Investigation of whiplash injuries in the upper cervical spine using a detailed neck model

Whiplash injuries continue to have significant societal cost; however, the mechanism and location of whiplash injury is still under investigation. Recently, the upper cervical spine ligaments, particularly the alar ligament, have been identified as a potential whiplash injury location. In this study, a detailed and validated explicit finite element model of a 50th percentile male cervical spine in a seated posture was used to investigate upper cervical spine response and the potential for whiplash injury resulting from vehicle crash scenarios. This model was previously validated at the segment and whole spine levels for both kinematics and soft tissue strains in frontal and rear impact scenarios. The model predicted increasing upper cervical spine ligament strain with increasing impact severity. Considering all upper cervical spine ligaments, the distractions in the apical and alar ligaments were the largest relative to their failure strains, in agreement with the clinical findings. The model predicted the potential for injury to the apical ligament for 15.2 g frontal or 11.7 g rear impacts, and to the alar ligament for a 20.7 g frontal or 14.4 g rear impact based on the ligament distractions. Future studies should consider the effect of initial occupant position on ligament distraction.     

Cervical spine vertebral and facet joint kinematics under whiplash.

Whiplash injuries sustained during a rear-end automobile collision have significant societal impact. The scientific literature on whiplash loading is both diverse and confusing. Definitive studies are lacking to describe the local mechanisms of injury that induce either acute or chronic pain symptoms. A methodology has been presented to quantify the kinematics of the cervical spine components by inducing controlled whiplash-type forces to intact human head-neck complexes. The localized facet joint kinematics and the overall segmental motions of the cervical spine are presented. It is anticipated that the use of this methodology will assist in a better delineation of the localized mechanisms of injury leading to whiplash pain.     

Cervical helical axis characteristics and its center of rotation during active head and upper arm movements-comparisons of whiplash-associated disorders, non-specific neck pain and asymptomatic individuals

The helical axis model can be used to describe translation and rotation of spine segments. The aim of this study was to investigate the cervical helical axis and its center of rotation during fast head movements (side rotation and flexion/extension) and ball catching in patients with non-specific neck pain or pain due to whiplash injury as compared with matched controls. The aim was also to investigate correlations with neck pain intensity. A finite helical axis model with a time-varying window was used. The intersection point of the axis during different movement conditions was calculated. A repeated-measures ANOVA model was used to investigate the cervical helical axis and its rotation center for consecutive levels of 15 degrees during head movement. Irregularities in axis movement were derived using a zero-crossing approach. In addition, head, arm and upper body range of motion and velocity were observed. A general increase of axis irregularity that correlated to pain intensity was observed in the whiplash group. The rotation center was superiorly displaced in the non-specific neck pain group during side rotation, with the same tendency for the whiplash group. During ball catching, an anterior displacement (and a tendency to an inferior displacement) of the center of rotation and slower and more restricted upper body movements implied a changed movement strategy in neck pain patients, possibly as an attempt to stabilize the cervical spine during head movement.     

Impairment of proprioception after whiplash injury

Whiplash injury usually occurs in traffic accidents. Persons experienced this injury might have an impairment of proprioception clinically expressed as inability to determine the exact position of their heads. The aim of this study was to examine the loss of proprioception in people who had a whiplash injury. The study included 60 subjects with cervical spine injury, aged 20 to 50 years and 60 healthy volunteers matched by sex and age. The instrument used for cervical spine mobility assessment was the Cervical Measurement System (CMS), which determines the ability of subjects to return their head in the exact position as it was before they turned it 30 degrees left or right. Patients with cervical spine injury showed significant impairment of proprioception in comparison with healthy subjects (P < 0.001). The results support the hypothesis that subject with recent cervical spine injury have incorrect perception of their head position. Therefore, their rehabilitation should include the correction of proprioception and head coordination.     

Effects of abnormal posture on capsular ligament elongations in a computational model subjected to whiplash loading

Although considerable biomechanical investigations have been conducted to understand the response of the cervical spine under whiplash (rear impact-induced postero-anterior loading to the thorax), studies delineating the effects of initial spinal curvature are limited. This study advanced the hypothesis that abnormal curvatures (straight or kyphotic) of the cervical column affect spinal kinematics during whiplash loading. Specifically, compared to the normal lordotic curvature, abnormal curvatures altered facet joint ligament elongations. The quantifications of these elongations were accomplished using a validated mathematical model of the human head-neck complex that simulated three curvatures. The model was validated using companion experiments conducted in our laboratory that provided facet joint kinematics as a function of cervical spinal level. Regional facet joint ligament elongations were investigated as a function of whiplash loading in the four local anatomic regions of each joint. Under the normal posture, greatest elongations occurred in the dorsal anatomic region at the C2-C3 level and in the lateral anatomic region from C3-C4 to C6-C7 levels. Abnormal postures increased elongation magnitudes in these regions by up to 70%. Excessive ligament elongations induce laxity to the facet joint, particularly at the local regions of the anatomy in the abnormal kyphotic posture. Increased laxity may predispose the cervical spine to accelerated degenerative changes over time and lead to instability. Results from the present study, while providing quantified level- and region-specific kinematic data, concur with clinical findings that abnormal spinal curvatures enhance the likelihood of whiplash injury and may have long-term clinical and biomechanical implications.     

Whiplash injuries; diagnosis and treatment

Whiplash injury may extend far beyond the neck, and may involve even the soft tissues of the pelvis. For permanent recovery, all the injuries must be evaluated and treated together. When impact from the rear snaps the head back and then forward, posterior subluxations in the cervical spine cause anterior-posterior narrowing of the intervertebral foramina, which may result in injury to the cervical nerve roots. Impact at the front, causing hyperflexion followed by hyperextension, has a similar effect although usually not as severe. Resulting symptoms may not appear until two or three weeks later, when irritative lesions have developed because of hemorrhage or swelling. Mild or progressive degenerative changes may cause no symptoms but may predispose the affected area to injury following some slight trauma. Capsular ligaments of the lateral intervertebral joints are especially liable to whiplash injury which may give rise to scars and adhesions that compress spinal nerves. Sympathetic system involvement may cause reflex and referred pain. Detailed neurologic, roentgen and electromyographic studies may be necessary for proper evaluation of injuries. Seemingly psychosomatic pain or disability is likely to have some physical basis in whiplash injuries. In 33 patients with whiplash injury, some recently injured and some chronically disabled with persistent symptoms, good results were observed following hydromassage, hot packs, joint mobilization exercises and, in a few, cervical or pelvic traction.     

WHIPLASH INJURIES—Diagnosis and Treatment

Whiplash injury may extend far beyond the neck, and may involve even the soft tissues of the pelvis. For permanent recovery, all the injuries must be evaluated and treated together.When impact from the rear snaps the head back and then forward, posterior subluxations in the cervical spine cause anterior-posterior narrowing of the intervertebral foramina, which may result in injury to the cervical nerve roots. Impact at the front, causing hyperflexion followed by hyperextension, has a similar effect although usually not as severe. Resulting symptoms may not appear until two or three weeks later, when irritative lesions have developed because of hemorrhage or swelling. Mild or progressive degenerative changes may cause no symptoms but may predispose the affected area to injury following some slight trauma. Capsular ligaments of the lateral intervertebral joints are especially liable to whiplash injury which may give rise to scars and adhesions that compress spinal nerves. Sympathetic system involvement may cause reflex and referred pain.Detailed neurologic, roentgen and electromyographic studies may be necessary for proper evaluation of injuries. Seemingly psychosomatic pain or disability is likely to have some physical basis in whiplash injuries.In 33 patients with whiplash injury, some recently injured and some chronically disabled with persistent symptoms, good results were observed following hydromassage, hot packs, joint mobilization exercises and, in a few, cervical or pelvic traction.     

Evaluation of the intervertebral neck injury criterion using simulated rear impacts

The Intervertebral Neck Injury Criterion (IV-NIC) is based on the hypothesis that intervertebral motion beyond the physiological limit may injure spinal soft tissues during whiplash, while the Neck Injury Criterion (NIC) hypothesizes that sudden changes in spinal fluid pressure may cause neural injury. Goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to correlate IV-NIC with soft-tissue injury, determine the IV-NIC injury threshold, and compare IV-NIC and NIC. Using a bench-top apparatus, rear-impacts were simulated at 3.5, 5, 6.5, and 8 g horizontal accelerations of the T1 vertebra. Pre- and post-whiplash flexibility tests measured the soft tissue injury threshold, i.e. significant increases in the intervertebral neutral zone (NZ) or range of motion (ROM) above corresponding baseline values. Extension IV-NIC peaks correlated well with NZ and ROM increases at C0-C1 and at C3-C4 through C7-T1 (r=0.64 and 0.62 respectively, p<0.001). Average IV-NIC injury thresholds (95% confidence limits) varied among the intervertebral levels and ranged between 1.5 (1.1, 1.9) at C5-C6 and 3.4 (2.4, 4.4) at C7-T1. The NIC injury threshold was 8.7 (7.7, 9.7) m2/s2, substantially less than the proposed threshold of 15 m2/s2. Results support the use of IV-NIC for determining the cervical spine injury threshold and injury severity. Advantages of IV-NIC include the ability to predict the intervertebral level, mode, severity, and time of the cervical spine soft-tissue injury.     

Variation in emergency department use of cervical spine radiography for alert,stable trauma patients

OBJECTIVE: To, assess the emergency department use of cervical spine radiography for alert, stable adult trauma patients in terms of utilization, yield for injury and variation in practices among hospitals and physicians. DESIGN: Retrospective survey of health records. SETTING: Emergency departments of 6 teaching and 2 community hospitals in Ontario and British Columbia. PATIENTS: Consecutive alert, stable adult trauma patients seen with potential cervical spine injury between July 1, 1994, and June 30, 1995. MAIN OUTCOME MEASURES: Total number of eligible patients, referral for cervical spine radiography (overall, by hospital and by physician), presence of cervical spine injury, patient characteristics and hospitals associated with use of radiography. RESULTS: Of 6855 eligible patients, cervical spine radiography was ordered for 3979 (58.0%). Only 60 (0.9%) patients were found to have an acute cervical spine injury (fracture, dislocation or ligamentous instability); 98.5% of the radiographic films were negative for any significant abnormality. The demographic and clinical characteristics of the patients were similar across the 8 hospitals, and no cervical spine injuries were missed. Significant variation was found among the 8 hospitals in the rate of ordering radiography (p < 0.0001), from a low of 37.0% to a high of 72.5%. After possible differences in case severity and patient characteristics at each hospital were controlled for, logistic regression analysis revealed that 6 of the hospitals were significantly associated with the use of radiography. At 7 hospitals, there was significant variation in the rate of ordering radiography among the attending emergency physicians (p < 0.05), from a low of 15.6% to a high of 91.5%. CONCLUSIONS: Despite considerable variation among institutions and individual physicians in the ordering of cervical spine radiography for alert, stable trauma patients with similar characteristics, no cervical spine injuries were missed. The number of radiographic films showing signs of abnormality was extremely low at all hospitals. The findings suggest that cervical spine radiography could be used more efficiently, possibly with the help of a clinical decision rule.     

Epidemiology and Risk Factors of Cervical Spine Injury during Heating Season in the Patients with Cervical Trauma: A Cross-Sectional Study

Purpose

The purpose of this study was to describe the epidemiology of cervical spine injury in the patients with cervical trauma and analyze its associated risk factors during the special heating season in North China.

Methods

This cross-sectional study investigated predictors for cervical spine injury in cervical trauma patients using retrospectively collected data of Hebei Provincial Orthopaedic Hospital from 11/2011 to 02/2012, and 11/2012 to 02/2013. Binary logistic regression analysis was used to determine risk factors for cervical fractures/dislocations or cord injury.

Results

A total of 106 patients were admitted into this study. Of all, 34 patients (32.1%) were treated from 11/2011 to 02/2012 and 72 patients (67.9%) from 11/2012 to 02/2013. The mean age was 41.9±13.3 years old; 85 patients (80.2%) were male and 82 (77.4%) from rural areas. Eighty patients (75.5%) were caused by fall including 45 (42.5%) by severe fall (>2 m). Sixty-five patients (61.3%) of all suffered injuries to other body regions and 32 (30.2%) got head injury. Thirty-one patients (29.2%) sustained cervical cord injury with cervical fractures/dislocations. Twenty-six (83.9%) of cervical cord injury patients were from rural areas and 24 (77.4%) of those resulted from fall including 15 (48.4%) from severe fall (>2 m). Logistic regression displayed that age (OR, 1.47; 95% CI, 1.05–2.07), head injury (OR, 5.63; 95% CI, 2.23–14.26), were risk factors for cervical cord injury and snowing (OR, 8.25; 95% CI, 2.26–30.15) was a risk factor for cervical spine injury due to severe fall (>2 m).

Conclusions

The elder male patients and patients with head trauma are high-risk population for cervical cord injury. As a seasonal factor, snowing during heating season is of note a risk factor for cervical spine injury resulting from severe fall (>2 m) in the patients with cervical trauma in North China.     

The temporal development of fatty infiltrates in the neck muscles following whiplash injury: an association with pain and posttraumatic stress

BACKGROUND: Radiological findings associated with poor recovery following whiplash injury remain elusive. Muscle fatty infiltrates (MFI) in the cervical extensors on magnetic resonance imaging (MRI) in patients with chronic pain have been observed. Their association with specific aspects of pain and psychological factors have yet to be explored longitudinally. MATERIALS AND FINDINGS: 44 subjects with whiplash injury were enrolled at 4 weeks post-injury and classified at 6 months using scores on the Neck Disability Index as recovered, mild and moderate/severe. A measure for MFI and patient self-report of pain, loss of cervical range of movement and posttraumatic stress disorder (PTSD) were collected at 4 weeks, 3 months and 6 months post-injury. The effects of time and group and the interaction of time by group on MFI were determined. We assessed the mediating effect of posttraumatic stress and cervical range of movement on the longitudinal relationship between initial pain intensity and MFI. There was no difference in MFI across all groups at enrollment. MFI values increased in the moderate/severe group and were significantly higher in comparison to the recovered and mild groups at 3 and 6 months. No differences in MFI values were found between the mild and recovered groups. Initial severity of PTSD symptoms mediated the relationship between pain intensity and MFI at 6 months. Initial ROM loss did not. CONCLUSIONS: MFI in the cervical extensors occur soon following whiplash injury and suggest the possibility for the occurrence of a more severe injury with subsequent PTSD in patients with persistent symptoms.     

Patterns of Cervical Spine Injury and Their Associated Lesions

Motorcycle riding and diving into shallow water continue to present a high risk of cervical spine injury, often complicated by spinal cord damage. In patients with high cervical cord trauma, differentiation of arterial hypotension due to losing vasomotor control from the effects of internal hemorrhage can cause difficulty. In a series of 123 consecutive cases of cervical spine injury, no evidence was found that either early surgical treatment or steroid administration exert a favorable influence on recovery from traumatic myelopathy. When compared with other series, differences were found in the nature, frequency and severity of both spinal and associated injuries, resulting from the relative frequency among the population studied of trauma due to a particular mechanism—traffic accident, diving, industrial injury—and the special functions and location of the hospital from which information is gathered.     

Evaluation of the cerebral hemodynamic response to rhythmic handgrip.

The response of the cerebral circulation to exercise has been studied with transcranial Doppler ultrasound (TCD) because this modality provides continuous measurements of blood velocity and is well suited for the exercise environment. The use of TCD as an index of cerebral blood flow, however, requires the assumption that the diameter of the insonated vessel is constant. Here, we examine this assumption for rhythmic handgrip using a spectral index designed to measure trends in vessel flow. Nineteen normal subjects were studied during 5 min of volitional maximum rhythmic right handgrip at 1 Hz. TCD velocities from both middle arteries (left and right), blood pressure, and end-tidal PCO(2) were recorded every 10 s. A spectral weighted sum was also calculated as a flow index (FI). Averages were computed from the last 2 min of handgrip. Relative changes in velocity, FI, and pressure were calculated. The validity of FI was tested by comparing the change in diameter derived from equations relating flow and diameter. Mean blood pressure increased 23.8 +/- 17.8% (SD), and velocity increased 13.3 +/- 9.8% (left) and 9.6 +/- 8.3% (right). Although the mean change in FI was small [2.0 +/- 18. 2% (left) and 4.7 +/- 29.7% (right)], the variation was high: some subjects showed a significant increase in FI and others a significant decrease. Diameter estimates from two equations relating flow and luminal area were not significantly different. Decreases in FI were associated with estimated diameter decreases of 10%. Our data suggest that the cerebral blood flow (CBF) response to rhythmic handgrip is heterogeneous and that middle cerebral artery flow can decrease in some subjects, in agreement with prior studies using the Kety-Schmidt technique. We speculate that the velocity increase is due to sympathetically mediated vasoconstriction rather than a ubiquitous flow increase. Our data suggest that the use of ordinary TCD velocities to interpret the CBF response during exercise may be invalid.     

A biomechanical evaluation of whiplash using a multi-body dynamic model

This paper presents a biomechanical evaluation of whiplash injury potential during the initial extension motion of the head in a rear-end collision. A four-segment dynamic model is developed in the sagittal plane for the analysis. The model response is validated using the existing experimental data and is shown to simulate the "S-shape" kinematics of the cervical spine and the resulting dynamics observed in human and cadaver experiments. The model is then used to evaluate the effects of parameters such as collision severity, head/headrest separation, and the initial head orientation in the sagittal plane on the "S-shape" kinematics of the cervical spine and the resulting neck loads. It is shown, for example, that the cervical spine forms an "S-shape" for a range of change in speeds and that at lower and higher speeds changes the spine does not form the "S-shape." Furthermore, it is shown that the "S-shape" formation also depends on the head to headrest separation distance.     

舒血宁注射液联合倍他司汀对椎-基底动脉供血不足性眩晕症患者椎-基底动脉血流速度和氧化应激的影响

摘要 目的：观察舒血宁注射液联合倍他司汀对椎-基底动脉供血不足性眩晕症（VBIV）患者椎-基底动脉血流速度和氧化应激的影响。方法：纳入河北北方学院附属第一医院神经内科2019年5月~2021年3月期间收治的91例VBIV患者,根据信封抽签法将患者分为对照组和研究组,例数分别为45例和46例。对照组、研究组患者分别接受倍他司汀、舒血宁注射液联合倍他司汀治疗,两组均治疗1个月。观察两组疗效、椎-基底动脉血流速度、氧化应激、血液流变学及药物安全性。结果：对照组（68.89%）的临床总有效率明显低于研究组（91.30%）,差异有统计学意义（P<0.05）。研究组治疗1个月后椎动脉（左侧、右侧）和基底动脉的平均血流速度高于对照组（P<0.05）。研究组治疗1个月后谷胱甘肽过氧化物酶（GSH-Px）、过氧化物歧化酶（SOD）高于对照组（P<0.05）。研究组治疗1个月后全血高切黏度（HSV）、红细胞压积（HCT）、丙二醛（MDA）、红细胞沉降率（ESR）、全血低切黏度（LSV）低于对照组（P<0.05）。治疗期间,两组均未发生明显的不良反应情况。结论：VBIV患者采用舒血宁注射液联合倍他司汀治疗,可改善椎-基底动脉血流速度和血液流变学,减轻机体氧化应激,疗效可靠。     

A new acceleration apparatus for the study of whiplash with human cadaveric cervical spine specimens

The biomechanics of whiplash is often studied using cadaveric cervical spine specimens. One of the most important points in this kind of study is to create realistic loading conditions. The aim of the present project therefore was to develop an acceleration apparatus, which allows the study of whiplash with human cadaveric cervical spine specimens under as realistic loading conditions as possible. The new acceleration apparatus mainly consisted of a sled, a pneumatic acceleration unit and a railtrack and offered several unique features to create more realistic loading conditions. Among these features, the possibility to simulate the passive movements of the trunk is of capital importance. In this new apparatus, first, the general feasibility of whiplash experiments was studied, second, the reproducibility of the impacts was quantified and third, the effect of simulated movements of the trunk on accelerations and loads was examined. In the new acceleration apparatus various types of collisions could reproducibly be simulated. Simulated passive movements of the trunk strongly influenced the loading pattern of the neck. Without pivoting a steep increase of all loading parameters could be observed. This increase was less pronounced if pivoting was allowed. In conclusion, biomechanical aspects of whiplash could reproducibly be examined in the new acceleration apparatus. Due to its significant effects on the loading of the neck, pivoting of the trunk should always be taken into account in future experiments on the biomechanics of whiplash in which isolated cervical spine specimens are used.     

Abnormalities of the Vertebrobasilar Circulation due to Subclavian Artery Disease

The studies of Hutchinson and Yates on caroticovertebral stenosis have stimulated further interest in cerebrovascular disease. As a consequence, investigation of the four vessels, supplying the brain is now routine in the assessment of patients being considered for surgery for occlusive disease of the vessels. This has led to some interesting and unexpected findings.The effect of subclavian artery disease on the vertebrobasilar circulation was studied in two patients. Angiography showed the vertebral arteries to function as a collateral pathway when an occlusion of the subclavian artery was present proximal to the origin of the vertebral arteries. In one case both the carotid and the vertebral arteries were implicated in the collateral supply. A normal circulation was restored by subclavian endarterectomy.Studies of other workers have shown that such a circulation may reduce the cerebral blood flow by about 40%, but neither patient described in this report had signs or symptoms of cerebrovascular disease. It is evident that our understanding of the effects of cerebrovascular disease is far from complete.     

X-ray signs of ligamentous cervical injuries from joint manual therapy

X-ray study was conducted in 40 patients undergoing joint manual therapy (MT) to study its impact on the ligamentous apparatus of the cervical spine. The patients who had received rotational manual therapeutic techniques were found to have statodynamic dysfunction (100%), x-ray signs of ligamentous cervical injury (62%), or intervertebral disk protrusions (67%). An algorithm for cervical spine x-ray study in the frontal and lateral projections was compiled to perform after MT in the early and late periods.     

Which patients are likely to die in an accident and emergency department?

Four hundred and eighty-eight deaths occurring in an accident and emergency department over five years were analysed. Their causes were categorised as medical, surgical, or traumatic. Medical causes accounted for 87% of the deaths, of which 60% were from cardiac conditions. Blood loss was an important factor in over half the deaths from surgical and traumatic causes. Lives might have been saved by considering infectious disease in patients with medical conditions and by undertaking more rapid blood transfusion, earlier chest drainage, and lateral cervical spine x rays in appropriate surgical or traumatic cases. The admission to casualty departments of people with terminal neoplasms should be discouraged. The management of medical emergencies should be emphasised when training accident and emergency department staff.     

Factors influencing recovery from headache after common whiplash.

OBJECTIVE--To assess the relation between pretraumatic and trauma related headache in patients suffering from whiplash. DESIGN--Follow up study of patients examined a mean (SD) of 7.4 (4.2) days after trauma and again at three and six months. SETTING--Patients referred from primary care. SUBJECTS--117 patients (mean age 30.8 (9.5) years. MAIN OUTCOME MEASURES--Prevalence of trauma related headache and the predictive relation by multiple logistic regression between different somatic and psychological variables and trauma related headache at each examination. RESULTS--Prevalence of trauma related headache decreased from 57% to 27%. History of pretraumatic headache proved a significant risk factor for presenting with trauma related headache. A significant relation between trauma related headache and the following variables was found: at seven days the initial wellbeing score, early onset of neck pain, depression scale from the personality inventory, and the initial intensity of neck pain; at three months, intensity of neck pain, and history of pretraumatic headache; and at six months neck pain, pain intensity, and history of pretraumatic headache. CONCLUSIONS--History of pretraumatic headache significantly increases the likelihood of presenting with trauma related headache but only in combination with findings indicative of clinically important injury to the cervical spine.