MRI-Based Assessment of Masticatory Muscle Changes in TMD Patients After Whiplash Injury

Abstract

Objective To investigate the change in volume and signal in the masticatory muscles and temporomandibular joint (TMJ) of patients with temporomandibular disorder (TMD) after whiplash injury based on magnetic resonance imaging (MRI) and to correlate them with other clinical parameters. Methods Ninety patients (64 women, 26 men; mean age: 39.36 ± 15.40 years), including 45 patients with symptoms of TMD after whiplash injury (wTMD), and 45 age- and sex-matched controls with TMD due to idiopathic causes (iTMD) were included. TMD was diagnosed using the study diagnostic criteria for TMD Axis I, and MRI findings of the TMJ and masticatory muscles were investigated. To evaluate the severity of TMD pain and muscle tenderness, we used a visual analog scale (VAS), palpation index (PI), and neck PI. Results TMD indexes, including VAS, PI, and neck PI were significantly higher in the wTMD group. In the wTMD group, muscle tenderness was highest in the masseter muscle (71.1%), and muscle tenderness in the temporalis (60.0%), lateral pterygoid muscle (LPM) (22.2%), and medial pterygoid muscle (15.6%) was significantly more frequent than that in the iTMD group (all p < 0.05). The most noticeable structural changes in the masticatory muscles occurred in the LPM with whiplash injury. Volume (57.8% vs. 17.8%) and signal changes (42.2% vs. 15.6%) of LPM were significantly more frequent in the wTMD group than in the iTMD group. The presence of signal changes in the LPM was positively correlated with the increased VAS scores only in the wTMD group (r = 0.346, p = 0.020). The prevalence of anterior disc displacement without reduction (ADDWoR) (53.3% vs. 28.9%) and disc deformity (57.8% vs. 40.0%) were significantly higher in the wTMD group (p < 0.05). The presence of headache, sleep problems, and psychological distress was significantly higher in the wTMD group than in the iTMD group. Conclusion Abnormal MRI findings and their correlations with clinical characteristics of the wTMD group were different from those of the iTMD group. The underlying neuropathophysiology may differ depending on the cause of TMD, raising the need for a treatment strategy accordingly.

Magnetic resonance imaging evaluation of masticatory muscle changes in patients with primary trigeminal neuralgia before microvascular decompression

“…At the same time, ve patients exhibited hypertrophy of the contralateral masticatory muscles, which may be compensatory hypertrophy [12]. The masticatory muscles play the role of moving the mandible, while the lateral pterygoid muscles are the only muscles that depress the mandible and cannot trigger an attack of pain [4,13]. Therefore, disuse atrophy of the lateral pterygoid muscles was less signi cant than that in other masticatory muscles.…”

Magnetic resonance imaging evaluation of masticatory muscle changes in patients with primary trigeminal neuralgia before microvascular decompression

“…[12] The masticatory muscles play the role of moving the mandible, while the lateral pterygoid muscles are the only muscles that depress the mandible, and cannot trigger an attack of pain. [4,13] Therefore, disuse atrophy of the lateral pterygoid muscles was less significant than the other masticatory muscles.…”

Sleep analysis results of portable polysomnography in patients with acute and chronic temporomandibular disorder

“…The pathophysiological mechanism of TMD has shifted from a mechanistic-based theory to a biopsychosocial model, particularly in patients with chronic TMD [ 23 , 24 ]. In the present study, the distribution of TMD contributing factors, such as bruxism and history of macrotrauma, did not differ significantly between acute and chronic TMD.…”