UNASSIGNED: A case of Eustachian tube dysfunction following percutaneous balloon compression (PBC) of the trigeminal ganglion led us to investigate aural complications of PBC and similar procedures. We aimed to clarify both the physiological effects of compression of the trigeminal ganglion on aural function and the possibility of puncture of the Eustachian tube during placement of the needle.
UNASSIGNED: We reviewed the anatomy of the Eustachian tube in relation to the foramen ovale and the aural structures supplied by the trigeminal nerve through cadaveric study. Following CT scanning, neuronavigation was used to guide a needle into Meckel\'s cave of a cadaver. Dissection was subsequently carried out with the needle in-situ to assess the proximity of the needle to the Eustachian tube and other structures. A literature review of aural complications of foramen ovale procedures using Ovid Medline, PubMed, and Google Scholar databases was undertaken.
UNASSIGNED: Our literature review summarises the relationship of the Eustachian tube to the foramen ovale, the nerve supply of aural structures from the trigeminal nerve and examines previously reported post-operative aural complications. From our anatomical study, at its closest point, the needle was 7 mm from the Eustachian tube.
UNASSIGNED: The trigeminal nerve supplies both the tensor tympani and tensor veli palatini muscles and percutaneous procedures may, therefore, lead to aural symptoms. Also, the path of the needle is close to the Eustachian tube and can be punctured during these procedures. The authors recommend discussing aural complications during consent for these procedures.

Type III redundancy of the foramen ovale flap (RFOF) mimics hemodynamic changes of mitral stenosis(MS), which has not been particularly highlighted in previous literature but carries a favorable prognosis.

BACKGROUND: Patients with medication-resistant disabling epilepsy should be considered for potential epilepsy surgery. If noninvasive techniques are unable to identify the location of the seizure onset zone (SOZ), it becomes necessary to consider intracranial investigations. Stereo-electroencephalography (SEEG) is currently the preferred method for such monitoring, however foramen ovale (FO) electrodes offer a less invasive alternative that may be suitable in certain situations. Previous studies have demonstrated the effectiveness of FO electrodes in suspected mesial temporal epilepsy, nevertheless, increased experience with FO electrode use could further enhance their safety and efficacy. Therefore, we conducted an analysis of recent FO electrode investigations to assess their utility in surgical decision making, post resection outcomes, and complication rates.
METHODS: We conducted a retrospective analysis of 61 patients who underwent FO placement at Mass General Brigham between 2009 and 2020. Patient and seizure characteristics, preoperative investigation data, and seizures outcomes were collected. In addition, identified predictors of FO utility using logistic regression.
RESULTS: A total of 61 patients were identified. FO evaluation localized the SOZ in 56 % of patients. Complications were encountered in 1.6 % of patients. Subsequent surgical resection was pursued by 49 % of patients, with 56 % becoming seizure free, and 67 % having favorable seizure outcomes at last follow-up. Multivariate analysis identified younger patients with a higher number of preoperative ASMs as more likely to undergo subsequent treatment, however, these features were not predictive features of SOZ localization, seizure freedom, or favorable seizure outcomes. In patients with bitemporal or cross-over onsets on scalp EEG, FO was able to identify the SOZ in 79 %, whereas in patients with discordant or unclear onset, the rates were 71 % and 45 %, respectively.
CONCLUSIONS: In a contemporary cohort, FO electrode placement had a low complication rate and a high utility primarily in cases of unclear laterality of mesial temporal onsets or discordance between scalp EEG and other pre-FO investigation data in cases of suspected mesial temporal onsets.

Paradoxical embolism through the foramen ovale is a rare and devastating event requiring urgent treatment. Herein, we present the case of a 23-year-old male who presented with a pulmonary embolism complicated by a left renal artery paradoxical embolism. Urgent vacuum-assisted thrombo-aspiration restored normal perfusion of the left kidney within 5 hours. The patient had a patent foramen ovale and heterozygous thrombophilia. However, a radioisotopic scan performed 2 years later revealed an unexpected decrease in left renal perfusion. Therefore, despite the angiographic success, functional evaluation using a renal scan should be performed to assess renal function.

OBJECTIVE: Introducing a preoperative image simulation technique to streamline the visualization of the foramen ovale in percutaneous microcompression.
METHODS: Twenty-five trigeminal neuralgia patients were included in the study. Preoperative cranial computed tomography scans were processed with 3D Slicer software to create simulated fluoroscopic skulls. The angulations required for precise visualization of the foramen ovale were established via simulated anteroposterior imaging. These simulations informed the C-arm\'s angulations for foramen ovale targeting during surgery.
RESULTS: The preoperative simulations accurately forecasted skull rotation angulations, aligning closely with intraoperative observations with negligible discrepancies (0-2 degrees). In 17 patients, the foramen ovale was distinctly visible, while in 8 patients, it was partially obscured yet discernible using the simulated angles. Nonvisible of the foramen ovale did not occur. Postoperative pain relief and complications were recorded.
CONCLUSIONS: Based on our initial findings, the application of preoperative image simulation shows significant referential value in achieving accurate visualization of the foramen ovale in percutaneous microcompression for trigeminal neuralgia.

Atypical trigeminal neuralgia (TN), usually caused by nonvascular compression, lacks a clearly localized trigger and complete remission periods. Although variations of foramen ovale may compress the mandibular nerve branch of the trigeminal nerve, resulting in atypical TN, only a few case reports are reported in the literature. The authors describe a case of a 50-year-old female diagnosed with atypical TN for two months. A high-resolution computed tomography imaging revealed an osteophyte of the left foramen ovale that may compress the mandibular nerve branch of the trigeminal nerve. The patient underwent osteophyte resection, and the pain disappeared completely and immediately after surgery without recurrence in the follow-up to six months. The numbness was also relieved slightly. This case provides a new perspective on the clinical diagnosis and treatment of patients with atypical TN.

OBJECTIVE: To analyze the prenatal and postnatal outcomes of fetuses with d-TGA and to determine whether prenatal echocardiography may predict postnatal urgent BAS.
METHODS: A retrospective study of fetuses with d-TGA, for which fetal echocardiography was performed at our tertiary hospital from January 2018 to May 2023. We assessed the appearance of the septum primum and the FO flap in the four-chamber view as to whether the FO had a restrictive appearance during measurement of the diameter of the FO at its maximal angle to the attachment point. Color Doppler was used to detect VSDs and measure its diameter both in the four-chamber view and when visualizing the outlets of the great arteries in the sagittal section of the heart.
RESULTS: During the study period, 64 fetuses were diagnosed with d-TGA, which was also confirmed postnatally. Of these, 16 fetuses were excluded due to additional cardiac anomalies or the inability to reach the mother. In total, 48 cases were included in this series. In our study, the FO diameter was significantly decreased in the urgent BAS group, compared with the fetuses without urgent BAS (5.1 mm vs 6.3 mm). A cut off of 6 mm for the FO diameter (sensitivity, 73.3 %; specificity, 72.2 %; area under the curve [AUC], 0.764) and 3.2 mm for the VSD diameter (sensitivity, 75 %; specificity, 75 %; AUC, 0.728) suggested urgent BAS.
CONCLUSIONS: Prenatal echocardiography performed after 37 weeks of gestation in fetuses with d-TGA provides valuable information to estimate the need for postnatal urgent BAS that would prevent immediate life-threatening complications.

BACKGROUND: Radiofrequency thermorhizotomy (TRZ) is an established treatment for trigeminal neuralgia (TN). TRZ can result risky and painful in a consistent subset of patients, due to the need to perform multiple trajectories, before a successful foramen ovale cannulation. Moreover, intraoperative x-rays are required.
METHODS: TRZ has been performed by using a neuronavigated stylet, before trajectory planning on a dedicated workstation.
CONCLUSIONS: Navigated-TRZ (N-TRZ) meets the expectations of a safer and more tolerable procedure due to the use of a single trajectory, avoiding critical structures. Moreover, N-TRZ is x-ray free. Efficacy outcomes are similar to those reported in literature.

OBJECTIVE: To study the value of three-dimensional CT (3D-CT) reconstruction by comparing the surgical effects of C-arm and 3D-CT in the treatment of trigeminal neuralgia (TN) by percutaneous balloon compression (PBC).
METHODS: A total of 136 patients were included from May 2018 to February 2019. Among them, 65 patients underwent PBC treatment with 3D-CT and others with C-arm. During 3D-CT-guided operation, 3D-CT reconstruction software was used to analyze and measure the distances from the internal orifice of Foramen ovale (FO-I) and the external orifice of Foramen ovale (FO-E) to the top of the balloon (BT) and the petrous bone ridge (PR). The data, including the angle between the puncture needle direction and the zygomatic arch, petrous bone ridge, and slope, were used to assist the puncture and balloon plasty. Postoperative follow-up for more than five years was performed to evaluate the efficacy and pain recurrence.
RESULTS: The distance from FO-E to PR was (2.10 ± 0.16)cm, the average distance from FO-I to BT was (2.39 ± 0.07)cm, and the average angles between the puncture needle and zygomatic arch, slope, and petrous bone ridge were (56.19 ± 5.59)°, (69.12 ± 6.92)°, and (104.49 ± 6.46)°, respectively. One (1.5 %) patient in the 3D-CT group and three (4.2 %) patients in the C-arm group failed to receive PBC treatment because of failure of FO puncture (P = 0.032).In terms of postoperative pain improvement, 3D-CT group achieved better results than the C-arm group (P = 0.043). There were no significant differences in the rates of major complications and short-term recurrence (P = 0.926) between the two groups after surgery, but the five-year recurrence rate in the 3D-CT group was lower than that in the C-arm group (P = 0.032).
CONCLUSIONS: By guiding the angle and depth of puncture, the intraoperative application of 3D-CT reconstruction technology can improve the accuracy of foramen ovale puncture and alleviate postoperative pain, and also maintain long-term postoperative pain relief, which can be used as a potentially better guidance method to improve the surgical efficacy of PBC.

UNASSIGNED: The assessment of cranial foramina is an important part of the objective diagnostic and therapeutic study relevant to pathologies involving structures of the skull base. The study of the foramen ovale not only holds significance for anatomical development but also bears profound surgical importance, such as in trigeminal neuralgia, and diagnostic importance in tumors and various types of epilepsy. It becomes relevant in fine-needle aspiration techniques in perineural tumor procedures, for electroencephalographic analysis in seizures, and therapeutic procedures such as percutaneous trigeminal rhizotomy for trigeminal neuralgia.
UNASSIGNED: A cross-sectional study at the Department of Neurosurgery, Specialties Hospital, La Raza National Medical Center, Mexico City, involved 70 patients aged >18 years who underwent a single skull computed tomography scan between July 2023 and March 2024. Patients with sufficient scan quality and optimal visualization of skull base foramina were included in the study. Measurements of tomographic images were taken using Inobitec\'s DICOM file viewer. Data analysis in Microsoft Excel yielded mean, standard deviation, and 95% confidence interval (CI) for morphometric parameters of the foramen ovale.
UNASSIGNED: Analysis of tomographies from 70 patients revealed a total of 140 foramen ovale, evenly split between 25 males (35.7%) and 45 females (64.3%). The measurements for the maximum anteroposterior diameter, transverse diameter, and surface area of all foramina were as follows: 6.61 ± 0.25 mm (95% CI), 3.97 ± 0.21 mm (95% CI), and 20.84 ± 1.58 mm2 (95% CI), respectively. Specific measurements for the right and left sides were obtained: for the right side, 6.59 ± 0.26 mm (95% CI) and 3.89 ± 0.21 mm (95% CI) for the maximum anteroposterior and transverse diameters, respectively, and 20.38 ± 1.62 mm2 (95% CI) for the surface area. For the left side, the measurements were 6.63 ± 0.24 mm (95% CI), 4.05 ± 0.21 mm (95% CI), and 21.31 ± 1.55 mm2 (95% CI) for the maximum anteroposterior diameter, transverse diameter, and surface area, respectively. The maximum and minimum dimensions for anteroposterior and transverse diameters were 10.67 mm, 4.41 mm, 7.09 mm and 2.36 mm, respectively, with a corresponding range for the surface area of 10.16 mm2-44.13 mm2. The average minimum distance between the foramen ovale and the foramen spinosum was 2.32 ± 0.24 mm (95% CI). In males, the average size of the foramen ovale was 23.66 ± 1.61, which was 22% larger than the average size in females (19.28 ± 1.45) (P = 0.0001).
UNASSIGNED: The foramen ovale is one of the main anatomical structures of the skull base, and besides that, it is complex and not directly accessible for clinical evaluation, useful information can be obtained through morphometric analysis. The present study provides specific anatomical data with morphological patterns to increase the understanding of the characteristics of the foramen ovale in the Mexican population. These are intended to be helpful in the pursuit of acknowledging the morphometrics and thus being able to plan neurosurgical procedures in the middle cranial fossa.