Jugular Foramen Research Articles

Metastatic Malignant Glomus Jugulare Tumor: A Rare Case Report with Clinical Manifestations and Treatment Approach.

BACKGROUND Paragangliomas are neuroendocrine neoplasms derived from paraganglia of the sympathetic and parasympathetic nervous systems. Parasympathetic ganglia-derived tumors, also called non-chromaffin, are located almost exclusively in the neck and skull base and are usually non-secretory and inactive. A case of malignant glomus jugulare with a metastatic cervical lymph node is described here. CASE REPORT A 24-year-old woman was referred to an otolaryngology clinic for concern of voice change for 1 month, which was associated with right progressive hearing loss, pulsating tinnitus, and right facial weakness. A clinical examination revealed a reddish mass in the right ear behind an intact tympanic membrane with right facial weakness of House-Brackmann grade VI. A bedside flexible nasopharyngoscopy revealed an immobile right vocal fold. A computed tomography scan of the brain revealed a destructive lesion within the right jugular foramen. The patient underwent embolization followed by glomus tumor resection via infra-temporal fossa with Fisch type A approach. Pathology revealed that the tumor was an infiltrative epithelioid tumor with a spindle and nesting pattern separated by fibrovascular stroma. The submitted lateral neck lymph node revealed a metastatic tumor. CONCLUSIONS Glomus jugulare tumors are uncommon paragangliomas, and malignant behavior with metastasis is extremely rare. Metastatic tumors are often associated with facial and vagal nerves palsy. There are no histological features that distinguish malignant glomus jugulare tumors. Malignant neoplasms are characterized by the presence of metastases. Tumors of the glomus jugulare that are malignant are treated with surgery, radiotherapy, or both. However, our search of the literature revealed no clear guidelines, given the scarcity of cases. Moreover, the presence of metastasis increases the risk of death.

Detailed Anatomy of Bridging Veins Around the Foramen Magnum: a Multicenter Study Using Three-dimensional Angiography

Background and PurposeThere has been limited literature regarding the bridging veins (BVs) of the medulla oblongata around the foramen magnum (FM). The present study aims to analyze the normal angioarchitecture of the BVs around the FM using slab MIP images of three-dimensional (3D) angiography.MethodsWe collected 3D angiography data of posterior fossa veins and analyzed the BVs around the FM using slab MIP images. We analyzed the course, outlet, and number of BVs around the FM. We also examined the detection rate and mean diameter of each BV.ResultsOf 57 patients, 55 patients (96%) had any BV. The median number of BVs was two (range: 0–5). The BVs originate from the perimedullary veins and run anterolaterally to join the anterior condylar vein (ACV), inferior petrosal sinus, sigmoid sinus, or jugular bulb, inferolaterally to join the suboccipital cavernous sinus (SCS), laterally or posterolaterally to join the marginal sinus (MS), and posteriorly to join the MS or occipital sinus. We classified BVs into five subtypes according to the draining location: ACV, jugular foramen (JF), MS, SCS, and cerebellomedullary cistern (CMC). ACV, JF, MS, SCS, and CMC BVs were detected in 11 (19%), 18 (32%), 32 (56%), 20 (35%), and 16 (28%) patients, respectively. The mean diameter of the BVs other than CMC was 0.6 mm, and that of CMC BV was 0.8 mm.ConclusionUsing venous data from 3D angiography, we detected FM BVs in most cases, and the BVs were connected in various directions.

Management of a Complex Case of a Recurrent Paraganglioma.

Paragangliomas are rare, slow-growing, hypervascular, catecholamine-secreting neuroendocrine tumors arising from the paraganglia. Paragangliomas are rarely found in the head and neck and are typically benign, presenting as a painless, slow-growing mass. Surgical extirpation in combination with long-term surveillance has been long regarded as the standard of care; however, the advances in imaging, radiation therapy, and embolization techniques have improved diagnostic and therapeutic modalities. We present a case of an 87-year-old female who had previously undergone resection of a paraganglioma in 1998, with no evidence of disease in 2002. Eighteen years later, the patient presented to the clinic with otogenic complaints. Imaging showed an expansive mass from the jugular foramen with bone destruction and opacification within the ear canal. The patient opted for observation. The patient eventually presented to the emergency room with neurologic manifestations. Imaging showed a cerebellar abscess prompting emergency drainage. Intraoperative cultures grew Prevotella loescheii and S. intermedius, and the patient was started on 6 weeks of IV antibiotic therapy. Debulking of the paraganglioma was performed followed several months by mastoid and ear canal obliteration; however, the patient experienced complications, including dehiscence of the external auditory canal and Clostridium difficile infection. The patient was eventually treated successfully, marked by a reduction in complaints, a return to baseline activities, and imaging showing no increase in tumor size.

Neurologic deficits and surgical treatment in a horse affected with internal carotid artery tortuous elongation

SummaryA 2‐year‐old Warmblood gelding was presented with a history of bilateral feed material coming from the nostrils secondary to dysphagia, coughing and impairment of physical development, since purchase at 6 months of age. Endoscopy of the right guttural pouch was unremarkable; however, in the left guttural pouch, a distended (aneurysm), pulsating, tortuous elongated internal carotid artery (ICA) was observed. Computed tomography revealed that in the dorsal aspect of the medial compartment of the left guttural pouch adjacent to the jugular foramen, the ICA turned anti‐clockwise creating a small loop of 1 cm diameter. This loop had a faint linear, soft tissue attenuating connection to the caudodorsal wall of the guttural pouch and was slightly larger in diameter compared to the right ICA. A malformation of the left ICA was diagnosed, most likely congenital. A secondary compression and neuropathy of one or multiple nerves of the associated lower cranial nerves in the neurovascular plica (IX, X) was suspected explaining the clinical signs of dysphagia. The slightly larger diameter of the left ICA could represent congestion of the vessel or an early aneurysm formation. Based on these findings, endovascular balloon occlusion (nondetachable balloon) of the left ICA was performed to relief the compression on the affected nerves. The occlusion of the ICA resolved the clinical signs within 7 weeks after surgery.

Approaching Intradural Lesions of the Anterior Foramen Magnum and Craniocervical Junction: Anatomical Comparison of the Open Posterolateral and Anterior Extended Endonasal Endoscopic Approaches

Lesions of the foramen magnum (FM) and craniocervical junction area are traditionally managed surgically through anterior, anterolateral, and posterolateral skull-base approaches. This anatomical study aimed to compare the usefulness of a modified extended endoscopic approach, the so-called far-medial endonasal approach (FMEA), versus the traditional posterolateral far-lateral approach (FLA). Ten fixed silicon-injected heads specimens were used in the Skull Base ENT-Neurosurgery Laboratory of the University Hospital of Strasbourg, France. A total of 20 FLAs and 10 FMEAs were realized. A high-resolution computed tomography scan was performed for quantitative analysis of the different approaches. The analysis aimed to estimate the extent of surgical exposure and freedom of movement (maneuverability) through the operating channel using a polygonal surface model to obtain a morphometric estimation of the area of interest (surface and volume) on postdissection computed tomography scans using Slicer 3D software. FMEA allows for a more direct route to the anterior FM, with wider brainstem exposure compared with the FLA and an excellent visualization of all anterior midline structures. The limitations of the FMEA include the deep and narrow surgical corridor and difficulty in reaching lesions located laterally over the jugular foramen and hypoglossal canal. The FMEA and FLA are both effective surgical routes to reach FM and craniocervical junction lesions. Modern skull base surgeons should have a good command of both because they appear complementary. This anatomical study provides the tools for comprehensive preoperative evaluations and selection of the most appropriate surgical approach.

Transmastoid/Infralabyrinthine Approach to the Jugular Foramen: 2-Dimensional Operative Video.

This approach is intended for tumors centered in the jugular foramen with extensions between intracranial and extracranial spaces, possible spread to the middle ear, and variable bony destruction. 1,2. Jugular foramen paragangliomas are complex lesions that usually invade and fill related venous structures. They present complex relationships with skull base neurovascular structures as internal carotid artery, lower cranial nerves (CNs), middle ear, and mastoid segment of facial nerve. In this way, it is essential to perform an adequate preoperative vascular study to evaluate sinus patency and the tumor blood supply, besides a computed tomography scan to depict bone erosion. Mastoidectomy through an infralabyrinthine route up to open the lateral border of jugular foramen, allowing exposure from the sigmoid sinus to internal jugular vein. Skeletonization of facial canal without exposure of facial nerve is performed and opening of facial recess to give access to the middle ear in way of a fallopian bridge technique. 2-10. If there is preoperative preservation of lower CN function, it is important to not remove the anteromedial wall of the internal jugular vein and jugular bulb. In addition, facial nerve should be exposed just in case of preoperative facial palsy to decompress or reconstruct the nerve. Variations are related mainly with temporal bone drilling depending on the extensions of the lesion, its source of blood supply, and preoperative preservation of CN function.Informed consent was obtained from the patient for the procedure and publication of his image.Anatomy images were used with permission from:• Ceccato GHW, Candido DNC, and Borba LAB. Infratemporal fossa approach to the jugular foramen. In: Borba LAB and de Oliveira JG. Microsurgical and Endoscopic Approaches to the Skull Base. Thieme Medical Publishers. 2021.• Ceccato GHW, Candido DNC, de Oliveira JG, and Borba LAB. Microsurgical Anatomy of the Jugular Foramen. In: Borba LAB and de Oliveira JG. Microsurgical and Endoscopic Approaches to the Skull Base. Thieme Medical Publishers. 2021.

Endoscopic Endonasal Transpterygoid Approach: Technical Lessons.

The endoscopic endonasal transpterygoid approach (EETPA) provides direct access to the petrous apex, lateral clivus, inferior cavernous sinus compartment, jugular foramen, and infratemporal fossa. 1,2 In the coronal plane, it provides exposure far beyond a traditional sphenoidotomy. The pterygoid process of the sphenoid bone forms the junction between the body and greater sphenoid wing before bifurcating because it descends into medial and lateral plates. The key to this exposure lies in the region's bony foramina: the palatovaginal canal, vidian canal, and foramen rotundum. 3. After performing a maxillary antrostomy, stepwise exposure of these foramina leads to the pterygopalatine fossa. The sphenopalatine artery is cauterized as it becomes the posterior septal artery at the sphenopalatine foramen, and the maxillary sinus' posterior wall is opened to expose the pterygopalatine fossa. After mobilizing and retracting the contents of the pterygopalatine fossa, the pterygoid process is removed, improving access in the coronal plane. 4. Vidian neurectomy causes decreased or absent lacrimation. Injury to the maxillary nerve or its branches results in facial, palatal, or odontogenic anesthesia or neuralgia. In addition, the EEPTA precludes the ability to raise an ipsilateral nasal septal flap, making it crucial to plan reconstruction preoperatively. 4,5. There are 5 variants of the EEPTA: extended pterygopalatine fossa, lateral recess of the sphenoid sinus, petrous apex, infratemporal fossa and petrous carotid artery, and middle and posterior skull base. 5The patient consented to the procedure.Images in the video used with permission as follows: images at 0:33 and 1:15 reused from Bozkurt et al, 3 © Georg Thieme Verlag KG; image at 0:39 from Prosser et al, 5 © John Wiley and Sons; images at 0:54, 9:03, and 9:38 from Kasemsiri et al, 1 © John Wiley and Sons; images at 1:07 and 9:44 from Falcon et al, 2 © John Wiley and Sons; image at 1:15 from Sandu et al, 4 © Springer Nature.

Retrosigmoid Craniotomy and Intradural Variations: Role of Patient-Specific Preoperative Imaging to Identify Landmarks and Relevant Structures

There are several landmarks to safely identify the limits of the retrosigmoid approach and its intradural variations, however, little has been discussed about how those landmarks may vary among patients. We provided a review of patient positions, surface landmarks for the retrosigmoid craniotomy, and structures to recognize for transmeatal, suprameatal, suprajugular and transtentorial extensions. The position of the dural sinuses in relation with the zygomatic-inion line, and digastric notch line is readily identified on MRI. For transmeatal drilling, the position of the semicircular canals, vestibular aqueduct and jugular bulb is best evaluated on CT. For suprameatal drilling, the labyrinth and the position and integrity of the carotid canal are relevant to plan the anterior extension of the approach. For transtentorial extension, it is desirable to identify incisural structures. For suprajugular drilling, the position of the jugular bulb, invasion of venous structures, and integrity of the roof of the jugular foramen must be checked preoperatively. The retrosigmoid approach is the workhorse of posterior skull base surgery. By recognizing patient-specific variations in known landmarks, the approach may be tailored prevent complications.

Endoscopic Endonasal Approach to the Ventral Petroclival Fissure: Anatomical Findings and Surgical Techniques.

Objective The endoscopic endonasal approach has emerged as an excellent option for the treatment of lesions involving the petroclival fissure (PCF). Here, we investigate the surgical anatomy of the ventral PCF and its application in endoscopic endonasal surgery. Methods Sixteen head specimens were used to investigate the anatomical features of PCF and relevant technical nuances in translacerum, extreme medial, and contralateral transmaxillary (CTM) approaches. Two representative endoscopic endonasal surgeries involving the PCF were selected to illustrate the clinical application. Results From the endoscopic endonasal view, the ventral PCF is presented as a lazy L sign, which is divided into two distinct segments: (1) upper (or petrosphenoidal) segment, which extends vertically from the foramen lacerum inferiorly to the junction of the petrosal process of sphenoid bone and petrous apex superiorly, and (2) lower (or petroclival) segment, which extends inferolaterally from the foramen lacerum to the ventral jugular foramen. Approaching both segments of the ventral PCF first requires full exposure of the foramen lacerum, followed either by exposure of the anterior wall of cavernous sinus and paraclival internal carotid artery for upper segment access, or transection of pterygosphenoidal fissure and Eustachian tube mobilization for lower segment access. Combined with a CTM approach, the lateral extension of the surgical access can be improved for both upper and lower segment PCF approaches. Conclusion This study provides a detailed investigation of the microsurgical anatomy of the ventral part of PCF, relevant surgical approaches, and technical nuances that may facilitate its safe exposure intraoperatively.

Differential diagnosis and surgical management in chondrosarcoma of the jugular foramen

Objective: To explore the diagnosis, surgical management and outcome of jugular foramen chondrosarcoma (CSA). Methods: Fifteen patients with jugular foramen CSA hospitalized in the Department of Otorhinolaryngology Head and Neck Surgery of Chinese PLA General Hospital from December 2002 to February 2020 were retrospectively collected,of whom 2 were male and 13 were female, aging from 22 to 61 years old. The clinical symptoms and signs, imaging features, differential diagnosis, surgical approaches, function of facial nerve and cranial nerves IX to XII, and surgical outcomes were analyzed. Results: Patients with jugular foramen CSA mainly presented with facial paralysis, hearing loss, hoarseness, cough, tinnitus and local mass. Computed tomography (CT) and magnetic resonance (MR) could provide important information for diagnosis. CT showed irregular destruction on bone margin of the jugular foramen. MR demonstrated iso or hypointense on T1WI, hyperintense on T2WI and heterogeneous contrast-enhancement. Surgical approaches were chosen upon the sizes and scopes of the tumors. Inferior temporal fossa A approach was adopted in 12 cases, inferior temporal fossa B approach in 2 cases and mastoid combined parotid approach in 1 case. Five patients with facial nerve involved received great auricular nerve graft. The House Brackmann (H-B) grading scale was used to evaluate the facial nerve function. Preoperative facial nerve function ranked grade Ⅴ in 4 cases and grade Ⅵ in 1 case. Postoperative facial nerve function improved to grade Ⅲ in 2 cases and grade Ⅵ in 3 cases. Five patients presented with cranial nerves Ⅸ and Ⅹ palsies. Hoarseness and cough of 2 cases improved after operation, while the other 3 cases did not. All the patients were diagnosed CSA by histopathology and immunohistochemistry, with immunohistochemical staining showing vimentin and S-100 positive, but cytokeratin negative in tumor cells. All patients survived during 28 to 234 months' follow-up. Two patients suffered from tumor recurrence 7 years after surgery and received revision surgery. No complications such as cerebrospinal fluid leakage and intracranial infection occurred after operation. Conclusions: Jugular foramen CSA lacks characteristic symptoms or signs. Imaging is helpful to differential diagnosis. Surgery is the primary treatment of jugular foramen CSA. Patients with facial paralysis should receive surgery in time as to restore the facial nerve. Long-term follow-up is necessary after surgery in case of recurrence.

Visualising and semi-quantitatively measuring brain fluid pathways, including meningeal lymphatics, in humans using widely available MRI techniques

Brain fluid dynamics remains poorly understood with central issues unresolved. In this study, we first review the literature regarding points of controversy, then pilot study if conventional MRI techniques can assess brain fluid outflow pathways and explore potential associations with small vessel disease (SVD). We assessed 19 subjects participating in the Mild Stroke Study 3 who had FLAIR imaging before and 20–30 minutes after intravenous Gadolinium (Gd)-based contrast. Signal intensity (SI) change was assessed semi-quantitatively by placing regions of interest, and qualitatively by a visual scoring system, along dorsal and basal fluid outflow routes. Following i.v. Gd, SI increased substantially along the anterior, middle, and posterior superior sagittal sinus (SSS) (82%, 104%, and 119%, respectively), at basal areas (cribriform plate, 67%; jugular foramina, 72%), and in narrow channels surrounding superficial cortical veins separated from surrounding cerebrospinal fluid (CSF) (96%) (all p < 0.001). The SI increase was associated with higher intraparenchymal perivascular spaces (PVS) scores (Std. Beta 0.71, p = 0.01). Our findings suggests that interstitial fluid drainage is visible on conventional MRI and drains from brain parenchyma via cortical perivenous spaces to dural meningeal lymphatics along the SSS remaining separate from the CSF. An association with parenchymal PVS requires further research, now feasible in humans.

The Anterolateral Approach, Revisited for Benign Jugular Foramen Tumors With Predominant Extracranial Extension: Microsurgical Anatomy and Case Series (SevEN-012).

The anterolateral approach (ALA) enables access to the mid and lower clivus, jugular foramen (JF), craniocervical junction, and cervical spine with added anterior and lateral exposure than the extreme lateral and endoscopic endonasal approach, respectively. We describe the microsurgical anatomy of ALA with cadaveric specimens and report our clinical experience for benign JF tumors with predominant extracranial extension. A stepwise and detailed microsurgical neurovascular anatomy of ALA was explored with cadaveric specimens. Then, the clinical results of 7 consecutive patients who underwent ALA for benign JF tumors with predominant extracranial extension were analyzed. A hockey stick skin incision is made along the superior nuchal line to the anterior edge of the sternocleidomastoid muscle (SCM). ALA involves layer-by-layer muscle dissection of SCM, splenius capitis, digastric, longissimus capitis, and superior oblique muscles. The accessory nerve runs beneath SCM and is found at the posterior edge of the digastric muscle. The internal jugular vein (IJV) is lateral to and at the level of the accessory nerve. The occipital artery passes over the longissimus capitis muscle and IJV and into the external carotid artery, which is lateral and superficial to IJV. The internal carotid artery (ICA) is more medial and deeper than external carotid artery and is in the carotid sheath with the vagus nerve and IJV. The hypoglossal and vagus nerves run along the lateral and medial side of ICA, respectively. Prehigh cervical carotid, prejugular, and retrojugular surgical corridors allow deep and extracranial access around JF. In the case series, gross and near-total resections were achieved in 6 (85.7%) patients without newly developed cranial nerve deficits. ALA is a traditional and invaluable neurosurgical approach for benign JF tumors with predominant extracranial extension. The anatomic knowledge of ALA increases competency in adding anterior and lateral exposure of extracranial JF.

PO-02-164 VALUE OF CARDIONEUROABLATION WITH VAGAL DENERVATION CONFIRMED BY VAGUS NERVE STIMULATION ON PULMONARY VEIN ISOLATION FOR ATRIAL FIBRILLATION CATHETER ABLATION

Despite good results, Atrial fibrillation(AF) ablation shows a relatively high recurrence rate. Therefore, we sought to verify whether endocardial denervation by cardioneuroablation(CNA) can change the AF recurrence post-pulmonary vein isolation(PVI). To compare the long-term AF recurrence post-PVI versus PVI plus vagal denervation (PVI+CNA) by CNA with vagal denervation confirmation by extracardiac vagal stimulation(ECVS). Case-control study of 127 patients, 104(81.9%) males, 53.7±12 years-old, with paroxysmal 71(55.9%) or persistent 56(44.1%) symptomatic AF, refractory to medications without cardiopathy, LA=39.8±6.8, EF=0.66±0.55. Two equivalent groups were established: PVI alone (55 cases) and PVI+CNA (72 cases). The ECVS was performed by intravenous catheter, near the jugular foramen with 50Hz/50microsec/1V/Kg/up to 70V. Endocardial CNA was biatrial over the four main ganglionated plexus and in the AF-Nests regions tagged by fractionation software. The endpoint of CNA was the elimination of the vagal effect induced by ECVS. PVI was achieved in all cases. ECVS effectively induced a vagal reaction in all PVI+CNA patients, and it was possible to eliminate the vagal effect in 88.9% of cases. In 11.1%, there was a slight residual vagal response. Patients were followed up to 45 months (mean FU=21.4±14.2 and 20.4 ± 14.3 months). Recurrences were 17 in the PVI group, and 4 in the PVI+CNA group: Log-Rank p<0.00, HR:5.38(1.78-16.29,p=0.003). No significant complications occurred. The addition of vagal denervation to PVI, with validation of the vagal denervation by ECVS, significantly increased the success rate of the PVI with a marked reduction in AF relapses without increasing complications.

In Reply to the Letter to Editor Regarding “Case Series and Systematic Review of Electronic Scooter Crashes and Severe Traumatic Brain Injury”

Jugular foramen schwannomas are rare. To our knowledge only a small number of series including a large number of patients have been reported. We aimed to analyse the clinical characteristics, surgical approaches, and outcome of patients undergoing treatment for jugular foramen schwannomas via a retrospective analysis of departmental records. Data for 28 patients treated for jugular foramen schwannomas in the Department of Neurosurgery at our tertiary level referral institution between January 2001 and December 2010 were analysed. Most patients were in the fourth decade of life, with the duration of symptoms ranging from 1 month to 13 years. A skull base approach was used in every surgically treated patient. Of the 19 patients for whom radiological follow-up were available, complete tumor excision was achieved in 17 patients. Follow-up ranged from 3 months to 59 months (mean, 32 months). One patient died and three had permanent morbidity in the form of facial nerve palsy. Jugular foramen schwannomas are best treated by total surgical resection. Partial resection is appropriate for tumors with adhesions to the brainstem and in medically unfit patients. Subsequent radiosurgery can be used for small residual tumors.

From a High School Student to an Otolaryngologist—19 Years With a Jugular Foramen Meningioma

In this essay, an otolaryngologist reflects on the circular journey from patient to physician to patient again over 19 years living with a left jugular foramen meningioma.

Onyx© Embolization of Dural Arteriovenous Fistulae at the Cranio-Cervical Junction (P8-5.024)

<h3>Objective:</h3> To report two cases of CRC fistula treated successfully with endovascular embolization with Onyx©. <h3>Background:</h3> Dural arteriovenous fistula (dAVF) are rare vascular malformations; a rare subset of this group are dAVFs located at the cranio-cervical junction. Subarachnoid hemorrhage (SAH) is one of the possible neurological complications of cranio-cervical (CRC) fistula rupture. Treatment options include radiosurgery, endovascular embolization and/or open surgery. The use of liquid embolic agent is a reasonable option for endovascular treatment. <h3>Design/Methods:</h3> A single institution retrospective case report identified two case of cranio-cervical junction (CRC) fistulae that were treated successfully with Onyx© embolization. <h3>Results:</h3> Two patients were identified to have cranio-cervical junction DAVF in which one patient presented with SAH, and the 2^nd patient presented with bulbar symptoms due to rapidly worsening edema in the brainstem. Both fistulas were supplied from the vertebral artery; one at the level of Dural ring of the vertebral artery and the other at the jugular foramen level which was also supplied by ascending pharyngeal artery. Onyx© embolization was the treatment of choice in both cases. The Onyx© embolization resulted in 80% reduction of the fistula nidus in the first case, and complete occlusion of the fistula in the second and the third case. The 6 months follow-up revealed complete occlusion of both fistulas with complete neurological recovery <h3>Conclusions:</h3> This case series suggests that the treatment of CRC fistulae with Onyx© embolization is efficacious with good clinical outcomes. <b>Disclosure:</b> Dr. Gharaibeh has nothing to disclose. Dr. Al-Chalabi has nothing to disclose. Dr. Oliver has nothing to disclose. Dr. Jumaa has nothing to disclose.

Lower Four Cranial Nerves in the Management of Glomus Jugulare: Anatomical Study.

Introduction The surgical management that achieves minimal morbidity and mortality for patients with glomus and non-glomus tumors involving the jugular foramen (JF) region requires a comprehensive understanding of the complex anatomy, anatomic variability, and pathological anatomy of this region. Objective The aim of this study is to propose a rational guideline to expose and preserve the lower cranial nerves (CNs) in the lateral approach of the JF. Methods The technique utilized is the gross and microdissection of 4 fixed cadaveric heads to revise the JF's surgical anatomy and high part of the carotid sheath compared with surgical cases to understand and preserve the integrity of lower CNs. The method involves radical mastoidectomy, microdissection of the JF, facial nerve, and high neck just below the carotid canal and the JF. The CNs IX, X, XI, and XII are microscopically dissected and kept in sight up to the JF. Results This study realized well the surgical and applied anatomy of the lower CNs with relation to the facial nerve and JF. Conclusions The JF anatomy is complicated, and the key to safely operate on it and preserving the lower CNs is to find the posterior belly of the digastric muscle, to skeletonize the facial nerve, to remove the mastoid tip preserving the stylomastoid foramen, to skeletonize the sigmoid sinus and posterior fossa dura not only anterior but also posteroinferior to reach and drill the jugular tubercle.

Posterolateral Routes to the Skull Base, Craniocervical Junction, and Jugular Foramen-The Far Lateral Transcondylar Approach and Combined Transpetrosal Transcervical Approaches.

The far lateral approach provides wide surgical access to the lower third of the clivus, pontomedullary junction, and anterolateral foramen magnum and rarely requires craniovertebral fusion. The most common indications for this approach are posterior inferior cerebellar artery and vertebral arteryaneurysms, brainstem cavernous malformations, and tumors anterior to the lower pons and medulla, including meningiomas of the anterior foramen magnum, schwannomas of the lower cranial nerves, and intramedullary tumors at the craniocervical junction. We provide a stepwise description of how we perform the far lateral approach, as well as how to combine the far lateral approach with other skull base approaches, including the subtemporal transtentorial approach, for lesions involving the upper clivus; the posterior transpetrosal approach, for lesions involving the cerebellopontine angle and/or petroclival region; and/or lateral cervical approaches, for lesions involving the jugular foramen or carotid sheath regions.

Surgical anatomy of hypoglossal canal for various skull base surgeries

PurposeAnatomical 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.MethodsThe 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.ResultsThere 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).ConclusionThe 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.

Massive jugular foramen schwanoma revealed by the hypogloss paralysis

Jugular foramen schwannomas are a rare event with an estimated 200 cases reported in the literature. These tumors represent only 2.9% to 4% of all intracranial schwannomas and less than 1% of all temporal bone lesions [1,2].