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

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.

FORAMINA OF THE POSTERIOR CRANIAL BASE: A STUDY OF ADULT INDIAN SKULLS. 89 Las foraminas de la base posterior del cráneo: Un estudio en cráneos de indios adultos

Introducción: Las foraminas craneales son los únicos puntos de entrada a un cráneo que, de otra manera, permanecería cerrado. La evaluación de estas foraminas es una parte muy importante para el diagnóstico médico y debería ayudar al clínico en su enfoque quirúrgico a esta delicada región. El presente estudio se centra en las foraminas de la base posterior del cráneo incluyendo los pares de fosas yugulares, el agujero estilomastoideo, el canal hipogloso; el impar agujero magno y otras foraminas auxiliares tales como el agujero mastoideo y el canal condíleo posterior. Material y Método: El estudio se llevo a cabo en 50 cráneos adultos, secos y macerados, pertenecientes todos ellos al subcontinente indio. Para ello se utilizó un calibre vernier con una precisión de 0.01 mm. Resultados: Se obtuvo una amplia variación en las dimensiones de la fosa yugular. La diferencia máxima bilateral en el mismo cráneo fue de 6.72 mm. La bóveda y la septación incompleta existían en un 20% de los cráneos. El tamaño del agujero estilomastoideo osciló entre 0.9-5.3 mm. Una de las 100 foraminas estudiadas se mostró estenosada. La duplicación se vio en el 4% de los cráneos. Las septaciones en el canal hipogloso se produjeron exclusivamente en el aspecto endocraneal y se observó bilateralmente en un 4% y unilateralmente en un 20% de los cráneos. En uno de los cráneos se encontró occipitalización del atlas. La salida del agujero magno estaba deformada y estenosada. Este fue el único cráneo con un índice en el agujero magno menor de 1. El agujero mastoideo estuvo presente bilateralmente en un 74% y unilateralmente en un 16% de los cráneos, mientras que las cifras correspondientes para el canal condíleo posterior fueron de 62% y 26% respectivamente. Introduction: Cranial foramina are the only portals to an otherwise closed cranium. Evaluation of these foramina is an important part of diagnostic medicine and would aid the clinician in his surgical approach to this complicated region. The present study is of foramina in the posterior cranial base including the paired jugular foramen, stylomastoid foramen, the hypoglossal canal; the unpaired foramen magnum and accessory foramina such as the mastoid foramen and the posterior condylar canal. Materials and Method: The study was done on 50 dried, macerated, adult human skulls, all belonging to the Indian subcontinent, using a vernier caliper with a precision of 0.01 mm. Results: There was wide variation in the dimensions of the jugular foramen. The maximum bilateral difference within the same skull was 6.72mm.Dome and incomplete septation coexisted in 20% skulls. The size of stylomastoid foramen ranged from 0.9-5.3 mm. One out of the 100 foramina studied showed a stenosed foramen. Duplication was seen in 4% skulls. Septations in the hypoglossal canal were exclusively on the endocranial aspect and were seen bilaterally in 4% and unilaterally in 20% skulls. In one skull there was occipitalisation of the atlas. The magnum outlet was distorted and stenosed. This was the only skull with a ‘foramen magnum index’ less than 1. The mastoid foramen was present bilaterally in 74% and unilaterally in 16% skulls while the corresponding figures for the posterior condylar canal were 62% and 26% respectively.

Occipital artery occlusion to facilitate transmastoid posterior fossa tumor embolization

ABSTRACTThe transmastoid branch of the occipital artery is an important supply to posterior fossa vascular malformations and tumors and is often difficult to catheterize due to tortuosity and a transforaminal course. In very difficult situations, we can try to induce spasm of the occipital artery just beyond the origin of the mastoid branch by repeated passages of the microcatheter/wire. This induces a temporary ‘ligation’ like effect so that the microcatheter can then be manipulated into the mastoid branch via the mastoid foramen. Rarely, the occipital artery has to be sacrificed if spasm cannot be induced or is short living, following which particles can be injected from a distance without entering the mastoid foramen. Occluding the occipital artery proximally has no effect on distal perfusion, as collaterals and anastomoses from superficial temporal artery, posterior auricular artery, and opposite occipital artery take over the supply.

Transcranial puncture through the parietal and mastoid foramina for the treatment of dural fistulas

✓ In this report the authors describe the endovascular treatment of dural arteriovenous fistulas (DAVFs) through trans-cranial puncture of the feeding arteries. Four patients had DAVFs that were fed by occipital arteries (OAs) that supplied blood to the intracranial meningeal arteries via the transcranial branches and coursed through the parietal and mastoid foramina. Due to the excessive tortuosity of the OA, conventional endovascular navigation had failed in all cases. Transcranial puncture of the meningeal feeding arteries was performed through the parietal or mastoid foramen, allowing navigation with a microcatheter until the level of the shunts. Complete cure of the DAVF was attained in all patients after injection of acrylic glue.