Venous organization in the transverse foramen: dissection, histology, and magnetic resonance imaging (original) (raw)
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Cervical venous organization in the transverse foramen
Surgical and Radiologic Anatomy, 2005
The most widely accepted description of venous anatomy in the transverse foramen involves the presence of one or two veins running along and parallel to the external side of the vertebral artery. For most surgeons, the vertebral artery is surrounded by a rete of veins which is continous with the wide sinusoids which surround the thecal sac (internal vertebral venous plexus). The goal of this study was to ascertain the exact structure of the venous system in the transverse canal by micro dissection and histology. Six spinal segments (C1 to C7) removed from cadavers embalmed using 5% diluted formalin or not and studied with or without injection of colored latex after bilateral catheterization of the internal jugular vein, vertebral vein, common carotid artery, and vertebral artery. An anatomical study was performed by optical microscopy. After fixation and decalcification, tissue specimens were stained using hematoxylin-eosin-safran (HES) and immunocytochemical markers including CD43, CD31, and desmine (specific for vascular endothelium). Findings showed that venous blood in the transverse canal flows through a space formed by the periosteum. There was no evidence of a vein inside the transverse canal. The periosteum spans the space between the transverse processes and gives off fibrous leaflets to the artery thus forming a compartmentalized space lined with vascular endothelium around the artery. The venous system in the transverse canal presents itself as a sinus similar to the intracranial sinus structure.
Gross morphology of the bridges over the vertebral artery groove on the atlas
Surgical and Radiologic Anatomy, 2005
The bony bridges of the atlas over the ''groove of the vertebral artery'' are commonly seen in plain radiographs of the cervical spine, and it is a subject of controversy whether they cause compression of the underneath lying vertebral artery. To clarify this we examined a total of 176 dried and complete atlas vertebrae and found the presence of a ''canal for the vertebral artery'' (CVA) in 10.23% and an incomplete ''canal for the vertebral artery'' in 24.43%. The CVA and incomplete CVA is more common in males (11.11% and 24.9%) than in females (9.3% and 24.42%). We found a higher incidence of CVA in laborers (37.5%) than in nonlaborers (4.16%). The incomplete CVA appeared to be more characteristic in the age group of 5-44 years. In the age group of 45-90 years the CVA was characteristic, which probably means that an incomplete CVA is the precursor of a CVA. The superoinferior diameter of the CVA canal ranged from 5.1 to 6.1 mm at the right side and from 4.6 to 5.8 mm at the left side, while the anteroposterior diameter was 5.6-6.9 mm at the right side and 6.1-7.2 mm at the left side. We also found a high incidence of coexistence of CVA and the ''retrotransverse foramen'' (72.22%) which means that because of possible compression of the vertebral veins the blood flow is directed into the small vein of the retrotransverse foramen. Finally, in 93.5% of unilateral CVA a deeply excavated contralateral ''groove of the vertebral artery'' was found.
Microsurgical anatomy of the internal vertebral venous plexuses
Surgical and Radiologic Anatomy, 1998
Few studies have been done about the venous vascularization of the spine since neuroradiologic studies in the 1960s and 70s. The aim of this study was to clarify the topography of the internal vertebral venous plexuses in relation to the posterior longitudinal ligament and the dura. The relationships of the vv. were studied at different levels of the spine. The internal vertebral venous system of seven cadavers was injected with a blue bicomponent silicon rubber. It consisted with an anterior and a posterior venous plexus. At the cervical level, the anterior longitudinal vv. are located in a dehiscence of the periosteal layer, in the lateral part of the spinal canal. At each level, they joined the contralateral one at the midline by a retrocorporeal v. located behind the posterior longitudinal ligament. No vv. were found in the epidural space. There was a major development of the retrocorporeal v. of the axis, but it did not receive any venous drainage from the vertebral body. At the thoracic and lumbar levels, the anterior venous plexuses remain within a dehiscence of the periosteal layer, which is thinner. The retrocorporeal vv. become pre-ligamentous. We did not find any posterior venous plexuses at the cervical level, but they were evident at the thoracic level and became more voluminous and sinusoidal in the lumbar region.
Surgical and Radiologic Anatomy, 2005
The vertebral artery (VA) is often involved in the occurrence of complications after spinal manipulative therapy. Due to osteophytes compressing the VA anteriorly from the uncinate process or posteriorly from the facet complex, the VAs are susceptible to trauma in the transverse foramina. Such altered anatomical configurations are of major clinical significance, as spinal manipulations may result in dissection of the VA with serious consequences for the blood supply to the vertebrobasilar region. The purpose of this study is to describe numerous structural features of the third to seventh cervical vertebrae in order to contribute to the understanding of pathological conditions related to the VA. The minimal and maximal diameter of 111 transverse foramina in dry cervical vertebrae were studied. The presence of osteophytes and their influence on the VA were evaluated at the vertebral body and at the superior and inferior articular facets. The diameter of the transverse foramina increased from C3 to C6, while the transverse foramina of C7 had the smallest diameter. At all levels the mean dimensions of the left foramina were greater than those of the right side. Osteophytes from the uncinate process of C5 and C6 vertebrae were found in over 60% of dry vertebrae. Osteophytes from the zygapophyseal joints were more frequent at C3 and C4 vertebrae. About half of the osteophytes of the uncinate and of the superior articular process partially covered the transverse foramina. This was less common with those of the inferior articular facets. Osteophytes covering the transverse foramen force the VAs to meander around these obstructions, causing narrowing through external compression and are potential sites of trauma to the VAs potentially even leading to dissection. We strongly advocate that screening protocols for vertebrobasilar insufficiency (VBI) be used prior to any manipulation of the cervical spine and should include not only extension and rotation but any starting position from which the planned manipulation will be performed.
Patient Safety in Surgery, 2015
Background: The V2 segment of the vertebral artery is very vulnerable to injury during cervical spine surgery. The incidence of vertebral artery injury during anterior cervical spine procedures is reported to be 0.22-2.77 %. This is partially due to its variable course while running in the transverse foramens of the cervical vertebrae. Case presentation: The course of the vertebral artery in the dissected cadaver of a 79 year old female is presented. Dissection of the left vertebral artery showed that the 5 th nerve root passes in front of the vertebral artery in the 4 th intertransverse space. Further exploration showed that although vertebral artery at first passed at the back of the nerve root it curved downwards again and after passing underneath the 5 th nerve root entered the 4 th vertebral body. After making a loop in the left half of the vertebrae, vertebral artery ran anterior to the nerve root and after entering the 4 th transverse foramen showed up in the 3 rd intertransverse space. The shortest distance of the vertebral artery to the midline at the 4 th vertebrae level was 4.78 mm. Conclusions: To our knowledge this case is the first report of a nerve root lying anterior to the vertebral artery in the intertransverse space of the cervical spine. Additionally vertebral artery has never been reported to be so close to the midline. This report signifies the importance of obtaining MRI or contrast enhanced CT scan prior to any cervical spine surgery in the vicinity of the vertebral artery including corpectomies and also careful approach to the intertransverse space during the operation.
Neurospine
Objective: Vertebral artery injuries during posterior cervical foraminotomy are rare, but can be fatal. Therefore, we investigated the anatomical correlation between the lateral recess and the vertebral artery. Methods: On axial cuts of cervical magnetic resonance imaging from 108 patients, we measured the distance between the vertebral arteries and the medial border of the facet joints. The anatomical vertebro-facet distance (AVFD), surgical vertebro-facet distance (SVFD), and vertebro-facet angle (VFA) were measured. Results: The mean AVFD values on the right side at the C3-4, C4-5, C5-6, and C6-7 levels showed statistically significant differences. On the right side, the mean SVFD values were equivalent to the AVFD values. The mean values of the VFA on the right side at all levels showed statistically significant differences. For all measurements, the greatest differences were seen between the C5-6 and C6-7 levels, and higher levels were associated with smaller distances from the lateral recess. The mean values of the AVFD on the right and left sides showed statistically significant differences at all levels, and the distances on the left were smaller than those on the right. Conclusion: The vertebral artery is closer to the lateral recess at higher cervical levels than at lower cervical levels. The largest distances were found at the C5-6 and C6-7 levels, and the left vertebral arteries were closer to the lateral recess than the right vertebral arteries.
Anatomical Variations of the Vertebral Artery in the Upper Cervical Spine
Regional Anesthesia and Pain Medicine, 2018
Background and Objectives: Accidental breach of the vertebral artery (VA) during the performance of cervical pain blocks can result in significant morbidity. Whereas anatomical variations have been described for the foraminal (V2) segment of the VA, those involving its V3 portion (between the C2 transverse process and dura) have not been investigated and may be of importance for procedures targeting the third occipital nerve or the lateral atlantoaxial joint. Methods: Five hundred computed tomography angiograms of the neck performed in patients older than 50 years for the management of cerebrovascular accident or cervical trauma (between January 2010 and May 2016) were retrospectively and independently reviewed by 2 neuroradiologists. Courses of the VA in relation to the lateral aspect of the C2/C3 joint and the posterior surface of the C1/C2 joint were examined. For the latter, any medial encroachment of the VA (or one of its branches) was noted. The presence of a VA loop between C1 and C2 and its distance from the upper border of the superior articular process (SAP) of C3 were also recorded. If the VA loop coursed posteriorly, its position in relation to 6 fields found on the lateral aspects of the articular pillars of C2 and C3 was tabulated. Results: At the C1/C2 level, the VA coursed medially over the lateral quarter of the dorsal joint surface in 1% of subjects (0.6% and 0.4% on the left and right sides, respectively; P = 0.998). A VA loop originating between C1 and C2 was found to travel posteroinferiorly over the anterolateral aspect of the inferior articular pillar of C2 in 55.5% of patients on the left and 41.9% on the right side (P < 0.001), as well as over the SAP of C3 in 0.4% of subjects. When present in the quadrant immediately cephalad to the C3 SAP, VA loops coursed within 2.0 ± 1.5 and 3.3 ± 2.5 mm on the left and right sides, respectively, of its superior aspect (P < 0.001). Conclusions: The VA commonly travels adjacent to areas targeted by third occipital nerve procedures and more rarely over the access point for lateral atlantoaxial joint injections. Modifications to existing techniques may reduce the risk of accidental VA breach.
Vertebral artery in relationship to C1-C2 vertebrae: an anatomical study
Neurology India, 2004
Ten randomly selected adult cadaveric specimens were dissected to analyse the anatomy of the vertebral artery during its course from the C3 transverse process to its entry into the spinal dural canal at the level of C1. In addition, 10 dry cadaveric C1-C2 bones were studied. The course of the artery and the parameters relevant during surgery in the region are evaluated. Ten adult cadaveric specimens and 10 adult dry cadaveric C1 and C2 bones were studied. In five cadaveric specimens, the arteries and veins were injected with coloured silicon. The artery during its course from the transverse process of C3 to the transverse process of C2 was labelled as V1 segment, the artery during its course from the C2 transverse process to the C1 transverse process was labelled as V2 segment and the segment of the artery after its exit from the transverse foramen of C1 to the point of its dural entry was labelled as V3 segment. The relationship of the artery to the C1-2 joint and facets, distance ...
Morphometric analysis of the vertebral artery groove of the first cervical vertebra (atlas)
Pan Arab Journal of Neurosurgery, 2009
Background: Variations in the morphometry of the vertebral artery groove which presents on the superior surface of the posterior arch of the atlas behind its lateral mass may complicate surgical procedures in craniovertebral junction surgery. This necessitates preoperative information about the vertebral artery groove. Objective: The present study aimed at assessment of the quantitative and qualitative anatomy of the vertebral artery groove of the atlas on 76 dry specimens with comprehensive analysis. Methods: This included the study of different linear parameters of the vertebral artery groove such as the distance from the midline, the thickness, the depth of the lateral and medial entrances, the depth of the transverse foramen and the width of the transverse foramen. In addition, the different forms of posterior and lateral bridging over the groove and their percentages were assessed. Results: It was found that the minimum distance from the midline to the medial most edge of the vertebral artery groove in the inner and outer cortex of the posterior arch were 5 and 15 mm respectively. These data suggested that dissection of the posterior aspect of the posterior arch should remain 5 and 15 mm on the inner and outer cortex from the midline. It was also found that 44 (57.96%) of the examined specimens presented with a bridge formation which projects over the vertebral artery groove. From these 44 atlas presented with a bridge formation, 42 (55.26%) presented with partial bridges and 2 (2.63%) presented with complete posterior bridges. These bridges may interfere with the normal function of vertebral artery. Conclusion: It was concluded that before any craniovertebral intervention is performed, collection of the morphometric data of the vertebral artery groove must be carried out. (p66-71)