Motor vehicle accidents and TMDS: assessing the relationship

Whiplash-associated temporomandibular disorders: a review article

Data from the literature on temporomandibular disorder (TMD) amplification or exacerbation in whiplash injuries is quite discordant. Substantial controversy exists regarding the incidence, prevalence, proposed mechanism of injury, clinical characteristics, and prognosis of TMDs due to whiplash.This article describes this controversy and presents findings from contemporary literature.

A risk stratification tool for prehospital triage of patients exposed to a whiplash trauma

OBJECTIVE

Our aim was to develop a risk stratification model to predict the presence of a potentially more sinister injury in patients exposed to a whiplash trauma.

METHODS

The study base comprised of 3,115 residents who first sought healthcare contact within one week after being exposed to a whiplash trauma between 1999-2008, from within a defined geographical area, Skaraborg County in south-western Sweden. Information about gender, age, time elapsed prior to seeking care, type of health care contact, and hospitalisation was retrieved. Seventeen potential risk factors were identified and evaluated using multivariable logistic regression.

RESULTS

Of 3,115 patients, 215 (6.9%) required hospital admission so theoretically 93% could have been initially assessed by primary health care. However, only 46% had their first contact in primary health care. All patients had symptoms resulting in a diagnosis of whiplash injury. Four risk factors were found to be associated with hospital admission: commotio cerebri (OR 31, 19-51), fracture / luxation (OR 11, 5.1-22), serious injury (OR 41, 8.0-210), and the patient sought care during the same day as the trauma (OR 5.9, 3.7-9.5). These four risk factors explained 27% of the variation for hospital admission and the area under curve (AUC) was 0.77 (0.74-0.80). Ninety-six percent of patients (2,985) had only a whiplash injury with no other injury. These could be split into those attending health care the same day as the trauma, 1,737 (56%) with a 7.1% risk for hospital admission, and those attending health care later, 1,248 (40%) with a 1.3% risk for hospital admission.

CONCLUSION

Patients with no signs of commotio cerebri, no fracture/luxation injury, no serious injury, comprising 96% of all patients exposed to a whiplash trauma can initially be referred to primary health care for initial assessment. However, those contacting the health care the same day as the trauma should be referred to a hospital for evaluation if they can't get an appointment with a general practitioner the same day.

Gender differences in care-seeking behavior and healthcare consumption immediately after whiplash trauma

OBJECTIVE

The aim was to study gender differences in care-seeking behavior and treatment provided immediately after whiplash trauma.

METHODS

Participants were residents from a defined geographical area, Skaraborg County in the southwestern part of Sweden. A cohort of 3,368 persons exposed to whiplash trauma and attending a healthcare facility immediately after the trauma between 1999 and 2008 were identified in a database. Information about gender, age, time elapsed prior to seeking care, type of healthcare contact, initial treatment provided and eventual hospitalization time was retrieved.

RESULTS

Women sought care later than men (p = 0.00074). Women consulted primary healthcare first more often than men, who more often first sought hospital care (p = 0.0060). There were no gender differences regarding the type of treatment after trauma. Women had longer hospital admission than men (p = 0.022), indicating their injuries were at least similar to or worse than men's.

CONCLUSION

Women sought healthcare later than men after whiplash trauma. Although not directly investigated in this study, it raises the question if this may reduce their probability of getting financial compensation compared to men.

The relationship of whiplash injury and temporomandibular disorders: a narrative literature review

OBJECTIVE

The purpose of this article is to offer a narrative review and discuss the possible relationship between temporomandibular disorders (TMDs) and whiplash injuries.

METHODS

Databases from 1966 to present were searched including PubMed; Manual, Alternative, and Natural Therapy Index System; and Cumulative Index for Nursing and Allied Health Literature. Search terms used included whiplash injury, temporomandibular disorders and craniomandibular disorders. Inclusion criteria consisted of studies on orofacial pain of a musculoskeletal origin addressing the following topics: posttraumatic temporomandibular disorder (pTMD) incidence and prevalence, mechanism of injury, clinical findings and characteristics, prognosis (including psychologic factors). Excluded were studies of orofacial pain from nontraumatic origin, as well as nonmusculoskeletal causes including neurologic, vascular, neoplastic, or infectious disease.

RESULTS

Thirty-two studies describing the effects of whiplash on TMD were reviewed based on inclusion/exclusion criteria. The best evidence from prospective studies indicates a low to moderate incidence and prevalence. Only 3 studies addressed mechanism of injury theories. Most studies focusing on clinical findings and characteristics suggest significant differences when comparing pTMD to idiopathic/nontraumatic patients. Regarding prognosis, most studies suggest a significant difference when comparing pTMD to idiopathic/nontraumatic TMD patients, with pTMD having a poorer prognosis.

CONCLUSIONS

There is conflicting evidence regarding the effects of whiplash on the development of TMD. Furthermore, because of lack of homogeneity in the study populations and lack of standardization of data collection procedures and outcomes measured, this review cannot conclusively resolve the controversies that exist concerning this relationship. This review of the literature is provided to clarify the issues and to provide useful clinical information for health care providers managing TMD such as doctors of chiropractic, physical therapists, dentists, and medical doctors.

Dynamic 3D FE modelling of the human temporomandibular joint during whiplash

Rear-end impacts account for more than one-third of vehicle accidents, and nearly 40% of these accidents produce whiplash injuries. Whiplash injury to the neck has often been considered a significant risk factor for the development of temporomandibular disorders (TMD). The objective of this study was to simulate the dynamic response of the temporomandibular joint during two types of impacts: a rear end and a frontal impact. To understand the dynamic forces acting on the joint, we extended a previous human temporomandibular joint model and analyzed the stress distributions in the soft elements of the joint. In the rear-end impact, it could be appreciated that the inertia of the mandible caused it to move posteriorly slower than the head, and this resulted in downward and forward displacements of the disc-condyle complex relative to the cranial base. Consequently, a rapid and big mouth opening occurs. In contrast, during the frontal impact, the mouth hardly opened, because the superior maxilla pushed the mandible to move together. There was not differential movement between bony components of the joint and therefore the soft tissues of the joint were not subjected to high loads. From these results, and despite the limitations of the simulations performed, we could conclude that neither a rear-end impact at low-velocity nor a frontal impact would produce damage to the soft tissues of the joint.

Radiographic and clinical features of temporomandibular dysfunction in patients following indirect trauma: A retrospective study

OBJECTIVES

Patients developing temporomandibular dysfunction (TMD) following a motor vehicle accident (MVA) have been reported to respond poorly to standard TMD treatment compared with TMD patients who have not sustained an MVA. The purpose of this study was to determine clinical and radiographic differences between post-MVA and nontrauma TMD patients and to determine whether radiographic findings in post-MVA patients undergoing litigation show more severe anatomical changes than post-MVA patients not undergoing litigation.

STUDY DESIGN

One hundred thirty-six files with magnetic resonance imaging (MRI) and/or bone scan studies of TMD patients were randomly drawn (54 post-MVA and 82 nontrauma TMD).

RESULTS

Patients with post-MVA TMD demonstrated significantly more orofacial pain complaints but significantly less disk displacements on MRI (47.5% post-MVA vs. 69.2% control; P = .03). Litigating post-MVA patients had significantly more nonreducing disks than the nonlitigating group (37.7% litigating vs. 7.7% nonlitigating; P = .05).

CONCLUSION

Based on these findings, it is suggested that treatment limited to the temporomandibular joints (TMJs) in post-traumatic TMD patients may fail without consideration that pain may originate in structures other than the TMJs. Within the post-MVA group, the more severe anatomical changes were found in the litigating patients, suggesting that some of their symptoms are associated with anatomical changes.

Mandibular kinematics associated with simulated low-velocity rear-end impacts

Rear-end-impact motor vehicle accidents may result in cervical and temporomandibular-related pain complaints. Head kimematics in simulated low-impact rear-end impacts have been investigated but mandibular kinematics have not been described. Thirty healthy adult subjects underwent three impacts (4.5 m s(-2) expected, 10.0 m s(-2) unexpected, and 10.0 m s(-2) expected). Onset time and peak magnitude of angular head acceleration, angular mandibular acceleration and angular mandibular displacement were measured. Significant mandibular opening acceleration was not identified with rearward head rotation. The peak magnitude of mandibular closing angular acceleration approximately doubled with increased impact magnitude. No differences in peak angular mandibular acceleration regarding expectation were identified. Gender differences were detected in the fast unexpected impact. The peak time for the angular mandibular acceleration (mandibular closure) was approximately 84-120 ms later than peak rearward angular head acceleration for all impacts. Onset and peak times for angular mandibular acceleration (mandibular closure) were similar to the onset and peak times for forward head acceleration. There was also a positive correlation between the magnitude of the forward angular acceleration of the head and angular acceleration of the mandible for the slow (0.65, P = 0.015) and fast expected (0.844, P = 0.001) impacts. The average angular mandibular angular displacement (mandibular closure) was approximately 6 degrees . The hyperextension hypothesis regarding mechanism of temporomandibular joint injury in low-impact rear-end collisions cannot be supported.

Medical legal considerations in temporomandibular disorders

Dentists commonly see patients with temporomandibular disorders who are involved in litigation, and dentists are occasionally accused of temporomandibular disorder-related negligence. Rapidly changing scientific knowledge must be reflected in dental practice and in the courtroom, where dentists act as experts. In this article, concepts pertaining to assessments of patients with temporomandibular disorders for impairment and disability and concepts pertaining to legal causation are discussed, especially in relation to motor vehicle accidents. Recommendations for avoiding malpractice suits are presented.

Concurrent cervical and craniofacial pain. A review of empiric and basic science evidence

Because many patients present themselves for treatment with both craniofacial and craniocervical pain, 2 questions arise: (1) What are the sensory and motor consequences of dysfunction in either of these areas on the other? (2) Do craniofacial and craniocervical pain have a similar cause? These questions formed the impetus for this review article. The phenomenon of concurrent pain in craniofacial and cervical structures is considered, and clinical reports and opinions are presented regarding theories of cervical-to-craniofacial and craniofacial-to-cervical pain referral. Because pain referral between these 2 areas requires anatomic and functional connectivity between trigeminally and cervically innervated structures, basic neurophysiologic and neuroanatomic literature is reviewed. The published data clearly demonstrate neurophysiologic and structural convergence of cervical sensory and muscle afferent inputs onto trigeminal subnucleus caudalis nociceptive and non-nociceptive neurons. Moreover, changes in metabolic activity and blood flow in the brainstem and cervical dorsal horn of the spinal cord in both monkeys and cats have been demonstrated after electric stimulation of the V1-innervated superior sagittal sinus. In conclusion, the animal experimental data support the findings of human empiric and experimental studies, which suggest that strong connectivity exists between trigeminal and cervical motor and sensory responses.

Effect of impact and injury characteristics on post-motor vehicle accident temporomandibular disorders

OBJECTIVES

The objective of this study was to assess the potential effects of motor vehicle accident impact and injury characteristics on post-motor vehicle accident temporomandibular disorders in terms of presenting signs and symptoms, diagnoses, treatment regimens, and outcomes.

STUDY DESIGN

A retrospective chart review of 50 patients with post-motor vehicle accident temporomandibular disorders from a private oral medicine practice was undertaken. Various demographic data and data related to temporomandibular disorders and motor vehicle accident impact and injury characteristics were collected. Chi-square and Fisher exact tests and multiple regression analyses were performed.

RESULTS

Patients involved in front-end collisions or motor vehicle accidents resulting in severe vehicle damage reported more direct orofacial injury. However, those in rear-end collisions or accidents resulting in minimal vehicle damage required more treatment. Direct head or orofacial injury was therefore not a prognostic indicator. From multiple regression analyses, indicators of a poorer prognosis were minimal vehicle damage, lack of headrest use, driver position, and settlement of insurance claim.

CONCLUSIONS

In this patients group several prognostic indicators for patients with post-motor vehicle accident temporomandibular disorders were identified; these indicators may influence the management approach for this patient population.