The Role of Magnetic Resonance Imaging of the Temporomandibular Joint to Investigate Tinnitus in Adults with Temporomandibular Joint Disorder: A Comparative Study

Original Research The Role of Magnetic Resonance Imaging of the Temporomandibular Joint to Investigate Tinnitus in Adults with Temporomandibular Joint Disorder: A Comparative Study Danielle Lavinsky1  http://orcid.org/0000-0001-6742-2150 Joel Lavinsky2  Enio Tadashi Setogutti3  Daniela Disconzi Seitenfus Rehm4  Luiz Lavinsky1  1 Department of Surgical Sciences, Graduate Program in Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil 2 Department of Otorhinolaringology, Clinica Lavinsky, Porto Alegre, RS, Brazil 3 Department of Magnetic Resonance Imaging, Hospital Ernesto Dornelles, Porto Alegre, RS, Brazil 4 Department of Temporomandibular Disorder and Orofacial Pain, Associação Brasileira de Odontologia, Porto Alegre, RS, Brazil Abstract Introduction The prevalence of tinnitus is higher in individuals with temporoman- dibular joint disorder (TMD) than in the general population. Magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) is the method of choice for investigation, and it has been hypothesized that specific MRI findings might be observed in TMD with comorbid tinnitus. Objective To comparatively describe MRI findings in patients with TMD with and without tinnitus, identifying the most common TMJ alterations and determining whether a correlation exists between severity of TMD and tinnitus. Methods A cross-sectional study of 53 adult patients with bilateral or unilateral TMD (30 with and 23 without tinnitus). The association between tinnitus and morphological aspects of TMD (changes in condylar morphology, articular eminence morphology, and disc morphology), disc displacement (with/without reduction), condylar translation, and intra-articular effusion was analyzed on MRI images. Results The mean patient age was 46.12 ± 16.1 years. Disc displacement was the most common finding in both groups (24 patients with tinnitus versus 15 without; p = 0.043). Only the frequency of disc displacement with reduction was significantly different between groups. Conclusion Additional imaging techniques should be explored to detect specific aspects of the relationship between tinnitus and TMD. Keywords: magnetic resonance imaging; temporomandibular joint; temporomandibular joint disorders; tinnitus Introduction The temporomandibular joint (TMJ), which is among the most complex joints in the human body,1 is routinely exposed to considerable loads, as indicated by animal, in vitro, and mathematical models.2 With time, such exposure, alone or associated with underlying disorders, is thought to generate physiological and pathological changes,3 which may lead to temporomandibular joint dysfunction (TMD) of varying complexity and magnitude.4 5 6 7 The most common symptoms reported by patients with TMD include pain, deviations or restrictions in the range of motion, presence of clicking, crackling, or popping sounds,8 and otologic symptoms such as tinnitus,9 defined as a phantom sound in the absence of an external source.10 The prevalence of tinnitus is higher in individuals with TMD than in the general population.5 Neither TMD nor tinnitus are life-threatening, but both can cause great distress.3 10 11 Although the pathogenesis of the relationship between TMD and tinnitus is poorly understood, a common etiological mechanism has been suggested.12 Therefore, the investigation of findings peculiar to TMD patients with tinnitus may be useful to clarify the link between these two entities, and may shed light on the mechanisms involved in the onset of TMD and tinnitus. Magnetic resonance imaging (MRI) of the TMJ is the method of choice for investigation of TMD.13 It has been hypothesized that specific MRI findings might be observed in TMD with comorbid tinnitus.14 Thus, the aim of the present study was to comparatively describe MRI findings in patients with TMD with and without tinnitus, identifying the most common TMJ alterations and determining whether a correlation exists between the severity of TMD and tinnitus. Methods The project was approved by our local institutional review board. All procedures were in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This cross-sectional comparative study analyzed chart data and imaging findings. All investigators signed a data use agreement that ensured anonymity. The inclusion criteria were age > 17 years and diagnosis of TMD,15 16 based on clinical symptoms including pain, clicking or crackling sounds, and mandibular opening with deviation. The exclusion criteria were objective tinnitus; tinnitus with a diagnosed etiology; Ménière disease; noise-induced hearing loss, ear surgery, or infections; and abuse of ototoxic medications or substances (furosemide, aspirin) or stimulants. Individuals with certain systemic diseases (diabetes, hypothyroidism) were also excluded. Between 2009 and 2016, adult patients of both genders, with bilateral or unilateral TMD, were selected for the study. Patients with tinnitus and a clinical history of TMD were referred by their otologist to the investigator (a dentist specializing in TMD and orofacial pain) after other otologic comorbidities had been ruled out. Patients with TMD who did not have tinnitus were either referrals from otologists or other specialists or were walk-ins to our service. All patients in both groups underwent a clinical and dental assessment and MRI evaluation of the TMJ. TMJ Evaluation Temporomandibular joint evaluation was performed by the same examiner (DLB) in all patients. Mandibular range of motion was measured as described by Emshoff et al.15 Briefly, maximum opening (measured in mm from the central maxillary incisor to the opposing mandibular incisor) and lateral excursions (relative to the maxillary midline, with the teeth slightly separated) were evaluated. The TMJ was auscultated with a stethoscope to detect unilateral or bilateral clicks during three openings and three lateral and protrusive movements. Disc displacement with reduction was identified in the presence of a click in the TMJ during vertical mandibular motion and lateral or protrusive excursions and normal closing with or without clicking, reproducible on two of three occasions. Disc displacement without reduction was defined as a history of sudden reduction in mandibular opening, maximum unassisted mandibular opening 35 mm, and mandibular opening with assistance increased by 3 mm or less over maximum unassisted opening. Otologic Evaluation Patients reporting tinnitus underwent a full ear, nose and throat (ENT) investigation, including pure tone audiometry, to identify the underlying etiology (ear or systemic disorder). If a retrocochlear disorder was suspected, an evoked potential audiometry was performed. If a systemic cause was suspected, a laboratory workup was performed (metabolic, hormo (...truncated)