Intermediate Cervical Plexus Block in the Management of Refractory Somatosensory Tinnitus Following Whiplash: Prospective Series in 30 Patients

OBJECTIVE

Whiplash-associated disorder comprises of a constellation of persistent symptoms after neck trauma. Tinnitus that develops postwhiplash is termed somatosensory tinnitus. The objective is to assess the role of intermediate cervical plexus block (iCPB) in patients with somatosensory tinnitus secondary to whiplash.

METHODS

Prospective service evaluation in adults with whiplash-associated disorder and concomitant somatosensory tinnitus. Patients underwent specialist otorhinolaryngology review before pain clinic referral. Patients were offered ultrasound-guided iCPB with steroids. Intensity of tinnitus was recorded on a numerical rating scale at baseline, 3 and 6 months posttreatment. Brief Pain Inventory Short Form and Hospital Anxiety Depression Scale questionnaires were also completed.

RESULTS

Over a 36-month period, 32 patients with refractory somatosensory tinnitus following whiplash were offered iCPB(s). Two patients refused because of needle phobia. iCPB(s) was performed in 30 patients as an outpatient procedure. One patient (1/30, 3.3%) was lost to follow-up. Twenty-three patients (23/30, 77%) reported clinically significant reduction in intensity of tinnitus at 3 months postprocedure. Nineteen patients (19/30, 63%) reported ongoing benefit at 6-month follow-up. Six patients failed to report any benefit (6/30, 20%).

CONCLUSION

The cervical plexus could play a significant role in the development of somatosensory tinnitus after whiplash. iCPB may have a role in the management of somatosensory tinnitus in this cohort.

Effect of muscle pre-tension and pre-impact neck posture on the kinematic response of the cervical spine in simulated low-speed rear impacts

Computational human body models (HBMs) can identify potential injury pathways not easily accessible through experimental studies, such as whiplash induced injuries. However, previous computational studies investigating neck response to simulated impact conditions have neglected the effect of pre-impact neck posture and muscle pre-tension on the intervertebral kinematics and tissue-level response. The purpose of the present study was addressing this knowledge gap using a detailed neck model subjected to simulated low-acceleration rear impact conditions, towards improved intervertebral kinematics and soft tissue response for injury assessment. An improved muscle path implementation in the model enabled the modeling of muscle pre-tension using experimental muscle pre-stretch data determined from previous cadaver studies. Cadaveric neck impact tests and human volunteer tests with the corresponding cervical spine posture were simulated using a detailed neck model with the reported boundary conditions and no muscle activation. Computed intervertebral kinematics of the model with pre-tension achieved, for the first time, the S-shape behavior of the neck observed in low severity rear impacts of both cadaver and volunteer studies. The maximum first principal strain in the muscles for the model with pre-tension was 27% higher than that without pre-tension. Although, the pre-impact neck posture was updated to match the average posture reported in the experimental tests, the change in posture was generally small with only small changes in vertebral kinematics and muscle strain. This study provides a method to incorporate muscle pre-tension in HBM and quantifies the importance of pre-tension in calculating tissue-level distractions.

Neck muscle activation in response to eye movement depends on sitting posture and is modified in whiplash associated disorders: Cross-sectional study

BACKGROUND

Activity of specific neck muscles is modulated by eye movement. This activity modulation is exaggerated in people with whiplash associated disorders (WAD), but it is unknown whether it is impacted by sitting posture.

OBJECTIVE

This study investigated; (i) whether activity of cervical muscles differs with spinal posture; (ii) whether the effect of eye gaze direction (horizontal/vertical) on neck muscle activity differs between postures, and (iii) whether these effects differ between individuals with and without WAD.

METHODS

In three seated postures (normal relaxed, head forward, sit tall) electromyography (EMG) was recorded right obliquus capitis inferior (OI), multifidus (MF), splenius capitis (SP) and left sternocleidomastoid (SCM) with fine-wire and surface electrodes in ten healthy controls and nine with WAD. Electro-oculography recorded eye movements.

RESULTS

In controls, EMG was less for extensor muscles in Sit Tall than Head Forward, but higher in SCM. Only SC EMG modulated with eye movement. When WAD participants adopted similar sitting postures several responses were different; compared to Normal Relaxed posture OI EMG was less in Head Forward; MF EMG was less in Sit Tall; and SC was less in Head Forward and Sit Tall. Neck muscles in WAD were generally more sensitive to eye movement, except SC which did not modulate.

CONCLUSIONS

These finding support the hypothesis that neck muscle activity is influenced by spinal posture and eye movement. In WAD, this relationship is distorted and the response to eye movement is increased.

SIGNIFICANCE

These observations have potential implications for clinical management of individuals with WAD.

Citation analysis of the most influential publications on whiplash injury: A STROBE-compliant study

Whiplash injury is a common diagnosis and causes substantial economic burden. Numerous papers have been published to provide new insights into whiplash injury. However, so far there has not been a comprehensive analysis of the most influential publications on whiplash injury. This study aimed to determine the 100 most cited publications on whiplash injury and analyze their characteristics. A keyword search was conducted using the Web of Science database. The top 100 cited publications relevant to whiplash injury were gathered. The main characteristics including title, year of publication, citation, authorship, journal, country, institution, and topic were generated. The number of citations of the top 100 cited publications ranged from 82 to 777. Fifteen countries contributed the top 100 publications. Australia had the largest number of publications (26), followed by the United States (21), and Canada (12). The majority of the publications were from Europe (40) and North America (33). A total of 19 institutions and 17 authors published more than one publication. The University of Queensland (16) and the author Sterling M (7) had the leading publication record. This is the first citation analysis to identify and characterize the highest impact researches on whiplash injury. The present analysis provides the most influential studies on whiplash injury, and reveals the leading journals, counties, institutions, and authors with special contributions in this filed. The list may serve as an archive of historical development of whiplash injury and a basis for further research.

Effectiveness of interventions for middle-aged and ageing population with neck pain: a systematic review and network meta-analysis protocol

INTRODUCTION

Neck pain (NP) is a common musculoskeletal complaint and is increasing in prevalence. Current clinical practice guidelines and systematic reviews recommended conservative, pharmacological and invasive interventions for individuals with NP. However, optimal management specifically for those who are middle-aged or older adults (≥45 years) is not available; and important considering our ageing population.

METHODS AND ANALYSIS

A systematic review with network meta-analysis (NMA) will be conducted following the Cochrane guidelines. Eligibility criteria include randomised controlled/clinical trials evaluating any of acute (<3 months) or chronic (≥3 months) non-specific NP, whiplash associated disorders, cervical radiculopathy and cervicogenic headache. Any interventions and outcome measures detailed within The International Classification of Functioning, Disability and Health domains will be included. Two independent reviewers will search key databases (AMED, CENTRAL, CINAHL, Embase, MEDLINE, PEDro and PsycINFO), grey literature, key journals and reference lists in May 2022. Two reviewers will decide eligibility and assess risk of bias (ROB) of included studies. The kappa statistic will be used to evaluate agreement between the reviewers at each stage. Data will be extracted by one reviewer and checked for accuracy by a second reviewer. Descriptive data and ROB will be summarised and tabulated. Traditional pairwise meta-analysis using random-effect model will be performed for all direct comparisons, and NMA using a frequentist random-effect model then performed based on NP classification where possible. A network of traditional pairwise meta-analysis allows comparisons of multiple interventions from both direct and indirect evidence to provide a hierarchal establishment for enhancing decision making of clinical practitioners.

ETHICS AND DISSEMINATION

Ethic approval is not required as the study is a literature review. The findings will be shared with the national and international researchers, healthcare professionals and the general public through publishing in a peer-reviewed journal and presentations at conferences.

PROSPERO REGISTRATION NUMBER

CRD42021284618.

Reliability of Cervicocephalic Proprioception Assessment: A Systematic Review

OBJECTIVE

The purpose of this systematic review was to determine the reliability and, where possible, the validity of cervicocephalic proprioceptive (CCP) tests in healthy adults and clinical populations.

METHODS

A systematic search, utilizing 7 databases from the earliest possible date to April 14, 2021, identified studies that measured reliability of CCP tests. Studies were screened for eligibility, and included studies were appraised using Quality Appraisal Tool for Studies of Diagnostic Reliability (QAREL) and Quality Assessment and Diagnostic Accuracy Studies-2 Tool (QUADAS-2) tools. Validity outcomes were assessed for included studies.

RESULTS

Of 34 included studies, 29 investigated reliability for sense of position tests, 10 involved sense of movement tests, and 1 used a sense of force test. The head to neutral test was reliable and valid when 6 or more repetitions were performed within the test, discriminating between those with and without neck pain. Head tracking tests were reliable with 6 repetitions, and 1 study found discriminative validity in a whiplash population. Studies that found discriminative validity in sense of position reported mean joint position error generally >4.5° in the neck pain group and <4.5° in the asymptomatic group. No sense of force test was applied to a clinical population. Convergent validity analysis showed that these proprioceptive tests have low correlations with each other.

CONCLUSION

The reliability and validity of CCP tests for sense of position and movement are dependent upon equipment and repetitions. Six repetitions are generally required for good reliability, and joint position error >4.5° is likely to indicate impairment in sense of position.

Cranio-Mandibular Disorders after Whiplash Injury: A Mono-Institutional Clinical Study on 31 Patients

BACKGROUND

Whiplash is a consequence of traumatic injuries, mostly related to road accidents, with variable clinical manifestations, also known as Whiplash Associated Disorders, such as neck, head and temporo-cranio-mandibular pain.

METHODS

The current study aims to evaluate the onset and evolution of temporomandibular joint pain in people with whiplash in a study group treated with the use of Zimmer Collars (adjustable rigid cervical collars for neck immobilization), as compared to a control group. This prospective study included 31 patients followed by the Dental Prosthesis Department of the University of Bari "Aldo Moro": 20 patients with whiplash (age range: 20-39 years) treated with Zimmer collars and 11 patients with whiplash (age range: 20-33 years) who were not. Immediately after the whiplash occurred, a visual analogue scale (VAS) was used to describe the intensity of pain and to complete the chart of the European Academy of Craniomandibular Disorders. Five out of twenty patients, already treated with a Zimmer collar, wore an occlusal splint as well because of persistent pain reported at the 28-day and 60-day follow-up and were supported by pharmacological therapy with analgesics (paracetamol) and muscle relaxants (thiocolchicoside).

RESULTS

During the last follow-up (at six months), three out of five patients displayed a residual VAS score of 3, 4, and 5, respectively, while the remaining two displayed a VAS of 0. In the control group, four out of eleven patients needed to wear an occlusal splint but without muscle relaxants and analgesics pharmacological therapy; these four corresponded to the patients showing a residual painful symptomatology, with VAS reaching value of 2, and also were the oldest patients of the group. Data regarding VAS values and Zimmer collar use, both at the first visit and six months later, were statistically analyzed.

CONCLUSION

Our prospective study highlights how whiplash-associated acute disorders are often self-limiting over a period of few months, thus reducing the possibility of symptom chronicity; the latter seems to be strictly related to lesion severity, pre-existence of a craniomandibular dysfunction and patient age, but appears to be independent from Zimmer collar use, as statistically confirmed.

Normalized vertebral-level specific range of motion corridors for female spines in rear impact

OBJECTIVE

It is well known that the biomechanical responses of female and male spines are different in rear impacts. Female-specific finite element models are being developed as improvements over generic models. Such advancements need female-specific segmental responses for validation. The objectives of the study were to develop vertebral level-specific range of motion corridors from female human cadaver head-neck complexes exposed to rear impact loading.

METHODS

Previously conducted experiments from five human cadaver head-neck complexes were used in this analysis-based study. Briefly, the female head-neck complexes were isolated at the second thoracic vertebral level from the whole body such that the skin and the surrounding tissues of the osteoligamentous complex were intact. The distal end was fixed to the platform of a min-sled testing device. The anterior angulation of T1 was at 25 degrees with respect to the horizontal axis to simulate the normal driver posture. The occipital condyles were directly superior to the T1 body, and the Frankfort plane was horizontal. Rear impact loading were applied at a velocity of 2.6 m/s. The range of motion was defined as the inter-segmental angle at each level of the subaxial spinal column, and it was obtained by tracking the motion of the retroreflective targets that were secured on vertebral bodies and lateral masses of C2 through C7 vertebrae. Data were normalized with respect to the fifth percentile female total body mass, and corridors were developed using the equal stress equal velocity approach and expressed as mean ± 1 standard deviation corridors for each segment.

RESULTS

The segmental motions of the subaxial cervical spinal column were such that the upper regions responded with flexion while the lower regions responded with extension during the initial accelerative loading phase of the impact, resulting in a non-physiological curvature. During the later phase, all segments were in extension. individual corridors are presented as temporal responses in the body of the manuscript. A comparison of the mean temporal responses at each segment are presented to depict the angulation motion differences within the spinal column.

CONCLUSIONS

The present corridors are unique to the female spines. Because female spines have significantly (p < 0.05) different biomechanical responses when compared to male spines, local anatomical differences exist between male and female spines, and field data and clinical studies show female bias to whiplash associated disorders under the rear impact of loading, the present set of corridors serve as a fundamental dataset for the validation of female-specific finite element models. Current computational models can also use these corridors for improved validation to add confidence in their outputs.

Cost-Effectiveness of Chuna Manual Therapy and Usual Care, Compared with Usual Care Only for People with Neck Pain following Traffic Accidents: A Multicenter Randomized Controlled Trial

This is the first cost-effectiveness analysis of Chuna manual therapy (CMT) plus usual Korean traditional medicine for traffic accident victims using a randomized controlled trial. A total of 132 participants were equally allocated to the intervention group receiving 6-11 sessions of CMT plus usual Korean traditional medicine care for three weeks or usual care including acupuncture, cupping, herbal medicine, moxibustion, and traditional physiotherapy at three hospitals. At 12 weeks, from a healthcare perspective, the intervention group had significantly higher costs (mean (SD), $778 (435) vs. $618 (318); difference, $160; 95% CI, $15 to $289; p = 0.005). From a societal perspective, total costs were insignificantly lower in the intervention group (mean (SD), $1077 (1081) vs. $1146 (1485); difference, $-69; 95% CI, $-568 to $377; p = 0.761). The intervention group dominated, with significantly higher QALYs gained at lower overall cost with a 72% chance of being cost-effective. From a societal perspective, the intervention was cost-saving for individuals who had neck pain after car accidents, although it was not cost-effective from the healthcare perspective ($40,038 per QALY gained). Findings support use of CMT as an integrated care treatment for whiplash from a societal perspective. Further studies with larger sample sizes are needed to determine cost-effectiveness in other cultural contexts.

Predicting nonrecovery in adults with incident traffic injuries including post-traumatic headache

IMPORTANCE

The management of traffic injuries is challenging for clinicians. Knowledge about predictors of nonrecovery from traffic injuries may help to improve patient care.

OBJECTIVE

To develop a prediction model for self-reported overall nonrecovery from traffic injuries six months post-collision in adults with incident traffic injuries including post-traumatic headache (PTH).

DESIGN

Inception cohort studies of adults with incident traffic injuries (including PTH) injured in traffic collisions between November 1997 and December 1999 in Saskatchewan, Canada; and between January 2004 and January 2005 in Sweden.

METHODS

Prediction model development and geographical external validation.

SETTING

The Saskatchewan cohort (development) was population-based (N = 4,162). The Swedish cohort (validation) (N = 379) were claimants from two insurance companies covering 20% of cars driven in Sweden in 2004.

PARTICIPANTS

All adults injured in traffic collisions who completed a baseline questionnaire within 30 days of collision. Excluded were those hospitalized > 2 days, lost consciousness > 30 min, or reported headache < 3/10 on the numerical rating scale. Follow-up rates for both cohorts were approximately 80%.

PREDICTORS

Baseline sociodemographic, pre-injury, and injury factors.

OUTCOME

Self-reported nonrecovery from all injuries (not "all better (cured)" on the self-perceived recovery scale) six months after traffic collision.

RESULTS

Both cohorts were predominantly female (69.8% in Saskatchewan, 65.2% in Sweden), with median ages 35.9 years (Saskatchewan), and 38.0 years (Sweden). Predictors were age, low back pain, symptoms in arms or hands, hearing problems, sleeping problems, pre-existing headache, and lower recovery expectations. With a positive score (i.e., ≥0.85 probability), the model can rule in the presence of self-reported nonrecovery from all injuries at six months (development: specificity = 91.3%, 95% CI 89.2%-93.0%; sensitivity = 27.8%, 95% CI 26.0%-29.7%; positive likelihood ratio (LR + ) = 3.2, 95% CI 2.5-4.0; negative likelihood ratio (LR-) = 0.79, 95% CI 0.76-0.82; validation: specificity = 72.6%, 95% CI 61.4%-81.5%; sensitivity = 60.5%, 95% CI 53.9%-66.7%); LR+ = 2.2, 95% CI 1.5-3.3; LR- = 0.5, 95% CI 0.4-0.7).

CONCLUSIONS AND RELEVANCE

In adults with incident traffic injuries including PTH, predictors other than those related to baseline head and neck pain drive overall nonrecovery. Developing and testing interventions targeted at the modifiable predictors may help to improve outcomes for adults after traffic collision.

One-Year Follow-Up after Multimodal Rehabilitation for Patients with Whiplash-Associated Disorders

Long-term symptoms after whiplash injury often comprise neck pain, headache, anxiety, depression, functional impairment and low quality of life. In an observational cohort study, we examined physical and mental health effects in patients with subacute to chronic whiplash-associated disorders (WAD) after participation in a multimodal rehabilitation (MMR) program. MMR is a team-based multi-professional method based on a bio-psycho-social model with a cognitive focus to reach an individualized and common goal for the team and patient together. Standardized self-report questionnaires were filled in three times: before MMR, after MMR, and one year after MMR. A total of 322 participants completed the program, 161 of whom responded in full and were further analyzed. At one-year follow-up after MMR, a significant improvement was seen in the evaluation of the primary outcomes (physical and mental health) and secondary outcomes (anxiety, depression, pain intensity and interference with life). Women improved on all outcomes while men did not improve on the psychological measures (mental health, depression and anxiety). This study indicates that a MMR program could be beneficial for patients with subacute to chronic WAD, at least for women, since the outcomes at one-year follow-up were positive.

Impact of interventions on work-related outcomes for individuals with musculoskeletal injuries after road traffic crash: a systematic review protocol

BACKGROUND

Musculoskeletal injuries are the most common non-fatal injury from road traffic crashes. Even when the injuries are mild, they can cause pain which can affect return to work rates and work ability post-crash. Workplace output losses are the biggest cost from traffic crash-related injuries. There is a need to identify effective interventions that can improve work-related outcomes (e.g. time to return to work, sick leave, and work ability) in this group and a need to understand the intervention components, external factors, and participant characteristics that may be associated with improvement.

METHODS

A systematic review will be conducted using seven databases and search terms related to road traffic crash, musculoskeletal injury, work-related outcomes, and study design. Intervention studies will be eligible if they report on at least one work-related outcome, include adults with a traffic crash-related musculoskeletal injury (e.g. fracture or whiplash), include a comparison group, and are written in English. Interventions can be medical, therapeutic, work-based, multicomponent, or other. Two researchers will independently screen titles and abstracts, review full texts for inclusion in the review, and perform the data extraction. The main outcomes of the review will be time until return to work and duration of sick leave. The results will be narratively described, with meta-analyses conducted where possible.

DISCUSSION

This review will explore the effectiveness of interventions in individuals with traffic crash-related musculoskeletal injury on work-related outcomes and will act as a useful source for researchers, policy makers, and stakeholders when developing and implementing interventions in this group.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018103746.

Performance properties of health-related measurement instruments in whiplash: systematic review protocol

BACKGROUND

Whiplash is a common traumatic cervical injury which is most often a consequence of rear-end motor vehicle accidents. It has been estimated that up to 50% of the whiplash patients suffer from chronic symptoms, resulting in extensive individual and societal burden. Several measurement instruments are used for initial assessment of whiplash and evaluation of response to treatment. However, a comprehensive assessment of the performance of these measures is lacking. Furthermore, there is no consensus on the most relevant outcome domains and their corresponding measurement instruments of choice. This systematic review aims to identify, describe, and critically appraise the performance properties of health-related measurement instruments in whiplash population.

METHODS

The following literature databases will be searched from their date of establishment: PubMed, Embase®, MEDLINE, CINAHL Complete, PsycINFO, and HAPI. All original articles evaluating the reliability, validity, responsiveness, and feasibility of health-related measurement instruments in whiplash will be included, without additional restriction on their intended use, source of data, and structure. Risk of bias will be assessed using the COSMIN Risk of Bias checklist. Findings of the studies will be judged against the criteria for good measurement properties, and results from all studies will be qualitatively summarized to generate an overall quality of findings. Overall quality of evidence will be determined using a modified GRADE approach, which will be used in conjunction with the overall quality of results for generation of recommendations. Two reviewers will perform all steps of the review independently. Discrepancies will be discussed between the reviewers, and in case of remaining disagreement, the senior reviewer will make the final decision.

DISCUSSION

This systematic review will summarize the body of literature on health-related measurement instruments in whiplash, aiming to facilitate the selection of high-quality measurement instrument for researchers and physicians. Findings of this study will guide the ongoing efforts for development of a core outcome set.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO reference number CRD42018070901.

Relationship Between Psychosocial Factors and Pain in the Jaw and Neck Regions Shortly After Whiplash Trauma

AIMS

To assess jaw pain shortly after whiplash trauma in relation to neck pain, physical symptoms, depression, and jaw pain-related disability.

METHODS

A total of 181 cases (106 women and 75 men, mean ages 33.7 and 36.8 years, respectively) were examined within 1 month after a whiplash trauma and compared to 117 controls (68 women and 49 men, 34.2 and 30.9 years, respectively). Participants rated current jaw and neck pain intensity on a numeric rating scale and rated nonspecific physical symptoms and depression symptoms on subscales of the Symptom Checklist-90-Revised. The nonspecific physical symptoms were further analyzed with and without pain items. Disability related to jaw pain and neck pain was also assessed. Differences between groups were calculated using Mann-Whitney U test, and correlations were measured using Spearman correlation.

RESULTS

Compared to controls, cases reported higher current jaw and neck pain intensity (P < .0001), together with higher scores for physical nonpain and pain symptoms, depression, and jaw pain-related disability (P < .0001 for all). For cases, there were moderate correlations between nonspecific physical symptoms and jaw pain and neck pain, as well as between jaw pain-related disability and jaw pain and neck pain (r = 0.43 to 0.77, P < .0001 for all). Low correlations were observed between depression and jaw pain and neck pain (r = 0.34 to 0.39, both P < .0001).

CONCLUSION

Shortly after a whiplash trauma, pain in the jaw and neck regions is associated with the severity of psychosocial factors. Thus, psychosocial factors may play a role in the development of pain in the jaw region after whiplash trauma.

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.

Driving position field study, differences with the whiplash protocol and biomechanics experimental responses

Rear-impact collisions at low speed are a leading cause of economic costs among motor vehicle accidents. Recently, EuroNCAP has incorporated in its protocol the whiplash test, to reproduce a low-speed rear impact. This paper presents a field driving study to assess the potential differences between the EuroNCAP dummy tests and actual drivers in the field, focusing on occupant position and biomechanics experimental results. A total of 182 drivers were randomly selected in two geographical areas in Spain. The driving position of each driver was recorded with a focus on the most relevant measurements for rear impact. Statistical analysis was performed to obtain means, standard deviations and density functions to compare observational seating position with that of the EuroNCAP testing protocol. The observational data showed a similar seatback angle to that used in the EuroNCAP protocol (24° in front of 25° for the protocol), a greater distance between the head vertex and the top of the head restraint (53mm compared to 39.5mm), and less distance between the occipital bone of the head and the headrest (67.9 compared to 89.3mm). Based on these data, 4 dummy tests were conducted using the dummy BioRID IIg. The baseline test was designed to reproduce the dummy position according to EuroNCAP 3.0 whiplash protocol. Three different additional tests were defined to reproduce the actual observed driving position as well as to assess a "worst case" scenario in terms of reduced seatback angle. These variations in initial driver position, comparing the EuroNCAP protocol to the observational study results, were not observed to cause significant differences in the biomechanical values measured in the BioRID IIg, The T1 acceleration was reduced less than 8%, the NIC was increased about 8%, and the NKm presented a reduction of 20%. Reducing the seat angle was observed to be more harmful in terms of NIC.

Cervical range of motion and proprioception in rugby players versus non-rugby players

In this study, we examined the effects of number of years of playing rugby on neck function. Active cervical spine range of motion and proprioception were assessed in 14 non-rugby-playing but trained sportsmen (mean age 28 years, s = 7) and 46 rugby players (26 rugby forwards: mean age 26 years, s = 5; mean years played 14 years; 20 backs: mean age 24 years, s = 5; mean years played 14 years). Active cervical range of motion in flexion, extension, left and right lateral flexion, plus left and right rotation were measured using a cervical range of motion device. The ability to reposition the head in a central position with eyes closed was taken as a measure of proprioception. Results show that rugby forwards generally had the least active cervical range of motion, particularly neck extension (forwards, 43 degrees ; backs, 55 degrees ; controls, 58 degrees ), with the decrement correlating with the number of years played. In addition, repositioning was significantly worse in rugby players after neck extension than non-rugby players (6 degrees vs. 3 degrees ). The active cervical range of motion of rugby forwards is similar to that of whiplash patients, suggesting that participation in rugby can have an effect on neck range of motion that is equivalent to chronic disability. Reduced active cervical range of motion could also increase the likelihood of injury and exacerbate age-related neck problems.

Whiplash: fact or fiction?

Cervical sprain/strain or whiplash injuries are a common cause of acute and chronic musculoskeletal impairments and are ubiquitous after rear-end automobile collisions. The diagnosis is largely subjective and the ideal treatment controversial. Unfortunately, the majority of compensated litigation claims are associated with whiplash-type injuries secondary to motor vehicle accidents. Fortunately, many recent advances have led to better understanding of the collision and injury biomechanics and to development of a prognostic classification system, objective diagnostic tests, an array of treatment modalities, and, most important, safer automobiles. These advances will undoubtedly lead to decreased incidence, a more accurate diagnosis, and a tailored management regimen resulting in improved outcomes and ultimately fewer legal proceedings.

Using a finite element model to evaluate human injuries application to the HUMOS model in whiplash situation

STUDY DESIGN

In the field of numerical simulation, the finite element method provides a virtual tool to study human tolerance and postulate on potential trauma under crash situations, particularly in case of whiplash trauma.

OBJECTIVES

To show how medical and biomechanical interpretations of numerical simulation can be used to postulate on human injuries during crash situations. This methodology was applied to whiplash trauma analysis. A detailed analysis of kinematics of joints, stress level in hard tissues, and strain level in soft tissues was used to postulate on chronology and patterns of injury. Data were compared with published biomechanical and clinical studies of whiplash.

SUMMARY OF BACKGROUND DATA

Although many in vitro and in vivo studies have been conducted to investigate whiplash cervical injury, and despite the number of finite element models developed to simulate the biomechanical behavior of the cervical spine, to date, there are only limited finite element models reported in the literature on the biomechanical response of the whole cervical spine in these respects.

METHODS

A complete finite element model of the human body (HUMOS) build in a sitting position in a car environment was created to investigate injury mechanisms and to provide data for automotive safety improvements. It includes approximately 50,000 elements, including descriptions of all bones, ligaments, tendons, skin, muscles, and internal organs. A 15-g whiplash injury was simulated with the HUMOS model. The model predicted cervical motion segment kinematics, deformations of disks and ligaments, and stresses in bone. Model output was then compared with experimental and clinical whiplash literature.

RESULTS

In term of kinematics during the chronology of whiplash, two injury phases were identified: the first was hyperextension of the lower cervical spine (C6-C7 and C5-C6) and mild flexion of the upper cervical spine(C0-C4). The amount of upper cervical flexion was 15 degrees from C0 to C4. The second phase was hyperextension of the entire cervical spine. Potential patterns of ligamentous injuries were observed; the anterior longitudinal ligament experienced the most strain (30%) at the lower cervical spine at the time of lower cervical extension and the interspinous ligament experienced the most strain (60%) at the time of upper cervical flexion. Von Mises stresses in bone do not exceed 15 Mpa, which is largely under injury levels reported in the literature. CONCLUSIONS.: This study reports a methodology to describe and postulate on human injuries based on finite element model analysis. The output of the HUMOS model in the context of whiplash shows a strong correlation with clinical and experimental reported data. HUMOS shows promise for the modeling of other types of trauma as well.

Validity and internal consistency of a whiplash-specific disability measure

STUDY DESIGN

Cross-sectional study of patients with whiplash-associated disorders investigating the internal consistency, factor structure, response rates, and presence of floor and ceiling effects of the Whiplash Disability Questionnaire (WDQ).

OBJECTIVES

The aim of this study was to confirm the appropriateness of the proposed WDQ items.

SUMMARY OF BACKGROUND DATA

Whiplash injuries are a common cause of pain and disability after motor vehicle accidents. Neck disability questionnaires are often used in whiplash studies to assess neck pain but lack content validity for patients with whiplash-associated disorders. The newly developed WDQ measures functional limitations associated with whiplash injury and was designed after interviews with 83 patients with whiplash in a previous study.

METHODS

Researchers sought expert opinion on items of the WDQ, and items were then tested on a clinical whiplash population. Data were inspected to determine floor and ceiling effects, response rates, factor structure, and internal consistency. Packages of questionnaires were distributed to 55 clinicians, whose patients with whiplash completed and returned 101 questionnaires to researchers.

RESULTS

No substantial floor or ceiling effects were identified on inspection of data. The overall floor effect was 12%, and the overall ceiling effect was 4%. Principal component analysis identified one broad factor that accounted for 65% of the variance in responses. Internal consistency was high; Cronbach's alpha = 0.96.

CONCLUSIONS

Results of the study supported the retention of the 13 proposed items in a whiplash-specific disability questionnaire. Dependent on the results of further psychometric testing, the WDQ is likely to be an appropriate outcome measure for patients with whiplash.

From railway spine to whiplash--the recycling of nervous irritation

The search for a specific structural basis for chronic whiplash and other chronic pain and fatigue syndromes has been in progress for decades, and yet currently there remains no "structural" solution to these enigmata. In light of the failure of research to identify the chronic "damage" or pathology as lying in a muscular, bony, or "connective tissue" sites for many chronic pain syndromes like whiplash, fibromyalgia, et cetera, more recent attention has been paid to nervous system structures. Nerve irritation has been implicated as the basis for the pain and other symptoms that are common to many chronic disability syndromes. We postulate here, however, that the concept of nervous irritation has been prostituted for centuries whenever more concrete structural explanations for chronic pain and other controversial illness have been untenable. We suggest that, after each cycle of nervous irritation as a disease, and subsequent dismissal of the notion, the doctrine of irritation as a disease was too good to go away. First, with the hypersthenic and asthenic diseases of the nineteenth century, then railway spine, whiplash, thoracic outlet syndrome, and now brachial plexus irritation, we detect the same pattern: patients with symptoms, but no objective evidence of nerve disease. Nervous irritation has repeatedly served this purpose for the last 200 years. It is our intent that bringing an understanding of this trend will encourage current clinicians and researchers to appreciate the need to abandon this form of speculation without historical insight when dealing with today's controversial syndromes.

[Selection of subjects: a problem of clinical trials in traumatology. Selection effects and the problem of representation as exemplified by a prospective randomized trial on whiplash injuries]

INTRODUCTION

The internal and external validity of studies is endangered by many factors, such as selection of subjects for inclusion. Selection bias itself is a major problem, but remains unmentioned and probably unexamined in the majority of published clinical trials in traumatology.

AIM OF THE STUDY

The aim of this investigation was to detect effects of subject selection which occurred during our own prospective intervention study. The clinical trial compared subjects with whiplash injury who were either treated by early mobilization or immobilization (soft collar).

MATERIAL AND METHODS

Source population, eligible subjects, study participants and final study participants were compared for differences on various items like age, gender and further sociodemographic as well as crash related factors and clinical findings.

RESULTS

Between 21.08.1997 and 30.04.1999 a total of 732 patients was examined and treated after whiplash in our trauma department. The options for inclusion were met by 453 patients. While 346 escaped from the study, 107 agreed to participate. Of these another 39 patients dropped out of the study. Selection effects were detected on two different levels, leading to distinct statistical procedures from those proposed in the study protocol.

CONCLUSIONS

Uncontrolled selection effects could undermine the interpretability of the results of clinical trials. Awareness of selection effects is mandatory regarding the applicability of these results to subjects, other than those in the group of the final study participants.

Whiplash around the world

The term "whiplash" was first used in 1928 by the American orthopedist Crowe, although the earliest use that I can find published was in 1945 by the American orthopedist Davis. Although widely used by the medical profession and public, many physicians find the term objectionable. However, when used appropriately to refer only to the mechanism of injury in a motor vehicle accident, the term can be worthwhile. In any case, "whiplash" is well-entrenched in usage and is here to stay. But what term is used in other languages? Is there a term similar to "whiplash?" To determine terms for whiplash injuries in other languages, members of the American Academy of Neurology living in non-English-speaking countries were contacted by mail. Terms used in 11 other languages are listed. Some comments about whiplash injuries by respondents are excerpted. Further cross-cultural studies may be helpful in studying the influence of physician and popular attitudes, as well as litigation on persistent neck complaints and headaches after motor vehicle accidents.

Cervical strain and mandibular whiplash: effects upon the craniomandibular apparatus

One of the most common injuries that can lead to a multitude of problems is cervical strain and mandibular whiplash resulting from a motor vehicle accident. Many individuals do not fully recover from such injuries, develop additional areas of pain and dysfunction weeks or months after the accident, and/or sustain major trauma that may require surgical intervention. Other than fractures or dislocations of cervical vertebrae, which are usually easily discerned from radiological analysis, two prime factors frequently lead to a prolongation of pain, a long rehabilitation course, and the development of problems at adjacent structures such as the craniomandibular region. These two factors are: 1) the lack of early comprehensive evaluation and referral for definitive therapeutic intervention, and 2) a minimal awareness of the relationship of upper quarter structures to one another. The purpose of this paper is to foster within the reader an appreciation of the interrelationship of the cervical and craniomandibular architectures as well as the significance of proper evaluation and treatment of cervical strain and mandibular whiplash injuries.

[The mechanics of whiplash injury of the cervical spine (author's transl)]

Despite many attempts it has so far not been possible to establish a uniform application of the term "whiplash injury" either for diagnostics, therapy, or medical reports. To obtain a clear, functionally based definition, the most frequently used formulations are compared, taking into account anatomic and mechanical aspects in addition. Whiplash injury is separated from hyperextension injury ("snap" trauma of the cervical spine), even though overlaps in the lesion picture are possible. In the definition suggested, invariable linkage to rear-end collision is dispensed with. Instead, it is emphasized that this accident mechanism is frequent, but can also be substituted. In contrast to other definitions, special emphasis is laid on the biphasic course since a substantial traumatization is to be assumed to occur from the secondary movement. This second movement does not by any means proceed with low energy, but its determined by the mass contraction of the muscle group subject to primary abrupt overextension with their synergists. On the basis of the analysis of the mechanical course and the investigation of a actual accidents, the monosegmental cervical spine injury cannot, therefore, be seen as the characteristic type of damage due to a whiplash injury. Instead of this, the frequent occurrence of multiple injuries is pointed out.