Abstract
BACKGROUND: Ignoring this anatomic structure would have implications for iatrogenic perforation with the trocar toward the FH during the initial blind drilling or due to the diffusion of the infusion liquid toward the middle ear. PURPOSE: To analyze the prevalence of the FH in an institutional population with a high incidence of TMD to provide further guidelines in diagnosing this anomaly and the planification of TMJ arthroscopy. MATERIALS AND METHODS: A retrospective tomographic study was conducted at the ENT-Oral and Maxillofacial and Radiology Department of the Hospital Universitario la Samaritana in Bogotá, Colombia. Inclusion criteria were patients over 18 years of age who had complementary exams such as ear, face, paranasal sinus, and/or TMJ tomography. Exclusion criteria were history of direct trauma to the external auditory canal in the medical history, patients with craniofacial syndromes, congenital anomalies, and/or history of cranial, mandibular, or temporal fractures. Two radiologists were part of the evaluators of the CT images who conducted the measures in the axial tomographic section and established the presence of the tympanic defect. RESULTS: A sample size of 139 medical records of patients, where females represent n: 101 (72.6%) and males represent n: 38 (27.4%). The average age was 43 years ± 18 years. Among the studied population, a total of five FH were detected, corresponding to a prevalence of 3.6% (95% CI 1.5-8.1%). The average size of the defect was 3.52 mm ± 1.1 mm. All the patients had TMJ-related symptoms, but none of them reported otalgia. CONCLUSION: The initial evaluation of each patient must be addressed to assess the integrity of the tympanic bone. In this study, the defects size was smaller than others previously reported. However, diffusion through the tympanic defect could spread the lavage substance into the middle ear during TMJ arthroscopic surgery.