Retrogasserian trigeminal radiofrequency-thermorhizotmoy for trigeminal neuralgia.

Based on a personal experience of 4200 surgeries, radiofrequency thermocoagulation is useful lesional treatment for those trigeminal neuralgias (TNs) not amenable to microvascular decompression (idiopathic or secondary TNs). Introduced through the foramen ovale, behind the trigemnial ganglion in the triangular plexus, the needle is navigated by radiology and neurophysiological testing to target the retrogasserian fibers corresponding to the trigger zone. Heating to 55-75 °C can achieve hypoesthesia without anaesthesia dolorosa if properly controlled. Depth of anaesthesia varies dynamically sedation for cannulation and lesioning, and awareness during neurophysiologic navigation. Proper technique ensures long-lasting results in more than 75% of patients.

Anatomic Variations of Foramen Ovale as a Predictor of Successful Cannulation in Percutaneous Trigeminal Rhizotomies.

BACKGROUND AND OBJECTIVES: Percutaneous trigeminal rhizotomies are common treatment modalities for medically refractory trigeminal neuralgia (TN). Failure of these procedures is frequently due to surgical inability to cannulate the foramen ovale (FO) and is thought to be due to variations in anatomy. The purpose of this study is to characterize the relationships between anatomic features surrounding FO and investigate the association between anatomic morphology and successful cannulation of FO in patients undergoing percutaneous trigeminal rhizotomy. METHODS: A retrospective analysis was conducted of all patients undergoing percutaneous trigeminal rhizotomy for TN at our academic center between January 1, 2010, and July 31, 2022. Preoperative 1-mm thin-cut computed tomography head imaging was accessed to perform measurements surrounding the FO, including inlet width, outlet width, interforaminal distance (a representation of the lateral extent of FO along the middle fossa), and sella-sphenoid angle (a representation of the coronal slope of FO). Mann-Whitney U tests assessed the difference in measurements for patients who succeeded and failed cannulation. RESULTS: Among 37 patients who met inclusion criteria, 34 (91.9%) successfully underwent cannulation. Successful cannulation was associated with larger inlet widths (median = 5.87 vs 3.67 mm, U = 6.0, P = .006), larger outlet widths (median = 7.13 vs 5.10 mm, U = 14.0, P = .040), and smaller sella-sphenoid angles (median = 52.00° vs 111.00°, U = 0.0, P < .001). Interforaminal distances were not associated with the ability to cannulate FO surgically. CONCLUSION: We have identified morphological characteristics associated with successful cannulation in percutaneous rhizotomies for TN. Preoperative imaging may optimize surgical technique and predict cannulation failure.

D-Transposition of the great arteries with restrictive foramen ovale in the fetus: the dilemma of predicting the need for postnatal urgent balloon atrial septostomy.

OBJECTIVE: Restrictive foramen ovale (FO) in dextro-transposition of the great arteries (d-TGA) with intact ventricular septum may lead to severe life-threatening hypoxia within the first hours of life, making urgent balloon atrial septostomy (BAS) inevitable. Reliable prenatal prediction of restrictive FO is crucial in these cases. However, current prenatal echocardiographic markers show low predictive value, and prenatal prediction often fails with fatal consequences for a subset of newborns. In this study, we described our experience and aimed to identify reliable predictive markers for BAS. METHODS: We included 45 fetuses with isolated d-TGA that were diagnosed and delivered between 2010 and 2022 in two large German tertiary referral centers. Inclusion criteria were the availability of former prenatal ultrasound reports, of stored echocardiographic videos and still images, which had to be obtained within the last 14 days prior to delivery and that were of sufficient quality for retrospective re-analysis. Cardiac parameters were retrospectively assessed and their predictive value was evaluated. RESULTS: Among the 45 included fetuses with d-TGA, 22 neonates had restrictive FO postnatally and required urgent BAS within the first 24 h of life. In contrast, 23 neonates had normal FO anatomy, but 4 of them unexpectedly showed inadequate interatrial mixing despite their normal FO anatomy, rapidly developed hypoxia and also required urgent BAS ('bad mixer'). Overall, 26 (58%) neonates required urgent BAS, whereas 19 (42%) achieved good O2 saturation and did not undergo urgent BAS. In the former prenatal ultrasound reports, restrictive FO with subsequent urgent BAS was correctly predicted in 11 of 22 cases (50% sensitivity), whereas a normal FO anatomy was correctly predicted in 19 of 23 cases (83% specificity). After current re-analysis of the stored videos and images, we identified three highly significant markers for restrictive FO: a FO diameter < 7 mm (p < 0.01), a fixed (p = 0.035) and a hypermobile (p = 0.014) FO flap. The maximum systolic flow velocities in the pulmonary veins were also significantly increased in restrictive FO (p = 0.021), but no cut-off value to reliably predict restrictive FO could be identified. If the above markers are applied, all 22 cases with restrictive FO and all 23 cases with normal FO anatomy could correctly be predicted (100% positive predictive value). Correct prediction of urgent BAS also succeeded in all 22 cases with restrictive FO (100% PPV), but naturally failed in 4 of the 23 cases with correctly predicted normal FO ('bad mixer') (82.6% negative predictive value). CONCLUSION: Precise assessment of FO size and FO flap motility allows a reliable prenatal prediction of both restrictive and normal FO anatomy postnatally. Prediction of likelihood of urgent BAS also succeeds reliably in all fetuses with restrictive FO, but identification of the small subset of fetuses that also requires urgent BAS despite their normal FO anatomy fails, because the ability of sufficient postnatal interatrial mixing cannot be predicted prenatally. Therefore, all fetuses with prenatally diagnosed d-TGA should always be delivered in a tertiary center with cardiac catheter stand-by, allowing BAS within the first 24 h after birth, regardless of their predicted FO anatomy.

Morphological variations and morphometry details of the foramen ovale in the Saudi population: a retrospective radiological study.

The foramen ovale is one of the essential foramina in the middle cranial fossa, more precisely, in the superior surface of the greater wing of the sphenoid bone. It has essential surgical and diagnostic significance since it serves as a surgical landmark, and crucial neurovascular vessels such as the mandibular nerve and accessory meningeal artery pass through it. Therefore, understanding the morphological and morphometric variations of the foramen ovale is essential for accurately identifying, diagnosing, and managing related pathologies. The study aimed to evaluate the morphological variations and morphometric details of the foramen ovale in the Saudi population. A radiological study was conducted to observe the measurements and the shapes of the foramen ovale in the skull with its anatomical variants. Retrospective data was collected from the Department of Radiology, King Fahad University Hospital, Saudi Arabia. The sample consisted of 100 human skulls from computed tomography scans, including 50 males and 50 females. The values for the mean length, width, and distance from the midline on the right side were 6.462 mm ± 1.681 mm, 4.897 ± 1.0631 mm, and 2.4565 ± 0.51275 mm, and 6.451 ± 1.6691 mm, 4.812 ± 1.0848 mm and 2.4290 ± 0.60039 mm for the left side, respectively. The foramen shape was oval in the majority (47%), followed by round shape (31%) with no bony outgrowths such as spur in the studied foramina. Furthermore, the morphometric variation between males and females was statistically insignificant (p-value>0.05). The observed variation of foramen ovale in this study has significant anatomical and clinical applications for various diagnostic and surgical procedures.

Anatomical Morphology and Related Angles of Foramen Ovale: A Three-dimensional Computed Tomography Reconstruction.

This study aimed to report the three-dimensional reconstruction of the foramen ovale (FO) based on computed tomography angiography and describe its shape and related angles. A retrospective analysis of 199 adult patients who were hospitalised at the Department of Neurosurgery, The Second Affiliated Hospital of Bengbu Medical College, Bengbu, China, from January to December 2020 was conducted. The original DICOM files of patients' computed tomography scans were processed by 3D Slicer software to reconstruct the three-dimensional skull. The morphological characteristics of the FO on both sides were analysed. Their size, related angles and volumes, and the differences between the two sides and gender were compared. A total of 398 FO from 199 patients were studied. The most frequent shape of the FO was oval, accounting for 54.27%. The mean lengths of the right and the left sides were 5.40±1.51 and 5.10±1.18mm, respectively. The mean width on the right and left sides was 3.23±1.16 and 3.33±1.19 mm, respectively. The FO is most commonly oval in shape. Clinicians may use the anatomical characteristics regarding the size and shape of the FO for diagnosis and treatment. Key Words: Foramen ovale, Computed tomographic angiography, 3-Dimensional anatomy.

Functional assessment of atrial wall excursion and foramen ovale flap tracings in 3rd trimester as predictor of short-term hemodynamic stability in congenital heart defects fetuses.

OBJECTIVES: Right atrium and left atrium of the fetal heart play a fundamental role in fetal heart circulatory physiology. METHODS: Excursion of fetal atria walls and tracings of foramen ovale (FO) flap movement were analyzed by M-mode echocardiography by new FO index to determine fetal and neonatal outcome in the first week and month of life in various congenital heart defects. The study group was divided into 3 subgroups: group A: neonates stable after birth (all on I.V. prostaglandin infusion) for at least 7 days, group B: neonates unstable after birth (despite I.V. prostaglandin infusion) requiring catheterization procedure or early cardiac surgery <6th day of life and group C: fetuses with in utero demise. RESULTS: The average values of FO index: group A - 32, group B - 20, group C - 12.Schaffe test showed statistical difference of FO index between group A and B (p=0.029) and group A and C (p=0.001), but no difference between group B and C (p=0.24) The FO index of stability was determined by ROC curve analysis. Cut-off point distinguishing between postnatal stability and postnatal instability + in utero demise constituted FO index=25 (specificity 82%; sensitivity 90%). CONCLUSIONS: Prenatal features of atrial M-mode echocardiography shortly before birth might be helpful to predict the short term prognosis of fetal hemodynamic stability or instability shortly after birth regardless of the type of congenital heart defects (CHD).

Echocardiographic features and outcome of restrictive foramen ovale in fetuses with and without cardiac malformations: Literature review.

Foramen ovale is a small communication between the left and the right atrium and its restriction is a rare congenital heart anomaly. There is no consensus on diagnosis and management of fetal restrictive foramen ovale (RFO). In our paper we included 11 studies about fetuses affected by isolated RFO, RFO with D-Transposition of the Great Arteries (dTGA) and RFO with hypoplastic left heart syndrome (HLHS). While fetuses affected from HLHS and dTGA with RFO have a poor prognosis, premature RFO in an otherwise structurally normal heart, if found in later gestation, have an overall good outcome.

Morphologic and Morphometric Measurements of the Foramen Ovale: Comparing Digitized Measurements Performed on Dried Human Crania With Computed Tomographic Imaging. An Observational Anatomic Study.

The foramen ovale (FO) of the sphenoid bone is clinically important for the interventional treatment of trigeminal neuralgia. Percutaneous procedures applied to treat the chronic pain condition typically involve the cannulation of this oval-like foramen located at the base of the skull. Anatomic variations of the FO have been reported to contribute to difficulties in the cannulation of this structure. Computed tomography (CT) can help the surgeon improve the accuracy and safety of the intervention. However, even with navigation technology, unsuccessful cannulation of the FO has been reported. The aim of this observational anatomic study was to define morphometric and morphologic data of the FO and to investigate for potential differences between measurements taken on dried human crania and digitized measurements of the FO measured on CT images. One hundred eighteen FOs were evaluated. Twenty FOs underwent CT scanning. The mean length of the foramen was 7.41±1.3 mm on the left side and 7.57±1.07 mm on the right. The mean width of the foramen was 4.63±0.86 mm on the left side and 4.33±0.99 on the right. The mean area on the left side was 27.11±7.58 and 25.73±6.64 mm 2 on the right. No significant left-right differences were found for any of these dimensions. The most important conclusion that we can draw is that the measurements can indeed be performed on CT images to obtain an accurate picture of the morphology. Considering the surgical importance of the FO and taking into consideration the limitations this study added to scientific knowledge, this study was constructive as far as neurosurgeons and anatomists are concerned.

Percutaneous Balloon Compression for Treatment of Trigeminal Neuralgia Assisted by O-Arm O2-Based Navigation: Case Series and Review of the Literature.

BACKGROUND: Percutaneous cannulation of foramen ovale (FO) for treatment of trigeminal neuralgia, classically performed according to empirical landmarks and under fluoroscopic guide, may be difficult, time-consuming, and burdened with vascular or neurological complications related to close anatomic relationships. OBJECTIVE: To investigate cannulation of FO for treatment of trigeminal neuralgia assisted by O-Arm O2-based navigation, to assess safety and accuracy. METHODS: Nineteen patients underwent percutaneous balloon compression of Gasserian ganglion assisted by navigation provided by O-Arm O2 and StealthStation. Clinical outcomes according to Barrow Neurological Institute Pain Score, time of recurrence, side effects, and complications, as well as technical aspects as time of the procedure and number of tracks were investigated and evaluated. Obtained data were compared with current literature in a systematic review. RESULTS: The median time for procedure was 46 minutes; cannulation of the FO was performed in a median of 3 minutes and 47 seconds, in a single track in 16 patients, while 3 cases required a further O-Arm acquisition to check the needle position. No complications were observed. Onset of facial hypoesthesia was recorded in 10 patients and dysesthesia in 5. Although at a median follow-up of 12.7 months 7 patients had recurrence after an average pain-free period of 7.3 months, all but 2 patients had improvement in pain score. CONCLUSION: Advantages powered by navigation should be addressed in accuracy, lower complication rate, and success of cannulation even in case of previous treatments or anatomic variations, rather than in effective reduction of surgical time.

Presurgical video-EEG monitoring with foramen ovale and epidural peg electrodes: a 25-year perspective.

BACKGROUND: Epilepsy surgery cases are becoming more complex and increasingly require invasive video-EEG monitoring (VEM) with intracranial subdural or intracerebral electrodes, exposing patients to substantial risks. We assessed the utility and safety of using foramen ovale (FO) and epidural peg electrodes (FOP) as a next step diagnostic approach following scalp VEM. METHODS: We analyzed clinical, electrophysiological, and imaging characteristics of 180 consecutive patients that underwent FOP VEM between 1996 and 2021. Multivariate logistic regression was used to assess predictors of clinical and electrophysiological outcomes. RESULTS: FOP VEM allowed for immediate resection recommendation in 36 patients (20.0%) and excluded this option in 85 (47.2%). Fifty-nine (32.8%) patients required additional invasive EEG investigations; however, only eight with bilateral recordings. FOP VEM identified the ictal onset in 137 patients, compared to 96 during prior scalp VEM, p = .004. Predictors for determination of ictal onset were temporal lobe epilepsy (OR 2.9, p = .03) and lesional imaging (OR 3.1, p = .01). Predictors for surgery recommendation were temporal lobe epilepsy (OR 6.8, p < .001), FO seizure onset (OR 6.1, p = .002), and unilateral interictal epileptic activity (OR 3.8, p = .02). One-year postsurgical seizure freedom (53.3% of patients) was predicted by FO ictal onset (OR 5.8, p = .01). Two patients experienced intracerebral bleeding without persisting neurologic sequelae. CONCLUSION: FOP VEM adds clinically significant electrophysiological information leading to treatment decisions in two-thirds of cases with a good benefit-risk profile. Predictors identified for electrophysiological and clinical outcome can assist in optimally selecting patients for this safe diagnostic approach.

Percutaneous balloon compression for trigeminal neuralgia: a how I do it.

BACKGROUND: Surgical treatments for trigeminal neuralgia may include percutaneous techniques including the balloon compression technique. We present here a simple, effective, and safe adaptation of the historical technique described by Mullan in 1978. METHOD: Our procedure is performed in a bi-plane neuro-radiology room. During general anesthesia, 14-G needle is guided under radioscopy to foramen ovale. The 3-F embolectomy catheter is then inserted and inflated with contrast for a period of 2 min 15 s. CONCLUSION: Our technique, performed entirely under bi-plane fluoroscopy, allows a quicker and more precise surgery and avoids errors in guiding the catheter that can result serious injury.

FORAMEN OVALE AND FORAMEN ROTUNDUM: CHARACTERIZATION OF POSTNATAL DEVELOPMENT.

The sphenoid bone development occurs in both prenatal and postnatal periods. Sphenoid bone openings are used as surgical landmarks and are of great importance for neurosurgeons in everyday practice. The aim of this study was to identify morphological characteristics, postnatal development and remodeling, as well as clinical aspect of the sphenoid bone openings and to investigate their relationship and difference in size. The macerated sphenoid bones analyzed in this study were scanned by micro-computed tomography. Areas and distance in-between foramen ovale and foramen rotundum were measured. In addition, different shapes of foramen ovale were described. The most common shape of foramen ovale on both sides was oval, followed by the round, almond and elongated shapes. Modest to strong positive correlations between all foramina and age for the whole sample and both subsamples were presented, except for the right foramen rotundum area in the male subsample, which did not show significant correlation with age. Our study revealed changes in postnatal development and anatomy of foramen ovale and foramen rotundum, primarily in the aspects of size and shape, and should contribute to reducing the risk of damage to neurovascular structures during surgical procedures.

A Simple Method for Foramen Ovale Puncture Based on Preoperative Image Simulation in Percutaneous Microcompression of the Trigeminal Ganglion.

BACKGROUND: The classic puncture method of percutaneous microcompression using fluoroscopy might be difficult to precisely locate and visualize the foramen ovale. Various new surgical tools to increase the accuracy of finding the foramen ovale location have been introduced. However, all of these systems require some complicated operating steps and/or advanced devices to complete the work. OBJECTIVE: To describe the use of a simple method for foramen ovale puncture by percutaneous microcompression based on preoperative image simulation. METHODS: Forty-five patients were included in the study. All patients underwent a computed tomography examination. Among them, the simulated preoperative puncture pathway was reconstructed on the basis of computed tomography scan examination for 22 patients. Procedures were performed by 2 surgeons: one experienced surgeon and another young surgeon with surgical qualification. The puncturing time and cumulative radiation exposure dose, from start of the puncturing until reaching the foramen ovale, were recorded. Postoperative pain relief, facial hypoesthesia, masticatory muscle weakness, and other complications were recorded. RESULTS: In all cases, the procedure of cannulation was completed successfully. The puncturing time for both the experienced and young surgeon with the use of preoperative image simulation seemed to be time-saving. The young surgeon had less cumulative radiation exposure with the use of preoperative image simulation. Moreover, the intraoperative puncture pathways were almost consistent with the preoperative simulated images. The rest of the process went smoothly. Short-term outcomes of all the 45 patients were satisfactory. CONCLUSION: Based on our preliminary experience, the preoperative image simulation-guided technique is useful during these cases.

Infratemporal Fossa Vascular Anatomy Pertinent to Percutaneous Access to the Foramen Ovale for Treatment of Trigeminal Neuralgia: A Comparison of Cadaveric Dissection and Computed Tomography Analysis.

BACKGROUND: Trigeminal neuralgia may be treated via percutaneous access to the foramen ovale (FO). Vascular complications associated with the needle trajectory can result in serious morbidity and mortality. This study aimed to correlate the vascular relationships of the FO at the skull base via cadaveric dissections and computed tomography (CT). METHODS: Two fresh cadaver heads were injected with red and blue latex to delineate arteries and veins. Neck and infratemporal fossa dissections were carried out to delineate the vascular relationships of the FO. High-resolution head CT images of adult patients undergoing neurosurgical evaluations or procedures were analyzed for distances and sizes of skull base foramina in the infratemporal fossa. RESULTS: Three infratemporal fossa dissections (2 cadaveric specimens) were performed. Mean distance of FO to internal carotid artery was 2.4 ± 0.12 cm, and mean distance of FO to middle meningeal artery was 0.8 ± 0.16 cm. Head CT images of 52 patients (104 sides) with 1-mm axial slice thickness were analyzed. Area of the FO was 31.1 ± 9.6 mm2. Distance of FO to internal carotid artery was 1.70 ± 0.31 cm, and distance of FO to middle meningeal artery was 0.73 ± 0.61 cm. CONCLUSIONS: Cadaveric delineation of vascular structures in the infratemporal fossa correlates with head CT imaging and may be used to accurately plan percutaneous access to the FO. Inadvertent puncture of the extracranial internal carotid artery is nearly impossible with good technique. The most likely source of percutaneous vascular injury is the middle meningeal artery and distal branches of the maxillary artery.

Clinical features and echocardiographic findings of isolated foramen ovale restriction in foetuses.

Isolated restrictive foramen ovale (rFO) without complex heart defects is a rare pathology. There may be difficulties in managing this situation, which can lead to right heart enlargement, tricuspid regurgitation and hydrops findings in the foetus. We conducted a retrospective analysis of 8451 foetuses. 7883 (93.2%) had a structurally normal heart or minor heart disease, 18 (0.22%) of which had a diagnosis of isolated rFO. Nine patients with neonatal echocardiographic examination were included in the study. In 8 (88.8%) patients, it was stated that a decision to give birth should be made at the time of presentation. Evaluating postpartum echocardiographic examinations, 7 (77.7%) patients had normal or minor defects. The decision of delivery made at the right time during follow-up is critical to determine the prognosis.IMPACT STATEMENTWhat is already known on this subject? The data about the prenatal diagnosis of isolated rFO is limited.What the results of this study add? We conducted a retrospective analysis of 8451 foetuses. 7883 (93.2%) foetuses had a structurally normal heart or minor heart disease, 18 (0.22%) of which had a diagnosis of rFO. Nine patients with foetal and postnatal follow-up and echocardiographic findings were examined in the study. The group's median gestational age at admission was 35.0 weeks (range: 27.0-39.0 weeks). The delivery decision was made in 8 (88.8%) patients at the time of admission. Evaluating postpartum echocardiographic examinations, 7 (77.7%) patients had normal or minor defects. Additionally, one patient was diagnosed with cardiomyopathy, and the other patient was diagnosed with functional pulmonary atresia. No death occurred in any foetus during follow-up.What the implications are of these findings for clinical practice and/or further research? Isolated rFO, a rare condition in the foetus, is generally well-tolerated in foetal life. However, the right heart enlargement, tricuspid regurgitation, or hydrops findings can be seen in patients. The decision of delivery made at the right time during follow-up is critical to determine the prognosis.

Hypoplastic left heart syndrome with prenatally diagnosed foramen ovale restriction: diagnosis, management and outcome.

OBJECTIVE: Despite advances in prenatal diagnosis and postnatal intervention/surgery methods, patients with Hypoplastic Left Heart Syndrome (HLHS) and coexisting foramen oval restriction still achieve high mortality rates. Our objective was to determine survival predictors and to find answers to, why restriction develops in some, but not others. METHODS: We performed a retrospective analysis of prenatal history and postnatal sequel of 22 patients with HLHS and foramen ovale restriction between 2008 and 2017. RESULTS: There were 11 survivors and 11 nonsurvivors. The most significant difference between the two groups pertained to the average time of foramen ovale restriction diagnosis which was 33 weeks for survivors and 28 weeks for nonsurvivors (p = .0416) and the duration of in-utero restriction (9 versus 5 weeks, p = .0213). Twenty patients (20/22) exhibited possible signs of infection. CONCLUSIONS: (1) Earlier development and longer presence of foramen ovale restriction in the setting of HLHS is associated with higher short-term mortality regardless of the degree of restriction. (2) Ratio of forward pulmonary vein flow to reverse flow (f/r) expressed as a velocity-time integral (VTI) is a good emergent intervention predictor, but it does not correlate with foramen ovale size and maximal velocity, nor does it influence survival rates. (3) Ultrasonographic signs of possible infection of the fetus is a potential risk factor of foramen ovale restriction development in patients with HLHS.

A Segmentation Method of Foramen Ovale Based on Multiatlas.

Trigeminal neuralgia is a neurological disease. It is often treated by puncturing the trigeminal nerve through the skin and the oval foramen of the skull to selectively destroy the pain nerve. The process of puncture operation is difficult because the morphology of the foramen ovale in the skull base is varied and the surrounding anatomical structure is complex. Computer-aided puncture guidance technology is extremely valuable for the treatment of trigeminal neuralgia. Computer-aided guidance can help doctors determine the puncture target by accurately locating the foramen ovale in the skull base. Foramen ovale segmentation is a prerequisite for locating but is a tedious and error-prone task if done manually. In this paper, we present an image segmentation solution based on the multiatlas method that automatically segments the foramen ovale. We developed a data set of 30 CT scans containing 20 foramen ovale atlas and 10 CT scans for testing. Our approach can perform foramen ovale segmentation in puncture operation scenarios based solely on limited data. We propose to utilize this method as an enabler in clinical work.