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Cureus Apr 2018Cranial nerve foramina are integral exits from the confines of the skull. Despite their significance in cranial nerve pathologies, there has been no comprehensive... (Review)
Review
Cranial nerve foramina are integral exits from the confines of the skull. Despite their significance in cranial nerve pathologies, there has been no comprehensive anatomical review of these structures. Owing to the extensive nature of this topic we have divided our review into two parts; Part II, presented here, focuses on the foramina of the posterior cranial fossa and discusses each foramen's shape, orientation, size, surrounding structures, and structures that pass through it. Furthermore, by comparing foramen sizes against the cross-sectional areas of their contents, we determine the amount of free space available within each. We also review lesions that can obstruct each foramen and discuss the clinical consequences.
PubMed: 29928560
DOI: 10.7759/cureus.2500 -
Journal of Neurological Surgery. Part... Oct 2019The jugular foramen occupies a complex and deep location between the skull base and the distal-lateral-cervical region. We propose a morphometric anatomical model to...
The jugular foramen occupies a complex and deep location between the skull base and the distal-lateral-cervical region. We propose a morphometric anatomical model to deconstruct its surgical anatomy and offer various quantifiable target-guided exposures and angles-of-attack. Six cadaveric heads (12 sides) were dissected using a combined postauricular infralabyrinthine and distal transcervical approach with additional anterior transstyloid and posterior far lateral exposures. We identified anatomical landmarks and combined new and previously described contiguous triangles to expose the region; we defined the jugular and deep condylar triangles. Angles-of-attack to the jugular foramen were measured after removing the digastric muscle, styloid process, rectus capitis lateralis, and occipital condyle. Removing the digastric muscle and styloid process allowed 86.4° laterally and 85.5° anteriorly, respectively. Resecting the rectus capitis lateralis and jugular process provided the largest angle-of-attack (108.4° posteriorly). The occipital condyle can be drilled in the deep condylar triangle only adding 30.4° medially. A purely lateral approach provided a total of 280.3°. Cutting the jugular ring and mobilizing the vein can further expand the medial exposure. The microsurgical anatomy of the jugular foramen can be deconstructed using a morphometric model, permitting a surgical approach customized to the pathology of interest.
PubMed: 31534895
DOI: 10.1055/s-0038-1676512 -
AJNR. American Journal of Neuroradiology Jan 2021Dural venous sinus stenosis has been associated with idiopathic intracranial hypertension and isolated venous pulsatile tinnitus. However, the utility of characterizing...
BACKGROUND AND PURPOSE
Dural venous sinus stenosis has been associated with idiopathic intracranial hypertension and isolated venous pulsatile tinnitus. However, the utility of characterizing stenosis as intrinsic or extrinsic remains indeterminate. The aim of this retrospective study was to review preprocedural imaging of patients with symptomatic idiopathic intracranial hypertension and pulsatile tinnitus, classify the stenosis, and assess a trend between stenosis type and clinical presentation while reviewing the frequencies of other frequently seen imaging findings in these conditions.
MATERIALS AND METHODS
MRVs of 115 patients with idiopathic intracranial hypertension and 43 patients with pulsatile tinnitus before venous sinus stent placement were reviewed. Parameters recorded included the following: intrinsic or extrinsic stenosis, prominent emissary veins, optic nerve tortuosity, cephalocele, sella appearance, poststenotic fusiform enlargement versus saccular venous aneurysm, and internal jugular bulb diverticula. χ cross-tabulation statistics were calculated and recorded for all data.
RESULTS
Most patients with idiopathic intracranial hypertension (75 of 115 sinuses, 65%) had extrinsic stenosis, and most patients with pulsatile tinnitus (37 of 45 sinuses, 82%) had intrinsic stenosis. Marked optic nerve tortuosity was more common in idiopathic intracranial hypertension. Cephaloceles were rare in both cohorts, with an increased trend toward the presence in idiopathic intracranial hypertension. Empty sellas were more common in idiopathic intracranial hypertension. Cerebellar tonsils were similarly located at the foramen magnum level in both cohorts. Saccular venous aneurysms were more common in pulsatile tinnitus. Internal jugular bulb diverticula were similarly common in both cohorts.
CONCLUSIONS
In this cohort, most patients with idiopathic intracranial hypertension had extrinsic stenosis, and most patients with pulsatile tinnitus had intrinsic stenosis. Awareness and reporting of these subtypes may reduce the underrecognition of potential contributory stenoses in a given patient's idiopathic intracranial hypertension or pulsatile tinnitus.
Topics: Adult; Aged; Cohort Studies; Constriction, Pathologic; Cranial Sinuses; Female; Humans; Male; Middle Aged; Pseudotumor Cerebri; Retrospective Studies; Tinnitus
PubMed: 33414231
DOI: 10.3174/ajnr.A6890 -
Surgical Neurology International 2021Jugular foramen paragangliomas (JFP) treatment represents a challenge for surgeons due to its close relationship with facial nerve (FN), lower cranial nerves (LCN), and...
BACKGROUND
Jugular foramen paragangliomas (JFP) treatment represents a challenge for surgeons due to its close relationship with facial nerve (FN), lower cranial nerves (LCN), and internal carotid artery. Due to its hypervascularization, preoperative tumor embolization has been indicated.
METHODS
Retrospective analysis of the clinical evolution of 26 patients with JFP class C/D previously embolized treated through infratemporal/cervical access without FN transposition.
RESULTS
Total and subtotal resections were 50% each, regrowth/recurrence were 25%, and 23%, respectively, and mortality was 3.9%. Postoperatively, 68.4% of patients had FN House and Brackmann (HB) Grades I/II. New FN deficits were 15.4% post embolization and 30.7% postoperatively. Previous FN deficits worsened in 46.1%. Tumor involved the FN in 30.8% and in 62.5% of them these nerves were resected and grafted (60% of them had HB III). Lateral fall, ear murmur, and vertigo improved in all patients. Tinnitus improved in 77.8% and one patient developed tinnitus after surgery. Hearing loss did not improve, eight partial hearing loss remained unchanged and four worsened. New postoperative LCN deficits were 64.3%. Postoperative KPS between 80 and 100 dropped 8.3%. Two patients with secretory paragangliomas with arterial hypertension difficult to control had better postoperative blood pressure control.
CONCLUSION
Although still with significant morbidity due to FN and LCN injuries, the treatment of patients with JFP Fisch C/D has good long-term results. Surgical techniques without FN transposition have less intraoperative nerve damage, lower rates of total resection, and higher recurrence. Preoperative embolization of JFP reduces the intraoperative blood loss but can cause FN deficit.
PubMed: 34754532
DOI: 10.25259/SNI_651_2021 -
Journal of Neurological Surgery. Part... Aug 2022Endolymphatic sac tumors (ELSTs) are rare and indolent tumors that arise from the endolymphatic sac in the posterior petrous ridge. We present a video case report...
Endolymphatic sac tumors (ELSTs) are rare and indolent tumors that arise from the endolymphatic sac in the posterior petrous ridge. We present a video case report illustrating the use of a transotic approach for resection of an expansile ELST. A 25-year-old male presented with a multiyear history of worsening left-sided hearing loss, vertigo, and headaches. Otoscopy revealed a red mass behind an intact tympanic membrane. Computed tomography revealed a large, locally aggressive mass centered in the posterior petrous temporal bone. Magnetic resonance imaging demonstrated a heterogeneously enhancing 2.4 × 3.1 × 2.4 cm tumor that exerted mass effect on the cerebellar surface with extension into the jugular foramen, tympanic cavity, internal auditory canal, and cistern of the cerebellopontine angle. A transotic approach was planned to obtain the necessary generous exposure. Preoperative angiography revealed arterial supply via the ascending pharyngeal and tumor embolization with Onyx was performed. Surgical resection began with a blind-sac closure created from the external auditory canal. The tympanic membrane and malleus were removed and the incustapedial joint was transected. A subtotal petrosectomy was performed for partial tumor exposure. The facial canal and sigmoid sinus were carefully skeletonized and a labrynthectomy was performed. The tumor was resected using a combination of bipolar cautery and blunt and sharp dissection. For closure, an abdominal fat graft was secured with overlying resorbable mesh followed by sequential closure of all skin layers. Histopathologic analysis revealed an ELST. The transotic approach offers wide exposure and facilitates large, complex tumor removal. The link to the video can be found at https://youtu.be/YvhyN8iVi44 .
PubMed: 36474718
DOI: 10.1055/s-0042-1757617 -
Journal of Neurosurgery. Spine Nov 2012The pathogenesis of syringomyelia in patients with an associated spinal lesion is incompletely understood. The authors hypothesized that in primary spinal syringomyelia,...
OBJECT
The pathogenesis of syringomyelia in patients with an associated spinal lesion is incompletely understood. The authors hypothesized that in primary spinal syringomyelia, a subarachnoid block effectively shortens the length of the spinal subarachnoid space (SAS), reducing compliance and the ability of the spinal theca to dampen the subarachnoid CSF pressure waves produced by brain expansion during cardiac systole. This creates exaggerated spinal subarachnoid pressure waves during every heartbeat that act on the spinal cord above the block to drive CSF into the spinal cord and create a syrinx. After a syrinx is formed, enlarged subarachnoid pressure waves compress the external surface of the spinal cord, propel the syrinx fluid, and promote syrinx progression.
METHODS
To elucidate the pathophysiology, the authors prospectively studied 36 adult patients with spinal lesions obstructing the spinal SAS. Testing before surgery included clinical examination; evaluation of anatomy on T1-weighted MRI; measurement of lumbar and cervical subarachnoid mean and pulse pressures at rest, during Valsalva maneuver, during jugular compression, and after removal of CSF (CSF compliance measurement); and evaluation with CT myelography. During surgery, pressure measurements from the SAS above the level of the lesion and the lumbar intrathecal space below the lesion were obtained, and cardiac-gated ultrasonography was performed. One week after surgery, CT myelography was repeated. Three months after surgery, clinical examination, T1-weighted MRI, and CSF pressure recordings (cervical and lumbar) were repeated. Clinical examination and MRI studies were repeated annually thereafter. Findings in patients were compared with those obtained in a group of 18 healthy individuals who had already undergone T1-weighted MRI, cine MRI, and cervical and lumbar subarachnoid pressure testing.
RESULTS
In syringomyelia patients compared with healthy volunteers, cervical subarachnoid pulse pressure was increased (2.7 ± 1.2 vs 1.6 ± 0.6 mm Hg, respectively; p = 0.004), pressure transmission to the thecal sac below the block was reduced, and spinal CSF compliance was decreased. Intraoperative ultrasonography confirmed that pulse pressure waves compressed the outer surface of the spinal cord superior to regions of obstruction of the subarachnoid space.
CONCLUSIONS
These findings are consistent with the theory that a spinal subarachnoid block increases spinal subarachnoid pulse pressure above the block, producing a pressure differential across the obstructed segment of the SAS, which results in syrinx formation and progression. These findings are similar to the results of the authors' previous studies that examined the pathophysiology of syringomyelia associated with obstruction of the SAS at the foramen magnum in the Chiari Type I malformation and indicate that a common mechanism, rather than different, separate mechanisms, underlies syrinx formation in these two entities. Clinical trial registration no.: NCT00011245.
Topics: Adult; Arnold-Chiari Malformation; Cerebrospinal Fluid Pressure; Diagnostic Imaging; Disease Progression; Female; Humans; Male; Middle Aged; Prospective Studies; Subarachnoid Space; Syringomyelia
PubMed: 22958075
DOI: 10.3171/2012.8.SPINE111059 -
Annals of Medicine and Surgery (2012) Oct 2021and importance: Head and neck paragangliomas are slowly growing benign tumors and they originate from specialized neural crest cells. We report an unusual combined...
INTRODUCTION
and importance: Head and neck paragangliomas are slowly growing benign tumors and they originate from specialized neural crest cells. We report an unusual combined glomus vagal and jugular tumor that was rarely described in the literature to the best of our knowledge.
CASE PRESENTATION
A 51 years old female with no pathological history was presented to our ENT department with 6 months' history of a right latero cervical swelling gradually increasing in size associated with a swallowing difficulties and hoarseness. Preoperatively clinical examination had found vagal and hypoglossal nerve paralysis. Cervical CT scan and MRI had shown glomus jugular tumor. The patient underwent a surgical excision with severe swallowing difficulties and facial palsy in the immediate postoperative period with a mild recovery afterwards.
CLINICAL DISCUSSION
Paragangliomas of the mesotympanum and jugular foramen most commonly present as a vascular middle ear mass. The most common presenting symptom is pulsatile tinnitus occurring in 80% followed by hearing loss (60%). Dysfunction of cranial nerves traversing the jugular foramen may be commonly encountered with resultant abnormalities of speech, swallowing and airway function. Vagal paragangliomas are the least common of the three primary craniocervical paragangliomas. The most common presenting sign is the presence of a painless neck mass accompanied occasionally by dysphagia and hoarseness. The association of both glomus vagal and jugular tumor is rarely described in the literature to the best of our knowledge.
CONCLUSION
Head and neck paragangliomas are slowly growing benign tumors and they originate from specialized neural crest cells. Vagal paragangliomas are the least common of the three primary craniocervical paragangliomas. The association of both glomus vagal and jugular tumor is rarely described in the literature to the best of our knowledge. The choice of treatment depends on the location, size, and also biologic activity of the tumor as well as the physical condition of the patient.
PubMed: 34691440
DOI: 10.1016/j.amsu.2021.102918 -
AJNR. American Journal of Neuroradiology Jan 1995To define the variations of the courses of the cranial nerves and the inferior petrosal sinuses as they enter and traverse the jugular foramen.
PURPOSE
To define the variations of the courses of the cranial nerves and the inferior petrosal sinuses as they enter and traverse the jugular foramen.
METHODS
Thirty-nine cadaveric specimens containing the jugular foramen were scanned with 1-mm contiguous axial and coronal CT sections. Each specimen was dissected to evaluate the position of the cranial nerves and inferior petrosal sinus as they entered the jugular foramen.
RESULTS
The glossopharyngeal nerve entered the most superior, anterior, and medial aspect of the jugular foramen and descended in the anterior portion of the jugular foramen, often within a groove. The vagus and accessory nerves could not be separated by CT. They entered the jugular foramen most often anterior or anterior and inferior to the jugular spine of the temporal bone and descended in a position ranging from medial to anterior to the jugular vein. The inferior petrosal sinus most often coursed inferior to the horizontal portion of the glossopharyngeal nerve and entered the jugular system in the jugular foramen, at the exocranial opening or below the skull base. A pars nervosa and pars venosa could be identified only at the endocranial opening, where the jugular spine separated the pars nervosa containing the inferior petrosal sinus and three cranial nerves from the pars venosa containing the jugular vein.
CONCLUSION
Our evaluation demonstrated anatomic variation in the area of the jugular foramen.
Topics: Accessory Nerve; Cranial Sinuses; Dissection; Glossopharyngeal Nerve; Humans; Jugular Veins; Occipital Bone; Petrous Bone; Skull; Temporal Bone; Tomography, X-Ray Computed; Vagus Nerve
PubMed: 7900591
DOI: No ID Found -
Saudi Journal of Anaesthesia Jan 2015Stylomastoid foramen is an important site for Nadbath facial nerve block. Exact localization of foramen holds the key to success, thus decreasing the complications. Wide...
BACKGROUND
Stylomastoid foramen is an important site for Nadbath facial nerve block. Exact localization of foramen holds the key to success, thus decreasing the complications. Wide racial variation exists in position of stylomastoid foramen in different population groups.
AIM
The aim was to study the morphometry of stylomastoid foramen and its location with respect to nearby anatomical landmarks.
MATERIALS AND METHODS
A total of 100 dry skulls (60 male and 40 female) were studied to locate the position of center of stylomastoid foramen (CSMF) with respect to tip and anterior border of the mastoid process and jugular foramen (JF). Along with this angle between antero-posterior line passing through the tip of the mastoid process and line joining the tip with stylomastoid foramen was also measured.
RESULT
In 83.51% sides of skulls, the most common position of foramen was found to be anterior to the line passing through anterior border of the mastoid process. The mean distance of center of foramen from the tip of the mastoid process was 15.26 ± 1.4 mm on right and 14.32 ± 1.8 on the left side (P < 0.001) and from JF was 12.28 ± 1.9 mm and 12.96 ± 2.1 mm on the right and left sides, respectively (P < 0.01). The position of CSMF was found at an angle of 66.57° ± 2.6° and 65.96° ± 1.8° on the right and left sides, respectively from the tip of the mastoid process.
CONCLUSION
This study makes possible the identification of the exact position of stylomastoid foramen and its application in facial nerve block.
PubMed: 25558201
DOI: 10.4103/1658-354X.146314 -
What are the limits of endoscopic sinus surgery?: the expanded endonasal approach to the skull base.The Keio Journal of Medicine Sep 2009The advent of endoscopic technologies and techniques has expanded the limits of conventional endoscopic sinus surgery. The expanded endonasal approach describes a series... (Review)
Review
The advent of endoscopic technologies and techniques has expanded the limits of conventional endoscopic sinus surgery. The expanded endonasal approach describes a series of surgical modules in the sagittal and coronal planes that allow surgical access to the entire ventral skull base. The sagittal plane extends from the frontal sinus to the second cervical vertebra. The coronal plane extends from the midline to the roof of the orbit, the floor of the middle cranial fossa, and the jugular foramen. Key principles of endonasal skull base surgery are choosing a surgical corridor that minimizes the need for neural and vascular manipulation, team surgery, use of the endoscope to enhance visualization, and bimanual tumor dissection under direct visualization. Particular challenges of the expanded endonasal approach are identification of anatomical structures using unfamiliar landmarks, hemostasis, and dural reconstruction. Over the last decade with more than 1000 completely endonasal skull base surgeries, we have demonstrated that endoscopic endonasal surgery of the skull base can be performed with minimal morbidity and mortality. The introduction of the septal mucosal flap for dural reconstruction has decreased the incidence of postoperative cerebrospinal fluid leaks to less than 5%. Early data suggests that oncological outcomes for malignant sinonasal tumors with skull base involvement are comparable to conventional techniques. Proper training in endonasal surgical techniques is essential to prevent unnecessary morbidity and achieve good outcomes.
Topics: Brain Stem; Endoscopy; Granuloma; Humans; Magnetic Resonance Imaging; Meningioma; Minimally Invasive Surgical Procedures; Nasal Cavity; Nose Neoplasms; Skull Base; Tomography, X-Ray Computed
PubMed: 19826209
DOI: 10.2302/kjm.58.152