medium term results

Objective To assess the safety, feasibility and short-mid term effectiveness of the Wingspan stent in the treatment of high-grade symptomatic intracranial atheromatous stenosis. Methods Sixty-three patients with symptomatic intracranial atheromatons stenosis (≥ 70%) were treated with the Gateway balloon-Wingspan stent system. The pre-and post-treatment improvement of symptoms, severity of stenosis, successful rate of treatment, complications were evaluated. Physician-reported follow-up in all 63 patients lasted an average period of 9. 3 months. The X2 test was used for statisties. Results Sixty-three lesions involved the intracranial internal carotid artery (n = 12), middle cerebral artery (n = 22), V4 segment vertebral artery (n = 15), basilar artery (n = 14). Sixty-two lesions were successfully treated with the deployment of the self-expanding Wingspan stent with residual stenosis ≤ 30%. One case failed because of intracranial hemorrhage during the operation. The successful rate of stenting is 98.0% (62/63). The mean stenosis was (82. 3 ± 9. 2) % before treatment, and it improved to (23.0 ± 11.2) % after stent placement. During the follow-up period, 1 patient died of postprocedural hyper-perfusion, one had ischemic stroke after procedure, one presented Homer syndrome at the 11th day, one had iachemic stroke at the 5th month after the procedure, while the other patients had significantly improved. The frequency of ≥50% restenosis on follow-up angiography or computed tomography was 10% (1/10). Conclusions Angioplasty and stenting for high-grade symptomatic intracranial artery stenosis with the Gateway-Wingspan stent system are safe and effective with high rate of technical success, but moderately high rate of residual stenosis and restenosis exist. With the improvement of operation skill and stent system, a better outcome in the future could be achieved. Key words: Vertebasilar insufficiency; Intracranial arteriosclerosis; Angioplasty; Stent

Three-dimensional CT study on the anatomy of vertebral artery at atlantoaxial and intracranial segment

The atlantoaxial and intracranial segments of vertebral artery (V(3-4)) are winding around their peripheral structures. Their panorama is not easy to be observed in surgery. CT angiography (CTA) shows some advantages in this aspect. So, the aim of this study is to reveal the three-dimensional (3D) anatomy related to V(3-4) and prepare ground for clinical diagnosis and treatment. Ninety-eight cases without the pathologies of V(3-4) were selected from the head-neck CTA examination. All the 3D images were formed with multiplanar reconstruction, volume rendering and volume rendering together with separating, fusing, opacifying and false-coloring. On the 3D images, the courses and branch of V(3-4) were observed and measured, as well as their peripheral venous vascular plexus (VVP). V(3-4) with typical five curves was found in 85 cases and with variations in 13. The left V(3-4) is larger than right (P < 0.05). The branch shown on the 3D image is the posterior inferior cerebellar artery at V(4), at most two on either side. VVP are at the back of the atlantoaxial joints and around the V(3), each on either side. There is no significant difference in size and shape between left and right (P > 0.05). The anatomy and variations of V(3-4) can be clearly and directly shown by 3DCTA. The understanding of vertebral artery and bony structures around there can provide anatomic basis for surgery and radiological diagnosis.

Simple identification of the third segment of the extracranial vertebral artery by extreme lateral inferior transcondylar-transtubercular exposure (ELITE)

The exposure of the third segment of the extracranial vertebral artery (V3) is an important step in the extreme lateral inferior transcondylar-transtubercular exposure (ELITE) approach. The muscular suboccipital triangle provides one of the landmarks to identify the V3 segment; however, identification of this triangle and dissection of the V3 segment is not always straightforward in the actual surgery. Blind dissection below the level of the foramen magnum can lead to vertebral artery injury. While the surgeon may be able to readily define the V3 segment of the vertebral artery by feeling its pulse, it is important to have a safe systematic approach to finding the V3 segment when the vessel is illusive. We propose a simple method to identify the V3 segment avoiding accidental injury of the vertebral artery. Sixteen cadaver heads (using both sides) were prepared by injecting red- or blue-coloured silicone into their arteries and veins, respectively. We performed an ELITE bilaterally on each cadaver head following four key bony landmarks. A postauricular lazy S-shaped skin incision was made centered just behind the mastoid tip. The posterior neck muscles were cut along the line of the skin incision behind the attachment of the sternocleidomastoid muscle to expose the occipital bone. All the incised muscles were reflected anteriorly as the ELITE is a dorsolateral approach. A suboccipital craniotomy was made exposing the posterior half of the sigmoid sinus up to the inferior retrosigmoid point (point A). The foramen magnum was opened after the craniotomy was completed. The dura on the foramen magnum was followed posteriorly in order to identify the occipital midline dural point (point B) that is identified by the bony ridge at the junction of the posterior fossa dura on the foramen magnum and the posterior most aspect of the spinal dura. The posterior tubercle of C1 (point C) was identified directly inferior to Point B. The posterior arch of C1 was followed anteriorly from the tubercle to find the "J-groove", which cradles the vertebral artery (point D). The V3 segment lies above this groove, covering the paravertebral venous plexus. We measured the distances between the landmarks introduced above after completion of the exposure. The distance between points A and B was 30.5 +/- 5.6 mm, points B-C was 10.4 +/- 2.3 mm, points C-D was 19.1 +/- 3.8 mm. The V3 segment was identified using the anatomical relationships described above in all heads. In no cadaver specimen was the artery injured. Identification of the V3 segment of the vertebral artery by systematically detecting the four anatomical points defined above is simple and much safer than a direct dissection below the foramen magnum.

Microsurgical anatomy of the third segment of vertebral artery

Objective To accumulate the morphological data of the third segment of vertebral artery and to provide the basis of microvascular anatomy for clinical treatment. Method Ten adult cadaver heads (20 sides)were used in the study. The morphology of the third segment of vertebral arteries was observed and their dimensions were measured with the aid of an operating microscope. Results The third segments of the vertebral arteries were tortuous. The external diameters of left vertebral arteries(4. 01 ±1.12)mm were larger than that of the right ones (3.45± 0. 32) mm. The length of the third segment of the vertebral artery was(50. 93 ±8. 23)ram. There was no significant anatomic variation. Conclusions The third segment of vertebral artery is tortuous to enable the movements of neck. The far-lateral approach is often used to expose the third segment of vertebral artery. The suboccipital triangle may be an anatomic marker for the third segment of vertebral artery. Key words: Vertebral artery; Anatomy; Suboccipital triangle

Intracranial vertebral artery dissection resulting in fatal subarachnoid hemorrhage: clinical and histopathological investigations from a medicolegal perspective

Subarachnoid hemorrhage (SAH) due to a ruptured intracranial vertebral artery (VA) dissection sometimes results in a sudden fatal outcome. The authors analyzed the relationship between clinical features and histopathological characteristics among fatal cases to establish valuable information for clinical diagnostics and prophylaxis. This study included 58 medicolegal autopsy cases of ruptured intracranial VA dissection among 553 fatal nontraumatic cases of SAH that occurred between January 2000 and December 2007. Their clinical features were obtained from autopsy records. Histopathological investigations were performed on cross-sections obtained from all 4-mm segments of whole bilateral intracranial VAs and prepared with H & E and elastica van Gieson staining. The autopsy cases included 47 males and 11 females, showing a marked predilection for males. The mean age was 46.8 +/- 7.7 years, with 78% of the patients in their 40s or 50s. Hypertension was the most frequently encountered history; it was found in 36% of cases from clinical history and in 55% of cases based on autopsy findings. Prodromal symptoms related to intracranial VA dissections were detected in 43% of patients. Headache or neck pain lasting hours to weeks was a frequent complaint. Of patients with prodromal symptoms, 44% had consulted doctors; however, in none of these was SAH or intracranial VA dissection diagnosed at a preventable stage. Autopsy revealed fusiform aneurysms with medial dissecting hematomas. Apart from ruptured intracranial VA dissection, previous intracranial VA dissection was detected in 25 cases (43%); among them, 10 showed previous dissection of the bilateral intracranial VAs. The incidence of prodromal symptoms (60%) among the patients with previous intracranial VA dissection was significantly higher than that (30%) among cases without previous dissection (chi-square test; p = 0.023). Most previous intracranial VA dissections formed a single lumen resembling nonspecific atherosclerotic lesions, with the exception of 3 cases (12%) with a double lumen. Intracranial VA dissection resulting in fatal SAH frequently affects middle-aged men with untreated hypertension. Related to the high frequency of prodromal symptoms, latent previous intracranial VA dissection was histopathologically detected. Furthermore, intracranial VA dissection tends to induce multiple lesions affecting both intracranial VAs recurrently. This suggests the importance of an awareness of sustained whole intracranial VA vulnerability for the prevention of recurrence. The incidence of prodromal symptoms was significantly higher among patients with previous intracranial VA dissections. Thus, earlier diagnosis of intracranial VA dissections at the unruptured stage is desirable for prophylaxis against fatal SAH.

Traumatic vertebral artery aneurysm following blunt suboccipital trauma

Traumatic vertebral artery (VA) injury has been neglected and mistaken to be innocuous. Herein, we present a rare case with a as subarachnoid hemorrhage (SAH) following blunt suboccipital trauma. Initially, it was mistaken as a saccular aneurysm and was just coincident with traumatic SAH. Surgical clipping was performed by our senior neurosurgeon and looked secure. But massive bleeding occurred before complete closure of the dura wound. Opening the wound again, blood gushed out from the junction of the aneurysm and the parent artery. Because preoperative angiography evaluation had revealed good collateral flow from the contralateral VA, the involved segment of VA was trapped. The patient recovered well with uneventful course. Blunt suboccipital trauma may result in traumatic VA injury which may cause catastrophic complications if neglected. The incidence, risk factors, the pathophysiology of traumatic VA aneurysm, and the treatments are reviewed.

The morphometric analysis of the V2 and V3 segments of the vertebral artery: Normal values on MDCT

A potential hazard in midline posterior fossa craniectomy may be the injury of vertebral artery. That's why vertebral artery evaluation prior to surgery may prevent dangerous complications. Advancements in multidetector computed tomography (MDCT) have provided detailed demonstration of the vertebral artery at the craniocervical junction and its relationships with atlas and axis. We aimed to define the normal anatomic relationship of the V2 and V3 part of the vertebral artery on MDCT. In total, 33 patients underwent MDCT angiography scan with suspected cranial aneurysm. V2 and V3 segments of vertebral artery were evaluated. Eight measurements (B, C, D, E, G, H, X, and Y line) were taken from MDCT images. For B and C, a line initially passing through the body of axis and spinous process and determining the midline was formed. Then, the vertical distance of vertebral artery from the level of transverse foramen of axis and loop to this midline was measured. For D and G, the vertical distance of vertebral artery to the midline from the upper and lower margin levels of transverse foramen of atlas was measured after a line establishing the midline passing through the anterior and posterior tubercles of atlas was drawn first. For E, transverse diameter of vertebral artery was measured at the loop level of V2 segment. For H, the vertical distance at the point where vertebral artery entered dura in the line passing from the midline of foramen magnum at anterior–posterior plane was measured. For X and Y, two different points of horizontal part of the vertebral artery were determined. One of these two points was the lateral one which was the origin of the horizontal part in the transverse foramen, the other was the intersection point on atlas. Average distances for both sides from transverse foramen of the axis, the loop of axoatlantal part and the lower border of the atlas of the vertebral artery to the midline were 20.97 mm on the right, 22.29 mm on the left; 27.19 mm on the right, 28.34 mm on the left; and 25.75 mm on the right and 27.21 mm on the left, respectively. Average distances for both sides from the upper border of the atlas, and at its penetration through dura were 27.40 mm on the right, 28.94 mm on the left; and 10.90 mm on the right and 10.93 mm on the left, respectively. Distances between spinous process and intersection of vertebral artery with horizontal part were 35.79 mm on the right and 36.63 mm on the left laterally, and 22.27 mm on the right and 22.62 mm on the left medially. MDCT angiography is a powerful test to demonstrate the vasculature of the head and neck. Bony structures and adjacent vessel morphology can be evaluated by this technique. The evaluation of craniocervical region prior to surgery with MDCT may be helpful to avoid intraoperative vascular injuries.

Symptomatic Ostial Vertebral Artery Stenosis: Treatment with Drug-eluting Stents—Clinical and Angiographic Results at 1-year Follow-up

To evaluate the feasibility and preliminary results of using paclitaxel-eluting stents for angioplasty and to treat symptomatic atherosclerotic ostial vertebral artery (VA) stenosis. Institutional review board approval and written informed consent were obtained for this prospective study. Nine men and one woman (average age, 65.9 years +/- 11.6 [standard deviation]) were included. Inclusion criteria were as follows: (a) Patients had angiographic evidence of VA ostial stenosis of 50% or more or stenosis of more than 45% if the contralateral VA was occluded. (b) Refractory vertebrobasilar ischemia, such as a stroke or transient ischemic attack, occurred while patients were taking one antiplatelet medication with optimal cardiovascular risk factor control. (c) Patients did not have another substantial vertebrobasilar stenotic lesion in the same territory. The primary end point was procedure safety, defined as mortality and permanent neurologic morbidity 30 days after stent placement. The secondary end point was clinical effectiveness, defined as recurrent vertebrobasilar ischemic symptoms within 12 months after stent placement and restenosis greater than or equal to 50% of the treated VA segment within 12 months after stent placement. The degree of stenosis ranged from 46% to 83% (mean, 67.3% +/- 11.9). The technical success rate was 100%. Procedure-related complication rate, mortality rate, and permanent neurologic morbidity rate at 30-day follow-up were 0%. At 12-month follow-up, no patient reported recurrent vertebrobasilar ischemic symptoms or had VA restenosis. This pilot study suggests that use of paclitaxel-eluting stents in angioplasty and to treat symptomatic atherosclerotic ostial VA stenosis are feasible and promising in terms of potential safety and effectiveness in prevention of recurrent ischemia and restenosis. These results could be helpful in the formulation of a larger prospective randomized controlled trial.

Suboccipital segment of the vertebral artery: A cadaveric study

To study the course, relationships, branches and possible anomalies of the vertebral artery in the suboccipital region in adult Indian cadavers. Twenty-one suboccipital segment vertebral artery specimens from embalmed, Indian adult cadavers were dissected and studied. Dissection was performed using microsurgical instruments and was carried out from the skin up to the vertebral artery in layers. The course, relationships and the branches of the vertebral artery were studied and measurements were taken using Vernier calipers. The readings obtained were corroborated with the measurements derived from the digital images using a computer. All the vertebral arteries had a tortuous course and were covered with rich venous plexuses. None of the specimens had an anomalous course. The artery was divided into a vertical segment (Vv) between C2 and C1 vertebra and a horizontal segment (Vh) from the C1 transverse foramina to its dural entry. The mean diameter of the artery was 4.8 mm. The shortest distance of Vv segment from the dural tube was 16.1 mm, and the distance from the C2 ganglion was 7.2 mm. The average length of the Vv segment was 15 mm and the average length of the Vh segment was 35.6 mm. The average of the shortest distance between the vertebral artery and the midline was 13.4 mm. The vertebral artery has a tortuous course and is prone to accidental iatrogenic injury, which can result in devastating neurological sequelae depending on contralateral vertebral artery flow. A thorough anatomical knowledge of this segment is essential for the surgeon who intends to operate in this area.

Anatomical Variations of the Vertebral Artery Segment in the Lower Cervical Spine

Observational study with retrospective computerized tomography (CT) angiography analysis. The purpose of this study is to examine the vertebral artery's course in the V2 segment and define the anatomic variations in the adult population using CT angiography. The V2 segment of the vertebral artery (VA) usually extends from the transverse processes of C6-C2; however, the presence of abnormal VA course has been reported. These variations may predispose a patient to higher risk of iatrogenic vascular injury during anterior cervical surgery. Retrospectively, 700 vertebral arteries on 350 three-dimensional CT angiographies were analyzed. Measurements were taken describing the relationship between the extraosseous portions of the VA to surgical landmarks. In addition, the diameter of the transverse foramen was measured on axial CT images. The VA entered the C6 transverse process in 94.9% of the specimens (664 out of 700 VA courses). Abnormal VA entrance was observed in 5.1% of the specimens (36 VA courses), with entrance into the C4, C5, or C7 transverse foramen 1.6%, 3.3%, and 0.3%, respectively.In 2 of 36 cases (5.6%) of abnormal VA entrance, the extraosseous VA formed an unusual medial loop, and the center of VA was positioned medial to the longus colli muscle. Furthermore, transverse foramens filled with VA were significantly larger than unfilled foramens (P < 0.01), but there was no significant difference between the C7 unfilled foraminal area and unfilled foraminal area above C7 (P = 0.768). The present study confirms the presence of anomalous VA routes in the V2 segment. A preoperativethree-dimensional computerized tomography (CT) angiography with axial images may be useful to identify the presence of an anomalous V2 route when suspected on magnetic resonance imaging or CT. Delineation of this anomaly may reduce the risk of intraoperative VA injury.