Vertebral artery occlusion associated with cervical spine trauma. A prospective analysis

A Systematic Review and Meta-Analysis of Vertebral Artery Injury After Cervical Spine Trauma

STUDY DESIGN

Systematic Review and Meta-Analysis.

OBJECTIVE

Identify the incidence, mechanism of injury, investigations, management, and outcomes of Vertebral Artery Injury (VAI) after cervical spine trauma.

METHODS

A systematic review and meta-analysis were conducted in accordance with the PRISMA guidelines (PROSPERO-ID CRD42021295265). Three databases were searched (PubMed, SCOPUS, Google Scholar, CINAHL PLUS). Incidence of VAI, investigations to diagnose (Computed Tomography Angiography, Digital Subtraction Angiography, Magnetic Resonance Angiography), stroke incidence, and management paradigms (conservative, antiplatelets, anticoagulants, surgical, endovascular treatment) were delineated. Incidence was calculated using pooled proportions random effects meta-analysis.

RESULTS

A total of 44 studies were included (1777 patients). 20-studies (n = 503) included data on trauma type; 75.5% (n = 380) suffered blunt trauma and 24.5% (n = 123) penetrating. The overall incidence of VAI was .95% (95% CI 0.65-1.29). From the 16 studies which reported data on outcomes, 8.87% (95% CI 5.34- 12.99) of patients with VAI had a posterior stroke. Of the 33 studies with investigation data, 91.7% (2929/3629) underwent diagnostic CTA; 7.5% (242/3629) underwent MRA and 3.0% (98/3629) underwent DSA. Management data from 20 papers (n = 475) showed 17.9% (n = 85) undergoing conservative therapy, anticoagulation in 14.1% (n = 67), antiplatelets in 16.4% (n = 78), combined therapy in 25.5% (n = 121) and the rest (n = 124) managed using surgical and endovascular treatments.

CONCLUSION

VAI in cervical spine trauma has an approximate posterior circulation stroke risk of 9%. Optimal management paradigms for the prevention and management of VAI are yet to be standardized and require further research.

Current Concepts in Imaging Diagnosis and Screening of Blunt Cerebrovascular Injuries

Blunt cerebrovascular injury (BCVI) is an often underrecognized injury occurring in the carotid or vertebral arteries, associated with a risk of ischemic stroke and potential for poor neurological outcome or death. Computed tomographic angiography (CTA) is the most common modality for initial screening and diagnosis. Vessel wall intimal injuries, intraluminal thrombus, dissection, intramural hematoma, pseudoaneurysm, vessel transection, and arteriovenous fistula, are potential findings to be considered in approach to imaging. Identification of high-risk trauma patients based on clinical and radiological risk factors can determine patients at risk of BCVI for targeted screening.

Incidence and Outcome Analysis of Vertebral Artery Injury in Posttraumatic Cervical Spine

Objective:

Vertebral artery injury (VAI) after cervical spine trauma often remains undiagnosed. Despite various clinical studies suggesting simultaneous occurrence of VAI with cervical spine trauma, guidelines regarding screening and management of posttraumatic VAI are yet to be formulated. The primary objective of the current study was to formulate a low-cost screening protocol for posttraumatic VAI, thereby reducing the incidence of missed VAI in developing countries.

Materials and Methods:

This was a single-center prospective study performed on 61 patients using plain magnetic resonance imaging (MRI) as a screening tool to assess the frequency of VAI and routine X-ray to detect morphological fracture patterns associated with the VAI in posttraumatic cervical spine cases. If the MRI study showed any evidence of vascular disruption, then further investigation in the form of computed tomography angiography was done to confirm the diagnosis.

Results:

This study showed the incidence of VAI was 14.75% (9/61). Of 61 patients, 16 had supraaxial, and 45 patients sustained subaxial cervical spine fractures. In the cohort of nine cases of VAI, eight patients had subaxial cervical spine injuries, of which seven were due to flexion-distraction injury. C5–C6 flexion-distraction injury was most commonly associated with VAI (4 cases). Of the nine cases, five succumbed to injury (mortality 55.55%), and 19 patients from the non-VAI group succumbed to injury (mortality 36.53%). From surviving four cases with VAI, two had improvement in the American Spinal Injury Association scale by Grade 1.

Conclusion:

VAI in cervical spine trauma is an underrecognized phenomenon. Plain MRI axial imaging sequence can be an instrumental low-cost screening tool in resource-deficient parts of the world. VAI has tendency to occur with high-velocity trauma like bi-facetal dislocation, which has a high mortality and poor neurological recovery.

Vertebral Artery Injury with Coinciding Unstable Cervical Spine Trauma: Mechanisms, Evidence-based Management, and Treatment Options

Unstable traumatic cervical spine fracture is a commonly encountered neurosurgical issue. Concomitant vertebral artery injuries present a challenge in surgical decision-making regarding the timing and order of surgical intervention with respect to endovascular intervention and internal fixation of the unstable fracture. Currently, there are no studies that have specifically examined stroke rate or outcomes for patients who have vertebral artery injuries and unstable cervical spine fractures with respect to temporal treatment course. The purpose of this paper is to review the current evidence for the standards of diagnosis and management of vertebral artery injuries with coinciding unstable cervical spine injuries and propose an evidence-based algorithm for workup and treatment.

Bilateral Vertebral Artery Occlusion After Cervical Spine Fracture Dislocation

BACKGROUND

Vertebral artery injury is known to potentially occur in conjunction with blunt cervical spine trauma. Rarely, these injuries present bilaterally as complete occlusions. Twelve cases of bilateral vertebral artery occlusions after closed cervical spine trauma have been described in the reported data, nearly all of which demonstrated signs and symptoms of vertebrobasilar insufficiency and ischemia.

CASE DESCRIPTION

Our patient presented after a traumatic C5-C6 flexion-distraction injury that had resulted in bilateral locked facets and spinal cord injury and bilateral vertebral artery occlusions at the V1 segment. However, our patient did not show any cranial symptoms despite his neurovascular injury.

CONCLUSIONS

We present our patient's case as a rare illustration of a bilateral vertebral artery occlusion after blunt cervical spine trauma without clinical vertebrobasilar ischemic sequelae.

Awareness of traumatic occult lateral mass fracture of the cervical spine triggered by the presence of unilateral vertebral artery occlusion: a case report

Introduction

We present an unusual case of traumatic occult lateral mass fracture of the cervical spine with unilateral occlusion of the vertebral artery (VA), that was missed by plain X-ray and magnetic resonance imaging (MRI), but identified by computed tomography (CT) after suspecting high-energy trauma as the underlying cause.

Case presentation

A 67-year-old male was injured in a car accident and came to our institute on foot 4 days after injury with complaints of neck pain and numbness in the right hand. Although, no specific bone injury was visible on plain X-ray, the absence of flow voids in the right VA was confirmed on axial T2-weighted MRI. We suspected high-energy trauma of the cervical spine at that point and performed CT for a more detailed assessment. Consequently, a fracture was detected in the right lateral mass of C6 and we speculated that spontaneous reduction of the fracture-dislocation had occurred. One-stage surgery with posterior fixation was subsequently performed for instability. The patient's preoperative symptoms were improved and neither recanalization of the occlusion nor another VA occlusion was observed after surgery.

Discussion

VA injury occurs frequently as a complication of blunt cervical spine trauma. In the present case, however, the lateral mass fracture was not seen on MRI and missed until the unilateral VA injury was detected. When high-energy trauma of the cervical spine is suspected, it is important to evaluate damage to the spinal cord, bone, soft-tissue, and VA by MRI and CT.

Two-stage corrective surgery for severe rigid cervical kyphotic deformity with unilateral vertebral artery occlusion after old blunt trauma: a case report

Introduction

There are considerable risks for vertebral artery (VA) injury in case of corrective surgery for a severe and rigid cervical kyphotic deformity. This case report describes a rare case of surgical management for pre-existing traumatic rigid cervical kyphosis associated with unilateral VA occlusion.

Case presentation

A 73-year-old male fell down and injured his neck. He was referred to our hospital 10 months after injury because his degree of head drop progressed gradually to a chin-on-chest position such that he could not look straight forward. On plain X-ray, the C2-7 angles in the neutral, flexion, and extension positions were 61°, 71°, and 50°, respectively. CT revealed a collapse of the C5 vertebral body and bone fusion between C4 and C5 in the anterior vertebrae, and unilateral VA occlusion was confirmed by angiography. Two-stage surgery was planned to correct the kyphosis. In the first stage, anterior release of the C4/5 bone-spur fusion and dissection of the intervertebral disk were performed. After release, angiography confirmed neither occlusion nor rupture of the VA. In the second stage, anterior and posterior fixation was performed at correcting position while maintaining slight kyphosis in order to avoid excessive distortion of the VA. The postoperative C2-7 kyphosis angle improved to 16° without any VA injury, and the patient could look forward easily.

Discussion

The degree of correction as well as risk management of VAs should be considered carefully during corrective surgery for severe and rigid cervical kyphosis, especially with unilateral VA occlusion.

The diagnostic accuracy of magnetic resonance angiography for blunt vertebral artery injury detection in trauma patients: A systematic review and meta-analysis

The role of magnetic resonance angiography (MRA) in the evaluation of patients with blunt vertebral artery has not been fully established. Our aim is to define the diagnostic accuracy of MRA in comparison to digital subtraction angiography (DSA) for the detection of blunt vertebral artery injury in trauma patients. A computer-assisted literature search of the PubMed, Scopus, Highwire, Web of Science, and LILACS was conducted, in order to identify studies reporting on the sensitivity and specificity of MRA in comparison to DSA for the detection of blunt vertebral artery injury in trauma patients. The Database search retrieved 91 studies. Five studies fulfilled our eligibility criteria. Two authors assessed the risk of bias and applicability concerns using QUADAS-2. Two-by-two contingency tables were constructed on a per-vessel level. Heterogeneity was tested by the statistical significance of Cochran's Q, and was quantified by the Higgins's I² metric. The pooled estimates of sensitivity and specificity for blunt vertebral artery injury detection with MRA in comparison to DSA were calculated based on the bivariate model. The meta-analysis was supplemented by subgroup and sensitivity analysis, as well as analysis for publication bias. There was significant clinical heterogeneity in the targeted population, inclusion criteria, and MRA related parameters. The reporting bias and applicability concerns were moderate and low, respectively. In the overall analysis, the sensitivity ranged from 25% to 85%, while the specificity varied from 65% to 99%, across studies. According to the bivariate model, the pooled sensitivity and specificity of MRA in the evaluation of patients with blunt vertebral artery was as high as 55% (95% CI 32.1%-76.7%), and 91% (95% CI 66.3%-98.2%), respectively. Subgroup analysis in terms of MRA sequence sensitivity of phase, the contrasted MRA (75% [95% CI 43%-92%]) seemed to be superior to the TOF MRA (46% [95%CI 20%-74%]). The addition of contrast enhancement did not seem to improve the diagnostic yield of MRA. The Egger's test did not identify any significant publication bias (p=0.2). An important limitation of the current meta-analysis is the small number of eligible studies, as well as the lack of studies on newer, high-field MR scanners. We concluded that MRA has a moderate diagnostic accuracy in the diagnosis of blunt vertebral artery injuries. Further studies on high-field magnetic resonance scanners are recommended.

Analysis of Cervical Angiograms in Cervical Spine Trauma Patients, Does it Make a Difference?

STUDY DESIGN

Retrospective review.

OBJECTIVE

To evaluate computed tomography angiogram (CTA) use for diagnosing blunt vertebral artery injury (BVAI) at a single institution, to assess the incidence of BVAI in the studied population, and determine if diagnosis affected care. We also wanted to evaluate if testing and treatment resulted in complications.

SUMMARY OF BACKGROUND DATA

BVAI is an example of a previously underdiagnosed injury. Ease of CTA has simplified vertebral artery evaluation. Injury to the vertebral or carotid arteries is diagnosed in approximately 0.1% of blunt trauma patients when there is high clinical suspicion, or when symptoms of central nervous system damage are apparent on initial examination. Routine screening of asymptomatic patients increases the incidence to approximately 1%.

MATERIALS AND METHODS

After IRB approval, the hospital trauma registry identified patients aged 18-89 presenting with cervical spine fracture from 2006 to 2011. A retrospective review of charts was completed. Data collection included demographic data, fracture pattern, and neurological findings. The indications for and the results of CTA was also reviewed. The type of treatment and any complications were recorded.

RESULTS

A total of 637 charts reviewed. A total of 108 subjects underwent CTA/magnetic resonance angiography; 15 diagnosed with VAI injury. Four received treatment. There were no complications from imaging or treatment of BVAI. Eight subjects without CTA evaluation presented with symptoms potentially related to injury on arrival. Three had neurological decline, although none were eligible for treatment. No routine diagnostic/treatment protocol for vertebral arteries was found at our institution.

CONCLUSIONS

Although neurological sequelae after VAI can be devastating, routine screening after cervical spine fracture may not be warranted. Beside cost, our study suggests it is rarely associated with symptoms, and the asymptomatic patient rarely receives treatment due to concomitant injuries. Our study reinforces the need for further research to establish protocols so that patient-appropriate, cost-effective evaluation and treatment can be provided.

Blunt vertebral vascular injury in trauma patients: ATLS® recommendations and review of current evidence

Blunt cerebrovascular injury (BCVI) encompasses two distinct clinical entities: traumatic carotid artery injury (TCAI) and traumatic vertebral artery injury (TVAI). The latter is the focus of our review. These are potentially devastating injuries which pose a diagnostic challenge in the acute trauma setting. There is still debate regarding the optimal screening criteria, diagnostic imaging modality and treatment methods. In 2012 the American College of Surgeons proposed criteria for investigating patients with suspected TVAI and subsequent treatment methods, caveated with the statement that evidence is limited and still evolving. Here we review the historical evidence and recent literature relating to these recommendations.

Management of Sub-axial Cervical Spine Injuries

Sub-axial cervical spine injuries are commonly seen in patients with blunt trauma. They may be associated with spinal cord injury resulting in tetraplegia and severe permanent disability. Immobilization of the neck, maintenance of blood pressure and oxygenation, rapid clinical and radiological assessment of all injuries, and realignment of the spinal column are the key steps in the emergency management of these injuries. The role of intravenous methylprednisolone administration in acute spinal cord injuries remains controversial. The definitive management of these injuries is based upon recognition of the fracture pattern, assessment of the degree of instability, the presence or absence of neurologic deficit, and other patient related factors that may influence the outcome. Nonoperative treatment comprises of some form of external immobilization for 8 to 12 weeks, followed by imaging to assess fracture healing, and to rule out instability. The goals of surgery are realignment of the vertebral column, decompression of the neural elements and instrumented stabilization.

Emergency Endovascular Treatment of a Penetrating Vertebral Artery Injury with Detachable Coils

The surgical approach is difficult and time-consuming in cases of injury to the bony canal segment of the vertebral artery. Diagnosis and treatment should be performed urgently if the patient has active bleeding. We present a patient with a left vertebral artery injury in a stab wound to the neck in whom emergency endovascular treatment was performed with detachable coils because of ongoing gross bleeding.

Role of magnetic resonance imaging in acute spinal trauma: a pictorial review

Magnetic resonance imaging (MRI) has been playing an increasingly important role in the spinal trauma patients due to high sensitivity for detection of acute soft tissue and cord injuries. More and more patients are undergoing MRI for spinal trauma in the emergency settings, thus necessitating the interpreting physicians to be familiar with MRI findings in spinal trauma. In this pictorial review, we will first describe the normal anatomy of various ligamentous structures. Indications of MRI in spinal trauma as well as the role of MRI in diagnosing spinal cord and soft tissue injuries will then be discussed. Illustrated cases are mainly of cervical spine trauma, but thoracolumbar spine injuries are also included where appropriate in our review.

Multiple Cerebral Infarctions due to Unilateral Traumatic Vertebral Artery Dissection after Cervical Fractures

We report a case of multiple symptomatic cerebral infarctions from a traumatic vertebral artery dissection (VAD) after cervical fractures. A 73-year-old man was admitted with stuporous mentality and left hemiparesis after a motor-vehicle accident. A brain computed tomography (CT) scan at admission showed a traumatic subarachnoid hemorrhage on the left parietal lobe. A cervical CT scan showed left lateral mass fractures on C2, C5, and C6, involving the transverse foramen. Cervical spine magnetic resonance imaging (MRI) revealed loss of signal void on the left vertebral artery. Neck CT angiography showed left VAD starting at the C5 level. Brain MRI revealed acute, multiple cerebral infarctions involving the pons, midbrain, thalamus, corpus callosum, and parietal and frontal lobes on diffusion weighted images. The patient was treated conservatively at the intensive care unit in the acute stage to prevent extent of stroke. Aspirin was started for antiplatelet therapy in the chronic stage. The possibility of symptomatic cerebral infarctions due to traumatic VAD following cervical fracture should be considered.

Corrective spinal surgery may be protective against stroke in patients with blunt traumatic vertebral artery occlusion

OBJECT Approximately 10% of patients with blunt traumatic extracranial cerebrovascular injury have a complete occlusion of the vertebral artery (VA). Ischemic stroke due to embolization of thrombus from an occluded VA following cervical spine surgery has been observed. The risk of ischemic stroke with cervical spine surgery in the presence of an occluded VA, however, has never been determined. METHODS A retrospective chart review of 52 patients with a VA occlusion following a blunt trauma was performed. Clinical and radiographic characteristics were collected and analyzed. RESULTS Ten patients (19.2%) suffered an ischemic stroke attributable to a traumatic VA occlusion. Univariate analysis demonstrated that patients with ischemic stroke were significantly older (p = 0.042) and had a lower rate of cervical spine surgery (p < 0.005). Multivariate analysis found cervical spine surgery to be protective against ischemic stroke (OR 0.049 [95% CI 0.014-0.167], p = 0.014); increasing age and bilateral VA injury (bilateral occlusion or unilateral occlusion with contralateral dissection) were risk factors for ischemic stroke (OR 1.05 [95% CI1.02-1.07], p = 0.065 and OR 13.2 [95% CI 2.98-58.9], p = 0.084, respectively). CONCLUSIONS Traumatic VA occlusion is associated with a risk of ischemic stroke and mortality. Corrective cervical spine surgery potentially decreases the risk of ischemic stroke by stabilizing the spine and thereby reducing motion across the occluded segment of the VA and preventing embolization of thrombus. While a high stoke risk may be inherent to the disease, novel therapies should be investigated.

Emergency department evaluation and treatment of cervical spine injuries

Most spinal cord injuries involve the cervical spine, highlighting the importance of recognition and proper management by emergency physicians. Initial cervical spine injury management should follow the ABCDE (airway, breathing, circulation, disability, exposure) procedure detailed by Advanced Trauma Life Support. NEXUS (National Emergency X-Radiography Utilization Study) criteria and Canadian C-spine Rule are clinical decision-making tools providing guidelines of when to obtain imaging. Computed tomography scans are the preferred initial imaging modality. Consider administering intravenous methylprednisolone after discussion with the neurosurgical consultant in patients who present with spinal cord injuries within 8 hours.

Endovascular therapy for cerebrovascular injuries after head and neck trauma

Cerebrovascular injuries after blunt or penetrating head and neck trauma often lead to significant disability from ischemic stroke, hemorrhagic stroke and uncontrolled extracranial hemorrhage. Trauma causes carotid or vertebral dissection, occlusion, pseudoaneurysm, arteriovenous fistula, vessel transection, traumatic epistaxis, venous sinus thrombosis and carotid cavernous fistula. The rapid development of neuroendovascular techniques over the past two decades has led to effective therapies for each of these injuries. Controlled lesion embolization may use coils, liquid embolics (onyx or n-butyl cyanoarcrylate), polyvinyl alcohol particles or detachable balloons; there is stent angioplasty with uncovered, overlapping and covered stents or mechanical thrombolysis using stent-retrievers or aspiration catheters and the use of balloon occlusion tests and supraselective angiography to delineate safety of vessel sacrifice and to diagnose occult lesions respectively. Furthermore, the proliferation of stroke centers has increased local availability of rapid neuroendovascular expertise at many major trauma centers. Neuroendovascular therapies are less invasive than surgery, can often preserve the injured parent vessels and aid in treating conditions where surgery may be limited. In the absence of randomized controlled trials we present a narrative review of current endovascular therapeutic applications for each of these injuries. This expands the therapies at trauma teams' disposal in the continued effort to control bleeding, reduce secondary injury and prevent disability after trauma. Further research is necessary to inform the role of endovascular techniques after trauma. In particular, comparative studies are necessary to quantify the risk and benefits in conditions where surgical options also exist.

Bilateral cerebellar and brain stem infarction resulting from vertebral artery injury following cervical trauma without radiographic damage of the spinal column: a case report

Vertebral artery injury can be a complication of cervical spine injury. Although most cases are asymptomatic, the rare case progresses to severe neurological impairment and fatal outcomes. We experienced a case of bilateral cerebellar and brain stem infarction with fatal outcome resulting from vertebral artery injury associated with cervical spine trauma. A 69-year-old male was admitted to our hospital because of tetraplegia after falling down the stairs and hitting his head on the floor. Marked bony damage of the cervical spine was not apparent on radiographs and CT scans, so the injury was initially considered to be a cervical cord injury without bony damage. However, an intensity change in the intervertebral disc at C5/C6, and a ventral epidural hematoma were observed on MRI. A CT angiogram of the neck showed the right vertebral artery was completely occluded at the C4 level of the spine. Forty-eight hours after injury, the patient lapsed into drowsy consciousness. The cranial CT scan showed a massive low-density area in the bilateral cerebellar hemispheres and brain stem. Anticoagulation was initiated after a diagnosis of the right vertebral artery injury, but the patient developed bilateral cerebellar and brain stem infarction. The patient's brain herniation progressed and the patient died 52 h after injury. We considered that not only anticoagulation but also treatment for thrombosis would have been needed to prevent cranial embolism. We fully realize that early and appropriate treatment are essential to improve the treatment results, and constructing a medical system with a team of orthopedists, radiologists, and neurosurgeons is also very important.

Traumatic, high-cervical, coronal-plane spondyloptosis with unilateral vertebral artery occlusion: treatment using a prophylactic arterial bypass graft, open reduction, and instrumented segmental fusion

The authors present a case of traumatic, complete, high cervical spine injury in a patient with gradual worsening deformity and neck pain while in rigid cervical collar immobilization, ultimately resulting in coronal-plane spondyloptosis. Due to the extent of lateral displacement of the spinal elements, preoperative evaluation included catheter angiography, which revealed complete right vertebral artery (VA) occlusion. A prophylactic arterial bypass graft from the right occipital artery to the extradural right VA was fashioned to augment posterior circulation blood supply prior to reduction and circumferential instrumented fusion. Following surgery, the patient was able to participate in an aggressive rehabilitation program allowing early mobilization, and he ceased to be ventilator-dependent following implantation of a diaphragmatic pacer. The authors review factors leading to progression of this type of injury and suggest technical pearls as well as highlight specific management pitfalls, including operative risks.

A proposed new system of coding and injury classification for arteries in the trunk and extremities

STUDY DESIGN

Retrospective review of arterial injury with prospective intra-observer and inter-observer analyses.

AIM

To introduce a new classification system for arterial injuries in the extremities and trunk.

METHODS

Retrospective review of all patients with arterial injuries treated at a level I trauma centre during a 3.5-year period. Major arteries were located and coded, and the arteries' lesion was categorised in reference to the alphanumeric format of the AO fracture coding system and injury classification. Each major artery was coded in a numeric format and further divided into three segments: proximal, middle and distal. The severity of artery injury was classified into different types and subtypes in an alphanumeric format. Inter-observer and intra-observer reliabilities were tested.

RESULTS

Systemic arteries were coded and arterial injuries were classified in the alphanumeric notation. The intra- and inter-observers' reliabilities were found to be acceptable in the application of the new system.

CONCLUSION

The preliminary data demonstrate that the new coding and injury classification system for arteries in the trunk and extremities are reliable and efficient for data storage and retrieval, and provide a favourable environment for discussion among different physicians or centres.

A case of traumatic intracranial vertebral artery injury presenting with life-threatening symptoms

Traumatic intracranial vertebral artery injury is a relatively rare but potentially fatal disease. We present a case of a 63-year-old man who presented with sudden onset of loss of consciousness after hitting his head. After immediate resuscitation, he showed quadriplegia and absence of spontaneous breathing. Brain and cervical spine magnetic resonance imaging revealed an atlantoaxial subluxation, fractured C2 odontoid process, left vertebral artery occlusion, and bilateral extensive ischemia in the medulla oblongata and high cervical spinal cord. Digital subtraction angiography demonstrated left vertebral artery dissection just below the level of vertebral body C2.

Clinical indications for arterial imaging in cervical trauma

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To evaluate the clinical indications for acquiring arterial imaging in cervical trauma.

SUMMARY OF BACKGROUND DATA

Cervical spine injuries are very common in high-energy trauma and are frequently seen at Level I trauma centers across the country. A clinical standard of care does not exist to indicate when further evaluation of the cervical vasculature is warranted after a documented cervical spine injury.

METHODS

After institutional review board approval, a retrospective study combining the data from 2 Level I trauma centers was undertaken. An evaluation of every arterial imaging procedure (computed tomography and magnetic resonance angiography) of the cervical spine was collected to further delineate indications and outcomes of these imaging modalities.

RESULTS

From 2005 to 2009, there were a total of 159 patients who underwent cervical arterial imaging at the 2 participating institutions for the indication of cervical trauma with concern for arterial injury. Thirty-six (22.64%) were found to have an injury after arterial imaging. There was a statistically significant correlation with displaced cervical injuries (P < 0.0153), which were defined as cervical dissociations or perched and/or jumped facets. The other statistically significant correlation was the presence of a neurological deficit (P < 0.001), defined as any presenting deficit on sensory or motor examination. Level of injury defined as axial (O-C2) versus subaxial (C3-C7), age, body mass index, and history of cigarette smoking were not statistically related to vascular injury.

CONCLUSION

Our retrospective evaluation indicates that there should be a lower threshold for obtaining arterial imaging with cervical injury patterns historically known to compromise the vasculature, which also have concomitant displaced cervical spine injuries and/or a neurological deficit.

Incidence of blunt cerebrovascular injury in low-risk cervical spine fractures

BACKGROUND

It has been suggested that specific cervical spine fractures (CSfx) (location at upper cervical spine [CS], subluxation, or involvement of the transverse foramen) are predictive of blunt cerebrovascular injury (BCVI). We sought to determine the incidence of BCVI with CSfx in the absence of high-risk injury patterns.

METHODS

We performed a retrospective study in patients with CSfx who underwent evaluation for BCVI. The presence of recognized CS risk factors for BCVI and other risk factors (Glasgow coma score ≤ 8, skull-based fracture, complex facial fractures, soft-tissue neck injury) were reviewed. Patients were divided into 2 groups based on the presence/absence of risk factors.

RESULTS

A total of 260 patients had CSfx. When screened for high-risk pattern of injury for BCVI, 168 patients were identified and 13 had a BCVI (8%). The remaining 92 patients had isolated low CSfx (C4-C7) without other risk factors for BCVI. In this group, 2 patients were diagnosed with BCVI (2%). Failure to screen all patients with CSfx would have missed 2 of 15 BCVIs (13%).

CONCLUSIONS

We propose that all CS fracture patterns warrant screening for BCVI.

The security analysis of transpedicular screw fixation in the lower cervical spine and a case report

STUDY DESIGN

This study evaluated the anatomical parameters of the lower cervical spine by imaging methods and reported a case.

OBJECTIVE

To explain low neurovascular injury rate and provide some suggestions in cervical transpedicular screw fixation (CTSF).

SUMMARY OF BACKGROUND DATA

Because of anatomical complexity and possible severe complications, application of CTSF was limited. However, recent studies have indicated that although cervical pedicular screw perforations may happen, severe complications seldom occur.

METHODS

In 20 patients, several anatomical parameters were obtained on computed tomographic angiography (CTA) images of C3-C6, including the inner diameter of vertebral artery (d), the maximal width (A) and height (B) of the transverse foramen, the shortest distance between vertebral artery and cervical pedicle (h), and the angle between the longitudinal axis of pedicle and the hypothetical screw that just touches the vertebral artery (largest safe angle, LSA). Another 35 patients were chosen to measure the shortest distance between cervical pedicle and cervical spinal cord (H) and the angle between the longitudinal axis of pedicle and the hypothetical screw that just touches the cervical spinal cord (smallest angle, SA) on magnetic resonance imaging (MRI) of C4-C7.

RESULTS

Between the left and the right sides, there was no statistically significant difference for d, A, B, h, and LSA at C3-C6 or H and SA at C4-C7. d, h, and H were, respectively, 3.97 ± 0.65 mm, 0.89 ± 0.44 mm, and 6.56 ± 2.10 mm, and there was no statistically significant difference among C3-C6 for d and h or among C4-C7 for H. LSA at C6 was larger than that at C3, C4, and C5; it increased from C5 to C7.

CONCLUSION

There was an "escaping space" for the vertebral artery and spinal cord. CTSF in the superior part of pedicle was relatively safer from accidental perforation of the vertebral artery than CTSF in the inferior part, and in C6 and C7, CTSF was safer from this injury than in C3, C4, and C5.

Fatal outcome after brain stem infarction related to bilateral vertebral artery occlusion - case report of a detrimental complication of cervical spine trauma

BACKGROUND

Vertebral artery injury (VAI) after blunt cervical trauma occurs more frequently than historically believed. The symptoms due to vertebral artery (VA) occlusion usually manifest within the first 24 hours after trauma. Misdiagnosed VAI or delay in diagnosis has been reported to cause acute deterioration of previously conscious and neurologically intact patients.

CASE PRESENTATION

A 67 year-old male was involved in a motor vehicle crash (MVC) sustaining multiple injuries. Initial evaluation by the emergency medical response team revealed that he was alert, oriented, and neurologically intact. He was transferred to the local hospital where cervical spine computed tomography (CT) revealed several abnormalities. Distraction and subluxation was present at C5-C6 and a comminuted fracture of the left lateral mass of C6 with violation of the transverse foramen was noted. Unavailability of a spine specialist prompted the patient's transfer to an area medical center equipped with spine care capabilities. After arrival, the patient became unresponsive and neurological deficits were noted. His continued deterioration prompted yet another transfer to our Level 1 regional trauma center. A repeat cervical spine CT at our institution revealed significantly worsened subluxation at C5-C6. CT angiogram also revealed complete occlusion of bilateral VA. The following day, a repeat CT of the head revealed brain stem infarction due to bilateral VA occlusion. Shortly following, the patient was diagnosed with brain death and care was withdrawn.

CONCLUSION

Brain stem infarction secondary to bilateral VA occlusion following cervical spine trauma resulted in fatal outcome. Prompt imaging evaluation is necessary to assess for VAI in cervical trauma cases with facet joint subluxation/dislocation or transverse foramen fracture so that treatment is not delayed. Additionally, multiple transportation events are risk factors for worsening when unstable cervical injuries are present. Close attention to proper immobilization and neck position depending on the mechanism of injury is mandatory.

Vertebral artery injuries following cervical spine trauma: a prospective observational study

PURPOSE

The purpose of this study was to report on the incidence, diagnosis and clinical manifestation of VAI following cervical spine injuries observed in a prospective observational study with a standardized clinical and radiographical protocol.

METHODS

During a 16-year period, 69 (mean age: 43 ± 20.7 years; 25 female, 44 male) of 599 patients had cervical spine injury suspicious for VAI due to facet luxation and/or fractures extending into the transverse foramen. Diagnosis and management of these patients followed a previously published protocol (Kral in Zentralbl Neurochir 63:153-158, 2002). Digital subtraction angiography (DSA) was performed in all 69 patients. Injury grading of VAI was done according to Biffl et al. (Ann Surg 231:672-681, 2000). All patients with VAI were treated with anticoagulation (heparin followed by ASS) for 6 months.

RESULTS

In cases suspicious for VAI, the incidence of VAI detected by DSA was 27.5% (n = 19 of 69 patients). VAI Grade I occurred in 15.8%, Grade II in 26.3%, Grade IV in 52.6% and Grade V in 5.2%. Of 19 patients, 4 (21%) had clinical signs of vertebrobasilar ischemia. Two patients died in hospital after 4 and 21 days respectively. Of 69 patients, 33 (47.8%) with suspected VAI had unstable spine injuries and were treated surgically.

CONCLUSION

In patients with cervical spine fractures or dislocations crossing the course of the vertebral artery, VAI are relatively frequent and may be associated with significant morbidity and mortality. VAI were identified by DSA in 27.5%. Despite anticoagulation therapy, 5.8% became clinically symptomatic and 2.9% died due to cerebrovascular ischemia.

Vertebral artery injury after cervical spine trauma: A prospective study using computed tomographic angiography

Background:

Although the vertebral artery injuries (VAI) associated with cervical spine trauma are usually clinically occult, they may cause fatal ischemic damage to the brain stem and cerebellum.

Methods:

We performed a prospective study using computed tomographic angiography (CTA) to determine the frequency of VAI associated with cervical spine injuries and investigate the clinical and radiological characteristics. Between January 2005 and August 2007, 99 consecutive patients with cervical spine fractures and/or dislocations were prospectively evaluated for patency of the VA, using the CTA, at the time of injury.

Results:

Complete disruption of blood flow through the VA was demonstrated in seven patients with unilateral occlusion (7.1%). There were four men and three women with a mean age of 43 (range, 33-55 years). Unilateral occlusion of the right vertebral artery occurred in four patients and of the left in three. Regarding the cervical injury type, two cases were cervical burst fractures (C6 and C7), two had C4-5 fracture/dislocations, two had a unilateral transverse foraminal fracture, and one had dens type III fracture. All patients presented with good patency of the contralateral VA. None of the patients developed secondary neurological deterioration due to vertebrobasilar ischemia during the follow-up period with a mean duration of 23 months.

Conclusions:

VAI should be suspected in patients with cervical trauma that have cervical spine fractures and/or dislocations or transverse foramen fractures. CTA was useful as a rapid diagnostic method for ruling out VAI after cervical spine trauma.

Correlation of C2 fractures and vertebral artery injury

STUDY DESIGN

Retrospective review of prospectively collected data.

SUMMARY OF BACKGROUND DATA

Vertebral artery injuries (VAI) occur commonly after cervical spine trauma. No study has yet examined the association between VAI and specific variants of C2 fractures.

OBJECTIVE

To evaluate the incidence of VAI (as defined by magnetic resonance imaging/angiography [MRI/A]) in subtypes of C2 fractures. To define the association between the incidence, morphology, and severity of C2 fractures, based on fracture angulation and comminution, and the occurrence of VAI.

METHODS

Patients admitted to the hospital with C2 fractures between October 2006 and December 2008 to a tertiary care referral center were identified through a prospectively maintained database. Computed tomography (CT) and MRI/A studies were individually reviewed to evaluate the specific C2 fracture type and the occurrence of VAI. Fracture displacement and angulation were measured. Incidence of VAI was compared between different types and subtypes of C2 fractures. The effects of displacement and angulation of the fracture, morphology of foramen transversarium fracture, patient age, and patient gender on VAI were also analyzed.

RESULTS

One hundred one patients were identified with C2 fractures that met inclusion criteria, and 18 (17.8%) had VAI by MRI/A. There was no correlation between fracture types and VAI. However, in subtype analysis, there was a correlation of VAI with traumatic spondylolisthesis of axis (TSA) and greater degree of angulation (P = 0.0023), communition fracture (P = 0.0341), and presence of bone fragment(s) within the foramen transversarium (P = 0.0075). Multivariate logistic regression indicated that age, gender and the presence of fragments within foramen transversarium were associated with greater risk of VAI.

CONCLUSION

Vertebral artery injuries are more likely to occur in C2 fractures with comminuted fractures involving the foramen transversarium, with fractures manifesting bony fragment(s) within the foramen transversarium, or with fractures having greater angulation. These risk factors should be considered when a patient presents with isolated axis fracture.

Blunt cerebrovascular injury practice management guidelines: the Eastern Association for the Surgery of Trauma

BACKGROUND

Blunt injury to the carotid or vertebral vessels (blunt cerebrovascular injury [BCVI]) is diagnosed in approximately 1 of 1,000 (0.1%) patients hospitalized for trauma in the United States with the majority of these injuries diagnosed after the development of symptoms secondary to central nervous system ischemia, with a resultant neurologic morbidity of up to 80% and associated mortality of up to 40%. With screening, the incidence rises to 1% of all blunt trauma patients and as high as 2.7% in patients with an Injury Severity Score of >or=16. The Eastern Association for the Surgery of Trauma organization Practice Management Guidelines committee set out to develop an EBM guideline for the screening, diagnosis, and treatment of BCVI.

METHODS

A computerized search of the National Library of Medicine/National Institute of Health, Medline database was performed using citations from 1965 to 2005 inclusive. Titles and abstracts were reviewed to determine relevance, and isolated case reports, small case series, editorials, letters to the editor, and review articles were eliminated. The bibliographies of the resulting full-text articles were searched for other relevant citations, and these were obtained as needed. These papers were reviewed based on the following questions: 1. What patients are of high enough risk, so that diagnostic evaluation should be pursued for the screening and diagnosis of BCVI? 2. What is the appropriate modality for the screening and diagnosis of BCVI? 3. How should BCVI be treated? 4. If indicated, for how long should antithrombotic therapy be administered? 5. How should one monitor the response to therapy?

RESULTS

One hundred seventy-nine articles were selected for review, and of these, 68 met inclusion criteria and are excerpted in the attached evidentiary table and used to make recommendations.

CONCLUSIONS

The East Practice Management Guidelines Committee suggests guidelines that should be safe and efficacious for the screening, diagnosis, and treatment of BCVI. Risk factors for screening are identified (see ), screening modalities are reviewed indicating that although angiography remains the gold standard, multi-planar (>or==8 slice) CT angiography may be equivalent, and treatment algorithms are evaluated. It is noted that change in the diagnosis and management of this injury constellation is rapid due to technological advancement and the difficulties inherent in performing randomized prospective trials in this patient population.

Blunt vertebral artery injuries in the era of computed tomographic angiographic screening: incidence and outcomes from 8,292 patients

INTRODUCTION

Blunt injuries to the vertebral artery (BVI) are rare. Recent improvements in the multidetector computer tomography (MDCT) technology and increased use of screening protocols have led to a greater number of these injuries identified. Well-defined treatment recommendations are still lacking, and it is unclear whether screening and treatment lead to improved outcome.

METHODS

All patients who met predefined screening criteria were screened for BVI with a MDCT angiogram (MDCT-A). All patients identified with BVI were treated based on injury grade and associated injuries. Hospital course, morbidity, mortality, and follow-up were recorded and analyzed.

RESULTS

A total of 8,292 patients were admitted for blunt injuries during this time period. Forty-four patients were found to have 47 BVI (three bilateral). Pharmacologic treatment with anticoagulants (AC)-heparin and warfarin-or an antiplatelet agent-clopidogrel and aspirin-was initiated in 37 patients (84%). Angiographic coiling was performed in eight patients (18%), and two (5%) had endovascular stents placed. Four patients developed signs of cerebral ischemia (9%), of whom three died and one recovered completely. Overall mortality rate was 16% (7/44). BVI-related mortality occurred in three patients (7%). Of these, two patients had bilateral vertebral artery occlusion or transaction, and death was considered nonpreventable. One death occurred in a patient with a unilateral vertebral dissection developed a posterior circulation infarct. Anticoagulation was felt to be contraindicated in this patient initially due to intracranial hemorrhage. This was deemed the only potentially preventable BVI-related mortality. Annual BVI-related mortality rate in the 4 years before initiating the screening protocol was 0.75 cases per year. During this study period, it was 0.57 cases per year.

CONCLUSION

Under an aggressive screening and individualized treatment protocol for BVI, we had very few potentially preventable BVI-related strokes and deaths. We are unable to conclude; however, based on historical controls that either screening or treatment improved overall outcome.

A multivariate logistic regression analysis of risk factors for blunt cerebrovascular injury

INTRODUCTION

The diagnosis of blunt cerebrovascular injuries (BCVI) has improved with widespread adaptation of screening protocols and more accurate multi-detector computed tomography (MDCT-A) angiography. The population at risk and for whom screening is indicated is still controversial. To help determine which blunt trauma patients would best benefit from screening we performed a comprehensive analysis of risk factors associated with BCVI.

METHODS

All patients with BCVI from June 12, 2000 (the date at which our institution began screening for these injuries) to June 30, 2009 were identified by the primary author (JDB) and recorded in a prospective database. Associated injuries were identified retrospectively by International Classification of Diseases, Ninth Revision (ICD-9) code and compared with similar patients without BCVI. Demographic information was also compared from data obtained from the trauma registry. Univariate analyses exploring associations between individual risk factors and BCVI were performed using Fisher's exact test for dichotomous variables and Student's t test for continuous variables. Additionally, relative risk (RR) was calculated for dichotomous variables to describe the strength of the relationship between the categorical risk factors and BCVI. Multivariate logistic regression models for BCVI, BCAI (blunt internal carotid artery injury), and BVAI (blunt vertebral artery injury) were developed to explore the relative contributions of the various risk factors.

RESULTS

One hundred two patients with BCVI were identified out of 9935 blunt trauma patients admitted during this time period (1.03% incidence). Fifty-nine patients (0.59% incidence) had a BVAI and 43 patients (0.43% incidence) had a BCAI. Univariate analysis found cervical spine fracture (CSI) (RR = 10.4), basilar skull fracture (RR = 3.60), and mandible fracture (RR = 2.51) to be most predictive of the presence of BCVI (P < .005). Independent predictors of BCVI on multivariate logistic regression were CSI (OR = 7.46), mandible fracture (OR = 2.59), basilar skull fracture (OR = 1.76), injury severity score (ISS) (OR = 1.05), and emergency department Glasgow Coma Scale (ED-GCS) (OR = 0.93): all P < .05.

CONCLUSIONS

Blunt trauma patients with a high risk mechanism and a low GCS, high injury severity score, mandible fracture, basilar skull fracture, or cervical spine injury are at high risk for BCVI should be screened with MDCT-A.

Modeling spinal cord contusion, dislocation, and distraction: characterization of vertebral clamps, injury severities, and node of Ranvier deformations

Spinal cord contusion and transection models are widely used for studying spinal cord injury (SCI). Clinically, however, other biomechanical injury mechanisms such as vertebral dislocation and distraction frequently occur, but these injuries are difficult to produce in animals. We mechanically characterize a vertebral clamping strategy that enables the modeling of vertebral dislocation and distraction injuries--in addition to the standard contusion paradigm--in the rat cervical spine. These vertebral clamps have a stiffness of 83.6+/-18.9 N/mm and clamping strength 64.7+/-10.2N which allows injuries to be modeled at high-speed (approximately 100 cm/s). Logistic regression indicated that a moderate-to-severe injury, with an acute mortality rate of 10%, occurs at 2.6 mm of C4/5 dorso-ventral dislocation and 4.1 mm of rostro-caudal distraction between C4 and C5. Injuries produced by dislocation and distraction exhibited features of axonal damage that were absent in contusion injuries. We conducted morphometric analysis at the nodes of Ranvier using immunohistochemistry for potassium channels (Kv1.2) in the juxtaparanodal region. Following distraction injuries, elongated nodes of Ranvier were observed up to 4mm rostral to the lesion. In contrast, contusion injuries produced distortions in nodal geometry which were restricted to the vicinity of the lesion. The greatest deformations in node of Ranvier geometry occurred at the dislocation epicenter. Given the importance of white matter damage in SCI pathology, the distinctiveness of these injury patterns demonstrate that the dislocation and distraction injury models complement existing contusion models. Together, these three animal models span a broader clinical spectrum for more reliably gauging the potential human efficacy of therapeutic strategies.

Management and outcomes of patients undergoing surgery for traumatic cervical fracture-subluxation associated with an asymptomatic vertebral artery injury

STUDY DESIGN

Retrospective clinical series.

OBJECTIVE

To evaluate the management and outcomes of patients with unilateral, asymptomatic vertebral artery occlusion (VAO) undergoing surgery for cervical fractures associated with subluxation.

SUMMARY OF BACKGROUND DATA

The management of VAO is controversial with several treatment options available, including observation alone, antiplatelet therapy, or anticoagulation therapy.

METHODS

A chart review inclusive of the years 2004 to 2006 was performed to include patients who presented after nonpenetrating trauma with cervical fracture associated with subluxation requiring surgery. An associated asymptomatic VAO was also required for inclusion. Eight patients were identified.

RESULTS

Seven patients were male and the mean age was 26.8 years. Six patients suffered an associated spinal cord injury. Three patients underwent closed reduction before surgical stabilization. Five patients underwent open reduction with stabilization. No patient received treatment for VAO before reduction. Postoperative treatment for VAO was variable, with 5 of 8 patients undergoing observation alone. The remaining 3 patients were treated with aspirin therapy, although 1 patient received heparin intravenously for 1 day. None of the patients experienced an ischemic complication.

CONCLUSIONS

Reduction of a fracture, whether closed or open, without treatment of an associated asymptomatic VAO seems safe. Postoperative management of VAO consisting of either observation alone or aspirin therapy also seems to be a safe option.

Clinical study and comparison of magnetic resonance angiography (MRA) and angiography diagnosis of blunt vertebral artery injury

BACKGROUND

Two-dimensional time-of-flight (2D TOF) magnetic resonance angiography (MRA) is the major method for detecting vertebral artery injury (VAI). But there is still controversy over MRA's accuracy in detecting VAI of varying degrees, a technique for which there are no animal studies found in the literature. The purpose of this study was to evaluate the value of MRA for detecting vertebral artery injury in cervical spinal trauma patients and to conduct a comparative study of MRA and angiography of blunt vertebral artery injury in an animal experiment.

METHODS

In clinical study, 319 patients with close cervical spinal trauma underwent 2D TOF MRA prospective examination. The strike-induced flexion injury model of the cervical spine was constructed based on animal experiment with 14 adult dogs. X-ray studies were performed immediately after injury. 2D TOF MRA and angiography were formed within 24 to 36 hours.

RESULTS

Vertebral artery injury was detected by 2D TOF MRA in 52 of the 319 patients. Of the 52 patients, there were 51 unilateral vertebral artery injuries, including 22 injuries on the left vertebral artery and 29 on the right vertebral artery. One patient sustained bilateral vertebral artery injury. Seven dogs had unilateral VAI (5 on the left, 2 on the right), and two dogs had narrower-than-normal left vertebral arteries on MRA examination. Angiography showed occlusion exactly in seven dogs with unilateral vertebral artery injury detected by MRA and no abnormal findings were detected in five dogs without vertebral artery injury on MRA. In two dogs with incomplete left vertebral artery flow-related enhancement on MRA, angiography showed occlusion in one dog and no vertebral injury with normal image in the other.

CONCLUSIONS

2D TOF MRA is an effective detection method of blunt vertebral artery injury but it might not be able to differentiate spasm, a small disruption of intima, from others under certain conditions.

Significance of magnetic resonance imaging in the diagnosis of vertebral artery injury associated with blunt cervical spine trauma

Vertebral artery injury associated with non-penetrating cervical trauma is rare. We report 11 cases of vertebral artery injury diagnosed with magnetic resonance imaging (MRI) after blunt trauma to the cervical spine and discuss about the importance of MRI in the diagnosis of this injury. Seven cases were caused by motor vehicle accidents, three by diving accidents, and one by static compression of the neck. All of the patients had documented cervical spine fractures and dislocations. In three patients, the diagnosis of complete occlusion of the vertebral artery was made on the basis of MRI and digital subtraction angiography (DSA). In the other patients, mural injuries of the vertebral artery were demonstrated with DSA. These 11 patients presented with acute, nonspecific changes in neurological status. Two had infarctions of the cerebellum and brainstem. None were treated with anticoagulants. All of them survived and were discharged to other hospitals for physical and occupational therapy. Although DSA remains the gold standard for diagnosing vertebral artery injuries, MRI is a newer modality for assessing cervical cord injury, and it may be useful for evaluating the presence of vertebral injury after blunt cervical spine trauma.

Blunt cerebrovascular injury: an evaluation from a major trauma centre

BACKGROUND

Blunt cerebrovascular injury (BCVI), although uncommon, is associated with substantial morbidity and mortality and remains poorly understood. This study was conducted to determine the pattern and outcome of BCVI at a major trauma centre.

METHODS

A retrospective review of all trauma admissions between 1996 and 2004 at Liverpool Hospital, the major trauma service for south-west Sydney, was undertaken using the hospital's computerized trauma registry.

RESULTS

Fourteen of the 7788 (0.18%) admitted blunt trauma patients sustained BCVI. Blunt carotid injury occurred in 10 of 14 and blunt vertebral injury occurred in 4 of 14 patients. Road trauma accounted for 9 of 14 cases. The median time to diagnosis was 2 days (range 1-45 days). The stroke rate was 36%, and the overall mortality was 29%.

CONCLUSION

This study identified BCVI as a relatively infrequent occurrence but with significant mortality and morbidity rates. Practice guidelines for both the screening and management of this patient group need to be developed and introduced in this major trauma centre.

Angiographic frequency of blunt cerebrovascular injury in patients with carotid canal or vertebral foramen fractures on multidetector CT

PURPOSE

Blunt carotid injuries (BCI's) and blunt vertebral artery injuries (BVI's), known jointly as BCVI's, are common in "high risk" patients. The purpose is to evaluate the rate of occurrence of BCI/BVI in patients screened purely by the radiologic criteria of fracture through the carotid canal or vertebral transverse foramina, or significant cervical subluxation, noted by multidetector CT.

METHODS

Seventy-one patients with 108 catheterized vessels were included over a 13-month interval. The angiographic examinations were prompted by current hospital protocol, solely by the presence of fractures involving/adjacent to the carotid canal, cervical fractures involving/adjacent to the foramen transversarium, or cervical fractures with significant subluxation. The incidence of each grade of blunt injury was calculated after review of the CT scans and catheter angiograms by two neuroradiologists.

RESULTS

Two thousand and seventy-three total blunt trauma admissions occurred during the time period, with a BCVI rate of 0.92-1.0% (depending on the reviewer), similar to previous studies. Mean time to catheter angiography was 16.6 h. Of the 71 included patients, there were 11-12 BCI's and 10-12 BVI's, an overall rate of 27-30% of BCVI in the patients with foraminal fractures. Interobserver agreement in reviewing the catheter angiograms was excellent (Kappa 0.795). Of note, three internal carotid pseudoaneurysms resolved spontaneously after anticoagulation or aspirin.

CONCLUSION

This study confirms that there is a high rate of BCVI in the presence of carotid canal or vertebral foramen fractures that are noted by multidetector CT. Utilization of purely radiologic criteria of foraminal involvement may be a significant screening tool in the decision of whether to evaluate these patients acutely by catheter or CT angiography, and for early detection of patients at risk for symptomatology, to initiate prompt, prophylactic treatment.

Diagnosis and treatment of a chronic atlanto-occipital subluxation in a dog

A 6-year-old Labrador retriever-cross was evaluated for an abnormal gait and head carriage 6 weeks after suffering trauma. The dog was presented with an ambulatory tetraparesis and was reluctant to move his head. Myelography and computed tomography demonstrated a subluxation of the atlanto-occipital joint with compression of the spinomedullary junction and the brain stem by the occipital bone. Removal of the compressive part of the occipital bone resulted in improvement of the clinical signs within 6 weeks, and resolution of clinical signs occurred 8 months after surgery.