Collet-Sicard syndrome caused by a paraganglioma in the region of the jugular foramen on one side: A case report and review.

Collet-Sicard syndrome is a rare neurological disorder caused by injury to the cranial nerve pairs IX, X, X, and XII. The author reports on a previously fit 27-year-old man who presented with dysphagia, choking on drinking water, hoarseness, weakness when turning the neck and shrugging the shoulders, and unexplained weight loss. Enhanced magnetic resonance imaging indicated a space-occupying lesion at the right jugular foramen. After surgical resection, the pathologic findings suggested a paraganglioma of the right jugular foramen and confirmed the diagnosis of Collet-Sicard syndrome. After postoperative treatment with a combination of acupuncture and modern medicine, the patient's symptoms significantly improved. This article analyzes previous literature regarding Collet-Sicard syndrome etiology and reports the case of a patient with a rare etiology, whose prognosis improved significantly after treatment with a combination of acupuncture and modern medicine.

Hypoglossal Canal Dural Arteriovenous Fistula: A Rare Cause of Ocular Proptosis.

It is exceedingly rare for dural arteriovenous fistulae (DAVFs) outside of the cavernous sinus to present with ophthalmological symptoms and signs. Hypoglossal canal DAVFs (HC-DAVFs) have only previously been reported as individual cases or small case series. Further, only an estimated 31% of HC-DAVFs present with ophthalmological findings. We report a noteworthy case of an HC-DAVF in a 74-year-old male who presented with proptosis, chemosis, and reduced visual acuity. He was treated endovascularly with liquid embolic filling. This report aims to highlight HC-DAVF as an important differential diagnosis for patients presenting with symptoms suggestive of arterialisation of the ophthalmic veins.

Fístula arteriovenosa dural del canal del hipogloso: reporte de caso y descripción de la anatomía / Dural arteriovenous fistula of the hypoglossal canal: case report and description of the anatomy

Introducción. Las fístulas durales arteriovenosas del canal del hipogloso (FDCH) son infrecuentes y suelen ser diagnosticadas tardíamente. Habitualmente se presentan con compromiso del par XII aunque pueden presentarse con síntomas diversos. Objetivos. Presentar un caso de FDCH que se presentó con proptosis y ojo rojo tratado por vía endovascular y describir la anatomía asociada. Descripción del caso. Un hombre de 51 años consultó por quemosis, exoftalmo y dolor ocular leve persistente durante un año. Las pruebas de imagen revelaron una lesión en la base del cráneo, sugestiva de malformación arteriovenosa, con drenaje hacia el bulbo yugular derecho y la vena oftálmica superior derecha. Se descartaron otras causas como tumores metastásicos. Intervención. Se realizó tratamiento por vía endovascular. Se utilizó un abordaje combinado arterial y venoso. La embolización arterial se hizo con un agente embolizante líquido de etilen vinil alcohol -logrando una oclusión parcial- y luego se completó la misma por vía venosa con hélices de platino (coils), logrando la oclusión total de la fístula. El paciente se recuperó favorablemente, con mejoría progresiva de los síntomas oculares. Experimentó una leve paresia del nervio XII derecha en el período postoperatorio inmediato, que se trató con corticoides. Fue dado de alta al quinto día. En el seguimiento a los 6 meses, la lesión no mostraba persistencia en las imágenes de resonancia magnética. Conclusión. Se presenta un caso de fístula dural arteriovenosa del canal del hipogloso tratada por vía endovascular con oclusión completa de la misma

Background. Dural arteriovenous fistulas of the hypoglossal canal are infrequent and are usually diagnosed late. They usually present with involvement of the XII cranial nerve, although they can present with various symptoms. Objectives. To present a case of dural arteriovenous fistulas of the hypoglossal canal that presented with proptosis and red eye treated endovascularly and describe the associated anatomy. Description of the case. A 51-year-old man presented with chemosis, exophthalmos, and mild eye pain that had persisted for one year. Imaging tests revealed a lesion at the skull base, suggestive of arteriovenous malformation, with drainage towards the right jugular bulb and the right superior ophthalmic vein. Other causes such as metastatic tumors were ruled out. Surgery. Endovascular embolization was performed to treat the dural arteriovenous fistula. A combined approach using arterial and venous was used. The arterial embolization was done with a liquid embolization agent of ethylene vinyl alcohol -achieving partial occlusion- and then was completed through a venous approach with platinum coils, achieving total occlusion of the fistula. The patient recovered favorably, with progressive improvement of ocular symptoms. He experienced mild right XII nerve palsy postoperatively, which was treated with steroids. He was discharged on the fifth day. At 6-month follow-up, the lesion showed no persistence on magnetic resonance images. Conclusion. A case of arteriovenous dural fistula of the hypoglossal canal treated endovascularly with complete occlusion is presented

Hypoglossal canal: an osteological and morphometric study on a collection of dried skulls in an Italian population: clinical implications.

BACKGROUND: The hypoglossal canal is a dual bone canal at the cranial base near the occipital condyles. The filaments of the hypoglossal nerve pass through the canal. It also transmits the meningeal branch of the ascending pharyngeal artery, the venous plexus and meningeal branches of the hypoglossal nerve. The hypoglossal nerve innervates all the intrinsic and extrinsic muscles of the tongue except the palatoglossal and is fundamental in physiological functions as phonation and deglutition. A surgical approach to the canal requires knowledge of the main morphometric data by neurosurgeons. METHODS: The present study was carried out on 50 adult dried skulls: 31 males: age range 18-85 years; 19 females: age range 26-79 years. The skulls came from the ''Leonetto Comparini'' Anatomical Museum. The skulls belonged to people from Siena (Italy) and its surroundings (1882-1932) and, therefore, of European ethnicity. The present study reports (a) the osteological variations in hypoglossal canal (b) the morphometry of hypoglossal canal and its relationship with occipital condyles. One skull had both the right and left hypoglossal canals occluded and, therefore, could not be evaluated. None of the skulls had undergone surgery. RESULTS: We found a double canal in 16% of cases, unilaterally and bilaterally in 2% of cases. The mean length of the right and left hypoglossal canals was 8.46 mm. The mean diameter of the intracranial orifice and extracranial orifice of the right and left hypoglossal canals was 6.12 ± 1426 mm, and 6.39 ± 1495 mm. The mean distance from the intracranial end of the hypoglossal canal to the anterior and posterior ends of occipital condyles was 10,76 mm and 10,81 mm. The mean distance from the intracranial end of the hypoglossal canal to the inferior end of the occipital condyles was 7,65 mm. CONCLUSIONS: The study on the hypoglossal canal adds new osteological and morphometric data to the previous literature, mostly based on studies conducted on different ethnic groups.The data presented is compatible with neuroradiological studies and it can be useful for radiologists and neurosurgeons in planning procedures such as transcondilar surgery. The last purpose of the study is to build an Italian anatomical data base of the dimensions of the hypoglossal canal in dried skulls..

A morphometric and morphological analysis of the foramen magnum, hypoglossal canal and occipital condyles in a select South African population.

BACKGROUND: The foramen magnum is a centralised structure found at the base of the skull. This orifice is a passageway that allows secondary structures, such as the medulla oblongata and meninges, to pass through. The occipital condyles is a small structure on either side of the foramen magnum, forming the craniovertebral joint. The hypoglossal canal is an orifice located on the occipital canal, providing a passageway for hypoglossal nerves. The study aimed to document the morphology and morphometry of the foramen magnum, occipital condyles and hypoglossal canals within a South African population. MATERIALS AND METHODS: Fifty skulls (n=50) were randomly selected from the Department of Clinical Anatomy, School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal. This study investigated the morphological and morphometric parameters of the foramen magnum, occipital condyles and hypoglossal canal. The morphometric parameters were measured using a digital Vernier calliper. The data was statistically analysed using SPSS, and a p-value of <0.05 was deemed statistically significant. RESULTS: The mean length and width of the foramen magnum was found to be 35.19mm and 27.77mm, respectively. The mean index of the foramen magnum was 1.3, which indicated that the foramen magnum was predominantly oval-shaped within the selected sample. The occipital condyles have a mean length and width of 21.73mm and 12.87mm, respectively. Furthermore, the most prevalent shape of the occipital condyles was oval. The mean length and width of the hypoglossal canals were 5.14mm and 3.87mm, respectively. While the most prevalent shape of the hypoglossal canal was oval and round on the right and left sides, respectively. CONCLUSIONS: The findings of this study may assist in reducing the risk of injury and mortalities during trans-condylar approach procedures.

Three-Dimensional Anatomy of the Hypoglossal Canal: A Plastinated Histologic Study.

OBJECTIVE: To provide a precise description of the morphology and morphometry of the hypoglossal canal (HC) and its relationship with surrounding structures by using the epoxy sheet plastination technique. METHODS: Thirty human cadaveric heads were plastinated into 5 sets of gross transparent plastination slices and 43 sets of ultrathin plastination sections. The HC were examined at both macro- and micro levels in these plastination sections and the reconstructed 3-dimensional visualization model. RESULTS: The HC was an upward arched bony canal with a dumbbell-shaped lumen. According to the arched trajectory of its bottom wall, the HC could be divided into a medial ascending segment and a lateral descending segment. The thickness of the compact bone in the middle part of the HC was thinner than that at the intracranial and extracranial orifices. In 14 of 43 sides (32.6%), the posterior wall or the roof of the HC were disturbed by passing venous channels which communicated the posterior condylar emissary vein and the inferior petroclival vein. The trajectory of hypoglossal nerve in HC is mainly from anterosuperior to posteroinferior. The meningeal dura and the arachnoid extended into the HC along the hypoglossal nerve to form the dural and arachnoid sleeves and then fused with the nerve near the extracranial orifice of the HC. CONCLUSIONS: Knowledge of the detailed anatomy of the HC can be helpful in avoiding surgical complications when performing surgery for lesions and the occipital condylar screw placement in this complex area.

Jugular foramen versus hypoglossal canal in axial CT scan.

Background: Differentiating jugular foramen from hypoglossal canal in computed tomography (CT) scan is vital for correct diagnosis of posterior fossa pathologies; however, it has been shown that the ability for differentiating these skull base elements is limited. The purpose of this study was to produce a simple algorithm for differentiating the jugular foramen from the hypoglossal canal in axial CT scan on two levels (top level where bony carotid canal is evident and lower level where bony carotid canal is not evident). Methods: Data derived from axial CT scan of 250 patients (500 sides) were used for producing algorithm. At top level petro-occipital fissure utilized for recognizing occipital condyle in which hypoglossal canal is located; and, at lower level the distance between the posterior border of the anatomic element (jugular foramen or hypoglossal canal) and the tangent to the anterior bony part is used for producing algorithm. Results: The mean age of patients was 38.1 ± 19 years. The petro-occipital fissure can be used in all patients for differentiating hypoglossal canal. At lower level the distance between the anterior tangent and the posterior border of the element was significantly lower for hypoglossal canal (P value < 0.001). The distance more than 3.5 mm with sensitivity 83.8% and specificity 97.1% differentiate jugular foramen from hypoglossal canal. Conclusion: Simple algorithms based on quantitative morphologic features of the jugular foramen and hypoglossal canal can be used with high sensitivity and specificity to distinguish these elements.

Retrospective evaluation of the morpometric and morphological anatomy of the occipital condyle, hypoglossal canal and foramen magnum in Turkish populaton with CBCT.

PURPOSE: The aim of this study is to morphometrically and morphologically examine the occipital condyle, which is an important anatomical region in terms of surgery and forensic medicine, and its surrounding structures, to evaluate the change in mean values according to gender and age, and to evaluate the correlation of the measurements obtained. METHODS: 180 (90 men, 90 women) CBCT images selected from the archive of Ankara University Faculty of Dentistry. Occipital Condyle length and width, Hypoglossal Canal-Basion distance, Hypoglossal Canal-Opistion distance, Hypoglossal Canal-Occipital Condyle anterior and posterior border distance, Occipital Condyle thickness, Hypoglossal Canal length, the widest diameter of Hypoglossal Canal, the narrowest diameter of the Hypoglossal Canal, the length of the Jugular Tubercle, the width of the Jugular Tubercle, the anterior intercondylar distance, the posterior intercondylar distance, and the Foramen Magnum index were measured. At the same time, the presence of septum or spicule in the hypoglossal canal and protrusion of the occipital condyle were evaluated. The relationship of age, gender, anterior and posterior intercondylar distance, and foramen magnum index measurements with all measurements were examined. RESULTS: In our study, all measurements were repeated 1 month after the first measurements to evaluate the intra-observer agreement, and the agreement between the obtained measurements and the first measurements was evaluated by calculating the intraclass correlation coefficient and 95% confidence intervals. Men's measurements were found to be significantly higher than women's measurements. When the coefficients of concordance in all measurements were examined, it was observed that there was a perfect concordance. CONCLUSION: When the results of the study are evaluated, it is seen that the values ​​obtained are generally close to the studies related to CT. Considering this, an idea can be gained as to whether CBCT, which has a lower dose and less cost, can be used as an alternative to CT in studies to be conducted with more comprehensive and different methods in skull base surgical planning.

Targeted transvenous embolization of a dural arteriovenous fistula at the jugular tubercle venous complex.

Background: Dural arteriovenous fistulas (dAVFs) occurring near the hypoglossal canal are rare. Detailed evaluation of vascular structures can identify shunt pouches at the jugular tubercle venous complex (JTVC) in the bone near the hypoglossal canal. Although the JTVC has several venous connections, including the hypoglossal canal, there have been no reports of transvenous embolization (TVE) of a dAVF at the JTVC using an approach route other than the hypoglossal canal. This report describes the first case of complete occlusion with targeted TVE using an alternative approach route in a 70-year-old woman presenting with tinnitus diagnosed with dAVF at the JTVC. Case Description: The patient had no history of head trauma or other preexisting conditions. Magnetic resonance imaging (MRI) showed no abnormal findings in the brain parenchyma. Magnetic resonance angiography (MRA) revealed a dAVF near the ACC. The shunt pouch was located in the JTVC, near the left hypoglossal canal, with feeders from the bilateral ascending pharyngeal arteries and occipital arteries, left meningohypophyseal trunk, and odontoid arch of the left vertebral artery. TVE was performed near the shunt pouch. Localized packing of the shunt point was achieved. The patient's tinnitus improved. Postoperative MRI showed disappearance of the shunt without any complications. No recurrence was observed on MRA 6 months after treatment. Conclusion: Our results suggest targeted TVE is an effective treatment for dAVFs at the JTVC.

Surgical anatomy of hypoglossal canal for various skull base surgeries.

PURPOSE: Anatomical knowledge of the hypoglossal canal is very important in relation to drilling of occipital condyle, jugular tubercle etc. So, this study was conducted to identify various morphometric and morphological features of the hypoglossal canal and its distance from adjacent structures relative to stable and reliable anatomic landmarks. METHODS: The study was performed on 142 hypoglossal canals of 71 adult human dry skulls. The parameters measured were the transverse, vertical diameter, depth of the hypoglossal canal. The distances from the hypoglossal canal to the foramen magnum, occipital condyle and jugular foramen were also noted. In addition, the different locations of the hypoglossal canal orifices in relation to the occipital condyle were assessed. The different shapes and types of the hypoglossal canal were also noted. RESULTS: There was significant difference (p < 0.05) in measurements taken on the right and left sides in males and females. The intracranial orifice of hypoglossal canal was present in middle 1/3rd in 100% of occipital condyle for both genders. The extracranial orifice of the hypoglossal canal was found to be in the anterior 1/3rd in 99% and 93.7% for male and female, respectively. Simple hypoglossal canal with no traces of partition was found to be more in males and females. The most common shape noted was oval both in males and females (71.8% and 68.7% respectively). CONCLUSION: The results of the dimensions of the hypoglossal canal and its distance from other bony landmarks will be helpful for neurosurgeons to plan which surgical approaches should be undertaken while doing various surgeries in posterior cranial fossa.

Morphological analysis and morphometry of the occipital condyle and its relationship to the foramen magnum, jugular foramen, and hypoglossal canal: implications for craniovertebral junction surgery.

Anatomical knowledge of the occipital condyle (OC) and its relationships to surrounding structures is important for avoiding injury during craniovertebral junction (CVJ) surgeries. This study was conducted to evaluate the morphology and morphometry of OC and its relationship to foramen magnum, jugular foramen (JF), and hypoglossal canal (HC). Morphometric parameters including length, width, height, and distances from the OC to surrounding structures were measured. The oval-like condyle was the most common OC shape, representing for 33.0% of all samples. The mean length, width and height of OC were 21.3±2.4, 10.5±1.4, and 7.4±1.1 mm, respectively. Moreover, OC was classified into three types based on its length. The most common OC length in both sexes was moderate length or type II (62.5%). The mean distance between anterior tips and posterior tips of OC to basion, and opisthion were 11.5±1.4, 39.1±3.3, 25.2±2.2, and 27.4±2.7 mm, respectively. The location of intracranial orifice of HC was commonly found related to middle 1/3 of OC in 45.0%. JF was related to the anterior 2/3 of OC in 81.0%, the anterior 1/3 of OC in 12.5%, and the entire OC length in 6.5%. These morphological analysis and morphometric data should be taken into consideration before performing surgical operation to avoid CVJ instability and neurovascular structure injury.

Surgical disconnection of a hypoglossal canal dural arteriovenous fistula demonstrating rapid progression of medulla oblongata disturbance: illustrative case.

BACKGROUND: Dural arteriovenous fistulas of the hypoglossal canal (HCDAVFs) with dominant drainage to perimedullary veins are extremely rare. These patients are prone to develop slow and progressive myelopathy, however, their clinical course has not been fully elucidated. We report an unusual case of HCDAVF in which the patient demonstrated rapid progression of hemiplegia and respiratory insufficiency. OBSERVATIONS: An 82-year-old woman demonstrated motor weakness of the left extremities. T2-weighted magnetic resonance imaging showed a high intensity area in the right medulla oblongata and angiography revealed HCDAVF with dominant drainage to the anterior medullary vein through the anterior condylar vein. Within 3 days, her hemiparesis and respiratory function worsened, and she needed mechanical ventilation. Considering that venous congestion in the medulla oblongata could cause the symptoms, we immediately performed surgical obliteration of the anterior condylar vein. The disappearance of HCDAVF was confirmed by angiography and the patient was weaned from mechanical ventilation 3 days postoperatively. Her left hemiplegia gradually resolved and she was independent in daily life 8 months after the operation. LESSONS: HCDAVFs with dominant drainage to the perimedullary veins can demonstrate rapid progression of medulla oblongata disturbance. Early disconnection should be considered to provide an opportunity for substantial recovery.

Meningiomas Involving the Hypoglossal Canal: A Case Report and Literature Review.

We report a rare case of hypoglossal canal meningioma in a 65-year-old woman who presented with dysphagia. Neurological examination revealed left hypoglossal nerve palsy. Head computed tomography and magnetic resonance imaging revealed a lesion around the left hypoglossal canal. She underwent a total resection with a midline suboccipital transcondylar approach. There were no postoperative complications, and the hypoglossal nerve palsy improved. There was no recurrence nine months after the surgery. Choosing a surgical approach that considers the site of origin and extent of tumor extension is important.

Aberrant drainage of posterior condylar emissary vein and abnormal orifice of hypoglossal canal: surgical implications in the transcondylar fossa approach for VA-PICA junction aneurysm.

BACKGROUND: The posterior condylar emissary vein (PCEV) and posterior condylar canal (PCC) are anatomical landmarks for identifying important structures like jugular tubercle and occipital condyle in surgical approach to the foramen magnum and condylar fossa. Several anatomical variations have been described. Drainage into the jugular bulb is found to be commonest. METHOD: A 70-year-old patient with unruptured vertebral artery-posterior inferior cerebellar artery (PICA) junction aneurysm-underwent surgical clipping via transcondylar fossa approach. RESULT: Preoperative computed tomography demonstrated an abnormal communication existed between the left-sided PCC and hypoglossal canal (HC). The PCEV was identified draining into a dilated venous channel/pouch at the "hip" of sigmoid sinus (junction of sigmoid sinus and jugular bulb). Intra-operatively, an occipital artery-PICA bypass was performed. The PCEV was skeletonized, coagulated, and divided to achieve hemostasis. The lateral and cranial drilling around PCC was successful at safeguarding the underlying contents of HC (in medial and caudal extent). CONCLUSION: Preoperative angiography and detailed morphometric analysis of the PCC were helpful in planning surgical approach-identifying and controlling the PCEV, and skeletonization of the PCC without compromising the hypoglossal nerve and anterior condylar emissary vein.

Three ipsilateral paracondylar processes with other skull base variations: case report.

Variations of the skull base can affect surgical approaches and must be considered when viewing and interpreting radiological imaging. Here, we report a unique collection of bony anatomical variations found on a single adult skull. Three bony excrescences from the occipital bone were identified in the paracondylar region. The smallest of these processes was 7 mm long and was just medial to the mastoid process of the temporal bone and posterior to the styloid process. One bony process was attached to the occipital condyle and was 12 mm in length. The longest of these processes was 17 mm long and arose from the jugular process of the occipital bone. Paracondylar processes can be symptomatic. Knowledge of the bony variations at the skull base is important to those who operate in this region or review and interpret radiological imaging.

Reappraisal of the types of hypoglossal canal: endocranial approach.

This study aims to classify the endocranial variations inside the Hypoglossal Canal (HC) and evaluate the elements of the HC region in terms of sizes, diameters, and distances to the nearby surgical landmarks. The present study was done on 18 adult human fixed cadaver heads bilaterally. The internal opening of HC was examined for the presence of dural or osseos septations in the canal and was classified into five types (Type 1-5). The dimensions of hypoglossal nerve (CN XII) and the distance of intracranial openings of HC from the jugular foramen and jugular tubercle were measured. The prevalence of endocranial HC types were determined on both sides as follows: type 1 (23.53% left, 6.25% right), type 2 (37.5% right, 5.88% left), type 3 (52.94% left, 25% right), type 4 (18.75% right, 17.65% left), type 5 (12.5% right). Understanding the endocranial HC types is crucial for neurosurgeons in the differential diagnosis of various intracranial pathologies for the posterior cranial fossa approach. Knowing the anatomical relationships between the adjacent structures and symmetrical organization of the HC according to the types is crucial in determining surgical strategies and preserving adjacent structures.

The combined transarterial and transvenous onyx embolization of dural arteriovenous fistula of hypoglossal canal via the external jugular vein and facial vein: A case report.

Dural arteriovenous fistulas of the hypoglossal canal (HCDAVFs) involving the anterior condylar confluence (ACC) and anterior condylar vein (ACV) are infrequent. Although transvenous embolization through the internal jugular vein (IJV) is the preferred treatment option for type I and II fistulas, it can be difficult if the IJV is unavailable. Here we report a rare case of HCDAVF in which the most common transvenous embolization access via IJV was not available. The patient underwent transarterial and transvenous onyx embolization. Transarterial embolization (TAE) aimed at controlling the arterial inflow and subsequently TVE was performed via the external jugular vein (EJV), the facial vein, the ophthalmic vein, the cavernous sinus, ACC, and ultimately to the fistula pouch. Complete obliteration of the HCDAVF was achieved without complications. We suggest that transvenous embolization (TVE) via the EJV and the facial vein can be effective in cases where trans-IJV is not possible.

Angulation Between the Occipital Condyle and the Hypoglossal Canal: An Anatomical Study With Application in Transcondylar Approaches and Occipital Condyle Screw Placement.

Background A detailed understanding of the relationship between the occipital condyle (OC) and the deeper-lying hypoglossal canal (HC) is necessary for surgeons who place screws into the OC or drill through or around the HC. Therefore, this anatomical study was performed. Methodology A total of 30 skulls (60 sides) underwent an analysis of the angle formed between the long axis of the OC and the HC, i.e., the OC/HC angle. Additionally, the lengths and widths of the OCs and foramen magnum (FM) of each skull were measured using a micrometer. Statistical analyses were performed between the left and right sides, and a Pearson's correlation coefficient was calculated between OC/HC angles and the sizes of the OCs and FM of the skulls. Results The OC/HC angle for the left and right sides ranged from 30 to 56 degrees (mean 46 degrees). The width of the OCs ranged from 9 to 18 mm (mean 13 mm). The length of the OCs was 18 to 31 mm (mean 24 mm). The mean length and width of the FM were 36 mm and 30 mm, respectively. There was no statistically significant difference between the OC/HC angle comparing left and right sides or male or female specimens. Additionally, no statistically significant differences were found between septated and non-septated HC. Pearson's correlation coefficient for left and right OC/HC angles and left and right OC lengths was r = 0.4056 and r = 0.2378, respectively. Pearson's correlation coefficient for left and right OC/HC angles and left and right OC width was r = 0.3035 and r = 0.3530, respectively. Pearson's correlation coefficient for left and right OC/HC angles and the width of the FM was r = 0.2178 and r = 0.2048, respectively. Pearson's correlation coefficient for left and right OC/HC angles and the length of the FM was r = 0.3319 and r = 0.2683, respectively. Conclusions The OC/HC angle as measured here was relatively consistent with no statistically significant differences between sides. We did not find a strong correlation between the width or length of the OC or the width or length of the FM and the OC/HC angles. Therefore, based on our study, surgeons can expect that this angle will range between 30 and 56 degrees (mean 46 degrees). Such knowledge might decrease patient morbidity following invasive procedures involving the OC.

Transvenous coil embolization of hypoglossal canal dural arteriovenous fistula using detachable coils: A case report.

The hypoglossal canal (HC) is an unusual location of the posterior fossa dural arteriovenous fistula (AVF), which usually occurs in the transverse or sigmoid sinus. Herein, we report a case of HC dural AVF successfully treated with transvenous coil embolization using detachable coils in a 68-year-old woman who presented with headache and left pulsatile tinnitus for 2 months. Brain magnetic resonance imaging (MRI) and cerebral angiography revealed left HC dural AVF. The pulsatile bruit disappeared immediately after the procedure. Follow-up MRI showed complete disappearance of the fistula. Precise localization of the fistula through careful consideration of the anatomy and transvenous coil embolization using a detachable coil can facilitate the treatment for HC dural AVF.

Simplifying the Surgical Classification and Approach to the Posterolateral Skull Base and Jugular Foramen Using Anatomical Triangles.

Introduction Lesions of the jugular foramen (JF) and postero-lateral skull base are difficult to expose and exhibit complex neurovascular relationships. Given their rarity and the increasing use of radiosurgery, neurosurgeons are becoming less experienced with their surgical management. Anatomical factors are crucial in designing the approach to achieve a maximal safe resection. Methods and methods Six cadaveric heads (12 sides) were dissected via combined post-auricular infralabyrinthine and distal transcervical approach with additional anterior transstyloid and posterior far lateral exposures. Contiguous surgical triangles were measured, and contents were analyzed. Thirty-one patients (32 lesions) were treated surgically between 2000 and 2016 through different variations of the retro-auricular distal cervical transtemporal approaches. Results We anatomically reviewed the carotid, stylodigastric, jugular, condylar, suboccipital, deep condylar, mastoid, suprajugular, suprahypoglossal (infrajugular), and infrahypoglossal triangles. Tumors included glomus jugulare, lower cranial nerve schwannomas or neurofibromas, meningiomas, chondrosarcoma, adenocystic carcinoma, plasmacytoma of the occipitocervical joint, and a sarcoid lesion. We classified tumors into extracranial, intradural, intraosseous, and dumbbell-shaped, and analyzed the approach selection for each. Conclusion Jugular foramen and posterolateral skull base lesions can be safely resected through a retro-auricular distal cervical lateral skull base approach, which is customizable to anatomical location and tumor extension by tailoring the involved osteo-muscular triangles.