Vertebrobasilar dissection: a possible role of whiplash injury in its pathogenesis

Intimal Hemorrhage of Basilar Artery Induced by Severe Vasospasm Following Subarachnoid Hemorrhage: The Experimental Analysis

BACKGROUND

 Cerebral vasospasm, a serious complication of subarachnoid hemorrhage (SAH), has been extensively studied for its neurochemical and pathophysiologic mechanisms. However, the contribution of inner elastic membrane dissection and subintimal hemorrhage to basilar artery occlusion remains underexplored. This study investigates inner elastic membrane-related changes in the basilar artery after SAH.

METHODS

 Twenty-four hybrid rabbits were divided into control, sham, and SAH groups, with SAH induced by autologous blood injection. After 2 weeks, basilar artery changes, vasospasm indexes (VSIs), and dissections were evaluated.

RESULTS

 The SAH group showed significantly higher VSI, with vascular wall thickening, luminal narrowing, convoluted smooth muscle cells, intimal elastic membrane disruption, endothelial cell desquamation, and apoptosis. Some SAH animals exhibited subintimal hemorrhage, inner elastic membrane dissection, and ruptures. Basilar arteries with subintimal hemorrhage had notably higher VSI.

CONCLUSIONS

 These findings highlight the role of subintimal hemorrhage and inner elastic membrane dissection in basilar artery occlusion post-SAH, offering valuable insights into vasospasm pathophysiology.

Imaging in Whiplash-Associated Disorders

"Whiplash," a term describing the severe acceleration and deceleration forces applied to the head, craniocervical junction (CCJ), and cervical spine during trauma, is one of the most frequent mechanisms of injury to the CCJ. The CCJ is a complex region at the transition of the cranium and the cervical spine, essential for maintaining craniocervical stability. In whiplash injuries, the CCJ may be compromised due to underlying ligamentous or, less frequently, osseous, intravertebral disk and/or muscular lesions. Imaging is crucial in detecting acute lesions but may also play a role in the follow-up of chronic pathology because soft tissue lesions and progressive disk pathology could contribute to a whiplash-associated disorder.

Anterior cervical discectomy and fusion is more effective than cervical arthroplasty in relieving atypical symptoms in patients with cervical spondylosis

BACKGROUND AND PURPOSE

Patients with cervical spondylosis often present with concurrent 'atypical symptoms' of unknown etiology that have been associated with cervical spondylotic disease, including dizziness, headache, nausea, tinnitus, blurred vision, palpitations, and memory and gastrointestinal disturbances. Few studies have addressed whether surgical intervention to treat classic symptoms of cervical spondylosis can also effectively alleviate atypical symptoms. Accordingly, the purpose of this study is to compare the ability of cervical arthroplasty (CA) and anterior cervical discectomy and fusion (ACDF) to alleviate atypical symptoms associated with cervical spondylosis.

MATERIALS AND METHODS

A retrospective analysis of 140 patients with cervical spondylosis and associated atypical symptoms was performed. Atypical symptoms were defined vertigo, headache, nausea and vomiting, tinnitus, blur vision, palpitation, hypomnesia, and gastroenteric disturbances not otherwise explained by medical comorbidities. Seventy-eight patients (55.7%) underwent ACDF and 62 (44.3%) patients underwent CA. Demographics, surgical characteristics, patient reported outcome measures (PROMs), radiographs, complication rates, and resolution in atypical symptoms were recorded and compared between groups. Atypical symptoms were assessed using a 20-point system. All the patients had a minimum of five years follow-up.

RESULTS

VAS, SF-36, JOA, and NDI scores improved significantly in all the patients (p < 0.001). At the last follow-up, the fusion rate was 97% in the ACDF group. Atypical symptoms improved in both groups (p < 0.001), although the ACDF group demonstrated greater improvement in headache and vertigo resolution compared to the CA group (p < 0.0001).

CONCLUSIONS

While both ACDF and CA are effective in alleviating atypical symptoms associated with cervical spondylosis, ACDF demonstrated greater improvements in atypical symptoms.

Posterior Inferior Cerebellar Artery/Vertebral Artery Subarachnoid Hemorrhage: A Comparison of Saccular vs Dissecting Aneurysms

BACKGROUND

Two distinct categories of aneurysms are described in relation to the posterior inferior cerebellar artery (PICA) and vertebral artery (VA): saccular (SA) and dissecting (DA) types. This distinction is often unrecognized because abnormalities here are uncommon and most studies are small.

OBJECTIVE

To determine if there are any differences in the clinical presentation, in-hospital course, or outcomes in patients with DA vs SA of the PICA or VA.

METHODS

Thirty-eight patients with a VA or PICA aneurysm were identified from a departmental subarachnoid hemorrhage database and categorized into DA or SA types. Prospectively collected demographic and outcome data (length of stay, discharge Glasgow Outcome Score) were supplemented by abstracting records for procedural data (extraventricular drain [EVD], ventriculoperitoneal [VP] shunt, tracheostomy, and nasogastric feeding). Univariate, binary logistic regression, and Cox regression analysis was used to compare patients with SA vs DA.

RESULTS

Three aneurysms related to arteriovenous malformation were excluded. Five patients were conservatively managed. Of the 30 treated cases, more patients with a DA presented in poor grade (6/13 vs 2/17 SA; P = .035). More DA patients required an EVD (85% vs 29%; P = .003), VP shunt (54% vs 6%; P = .003), tracheostomy (46% vs 6%; P &lt; .01), and nasogastric feeding (85% vs 35%; P = .007). The median length of stay (41 vs 17 d, P &lt; .001) was longer, and the age and injury severity adjusted odds of discharge home were significantly lower in the DA group (P = .008). Thirty-day mortality was not significantly different (23% of DA vs 24% of SA; P = .2).

CONCLUSION

The presentation, clinical course, and outcomes differ in patients with DA vs SA of the PICA and VA.

An update on the management of post-traumatic headache

Recent studies from the UK give the debate about how to deal best with patients suffering from whiplash injury new impetus. Following whiplash injury, about 90% of patients complain about head and/or neck pain, as well as dizziness, sleep problems and anxiety. These symptoms are often referred to as whiplash-associated disorders. In the majority of cases, these complaints develop within a few days or weeks following the accident. However, 30-50% of patients experience prolonged symptoms for more than 6 months, with headache as the main complaint. In accordance with the bio-psycho-social model of chronic post-traumatic headache, the following treatment options have been suggested: (1) proper patient education with detailed explanation of the condition; (2) support of normal movement; (3) avoiding immobilization; (4) resumption of work; and (5) targeted physiotherapy. Based on current study data, intensified physiotherapy seems not to be superior to standard therapy with simple patient education and can therefore not be recommended considering cost-benefit aspects.

Fatal subarachnoid hemorrhage associated with internal carotid artery dissection resulting from whiplash trauma

Spinal injury following inertial loading of the head and neck (whiplash) is a common sequel of low speed traffic crashes. A variety of non-musculoskeletal injuries have been described in association with injury to the spine following whiplash trauma, including traumatic brain injury, vestibular derangement, and cranial nerve injury, among others. Vascular injuries in the head and neck have, however, only rarely been described. We present the case of a middle-aged male who sustained an ultimately fatal injury that resulted from injury to the internal carotid artery (ICA) and intracerebral vascular structures following a hard braking maneuver, with no direct head- or neck contact with the vehicular interior. Based on this unusual mechanism of injury we reviewed hospital data from the United States nationwide inpatient database (NIS) to assess the frequency of similar injuries reportedly resulting from traffic crashes. The post-mortem examination revealed a left internal carotid artery dissection associated with subarachnoid hemorrhage (SAH). Based on the close temporal association, the absent prior history, and the plausibility of the injury mechanism, the injury was attributed to the braking maneuver. An analysis of NIS data demonstrated that the prevalence of subarachnoid hemorrhage is significantly higher when there is a traumatic etiology, and higher yet when the trauma is a traffic crash (odds ratio 3.3 and 4.3, respectively). The presented case, together with the hospital inpatient data analysis, indicate that although SAH in combination with ICA dissection is relatively rare, it is substantially more probable following a traffic crash. In a clinical or forensic setting the inference that magnitude of a trauma was low should not serve as a basis for either excluding a cervical artery dissection from a differential diagnosis, or for excluding the trauma as a cause of a diagnosed dissection. This case report illustrates a rare fatal outcome of inertial load to the head and neck induced by a sudden braking event in a commonly experienced non-collision traffic incident. The likely mechanism of injury resulted from interaction between the occupant and the 3-point seat belt. These findings indicate that ICA dissections are substantially more likely to be associated with SAH following head and neck trauma, regardless of the magnitude of the traumatic event or whether an impact was involved.

Endovascular versus Non-Interventional Therapy for Cervicocranial Artery Dissection in East Asian and Non-East Asian Patients: a Systematic Review and Meta-analysis

Endovascular methods have been increasingly applied in treating cervicocranial artery dissection (CCAD). Anti-thrombotic therapy, which is used in non-interventional care of CCAD patients, has differential effects in East Asian patients. Therefore, we aimed to compare the clinical outcomes of endovascular versus non-interventional therapy for CCAD in East Asians and non-East Asians. A search was performed for studies comparing endovascular and non-interventional approaches to CCAD patients. Rates of recovery, disability, and mortality were used to assess these approaches in East Asian and non-East Asian patients. Subgroup analyses were conducted for CCAD patients with ruptured dissections. Eleven East Asian studies and five non-East Asian studies were included. The subgroup analyses for CCAD patients with ruptured dissections on mortality (East Asian odds ratio [OR] [95% confidence interval [CI]]: 0.24 [0.08-0.71], P = 0.01; I² = 34%) and good recovery (East Asian OR [95% CI]: 3.79 [1.14-12.60], P = 0.03; I² = 54%) revealed that endovascular therapy is significantly superior to non-interventional therapy for East Asians. No differences in treatment effect upon mortality, disability, or good recovery outcomes were found for the CCAD populations-at-large nor for non-East Asian CCAD patients with ruptured dissections. Endovascular therapy appears to be superior to non-interventional therapy for East Asian CCAD patients with ruptured dissections.

Outcome of cervicocranial artery dissection with different treatments: a systematic review and meta-analysis

OBJECTIVE

The purpose of this meta-analysis is to compare clinical outcomes between endovascular treatment and conservative treatment for cervicocranial artery dissection.

METHODS

Medline, Embase, and Cochrane Library databases were searched for studies comparing endovascular treatment versus conservative treatment for cervicocranial artery dissection patients. The period searched was from November 1994 to March 2013. Fifteen observational studies involving 442 cervicocranial artery dissection patients were found. Evaluated outcomes included rate of mortality, disability, and good recovery. The rebleeding rate in subarachnoid hemorrhage (SAH) patients was also recorded and compared.

RESULTS

In general, patients who received endovascular treatment enjoyed a lower mortality rate than those who received conservative treatment (P = .02, odds ratio [OR]: .5, 95% confidence interval [CI]: .27-.90), especially patients having ruptured cervicocranial artery dissection (P = .002, OR: .32, 95% CI .15-.66) and dissecting aneurysms (P = .006, OR: .31, 95% CI .14-.71). Among SAH patients with a Hunt-Hess score of 3 or more, endovascular treatment decreased mortality significantly (P = .006, OR: .22, 95% CI .08-.65), whereas no significant differences between these 2 treatments occurred in patients having a Hunt-Hess score less than 3.

CONCLUSIONS

Endovascular treatment yields a better outcome, with greater benefit in patients with ruptured cervicocranial artery dissection, dissecting aneurysms, and a Hunt-Hess score of 3 or more. Randomized controlled trials comparing these 2 therapeutic strategies are needed.

Clinical characteristics of symptomatic vertebral artery dissection: a systematic review

BACKGROUND

Vertebral artery dissection (VAD) is an important cause of stroke in the young. It can present nonspecifically and may be misdiagnosed with adverse consequences. We assessed the frequency of head/neck pain, other neurological symptoms, and cerebrovascular events in symptomatic VAD.

METHODS

We conducted a systematic review of observational studies, searching electronic databases (MEDLINE, EMBASE) for English-language manuscripts with >5 subjects with clinical or radiologic features of VAD. Two independent reviewers selected studies for inclusion; a third adjudicated differences. Studies were assessed for methodological quality, and clinical data were abstracted. Pooled proportions were calculated.

RESULTS

Of 3996 citations, we screened 511 manuscripts and selected 75 studies describing 1972 VAD patients. The most common symptoms were dizziness/vertigo (58%), headache (51%), and neck pain (46%). Stroke was common (63%), especially with extracranial dissections (66% vs. 32%, P<0.0001), whereas transient ischemic attack (14%) and subarachnoid hemorrhage (10%) were uncommon. Subarachnoid hemorrhage was seen only with intracranial dissections (57% vs. 0%, P=0.003). Fewer than half of the patients had obvious trauma, and only 7.9% had a known connective tissue disease. Outcome was good (modified Rankin scale 0 to 1) in 67% and poor (modified Rankin scale 5 to 6) in 10% of patients.

CONCLUSIONS

VAD is associated with nonspecific symptoms such as dizziness, vertigo, headache, or neck pain. Ischemic stroke is the most common reported cerebrovascular complication. VAD should be considered in the diagnostic assessment of patients presenting with dizziness or craniocervical pain, even in the absence of other risk factors. Future studies should compare clinical findings as predictors in well-defined, undifferentiated populations of clinical VAD suspects.

Lesson of the month (1). Homonymous left hemianopia secondary to traumatic extracranial vertebral artery dissection

This lesson reports the case of a 32-year-old female presenting with left-sided homonymous hemianopia after a road traffic accident. A diagnosis of vertebral artery dissection (VAD) was missed at presentation after an initial computed tomography head scan was normal. Later, VAD was confirmed on neck magnetic resonance imaging. VAD is an uncommon cause of stroke in the young and, to date, there are no current emergency guidelines available for the management of patients with the condition.

The role of tissue damage in whiplash-associated disorders: discussion paper 1

STUDY DESIGN

Nonsystematic review of cervical spine lesions in whiplash-associated disorders (WAD).

OBJECTIVE

To describe whiplash injury models in terms of basic and clinical science, to summarize what can and cannot be explained by injury models, and to highlight future research areas to better understand the role of tissue damage in WAD.

SUMMARY OF BACKGROUND DATA

The frequent lack of detectable tissue damage has raised questions about whether tissue damage is necessary for WAD and what role it plays in the clinical context of WAD.

METHODS

Nonsystematic review.

RESULTS

Lesions of various tissues have been documented by numerous investigations conducted in animals, cadavers, healthy volunteers, and patients. Most lesions are undetected by imaging techniques. For zygapophysial (facet) joints, lesions have been predicted by bioengineering studies and validated through animal studies; for zygapophysial joint pain, a valid diagnostic test and a proven treatment are available. Lesions of dorsal root ganglia, discs, ligaments, muscles, and vertebral artery have been documented in biomechanical and autopsy studies, but no valid diagnostic test is available to assess their clinical relevance. The proportion of WAD patients in whom a persistent lesion is the major determinant of ongoing symptoms is unknown. Psychosocial factors, stress reactions, and generalized hyperalgesia have also been shown to predict WAD outcomes.

CONCLUSION

There is evidence supporting a lesion-based model in WAD. Lack of macroscopically identifiable tissue damage does not rule out the presence of painful lesions. The best available evidence concerns zygapophysial joint pain. The clinical relevance of other lesions needs to be addressed by future research.

Degenerative pathological irritations to cervical PLL may play a role in presenting sympathetic symptoms

The mechanism of cervical vertigo remains unknown. Stimulation of arterial vertebralis caused by osteophyte of the Luschka joint or segmental instability of the cervical spine was considered to be a potential factor contributing to it. Years of studies found that the ischemia of the vertebral artery is not directly correlated with the clinical symptoms of vertigo, and can not be used to explain cervical vertigo as a sole reason. As proven by clinical practical experience, the routine anterior cervical decompression and fusion (ACDF) procedure, in which the degenerative disc and posterior longitudinal ligament (PLL) were often removed, shows positive results for elimination of the sympathetic symptoms. In this article, we hypothesize that: (1) there are sympathetic nerve postganglionic fibers distributed in the PLL or discs; (2) pathological changes secondary to degeneration of the intervertebral disc may cause irritation of sympathetic nerve fibers in PLL or discs, leading to sympathetic symptoms via certain pathways; (3) removal of the PLL or stabilization of the segment which decreases the irritation to PLL will help to eliminate the sympathetic symptoms.

Screening for head, neck, and shoulder pathology in patients with upper extremity signs and symptoms

NARRATIVE REVIEW: Conditions of the head, neck, thorax, and shoulder may occur simultaneously with arm pathology or produce symptoms perceived by the patient to originate in the elbow, wrist, or hand. Identification of the tissue disorder and associated impairments, followed by matching the rehabilitative intervention to address these issues, leads to optimal outcomes. With this goal in mind, the hand therapist needs to recognize clinical findings that signal potentially serious medical conditions of the brain, cervical region, chest, or shoulder. Additionally, less serious but potentially debilitating, musculoskeletal or neurogenic pain from proximal sources must also be differentiated from somatic pain originating in the elbow, wrist, or hand so that the clinician can decide to further examine and intervene or refer to an appropriate health care provider. This article describes clinical findings that suggest the presence of serious medical pathology in the head, neck, or thorax and presents a screening algorithm to assist in discriminating pain derived from local structures in the distal arm from referred pain originating in the more proximal regions of the shoulder, thorax, neck, or brain.

LEVEL OF EVIDENCE

5.

The anatomy and biomechanics of acute and chronic whiplash injury

Whiplash injury is the most common motor vehicle injury, yet it is also one of the most poorly understood. Here we examine the evidence supporting an organic basis for acute and chronic whiplash injuries and review the anatomical sites within the neck that are potentially injured during these collisions. For each proposed anatomical site--facet joints, spinal ligaments, intervertebral discs, vertebral arteries, dorsal root ganglia, and neck muscles--we present the clinical evidence supporting that injury site, its relevant anatomy, the mechanism of and tolerance to injury, and the future research needed to determine whether that site is responsible for some whiplash injuries. This article serves as a snapshot of the current state of whiplash biomechanics research and provides a roadmap for future research to better understand and ultimately prevent whiplash injuries.

Dynamic vertebral artery elongation during frontal and side impacts

BACKGROUND CONTEXT

Elongation-induced vertebral artery (VA) injury has been hypothesized to occur during nonphysiological coupled head motions during automobile impacts. Although previous work has investigated VA elongation during head-turned and head-forward rear impacts, no studies have performed similar investigations for frontal or side impacts.

PURPOSE

The present study quantified dynamic VA elongations during simulated frontal and side automotive collisions, and compared these data with corresponding physiological limits.

STUDY DESIGN/SETTING

In vitro biomechanical study of dynamic VA elongation during simulated impacts.

METHODS

A biofidelic whole cervical spine model with muscle force replication and surrogate head underwent simulated frontal impacts (n=6) of 4, 6, 8, and 10 g or left side impacts (n=6) of 3.5, 5, 6.5, and 8 g.

RESULTS

Average (SD) maximum physiological VA elongation was 7.1 (3.2) mm, measured during intact flexibility testing. Average peak dynamic elongation of right VA during left side impact, up to 17.4 (2.6) mm, was significantly greater (p<.05) than physiological beginning at 6.5 g, whereas the highest average peak VA elongation during frontal impact was 2.5 (2.4) mm, which did not exceed the physiological limit. Side impact, as compared with frontal impact, caused earlier occurrence of average peak VA elongation, 113.8 (13.5) ms versus 155.0 (46.2) ms, and higher average peak VA elongation rate, 608.8 (99.0) mm/s versus 130.0 (62.9) mm/s.

CONCLUSIONS

Elongation-induced VA injury is more likely to occur during side impact as compared with frontal impact.

Prone positioning precautions in plastic surgery

Prone positioning carries with it risks associated with neural and vascular compression. Meticulous attention to avoiding compression will protect against the risks associated with improper positioning, particularly for plastic surgeons.

Vertebral artery injury after blunt cervical trauma: an update

BACKGROUND

Vertebral artery injury (VAI) after blunt cervical trauma has been considered to be rare. The incidence of VAI has increased dramatically within the last decade after a heightened awareness of this entity on the part of spine surgeons. Diagnostic or therapeutic guidelines for VAI have not been established fully, however.

METHODS

A review of the literature published between 1990 and 2004 was conducted.

RESULTS

The incidence of VAI among total blunt trauma admissions ranged from 0.20% to 0.77%. Most VAI patients remained asymptomatic, but sudden unexpected deterioration was often reported. Distraction/extension, distraction/flexion, and lateral flexion injuries were the major mechanisms of injury. Dissection and occlusion were the frequent vascular injury patterns. Facet joint dislocations and the fractures extending into the transverse foramen were the spine injury patterns closely associated with VAI. Digital subtraction angiography was the most sensitive imaging study, but because of invasiveness, its role as a screening study remained questionable. Neuroradiological intervention was used successfully to treat hemorrhagic VAI and progressing vertebrobasilar stroke. Systemic anticoagulation with heparin was the preferred treatment for mild ischemia. Treatment of asymptomatic patients has been controversial because the natural history of VAI has not been elucidated. Prophylactic anticoagulation with heparin or the use of antiplatelet agents was advocated in recent studies.

CONCLUSIONS

Preemptive treatment may be reasonable in selected patients considering the devastating potentials of VAI. The potential risks of heparin or antiplatelet agents in relation to early cervical spine surgery have not been addressed fully, however, and spine surgeons have to weigh the risk and benefit of such treatment cautiously.

Effect of rotated head posture on dynamic vertebral artery elongation during simulated rear impact

BACKGROUND

Elongation-induced vertebral artery injury has been hypothesized to occur during non-physiological coupled axial rotation and extension of head. No studies have quantified dynamic vertebral artery elongation during head-turned rear impacts. Therefore, we evaluated effect of rotated head posture vs. forward head posture at the time of impact on dynamic vertebral artery elongation during simulated rear impacts.

METHODS

A whole cervical spine model with surrogate head and muscle force replication underwent either simulated head-turned (n = 6) or head-forward (n = 6) rear impacts of 3.5, 5, 6.5 and 8 g. Continuous dynamic vertebral artery elongation was recorded using custom transducer and compared to physiological values obtained during intact flexibility testing.

FINDINGS

Average (SD) peak dynamic vertebral artery elongation of up to 30.5 (2.6) mm during head-turned rear-impact significantly exceeded (P < 0.05) the physiological beginning at 5 g. Highest peak elongation of 5.8 (2.1) mm during head-forward rear impact did not exceed physiological limit. Head-turned rear impact caused earlier occurrence of average peak vertebral artery elongation, 84.5 (4.2) ms vs. 161.0 (43.8) ms, and higher average peak vertebral artery elongation rate, 1336.7 (74.5) mm/s vs. 211.5 (97.4) mm/s, as compared to head-forward rear impact.

INTERPRETATION

Elongation-induced vertebral artery injury is more likely to occur in those with rotated head posture at the time of rear impact, as compared to head-forward.

Acute basilar artery dissection treated by emergency stenting in a 13-year-old boy

We report a 13-year-old boy who presented with acute basilar artery occlusion due to traumatic arterial dissection. Because a grave prognosis was expected if left untreated, and the chance of neurological recovery was believed to be unlikely but not zero, given that emergency stenting for the dissection was performed within 6 h of ictus. Recanalization of the basilar artery with stent placement did not change the poor prognosis in this patient because there was extension of dissection into the posterior cerebral arteries.

Infarctus latéro-bulbaire sur dissection intracrânienne suivi d’une hémorragie sous-arachnoïdienne

INTRODUCTION

Intracranial vertebral artery dissecting aneurysms are a recognized cause of subarachnoid hemorrhage and the hemorrhagic recurrence risk after a first rupture of the dissecting aneurysm is high and of poor prognosis. However, when the dissection is discovered in a patient with vertebrobasilar territory ischemia, little is known about the risk of hemorrhagic rupture risk and there is no consensus on management.

OBSERVATION

We report the case of a 49-year-old man who developed subarachnoid hemorrhage 48 hours after the occurrence of a latero-bulbar syndrome caused by a spontaneous dissection with occlusion of the right vertebral artery. The subsequent angiography showed a V4 dissecting aneurysm of the right vertebral artery which was treated by stenting and coiling without any complications.

CONCLUSION

This case underlines the hemorrhagic risk of an intradural vertebral artery dissection and its possible progression to aneurysm. Subsequent angiographic imaging must be carefully examined to search for aneurysms which may require early specific treatment because of the high risk of recurrent bleeding.

Screening for vertebrobasilar insufficiency in patients with neck pain: manual therapy decision-making in the presence of uncertainty

Growing evidence supports the effectiveness of manual therapy interventions in patients with neck pain; however, considerable attention has also been afforded to the potential risks such as vertebrobasilar insufficiency (VBI). Despite the existence of guidelines advocating specific screening procedures, research does not support the ability to accurately identify patients at risk. The logical question becomes, "How does one proceed in the absence of certainty?" Given the lack of clear direction for decision making in the peer-reviewed literature, this commentary discusses the uncertainties that exist regarding the ability to identify patients at risk for VBI. The authors hope that this commentary adds additional perspective on manual therapy decision-making strategies in the presence of uncertainty.

Imaging the vertebral artery

Although conventional intraarterial digital subtraction angiography remains the gold standard method for imaging the vertebral artery, noninvasive modalities such as ultrasound, multislice computed tomographic angiography and magnetic resonance angiography are constantly improving and are playing an increasingly important role in diagnosing vertebral artery pathology in clinical practice. This paper reviews the current state of vertebral artery imaging from an evidence-based perspective. Normal anatomy, normal variants and a number of pathological entities such as vertebral atherosclerosis, arterial dissection, arteriovenous fistula, subclavian steal syndrome and vertebrobasilar dolichoectasia are discussed.

Cervical Artery Dissection. A Comparison of Highly Dynamic Mechanisms: Manipulation versus Motor Vehicle Collision

OBJECTIVE

To examine the similarities and dissimilarities between cervical chiropractic manipulative therapy and whiplash, and their respective relation to cervical artery dissection.

DATA SOURCES

A literature synthesis used MEDLINE-PubMed and MANTIS literature searches. A total list of 99 relevant articles was generated. Additional references were collected from citations incorporated within the included articles.

RESULTS

Both neck manipulation and motor vehicle collision events apply loads to the spinal column rapidly. While neck manipulation loads are slower to develop and displacements smaller, they may reach peak amplitudes on maximum effort comparable to those seen in low-velocity collision experiments. In contrast to reports that the vertebral artery experiences elongations exceeding its physiological range by up to 9.0 mm during simulated whiplash, strains incurred during cervical manipulative therapy have been reported to be approximately one ninth of those required for mechanical failure, comparable to forces encountered in the course of diagnostic range of motion examination. Additionally, long-lasting abnormalities of blood flow velocity within the vertebral artery have been reported in patients following common whiplash injuries, whereas no significant changes in vertebral artery peak flow velocity were observed following cervical chiropractic manipulative therapy.

CONCLUSIONS

Perceived causation of reported cases of cervical artery dissection is more frequently attributed to chiropractic manipulative therapy procedures than to motor vehicle collision related injuries, even though the comparative biomechanical evidence makes such causation unlikely. The direct evidence suggests that the healthy vertebral artery is not at risk from properly performed chiropractic manipulative procedures.

[Whiplash injury of the neck from concepts to facts]

OBJECTIVES

To focus on a topic of traumatology and rehabilitation becoming recently a much debated public health problem.

METHOD

A references search from Medline database with whiplash as keyword was carried out. Were selected articles with abstracts in french or english and focusing on accidentology, biomechanics, demonstrated lesions, epidemiology and treatments.

RESULTS

From 1664 references found, 232 were reviewed. The usual mechanism of crash is a rear-end collision inducing in the occupants of the bumped vehicle a sudden lower cervical spine extension with upper flexion followed by a global flexion. In nearly 50% of the cases, the stress occurring in the collision is comparable to that observed in bumper cars. The velocity changes are seldom up to 15 km/h. A headrest at the level of the center of gravity of the head restrict significantly the extension of the neck. Every structure of the cervical spine could be damaged and mainly the facet joints but the lesions were only demonstrated in severes traumatisms. The discrepancies in incidence among the different countries could be related to their medicolegal system. Although subjectives, the early symptoms are rather similar among patients suggesting true anatomical or functional disorders but the chronicity seems to be mainly related to social and psychological factors. The association of: no posterior midline cervical tenderness, no intoxication, normal alertness, no focal neurological deficit and no painful distracting injuries has a good predictive value of the lack of osteo-articular lesion on X-rays. Except the grade IV of the Quebec task Force (0, no symptom; 1, pain and stiffness; 2, neck complaint and physical signs; 3, neck complaint and neurological signs; 4, fracture or dislocation) the use of a collar should be avoided and the cervical spine should be mobilized.

CONCLUSION

In most whiplash injuries, the mildness should be early stated, mobilization encouraged, and procedures of compensation shortened.