Jugular Foramen Research Articles

RARE TUMORS OF POSTERIOR CRANIAL FOSSA IN ADULTS

Objectives Tumors arising in the posterior cranial fossa pertain to a special category of neoplasm in the manner that they can cause cerebellar syndrome, obstructive hydrocephalus, brainstem compression – cranial nerve dysfunction – and herniation. In the cerebellopontine angle, the most common tumors are acoustic neuromas followed by meningiomas. Among the petroclival tumors, the most common benign tumors are meningiomas and the most common malign tumors are chordomas and metastases. Among jugular foramen tumors, the common tumors are schwannomas, paragangliomas and meningiomas. We report our unit’s experience with the neurosurgical management of rare posterior cranial fossa tumors as compared to the main literature results, taking into consideration the clinical, radiological aspects and the outcome. Materials and Methods Retrospective analysis of a single unit cohort of patients diagnosed with rare posterior cranial fossa tumors, who underwent surgical treatment in the Neurosurgery I Department of the University Emergency Hospital Bucharest between 2017 and 2024. Relevant literature review was analyzed, as well as serial clinical examinations, imaging studies, and operative records were taken into consideration. Conclusions Depending on the location, size, and pathology of the posterior cranial fossa tumors, there are different treatment options, which include microsurgical resection, observation, stereotactic radiotherapy. These type of lesions still represent a challenge and require electing the most suitable approach whilst preserving the neurologic function of the patient.

NCOG-25. STEREOTACTIC RADIOSURGERY VERSUS SURGICAL MICRODISSECTION FOR JUGULAR FORAMEN SCHWANNOMAS: A RETROSPECTIVE COMPARATIVE STUDY

Abstract INTRODUCTION Jugular foramen schwannomas (JFS) are rare, benign tumors arising from lower cranial nerves. Given their delicate location, surgical microdissection carries a substantial risk of neurological morbidity. Stereotactic radiosurgery (SRS) presents an alternative, particularly for smaller or residual tumors. OBJECTIVE This study aims to compare the outcomes and symptomatic improvements between these two treatment modalities. METHODS We conducted a retrospective analysis of 32 patients with JFS who underwent SRS (13 cases [40.6%]) or surgical dissection (19 cases [59.4%]) as their primary management at Stanford Medical Center between 1998 and 2024. Outcomes included progression-free survival (PFS), post-management adverse events based on common terminology criteria for adverse events (CTCAE), symptom improvement, overall survival (OS), and the necessity for secondary interventions. RESULTS Significant differences were observed in baseline characteristics between the SRS and surgery groups, including mean age (62.52 vs. 46.87 years, p<0.001), mean largest diameter (34.38 vs. 53.66 mm, p=0.02), and median total tumor volume (6.50 vs. 19.70 mm3, p=0.009). There were no significant differences in sex or lesion shape (dumbbell vs. non-dumbbell shaped). After adjusting for baseline characteristics, no significant differences were noted in PFS (85.71 vs. 77.77%), OS (92.3 vs 100%), symptom improvement (61.53 vs. 52.63%) or mean CTCAE grade (1.31 vs. 1.58) between the SRS and surgery groups. SRS patients had significantly lower odds of requiring secondary treatment procedures after their primary intervention as compared to those in the surgery group (OR=0.01, 95% CI: 0.0001-0.59, p=0.02). CONCLUSION Both SRS and surgery provide exceptional outcomes for JFS with no significant differences in PFS, OS, CTCAE grades, or symptom improvement between the two groups. However, SRS patients had lower odds of requiring secondary interventions for JFS. This is among the first studies comparing surgical microdissection and SRS for JFS. Future controlled prospective studies are necessary to derive more definitive conclusions.

Primary jugular foramen fibrous dysplasia: surgically nuanced video of extradural infratemporal transjugular approach. Illustrative case.

Fibrous dysplasia of the bone is a disease caused by a somatic GNAS mutation that affects craniofacial bones and can have a mass effect on different neurovascular structures. The authors present the first case of primary jugular foramen fibrous dysplasia with occlusion of the transverse and sigmoid sinuses. A 33-year-old man presented with a history of dizziness and occasional dysphagia over the past year. Magnetic resonance imaging showed a uniform enhanced mass in the left jugular foramen, with complete blockage of the adjacent transverse and sigmoid sinuses. The computed tomography scan revealed a cystic bone lesion of the jugular foramen. The patient underwent a gross-total removal of the tumor through an infratemporal transjugular approach with complete preservation of the lower cranial nerves. This first reported case of primary jugular foramen fibrous dysplasia highlights the importance of considering this diagnosis when evaluating jugular fossa lesions. Understanding the anatomy of the infratemporal and jugular fossae, along with proficiency in microsurgical techniques, is essential for removing such tumors while preserving cranial nerve functions and the patient's quality of life. https://thejns.org/doi/10.3171/CASE24396.

Endoluminal Sigmoid Sinus Occlusion During Jugular Foramen Tumor Surgery: Novel Technique, Operative Nuances, and Clinical Experience With 33 Patients.

Surgery of jugular foramen tumors (JFTs) often requires vascular control by means of ligating the internal jugular vein and sigmoid sinus (SS) to allow intrabulbar access. Occlusion of the SS traditionally involves presigmoid and retrosigmoid durotomies allowing introduction of ligature devices, predisposing to cerebrospinal fluid (CSF) leakage and pseudomeningoceles. We describe a simple and novel endoluminal sigmoid sinus occlusion (ESSO) technique with Gelfoam that is entirely extradural. An extended anterolateral infralabyrinthine approach with ESSO was performed in 33 patients with JFTs. After ligating the internal jugular vein, the SS is opened and Gelfoam is placed endoluminally into the proximal SS. Care is taken to avoid occlusion of the venous outflow of the vein of Labbe to avoid temporal lobe venous infarction. Hemostatic gelatin matrix is injected distally to stop venous backflow from the inferior petrosal sinus. The jugular venous system is isolated, and the outer jugular wall can be opened to expose the JFT for resection. There were no complications of temporal lobe venous infarction or postoperative hematoma observed. Four patients with intradural tumor extension developed pseudomeningoceles. For patients with purely extradural JFTs, none developed postoperative incisional CSF leaks and one had pseudomeningocele. This ESSO technique is fast and effective, permitting occlusion of the SS during JFT surgery. It has the advantage of being entirely extradural, avoiding durotomy which can result in postoperative CSF leak. It is important to keep the Gelfoam distal to the transverse-sigmoid junction to avoid occlusion of the vein of Labbe inlet and temporal lobe venous infarction.

Comparison of two biologically effective dose calculation models applied to single fraction stereotactic radiosurgery

BackgroundRecent studies suggest strong correlations between Biologically Effective Doses (BED) and single fraction stereotactic radiosurgery treatment outcomes, as demonstrated for vestibular schwannomas (VS), arterio-venous malformations and pituitary adenomas. The BEDs calculated in these studies consider an uniform dose delivery where the spatio-temporal aspects of dose delivery were neglected. PurposeThe aim of the study is to quantify the discrepancies between the BED values calculated with a simplified model of uniform dose delivery against the more complex model that incorporates the temporo-spatial incrementation of dose delivery and the bi-exponential effect of the sub-lethal damage repair. MethodsA software tool that computes the BED distributions based on individual isocenter dose matrices extracted from the GammaPlan (Elekta) treatment planning was developed. Two cohorts 5 VS and 5 jugular foramen schwannoma cases of various tumor volumes and isocenter number were utilized to benchmark the method. Their BEDs covering 98% of tumor volumes were compared against those determined with the uniform delivery model. ResultsThe BEDs covering 98% of the tumor volumes as calculated with both models show an approximately linear dependency with the treatment time. For all studied cases, the uniform delivery model overestimates the BEDs calculated with the full spatio-temporal delivery model. This discrepancy seems to accentuate with the tumor volume and treatment complexity. ConclusionsDespite their resemblance, the BED distributions provide a plethora of BED measures more suitable to characterize clinical outcomes than the unique peripheral BED value calculated with the simplified model of uniform dose delivery.

Sheep Head Cadaveric Model for the Transmeatal Extensions of the Retrosigmoid Approach

AbstractThe transmeatal extension of the retrosigmoid approach is an important procedure used in the treatment of various pathologies affecting the posterior fossa, petroclival region, and jugular foramen. Mastering this technique requires a high level of manual skill, particularly in temporal bone drilling. The objective of this study was to describe an easily accessible and cost-effective model of the transmeatal extension of the retrosigmoid approach using cadaveric sheep heads. Five cadaveric sheep heads, fixed in alcohol and formalin with intravascular-colored silicone injection, were prepared for this study. Two heads (four sides) were designated for illustrative anatomical specimens, while three heads (six sides) were used for surgical simulation. Additionally, one head was used to prepare and dissect a dry skull. All critical steps of the transmeatal approach, including both supra- and inframeatal extensions, were successfully replicated on the model. A comparative anatomical analysis was conducted, focusing on the technical nuances of the model. The cadaveric sheep head serves as an effective model for the retrosigmoid approach with transmeatal extensions, primarily for training manual haptic skills. While the sheep model cannot precisely replicate human anatomy, it still offers valuable training opportunities for neurosurgeons, particularly when human cadaveric specimens are unavailable.

Occipital condyle syndrome due to small-cell lung carcinoma: A case report.

Skull base metastases, including those from small-cell lung carcinoma (SCLC), can present with various syndromes depending on the site of involvement, such as orbital syndrome, parasellar syndrome, middle fossa syndrome, jugular foramen syndrome, and occipital condyle syndrome (OCS). One such example is OCS, which consists of unilateral occipital headache accompanied with ipsilateral hypoglossal palsy. This case report describes a 51-year-old man initially diagnosed with OCS, which led to the discovery of systemic bone metastases from SCLC. Magnetic resonance imaging showed lesions in the occipital condyle and hypoglossal canal, while positron emission tomography-computed tomography identified a lung mass and widespread metastases. SCLC is highly aggressive and metastatic, with the bone being a common site of spread. In this case, the OCS preceded the diagnosis of the underlying malignancy. Prompt diagnosis and treatment are crucial, as patients with OCS often have advanced disease. This case highlights the importance of considering SCLC as a potential etiology for OCS, given the propensity for bone metastases. Early recognition and evaluation of OCS is essential to initiate appropriate management.

Surgical resection and reconstruction techniques for jugular foramen schwannoma

IntroductionJugular foramen schwannomas present formidable challenges due to their deep-seated location and complex anatomical constraints, leading to significant difficulties in tumor excision, postoperative complications further hinder surgical interventions in this area. We aim to explore and summarize surgical and reconstruction techniques for jugular foramen schwannomas to enhance patient outcomes. Materials and methodsIn a retrospective analysis, we reviewed the surgical approaches and reconstruction techniques utilized in 31 patients undergoing surgical resection for jugular foramen schwannomas from January 2018 to the present. Our goal was to summarize the materials and methods used for skull base reconstruction in this region and propose a clinically applicable procedural framework for surgical intervention. ResultsResults revealed that 28 patients underwent treatment via the far lateral paracondylar approach, while 3 patients opted for the suboccipital retrosigmoid approach. Among them, 15 patients underwent surgical cavity tamponade. Additionally, we summarized three methods of dural reconstruction in the surgical area. Postoperative temporary complications showed varying degrees of improvement during follow-up, leading to an overall favorable prognosis. ConclusionOur study presents clinical insights into the surgical resection and skull base reconstruction of jugular foramen schwannomas. We discuss the selection of surgical approaches, intraoperative landmarks, and reconstruction techniques aimed at improving patient outcomes effectively.

Exploration of technique for preservation of external-middle ear structure in surgery of jugular foramen paraganglioma （appended 2 case reports）

Objective:To investigate the feasibility and effect of the modified surgery of the classic infratemporal fossa type A approach for the surgical treatment of jugular foramen paraganglioma with preservation of the external and middle ear structures. Methods:The medical data of 2 patients with jugular foraminal paraganglioma treated by sublabyrinthic-transmastoid approach were retrospectively analyzed. The clinical feature, degree of tumor resection, postoperative facial nerve function and hearing retention, and the incidence of postoperative complications were evaluated. Results:Two patients were both female, and were pathologically confirmed as paraganglioma. The tumor of case 1 was staged as C2De1, and case 2 as C1De1. Tumors were completely resected in both patients. Case 1 suffered infection after surgery, with residual tympanic membrane perforation and mixed deafness. Case 2 developed mild facial paralysis（grade Ⅱ） after surgery, and recovered after symptomatic treatment. There was no tumor residue or recurrence during half a year of follow-up. Conclusion:Surgical treatment of certain paragangliomas in the jugular foramen with a combined sublabyrinthic-transmastoid and upper neck approach might achieve both complete resection of the tumor and preserving the structure and function of the outer-middle ear. This procedure is suitable for paragangliomas restricted in the jugular foramen area, with no or limited involvement of the internal carotid artery（C1 or C2）, and with no or mild hearing loss.

New progress in the diagnosis and treatment of jugular paragangliomas

Jugular paraganglioma is the most common neoplasms in the jugular foramen. It is a slow-growing wiht abundant blood supply, and is intimately associated with critical neurovascular structures at the skull base. In this paper, the latest advance in pathophysiology, surgical treatment, radiotherapy were reviewed based on previous literature, providing reference for clinical diagnosis, treatment and future research.

A case report of giant jugular foramen paraganglioma

To investigate the clinical experience of glomus jugulare paraganglioma by presenting a case of giant glomus jugulare paraganglioma. The clinical data of 1 case of giant glomus jugulare paraganglioma with unilateral anacousia and pulsatile tinnitus admitted to our department was retrospectively analyzed, and the relevant literature was reviewed to summarize the characteristics of the disease. The tumor tissue in the jugular venous foramen region was completely resected, with complete preservation of the facial nerve during the operation. There was no tumor recurrence during the 2-year postoperative follow-up period. With nonspecific clinical symptoms and a high rate of early misdiagnosis The giant glomus jugulare paraganglioma case only manifested as symptoms of unilateral anacousia and pulsatile tinnitus is clinically rare. The intraoperative safe resection of the tumor, maximum preservation of facial nerve function remains the focus of surgery.

The surgical outcomes in management of jugular foramen paragangliomas with tension free anterior rerouting of the facial never and tunnel packing of the inferior petrous sinus

Objective:The aim of this study is to evaluate the safety and efficacy of surgical interventions ofjugular foramen paragangliomas（JFP） utilizing modified surgical techniques, tensionfree anterior rerouting of the facial nerve and tunnel-packing or push-packing of the inferior petrous sinus. Methods:A retrospective analysis was conducted on a cohort of 88 patients diagnosed with JFP and treated at the Eye Ear Nose and Throat Hospital of Fudan University（in Shanghai, China） from October 2010 to June 2021. The surgical outcomes were analyzed for tumor classification, intraoperative conditions, and function of the postoperative facial nerve（FN） and lower cranial nerve（LCN）. Results:The study included a total of 88 patients, gross total resection was achieved in 70 patients（79.5%）, near total resection was obtained in 17 patients（19.3%）, and one patient undergoing subtotal resection. The average of intraoperative blood loss was 448.3 mL. Additionally, 24 patients underwent surgical total anterior rerouting（TAR）, 18 patients underwent surgical total FN tension free anterior rerouting（TF-TAR）, and 18 patients underwent surgical FN partial FN tension free anterior rerouting（TF-PAR）. Good postoperative FN function（House-Brackmann Ⅰ-Ⅱ） was achieved in 62.5% of TAR group. In the TF-TAR and PF_TAR groups, good postoperative FN function was demonstrated in 88.9% patients. It showed a significantly improvement of the FN function following application of tension-free FN anterior rerouting technique（P=0.007）. Twenty patients（22.7%） suffered from at least one LCN deficit in the preoperative evaluation. The postoperative LCN deficits was correlated with the Fisch classification of tumors, which showed a lower incidence of LCN dysfunction in classes C1-C2（4.9%, 2/41cases） and poorer outcomes of LCN dysfunction in classes C3-D（8.5%,4/47cases ）, it was likely less impacted the LCN function in the early stage tumor. Conclusion:The application of modified surgical techniques of FN tension-free anterior rerouting and tunnel-packing of the inferior petrous sinus has been shown to effectively preserve the function of the FN and LCN, decrease intraoperative blood loss, and ultimately improve patients' postoperative quality of life.

Radiographic and neurological outcomes of Gamma Knife radiosurgery for lower cranial nerve schwannomas: a single-institution experience.

Gamma Knife radiosurgery (GKRS) is widely used for treating small- to medium-sized or postoperative residual, recurrent lower cranial nerve schwannomas (LCNSs). This study aimed to evaluate the radiographic and neurological outcomes of GKRS for LCNS. A total of 60 patients with 47 jugular foramen schwannomas (JFSs) and 13 hypoglossal nerve schwannomas (HNSs) who underwent GKRS were included. Dysphagia (40.4%) and hoarseness (23.4%) were the most common preexisting symptoms associated with JFS, whereas tongue deviation (53.8%) was prevalent in HNS. The median tumor volumes were 3.2 cm3 and 2.2 cm3 for JFSs and HNSs, respectively. The median marginal dose administered to the tumor was 13 Gy (range 12-15 Gy). The median follow-up duration was 52.8 months. Local tumor control was achieved in 91.5% of JFSs and 92.3% of HNSs. The preexisting neurological symptoms improved in 48.9% of patients with JFS and remained stable in 29.8%. However, 10 patients (21.3%) experienced exacerbation of symptoms associated with cranial nerves VII, VIII, IX, X, and XI. Among these, 3 patients (6.4%) exhibited persistent symptomatic deterioration. Patients with HNSs demonstrated a stable trajectory without symptom aggravation. Larger tumor volume and cystic portion were significantly associated with tumor progression (p = 0.017 and 0.003, respectively), and post-GKRS transient swelling was associated with neurological deterioration (p = 0.044). GKRS is an alternative treatment option for LCNS that reduces surgical morbidity and enhances tumor control. However, GKRS can potentially lead to neurological deterioration, necessitating extreme caution throughout the procedure, specifically for JFSs.

Results of surgical treatment of posterior cranial fossa meningiomas

Surgery of meningiomas of the posterior cranial fossa, due to its small volume and close anatomical relationship of neoplasms with the brain stem, cranial nerves, main arteries and venous collectors, remains one of the urgent problems of neurooncology. Despite the improvement of microsurgical techniques and neurophysiological control, maintaining a high level of quality of life after radical removal of meningiomas is still far from desired. Purpose of the study. Retrospective analysis and generalization of clinical results of surgical treatment of patients with meningiomas of the posterior cranial fossa. Material and methods. The paper analyzes the results of surgical treatment of 101 patient with meningiomas of the posterior cranial fossa of various localization (80 women (79.2 %) and 21 men (20.7 %), age 58.26 ± 1.00 years). According to the localization of meningiomas, they were distributed as follows: convexital – 49 (48.5 %), cerebellopontine angle – 22 (21.8 %), jugular foramen – 4 (4 %), petroclival – 16 (15.8 %), foramen magnum – 10 (9.9 %). Results. All patients underwent surgical removal of the formation. In 99 (98 %) one-stage and in 2 (1.9 %) cases of additional surgical intervention, in the form of external drainage according to Arendt and ventriculoperitoneal shunting, due to frolicking liquorodynamic disorders. Radical removal of meningioma (grade I according to Simpson scale) was achieved in 72 (71.3 %) of cases, tumor resection with coagulation of the tumor matrix zone (Simpson II) – in 21 (20.8 %), removal without resection and coagulation of the matrix, or leaving the extradural component of meningiomas (Simpson III) – in 8 (7.9 %). Conclusions. The results obtained on the basis of the complex use of modern neuroimaging diagnostic tools, microneurosurgery, optimal surgical approaches in combination with the mandatory intraoperative physiological control of the function of the brain stem and cranial nerves in the early postoperative period indicate an improvement in the functional state, and sometimes complete regression of the neurological symptoms in 58 (57.4 %) of operated patients. Complete regression of symptoms and restoration of the functional state was achieved in 30 (29.7 %) of cases, deterioration was noted in 17 (16.8 %) of the operated patients, mortality was 4.95 % (n = 5).

Stereotactic radio-neurosurgery for jugular foramen schwannomas

BackgroundStereotactic radiosurgery (SRS) represents a minimally invasive and valuable alternative for jugular foramen schwannomas (JFS), both as upfront and/or adjuvant treatment (in hybrid approaches).MethodsWe conducted a retrospective review of our cases treated at the Lausanne University Hospital (CHUV) from June 2010 to October 2023. Eleven patients underwent SRS, among whom three had prior surgery, two in our center in the frame of a planned combined approach and one in another center. Two patients received "volume-staged" SRS. The mean age at SRS was 60 years (median 68; range 29–83). Cranial nerve (CN) symptoms were present in six patients, while five were asymptomatic. The mean tumor volume at SRS was 2.1 cc (median 1.2; range 0.068–7.3 cc), with a 12 Gy marginal dose prescribed in all cases.ResultsThe mean follow-up period was 3.9 years (median 2, range 1–7). Cranial nerve function improved after SRS in six patients, while five remained stable. At the last follow-up, all tumors showed a decrease in volume, except for one patient, who underwent surgery at 18 months after SRS, for volumetric increase at 6 and 12 months, with further XII−th CN palsy and medulla oblongata compression. Although tumor decreased at 18 months, such patient needed microsurgical resection for symptom persistence and was further controlled. The mean tumor volume at 1 year post-SRS was 1.6 cc (median 0.55; range 0.028–7.77 cc), at 2 years was 1.31 cc (median 0.76; range 0.19–5), and at 3 years was 1.32 cc (median 0.59; range 0.23–4.8). No adverse radiation events were observed.ConclusionsStereotactic radiosurgery is considered a safe and effective treatment for jugular foramen schwannomas, ensuring high rates of tumor control in all patients over the long term. The cranial nerve function improved after SRS in the 6 patients who had deficits and the other 5 patients who had no deficits remained asymptomatic. For larger tumors, combined/hybrid approaches can be a valuable alternative, to obtain tumor control and to preserve neurological function.

Surgical management of chondrosarcomas of the skull-base and temporal bone.

To analyze the overall long-term outcome of surgically treated skull base and temporal bone chondrosarcomas. The medical records of patients with surgically treated skull base and temporal bone chondrosarcomas between 1983 and 2024 were thoroughly evaluated. Out of a total of over 5000 skull base surgeries performed at our center, only 29 patients had histopathologically confirmed chondrosarcomas of the skull base and temporal bone. The mean of patients age was 45.6, and the male-to-female ratio was 1.9:1. The most common symptoms included hearing loss (58.6%), tinnitus (41.4%), diplopia (31%), dysphonia (24.1%), dysphagia (20.7%), vertigo (10.3%), and dizziness (10.3%). The most frequent locations of lesions among the 29 patients are as follows: petroclival region (34.5%), jugular foramen (27.6%), petrous apex (17.2%), middle ear (13.8%), others (3.4%). TO, IFTA, IFTB, IFTC, POTS, and combined surgical approaches were commonly used. The rate of gross total removal and recurrence was 82.6% and 13.8% respectively. The follow-up duration of 6 patients was more than five years and less than ten years whereas ten patients had more than ten years of follow-up. Chondrosarcoma of the skull base and temporal bone is a very rare pathology. Due to its multiple potential sites of origin and histological specificity, it presents us with significant challenges. Gross total removal is the primary treatment for chondrosarcoma of the skull base and temporal bone. Personalized decision-making should be considered based on the following aspects: tumor, patient, and surgeon's factors. Postoperative radiation therapy is complementary to surgical treatment in grades II and III lesions to achieve long-term survival.

Clinical, Anatomical, and Histological Features of the Rhomboid Lip and Considerations for Surgery Using a Retrosigmoid Approach: A Retrospective Study

The rhomboid lip is a neural tissue encountered during cerebellopontine angle surgery, with differing shape and extent among individuals. This study aimed to investigate the variation of rhomboid lips during posterior fossa surgery. In this retrospective study, we examined posterior cranial fossa surgeries performed using a retrosigmoid approach. Rhomboid lips were classified according to thickness, extent, and appearance, with some subjected to histological analysis. T2-weighted magnetic resonance imaging (MRI) of rhomboid lips was conducted. Among 304 surgeries, rhomboid lips were observed in 75 patients who underwent schwannoma or meningioma resection, facial spasm-related neurovascular decompression, and other surgeries (37, 2, 32, and 4 patients, respectively). Rhomboid lips were categorized based on apparent thickness: thin membranous type, resembling an arachnoid membrane, and thick parenchymal type. Rhomboid lip extension was classified by position relative to the choroid plexus: non-extension, lateral extension, and jugular foramen (41, 22, and 12 patients, respectively). Veins were observed on the rhomboid lip surface in 37 cases. The rhomboid lip was visible in only one case (parenchymal jugular foramen type) on MRI. Histologically, the rhomboid lip comprised an ependymal cell layer, a glial layer, and connecting tissue. The glial layer thickness determined the rhomboid lip thickness, which was greater in the parenchymal type than in the membrane type. In 42 patients, the rhomboid lip was dissected, with no complications observed. Morphological classification of the rhomboid lip and understanding of its anatomical details contribute to safe surgical field development for neurosurgeons.

The intrabulbar or extrabulbar growth pattern and its surgical outcomes of jugular foramen paragangliomas.

This study is to define a subclassification system of jugular foramen paragangliomas (JFPs) and to demonstrate corresponding microsurgical outcomes of JFPs. Retrospective study. A single-center study. We conducted a retrospective review of the clinical data of 44 patients with JFPs who underwent surgical management. Extrabulbar(Be) tumor and intrabulbar(Bi) tumor are defined based on the growth patterns, receiver operating characteristic (ROC) curves of the imaging profile were generated and was confirmed based on intraoperative findings. Area Under Curve (AUC), accuracy, sensitivity, and specificity for diagnostic imaging were revealed. We also compared the correlation between the two growth patterns with Fisch's classification, blood loss, lower cranial nerves (LCNs) deficit. There are 27 (69%) cases of Bi tumor and 17 (39%) cases of Be tumor. Significant radiomics features between the two growth patterns were demonstrated, ROC curves achieved excellent AUCs for MRI sequences (T1W1 MRI, MR contrast-enhanced sequence, MR complex sequences and MR complex + DSA by 0.833, 0.833, 0.875, 0.944) and had statistically significant in diagnosis of two growth patterns (P<0.05). There was no statistical correlation between growth patterns of JFPs and intra-operative blood loss. Preoperative LCNs deficits and Fisch's classification of tumors were correlated with the growth patterns of JFPs (P < 0.05). We proposetd two growth patterns of JFPs in term of the inferior petrous sinus involvement. Identification of Bi or Be growth patterns preoperatively is helpful to design optimal surgical strategies and minimize postoperative complications.

Jugular foramen stenosis in external hydrocephalus in infants.

To measure the size of jugular foramina in infants affected by external hydrocephalus (EH) and in a control group, to support the hypothesis that a jugular foramen (JF) stenosis may determine dural venous sinus alterations and increased venous outflow resistance as main pathophysiological factor. Minimum, maximum, and mean values of JF areas were measured in a series of phase-contrast magnetic resonance venous angiography (angio MRV PCA3D) performed on 81 infants affected by EH. Results were compared with a group of 54 controls. Smaller JF area was significantly smaller in patients versus controls (43.1 ± 14.6 vs. 52.7 ± 17.8; p < 0.001) resulting in a significantly smaller mean JF areas in patients vs. controls (51.6 ± 15.8 vs. 57.0 ± 18.3; p = 0.043). In patients, smaller JF areas were significantly associated with higher venous obstruction grading score (VOGS) both on the right (p = 0.018) and on the left side (p = 0.005). Positional plagiocephaly (cranial vault asymmetry index > 3.5%) was more frequent among EH patients than controls (38/17) but the difference was not significant (p = 0.07). In the 38 plagiocephalic patients, JF area was smaller on the flattened side than the contralateral in a significant number of cases both in right (21/7) and left (9/1) plagiocephaly (p < 0.0005) as well as the mean area (48.2 + 16.4 mm2 vs. 57.5 + 20.7 mm2, p = 0.002) and VOGS was significantly higher on the plagiocephalic side than on the contralateral side (1.6 ± 1.1 vs. 1.1 ± 0.9, p = 0.019). In this series of infants affected by EH, the mean size of the ostium of both JF resulted significantly smaller than controls. JF stenosis was significantly associated with higher degrees of venous obstruction on both sides, suggesting a direct extrinsic effect of JF size on dural sinus lumen and possible consequent effect on venous outflow resistance. Positional plagiocephaly, when present, was associated with a decreased JF area and increased VOGS on the flattened side.

Jugular Foramen, Foramen Magnum Meningiomas

The jugular foramen, also known as the foramen magnum, is a highly intricate region of the skull base through which numerous critical blood vessels and nerves traverse. Meningiomas, the most common tumors in neurosurgical pathology, can arise at any location where the meninges are present, posing significant challenges. Meningiomas involving the jugular foramen and sublingual neural tube are particularly notable for their potential to extend from intracranial to extracranial sites, necessitating familiarity with extracranial anatomy, which is not typically encountered in clinical practice. A comprehensive understanding of anatomical characteristics, along with an ample field of view and working space, is crucial for handling the cerebellum, brainstem, and nerves meticulously. The use of surgical support tools such as neuromonitoring and navigation is essential for enhancing the safety of the procedure. Furthermore, preparedness for treatment options, rehabilitation, and adjunctive therapies is vital in the event of neurological symptoms such as those affecting the glossopharyngeal, vagal, or hypoglossal nerves.