Selective embolization of the mastoid emissary vein for pulsatile tinnitus treatment: when is it indicated?

BACKGROUND: Venous pulsatile tinnitus (PT) can be caused by the perception of blood flow through the mastoid emissary vein (MEV). However, the causal relationship of this anomaly has not been established as selective occlusion of this vein has never been performed. The aim of this study was to report on a small series of patients suspected of having PT caused by an MEV, who underwent MEV embolization as treatment for PT, and to identify the correct indications for this procedure. METHODS: This was a single center retrospective study (CNIL 2215065) including six patients with isolated disabling PT treated by embolization of the MEV, recruited between December 2017 and August 2019. Patient charts were systematically reviewed. All patients underwent non-contrast temporal bone CT and MRI. RESULTS: Mean age of the patients (five women, one male) was 56.3 years (range 40-71 years). Two patients presented with venous PT and four had neutral PT. The MEV was in direct contact with the mastoid air cells on temporal bone CT in all patients. Based on clinical examination, two patients presented with venous PT while four patients had neutral PT. In all cases of venous PT, selective embolization of the MEV caused the tinnitus to disappear, suggesting technical success. In contrast, embolization of the MEV had no effect in patients with neutral PT. CONCLUSIONS: We demonstrated that MEV could be a source of venous PT. Embolization of the MEV was effective only in cases of clinical venous PT.

Periosteal Flap in Cochlear Implantation, How I Do It?

This clinical report describes and evaluates a novel periosteal flap design. This technique was applied in 26 patients who underwent cochlear implantation surgery at two tertiary referral centers. No complications were observed during or after the surgery. Additionally, there was no evidence of device migration, wound infection, wound hematoma, or delayed wound healing. Notably, the mastoid emissary vein was intact in all cases. In conclusion, this modified anterior-based periosteal flap is a safe procedure and is aimed at avoiding mastoid emissary vein bleeding and allowing complete repositioning of the periosteum over the implanted device.

Landmarks for the preservation of the middle temporal artery during mastoid surgery: Cadaveric dissection study.

IMPORTANCE: The middle temporal artery flap is a vascularized periosteal flap that is highly useful for otologic reconstruction including the middle cranial fossa, mastoidectomy defect, and external auditory canal. The course of the artery is close to the external auditory canal and is easily injured during preliminary exposure and elevation of flaps. OBJECTIVES: To describe the course of the middle temporal artery in relation to the external auditory canal and the superficial temporal artery in order to enhance preservation and use in otologic reconstruction. DESIGN: Dissection of preserved, injected cadaveric temporal bones. SETTING: Anatomical laboratory. PARTICIPANTS: Seven cadaveric temporal bones. INTERVENTION: Temporal bones were dissected in a planar manner to identify the middle temporal artery along the squamous temporal bone to its origin. The superior border of the external auditory canal was divided, horizontally, into thirds to create three measurement points. Distances between the middle temporal artery and the bony portion of the external auditory canal were then determined. MAIN OUTCOMES AND MEASURES: Horizontal diameter of the external auditory canal, distance from the superior-most border of the external auditory canal to the middle temporal artery, various patterns of the middle temporal artery. RESULTS: The middle temporal artery branched from the superficial temporal artery in all specimens. Mean horizontal diameter of the external auditory canal was 9.97mm. Mean distances between the bony portion of the external auditory canal and middle temporal artery for the first, second, and third points along the horizontal diameter of the external auditory canal were 1.57, 2.96, and 4.02mm, respectively. In at least one specimen, the artery dipped into the external auditory canal. CONCLUSIONS AND RELEVANCE: The middle temporal artery runs closest to the external auditory canal at the anterosuperior border. To preserve the middle temporal artery for use in reconstruction after otologic surgery, the surgeon should avoid dissection superior to the external auditory canal until the artery is positively identified.

The mastoid emissary vein: an anatomic study with magnetic resonance imaging.

PURPOSE: The mastoid emissary vein (MEV) is a small venous channel connecting the intracranial and extracranial venous systems. Most current knowledge about the MEV has been obtained through cadaver studies. This study aimed to explore the MEV in vivo, using magnetic resonance imaging (MRI). METHODS: Ninety-six patients were enrolled in this study. The initial examinations used the conventional MRI sequences; contrast examinations were performed using thin-sliced sections. RESULTS: The MEVs were identified bilaterally in 59.3 % of the 96 patients and unilaterally in 29.2 %. The original site, size, and intraosseous course of the MEVs were highly variable. On coronal images, the MEVs originated from a variable height on the posterior wall of the sigmoid sinus, most frequently from the lower third of the wall. Intraosseous MEV courses were classified as straight, curved, or tortuous, with the straight type occurring most frequently. The MEVs were dominant on the right side in 51.8 % of cases and on the left side in 24.7 % of cases. Two patients had two MEVs on the same side. Furthermore, on eight sides (5.6 %), the diploic venous channel was found to communicate with the MEV. CONCLUSIONS: The MEV is a structure with diverse morphologies and right-sided dominancy. MEVs should be evaluated before performing surgical and endovascular procedures around the suboccipital region.

[STUDYING OF BIOMECHANICAL PROPERTIES OF SKIN IN THE MASTOID REGION WHILE THE COSMETIC OTOPLASTY PERFORMANCE].

The present methods for a droopy ears correction do not guarantee the optimal cosmetic effect achievement. Optimal borders of deformity in cutaneo-adiposal flap of the mastoid region while cosmetic otoplasty performance were studied. Basing on analysis of biomechanical investigations, there were determined the optimal corners of stretching and direction of the strength vector in cutaneo-adiposal flaps while otoplasty performance, securing conditions for surgical intervention performance with preservation of a natural topographo-anatomical ratios in the head and neck tissues.

[Blood flow measurement and clinical usefulness of the temporal fascial scar tissue flap and the periosteal scar tissue flap in posterior canal wall reconstructed tympanoplasty for the mastoid cavity problem in the postoperative ear].

In the postoperative ear, following reconstructive tympanoplasty for a mastoid cavity problem, a very important key is to maintain a stable reconstructed posterior canal wall with the bone plate and cartilage in the posterior canal wall. The authors manage reconstruction of the posterior canal wall with the temporal fascial scar tissue flap (TFSF) and the temporal periosteal scar tissue flap (TPSF) to ensure obtaining a stable posterior canal wall and a tympanic membrane graft. Well-vascularized TFSF and TPSF enable us to acquire a solid reconstructed posterior canal wall because of the secure blood supplies to the flaps. In order to investigate the blood supplies of TFSF and TPSF, we employed laser Doppler blood flowmeters and measured blood flow in the flaps in 20 cases of posyoperative ears treated for a mastoid cavity problem. The blood supplies to both flaps were good, with the blood supply to the TFSF being statistically better than in the case of the TPSF. These findings suggested that the TFSF and TPSF were a reliable source of local well-vascularized tissue which were pliable and could facilitate the creation of a stable posterior canal wall. Furthermore it seems the good blood supply was linked to the prompt postoperative healing, the avoidance of postoperative infection, and good hearing improvement postoperatively.

Prevalencia y características morfométricas del foramen mastoideo y vena emisaria mastoidea en población mexicana / Prevalence and morphometric characteristics of mastoid foramen and mastoid emmisary vein in the Mexican population

Las descripciones anatómicas del foramen mastoideo (FM) y la vena emisaria mastoidea (VEM) son escasas en la literatura. Dicho conocimiento es fundamental para realizar un abordaje quirúrgico de la fosa craneal posterior o región mastoidea. El objetivo del estudio fue determinar la prevalencia, variantes y características morfométricas del FM y VEM en población mexicana. Se evaluaron 176 hemicráneos por dos observadores independientes cegados el uno del otro, se determinaron la prevalencia, número y características morfométricas. La prevalencia del FM entre los dos lados fue de 75% con una mayor frecuencia de forámenes del lado izquierdo comparado con el lado derecho; respecto al número de forámenes se encontraron 108 hemicráneos con un foramen único, 22 con doble foramen y 2 con triple foramen. La prevalencia del FM y VEM fue de 75%, siendo la variante única la más frecuente.

The anatomic descriptions of mastoid foramen (MF) and mastoid emissary vein (MEV) are lacking in the literature. This knowledge is fundamental for the surgeon who is about to perform surgery of the posterior fossa or mastoid region. This study aims to determine the prevalence of MF and MEV in Mexican population, determine the morphometric characteristics of MF and describe possible variations in the number, size, location and asymmetry. In this study 88 craniums were evaluated (176 hemicranium) by two independent observers who did not have access to information of each other´s results. The prevalence, number and the morphometric characteristics were determined. MF prevalence of the two sides of the skull was 75 % with a higher frequency of the left foramina compared to the right side; in reference to the number of foramina we found 108 hemicranium with a single MF, 22 double and 2 triple foramen. In conclusion, the prevalence of MF and MEV in this study is 75%, this single variant noted as being the most frequent.

Mastoid emissary vein: anatomy and clinical relevance in plastic & reconstructive surgery.

The mastoid emissary vein (MEV) is an anatomical structure with limited description in the literature and its importance is even less recognized in the plastic surgical field. Investigations in its anatomy and physiology have described its anthropological significance in transition to bipedalism and preferential intracranial venous flow into the vertebral plexus in the upright man. Inadvertant injury of vessels of this size pose a significant problem due not only to difficulty with haemostasis but also from their bidirectional flow and close proximity to the sigmoid sinus where cases of thromboembolism have been described. Recognition of this common anatomical structure and how to manage bleeding from the vessel it is important for the surgeon operating in this area and even more so for the craniofacial surgeon who operates on complex craniosynostotic patients where the MEV may be the sole dominant drainage pathway of the brain. We conducted a study on 106 cadaveric dry skull specimens looking at the incidence, position and caliber of mastoid emissary foramina. 83.7% of skulls were found to have at least one foramen with a mean diameter of 1.64 mm and the largest specimen measuring 7 mm.

Pulsatile tinnitus caused by a dilated mastoid emissary vein.

Although pulsatile tinnitus can be audible, objective demonstration of this heartbeat-synchronous sound has rarely been successful. We report a rare case of pulsatile tinnitus in a 44-yr-old female patient, which was induced by a large mastoid emissary vein (MEV) and objectively documented by Doppler sonography of the left posterior auricular region. The tinnitus was intermittent and the patient could adapt to the tinnitus without intervention on the mastoid emissary vein. These findings suggest that a single large MEV can cause pulsatile tinnitus in the absence of other vascular abnormalities, and imaging studies of the posterior fossa and Doppler ultrasonography can aid the diagnosis in such cases.

Micro-channels in the mastoid anatomy. Indications of a separate blood supply of the air cell system mucosa by micro-CT scanning.

The mastoid air cell system has traditionally been considered to have a passive role in gas exchange and pressure regulation of the middle ear possibly with some acoustic function. However, more evidence has focused on the mucosa of the mastoid, which may play a more active role in regulation of middle ear pressure. In this study we have applied micro-CT scanning on a series of three human temporal bones. This approach greatly enhances the resolution (40-60 µm), so that we have discovered anatomical details, which has not been reported earlier. Thus, qualitative analysis using volume rendering has demonstrated notable micro-channels connecting the surface of the compact bone directly to the mastoid air cells as well as forming a network of connections between the air cells. Quantitative analysis on 2D slices was employed to determine the average diameter of these micro-channels (158 µm; range = 40-440 µm) as well as their density at a localized area (average = 75 cm(-2); range = 64-97 cm(-2)). These channels are hypothesized to contain a separate vascular supply for the mastoid mucosa. However, future studies of the histological structure of the micro-channels are warranted to confirm the hypothesis. Studies on the mastoid mucosa and its blood supply may improve our knowledge of its physiological properties, which may have important implications for our understanding of the pressure regulation of the middle ear. This article is part of a special issue entitled "MEMRO 2012".

Pulsatile Tinnitus Caused by a Dilated Mastoid Emissary Vein

Although pulsatile tinnitus can be audible, objective demonstration of this heartbeat-synchronous sound has rarely been successful. We report a rare case of pulsatile tinnitus in a 44-yr-old female patient, which was induced by a large mastoid emissary vein (MEV) and objectively documented by Doppler sonography of the left posterior auricular region. The tinnitus was intermittent and the patient could adapt to the tinnitus without intervention on the mastoid emissary vein. These findings suggest that a single large MEV can cause pulsatile tinnitus in the absence of other vascular abnormalities, and imaging studies of the posterior fossa and Doppler ultrasonography can aid the diagnosis in such cases.

Persistence of multiple emissary veins of posterior fossa with unusual origin of left petrosquamosal sinus from mastoid emissary.

Emissary veins are valveless veins which pass through the cranial apertures and connect the dural venous sinuses and the extracranial veins. The clinical importance of emissary veins is increasingly being appreciated. Some emissary veins like the petrosquamosal sinus and mastoid emissary vein may cause significant bleeding during middle ear and skull base surgeries. A dilated mastoid emissary vein or condylar emissary vein can sometimes be a rare cause of tinnitus. Radiological identification of these venous channels has been described in recent years and assumes significance in light of their clinical importance. We describe the CT and MRI findings of a rare case that had persistence of multiple emissary veins and presented clinically with tinnitus. The radiological findings included a dilated left mastoid emissary vein, bilateral petrosquamosal sinuses, posterior condylar veins, occipital emissary veins and an intrapetrous venule. The left petrosquamosal sinus had an unusual origin from the dilated mastoid emissary vein. The patient also had major anomalies of posterior fossa venous sinuses which are discussed. A relevant review of literature is included.

Clinical anatomy of the mastoid and occipital emissary veins in a large series.

INTRODUCTION: Detailed descriptions of the mastoid emissary veins (MEVs) and the foramina through which they travel are lacking in the literature. Therefore, the aim of our study was to explore and delineate the morphology, topography and morphometry of the MEV, mastoid foramen (MF) and occipital foramen (OF). One hundred cadaver heads and 100 dried human skulls were grossly examined RESULTS: The MF and OF varied from being absent to having as many as four small openings, each transmitting an emissary vein. The overall prevalence of MEV was 98% on the right and 72% on the left. The overall prevalence of OF was 7% on the right and 4% on the left. The mean length of the MEV from its point of origin to its point of termination was found to be 7.2 cm with a range of 3.8-11.8 cm. The mean diameter of the MEV at the mastoid emissary foramen was 3.5 mm with a range of 1.1-5.6 mm. In the majority of the cadavers (85%) it was observed that mastoid and occipital emissary veins formed a confluent venous system, while in the remaining 15%, they remained as single vessels. CONCLUSIONS: The MEV may be a significant source of bleeding during surgery of the skull base or middle ear, particularly during retrosigmoid and far-lateral approaches and detailed anatomical knowledge may help to prevent these complications. Endovascular treatment of dural arteriovenous fistulas is often extremely difficult due to limited access, however, the use of the MEV represents a unique and potentially valuable technique for accessing an isolated or inaccessible transverse or sigmoid sinus system.

Anomalous intracranial venous drainage associated with basal ganglia calcification.

We describe the neuroradiologic findings in a 7-year-old boy with anomalous intracranial venous drainage and cerebral calcification. CT scans demonstrated that his scalp mass was a plexus of scalp veins filled through the emissary foramen, and there were cerebral calcifications. Angiography revealed bilateral sigmoid sinus atresia with most of the intracranial venous drainage via the prominent mastoid emissary veins into dilated scalp vein. The possible relationship between cerebral calcification and anomalous intracranial venous drainage is discussed.

Percutaneous transvenous embolization of a dural arteriovenous fistula through a mastoid emissary vein. Technical note.

Definitive endovascular treatment of dural arteriovenous fistulas (DAVFs) requires obliteration of the site of the fistula: either the diseased dural sinus or the pial vein. Access to this site is often limited by occlusion of the sinus proximal and distal to the segment containing the fistula. The authors describe a technique in which the mastoid emissary vein is used to gain access to a Borden-Shucart Type II DAVF in the transverse-sigmoid sinus. Recognition of this route of access, if present, may facilitate endovascular treatment of these lesions. Access to the transverse sinus via this approach can be straightforward and may be underused.

Objective assessment of the perineural vascular plexus as a landmark for the horizontal part of the facial nerve in middle ear and mastoid surgery.

OBJECTIVE: To objectively evaluate the usefulness and the reliability of the perineural vascular plexus as a landmark for identification of the facial nerve in surgery for chronic squamous otitis media. STUDY DESIGN: Prospective case series. SETTING: Tertiary otologic center. PATIENTS: Seventy consecutive patients requiring surgery for cholesteatomatous otitis media. INTERVENTION: Use of a semiquantitative grading system intraoperatively to assess the utility and ease of using the perineural facial plexus as the pointer to the facial nerve. MAIN OUTCOME MEASURES: Description of the perineural vascular plexus and assessment of the reproducibility of the grading system. RESULTS: In 82.5% of patients, the plexus was used as the sole pointer to the level of the facial nerve, with other landmarks being used in the remaining 17.5%. A very prominent vessel was used to identify the nerve in 82.5%, therefore being classified as Grade 1. Multiple small vessels were seen in 15.8% (Grade 2), and in 1.5% the vessel plexus was thin and difficult to identify. The average measure intraclass correlation was 0.75 (95% confidence interval, 0.57-0.85), indicating excellent reproducibility of the system. CONCLUSION: We believe that the perineural vascular plexus is a dependable and reliable landmark for the level of the facial nerve in surgery for chronic otitis media.

[Applied anatomic study on blood supply for extracranial segment of facial nerve].

OBJECTIVE: To explore the arterial origin and the distribution of the extracranial branches of the facial nerve. METHODS: Red latex or red chlorinated polyvinyl chloride was injected into the arteries of 15 fresh adult head specimens by both common carotid artery catheterization. The arterial origin and distribution of the extracranial branches of the facial nerve were observed. RESULTS: The nutrient arteries of the extracranial branches of the facial nerve originated from stylomastoid artery of the posterior auricular artery, the facial nervous branch of superficial temporal artery, transverse facial artery, superior and inferior facial nervous branches of external carotid artery and the posterior and anterior facial nervous branches of external carotid artery. The outer diameters of them were (0.8 +/- 0.2) mm, (0.9 +/- 0.4) mm, (1.9 +/- 0.3) mm, (1.0 +/- 0.2) mm, (1.1 +/- 0.4) mm, (1.0 +/- 0.2) mm and (1.1 +/- 0.6) mm respectively. The sub-branches of the attendant artery of the facial nerve anastomosed each other in addition to supplying their own nerve, and a rich vascular network was formed between the facial nerve and adjacent tissue. CONCLUSION: The study on blood supply of the extracranial segment of the facial nerve can provide anatomic basis for avoiding injury of the nutrient arteries of the facial nerve during operation of the parotidean and masseteric region clinically.