Magnetic Resonance Imaging-Based Prediction of the Relationship between Whiplash Injury and Temporomandibular Disorders

Abstract

Purpose: Whiplash injury can cause internal derangement of the temporomandibular joint (TMJ) and lead to temporomandibular disorders (TMDs). Our aim was to evaluate whether the initial clinical findings in TMD patients with whiplash injury are correlated with their magnetic resonance imaging (MRI) characteristics.

Materials and methods: This case-control study involved 219 patients (135 women, 84 men; mean age: 37.84 years) who visited our orofacial pain clinic with TMD; TMD was diagnosed using the diagnostic criteria for TMD Axis I. Patients were categorized into three groups based on the presence and type of macrotrauma: in the "wTMD" group, patients had suffered whiplash injury; patients in the "pTMD" group had post-traumatic TMD; the "iTMD" group comprised patients who had presented with TMD symptoms and had sustained no macrotrauma. We investigated the presence of disk displacement, effusion, disk deformity, and condylar degeneration, and changes in the lateral pterygoid muscle (LPM). To evaluate the severity of TMD pain and objectively analyze symptoms, we used a visual analog scale (VAS), palpation index (PI), neck PI, dysfunction index, and craniomandibular index (CMI).

Results: The VAS scores, and the severity indexes of the TMD including PI, neck PI, and CMI were highest in the wTMD patients. Atrophy of the LPM was most commonly seen in the wTMD group, as was disk deformity. In wTMD patients only, VAS score was significantly correlated with stress; it was correlated with headache in wTMD and iTMD patients. The clinical symptoms of TMD were not correlated with MRI findings in the wTMD group. However, alterations in the LPM were strongly correlated with disk displacement.

Conclusion: If clinicians recognize alterations in the LPM and disk displacement in the TMJ, they will better understand the clinical symptoms and pathophysiology of TMD with whiplash injury. Whiplash injury may lead to TMD via different mechanisms from other macrotraumas.

Keywords: macrotrauma; magnetic resonance imaging; neck pain; temporomandibular disorder; whiplash injury.

Figure 1

Possible mechanism of temporomandibular disorder evoked from whiplash injury. On extension, the temporomandibular joint (TMJ) elongated and abrupt mouth opening can occur. On flexion, the TMJ is compressed and lateral pterygoid muscle’s spasm can occur.

Figure 2

Magnetic resonance imaging (MRI) features of the abnormal temporomandibular joint disk and lateral pterygoid muscle (LPM). (A,B) Anterior disk displacement with reduction. Sagittal oblique gradient-echo T1-weighted image with closed-mouth position shows an anterior displaced disk (A) and MRI with open-mouth position shows that the disk has returned to its normal position between the condyle and the temporal bone (B). (C,D) Anterior disk displacement without reduction. MR image shows a disk displaced from its normal position in closed-mouth position (C) and the disk remains displaced from its normal location in the open-mouth view (D). (E) Sagittal T2-weighted image (T2WI) shows a round shape displaced disk and arthritis of mandibular condyle. (F) T2WI shows clearly delineated articular fluid collection with hyperintensity. Sagittal proton density image shows fatty and atrophic change of right LPM (G) when compared with contralateral normal LPM (H).