Course Of Vertebral Artery Research Articles

A case of double aortic arch accompanied by sub-aortic and pre-aortic left brachiocephalic veins and anomalous origin and course of left vertebral artery

During the elective course of human dissection at the University of Toyama in 2007, we encountered a rare case of double aortic arch accompanied by sub- and pre-aortic left brachiocephalic veins (LBV), and anomalous origin and course of the left vertebral artery in a Japanese elderly female. The double aortic arch formed a complete vascular ring that encircled the trachea and the esophagus. The sub-aortic LBV traversed below the aortic arches between the ascending aorta and the trachea. In addition, there was a small pre-aortic LBV passing anterior to the origins of the aortic arches. The left vertebral artery originated from the left aortic arch and entered the transverse foramen of C3, while the right vertebral artery originated from the right subclavian artery and entered the transverse foramen of C6.

Posterior Atlantoaxial Screw-Rod Fixation in a Case of Aberrant Vertebral Artery Course Combined with Bilateral High-Riding Vertebral Artery

We present a case of posterior atlantoaxial screw-rod fixation in a patient with an aberrant vertebral artery (VA) course combined with bilateral high-riding VA. An aberrant VA which courses below the posterior arch of the atlas (C1) that does not pass through the C1 transverse foramen and without an osseous anomaly is rare. However, it is important to consider an abnormal course of the VA both preoperatively and intraoperatively in order to avoid critical vascular injuries in procedures which require exposure or control of the VA, such as the far-lateral approach and spinal operations.

Image fusion for preoperative evaluation of vertebral artery in a patient with atlantoaxial vertical subluxation and chronic renal failure

For preoperative evaluation of the vertebral artery (VA) at the craniovertebral junction, 3-dimensional (3-D) computed tomography (CT) angiography can simultaneously and precisely depict the location of the VA and the circumferential osseous tissues. However, this procedure has the risk of contrast-induced nephropathy, especially when patients have pre-existing renal impairment. We report the case of a 73-year-old woman with rheumatoid arthritis and concomitant chronic renal failure in whom severe myelopathy developed due to atlantoaxial vertical subluxation and subaxial subluxation. We planned to perform C1 laminectomy and C3-C7 laminoplasty, but to avoid the risk of intraoperative VA injury, we applied a fusion image technique of 3-D magnetic resonance (MR) angiography and co-registered 3-D CT that allowed for virtual assessment preoperatively of the VA courses, instead of 3-D CT angiography. Through the 3-D hybrid MR angiography-CT images, we could predict, in detail, the VA courses and the surrounding bony structures. At surgery, we found that the locations of the VAs were identical to that predicted on the preoperative image fusion analysis. We conclude that our image fusion techniques possess accurate diagnostic value for detecting arterial course, and could be applicable for patients in whom administration of contrast media should be avoided due to specific conditions, such as drug allergy and chronic renal failure.

Anomalous Variations of the Origin and Course of Vertebral Arteries in Patients with Retroesophageal Right Subclavian Artery

We present two rare cases of anomalous vertebral artery (VA) with retroesophageal right subclavian artery. One patient had a right VA arising from the right common carotid artery (CCA), and a left VA originating from the third branch off the aorta. Both VAs ascended anteriorly to the transverse foramen of C5 to C6 vertebra and entered the transverse foramen of C4. The other patient had a right VA arising from the right CCA and entering the transverse foramen of C5. The presence of anomalous variations of the origin and course of vertebral artery might have serious implications in angiographic and surgical procedures, and it is of great importance to be aware of such a possibility.

Unilateral Posterior Atlantoaxial Transarticular Screw Fixation in Patients with Atlantoaxial Instability : Comparison with Bilateral Method

Bilateral C1-2 transarticular screw fixation (TAF) with interspinous wiring has been the best treatment for atlantoaxial instability (AAI). However, several factors may disturb satisfactory placement of bilateral screws. This study evaluates the usefulness of unilateral TAF when bilateral TAF is not available. Between January 2003 and December 2007, TAF was performed in 54 patients with AAI. Preoperative studies including cervical x-ray, three dimensional computed tomogram, CT angiogram, and magnetic resonance image were checked. The atlanto-dental interval (ADI) was measured in preoperative period, immediate postoperatively, and postoperative 1, 3 and 6 months. Unilateral TAF was performed in 27 patients (50%). The causes of unilateral TAF were anomalous course of vertebral artery in 20 patients (74%), severe degenerative arthritis in 3 (11%), fracture of C1 in 2, hemangioblastoma in one, and screw malposition in one. The mean ADI in unilateral group was measured as 2.63 mm in immediate postoperatively, 2.61 mm in 1 month, 2.64 mm in 3 months and 2.61 mm in 6 months postoperatively. The mean ADI of bilateral group was also measured as following; 2.76 mm in immediate postoperative, 2.71 mm in 1 month, 2.73 mm in 3 months, 2.73 mm in 6 months postoperatively. Comparison of ADI measurement showed no significant difference in both groups, and moreover fusion rate was 100% in bilateral and 96.3% in unilateral group (p=0.317). Even though bilateral TAF is best option for AAI in biomechanical perspectives, unilateral screw fixation also can be a useful alternative in otherwise dangerous or infeasible cases through bilateral screw placement.

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.

P33. Anatomical Variations of the V2 Segment of the Vertebral Artery: Analysis by Three Dimensional Computed Tomography Angiography

BACKGROUND CONTEXT: Injuries of vertebral artery are rare but can cause disastrous complication after anterior decompression surgery of the cervical spine. The V2 segment of vertebral artery usually extends from the transverse processes of C6 to C2; however, the presence of abnormal vertebral artery course has been reported.

Significance of Laminar Screw Fixation in the Subaxial Cervical Spine

We retrospectively reviewed 11 patients who underwent laminar screw fixation in the subaxial cervical spine. In 4 patients, laminar screws were inserted for posterior cervical arthrodesis, and in 7 patients it was used for fixation of the open laminae during laminoplasty. In this study, the author describes the technique and surgical results of translaminar screw placement in the subaxial cervical spine. The use of laminar screws for fixation of the second cervical vertebra and upper thoracic vertebrae has been introduced as an important technique in spinal surgery because they can avoid injury to adjacent neurovascular structures. However, there have been no reports of translaminar screw use in the subaxial spine including C7. In this study, we describe the use of translaminar screws for fixation of the subaxial cervical spine in cases of degenerative or traumatic spine disease. Between June 2006 and March 2007, 34 translaminar screws were placed in 11 patients to treat trauma or degenerative disease: 6 at C7, 6 at C6, 7 at C5, 7 at C4, 7 at C3, and 1 at T1. There were 6 women and 5 men. The ages ranged from 23 to 87 years with a mean age of 61.3 years. All patients were evaluated at 6 weeks, as well as at 3 and 6 months using flexion and extension lateral radiographs. Patients requiring fusion were also evaluated with computed tomography at 3 and 6 months to verify arthrodesis. The mean follow-up period was 5.7 months, at which time there was no significant complications from laminar screw placement, except for 2 asymptomatic breaches of the dorsal lamina cortex. Sound bone fusion was identified in cases where arthrodesis was the goal. No screw pullout or avulsion was identified in the laminoplasty cases. The translaminar screw method avoided damaging vascular structures, especially when the vertebral artery courses in the C7 transverse foramen, and it maintains solid stabilization of the subaxial cervical spine. This technique has 2 important advantages to currently used techniques: it is simpler and is not limited by the position of vascular structures. Therefore, it may be applicable to a wider number of patients, especially as it may be used in the subaxial cervical spine.

The anatomic study on replacement of artificial atlanto-odontoid joint through transoral approach

In order to provide anatomical basis for transoral approach (TOA) in dealing with the ventro lesions of craniocervical junction, and the design and application of artificial atlanto-odontoid joint, microsurgical dissecting was performed on 8 fresh craniocervical specimens layer by layer through transoropharyngeal approach. The stratification of posterior pharyngeal wall, course of vertebral artery, adjacent relationship of atlas and axis and correlative anatomical parameters of replacement of artificial atlanto-odontoid joint were observed. Besides, 32 sets of atlanto-axial joint in adults' fresh bony specimens were measured with a digital caliper and a goniometer, including the width of bony window of anterior arch of atlas, the width of bony window of axis vertebra, the distance between superior and inferior two atlas screw inserting points, the distance between two axis screw inserting points etc. It was found that the width of atlas and axis which could be exposed were 40.2+/-3.5 mm and 39.3+/-3.7 mm respectively. The width and height of posterior pharyngeal wall which could be exposed were 40.1+/-5.2 mm and 50.2+/-4.6 mm respectively. The distance between superior and inferior two atlas screw inserting points was 28.0+/-2.9 mm and 24.0+/-3.5 mm respectively, and the distance of bilateral axis screw inserting points was 18.0+/-1.2 mm. The operative exposure position through TOA ranged from inferior part of the clivus to the superior part of the C3 vertebral body. Posterior pharyngeal wall consisted of 5 layers and two interspaces: mucosa, submucosa, superficial muscular layer, anterior fascia of vertebrae, anterior muscular layer of vertebrae and posterior interspace of pharynx, anterior interspace of vertebrae. This study revealed that it had the advantages of short operative distance, good exposure and sufficient decompression in dealing with the ventro lesions from the upper cervical to the lower clivus through the TOA. The replacement of artificial atlanto-odontoid joint is suitable and feasible. The design of artificial atlanto-odontoid joint should be based on the above data.

Variation in the origin and course of the left vertebral artery – Embryological basis and its clinical significance – A case study

Variation in the origin and course of the left vertebral artery – Embryological basis and its clinical significance – A case study

C1-2 Transarticular Screw Fixation in High-riding Vertebral Artery: Suggestion of New Trajectory

A significant drawback of atlantoaxial transarticular screw fixation is a potential risk of vertebral artery injury, especially with a high-riding type. The authors propose a relatively safe trajectory in cases of high-riding vertebral artery by using the 3-dimensional computerized tomography image reconstruction programs. Twelve consecutive patients with a pathologic condition in atlantoaxial complex were prospectively analyzed. Five other patients, whose high-riding vertebral arteries were incidentally found during the 3-dimensional computerized tomography performance for other cervical pathologic conditions, were also included. The preoperative screw simulation images, convergence angle, and caudal tilting angle for each screw were obtained from each patient. Of 17 subjects, 7 had high-riding vertebral artery unilaterally and 1 had bilaterally. All 12 patients with pathologic atlantoaxial complex, including 2 unilateral and 1 bilateral high-riding vertebral artery, had atlantoaxial transarticular screw fixation. For these 3 patients, the entry point and the trajectory for screw were moved more superiorly and medially as in cases with C2 pedicle screwing. The mean convergence angle and caudal tilt angle obtained during screw simulation for patients with high-riding vertebral arteries was 17.6 and 38 degrees compared with 21 and 53.3 degrees for patients with normal course of vertebral artery. It was possible to insert transarticular screws safely in patients with high-riding vertebral artery guided by preoperative screw insertion simulation program.

Traumatic C6–7 subluxation with anomalous course of vertebral arteries treated with pedicle screw/rod fixation

The authors report the case of a 62-year-old woman who suffered an accidental fall and complained of severe neck pain and right C-7 radiculopathy. A right C6-7 facet fracture-subluxation was diagnosed. Bone fragments impinged on the right C-7 nerve root at the neural foramen. The bilateral vertebral arteries (VAs) ascended at the anterior aspect of C-6 and C-5 and entered the transverse foramen at the C-4 level. Based on findings of anomalous VAs, the authors applied a pedicle screw (PS)/rod system to effect surgical correction of the deformity. Intraoperatively, they successfully performed reduction of the subluxation, decompression of the impinged nerve root, and minimum single-segment fusion involving the placement of a PS/rod system. After surgery, the patient's neurological deficit dramatically improved and spinal fusion was completed without any loss of deformity correction. Prior to surgery for cervical injuries, the possible presence of an abnormal VA course should be considered. Preoperative detection of anomalous VAs will affect decisions on the appropriate corrective surgery option in cases of cervical spine injuries.

Isolated Hypoglossal nerve palsy due to amyloid cervical arthropathy in long term hemodialysis

Sirs: Isolated peripheral hypoglossal nerve palsy is rare and it is caused by primary or secondary tumors of the skull base, leptomeningeal metastases, trauma, carotid artery dissection, surgery or aneurysms of the carotid artery, dural arteriovenous fistula, Chiari malformation, otorhinolaryngological and anesthesiological procedures, radiation, infectious diseases (borreliosis, mononucleosis) and rarely an anomalous vertebral artery course [1,2]. To our knowledge we report the first case of XIIth nerve palsy due to compression by uremic arthropathy. A 69 year-old woman was admitted for a subacute onset of a continuous stabbing pain of the right cervical and occipital regions, associated with difficulty in moving her tongue and in articulating words. Neurological examination showed only mild dysarthria and right hypoglossal nerve palsy, with right hemiatrophy of the tongue (Fig. 1). The patient had required of hemodialytic treatment beginning 14 years ago because of end-stage renal disease secondary to non-steroidal antinflammatory drugs abuse for migraine, and, since then, she had undergone four surgical interventions for total hip arthroplasty and also for bilateral carpal tunnel syndrome. Brain CT was normal. Doppler ultrasound and MR angiography of supraortic vessels excluded the presence of carotid artery dissection. Neoplastic, autoimmune, rheumatological, and infectious diseases were excluded with appropriate tests. Brain and cervical MRI showed the presence of periodontoid soft tissue, hypointense in T1 and T2weighted images, without gadolinium enhancement, extending from the C2 dens, mainly on the right, and reaching the foramen magnum and the medial surface of occipital condyle (Figure 2). This tissue involved the hypoglossal nerve before it entered the hypoglossal canal and occupied the medullary cistern without compressing the medulla. The picture was consistent with synovial hypertrophy. Skull base CT showed small erosions of the dens with well-defined lytic areas (geodes), without atlanto-axial dislocation. Disc herniation, narrowing of the intervertebral space, bone erosion, geodes and mild ankylosis were also detected at the cervical level by CT and MRI. The picture was consistent with destructive spondyloarthropathy (DSA) due to chronic uremia.

Morphological Change of Unruptured Vertebral Artery Dissection on Serial MR Examinations

Basi-parallel anatomical scanning (BPAS)- MRI is a simple MRI technique to reveal the surface contour of the intracranial vertebrobasilar artery. The purpose of this study was to investigate the usefulness of BPAS-MRI for observing the temporal course of unruptured vertebral artery (VA) dissection in patients by means of serial MR examinations. Since April 2003, we performed serial MR examinations in four patients with unruptured acute vertebral artery dissection. The frequency of the MR examinations during the follow-up period in each patient varied from twice within seven months to five times within 19 months. Both MRA and BPAS-MRI were obtained in each MR examination. We investigated the course of morphological changes within the dissected artery on BPASMRI (outer contour) and on MRA (inner lumen). Although the initial MRA showed fusiform dilatation, irregular stenosis or normal caliber at the dissected lesion, the initial BPAS-MRI disclosed fusiform dilatation in all of the four patients. In two patients, MRA finding of the VA lesion had changed, though the fusiform appearance had been stationary on BPAS-MRI. Then both dissolution of the fusiform dilatation on BPAS-MRI and normalization of the inner luminal caliber on MRA were confirmed within nine months. In one patient, fusiform dilatation on both BPAS-MRI and MRA resolved simultaneously on the MR examination at eight months after the initial symptom. In another patient, fusiform dilatation of the outer contour was still enlarging on BPAS-MRI ten months after the onset, though the fusiform dilatation on MRA had been stationary since the eighth week. We performed endovascular coil embolization in this patient eleven months after the initial symptom. Resolution of the fusiform dilatation on BPAS-MRI should be a healing sign of VA dissection. Persisting the fusiform dilatation or progressively enlarging outer contour on BPASMRI may be an unstable sign. BPAS-MRI provides more information about the instability of the dissected lesion. We should obtain not only MRA but also BPAS-MRI for the course observation of unruptured VA dissection.

Aberrant vertebral artery course in a case of Chiari malformation and occipitoatlantal assimilation

tThe authors report an unusual case of a patient with combined vertebral artery and Chiari malformation anomalies. Unless such anomalies are properly recognized prior to decompression and fusion, this condition can have grave surgical consequences. The diagnostic and surgery-related implications of such anomalous codiseases are discussed.

Constructs Incorporating Intralaminar C2 Screws Provide Rigid Stability for Atlantoaxial Fixation

An in vitro biomechanical study of C1-C2 posterior fusion techniques using a cadaveric model. To investigate the acute stability afforded across the atlantoaxial segment by a novel technique that uses intralaminar screws in C2, and to compare these results to the stability obtained using a C2 pedicle fixation technique. There are numerous techniques available for rigidly coupling C1 and C2. It has been shown that screw techniques provide higher acute stability than wiring practices. However, many of these methods that use screw fixation in C2 can be technically difficult, especially in cases in which there is an aberrant vertebral artery course or if the C2 pedicle is not large enough to accommodate the instrumentation. A novel technique that uses intralaminar screws in C2 with C1 pedicle screws and bilateral longitudinal rods has been recently developed in an effort to overcome many of these issues. To date, there are no published reports as to whether this new technique provides equivalent (or better) fixation to the currently accepted methods. Six fresh-frozen human cadaveric cervical spines (C0-C4) were used in this study. Specimens were tested in their intact condition after destabilization via odontoidectomy, and after implantation of 3 different fixation constructs: (1) the Harms technique, 2 pedicle screws in C2, (2) a single C2 pedicle screw and a single C2 intralaminar screw, and (3) a construct having bilateral intralaminar C2 screws. Pure moment loading in flexion/extension, lateral bending, and axial rotation was applied to the occiput. Subsequent relative intervertebral rotations were determined using a 3 camera system. Range of motion for the intact, destabilized, and 3 fixation scenarios was determined, and statistical analysis was performed using one-way analysis of variance Fisher least-significant-difference post hoc test for multiple comparisons. The data indicate that odontoidectomy significantly increased C1-C2 motion in flexion/extension and lateral bending. All 3 fixation techniques significantly reduced motion compared to the intact and destabilized cases. There were no statistically significant differences between the C2 intralaminar and pedicle screw techniques. The results clearly indicate the potential of the intralaminar screw technique to provide stability that is equivalent to methods currently used. Given the serious complications that can follow vertebral artery injury and the decreased likelihood of injury by avoiding placement of C2 pedicle screw(s) and C1-C2 transarticular screw(s), strong consideration should be given to using a construct that incorporates C2 intralaminar screw(s).

Fenestration of Vertebral Artery at the Craniovertebral Junction in Down Syndrome: A Case Report

Case report of a Down syndrome patient with right vertebral artery fenestration and abnormalities of the craniovertebral junction. Describe the utility of 3-dimensional computed tomography angiography for evaluating vertebral artery anomalies before surgery. Previous reviews evaluating catheter angiograms identified various anomalies of vertebral artery at the craniovertebral junction. The frequency of vertebral artery anomalies is increased in patients having osseous anomalies at the craniovertebral junction. Down syndrome is associated with a high incidence of bone abnormalities at the craniovertebral junction, but there have been no published reports of vertebral artery anomalies per se at the craniovertebral junction. A 16-year-old woman with trisomy 21 presented with gait abnormalities and myelopathy in association with bone abnormalities at the craniovertebral junction, including hypoplastic odontoid and ossiculum terminale. Computed tomography angiography showed that right vertebral artery bifurcated after exiting the C2 transverse foramen with one branch passing through the C1 transverse foramen, whereas the other turned posteromedially and entered the spinal canal between C1 and C2. Occipito-C2 posterior fusion was performed with a rod and screw system. Intraoperatively, the course of the anomalous right vertebral artery was identified by Doppler angiography, and the surgical approach was modified to allow safe pedicle screw insertion while avoiding vertebral artery injury. After surgery, myelopathy resolved within 3 months. Before corrective surgery of craniovertebral junction anomalies in patients with Down syndrome, the possibility of vertebral artery anomalies associated with abnormal craniovertebral junction anatomy should be considered. With preoperative 3-dimensional computed tomography angiography, we can precisely identify the anomalous vertebral artery and modify the surgical approach to reduce the possible risk of intraoperative vertebral artery injury in advance.

Transesophageal echocardiographic identification of right vertebral artery.

We describe a transesophageal technique for identifying the origin and precervical course of the right vertebral artery with the probe positioned in the upper esophagus. The technique was successful in 9 of 11 patients in whom it was attempted.

Identification of vertebral arteries on CT of the chest.

Knowledge of the superior mediastinal course of the vertebral arteries is important for radiologists who evaluate chest CT, particularly in the setting of trauma, when planning a percutaneous interventional procedure or for pre-operative planning. Our aim was to determine how often the vertebral arteries could be identified on chest CT studies. Contrast enhanced chest CT studies from 100 consecutive patients were reviewed, with specific attention to the vertebral arteries in the superior mediastinal and thoracic outlet regions. The left vertebral artery was identified in 85 patients and the right vertebral artery in 76 patients. Non-visualization of a vertebral artery was usually owing to proximal venous occlusion with extensive collateral vessels in the expected location of the vertebral arteries, local lymphadenopathy, poor contrast bolus technique or local beam hardening artefact. Radiologists need to alert surgeons planning resection of mass lesions in this region to the location of the vertebral arteries. It is also important to note that a vertebral artery was not identified on chest CT in 24% of patients.

Tortuous course of the vertebral artery and anterior cervical decompression: a cadaveric and clinical case study.

Both the cadaveric and clinical examples of anomalous vertebral artery courses are described. The incidence of this anomaly in the general population and recognition, complications, and treatment options for these patients when undergoing anterior cervical decompression are discussed. Cadaveric study: In this study vertebral artery's course through the cervical spine in the adult population was analyzed. The relation between an abnormal vertebral artery course and surgical landmarks are described. Clinical study: Complications and alternative treatment methods for decompression in patients with the anomaly are described. The incidence of anomalous vertebral artery course is low, but failure to recognize a medially located vertebral artery may result in a life-threatening iatrogenic injury during decompression. Neither the relation between the vertebral arteries and the surgical landmarks nor the guidelines for decompression in the face of a tortuous vertebral artery have been well described. Transverse foramens of the cervical spine were measured in 222 cadaveric spines. The measurements were taken describing the relation between transverse foramens and other surgical landmarks. Three patients with anomalies were identified in clinical practice. The complications and treatment options are identified in these patients. In the cadaveric specimens, a 2.7% incidence of tortuous vertebral artery course was identified. In these abnormal specimens, the transverse foramen was located an average of 0.14 mm medial to the joint of Luschka. In one patient, the abnormal course of the vertebral artery was recognized after laceration of the artery during a routine corpectomy. Anomalies in the other two patients were recognized before surgery, and the patients underwent modified anterior decompression by combining a discectomy at the anomalous level with a corpectomy at other levels. Vertebral artery ectasia is identifiable on axial magnetic resonance or computed tomographic images. Aberrant vertebral artery is rare. Preoperative recognition and appropriate modification of anterior decompression can yield excellent clinical results without risking significant complications.