Anatomical variations of the vertebral artery segment in the lower cervical spine: analysis by three-dimensional computed tomography angiography

Applied anatomy of the vertebral arteries for endovascular neurointerventions

The vertebral arteries (VAs) constitute most of the arterial supply to the posterior cerebral vascular circulation. They have anatomical specificities and may have variants that are critical for neurointerventionists to recognize in order to design open or endovascular surgical treatment. This review addresses each segment of the VA including its origin and discusses the branches and relevant anatomical features for neurointerventions.

Safety and Efficacy of Intraoperative Doppler Sonography-Assisted Cervical Pedicle Screw Fixation-A Retrospective Comparison with Conventional Pedicle Screw Implantation

STUDY DESIGN

A Retrospective Cohort Study.

OBJECTIVE

To introduce a new Doppler sonography-assisted pedicle screw fixation technique that enables vertebral artery (VA) monitoring during surgery and compares the accuracies of Doppler sonography-assisted cervical pedicle screw fixation and the conventional technique.

METHODS

This retrospective study was performed on 164 consecutive patients that underwent pedicle-based screw fixation from C2 to C6 between January 2013 and August 2020. Surgery was performed without intraoperative Doppler sonography in 84 cases (the Control group) or with intraoperative Doppler sonography in 80 cases (the Doppler group). Proper positioning of pedicle screws was graded, and the incidences of VA injury and screw breach in the Control and Doppler groups were compared.

RESULTS

Three hundred and ninety-nine screws were placed in the 164 patients (Doppler, 186 screws; Control, 213 screws). The percentages of well-positioned screws in the two groups were significantly different (Doppler, 97.8%; Control, 85.0%). There were two cases of VA injury in the Control group, an incidence of 2.4%, but no case in the Doppler group.

CONCLUSION

Doppler sonography can be used intraoperatively to help guide the trajectory of the cervical pedicle screw insertion. It can detect the VA inside the screw trajectory and may reduce the risk of VA injury during cervical pedicle screw fixation.

The Vertebral Artery: A Systematic Review and a Meta-Analysis of the Current Literature

(1) Background. The anatomical variations of the vertebral arteries (VAs) have a significant impact both in neurosurgery and forensic pathology. The purpose of this study was to evaluate the variational anatomy of the vertebral artery. We evaluated anatomical aspects regarding the V1 and V2 segments of the VA: origin, course, tortuosity, hypoplasia, and dominance, and established the prevalence of each variation. (2) Methods. We conducted a systematic search in PubMed and Google Scholar databases, up to December 2022. Sixty-two studies, comprising 32,153 vessels, were included in the current meta-analysis. We used a random-effects model with a DerSimonian-Laird estimator. The confidence intervals were set at 95%. The heterogeneity between studies was assessed using I². The funnel plot and Egger's regression test for plot asymmetry were used for the evaluation of publication bias. Statistical significance was considered at p < 0.05. (3) Results. The most common site for the origin of both VAs was the subclavian artery. The aortic arch origin of the left VA had a prevalence of 4.81%. Other origins of the right VAs were noted: aortic arch (0.1%), right common carotid artery (0.1%), and brachiocephalic trunk (0.5%). Ninety-two percent of the VAs entered the transverse foramen (TF) of the C6 vertebra, followed by C5, C7, C4, and least frequently, C3 (0.1%). Roughly one out of four (25.9%) VAs presented a sort of tortuosity, the transversal one representing the most common variant. Hypoplasia occurred in 7.94% of the vessels. Left VA dominance (36.1%) is more common, compared to right VA dominance (25.3%). (4) Conclusions. The anatomy of the VA is highly irregular, and eventual intraoperative complications may be life-threatening. The prevalence of VA origin from the subclavian artery is 94.1%, 92.0% of the VAs entered the TF at C6, 26.6% were tortuous, and 7.94% were hypoplastic.

Cervical rotational osteotomy for correction of axial deformity in a patient with ankylosing spondylitis

PURPOSE

Severe cervical axial deformity associated with ankylosing spondylitis (AS) is rare in clinic, and there are little concerns about surgical treatment of axial deformity associated with AS. The case study aims to show the surgical technique to perform cervical rotational osteotomy.

METHODS

We present the case of a young AS patient whose neck was fixed in a left-rotational posture at 18°, requiring his trunk to be turned to the right to look forward visually. This made his gait appear to be limping, inconveniencing him with great difficulty. In order to correct this deformity, we performed a novel cervical rotational osteotomy through a one-stage posterior-anterior-posterior approach. Firstly, we performed laminectomies of C7 and T1, followed by a C7/T1 facetectomy with release of the bilateral C8 nerve roots. Next, we performed C7/T1 discectomy, bony resection of the lateral body and uncovertebral joints. The head of the patient was then rotated manually, so that both his face and torso were simultaneously facing frontward. Finally, rods spanning the screws from C6 to T2 were fixed.

RESULTS

Postoperatively, the patient's axial malalignment was significantly improved, and he was able to walk normally. Surgical outcomes were well maintained at a 3-year follow-up.

CONCLUSION

Through this case, we hope to draw the attention to spinal axial deformity and provide a reference point in the surgical treatment of spinal axial deformity.

The segmentation of the vertebral artery: An ambiguous anatomical concept

The course of the vertebral artery from its subclavian artery origin up to its termination at the vertebrobasilar junction is divided into four segments (V1-V4). This segmentation, based on schemes that have evolved since the late nineteenth century, should be a consistent and reproducible anatomical concept. However, the current literature offers conflicting definitions of that scheme, not infrequently within a single article or monograph. The principal inconsistency found in modern publications concerns the termination of the V2 segment, which is either set at the C2 or C1 transverse foramen depending on the scheme considered. Consequently, the portion of the vertebral artery extending between C2 and C1-a frequent site of pathological involvement-either belongs to the V2 or V3 segment. This discrepancy can affect the validity of studies evaluating the diagnosis and management of vertebral artery disorders. A V3 segment extending from the transverse foramen of C2 to the posterior atlanto-occipital membrane and subdivided into vertical, horizontal, and oblique subsegments-a pattern suggested by Barbieri in 1867 and adopted in some modern publications-would provide a simple, precise, and reliable solution without significantly altering the widely accepted division of the vertebral artery into four segments (V1-V4).

Entrance and origin of the extracranial vertebral artery found on computed tomography angiography

To investigated morphological variability of vertebral artery (VA) origin and its entrance level into cervical transverse foramina by computed tomography angiography (CTA). To retrospectively investigated CTA of 223 subjects (446 VA courses). Investigated were origin of the VA and its level of entrance into vertebral transverse foramen with notification of the sex and side of variation. The VA entered the C6 transverse process in 91.70% of specimens (409 out of 446 VA courses). Abnormal entrance of VA was observed in 8.30% of specimens (37 VA courses), with the level of entrance into the C3, C4, C5, or C7 transverse foramen at 0.22%, 2.47%, 4.71% and 0.90% respectively. Comparably, the overall variability of abnormal origin of VA was 1.57% (7 out of 466 VA courses), in which the left vertebral arteries all arose from aortic arch. The variation rate of vertebral entrance rose up to 50% in abnormal origin subgroup. When comparing subgroups of subjects with normal and abnormal origin, there was significance difference in the frequency of entrance variation in the level of transverse foramen (p < 0.001). Abnormal entrance and origin of VA were observed in 8.30% and 1.57% of VA courses, which can be accurately appeared by CTA. Regarding to the subgroups of abnormal origin, the frequency of entrance variation was significantly increased in the level of transverse foramen compared to that of normal origin.

How to Identify Cervical Traumatic Neuromas in the Post-operative Neck Dissection: Brief Review of the Cervical Plexus Ultrasound

Cervical traumatic neuromas (CTNs) are a non-neoplastic hyperplasia of damaged nerves and may be misinterpreted as metastatic lymph nodes during cervical ultrasound of patients with thyroid cancer after lateral neck dissection, resulting in unnecessary and painful fin-needle aspiration biopsy. The anatomy of the cervical plexus is challenging, and the correct identification and recognition of its neural roots and branches on ultrasound are key to the correct CTN diagnosis. This review outlines the US technique used to characterize CTNs in 10 standardized steps and describes the sonographic features of the cervical plexus, to assist the radiologist in the recognition of CTNs and their differentiation from lymph node metastases.

MRI-Based Optimization Design of the Pre-Spinal Route of Contralateral C7 Nerve Transfer for Spastic Arm Paralysis

Purpose

The prespinal route of contralateral cervical 7 nerve transfer developed by Prof. Wendong Xu helps realize the direct anastomosis of the bilateral cervical 7 nerves. However, 20% of operations still require a nerve graft, which leads to an unfavorable prognosis. This study aims to explore the optimized prespinal route with MRI to further improve the prognosis.

Methods

The current study enrolled 30 patients who suffered from central spastic paralysis of an upper limb and who underwent contralateral cervical 7 nerve transfer via Prof. Xu’s prespinal route through the anterior edge of the contralateral longus colli. MRI images were used to analyze the route length, vertebral artery exposure, and contralateral cervical 7 nerve included angle. Three prespinal routes were virtually designed and analyzed. The selected optimal route was applied to another 50 patients with central spastic paralysis of an upper limb for contralateral cervical 7 nerve transfer.

Results

By the interventions on the 30 patients, the middle and posterior routes were shorter than the anterior route in length, but with no statistical difference between the two routes. Of 30 contralateral vertebral arteries, 26 were located at the posterior medial edge of the longus colli. The average included angles of the anterior, middle, and posterior routes were 108.02 ± 7.89°, 95.51 ± 6.52°, and 72.48 ± 4.65°, respectively. According to these data, the middle route was optimally applied to 50 patients, in whom the rate of nerve transplantation was only 4%, and no serious complications such as vertebral artery or brachial plexus injury occurred.

Conclusion

The low rate of nerve transplantation in 50 patients and the absence of any serious complications in these cases suggests that the middle route is the optimal one.

Morphometric Study of the Intracranial Segment of the Vertebral Artery

Background

The vertebral artery (VA) forms the caudal part of the circle of Willis and is responsible for one-third of the blood supply of the cerebellum, pons, middle ear, and the upper part of the spinal cord and its meninges. The highest potential risk of injury to VA during cervical pedicle screw implantation is at C3 and then at C6. Knowledge about the morphometry of VA provides a better understanding of clinical conditions such as vertebra basilar insufficiency (VBI). Similarly, the knowledge of variation in the VA is needed during cervical pedicle screw implantation, which possesses the highest potential risk to VA at the C3 level. The origin of the vertebral artery from the aortic arch reached the upper cervical vertebra than the vertebral artery of subclavian origin. The length of the VA is greater on the left side than the right-side artery. Understanding and reporting of the same are essential to creating awareness that can aid in endarterectomy, angioplasty, and radiological procedures. Variations are noted in morphometry between sides.

Aim

To determine the morphometry of the vertebral artery (VA) with emphasis on the fourth segment (V4) and its variations using computed tomography angiogram (CTA).

Materials and methods

This present retrospective study was conducted in the Departments of Anatomy and Radiology and Imaging Sciences, Saveetha Medical College and Hospital. Participants were patients who took a head and neck CT for various clinical reasons. About 50 CT images, 33 male and 17 females, were selected from the archives. The length, diameter, and entry level of VA were studied. The data were tabulated and statistically analyzed.

Result

The mean length of VA was 24.49 ± 3.02 (cm) on the left side and 24.28 ± 3.91 (cm) on the right side in female subjects and was found to be 22.78 ± 1.7 (cm) on the left side and 21.5 ± 2.7 (cm) on the right side in male subjects. The mean diameter of VA at the level of the foramen magnum was 0.32 ± 0.05 (cm) on the right side and 0.322 ± 0.07 (cm) on the left side in females, 0.3 ± 0.064 (cm) on the left side and 0.26 ± 0.086 (cm) on the right side in males.

Conclusion

The length of VA was found to be statistically more on the left side than on the right side. The variations in morphometry seen can aid in various surgical and radiological procedures.

Iatrogenic Vascular Injury Associated with Cervical Spine Surgery: A Systematic Literature Review

BACKGROUND

Iatrogenic vascular injury is an uncommon complication of anterior and/or posterior surgical approaches to the cervical spine. Although the results of this injury may be life-threatening, mortality/morbidity can be reduced by an understanding of its mechanism and proper management.

METHODS

We conducted a literature review to provide an update of this devastating complication in spine surgery. A total of 72 articles including 194 cases of vascular lesions following cervical spine surgery between 1962 and 2021 were analyzed.

RESULTS

There were 53 female and 41 male cases (in addition to 100 cases with unreported sex) with ages ranging from 3 to 86 years. The vascular injuries were classified according to the spinal procedures, such as anterior or posterior cervical spine surgery. The interval between the symptom of the vascular injury and the surgical procedure ranged from 0 to 10 years. Only two-thirds of patients underwent intra- or postoperative imaging and the most frequently injured vessel was the vertebral artery (86.60%). Laceration was the most common lesion (41.24%), followed by pseudoaneurysm (16.49%) and dissection (5.67%). Vascular repair was performed in 114 patients. The mortality rate was 7.22%, and 18.04% of patients had 1 or more other complications. Most presumed causes of vascular lesions were by instrumentation/screw placement (31.44%) or drilling (20.61%). Sixteen patients had an anomalous artery. Direct microsurgical repair was achieved in only 15 cases.

CONCLUSIONS

Despite increased anatomical knowledge and advanced imaging techniques, we need to consider the risk of vascular injury as a surgical complication in patients with cervical spine pathologies.

Cervical Spine Navigation and Enabled Robotics: A New Frontier in Minimally Invasive Surgery

Background: Robotic-assisted and computer-assisted navigation (CAN) systems utilization has been rapidly increasing in recent years. Most existing data using these systems are performed in the thoracic, lumbar, and sacral spine. The unique anatomy of the cervical spine maybe where these technologies have the greatest potential. To date, the role of navigation-enabled robotics in the cervical spine remains in its early stages of development and study. Purpose: This review article describes the early experience, case descriptions and technical considerations with cervical spine screw fixation and decompression using CAN and robotic-assisted surgery. Methods: Representative cervical cases with early surgical experience with cervical and robotic assisted surgery with CAN. Surgical set up, technique considerations, instrumentation, screw accuracy and screw placement were elevated and recorded for each representative cervical case. Results: Existing robotic assisted spine surgical systems are reviewed as they pertain to the cervical spine. Method for cervical reference and positioning on radiolucent Mayfield tongs are presented. C1 lateral mass, odontoid fracture fixation, C2 pedicle, translaminar, subaxial lateral mass, mid cervical pedicle, navigated decompression and ACDF cases and techniques are presented. Conclusion: In conclusion, within the last several years, the use of CANs in spinal surgery has grown and the cervical spine shows the greatest potential. Several robotic systems have had FDA clearance for use in the spine, but such use requires simultaneous intraoperative fluoroscopic confirmation. In the coming years, this recommendation will likely be dropped as accuracy improves.

High-Entry Vertebral Artery Variant during Anterior Cervical Discectomy and Fusion

Anterior surgical approaches to the cervical spine have allowed for treatment of common and complex pathologies with excellent outcomes. During the approach, complications can result from injury to the surrounding structures. The transverse processes usually protect the vertebral artery (VA) as it enters at C6 and courses cranially through the transverse foramina to C2 (referred to as the V2 segment). This is a case report of a patient who presented with myeloradiculopathy attributed to a C4-C5 disc herniation, severe canal stenosis, and marked bilateral neural foraminal stenosis. Preoperative imaging showed the right VA entering the C4 transverse foramen. This anatomic variant on a routine MRI led to further imaging and precautions when performing an uneventful anterior cervical discectomy and fusion (ACDF) at C4-C5. A high VA entry point into the transverse foramen above C6 could increase the risk of iatrogenic vascular injury in anterior approaches to the cervical spine. Rarely reported, the currently presented case describes a patient with a C4 right VA entry variant and highlights the importance of proper surgical planning.

Evaluation of tortuous vertebral arteries before cervical spine surgery: illustrative case

BACKGROUND

Cervical spine surgery sometimes necessitates complex ventral/dorsal approaches or osteotomies that place the vertebral artery (VA) at risk of inadvertent injury. Tortuosity of the VA poses increased risk of vessel injury during anterior decompression or placement of posterior instrumentation.

OBSERVATIONS

In this report, the authors describe a patient with degenerative cervical spondylotic myelopathy and focal kyphotic deformity requiring corrective surgery via a combined ventral/dorsal approach. Computed tomography (CT) and CT angiography (CTA) of the spine identified a left medially enlarged C4 transverse foramen and tortuous VA V2 segment forming a potentially dangerous medial loop into the vertebral body, respectively. The patient’s presentation and management are described.

LESSONS

The course of the VA is variable, and a tortuous VA with significant medial or lateral displacement may be dangerous during ventral and dorsal approaches to the cervical spine. CTA of the cervical spine is warranted in cases in which atlantoaxial fixation is needed or suspicious transverse foramen morphology is identified to understand the course of the VA and identify anatomical variations that would put the VA at risk during cervical spine surgery.

First reported use of real-time intraoperative computed tomography angiography image registration using the Machine-vision Image Guided Surgery system: illustrative case

BACKGROUND

Vertebral artery injury is a devastating potential complication of C1–2 posterior fusion. Intraoperative navigation can reduce the risk of neurovascular complications and improve screw placement accuracy. However, the use of intraoperative computed tomography (CT) increases radiation exposure and operative time, and it is unable to image vascular structures. The Machine-vision Image Guided Surgery (MvIGS) system uses optical topographic imaging and machine vision software to rapidly register using preoperative imaging. The authors presented the first report of intraoperative navigation with MvIGS registered using a preoperative CT angiogram (CTA) during C1–2 posterior fusion.

OBSERVATIONS

MvIGS can register in seconds, minimizing operative time with no additional radiation exposure. Furthermore, surgeons can better adjust for abnormal vertebral artery anatomy and increase procedure safety.

LESSONS

CTA-guided navigation generated a three-dimensional reconstruction of cervical spine anatomy that assisted surgeons during the procedure. Although further study is needed, the use of intraoperative MvIGS may reduce the risk of vertebral artery injury during C1–2 posterior fusion.

Morphologic Changes in the Vertebral Artery Subsequent to Cervical Spine Degeneration and Aging: Analyses by Computed Tomography Angiography Using Multiplanar and 3-Dimensional Reconstructions

OBJECTIVE

To identify the morphologic changes in the vertebral artery (VA) subsequent to cervical spine degeneration and aging and to investigate the risk factors for iatrogenic VA injury or occlusion.

METHODS

Eighty-eight consecutive patients (176 bilateral VAs) were retrospectively analyzed using radiographs, computed tomography, and computed tomography angiography images. The Kellgren and Lawrence (KL) score and its modified subscores were used to grade the severity of degenerative changes in the cervical spine. VA tortuosity widths and diameters were measured between the C2 and C6 transverse foramens. The outcome measures were statistically analyzed for difference, correlation, and explanatory variable. The level with a high prevalence of VA stenosis was also evaluated.

RESULTS

There were significant positive correlations between the KL score and VA tortuosity width, and between age and VA tortuosity width. Osteophyte formation in the facet joint was the predominant explanatory variable for medial deviation of the VA. Significant positive correlations were evident between the dominant VA diameter and KL score or age. VA stenosis occurred at C3/C4 (24.5%) with the highest prevalence and it was caused by uncovertebral joint osteophytes (52.0%) with the highest incidence.

CONCLUSIONS

The present study provides important evidence for decisions of surgical strategy and for avoiding catastrophic VA injury or occlusion in cervical spine surgeries.

Vertebral Artery Mobilization and Cervical Tumor Resection

BACKGROUND

To emphasize the importance of vertebral artery (VA) mobilization by reviewing the anatomy and variations of the VA while performing total resection of VA-associated tumors that develop from different tissues.

METHODS

VA mobilization and mass resection were performed after the evaluation and preoperative imaging of 22 patients with VA-related tumors. Anterior, posterior, or both approaches were conducted on the patients and stabilization was also applied to the patients in need. Radiotherapy and/or chemotherapy were planned for patients with malignant tumors as shown by histopathology.

RESULTS

Overall, 17 patients with benign and 5 patients with malignant tumors underwent tumor resection with VA mobilizing. There were 13 male and 9 female patients with a mean age of 29.3 years. The average follow-up duration was 53 months. All the patients received gross total tumor resection and had a good postoperative neurological recovery. No complications were observed; local recurrence was observed only in 2 patients.

CONCLUSIONS

VA mobilization reduces the need for instrumentation in VA-related cases, especially nerve tumors, and increases the possibility of the surgical resection of vertebral tumors.

Intraoperative surveillance of the vertebral artery using indocyanine green angiography and Doppler sonography in craniovertebral junction surgeries

OBJECTIVE

The authors sought to evaluate the usefulness of indocyanine green (ICG) angiography and Doppler sonography for monitoring the vertebral artery (VA) during craniovertebral junction (CVJ) surgery and compare the incidence of VA injury (VAI) between the groups with and without the monitoring of VA using ICG angiography and Doppler sonography.

METHODS

In total, 344 consecutive patients enrolled who underwent CVJ surgery. Surgery was performed without intraoperative VA monitoring tools in 262 cases (control group) and with VA monitoring tools in 82 cases (monitoring group). The authors compared the incidence of VAI between groups. The procedure times of ICG angiography, change of VA flow velocity measured by Doppler sonography, and complication were investigated.

RESULTS

There were 4 VAI cases in the control group, and the incidence of VAI was 1.5%. Meanwhile, there were no VAI cases in the monitoring group. The procedure time of ICG angiography was less than 5 minutes (mean [± SD] 4.6 ± 2.1 minutes) and VA flow velocity was 11.2 ± 4.5 cm/sec. There were several cases in which the surgical method had to be changed depending on the VA monitoring. The combined use of ICG angiography and Doppler sonography was useful not only to monitor VA patency but also to assess the quality of blood flow during CVJ surgery, especially in the high-risk group of patients.

CONCLUSIONS

The combined use of ICG angiography and Doppler sonography enables real-time intraoperative monitoring of the VA by detecting blood flow and flow velocity. As the arteries get closer, they provide auditory and visual feedback to the surgeon. This real-time image guidance could be a useful tool, especially for high-risk patients and inexperienced surgeons, to avoid iatrogenic VAI during any CVJ surgery.

Atypical Course of Vertebral Artery Outside the Cervical Spine: Case Report and Review of the Literature

BACKGROUND

The vertebral arteries are branches of the subclavian arteries supply blood to the posterior part of the encephalon, forming vertebrobasilar circulation. Disorders of vertebrobasilar circulation have significant clinical implications. Symptoms of these disorders include dizziness, vomiting, collapse, vision and cerebellar disorders. The vertebral artery usually ascends in the transverse foramina of the cervical vertebrae to reach the posterior cranial cavity by entering the magnum foramen. Although most often the vertebral artery enters the C6 transverse process, anatomic variation may occur.

CASE DESCRIPTION

In this case, a 16-year-old male patient with casuistic anatomic variant of vertebral artery course is described. In this case report, left vertebral artery ascended outside the transverse foramina of cervical vertebrae C6-C3 and entered transverse foramen of axis. The patient suffered from collapse and dizziness during neck and head movements as a result of arterial folding. After rehabilitation and posture and proper movement learning, the frequency of symptoms subsided.

CONCLUSIONS

Variability of the vertebral arteries may have clinical implications, and knowledge of its topography is important for mechanism of vertebrobasilar circulatory disorder understanding and for surgical approach to the cervical spine and neck anatomic structures.

Extraforaminal Vertebral Artery Anomalies and Their Associated Surgical Implications: An Epidemiologic and Anatomic Report on 1000 Patients

OBJECTIVE

Extraforaminal vertebral anomalies involve entry at cervical transverse foramina other than at C6 and can appear with other anatomic variations along the V2 segment. Such unexpected vessel courses can have implications on surgical planning. We sought to evaluate the incidence of anomalous V2 segment entries, as well as their associations with vessel dominance, medialization, and C7 pedicle width.

METHODS

We conducted a retrospective study on 1000 consecutive computed tomography angiograms, documenting level and laterality of vessel of entry, as well as vertebral dominance patterns. Patients with rostral C4 anomalies were assessed for medialization. The pedicle widths ipsilateral to caudal C7 anomalies were compared with those of contralateral and matched controls.

RESULTS

A total of 157 patients were identified with extraforaminal entries, with 25 having bilateral findings. The most common alternative entry was at C5 (70.3%), followed by C4 (17.6%) and C7 (11.5%). Among patients with unilateral anomalies, there was an increased representation of contralateral vertebral dominance, relative to ipsilateral dominance (79.6% vs 20.4%, P < 0.0001). Among anomalous C4 entries, vertebral medialization was seen along the right (35%) and left sides (23.1%) spanning C6-T1. Among C7 anomalous entries there was no statistical difference in pedicle width.

CONCLUSIONS

Extraforaminal anomalies may be more frequent than previously reported and are important considerations during subaxial cervical spine surgery planning. Particular attention should be paid to the contralateral dominance pattern within this subgroup. In patients with anomalous V2 segment entries, adherence to the standard, anatomic landmarks remains desirable.

A Novel and Reproducible Classification of the Vertebral Artery in the Subaxial Cervical Spine

BACKGROUND

An injury of the vertebral artery (VA) is one of the most catastrophic complications in the setting of cervical spine surgery. Anatomic variations of the VA can increase the risk of iatrogenic lacerations.

OBJECTIVE

To propose a novel and reproducible classification system that describes the position of the VA based on a 2-dimensional map on computed tomography angiographs (CTA).

METHODS

This cross-sectional retrospective study reviewed 248 consecutive CTAs of the cervical spine at a single academic institution between 2007 and 2018. The classification consists of a number that characterizes the location of the VA from the medio-lateral (ML) aspect of the vertebral body. In addition, a letter describes the VA location from the anterior-posterior (AP) aspect. The reliability and reproducibility were assessed by 2 independent raters on 200 VAs.

RESULTS

The inter- and intrarater reliability values showed the classification's reproducibility. The inter-rater reliability weighted κ-value for the ML aspect was 0.93 (95% CI: 0.93-0.93). The unweighted κ-value was 0.93 (95% CI: 0.86-1.00) for "at-risk" positions (ML grade ≥1), and 0.87 (95% CI: 0.75-1.00) for "high-risk" positions (ML grade ≥2). The weighted κ-value for the intrarater reliability was 0.94 (95% CI: 0.95-0.95). The unweighted κ-values for the intrarater reliability were 0.95 (95% CI: 0.91-0.99) for "at-risk" positions, and 0.87 (95% CI: 0.78-0.96) for "high-risk" positions.

CONCLUSION

The proposed classification is reliable, reproducible, and independent of individual anatomic size variations. The use of this novel grading system could improve the understanding and interdisciplinary communication about VA anomalies.

Is the Vertebral Posterior Line a Safety Landmark for Cervical Posterior Screw Insertion? - Radiological Study of the Vertebral Artery in the Cervical Spine

At posterior cervical fixation, iatrogenic injury of the vertebral artery (VA) must be avoided. As the VA is usually located in front of the posterior line of the vertebral body, intraoperative lateral fluoroscopy is used to identify the line. We investigated in how many of 105 patients (210 VAs) this line is a safe marker. We also inspected the original cervical magnetic resonance angiograms (MRA) of 105 consecutive patients who had been treated for other than cervical spine diseases to study some anatomical characteristics of the VA in the cervical spine. The distance from the posterior line of the vertebral body to the posterior VA surface was classified as safe, as requiring attention, and as unsafe. Among the 210 VAs, four hypoplastic vessels were excluded from this study; consequently, 206 VAs were available for assessment. The average distance exceeded 6 mm, it was shorter at the upper cervical level. Although in at least 200 VAs (97.1%) the distance between C4 and C7 was safe, in only 170 VAs (82.5%) was it safe at C3. We observed a total of 31 tortuous loops in 17 VAs; their presence had a significant negative effect on the usefulness of the safety line. Although the posterior line of the vertebral body may be useful for safe screw insertion at the C4-C7 level, it may be less useful at C3. In the presence of tortuous VA loops, close attention must be paid to the reliability of the safety line during cervical spine surgery.

Transdiscal C7 Pedicle Subtraction Osteotomy With a Strut Graft and the Correction of Sagittal and Coronal Imbalance of the Cervical Spine

BACKGROUND

Cervical spine deformity negatively affects patients' quality of life. Pedicle subtraction osteotomy (PSO) has reported to correct cervical deformity but it is challenging and carries a significant risk of morbidity.

OBJECTIVE

To report transdiscal C7 PSO with a strut graft for the correction of sagittal and coronal imbalance in patients with fixed cervical deformity.

METHODS

After standard exposure, the spine was instrumented from C2 to T3. T1 subtotal laminectomy, and C6 to C7 total laminectomies were necessary for C7 PSO. Osteotomy was initiated with removal of C6-7 and C7-T1 facet joints to isolate C7 pedicles and identify bilateral C7/C8 roots. Bilateral C7 pediculectomies and transdiscal PSO were performed. A rectangular strut allograft was then inserted into the PSO site. The location of the strut graft was used as a fulcrum of sagittal and coronal correction. The head fixator was released and the head was extended under intraoperative neuromonitoring, and then detailed sagittal and coronal balances were controlled by compressing or distracting between the pedicle screws above and below the osteotomy.

RESULTS

This technique was applied in 2 patients with fixed subaxial cervical deformities. Transdiscal PSO could add more amount of correction and provide the additional fusion surface. The strut graft prevented sagittal translation, foraminal narrowing, and excessive focal cord kinking during PSO. Both patients showed radiologic and clinical improvements after surgery, and no neurovascular complication occurred after the surgery.

CONCLUSION

Transdiscal C7 PSO with a strut graft placement provided a safe way of correcting sagittal and coronal imbalance simultaneously and reduced neurological complication by preventing sagittal translation, foraminal narrowing and spinal cord kinking.

The case for T2 pedicle subtraction osteotomy in the surgical treatment of rigid cervicothoracic deformity

OBJECTIVE

Rigid cervicothoracic kyphotic deformity (CTKD) remains a difficult pathology to treat, especially in the setting of prior cervical instrumentation and fusion. CTKD may result in chronic neck pain, difficulty maintaining horizontal gaze, and myelopathy. Prior studies have advocated for the use of C7 or T1 pedicle subtraction osteotomies (PSOs). However, these surgeries are fraught with danger and, most significantly, place the C7, C8, and/or T1 nerve roots at risk.

METHODS

The authors retrospectively reviewed their experience with performing T2 PSO for the correction of rigid CTKD. Demographics collected included age, sex, details of prior cervical surgery, and coexisting conditions. Perioperative variables included levels decompressed, levels instrumented, estimated blood loss, length of surgery, length of stay, complications from surgery, and length of follow-up. Radiographic measurements included C2-7 sagittal vertical axis (SVA) correction, and changes in the cervicothoracic Cobb angle, lumbar lordosis, and C2-S1 SVA.

RESULTS

Four male patients were identified (age range 55-72 years). Three patients had undergone prior posterior cervical laminectomy and instrumented fusion and developed postsurgical kyphosis. All patients underwent T2 PSO: 2 patients received instrumentation at C2-T4, and 2 patients received instrumentation at C2-T5. The median C2-7 SVA correction was 3.85 cm (range 2.9-5.3 cm). The sagittal Cobb angle correction ranged from 27.8° to 37.6°. Notably, there were no neurological complications.

CONCLUSIONS

T2 PSO is a powerful correction technique for the treatment of rigid CTKD. Compared with C7 or T1 PSO, there is decreased risk of injury to intrinsic hand muscle innervators, and there is virtually no risk of vertebral artery injury. Laminectomy may also be safer, as there is less (or no) scar tissue from prior surgeries. Correction at this distal level may allow for a greater sagittal correction. The authors are optimistic that these findings will be corroborated in larger cohorts examining this challenging clinical entity.

Comparison of ultrasound-guided stellate ganglion block at 6th and 7th cervical vertebrae using the lateral paracarotid out-of-plane approach for sympathetic blockade in the upper extremity

Background

The authors have performed ultrasound-guided stellate ganglion block (SGB) in our clinic using a lateral paracarotid approach at the level of the 6th cervical vertebra (C6). Although SGB at C6 is a convenient and safe method, there are ongoing concerns about the weak effect of sympathetic blockade in the ipsilateral upper extremity. Therefore, ultrasound-guided SGB was attempted using a lateral paracarotid approach at the level of the 7th cervical vertebra (C7). This prospective study aimed to compare changes in skin temperature after SGB was performed at C6 and C7, and to introduce a lateral paracarotid approach for SGB.

Methods

Thirty patients underwent SGB twice: once at C6 and once at C7. For every SGB, the skin temperature of the patient’s hypothenar area was measured for 15 min at 1-min intervals. Skin temperatures before and after SGB and side effects were compared between C6 and C7 groups.

Results

The temperature of the upper extremity increased after SGB was performed at C6 and C7. There were significant differences between mean pre-SGB and the largest increases in post-SGB temperatures (0.50±0.38℃ and 1.41±0.68℃ at C6 and C7, respectively; p<0.05). Significantly increased post-SGB temperatures (difference >1℃) were found in 5/30 (16.7%) and 24/30 (80%) cases for C6 and C7, respectively (p<0.05). There were no significant differences in side effects between SGB performed at C6 or C7 (p>0.05).

Conclusion

The lateral paracarotid approach using out-of-plane needle insertion for ultrasound-guided SGB performed at C7 was feasible and more effective at elevating skin temperature in the upper extremity than SGB at C6.

A Review of the Historical Evolution, Biomechanical Advantage, Clinical Applications, and Safe Insertion Techniques of Cervical Pedicle Screw Fixation

Cervical spine instrumentation is evolving with an aim of stabilizing traumatic and non-traumatic cases of the cervical spine with a beneficial reduction, better biomechanical strength, and a strong construct with minimal intraoperative, as well as immediate and late postoperative complications. The evolution from interspinous wiring till cervical pedicle screws has changed the outlook in treating the cervical spine pathologies with maximum 3D stability, decreasing the duration of postoperative immobilization and hospital stay. Some complications associated with the use of cervical pedicle screw can be catastrophic. This review article discusses the morphometry of cervical pedicle; indications, biomechanical superiority, tricks, and pitfalls of cervical pedicle screw; complications and technical advancements in targeting safe surgery; and future directions of cervical pedicle screw instrumentation.

Anatomical Relationship of the Vertebral Artery With the Lateral Recess: Clinical Importance for Posterior Cervical Foraminotomy

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.

Are the anomalous vertebral arteries more hypoplastic?: retrospective linear mixed model approach

Background

Small or hypoplastic vertebral artery (VA) is one of the risk factor for posterior circulation stroke. We assess whether various types of VA anomaly contribute to its diameter.

Methods

We screened 238 patients who underwent neck CT and MR angiography within 1 month. A V1 anomaly was defined as the abnormal origin of the VA on a three-dimensional MR angiography and a V2 anomaly was defined as the VA not passing through the 6th cervical transverse foramen (TF) on an axial CT image. A linear mixed model was used to evaluate the determinants of VA size.

Results

Among participants, 24 (10.1%) subjects exhibited an anomalous VA and, of the 476 VAs examined, 11 (2.3%) had an aortic origin and 27 (5.7%) had an abnormal entrance into the C6 TF. Presence of the V1 anomaly was positively associated with the V2 anomaly (P for chi-square < 0.001) and a linear mixed model revealed that being male (0.2 mm larger, P = 0.015), having a right VA anomaly (0.3 mm smaller, P < 0.001), having a V1 anomaly (0.9 mm smaller, P < 0.001), and having a V2 anomaly (0.7 mm smaller, P < 0.001) were significant predictor of VA diameter.

Conclusion

The diameters of VAs with an anomalous aortic origin or an abnormal entrance of the TF were significantly smaller than those of normal VAs. These findings suggest that anomalies of the VA detected in 3-dimensional CTA or MRA may be clues for vertebral artery hypoplasia.

Electronic supplementary material

The online version of this article (10.1186/s12883-017-0951-x) contains supplementary material, which is available to authorized users.

Iatrogenic Vertebral Artery Injury During Anterior Cervical Spine Surgery: A Systematic Review

BACKGROUND

Iatrogenic vertebral artery injury (VAI) during anterior cervical surgery is rare but potentially catastrophic.

METHODS

Causes, presentation, diagnosis, management, prognosis, and prevention of VAI were reviewed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. English language studies and case reports published from 1980 to 2017 were retrieved. Data on diagnosis, surgical procedures and approach, site and cause of VAI, management, outcomes, and vertebral artery (VA) status were extracted.

RESULTS

In 25 articles including 54 patients, VAI was diagnosed during or after surgery commonly indicated for cervical degenerative diseases (64%), tumors (14%), and trauma (9%). The incidence of VAI for each side was similar regardless of approach. Common presentations were unexpected copious surgical bleeding, delayed hemorrhage of pseudoaneurysm with neck swelling, dyspnea, hypotension, and cervical bruits caused by arteriovenous fistula. Causes included drilling (61%), instrumentation (16%), and soft tissue retraction (8%). Direct exposure or angiography confirmed VAI. Ten patients had VA anomalies; collateral status was verified in 9 before definitive treatment. Tamponade was adopted for urgent hemostasis in most cases but with a high incidence of pseudoaneurysm (48%). Unknown VA status increased occlusion risk and neurologic sequelae (41%). VA repair and stent placement had excellent outcomes.

CONCLUSIONS

Extensive lateral decompression, loss of landmarks, and anatomic variations or pathologic status of VA increased VAI risk. Evaluation of collateral vessels before definitive treatment helped determine appropriate management and avoid neurologic sequelae. Tamponade was not recommended as definitive treatment. Meticulous preoperative evaluation, cautious intraoperative manipulation, and real-time radiographic guidance reduced VAI risk.

Aortic arch origin of the left vertebral artery: An Anatomical and Radiological Study with Significance for Avoiding Complications with Anterior Approaches to the Cervical Spine

Complications from anterior approaches to the cervical spine are uncommon with normal anatomy. However, variant anatomy might predispose one to an increased incidence of injury during such procedures. We hypothesized that left vertebral arteries that arise from the aortic arch instead of the subclavian artery might take a more medial path in their ascent making them more susceptible to iatrogenic injury. Fifty human adult cadavers were examined for left vertebral arteries having an aortic arch origin and these were dissected along their entire cervical course. Additionally, two radiological databases of CTA and arteriography procedures were retrospectively examined for cases of aberrant left vertebral artery origin from the aortic arch over a two-year period. Two cadaveric specimens (4%) were found to have a left vertebral artery arising from the aortic arch. The retrospective radiological database analysis identified 13 cases (0.87%) of left vertebral artery origin from the aortic arch. Of all cases, vertebral arteries that arose from the aortic arch were much more likely to not only have a more medial course (especially their preforaminal segment) over the cervical vertebral bodies but also to enter a transverse foramen that was more cranially located than the normal C6 entrance of the vertebral artery. Spine surgeons who approach the anterior cervical spine should be aware that an aortic origin of the left vertebral artery is likely to be closer to the midline and less protected above the C6 vertebral level. Clin. Anat. 30:811-816, 2017. © 2017Wiley Periodicals, Inc.

A lateral paracarotid approach for ultrasound-guided stellate ganglion block with a linear probe

Recent reports suggest that ultrasound-guided stellate ganglion block (SGB) is safer and more accurate than classic SGB by the using the surface anatomical landmark. However, previous reports concern the classic paratracheal approach using a small specialized curved probe, which may not be appropriate in some patients. The authors have attempted several approaches, including paratracheal, trans-thyroidal, lateral paracarotid, and lateral approaches, to find a safe and suitable method for real-time ultrasound-guided SGB using a standard high-frequency linear probe. A total of 27 injections were performed on 27 patients with sensorineural hearing loss. The lateral paracarotid out-of-plane and lateral in-plane approaches were identified as the easiest and safest methods among the four tested. In this report, we describe a new lateral paracarotid approach for ultrasound-guided SGB. An ipsilateral paratracheal short-axis transverse scan was acquired at the C6 level with a linear probe (6-13 MHz). The probe was moved laterally, scanning the thyroid, carotid artery, internal jugular vein, longus colli muscle, and the transverse process of the C6, placing the carotid artery in the middle of the view. Light pressure was applied to the probe postero-medially to displace the carotid artery medially and completely compress the internal jugular vein. The needle was inserted out-of-plane between the lateral margin of the carotid artery and Chassaignac's tubercle, traversing the collapsed internal jugular vein, and targeted between the longus colli muscle and the prevertebral fascia. A total of 4 ml of 0.2% ropivacaine was injected for each procedure after a negative aspiration test. Successful blockade was confirmed with the onset of Horner's sign. All 27 injections resulted in successful blockade with Horner's sign presenting within 5 min after injection. Side effects were minor and caused minimal discomfort; they included hoarseness and a foreign body sensation. No hematomas formed after any injections. We suggest that this new lateral paracarotid approach, with out-of plane needle insertion at the C6 tubercle under transverse scan, is a convenient and safe method for performing real-time ultrasound-guided SGB, as it provides a wide, safe space for needle passage without risking thyroid or esophageal injury.

Epidemiology and Outcomes of Vertebral Artery Injury in 16 582 Cervical Spine Surgery Patients: An AOSpine North America Multicenter Study

STUDY DESIGN

A multicenter retrospective case series was compiled involving 21 medical institutions. Inclusion criteria included patients who underwent cervical spine surgery between 2005 and 2011 and who sustained a vertebral artery injury (VAI).

OBJECTIVE

To report the frequency, risk factors, outcomes, and management goals of VAI in patients who have undergone cervical spine surgery.

METHODS

Patients were evaluated on the basis of condition-specific functional status using the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) score, the Nurick scale, and the 36-Item Short-Form Health Survey (SF-36).

RESULTS

VAIs were identified in a total of 14 of 16 582 patients screened (8.4 per 10 000). The mean age of patients with VAI was 59 years (±10) with a female predominance (78.6%). Patient diagnoses included myelopathy, radiculopathy, cervical instability, and metastatic disease. VAI was associated with substantial blood loss (770 mL), although only 3 cases required transfusion. Of the 14 cases, 7 occurred with an anterior-only approach, 3 cases with posterior-only approach, and 4 during circumferential approach. Fifty percent of cases of VAI with available preoperative imaging revealed anomalous vessel anatomy during postoperative review. Average length of hospital stay was 10 days (±8). Notably, 13 of the 14 (92.86%) cases resolved without residual deficits. Compared to preoperative baseline NDI, Nurick, mJOA, and SF-36 scores for these patients, there were no observed changes after surgery (P = .20-.94).

CONCLUSIONS

Vertebral artery injuries are potentially catastrophic complications that can be sustained from anterior or posterior cervical spine approaches. The data from this study suggest that with proper steps to ensure hemostasis, patients recover function at a high rate and do not exhibit residual deficits.

Carotid ultrasound features of anomalous left vertebral artery originating from the aortic arch proximal to the left subclavian artery

We present three cases of anomalous origin of the left vertebral artery (LVA) detected during the evaluation of stroke. The VA usually enters the transverse foramen of the sixth cervical vertebra (C6), but an anomalous LVA originating from the aorta frequently enters at a higher level. In our series, ultrasound of the LVA showed entry at C4 in two patients and at C5 in one patient. These findings suggested anomalous LVA origin, and three-dimensional computed tomography demonstrated the LVA arising from the aorta proximal to the left subclavian arteries. Carotid duplex ultrasound is useful for the diagnosis of this anomaly.

Treatment of Basilar Invagination With Klippel-Feil Syndrome: Atlantoaxial Joint Distraction and Fixation With Transoral Atlantoaxial Reduction Plate

BACKGROUND

Klippel-Feil syndrome (KFS) is characterized by congenital vertebral fusion of the cervical spine and a wide spectrum of associated anomalies. In patients with KFS with basilar invagination (BI), compression of the brainstem and upper cervical cord results in neurological deficits, and decompression and occipitocervical reconstruction are required. The highly varied anatomy of KFS makes a posterior occipitocervical fixation strategy challenging. For these patients, the transoral atlantoaxial reduction plate (TARP) operation is an optimal option to perform a direct anterior fixation to achieve stabilization.

OBJECTIVE

To evaluate the effectiveness of TARP internal fixation for the treatment of BI with KFS.

METHODS

Ten consecutive patients with BI and KFS who underwent TARP reduction and fixation from 2010 to 2012 were reviewed. Clinical assessment and image measurements were performed preoperatively and at the most recent follow-up. Nine patients (9/10) were followed for an average of 31.44 months.

RESULTS

Symptoms were alleviated in 9 of 9 patients (100.00%). The odontoid process was ideally corrected with the TARP system. The mean clivus canal angle improved from 124° preoperatively to 152° postoperatively. The average preoperative and postoperative Japanese Orthopedic Association scores were 10.56 (n = 9) and 14.67 (n = 9), respectively, indicating 63.82% improvement. There was bony bridge catenation on the computed tomography scans and no evidence of hardware failure at 6 months.

CONCLUSION

The TARP operation is effective and safe for treating patients with BI with KFS. The midterm clinical results were satisfactory.

Vertebral artery loops in surgical perspective

PURPOSE

Vertebral artery loop is a congenital or acquired anomaly. Vertebral artery loops are incidentally diagnosed during evaluation of neck problems and trauma. We aimed to present the incidence of VA loops using magnetic resonance angiography in consecutive patients and discuss epidemiological data including the gender, age, location, signs and symptoms, treatment approaches and outcomes of VA loops via analyzing literature.

METHODS

In the first leg of our two-legged study, consecutive patients were evaluated using magnetic resonance angiography to detect any medial loop of vertebral arteries. The study period was from October 2015 to March 2016. In the second leg, academic databases about medial loop of vertebral artery were screened. Case reports, case series, abstracts and references of relevant literature were searched manually to avoid any missing cases.

RESULTS

We evaluated 239 consecutive patients using magnetic resonance angiography. Twenty-one patients were excluded from the study due to inadequate image acquisition, aplastic vertebral artery and/or concomitant vertebral artery stenosis. Medial loop of V2 vertebral artery was observed in 13 patients (5.9 %): 9 with left, 2 with right and 2 with bilateral medial V2 loop. Patients with medial V2 loop were significantly older than patients with straight vertebral arteries (70.30 vs. 62.36, p = 0.028). In the literature analysis, VA loops were more commonly observed at V2 segment (90.5 %). Vertebral artery loops were mostly diagnosed at the 5th and 6th decades of life predominantly in females. The most common signs and symptoms were radiculopathy and/or neck pain, and signs and symptoms of vertebrobasilar insufficiency.

CONCLUSIONS

Concise pre-operative evaluation of the vertebral arteries is essential to avoid the injury of undiagnosed VA loops during surgery, which might result in catastrophic circumstances. Further evaluation of the vertebral arteries using MR angiography is required, especially in elder age, before cervical spine surgeries.

Surgical Anatomy of the Longus Colli Muscle and Uncinate Process in the Cervical Spine

PURPOSE

There have been a few previous reports regarding the distances between the medial borders of the longus colli to expose the disc space. However, to our knowledge, there are no reports concerning longus colli dissection to expose the uncinate processes. This study was undertaken to assess the surgical relationship between the longus colli muscle and the uncinate process in the cervical spine.

MATERIALS AND METHODS

This study included 120 Korean patients randomly selected from 333 who had cervical spine MRIs and CTs from January 2003 to October 2013. They consisted of 60 males and 60 females. Each group was subdivided into six groups by age from 20 to 70 years or more. We measured three parameters on MRIs from C3 to T1: left and right longus colli distance and inter-longus colli distance. We also measured three parameters on CT: left and right uncinate distance and inter-uncinate distance.

RESULTS

The longus colli distances, uncinate distances, and inter-uncinate distances increased from C3 to T1. The inter-longus colli distances increased from C3 to C7. There was no difference in longus colli distances and uncinate distances between males and females. There was no difference in the six parameters for the different age groups.

CONCLUSION

Although approximate guidelines, we recommend the longus colli be dissected approximately 5 mm at C3-5, 6 mm at C5-6, 7 mm at C6-7, and 8 mm at C7-T1 to expose the uncinate process to its lateral edge.

Intraspinal migration of a Kirschner wire as a late complication of acromioclavicular joint repair: a case report

BACKGROUND

Penetrating neck trauma involving foreign bodies is a rare event in European countries. Due to its relatively high mortality rate, the correct management strategy must be initiated from the beginning to prevent fatal complications. In the medical literature, there are only a few cases describing foreign bodies penetrating the cervical spine. Because of its rareness, many trauma centers lack the proper routine to adequately manage such injuries.

CASE PRESENTATION

This case report describes a 34-year-old white man of Central European descent with Kirschner wire migration and perforation of his vertebral foramen. He underwent acromioclavicular joint repair surgery 7 years ago, presented with a painful sensation around the area of his left clavicle and left side of his neck after a motorcycle accident. No neurological deficit was detected.

CONCLUSIONS

In such cases, a thorough radiological evaluation of the spinal cord and the surrounding vasculature is mandatory for a complete understanding of the extent of the injury and determining the proper surgical management. In cases of vertebral artery trauma both an endovascular and an open approach can be contemplated.

Prevalence of C7 level anomalies at the C7 level: an important landmark for cervical nerve ultrasonography

BACKGROUND

Recently, various examination and intervention techniques using cervical nerve ultrasonography have been developed. The specific shapes of the C7 transverse process and vertebral artery in front of the C7 transverse process have become landmarks.

PURPOSE

To determine the prevalence of anomalies and anomalous vertebral artery entrances at the C7 transverse process.

MATERIAL AND METHODS

The records of patients who underwent plain or contrast-enhanced neck or cervical spine computed tomography (CT) were reviewed. The examinations were scored for the anomalous presence of anterior tubercles or cervical ribs as well as vertebral artery entrances in the C7 transverse process. The prevalence of anomalies was compared based on patient sex and age.

RESULTS

Evaluating the examinations from 2067 patients (1046 men; 1021 women), 1% of patients exhibited an anomalous presence of anterior tubercles, and 0.3% of patients displayed cervical ribs at the C7 transverse process. The prevalence of anomalies process was significantly higher in men aged less than 40 years than in older men (P < 0.001), whereas the prevalence was not higher in women aged less than 40 years than in older women. The prevalence of vertebral artery entry into the C7 transverse foramen was 0.6%.

CONCLUSION

Although an anomalous vertebral artery entry into the C7 transverse foramen was rare, the prevalence of an anomaly at the C7 transverse process was higher in men aged less than 40 years. Therefore, we recommend performing CT in younger men before cervical nerve ultrasonographic intervention to avoid misinterpretations at the cervical level.

Surgical Anatomy of the Uncinate Process and Transverse Foramen Determined by Computed Tomography

Study Design Computed tomography-based cohort study. Objective Although there are publications concerning the relationship between the vertebral artery and uncinate process, there is no practical guide detailing the dimensions of this region to use during decompression of the intervertebral foramen. The purpose of this study is to determine the anatomic parameters that can be used as a guide for thorough decompression of the intervertebral foramen. Methods Fifty-one patients with three-dimensional computed tomography scans of the cervical spine from 2003 to 2012 were included. On axial views, we measured the distance from the midline to the medial and lateral cortices of the pedicle bilaterally from C3 to C7. On coronal reconstructed views, we measured the minimum height of the uncinate process from the cranial cortex of the pedicle adjacent to the posterior cortex of vertebral body and the maximal height of the uncinate process from the cranial cortex of the pedicle at the midportion of the vertebral body bilaterally from C3 to C7. Results The mean distances from midline to the medial and lateral cortices of the pedicle were 10.1 ± 1.3 mm and 13.9 ± 1.5 mm, respectively. The mean minimum height of the uncinate process from the cranial cortex of the pedicle was 4.6 ± 1.6 mm and the mean maximal height was 6.1 ± 1.7 mm. Conclusions Our results suggest that in most cases, one can thoroughly decompress the intervertebral foramen by removing the uncinate out to 13 mm laterally from the midline and 4 mm above the pedicle without violating the transverse foramen.

Age-related morphologic changes of the vertebral artery in the transverse process. Analysis by multidetector computed tomography angiography

BACKGROUND CONTEXT

The V2 segment of the vertebral artery (VA) ascends and passes through the transverse foramen (TF) of the C6-C1 vertebrae. Atherosclerosis of the VA and degenerative changes in the cervical spine are likely to occur with aging, and subsequent morphologic changes may alter the normal anatomy.

PURPOSE

The aim was to determine the morphologic changes of TF and VA in relation to aging.

STUDY DESIGN/SETTING

This was a retrospective cross-sectional study.

PATIENT SAMPLE

One hundred ten consecutive patients who had undergone computed tomography angiography were included.

METHODS

The subjects were then divided into three groups according to age: Group A, less than 45 years; Group B, from 45 to 65 years; and Group C, older than 65 years. Cases with stenosis and dissection of the VA were excluded from the quantitative analysis. The areas of the VA and TF were measured, and the VA/TF occupation ratio (OR) was calculated accordingly. The presence of VAs tortuosity within the TF was also noted.

RESULTS

The TF was larger in the oldest group, but the difference was not statistically significant. There was also no significant statistical difference among the age groups in terms of the VA and VA/TF ORs (p>.05). In the Group C, the rate of overall tortuosity of the VA was 73%, and arterial tortuosity in the TF was 28.6%. In cases with tortuous VA, C6 and C4 TFs were found to be significantly larger.

CONCLUSIONS

Tortuous VAs tend to be associated with enlargement of C6 and C4 TFs. Knowledge of such changes in the anatomy is crucial during instrumentation used for cervical spine surgeries, to prevent serious complications in patients aged older than 65 years.

Variations in Entrance of Vertebral Artery in Korean Cervical Spine: MDCT-based Analysis

Background

Knowledge of the anatomical variation of the vertebral artery has clinical importance not only for the performance of interventional or surgical procedures itself but also to ensure their safety. We conducted a study of the anatomical variation by reviewing multi-detector computed tomography (MDCT) images of the cervical spine from 460 Korean patients.

Methods

16-row MDCT data from 460 patients were used in this study. We observed 920 vertebral arteries. Examination points included level of entrance of the artery into the transverse foramen of the cervical vertebra, origin site of the vertebral artery, course of a vertebral artery with aberrant entrance.

Result

The vertebral artery in 2 (0.2%) cases in this study entered into the transverse foramen of the 7th cervical vertebra from the left. In 45 (4.9%) cases, the vertebral artery entered into the transverse foramen of the 5th cervical vertebra. Of these, the entrance was on the right in 15 (1.6%) and on the left in 30 (3.3%). We found 17 (1.8%) cases in which the artery entered into the transverse foramen of the 4th cervical vertebra, 10 (1.1%) on the right and 7 (0.7%) on the left side. As is commonly acknowledged, the 6th cervical vertebra was the most common site of entry; the vertebral artery entered the transverse foramen of the 6th cervical vertebra in the remaining 855 (93.0%) cases, on the right in 434 (47.2%) and on the left in 421 (45.8%).

Conclusions

In conclusion, the possibility of an atypical course of the vertebral artery in segments V1 and V2 should be evaluated with magnetic resonance imaging (MRI) or CT images before carrying out procedures involving the anterior cervical vertebrae.

Sizes of the transverse foramina correlate with blood flow and dominance of vertebral arteries

BACKGROUND CONTEXT

Knowing the side of the dominant vertebral artery (VA) may be of utmost importance if the VAs are at risk during spine surgery. Determination of the size of VAs is obtained by using Doppler ultrasonography or angiography. Because VA is the main anatomic structure occupying the transverse foramina (TF), it may be assumed that size of TF and blood flow of VAs should be proportional.

PURPOSE

To investigate if there is a correlation between the sizes of TF and the flow of VAs and determine the diagnostic accuracy of measuring TF to predict dominant side of VA. The specific hypothesis was that the larger side of TF corresponds to the side of the dominant VA.

STUDY DESIGN

This is a morphologically based, prospectively designed, single-center study. Thirty patients (14 male, 16 female) who were treated for degenerative spinal pathologies were included. Patients with cervical fractures, occluded VA, prominent degenerative changes affecting TF, deformity, or previous cervical instrumentation were excluded from the study.

OUTCOME MEASURES

In all patients, computed tomography of the cervical spine and Doppler ultrasonography of VAs were obtained for morphometric analysis.

METHODS

Axial computed tomography cuts at the C6 vertebral level were taken. Two measurements were performed for each foramen: its right to left width and its anteroposterior depth. Blood flow volumes of bilateral VAs were measured using color Doppler.

RESULTS

Diameters of TF ranged between 2.2 and 7 mm, and its width was generally slightly larger than the depth. Transverse foramina were always asymmetric, with no right or left side preference. There was a strong correlation between TF diameters and blood flow of VAs. Between TF width and VA blood flow, the Pearson correlation coefficient was 0.59 (p=.001) for right side and 0.72 for left side (p<.0001). The side of the larger TF matched with the side of dominant VA in 28 of 30 cases (93.3%) (p<.0001). The agreement between the dominant VA and the larger side of TF was almost perfect (Kappa=0.087, p<.0001).

CONCLUSIONS

There was strong correlation between TF diameters and VA blood volume. Our results suggest that TF diameter of C6 level can be used to predict the side of the dominant VA reliably.