Surgical anatomy of the jugular foramen

Comparison of Endoscopic Endonasal Approach and Lateral Microsurgical Infratemporal Fossa Approach to the Jugular Foramen: An Anatomical Study

Objective The jugular foramen is one of the most challenging surgical regions in skull base surgery. With the development of endoscopic techniques, the endoscopic endonasal approach (EEA) has been undertaken to treat some lesions in this area independently or combined with open approaches. The purpose of the current study is to describe the anatomical steps and landmarks for the EEA to the jugular foramen and to compare it with the degree of exposure obtained with the lateral infratemporal fossa approach.

Materials and Methods A total of 15 osseous structures related to the jugular foramen were measured in 33 adult dry skulls. Three silicone-injected adult cadaveric heads (six sides) were dissected for EEA and three heads (six sides) were used for a lateral infratemporal fossa approach (Fisch type A). The jugular foramen was exposed, relevant landmarks were demonstrated, and the distances between relevant landmarks and the jugular foramen were obtained. High-quality pictures were obtained.

Results The jugular foramen was accessed in all dissections by using either approach. Important anatomical landmarks for EEA include internal carotid artery (ICA), petroclival fissure, inferior petrosal sinus, jugular tubercle, and hypoglossal canal. The EEA exposed the anterior and medial parts of the jugular foramen, while the lateral infratemporal fossa approach (Fisch type A) exposed the lateral and posterior parts of the jugular foramen. With EEA, dissection and transposition of the facial nerve was avoided, but the upper parapharyngeal and paraclival ICA may need to be mobilized to adequately expose the jugular foramen.

Conclusion The EEA to the jugular foramen is anatomically feasible but requires mobilization of the ICA to provide access to the anterior and medial aspects of the jugular foramen. The lateral infratemporal approach requires facial nerve transposition to provide access to the lateral and posterior parts of the jugular foramen. A deep understanding of the complex anatomy of this region is paramount for safe and effective surgery of the jugular foramen. Both techniques may be complementary considering the different regions of the jugular foramen accessed with each approach.

Endonasal access to lower cranial nerves: From foramina to upper parapharyngeal space

Lesions arising from the upper parapharyngeal space (UPPS) often involved the jugular foramen region (JFR), occasionally extending into the posterior cranial fossa. This study aims to investigate the surgical anatomy of the JFR and UPPS from the perspective of an expanded endoscopic approach (EEA), tracing the lower cranial nerves from their extracranial foramina to the UPPS. Six cadaveric specimens (12 sides) underwent a transpterygoid EEA to expose the JFR and UPPS. Distances from the medial pterygoid plate (MPP) to the internal carotid artery (ICA), hypoglossal canal (HC), and jugular tubercle (JT) were measured on anonymized Computed tomography angiography images previously obtained from 30 patients with pulsatile tinnitus. Full access to the JFR, and its medial, superior, and anterior aspects, could be adequately achieved via an EEA. Upon exiting the jugular foramen, the glossopharyngeal nerve courses posterior to the ICA, traveling inferiorly into the UPPS between ICA and IJV. The vagus nerve is in close proximity to the hypoglossal nerve traveling posterior to the ICA. The accessory nerve courses lateral to the vagus nerve, running posterior to the IJV. The minimal distances from the MPP to ICA, HC, and JT were 2.52 ± 0.34, 2.86 ± 0.36, and 3.18 ± 0.33 cm, respectively. This anatomical study strongly suggests the feasibility of using an EEA to access to the medial, superior, and anterior aspects of the jugular foramen and the adjacent UPPS.

Intraforaminal Dural Septations of the Jugular Foramen: A Cadaveric Study

OBJECTIVE

The aim of this study was to define the types, prevalences, and diameters of dural septations (DSs) on the inner surface of the jugular foramen (JF) and to describe the distances between the JF, the glossopharyngeal nerve (cranial nerve [CN] IX), vagus nerve (CN X), and accessory nerve (CN XI), the internal acoustic meatus, and nearby surgical landmarks on cadaveric heads.

METHODS

Seventeen adult (9 men and 8 women) formalin-fixed cadaveric heads were used to analyze the types and prevalence of DS bilaterally. Diameters and distances between the DS and the adjacent CNs (CN IX-XI) were measured by digital microcaliper. The multiple t test (SPSS version 25) was used to analyze the comparison between both sides via diameters, numbers, distance, length, and thickness of DS.

RESULTS

The most frequent type of DS was type I (62.5%, right; 56.3%, left), followed by type II (18.8%, right; 25%, left), type III (12.5%, right; 6.3%, left), and type IV (6.3%, right; 12.5%, left). The mean diameter of the septum was 0.6-1 mm, and the mean length of the dural septa was 4.01 mm (right) and (3.83 mm) left. The difference in the length and thickness of the DS between the genders was statistically significant on both sides (P < 0.05). The DS-CN X and DS-JF distances of women were greater than those of men on the right side (P < 0.05).

CONCLUSIONS

The significant differences between dural septum types on the 2 sides of the body may indicate asymmetric location or a variant emerging site of CNs in the same individual.

Multifocal cavernous hemangioma of the jugular foramen: a rare skull base vascular malformation

Jugular foramen cavernous hemangiomas are extremely rare vascular malformations, and, to the best of the authors' knowledge, their occurrence as multifocal lesions involving both intra- and extracranial compartments has never been reported before. Here, the authors describe the case of a 60-year-old woman with a complex multifocal jugular foramen cavernous hemangioma. The patient presented with signs and symptoms concerning for jugular foramen syndrome, as well as a right neck mass. Surgical extirpation of the lesion was achieved by a multidisciplinary team via a right infratemporal fossa approach (Fisch type A) with concurrent high neck dissection and a closure buttressed with an autologous fat graft and a temporoparietal fascial flap. Although rare, cavernous hemangiomas should be included in the differential diagnosis of jugular foramen masses.

Papillary meningioma of the jugular foramen: A case report

Papillary meningioma (PM) is a rare histological variant of intracranial meningioma, which displays an aggressive behavior and its management is difficult. The present study reported the case of a 21-year-old male patient, who presented with headaches and dizziness. Upon neurological examination, left hypoglossal nerve palsy and left cerebellar signs were observed. Computed tomography and magnetic resonance imaging scans of the brain revealed a high-density mass in the left jugular foramen area. Following an uneventful complete surgical resection of the tumor, a definitive diagnosis of Grade III PM was determined based on the histopathological findings, according to the World Health Organization classification. CT scanning one day after surgery confirmed that the tumor had been completely resected, and after four years of follow-up, no evidence of transformation or recurrence was observed.

[Management of bone-invasive en-plaque petrosal meningiomas. Removal using tailored petrosectomy]

BACKGROUND AND PURPOSE

The invasion of bone responsible for hyperostosis is a typical phenomenon associated with en-plaque meningiomas. Although the sphenoid wing and spheno-orbital region are most frequently affected, petrosal involvement is rare and its surgical treatment difficult. Hyperostosis is caused by bone invasion, is responsible for the clinical signs, and prompts the surgeon to use an à la carte drilling that has to be evaluated preoperatively and carried out depending on tumor extension and the treatment goals.

METHODS

We report two cases of invasive and evolving en-plaque petrosal meningiomas. Hyperostosis, bony modifications, and intracranial portion of the lesion were responsible for cophosis, facial palsy, trigeminal neuralgia, dysphonia, and laryngeal palsy in one case, and were responsible for hearing loss and facial palsy in the other case.

RESULTS

In both cases, the à la carte petrosectomy allowed us to achieve total removal of the lesion. In one case, we used a trans- and infralabyrinthine transjugular approach (to control the extension of the lesion in the jugular foramen, within the sinusojugular axis, and in the internal auditory canal), associated with an anterior petrosectomy (to control the invaded petrous apex, Meckel's cave, and a middle cranial fossa extension). In the other case, we used a retro- and infralabyrinthine transsigmoid transtentorial approach to control the venous axis, the posterior fossa dura, and the tentorium. Total removal of the tumor including bone invasion was achieved in both cases. Neurological deficits improved or remain unchanged. Transient postoperative facial palsy recovered in two months.

CONCLUSIONS

An à la carte petrosectomy performed by a surgical team with great expertise in the field of petrous bone anatomy and segmentation should lead to total removal including exposure of the dural tail and intracranial portion of the tumor, while preserving all cranial nerve functions.

The jugular foramen: imaging strategy and detailed anatomy at 3T

BACKGROUND AND PURPOSE

The purpose of this study was to assess how well the anatomy of the jugular foramen (JF) could be displayed by 3T MR imaging by using a 3D contrast-enhanced fast imaging employing steady-state acquisition sequence (CE-FIESTA) and a 3D contrast-enhanced MR angiographic sequence (CE-MRA).

MATERIALS AND METHODS

Twenty-five patients free of skull base lesions were imaged on a 3T MR imaging scanner using CE-FIESTA and CE-MRA. Two readers analyzed the images in collaboration, with the following objectives: 1) to score the success with which these sequences depicted the glossopharyngeal (CNIX) and vagus (CNX) nerves, their ganglia, and the spinal root of the accessory nerve (spCNXI) within the JF, and 2) to determine the value of anatomic landmarks for the in vivo identification of these structures.

RESULTS

CE-FIESTA and CE-MRA displayed CNIX in 90% and 100% of cases, respectively, CNX in 94% and 100%, and spCNXI in 51% and 0% of cases. The superior ganglion of CNIX was discernible in 89.8% and 87.8%; the inferior ganglion of CNIX, in 73% and 100%; and the superior ganglion of CNX, in 98% and 100% of cases. Landmarks useful for identifying these structures were the inferior petrosal sinus and the external opening of the cochlear aqueduct.

CONCLUSIONS

This study protocol is excellent for displaying the complex anatomy of the JF and related structures. It is expected to aid in detecting small pathologies affecting the JF and in planning the best surgical approach to lesions affecting the JF.