The Laryngoscope V C 2015 The American Laryngological, Rhinological and Otological Society, Inc. Do the Angle and Length of the Eustachian Tube Influence the Development of Chronic Otitis Media? Aykut Erdem Dinc¸, MD; Murat Damar, MD; Mehmet Birol U gur, MD; Ibrahim Ilker € Oz, MD; Sultan S ¸evik Elic¸ora, MD; Sultan Bis¸kin, MD; Hakan Tutar, MD Objectives/Hypothesis: To compare the eustachian tube (ET) angle (ETa) and length (ETl) of ears with and without chronic otitis media (COM), and to determine the relationship between ET anatomy and the development of COM. Study Design: A retrospective case-control study. Methods: The study group comprised 125 patients (age range, 8–79 years; 64 males and 61 females) with 124 normal ears and 126 diseased ears, including ears with chronic suppurative otitis media (CSOM) with central perforation, intratym- panic tympanosclerosis (ITTS), cholesteatoma, and a tympanic membrane with retraction pockets (TMRP). ET angle and length were measured using computed tomography employing the multiplanar reconstruction technique. Results: The ETa was significantly more horizontal in diseased versus normal ears of all study groups (P 5.030), and there was no group difference in ETl (P 5.160). ETl was shorter in CSOM versus ITTS ears and normal ears (P 5.007 and P 5.003, respectively) and in cholesteatoma versus TMRP ears (P 5.014). In the unilateral COM group, there were no signifi- cant differences in the ETa or ETl of diseased versus contralateral normal ears (P 5.155 and P 5.710, respectively). The ETa was significantly more horizontal in childhood-onset diseased versus normal ears (P 5.027), and there was no group differ- ence in ETl (P 5.732). The ETa (P 5.002) and ETl (P <.001) were significantly greater in males than females. Conclusions: A more horizontal ETa and shorter ETl could be contributory (though not significantly) etiological factors in the development of COM. Key Words: Eustachian tube anatomy, chronic otitis media etiology. Level of Evidence: 3b Laryngoscope, 125:2187–2192, 2015 INTRODUCTION The eustachian tube (ET) performs three functions: ventilation, protection, and clearance of the middle ear. The ET also plays an important role in maintaining mid- dle ear physiology and functionality. 1 ET length (ETl) and angle (ETa) determine the likelihood of preventing nasopharyngeal reflux into the middle ear. 2 Chronic suppurative otitis media (CSOM) is a chronic inflammation of the middle ear cleft and mastoid mucosa, in which the tympanic membrane is not intact, and recurrent ear discharge or otorrhea is present. 2,3 The pathogenesis of CSOM is multifactorial; environ- mental and genetic factors, as well as the anatomical and functional characteristics of the ET, are all involved. 2 Infant ETs are shorter, with a more- horizontal ETa, compared with adult ETs 2,4 ; these ana- tomic features may underlie the increased susceptibility to otitis media with effusion (OME) and recurrent acute otitis media (AOM) observed in infants and children. CSOM in adults is predicted by recurrent AOM or chronic OME in childhood. 3 Studies linking the anatomical and functional char- acteristics of the ET with the pathogenesis of chronic oti- tis media (COM) have examined at risk populations, such as those with Down syndrome and craniofacial anomalies. These patients are at increased risk for developing ear disease as infants and young children due to their short, horizontal, and floppy ETs. 2 We found no histopathological or radiological studies analyzing the relationship between ET anatomy (angle and length in the anatomical position) and the development of COM. Tympanosclerosis (TS) is a disorder of the tympanic membrane and middle ear mucosa characterized by hya- linization and calcification of the submucosal connective tissue layer of the middle ear. 5 Although the exact etiol- ogy of TS has not been elucidated fully, it is widely accepted that TS commonly develops secondary to AOM and COM. Tympanic membrane retraction pockets are characterized by partial collapse of the mesotympanic or epitympanic cavities. 6 ET dysfunction and weakening of the tympanic membrane, due to OME, are major contrib- utors to retraction pocket development. 7 Cholesteatoma is a benign, gradually expanding, destructive epithelial lesion of the temporal bone that erodes adjacent bony structures, leading to various complications. ET From the Department of Otorhinolaryngology–Head and Neck Surgery (A.E.D., M.D., S.S.E., S.B.) and Department of Radiology (I.I.O.), B€ ulent Ecevit University Faculty of Medicine, Zonguldak, Turkey; and the Department of Otorhinolaryngology–Head and Neck Surgery (M.B.U., H.T.), Gazi University Faculty of Medicine, Ankara, Turkey. Editor’s Note: This Manuscript was accepted for publication February 3, 2015. The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Aykut Erdem Dinc¸, B€ ulent Ecevit Univer- sity Faculty of Medicine, KBB AD, 67600 Kozlu, Zonguldak, Turkey. E-mail: aykuterdem@yahoo.com DOI: 10.1002/lary.25231 Laryngoscope 125: September 2015 Dinc¸ et al.: Eustachian Tube Anatomy and COM 2187