Evaluation of the Mastoid Emissary Canals with Computerized Tomography in Patients with Chronic Otitis Media

Abstract

Background The mastoid emissary veins (MEVs) pass through the mastoid emissary canal-mastoid foramen (MEC-MF) in the mastoid region of the skull. MEVs can give rise to complications during surgical procedures. The purpose of our study was to investigate the morphological and morphometric characteristics of MECs of patients with clinical chronic otitis media (COM) using high-resolution computed tomography (HRCT). Methods Patients diagnosed with COM and undergoing temporal HRCT were identified by retrospectively scanning our hospital's automation system. Patients undergoing temporal HRCT for reasons other than COM, infection or tinnitus were identified for the control group by scanning the PACS archive. Sixty-two mastoid regions were examined in 38 unilateral and 12 bilateral COM patients, and 100 mastoid regions in the 50 patients in the control group. The presence of an accessory MEC-MF and MEC-MF diameters was evaluated in both groups. Results Main MEC diameters on the side of the ear with COM were 1.6 mm, and total accessory and main MEC diameters were 1.8 mm, both values being significantly higher than in the control group. Presence of accessory MEC on the side of the ear with COM was determined at 61.8%, significantly higher than in the control group. Conclusion Preoperative awareness of cranial venous drainage abnormalities is important to reduce surgical complications. Our study shows that MECs may be wider in diameter in patients with COM. MECs in COM patients must be identified before surgery to the mastoid region.

Emissary veins and foramina: topography, incidence, and clinical significance

“…These canals in these patients must be CTassessed before surgery in the mastoid region. 24 Venous abnormalities in the region of the temporal bone as large emissary veins, ipsilateral hypoplastic sigmoid venous sinus or jugular foramen, aberrant petrosal sinuses, and jugular bulb abnormalities are common features in CHARGE syndrome. Recognition of these abnormal venous structures during ear surgeries is crucial to avoid fatal bleeding.…”

Morphometric and morphological evaluation of mastoid emissary canal using cone-beam computed tomography

“…The cranial emissary veins (CEVs) are venous structures that link the intracranial and extracranial venous systems in the posterior cranial fossa. 1 , 2 The emissary veins (EV) are located in the posterior cranial fossa, pass through the emissary ducts, and provide venous drainage through the dural venous sinuses. 3 Mastoid emissary canals are small, slender channels connecting the temporal bone's mastoid air cells to the external environment.…”

“…The canals run in a curved path, typically lateral and posterior, and terminate with a small opening on the posterior surface of the mastoid process. 2 , 3 Some of these veins show many variations within the skull and have their foramen, while others connect the extracranial vessels and intracranial vessels through different canals. In the embryological period, these canals developed from the budding of the dural venous sinus.…”

Effect of Emissary Vein on Hemodynamics of the Transverse- Sigmoid Sinus Junction

“…Emissary veins (EVs) are valveless channels between the dural venous sinuses and extracranial venous structures, although most of EVs are inflow, bidirectional flow and turbulence are possible under an increase in intracranial pressure ( Mortazavi et al, 2012 ; Reardon and Raghavan, 2016 ). Most reports concerning EVs relate to the possibility of intraoperative iatrogenic bleeding ( Ozen and Sahin, 2020 ). Three EVs communicate with the TS-SS junction or SS: the mastoid EV (MEV), the petrosquamosal sinus and the posterior condylar EV.…”

“…Three EVs communicate with the TS-SS junction or SS: the mastoid EV (MEV), the petrosquamosal sinus and the posterior condylar EV. These veins are found in more than 80% ( Pekcevik et al, 2014 ; Gulmez Cakmak et al, 2019 ; Ozen and Sahin, 2020 ), 11.1% ( Pekala et al, 2018 ), and 76.5% ( Pekcevik et al, 2014 ) of the population, respectively, and their diameter varies from less than 1 mm to more than 5 mm. All three have been reported as causes of PT ( Lambert and Cantrell, 1986 ; Lee et al, 2013 ; Liu et al, 2013 ), and the sound may be totally eliminated after ligation.…”