Head position and impact direction in whiplash injuries: associations with MRI-verified lesions of ligaments and membranes in the upper cervical spine

Cervical facet capsular ligament mechanics: Estimations based on subject-specific anatomy and kinematics

Background

To understand the facet capsular ligament's (FCL) role in cervical spine mechanics, the interactions between the FCL and other spinal components must be examined. One approach is to develop a subject-specific finite element (FE) model of the lower cervical spine, simulating the motion segments and their components' behaviors under physiological loading conditions. This approach can be particularly attractive when a patient's anatomical and kinematic data are available.

Methods

We developed and demonstrated methodology to create 3D subject-specific models of the lower cervical spine, with a focus on facet capsular ligament biomechanics. Displacement-controlled boundary conditions were applied to the vertebrae using kinematics extracted from biplane videoradiography during planar head motions, including axial rotation, lateral bending, and flexion-extension. The FCL geometries were generated by fitting a surface over the estimated ligament-bone attachment regions. The fiber structure and material characteristics of the ligament tissue were extracted from available human cervical FCL data. The method was demonstrated by application to the cervical geometry and kinematics of a healthy 23-year-old female subject.

Results

FCL strain within the resulting subject-specific model were subsequently compared to models with generic: (1) geometry, (2) kinematics, and (3) material properties to assess the effect of model specificity. Asymmetry in both the kinematics and the anatomy led to asymmetry in strain fields, highlighting the importance of patient-specific models. We also found that the calculated strain field was largely independent of constitutive model and driven by vertebrae morphology and motion, but the stress field showed more constitutive-equation-dependence, as would be expected given the highly constrained motion of cervical FCLs.

Conclusions

The current study provides a methodology to create a subject-specific model of the cervical spine that can be used to investigate various clinical questions by coupling experimental kinematics with multiscale computational models.

Quantitative cervical spine injury responses in whiplash loading with a numerical method of natural neural reflex consideration

BACKGROUND AND OBJECTIVE

Neural reflex is hypothesized as a regulating step in spine stabilizing system. However, neural reflex control is still in its infancy to consider in the previous finite element analysis of head-neck system for various applications. The purpose of this study is to investigate the influences of neural reflex control on neck biomechanical responses, then provide a new way to achieve an accurate biomechanical analysis for head-neck system with a finite element model.

METHODS

A new FE head-neck model with detailed active muscles and spinal cord modeling was established and globally validated at multi-levels. Then, it was coupled with our previously developed neuromuscular head-neck model to analyze the effects of vestibular and proprioceptive reflexes on biomechanical responses of head-neck system in a typical spinal injury loading condition (whiplash). The obtained effects were further analyzed by comparing a review of epidemiologic data on cervical spine injury situations.

RESULT

The results showed that the active model (AM) with neural reflex control obviously presented both rational head-neck kinematics and tissue injury risk referring to the previous experimental and epidemiologic studies, when compared with the passive model (PM) without it. Tissue load concentration locations as well as stress/strain levels were both changed due to the muscle activation forces caused by neural reflex control during the whole loading process. For the bony structures, the AM showed a peak stress level accounting for only about 25% of the PM. For the discs, the stress concentrated location was transferred from C2-C6 in the PM to C4-C6 in the AM. For the spinal cord, the strain concentrated locations were transferred from C1 segment to around C4 segment when the effects of neural reflex control were implemented, while the gray matter and white matter peak strains were reduced to 1/3 and 1/2 of the PM, respectively. All these were well correlated with epidemiological studies on clinical cervical spine injuries.

CONCLUSION

In summary, the present work demonstrated necessity of considering neural reflex in FE analysis of a head-neck system as well as our model biofidelity. Overall results also verified the previous hypothesis and further quantitatively indicated that the muscle activation caused by neural reflex is providing a protection for the neck in impact loading by decreasing the strain level and changing the possible injury to lower spinal cord level to reduce injury severity.

Biomechanics of the upper cervical spine ligaments in axial rotation and flexion-extension: Considerations into the clinical framework

Context:

The motion of the upper cervical spine (UCS) has a great interest for analyzing the biomechanical features of this joint complex, especially in case of instability. Although investigators have analyzed numerous kinematics and musculoskeletal characteristics, there are still little data available regarding several suboccipital ligaments such as occipito-atlantal, atlantoaxial, and cruciform ligaments.

Objective:

The aim of this study is to quantify the length and moment arm magnitudes of suboccipital ligaments and to integrate data into specific 3D-model, including musculoskeletal and motion representation.

Materials and Methods:

Based on a recent method, suboccipital ligaments were identified using UCS anatomical modeling. Biomechanical characteristics of these anatomical structures were assessed for sagittal and transversal displacements regarding length and moment arm alterations.

Results:

Outcomes data indicated length alterations >25% for occipito-atlantal, atlanto-axial and apical ligaments. The length alteration of unique ligaments was negligible. Length variation was dependent on the motion direction considered. Regarding moment arm, larger magnitudes were observed for posterior ligaments, and consistent alteration was depicted for these structures.

Conclusion:

These outcomes supply relevant biomechanical characteristics of the UCS ligaments in flexion-extension and axial rotation by quantifying length and moment arm magnitude. Moreover, 3D anatomical modeling and motion representation can help in the process of understanding of musculoskeletal behaviors of the craniovertebral junction.

Inter-examiner reliability of radiographic measurements from Open-mouth lateral bending cervical radiographs

Background

Following head and neck trauma, the involvement of the cranio-cervical junction (CCJ) and its contribution to a patients transition to chronic pain, is poorly understood. The detection of hypermobility in this region is dependent on clinical examination and static imaging modalities such as x-ray, CT and MRI. Sagittal plane hypermobility of the CCJ is evaluated using saggital view, flexion-extension cervical radiographs. Frontal plane hypermobility is typically assessed using lateral bending and open mouth cervical radiographs. Unfortunately there is no established reliability surrounding the use of these measures. This study explores the reliability of radiographic measurements of lateral-bending open-mouth cervical radiographs.

Methods

Cervical open-mouth lateral-bending X-ray images were collected from 56 different patients between 18 and 60 years of age patients following cervical spine injury. These images were interpreted by two musculoskeletal radiologists and two clinicians (physiatrist and chiropractor), using a standard set of measurements. Measurements included qualitative and quantitative assessments of the amount of asymmetry noted between various osseous landmarks. Reliability statistics were calculated for levels of agreement using kappa coefficients (κ) and Intraclass Correlation Coefficients (ICC) for dichotomous and continuous variables, respectively.

Results

Reliability (κ) for qualitative assessments were moderate to substantial for asymmetry of neutral C2 spinous position, dens-lateral mass spacing, and “step off” between the lateral borders of the articular pillars of C2 and C1 lateral mass (κ range = .47–.78). ICC values for the quantitative measurements of dens-lateral mass spacing and “step off” between the lateral borders of the C2 articular pillars and C1 lateral mass were moderate to excellent (ICC range = .56–.97).

Conclusions

The qualitative and quantitative measurements used in this study demonstrated good to excellent inter-examiner reliability. Correlation with clinical findings is necessary to establish the utility of these measurements in clinical practice.

Imaging of cranio-cervical junction traumas

The craniocervical junction (CCJ) or upper cervical spine (UCS) has anatomic features and a biomechanics completely different from the other spinal segment of the spine. Several ligaments and muscles control its motion and function and ensure the maximum mobility and the visual and auditory spatial exploration. UCS traumas represent approximately one-third of all cervical spine injuries. Most of UCS traumas results from blows to the head and sudden deceleration of the body. Thanks to the improvement of the Advanced Trauma Life Support protocols dissociative injuries of CCJ have become less lethal onsite. In other less severe but unstable injuries, patients are neurologically intact at presentation, but they may deteriorate during the stay in hospital, with important clinical and medico-legal consequences. Knowing the peculiarities of UCS is fundamental for the early detection of imaging findings that influences the patient management and outcome. The classification of UCS traumas is mechanistic. More than in any other spinal segment, fractures of CCJ bones can occur without generating instability; on the contrary highly unstable injuries may not be associated with bone fractures. An early and correct diagnosis of occipito-cervical instability may prevent secondary neurological injury. The goal of imaging is to identify which patients can benefit of surgical stabilization and prevent secondary neurologic damage. Actual helical multidetector-CT (MDCT) offers high sensitivity and specificity for bone lesions and displacements in cervical spine traumas, but magnetic resonance imaging (MRI) is increasingly being used to evaluate soft tissues and ligaments, and mainly to identify possible spinal cord injury.

Head postures during naturalistic driving

OBJECTIVE

A rotated head posture at the time of a rear-end impact is associated with a higher risk of acute and chronic whiplash injury. The objective of this study was to quantify the amplitude and duration of rotated head postures observed in drivers during naturalistic driving.

METHODS

Twenty volunteers (14 males: 36 ± 12 years, 6 females: 27 ± 5 years) drove a 2010 Subaru Impreza on public roads while their 3D head angular position relative to the car was recorded using inertial measurement units. An experimenter rode in the passenger seat (right side) and logged when subjects performed one of 6 head movements: Bilateral shoulder and side mirror checks, looking at the rearview mirror, and looking at the front seat passenger. Video of the subjects was used to confirm the logged head movements and identify movements that the experimenter missed. The duration and amplitude of all 6 head movements were tabulated and then compared between periods when the car was moving and when the car was stationary.

RESULTS

During a 68 ± 5-min drive, subjects performed a median (range) of 15 (5-39) left shoulder checks, 82.5 (29-167) left mirror checks, 40.5 (10-168) rearview mirror checks, 27.5 (3-113) right mirror checks, 60 (0-185) passenger looks, and 12.5 (1-28) right shoulder checks. Peak yaw angles of the head relative to the vehicle for these 6 movements averaged -81.5°, -34.3°, 16.2°, 42.1°, 58.2°, and 84.3°, respectively. Drivers spent a larger proportion of time in nonneutral postures when the vehicle was stopped (17.5%) compared to moving (8.2%) (Z = 3.92, P < .0001). Drivers also moved their head further from neutral during the movements when the car was stationary compared to moving (t₁₉ = 5.90, P < .0001).

CONCLUSIONS

Drivers use larger and longer duration head movements when stationary than when driving. Given an increased risk of whiplash injury for initially rotated head postures, these findings provide a possible explanation for why drivers are more likely to be injured when hit from behind while their vehicle is stationary. Further, the head postures characterized in this study can be used as initial conditions in volunteer and computational studies to improve our understanding of why nonneutral head postures are associated with increased whiplash injury risk.

Investigation of the Effect of Neck Muscle Active Force on Whiplash Injury of the Cervical Spine

The objective of the present study is to investigate the influence of neck muscle activation on whiplash neck injury of the occupants of a passenger vehicle under different severities of frontal and rear-end impact collisions. The finite element (FE) model has been used as a versatile tool to simulate and understand the whiplash injury mechanism for occupant injury prevention. However, whiplash injuries and injury mechanisms have rarely been investigated in connection with neck active muscle forces, which restricts the complete reappearance and understanding of the injury mechanism. In this manuscript, a mixed FE human model in a sitting posture with an active head-neck was developed. The response of the cervical spine under frontal and rear-end collision conditions was then studied using the FE model with and without neck muscle activation. The effect of the neck muscle activation on the whiplash injury was studied based on the results of the FE simulations. The results indicated that the neck active force influenced the head-neck dynamic response and whiplash injury during a collision, especially in a low-speed collision.

An Integrated Model of Chronic Whiplash-Associated Disorder

Synopsis The development of persistent symptoms following whiplash injury from a motor vehicle collision is common and contributes substantially to societal and personal costs. The popular Quebec Task Force classification system of whiplash-associated disorders (WADs) was meant to function as a prognostic and intervention decision aid, but its usefulness has been questioned. Emerging evidence highlights the heterogeneity of WAD by demonstrating physical and psychological impairments that are unique to those who develop persistent symptoms. These impairments are not recognized in the Quebec Task Force classification system. The purpose of this clinical commentary is to describe an integrated model that focuses on how psychological and neurobiological factors interact with, and are influenced by, existing personal and environmental factors to contribute to the development of chronic WAD. The model has been developed through more than 20 years of work in the field, consultation with experts, in-depth synthesis of existing evidence, and new evidence from the authors' own research programs. A subtheme is that a point of convergence currently exists between the psychological, physiological, and social determinants of health literature that can further explain the complex presentation of WAD. The new model is proposed to orient future research toward more interdisciplinary efforts across nontraditional fields, including data scientists and consumers, to clarify the WAD condition. J Orthop Sports Phys Ther 2017;47(7):462-471. Epub 16 Jun 2017. doi:10.2519/jospt.2017.7455.

Neck Pain: Revision 2017

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these revised clinical practice guidelines is to review recent peer-reviewed literature and make recommendations related to neck pain. J Orthop Sports Phys Ther. 2017;47(7):A1-A83. doi:10.2519/jospt.2017.0302.

Out-of-Position Rear Impact Tissue-Level Investigation Using Detailed Finite Element Neck Model

OBJECTIVE

Whiplash injuries can occur in automotive crashes and may cause long-term health issues such as neck pain, headache, and visual and auditory disturbance. Evidence suggests that nonneutral head posture can significantly increase the potential for injury in a given impact scenario, but epidemiological and experimental data are limited and do not provide a quantitative assessment of the increased potential for injury. Although there have been some attempts to evaluate this important issue using finite element models, none to date have successfully addressed this complex problem.

METHODS

An existing detailed finite element neck model was evaluated in nonneutral positions and limitations were identified, including musculature implementation and attachment, upper cervical spine kinematics in axial rotation, prediction of ligament failure, and the need for repositioning the model while incorporating initial tissue strains. The model was enhanced to address these issues and an iterative procedure was used to determine the upper cervical spine ligament laxities. The neck model was revalidated using neutral position impacts and compared to an out-of-position cadaver experiment in the literature. The effects of nonneutral position (axial head rotation) coupled with muscle activation were studied at varying impact levels.

RESULTS

The laxities for the ligaments of the upper cervical spine were determined using 4 load cases and resulted in improved response and predicted failure loads relative to experimental data. The predicted head response from the model was similar to an experimental head-turned bench-top rear impact experiment. The parametric study identified specific ligaments with increased distractions due to an initial head-turned posture and the effect of active musculature leading to reduced ligament distractions.

CONCLUSIONS

The incorporation of ligament laxity in the upper cervical spine was essential to predict range of motion and traumatic response, particularly for repositioning of the neck model prior to impact. The results of this study identify a higher potential for injury in out-of-position rear collisions and identified at-risk locations based on ligament distractions. The model predicted higher potential for injury by as much as 50% based on ligament distraction for the out-of-position posture and reduced potential for injury with muscle activation. Importantly, this study demonstrated that the location of injury or pain depends on the initial occupant posture, so that both the location of injury and kinematic threshold may vary when considering common head positions while driving.

Chronic neck pain: making the connection between capsular ligament laxity and cervical instability

The use of conventional modalities for chronic neck pain remains debatable, primarily because most treatments have had limited success. We conducted a review of the literature published up to December 2013 on the diagnostic and treatment modalities of disorders related to chronic neck pain and concluded that, despite providing temporary relief of symptoms, these treatments do not address the specific problems of healing and are not likely to offer long-term cures. The objectives of this narrative review are to provide an overview of chronic neck pain as it relates to cervical instability, to describe the anatomical features of the cervical spine and the impact of capsular ligament laxity, to discuss the disorders causing chronic neck pain and their current treatments, and lastly, to present prolotherapy as a viable treatment option that heals injured ligaments, restores stability to the spine, and resolves chronic neck pain. The capsular ligaments are the main stabilizing structures of the facet joints in the cervical spine and have been implicated as a major source of chronic neck pain. Chronic neck pain often reflects a state of instability in the cervical spine and is a symptom common to a number of conditions described herein, including disc herniation, cervical spondylosis, whiplash injury and whiplash associated disorder, postconcussion syndrome, vertebrobasilar insufficiency, and Barré-Liéou syndrome. When the capsular ligaments are injured, they become elongated and exhibit laxity, which causes excessive movement of the cervical vertebrae. In the upper cervical spine (C0-C2), this can cause a number of other symptoms including, but not limited to, nerve irritation and vertebrobasilar insufficiency with associated vertigo, tinnitus, dizziness, facial pain, arm pain, and migraine headaches. In the lower cervical spine (C3-C7), this can cause muscle spasms, crepitation, and/or paresthesia in addition to chronic neck pain. In either case, the presence of excessive motion between two adjacent cervical vertebrae and these associated symptoms is described as cervical instability. Therefore, we propose that in many cases of chronic neck pain, the cause may be underlying joint instability due to capsular ligament laxity. Currently, curative treatment options for this type of cervical instability are inconclusive and inadequate. Based on clinical studies and experience with patients who have visited our chronic pain clinic with complaints of chronic neck pain, we contend that prolotherapy offers a potentially curative treatment option for chronic neck pain related to capsular ligament laxity and underlying cervical instability.

Finite element modeling of potential cervical spine pain sources in neutral position low speed rear impact

The rate of soft tissue sprain/strain injuries to the cervical spine and associated cost continue to be significant; however, the physiological nature of this injury makes experimental tests challenging while aspects such as occupant position and musculature may contribute to significant variability in the current epidemiological data. Several theories have been proposed to identify the source of pain associated with whiplash. The goal of this study was to investigate three proposed sources of pain generation using a detailed numerical model in rear impact scenarios: distraction of the capsular ligaments; transverse nerve root compression through decrease of the intervertebral foramen space; and potential for damage to the disc based on the extent of rotation and annulus fibre strain. There was significant variability associated with experimental measures, where the range of motion data overlapped ultimate failure data. Average data values were used to evaluate the model, which was justified by the use of average mechanical properties within the model and previous studies demonstrating predicted response and failure of the tissues was comparable to average response values. The model predicted changes in dimension of the intervertebral foramen were independent of loading conditions, and were within measured physiological ranges for the impact severities considered. Disc response, measured using relative rotation between intervertebral bodies, was below values associated with catastrophic failure or avulsion but exceeded the average range of motion values. Annulus fibre strains exceeded a proposed threshold value at three levels for 10g impacts. Capsular ligament strain increased with increasing impact severity and the model predicted the potential for injury at impact severities from 4g to 15.4g, when the range of proposed distraction corresponding to sub-catastrophic failure was exceeded, in agreement with the typically reported values of 9-15g. This study used an enhanced neck finite element model with active musculature to investigate three potential sources of neck pain resulting from rear impact scenarios and identified capsular ligament strain and deformation of the disc as potential sources of neck pain in rear impact scenarios.

Investigating cervical muscle response and head kinematics during right, left, frontal and rear-seated perturbations

OBJECTIVE

Whiplash research has largely focused on rear collisions because they account for the majority of whiplash injuries. The purpose of this study was to evaluate the effects of 4 perturbation directions (anterior, posterior, right, and left) on muscle activity and head kinematics to provide insight into the whiplash mechanism of injury.

METHODS

The effects of 4 perturbation directions induced by a parallel robotic platform, with peak acceleration of 8.50 m/s2, were analyzed on 10 subjects. Surface electromyography (EMG) measures were collected from the sternocleidomastoid (SCM), trapezius, and splenius capitus muscles. Kinematics of the head, thorax, and head relative to thorax were also measured.

RESULTS

We observed stereotypic responses for kinematics and SCM EMG for the various perturbation directions; the trapezius and splenius capitus muscles showed amplitudes that were less than 5 percent maximum voluntary contraction (MVC). Rear perturbations elicited the smallest onset latencies for the SCM (30 ms) and kinematic variables and greatest linear head center of mass (COM) accelerations. Frontal perturbations resulted in an average SCM onset latency of 143 ms and demonstrated the greatest magnitude of head translations and rotations relative to the thorax. Left and right perturbations demonstrated similar kinematics and SCM onset latencies (55 and 65 ms, respectively).

CONCLUSIONS

Compared to frontal, left, and right directions, rear perturbations showed smaller SCM onset latencies, greater SCM amplitudes, and larger head accelerations, relating to a greater potential for injury. We suggest that the greater contact area and stiffness of the seatback, in the posterior direction, compared to restrictions in other directions, led to increased peak head accelerations and shorter SCM onset latencies.

Mechanisms of chronic pain from whiplash injury

This article is to provide insights into the mechanisms underlying chronic pain from whiplash injury. Studies show that injury produces plasticity changes of different neuronal structures that are responsible for amplification of nociception and exaggerated pain responses. There is consistent evidence for hypersensitivity of the central nervous system to sensory stimulation in chronic pain after whiplash injury. Tissue damage, detected or not by the available diagnostic methods, is probably the main determinant of central hypersensitivity. Different mechanisms underlie and co-exist in the chronic whiplash condition. Spinal cord hyperexcitability in patients with chronic pain after whiplash injury can cause exaggerated pain following low intensity nociceptive or innocuous peripheral stimulation. Spinal hypersensitivity may explain pain in the absence of detectable tissue damage. Whiplash is a heterogeneous condition with some individuals showing features suggestive of neuropathic pain. A predominantly neuropathic pain component is related to a higher pain/disability level.

Cervical status after neck sprains in frontal and rear-end car impacts

OBJECTIVE

To compare the cervical status after neck sprains in frontal and rear-end car impacts with respect to earlier proposed neck-sprain injury mechanisms, rotated head at impact, and the seat-belt geometry.

METHODS

A prospective, multidisciplinary, in-depth study was made based on 23 car occupants injured in frontal impacts and 108 injured in rear-end impacts. The active neck mobility was measured in protraction-retraction, flexion-extension, side bending right-left, and rotation right-left. This was done in the acute phase and then three and twelve months later. The maximum range, increase in pain, and level of pain were recorded for each movement. A subgroup with increased pain during movements towards the impact direction, but not in the opposite one, so-called isolated contra-directional pain (ICP), was further analysed. The side bending and rotation mobility were studied in another subgroup, in which the head was rotated inwards or outwards relative the car, i.e. away from or towards the diagonal part of the seat belt.

RESULTS

Rear-end impacts more often than frontal impacts caused greater restrictions of the cervical mobility and more frequently increased pain at the three different times that measurements were recorded, but, with few exceptions, the differences for each movement were not statistically significant. Increased pain during extension was more often noted after rear-end impacts. ICP during pro-/retraction was also more often noted after rear-end impacts. Head-inward rotation in rear-end impacts caused a more restricted mobility in the same direction at the primary examination than head-outward rotation.

CONCLUSIONS

The cervical status after neck sprains in frontal and rear-end car impacts is very similar, and the cervical range of movement in different directions and increased pain during cervical motions do not reveal any specific isolated injury mechanisms. Combined injury mechanisms should be considered, and further studies are recommended to investigate asymmetric loading during impact.

The influence of morphology on cervical injury characteristics

STUDY DESIGN

Review of peer-reviewed literature.

OBJECTIVE

Outline the effects of neck and cervical spine morphology on soft tissue injury Potential during low velocity automotive rear impacts.

SUMMARY OF BACKGROUND DATA

Automotive rear impacts are mechanical events and the response of the human head-neck complex can be thought of in biomechanical terms. This manuscript reviews evidence from peer-reviewed studies implicating occupant-related factors in the onset and severity of cervical spine soft-tissue injury.

METHODS

Effects of anatomical characteristics, head-neck and spine orientation, facet joints, and neck muscles were reviewed.

RESULTS

On the basis of existing biomechanically based research, the following occupant-related characteristics can influence the response of the cervical spine during automotive rear impacts: anatomical dimensions of the cervical spine, head-neck and cervical spine orientation at the time of impact, facet joint orientation, and neck muscle size and orientation.

CONCLUSION

The response of the cervical spine to rear impacts can be described using biomechanical concepts. This review has identified occupant-related factors that can influence injury susceptibility and cited biomechanically related research to outline the method by which those factors affect the overall head-neck and cervical spine response in such a way as to increase the susceptibility or severity of injury for a given rear impact event.

Preventing motor vehicle crashes related spine injuries in children

BACKGROUND

Spinal cord injury (SCI) is a devastating event that results in permanent disability for injured children. Among all etiologies of SCI, motor vehicle crashes (MVCs) are the leading cause and account for 29% of all traumatic SCIs in children. We tried to evaluate types and mechanisms of MVC-related spinal column and spinal cord injuries, risk factors, safety issues and legislation.

DATA SOURCES

A literature review was performed using PubMed from 1966 to 12th April 2010 with the following key words: children OR pediatric, spine, injury OR trauma, restraint, seat belt, motor vehicle, road OR traffic, collision OR crash, safety. Cross referencing of discovered articles was also performed.

RESULTS

Risk factors for MVC-related SCI include single vehicle crashes, vehicle rollover, and ejection of the passenger from the vehicle. Any anatomic region of the spinal cord may be injured as a result of MVC and may vary according to the type of accident and restraint system usage. Increasing use of three-point seat belts, which are more protective than isolated lap seat belts, has decreased the incidence of MVC-related SCI. There is evidence that airbag use without seatbelt use is associated with an increased risk of cervical spine fractures with or without SCI. Vehicle designers need to give more attention to the prevention of vehicle rollover and to improve occupant protection when rollover occurs.

CONCLUSIONS

MVC is a common cause of SCI in children; therefore, paying attention to risk factors and modes of prevention is important. As MVC-related SCI can lead to permanent disability, prevention and education play an important role in decreasing childrens' morbidity and mortality. Making behavior, roads and vehicles safer can significantly reduce MVC-related SCI in children.

Occult hypermobility of the craniocervical junction: a case report and review

STUDY DESIGN

Resident's case problem.

BACKGROUND

Patients often present to physical therapists with chief complaints of neck pain, occipital headache, and dizziness associated with a past history of cervical spine injury. These symptoms may be associated with various cervical spine conditions, including craniocervical junction (CCJ) hypermobility.

DIAGNOSIS

This report reviews the history, physical exam, and diagnostic imaging findings of a patient with the above symptoms. This patient, who had a history of multiple cervical spine injuries, was examined with 2 manual therapy provocative tests: the Sharp-Purser test, which is intended to stress the transverse ligament and odontoid, and the modified lateral shear test, which is intended to stress the alar ligaments. The lateral shear test was perceived as demonstrating excessive mobility and a soft end feel, with a "shift" of C1 on C2. Stress cervical radiographs, obtained using open-mouth projections in neutral, left, and right cervical lateral flexion, revealed a 3-mm lateral offset of the right lateral mass of C1 on C2. MRI evaluation of the lower cervical spine did not reveal any significant disc derangement; however, images of the soft tissues of the craniocervical junction were not obtained. Based on the examination and imaging studies, the patient was determined to have a previously undiagnosed hypermobility of the atlantoaxial joint.

DISCUSSION

The patient was advised to avoid rotational manipulation and end range lateral flexion stretching exercises. Axial traction manipulation techniques, midrange stabilization exercises, and postural advice appeared to provide good relief of symptoms. Physical therapists should consider the possibility of CCJ hypermobility in the frontal plane when examining the cervical spine in patients with chronic neck pain, headache, and a past history of trauma. The lateral shear test and stress radiography may provide simple screening tests for occult CCJ hypermobility; however, the reliability and validity of these tests is lacking. Further research on diagnosis and management of CCJ hypermobility is warranted.

LEVEL OF EVIDENCE

Differential diagnosis, level 4.

Magnetic resonance imaging of the alar and transverse ligaments in acute whiplash-associated disorders 1 and 2: a cross-sectional controlled study

STUDY DESIGN

Cross-sectional.

OBJECTIVE

To describe alar- and transverse-ligament magnetic resonance imaging (MRI) high-signal changes in acute whiplash-associated disorders (WAD) grades 1 and 2 in relation to the severity and mechanics of trauma, and to compare them with controls.

SUMMARY OF BACKGROUND DATA

The alar and transverse ligaments are important stabilizers at the craniovertebral junction. Acute injury of these ligaments should be detected as high-signal changes on high-resolution MRI.

METHODS

In the study, 114 consecutive acute WAD 1-2 patients and 157 noninjured controls underwent upper-neck high-resolution MRI, using proton-weighted sequences and Short Tau Inversion Recovery (STIR). Two blinded radiologists independently graded high-signal changes 0 to 3 on proton images and assessed ligament high-signal intensity on STIR. Image quality was evaluated as good, reduced, or poor (not interpretable). Multiple logistic regression was used for both within- and between-groups analyses.

RESULTS

All proton and STIR images were interpretable. Interobserver agreement for grades 2 to 3 versus grades 0 to 1 changes was moderate to good (κ = 0.71 alar; and 0.54 transverse). MRI showed grades 2 to 3 alar ligament changes in 40 (35.1%) and grades 2 to 3 transverse ligament changes in 27 (23.7%) of the patients. Such changes were related to contemporary head injury (P = 0.041 alar), neck pain (P = 0.042 transverse), and sex (P = 0.033 transverse) but did not differ between patients and controls (P = 0.433 alar; and 0.254 transverse). STIR ligament signal intensity, higher than bone marrow, was found in only three patients and one control.

CONCLUSION

This first study on high-resolution MRI of craniovertebral ligaments in acute WAD 1-2 indicates that such trauma does not induce high-signal changes. Follow-up studies are needed to find out whether pretraumatic high-signal changes imply reduced ligament strength and can predict chronic WAD.

Cervical spine rotation and range of motion: pilot measurements during driving

OBJECTIVE

Previous studies have evaluated the cervical range of axial rotation during simulated driving conditions. The goals of this pilot study were to describe cervical spine rotation during in-car driving and determine the percentage of time outside neutral neck rotation and peak cervical axial rotation angles that the subjects adopted during various driving conditions.

METHODS

Subjects drove around a specified route through the city of Guelph, Ontario, which included residential, thruway, and highway driving; additional minor driving tasks, such as lane changes, were also included. The cervical range of motion was measured continuously throughout the drive using an electromagnetic sensor; we also used videotape to document the specific driving tasks.

RESULTS

The subjects spent 87.0 percent (SD=8.8) of time with their cervical spine in the neutral axial rotation position (±15 degrees). The percentage of time that the subjects spent outside of the neutral range of cervical axial rotation depended upon the driving section (including residential, thruway, and highway), and driving task being performed (starts, stops, and lane changes). The subjects spent a significantly greater proportion of time with their necks rotated beyond neutral during residential driving compared to thruway and highway driving (19.1% SD=8.3 vs. 10.7% SD=9.5 and 9.3% SD=8.7, respectively; p<.001). During driving, the peak angles of cervical axial rotation were an average of 35.7 degrees (SD=14.2) left and 42.5 degrees (SD=18.0) right.

CONCLUSIONS

We observed a large degree of variability in cervical axial rotation during driving. We observed that most of the driving tasks related to stopping had increased proportion of time out of neutral rotation. Also, right-hand lane changes increased time out of neutral rotation more than left-hand lane changes. Drivers routinely adopt nonneutral head positions (on average 13% of the time); this is likely not enough to lead to injury.

Are MRI high-signal changes of alar and transverse ligaments in acute whiplash injury related to outcome?

Background

Upper neck ligament high-signal changes on magnetic resonance imaging (MRI) have been found in patients with whiplash-associated disorders (WAD) but also in non-injured controls. The clinical relevance of such changes is controversial. Their prognostic role has never been evaluated. The purpose of this study was to examine if alar and transverse ligament high-signal changes on MRI immediately following the car accident are related to outcome after 12 months for patients with acute WAD grades 1-2.

Methods

Within 13 days after a car accident, 114 consecutive acute WAD1-2 patients without prior neck injury or prior neck problems underwent upper neck high-resolution proton-weighted MRI. High-signal changes of the alar and transverse ligaments were graded 0-3. A questionnaire including the impact of event scale for measuring posttraumatic stress response and questions on patients' expectations of recovery provided clinical data at injury. At 12 months follow-up, 111 (97.4%) patients completed the Neck Disability Index (NDI) and an 11-point numeric rating scale (NRS-11) on last week neck pain intensity. Factors potentially related to these outcomes were assessed using multiple logistic regression analyses.

Results

Among the 111 responders (median age 29.8 years; 63 women), 38 (34.2%) had grades 2-3 alar ligament changes and 25 (22.5%) had grades 2-3 transverse ligament changes at injury. At 12 months follow-up, 49 (44.1%) reported disability (NDI > 8) and 23 (20.7%) neck pain (NRS-11 > 4). Grades 2-3 ligament changes in the acute phase were not related to disability or neck pain at 12 months. More severe posttraumatic stress response increased the odds for disability (odds ratio 1.46 per 10 points on the impact of event scale, p = 0.007) and so did low expectations of recovery (odds ratio 4.66, p = 0.005).

Conclusions

High-signal changes of the alar and transverse ligaments close after injury did not affect outcome for acute WAD1-2 patients without previous neck problems. High-resolution upper neck MRI has limited value for the initial examination and follow-up of such patients.

Axial head rotation increases facet joint capsular ligament strains in automotive rear impact

Axial head rotation prior to low speed automotive rear impacts has been clinically identified to increase morbidity and symptom duration. The present study was conducted to determine the effect of axial head rotation on facet joint capsule strains during simulated rear impacts. The study was conducted using a validated intact head to first thoracic vertebra (T1) computational model. Parametric analysis was used to assess effects of increasing axial head rotation between 0 and 60° and increasing impact severity between 8 and 24 km/h on facet joint capsule strains. Rear impacts were simulated by horizontally accelerating the T1 vertebra. Characteristics of the acceleration pulse were based on the horizontal T1 acceleration pulse from a series of simulated rear impact experiments using full-body post mortem human subjects. Joint capsule strain magnitudes were greatest in ipsilateral facet joints for all simulations incorporating axial head rotation (i.e., head rotation to the left caused higher ligament strain at the left facet joint capsule). Strain magnitudes increased by 47-196% in simulations with 60° head rotation compared to forward facing simulations. These findings indicate that axial head rotation prior to rear impact increases the risk of facet joint injury.

The clinical presentation of chronic whiplash and the relationship to findings of MRI fatty infiltrates in the cervical extensor musculature: a preliminary investigation

The objective was to determine whether any measurable changes in sensory responses, kinesthetic sense, cervical motion, and psychological features were related to established fatty infiltration values in the cervical extensor musculature in subjects with persistent whiplash. It is unknown if fatty infiltrate is related to any signs or symptoms. Data on motor function, Quantitative Sensory Testing, psychological and general well-being, and pain and disability were collected from 79 female subjects with chronic whiplash. Total fat values were created for all subjects by averaging the muscle fat indices by muscle, level, and side from our MRI dataset of all the cervical extensor muscles. Results of this study indicate the presence of altered physical, kinesthetic, sensory, and psychological features in this cohort of patients with chronic whiplash. Combined factors of sensory, physical, kinesthetic, and psychological features all contributed to a small extent in explaining the varying levels of fatty infiltrate, with cold pain thresholds having the most influence (r (2) = 0.28; P = 0.02). Identifying and relating quantifiable muscular alterations to clinical measures in the chronic state, underpin some clinical hypotheses for possible pathophysiological processes in this group with a chronic and recalcitrant whiplash disorder. Future research investigations aimed at accurate identification, sub-classification, prediction, and management of patients with acute and chronic whiplash is warranted and underway.

Characterization of acute and chronic whiplash-associated disorders

SYNOPSIS

The development of chronic pain and disability following whiplash injury is common and contributes substantially to personal and economic costs related with this condition. Emerging evidence demonstrates the clinical presence of alterations in the sensory and motor systems, including psychological distress in all individuals with a whiplash injury, regardless of recovery. However, individuals who transition to the chronic state present with a more complex clinical picture characterized by the presence of widespread sensory hypersensitivity, as well as significant posttraumatic stress reactions. Based on the diversity of the signs and symptoms experienced by individuals with a whiplash condition, clinicians must take into account the more readily observable/measurable differences in motor, sensory, and psychological dysfunction. The implications for the assessment and management of this condition are discussed. Further review into the pathomechanical, pathoanatomical, and pathophysiological features of the condition also will be discussed.

LEVEL OF EVIDENCE

Level 5.J

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.

Treatment of neck pain: injections and surgical interventions: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders

STUDY DESIGN

Best evidence synthesis.

OBJECTIVE

To identify, critically appraise, and synthesize literature from 1980 through 2006 on surgical interventions for neck pain alone or with radicular pain in the absence of serious pathologic disease.

SUMMARY OF BACKGROUND DATA

There have been no comprehensive systematic literature or evidence-based reviews published on this topic.

METHODS

We systematically searched Medline for literature published from 1980 to 2006 on percutaneous and open surgical interventions for neck pain. Publications on the topic were also solicited from experts in the field. Consensus decisions were made about the scientific merit of each article; those judged to have adequate internal validity were included in our Best Evidence Synthesis.

RESULTS

Of the 31,878 articles screened, 1203 studies were relevant to the Neck Pain Task Force mandate and of these, 31 regarding treatment by surgery or injections were accepted as scientifically admissible. Radiofrequency neurotomy, cervical facet injections, cervical fusion and cervical arthroplasty for neck pain without radiculopathy are not supported by current evidence. We found there is support for short-term symptomatic improvement of radicular symptoms with epidural corticosteroids. It is not clear from the evidence that long-term outcomes are improved with the surgical treatment of cervical radiculopathy compared to nonoperative measures. However, relatively rapid and substantial symptomatic relief after surgical treatment seems to be reliably achieved. It is not evident that one open surgical technique is clearly superior to others for radiculopathy. Cervical foramenal or epidural injections are associated with relatively frequent minor adverse events (5%-20%); however, serious adverse events are very uncommon (<1%). After open surgical procedures on the cervical spine, potentially serious acute complications are seen in approximately 4% of patients.

CONCLUSION

Surgical treatment and limited injection procedures for cervical radicular symptoms may be reasonably considered in patients with severe impairments. Percutaneous and open surgical treatment for neck pain alone, without radicular symptoms or clear serious pathology, seems to lack scientific support.

Assessment of neck pain and its associated disorders: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders

STUDY DESIGN

Best evidence synthesis.

OBJECTIVE

To critically appraise and synthesize the literature on assessment of neck pain.

SUMMARY OF BACKGROUND DATA

The published literature on assessment of neck pain is large and of variable quality. There have been no prior systematic reviews of this literature.

METHODS

The Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders conducted a critical review of the literature (published 1980-2006) on assessment tools and screening protocols for traumatic and nontraumatic neck pain.

RESULTS

We found 359 articles on assessment of neck pain. After critical review, 95 (35%) were judged scientifically admissible. Screening protocols have high predictive values to detect cervical spine fracture in alert, low-risk patients seeking emergency care after blunt neck trauma. Computerized tomography (CT) scans had better validity (in adults and elderly) than radiographs in assessing high-risk and/or multi-injured blunt trauma neck patients. In the absence of serious pathology, clinical physical examinations are more predictive at excluding than confirming structural lesions causing neurologic compression. One exception is the manual provocation test for cervical radiculopathy, which has high positive predictive value. There was no evidence that specific MRI findings are associated with neck pain, cervicogenic headache, or whiplash exposure. No evidence supports using cervical provocative discography, anesthetic facet, or medial branch blocks in evaluating neck pain. Reliable and valid self-report questionnaires are useful in assessing pain, function, disability, and psychosocial status in individuals with neck pain.

CONCLUSION

The scientific evidence supports screening protocols in emergency care for low-risk patients; and CT-scans for high-risk patients with blunt trauma to the neck. In nonemergency neck pain without radiculopathy, the validity of most commonly used objective tests is lacking. There is support for subjective self-report assessment in monitoring patients' course, response to treatment, and in clinical research.

MRI of the alar and transverse ligaments in whiplash-associated disorders (WAD) grades 1-2: high-signal changes by age, gender, event and time since trauma

INTRODUCTION

This study describes the prevalence of high-signal changes at magnetic resonance imaging (MRI) of the alar and transverse ligaments in whiplash-associated disorders (WAD) grades 1-2 in relation to age, gender, spinal degeneration, type of trauma event and time since trauma.

MATERIALS AND METHODS

In 1,266 consecutive WAD1-2 patients (779 women, 487 men; mean age 42 years) referred from clinicians, high-signal changes in the alar and transverse ligaments at high-resolution proton-weighted MRI were prospectively graded 0-3 based on a previously reported, reliable grading system. Type of event according to The International Statistical Classification of Diseases and Related Health Problems and time of trauma were obtained from referral letters.

RESULTS

MRI showed grades 2-3 alar ligament changes in 449 (35.5%; 95% confidence interval (CI), 32.8 to 38.1%) and grades 2-3 transverse ligament changes in 311 (24.6%; 95% CI, 22.2% to 26.9%) of the 1,266 patients. Grades 2-3 changes were more common in men than women, odds ratio 1.9 (95% CI, 1.5 to 2.5) for alar and 1.5 (95% CI, 1.1 to 2.0) for transverse ligament changes. High-signal changes were not related to age, spinal degeneration, type of trauma event or time since trauma (median 5 years). Unilateral changes were more often left- than right-sided.

CONCLUSIONS

High-signal changes of the alar and transverse ligaments are common in WAD1-2 and unlikely to represent age-dependent degeneration. Their male and left-side preponderance cannot be explained by variation in ligament stretching or image artefacts. Further studies are needed to clarify whether such changes are caused by trauma.

[Whiplash-associated disorders: a challenge for the expert in compensation claims and litigation]

In the literature, the association between chronic complaints of the cervical spine and sustained"whiplash trauma" is a matter of controversy. Whiplash trauma is identified as contusion, compression, and/or sprain without definite imaging proof of injury to the bone, disk, or ligaments.However, complex chronic complaints leading to permanent and significant functional limitations in daily living and work may develop. Besides the diagnostic and therapeutic challenges for the treating physician, the expert confronted with compensation claims very often must decide whether whiplash trauma of the spine may lead to significant and permanent functional limitations or loss with chronic disorders. The data from the literature dealing with this topic are contradictory and deficient. In this article, based on the present available data from the literature, we critically examine the causality between spinal whiplash trauma and possible permanent chronic complaints in order to support the process of decision making in cases of litigation and controversial compensation claims.

Assessment of neck pain and its associated disorders: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders

STUDY DESIGN

Best evidence synthesis.

OBJECTIVE

To critically appraise and synthesize the literature on assessment of neck pain.

SUMMARY OF BACKGROUND DATA

The published literature on assessment of neck pain is large and of variable quality. There have been no prior systematic reviews of this literature.

METHODS

The Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders conducted a critical review of the literature (published 1980-2006) on assessment tools and screening protocols for traumatic and nontraumatic neck pain.

RESULTS

We found 359 articles on assessment of neck pain. After critical review, 95 (35%) were judged scientifically admissible. Screening protocols have high predictive values to detect cervical spine fracture in alert, low-risk patients seeking emergency care after blunt neck trauma. Computerized tomography (CT) scans had better validity (in adults and elderly) than radiographs in assessing high-risk and/or multi-injured blunt trauma neck patients. In the absence of serious pathology, clinical physical examinations are more predictive at excluding than confirming structural lesions causing neurologic compression. One exception is the manual provocation test for cervical radiculopathy, which has high positive predictive value. There was no evidence that specific MRI findings are associated with neck pain, cervicogenic headache, or whiplash exposure. No evidence supports using cervical provocative discography, anesthetic facet, or medial branch blocks in evaluating neck pain. Reliable and valid self-report questionnaires are useful in assessing pain, function, disability, and psychosocial status in individuals with neck pain.

CONCLUSION

The scientific evidence supports screening protocols in emergency care for low-risk patients; and CT-scans for high-risk patients with blunt trauma to the neck. In nonemergency neck pain without radiculopathy, the validity of most commonly used objective tests is lacking. There is support for subjective self-report assessment in monitoring patients' course, response to treatment, and in clinical research.

Treatment of neck pain: injections and surgical interventions: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders

STUDY DESIGN

Best evidence synthesis.

OBJECTIVE

To identify, critically appraise, and synthesize literature from 1980 through 2006 on surgical interventions for neck pain alone or with radicular pain in the absence of serious pathologic disease.

SUMMARY OF BACKGROUND DATA

There have been no comprehensive systematic literature or evidence-based reviews published on this topic.

METHODS

We systematically searched Medline for literature published from 1980 to 2006 on percutaneous and open surgical interventions for neck pain. Publications on the topic were also solicited from experts in the field. Consensus decisions were made about the scientific merit of each article; those judged to have adequate internal validity were included in our Best Evidence Synthesis.

RESULTS

Of the 31,878 articles screened, 1203 studies were relevant to the Neck Pain Task Force mandate and of these, 31 regarding treatment by surgery or injections were accepted as scientifically admissible. Radiofrequency neurotomy, cervical facet injections, cervical fusion and cervical arthroplasty for neck pain without radiculopathy are not supported by current evidence. We found there is support for short-term symptomatic improvement of radicular symptoms with epidural corticosteroids. It is not clear from the evidence that long-term outcomes are improved with the surgical treatment of cervical radiculopathy compared to nonoperative measures. However, relatively rapid and substantial symptomatic relief after surgical treatment seems to be reliably achieved. It is not evident that one open surgical technique is clearly superior to others for radiculopathy. Cervical foramenal or epidural injections are associated with relatively frequent minor adverse events (5%-20%); however, serious adverse events are very uncommon (<1%). After open surgical procedures on the cervical spine, potentially serious acute complications are seen in approximately 4% of patients.

CONCLUSION

Surgical treatment and limited injection procedures for cervical radicular symptoms may be reasonably considered in patients with severe impairments. Percutaneous and open surgical treatment for neck pain alone, without radicular symptoms or clear serious pathology, seems to lack scientific support.

Whiplash causes increased laxity of cervical capsular ligament

BACKGROUND

Previous clinical studies have identified the cervical facet joint, including the capsular ligaments, as sources of pain in whiplash patients. The goal of this study was to determine whether whiplash caused increased capsular ligament laxity by applying quasi-static loading to whiplash-exposed and control capsular ligaments.

METHODS

A total of 66 capsular ligament specimens (C2/3 to C7/T1) were prepared from 12 cervical spines (6 whiplash-exposed and 6 control). The whiplash-exposed spines had been previously rear impacted at a maximum peak T1 horizontal acceleration of 8 g. Capsular ligaments were elongated at 1mm/s in increments of 0.05 mm until a tensile force of 5 N was achieved and subsequently returned to neutral position. Four pre-conditioning cycles were performed and data from the load phase of the fifth cycle were used for subsequent analyses. Ligament elongation was computed at tensile forces of 0, 0.25, 0.5, 0.75, 1.0, 2.5, and 5.0 N. Two factor, non-repeated measures ANOVA (P<0.05) was performed to determine significant differences in the average ligament elongation at tensile forces of 0 and 5 N between the whiplash-exposed and control groups and between spinal levels.

FINDINGS

Average elongation of the whiplash-exposed capsular ligaments was significantly greater than that of the control ligaments at tensile forces of 0 and 5 N. No significant differences between spinal levels were observed.

INTERPRETATION

Capsular ligament injuries, in the form of increased laxity, may be one component perpetuating chronic pain and clinical instability in whiplash patients.

Role of Spinal Inhibitory Mechanisms in Whiplash Injuries

Whiplash injury, commonly encountered in road traffic accidents, is a major cause of morbidity. Its pathophysiology is not well understood, and diagnosis remains clinical. Imaging and electrophysiological methods have not provided objective diagnostic evidence. Availability of a sensitive and specific diagnostic method would be of high clinical interest. We studied 20 consecutive patients with chronic whiplash injury. Despite persistent symptoms, most had minimal neurological findings. Cutaneous silent period (CSP), a nociceptive spinal inhibitory electromyographic reflex, showed 90% sensitivity and 90% specificity for its diagnosis. In contrast, only two patients (10%) had abnormal transcranial magnetic stimulation findings, and another two (10%) showed abnormal electromyography. Magnetic resonance imaging (MRI) showed cervical cord abnormalities in only two of 20 (10%) patients. None of the patients had abnormal somatosensory evoked potential studies. Our findings suggest that neurological dysfunction of whiplash may occur at several possible spinal cord localities in the CSP functional pathway. The use of this simple, quick, and sensitive method is advocated in the diagnostic work up of whiplash injury.

Incidence and outcome of whiplash injury after multiple trauma

STUDY DESIGN

A retrospective study of 101 consecutive polytrauma patients with regard to whiplash injury.

OBJECTIVES

To investigate the incidence and evaluate long-term outcome of whiplash injury following high-energy trauma.

SUMMARY OF BACKGROUND DATA

Chronic whiplash injury has been widely reported in the literature, following low-energy trauma. Very few studies exist on whiplash injury following high-energy trauma.

METHODS

A total of 101 consecutive polytrauma patients admitted to our Level I Trauma Center over a 2-year period, fulfilling the inclusion criteria (age >18 years, high-energy trauma [a fall from a height >2 m, road traffic accidents with speed >30 km/h], and Injury Severity Score >16), were assessed. Whiplash injury was defined according to Quebec Task Force guidelines. The study group (n = 13) included patients who developed whiplash injury symptoms and the control group (n = 88) those who did not. The Neck Disability Index was calculated as an outcome measure for patients complaining of whiplash injury symptoms. The mean follow-up was 17 months. The chi2 and Student t tests were used for the statistical analysis (SPSS 12.1; SPSS, Inc., Chicago, IL).

RESULTS

Only 13 out of 101 patients (1 female/12 male) (13%) complained of whiplash injury. There was a significantly higher rate of neck pain at triage (P < 0.001) and higher combined mean of Abbreviated Injury Score of upper torso (P < 0.0001) in the study group, elucidating the cause of whiplash injury. The Neck Disability Index was <24 points, indicating only mild-to-moderate disability in these patients. Whiplash injury incidence in this study (13%) was similar to the incidence of neck pain in the general population.

CONCLUSIONS

The incidence of whiplash injury following polytrauma was found to be low in our study. There is no dose-response relation between magnitude of trauma severity and incidence of whiplash injury.

Active Range of Motion as an Indicator for Ligament and Membrane Lesions in the Upper Cervical Spine after a Whiplash Trauma

In the present study, we examined whether active range of neck motion (AROM) differed between persons with and without a diagnosis of whiplash-associated disorder type 2 (WAD2) and explored whether magnetic resonance (MR)-verified lesions of specific ligaments or membranes at the craniovertebral junction was associated with increased or decreased motion in any particular direction among the WAD2 patients. A CROM goniometer was used for registration of flexion, extension, side bending (left and right) and rotation (left and right), respectively. The neck structures considered were the alar and the transverse ligaments, and the tectorial and the posterior atlanto-occipital membranes. Our study comprised 87 WAD2 patients and 29 control persons without any known neck injury. For comparing mean values of AROM between the groups, t-test and analysis of variance (ANOVA) were used. WAD patients had on average a shorter range of active motion for all movements compared with the control group. The difference was statistically significant for all measures considered, except side bending to the left. Among the WAD patients, increasing severity of lesions to the alar ligaments was associated with a decrease in maximal flexion and rotation. A similar pattern was seen for lesions to the transverse ligament, but the trend test was not significant. An abnormal posterior atlanto-occipital membrane was associated with shorter range of left rotation, with a significant trend test both in analyses with and without adjustment for lesions to other structures. No significant association was found in relation to lesions to the tectorial membrane, but very few persons had such lesions. These findings indicate that soft tissue lesions may affect neck motion as reflected by AROM. However, since lesions to different structures seem to affect the same movement, AROM alone is not a sufficient indicator for soft-tissue lesions to specific structure in the upper cervical spine.

Three-dimensional CT study on normal anatomical features of atlanto-axial joints

It has long been a research hotspot to diagnose atlanto-axial disorder by observing the shape and motions of atlanto-axial joints. The basis for correlative studies is to ascertain the normal anatomic features of atlanto-axial joints. In our study, 33 normal subjects were examined for atlanto-axial joints, by three-dimensional CT (3D-CT) in functional positions (neutral, left and right rotary position). The contraposition between superior and inferior articular facets of lateral atlanto-axial joints (AFLAJ), including its shape and type, the width of rotational facets displacement (RFD), head's rotational angle (HRA) and rotational angle at C(1-2) (RAC(1-2)) were observed and measured on 3D-CT images. In neutral position, a complete contraposition of AFLAJ was found in 25 subjects as well as a basic contraposition in 8. In rotary position, the width of RFD was between 6.16 and 8.68 mm, the angle of HRA was between 30.2 degrees and 45.8 degrees , and RAC(1-2) between 26.7 degrees and 38.9 degrees . There is no significant difference in RFD, HRA or RAC(1-2) (P > 0.05) in between levorotatory and dextrogyrate orientation, and there is a positive correlation between RFD and RAC(1-2) (r = 0.5078, P < 0.05). Our study results show that the contraposition of AFLAJ can be clearly displayed by 3D-CT, and complete or basic contraposition in neutral position and symmetry RFD, HRA and RAC(1-2) in rotary position, are the normal anatomic features of atlanto-axial joints.

Magnetic resonance imaging assessment of craniovertebral ligaments and membranes after whiplash trauma

STUDY DESIGN

Review article.

OBJECTIVES

To review the literature on soft tissue lesions of the upper cervical spine in whiplash trauma with focus on imaging.

SUMMARY OF BACKGROUND DATA

Whiplash injury is associated with chronic impairment in a substantial number of patients. There are different opinions as to the nature and prognosis of this condition, and the role of diagnostic imaging is debated.

METHODS

Review the literature on the anatomic source of the chronic whiplash syndrome. Review the literature on imaging of the upper cervical spine, emphasizing on the author's own research.

RESULTS

MRI shows structural changes in ligaments and membranes after whiplash injury, and such lesions can be assessed with reasonable reliability. Lesions to specific structures can be linked with specific trauma mechanisms. There is a correlation between clinical impairment and morphologic findings.

CONCLUSION

Whiplash trauma can damage soft tissue structures of the upper cervical spine, particularly the alar ligaments. Structural lesions in this area contribute to the understanding of the chronic whiplash syndrome.