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Purpose: The vertebral artery (VA) pierces the dura mater and continues with the intradural V4 segment. Once entered into the dura mater, the VA ascends from the infero-lateral to the antero-superior side of the medulla. Scarce reports of VAs compressing the medullospinal junction (MSJ) are available. We therefore aimed to determine the incidence of a course of the AV over the MSJ. Method: One hundred sixty-two archived CT angiogram files were documented in the study. We recorded the cases in which the VA crossed the MSJ. We assessed the VA as dominant, non-dominant or co-dominant. Results: In 32 cases (19.75%), we identified intradural AVs on the ventral side of the MSJs. The incidence of this course of the VA was 17.1% in males and 23.81% in females. Of the 32 cases, the VA was non-dominant in 6, dominant in 14, and co-dominant in 12. Conclusion: The VA course over the MSJ is not rare. Therefore, when specific neurological signs of MSJ or medulla compression are found, the course of the VA should be documented on CT or MRI angiograms. [ABSTRACT FROM AUTHOR]

Background: Dural arteriovenous fistulas (dAVFs) in the foramen magnum region (FMR) are rare entity of dAVFs. There is no established treatment for FMR-dAVFs owing to their rarity and anatomical complexity. Herein, we report cases of high-flow dAVFs located at the posteromedial part of the FMR that were successfully treated by surgical interruption. Methods: We demonstrated the surgical procedures for the interruption of high-flow FMR-dAVF with representative images and videos. In both cases, endovascular transarterial embolization was performed prior to surgical interruption. Conclusion: As this type of FMR-dAVF has high-risk clinical features, curative surgical treatment is highly desirable. [ABSTRACT FROM AUTHOR]

The editorial discusses the challenges of reimbursement for 3D printing in United States Health Care Facilities (HCFs) due to operating expenses exceeding collections. It proposes new technology Ambulatory Payment Classification (APC) codes to fairly reimburse 3D printing services based on technical complexity levels. A survey conducted by the American College of Radiology revealed widespread use of 3D printing in US healthcare, with various specialties utilizing patient-specific 3D printed parts. The editorial recommends categorizing 3D printing complexity into Basic, Intermediate, and Complex levels to guide reimbursement and ensure appropriate use of resources. [Extracted from the article]

Objective: Posterior fossa decompression for Chiari malformation type I (Chiari 1) is effective and associated with a low risk of complication. However, up to 20% of patients may experience continued deficits or recurring symptoms after surgical intervention. For pediatric patients, there are no established tools to predict outcomes, and the risk factors for unfavorable postoperative outcomes are poorly understood. Hence, our aim was to investigate baseline data and early postoperative predictors of poor outcomes as determined by the Chicago Chiari outcome scale (CCOS). Methods: All pediatric patients (< 18 years) receiving a posterior fossa decompression for Chiari 1 between the years of 2005 and 2020 at the study center were eligible for inclusion. Patients with congenital anomalies were excluded. Results: Seventy-one pediatric patients with a median age of 9 years were included. Most patients (58%) were females. Chiari 1 was associated with syringomyelia (51%), scoliosis (37%), and hydrocephalus (7%). Perioperative complications occurred in 13 patients (18%) of which two required additional procedures under general anesthesia. On multivariable proportional odds logistic regression, motor deficits (OR: 0.09; CI95%: [0.01–0.62]; p = 0.015), and surgical complications (OR: 0.16; CI95%: [0.41–0.66]; p = 0.011) were significant predictors of worse outcomes. The presence of syringomyelia was identified as a predictor of better outcomes (OR: 4.42 CI95% [1.02–19.35]; p = 0.048). A persistent hydrocephalus during the early postoperative period after posterior fossa decompression was a strong predictor of worse long-term CCOS (OR: 0.026; CI95%: [0.002–0.328]; p = 0.005). Conclusion: Results from this study indicate that the existence of motor deficits and syringomyelia prior to surgery, and surgical complications and persistent hydrocephalus despite posterior fossa decompression, were useful predictors of long-term outcome. [ABSTRACT FROM AUTHOR]

To evaluate the effect of the basilar invagination (BI) type B on cervical spine. The research protocol used head magnetic resonance imaging (MRI) exams from 41 participants with BI type B and 158 controls. The criterion for BI was the distance of the odontoid apex to Chamberlain's line (DOCL) equal to or greater than 7 mm. The clivus length (CLI), clivus canal angle (CCA), Welcker's basal angle (WBA), Boogaard's angle (BOA), upper cervical lordosis angle (UCL), and total cervical lordosis angle (CL) were evaluated. The descriptive analysis, group comparisons, and correlations between skull base and cervical spine parameters were performed at the 95% CI. Participants with BI type B showed shorter clivus length (CLI: 25.7 ± 7.3 mm); greater angulation of the skull base (WBA: 126.5 ± 10.4); greater inclination foramen magnum (BOA: 151.5 ± 14.5); decrease in the value of the CCA (131.6 ± 15); and greater angulations of UCL (17.9 ± 13.8) and CL (29.7 ± 19.9) in comparison to the control group (P < 0.05). Clivus length and CCA correlated inversely with UCL and CL, while BOA correlated directly with UCL and CL. The WBA did not correlate with CL (P < 0.05). The deformation of skull base in the BI of type B caused, on average, a hyperlordosis of almost 30° in the C2-C6 segment. This change was approximately 17° in the C2-C4, with the clivus hypoplasia being a risk factor for cervical hyperlordosis. [ABSTRACT FROM AUTHOR]

Background: The management for craniocervical junction dural arteriovenous fistulas (CCJ-DAVFs) remains controversial and clinically challenging. We systemically summarized the clinical and angiographic outcomes of microsurgery, embolization, and conservative management. Methods: Relevant articles were retrieved from PubMed, Scopus, Web of Science, and Cochrane, following PRISMA guidelines. A systematic review and meta-analysis were conducted on the clinical characteristics, management approaches, and clinical and angiographic outcomes. Results: We included 13 articles (166 patients). The weighted mean age was 58.9 years (95%CI: 53.2–64.5), 58.8 years (95%CI: 48.4–69.2), and 63.8 years (95%CI: 60.1–67.5), in microsurgery, embolization, and conservative groups respectively, with an overall male sex predominance (microsurgery [n = 51/77, 66.2%], embolization [n = 44/56, 78.6%], and conservative management [n = 6/8, 75.0%]). Patients were managed with microsurgery (n = 80/172, 46.5%), embolization (n = 79/172, 45.9%), and conservative treatment (n = 13/172, 7.6%). Foramen magnum was the most common location (microsurgery [n = 34/77, 44.2%], embolization [n = 31/56, 55.4%], and conservative treatment [n = 3/8, 37.5%]). Vertebral artery was the primary feeder (microsurgery [n = 58/84, 69.1%], embolization [n = 41/86, 47.6%], and conservative treatment [n = 4/7, 57.1%]). Complete fistula obliteration rates were 74.1% (95%CI:52.3–88.2%) in the microsurgery group and 54.9% (95%CI:30.7–77.0%) in the embolization group. Complications rates were 16.2% (95%CI:6.7–34.5%) in the embolization group, 11.6% (95%CI:3.8–30.4%) in the microsurgery group, and 7.7% (95%CI:1.1–39.1%) in the conservative group. Different rates of good clinical outcomes were observed [microsurgery: 66.4% (95%CI:48.1–80.8%), embolization: 51.9% (95%CI:30.8–72.4%), and conservative: 11.6% (95%CI:4.4–27.4%)]. Conclusions: In patients with CCJ-DAVFs, each management approach has its own merits based on the fistula and patient characteristics. [ABSTRACT FROM AUTHOR]

Background: The shape and morphology of the foramen magnum play a crucial role in identifying the cause and formulating the treatment approach for neurological conditions such as Arnold Chiari malformation. Transcondylar approach enables neurosurgeons to access the brainstem and cervico medullary junction region with minimum retraction and it requires thorough knowledge of different parameters of foramen magnum. Aim: To study the morphometric characteristics of foramen magnum in dry human skulls. Material and method: This study was conducted on hundred skulls, obtained from Department of Anatomy from various teaching Institutions of Mumbai. Result: Most common shape of foramen magnum found in this study was oval shape followed by tetragonal shape. The mean Anterior-Posterior Diameter (APD) and Transverse Diameter (TD) of foramen magnum calculated were 33.8 ± 3.5 mm and 28.8 ± 3.1 mm respectively. Fifty-five skulls (out of hundred) were having FM index more than 1.2, while forty-five skulls (out of hundred) were having FM index less than or equal to 1.2. Mean of foramen magnum areas calculated by method of Routalet al and by Teixeira's method were 770.56 ± 143.06 mm2 and 777.83 ± 143.77 mm2 respectively. Conclusion: The data collected in this study will be valuable for neurosurgeons in examining the Craniovertebral junction's anatomy for preoperative planning and skull base surgery management. These results will also provide insights for Radiologists, Orthopedicians, Anthropologists, Anatomists, anesthesiologist and forensic specialists. [ABSTRACT FROM AUTHOR]

C-type natriuretic peptide (CNP), a member of the natriuretic peptide family, is a potent endochondral bone growth factor that exerts its biological effects via the guanylate cyclase B (GC-B) receptor. We previously demonstrated that CNP knockout (KO) mice exhibited midfacial hypoplasia along the sagittal plane; however, the effects of GC-B (the receptor for CNP) on endochondral ossification in the maxillofacial region remain unclear, and the mechanism of the CNP/GC-B system has not been elucidated. We investigated the physiological significance of GC-B in the cartilage of the craniofacial region through analysis of cartilage-specific GC-B KO mice. Morphological assessments were performed at 12 weeks old, with histological analyses performed at 2 weeks old. GC-B-KO mice exhibited sagittal midfacial hypoplasia, foramen magnum stenosis, and spinal canal stenosis. Histological examination revealed reduced thickness in the spheno-occipital synchondrosis (SOS), a critical growth center in cranio-maxillofacial skeletal development. The hypertrophic zone of the SOS exhibited reduced thickness, accompanied by a reduction in cell count in this area. This study highlights the essential role of GC-B receptors in craniofacial morphology contributing to our understanding of the mechanisms underlying facial morphological abnormalities, foramen magnum stenosis, and spinal canal stenosis. [ABSTRACT FROM AUTHOR]

Chiari I malformation (CM-I) is defined as the extension of brain tissue into the spinal cord. This study aimed to refine the methodology for the acquisition of 3-dimensional measurements of the posterior fossa and introduce occipital keel size as a new marker and its impact in patients with CM. In this retrospective study, all patients who underwent Chiari decompression surgery at Montefiore Medical Center from April 2012 to April 2022 were included. Perioperative clinical information was obtained in addition to maximal keel thickness (KT), foramen magnum area, and preoperative and postoperative posterior fossa volumes for each patient and age-matched controls. Volumetric measurements were obtained using artificial intelligence-based semiautomated segmentation. A total of 107 patients with CM including 37 males, and 70 females were studied with a mean age of 26.56 ± 17.31 compared with 103 controls without CM. The comparison between the CM and the general population groups demonstrated a significantly increased keel size in Chiari patients. Keel size had a significant relationship with dysphagia, paresthesia, and intraoperative blood loss, while posterior volume change had a significant relationship with sex and early symptomatic improvement. The Foramen magnum area was related to tonsillar descent and more prominent in patients with spina bifida. The Keel of Goodrich is a new anatomical factor that should be taken into consideration when evaluating preoperative symptoms, and intraoperative complications in patients with CM-I. Volumetric analyses demonstrated that posterior fossa volume change had a significant impact on early symptom improvement in patients with Chiari, as did the choice of operative approach. The routine use of semiautomated segmentation of the posterior fossa may help stratify Chiari patients in the future and should be implemented in routine clinical care. [ABSTRACT FROM AUTHOR]

Background Symptomatic cerebellar cyst formation after surgery is rare and the mechanism remains unknown. We describe a cerebellar cyst that gradually expanded, becoming symptomatic, after the removal of a foramen magnum meningioma and discuss the mechanism of cyst formation. Case Description A 76-year-old woman with a tumor at the foramen magnum was treated by posterior fossa craniotomy and C1 hemilaminectomy. The patient suddenly developed cerebellar symptoms and consciousness disturbance approximately 1 week into an otherwise good postoperative course. Imaging showed a subcutaneous pseudomeningocele in the occipital region and cerebellar cyst formation. After resolution by fenestration of the cerebellar cyst and duraplasty, the patient's symptoms gradually improved. No tumor or cerebellar cyst recurrence has been detected in over 5 years since the surgery. Conclusion Postoperative pseudomeningocele appeared crucial for cerebellar cyst formation. Postoperative development of symptomatic cerebellar cysts is rare but should be recognized as a serious, sometimes life-threatening, postoperative complication of posterior fossa surgery. [ABSTRACT FROM AUTHOR]

Background and Objectives: Typically, the vertebral arteries (VAs) enter the posterior fossa through dural rings and further unite, forming the basilar artery. The posterior inferior cerebellar artery (PICA) is usually a branch of the V4 segment of the VA (intradural origin). It may also leave the V3 suboccipital segment of the VA (extradural origin). The transdural origin of the PICA within the VA's dural ring has been consistently overlooked. A study was designed to determine the topographical patterns of the PICA's origin. Materials and Methods: Determinations were performed in a retrospective sample of 225 computed tomography angiograms. Four types of PICA origin were documented: type 0, absent PICA; type 1, the extradural origin of the PICA from the V3 segment of the VA; type 2, the transdural origin of the PICA within the dural ring; and type 3, the intradural origin of the PICA from the V4 segment of the VA. The bilateral symmetry of types was also investigated. Results: Out of 450 VAs, type 0 (absent PICA) was found in 36%, type 1 (extradural) in 0.44%, type 2 (transdural) in 5.56%, and typical type 3 in just 58%. In types 1 and 2, the PICA entered the posterior fossa through the dural ring and the marginal sinus. In the overall group (N = 225), the type combinations 1_1, 1_2 and 1_3 were not found. Bilaterally absent PICAs occurred in 18.67%. The bilateral combinations 0_1/0_2/0_3/2_2/2_3/3_3 were found, respectively, in 0.89%/3.11%/30.67%/1.78%/4.44%/40.44%. Four of the seventy-eight PICAs opposite to an absent one, three intradural and one transdural, were true bihemispheric PICAs. Conclusions: The PICAs with extradural or transdural origins are facultative contents of the dural ring and are at risk during neurosurgical approaches in the foramen magnum. Rare bihemispheric PICAs could originate either intradurally or within the dural ring. [ABSTRACT FROM AUTHOR]

Background. This study aims to evaluate the accuracy rate of foramen magnum dimensions in determining sex among the South Indian population using discriminant functional analysis. Methods. An observational study in which CBCT images from 200 full field of view (FOV) scans were analysed. The dimensions of the foramen magnum were measured. Intra‐ and interobserver reliability were calculated. Independent t‐tests were used to compare the various parameters between sexes. Stepwise discriminant function analysis was used to determine sex. Results. A total of 200 CBCT scans were included in the study. The mean age (±SD) was 25.66 (±7.11) years among males and 24.64 (±5.12) years among females. The measurements and the circumference of the foramen magnum were significantly (p < 0.001) greater in males than in females. The univariate analysis of foramen magnum measurements reached an accuracy rate of 73.5% in sex determination. The discriminant function analysis combining the foramen magnum measurements and circumference yielded an overall predictability rate of 66.5% for determining sex. Conclusion. Taking into account the predictability rate of sex based on foramen measurement in the present population, it can be concluded that its applicability should be limited to cases associated with fragmentary skull bases. [ABSTRACT FROM AUTHOR]

Background: Chiari I malformation (CMI) is characterized by inferior descent of the cerebellar tonsils through the foramen magnum and is associated with headache and neck pain. Many morphometric research efforts have aimed to describe CMI anatomy in the midsagittal plane using classical measurement techniques such as linear dimensions and angles. These methods are less frequently applied to parasagittal features and may fall short in quantifying more intricate anatomy with fewer distinct homologous landmarks. Methods: Landmark-based geometric morphometric techniques were used to asses CMI morphology in five anatomical planes of interest. Results: Significant shape differences between CMI and age/sex-matched controls were found in the midsagittal (Pseudo-F=5.4841, p = 0.001) and axial planes through the rostral medulla (Pseudo-F=7.6319, p=0.001). In addition to tonsillar descent, CMI principal component 1 (PC1) scores in the midsagittal protocol were associated with marked anterior concavity of the brainstem and generalized verticality of the cerebellum with anterior rotation of its anterior lobe. In the axial medulla/cerebellum protocol, CMI PC1 scores were associated with greater anterior-posterior (A-P) dimension with loss of medial-lateral (M-L) dimension. Discussion: These results suggest that CMI is associated with greater curvature of the brainstem and spinal cord, which may perturb normal neural activities and disrupt cerebrospinal fluid movements. Previous reports on the A-P diameter of the posterior fossa in CMI have conflicted; our findings of greater A-P cerebellar dimensionality with concomitant loss of width alludes to the possibility that more caudal aspects of the posterior cranial fossa are more bowl-like (homogenous in axial dimensions) and less trough-like or elongated in the M-L direction. [ABSTRACT FROM AUTHOR]

This document is a letter published in the journal Acta Neuropathologica Communications. It discusses the genetic analysis of foramen magnum meningiomas (FMMs), which are rare tumors that account for approximately 1% of intracranial meningiomas. The study aims to elucidate the genetic profiles of meningiomas at the foramen magnum, a challenging task due to the difficulty in identifying their site of origin. The researchers accurately identified the main feeder of FMMs and performed a genetic analysis, revealing that the AKT1 p.Glu17Lys mutation was the most frequent driver mutation in FMMs, while TRAF7 mutations were absent. The study suggests that FMMs resemble spinal meningiomas more than common intracranial meningiomas in terms of driver mutations. [Extracted from the article]

Background: Foramen magnum (FM) is the largest foramen in the skull. Through foramen magnum cranial cavity communicates with the vertebral canal.Foramen magnum region in different ethnic populations has significant differences between the sexes in their populations. The metric examinations show significantly higher values on male skull bases than on female skull bases. Sexual dimorphism is one of the major areas of interest to anatomists, anthropologists, skeletal biologists, forensic scientists and other specialists. Objectives: To assess computed tomographic based measurements of foramen magnum dimensions in determination of gender and age in Kashmiri population. Methods: A total of 252 (119 males and 133 females) CT skull images ofadult population with individuals age range above skeletal immaturity (age above 20 years) wasdone. Analysis of CT images was done on a PACS workstation monitor along with an experienced radiologist. 3D multi-planar reformation on CT console was done with reformation lines oriented along the lower most points of basion and opisthion (sagittal plane) and the mid-point of cervical spinal canal at C1/C2 level (coronal plane) to get the maximum cross-sectional area of foramen magnum. Results: The mean anteroposterior diameter among males was3.66+0.43cmwhile among females it was 3.55+0.39cm with 95% confidence interval [-0.008 to 0.211]. The association was statistically significant with [p=0.03] and t-value 2.12. The mean transverse diameter was 3.45+0.59cm among males and 3.43+0.65cmamong femaleswith 95%confidence interval [-0.134 to-0.174]. The association was found statistically insignificant with [p=0.79] and t-value 0.25. The mean A.P, transverse, circumference, areaamong>40yearswas3.69+0.58cm, 3.47+0.65cm, 8.04+3.04cmand30.91+3.71cm² respe ctively. Tetragonal, irregular and rounded shape was observed in (12.3%), (8.3%), and (4.8%) cases respectively. Pentagonal and diamond shape was found in 1.6% and 0.4% respectively. Conclusion: Data collected in present investigation could serve as database for the quantitative description of dimensions of foramen magnum during normal growth and development considering sex and ethnic related variations. [ABSTRACT FROM AUTHOR]

Achondroplasia is the most common skeletal dysplasia and is associated with serious complications such as foramen magnum stenosis (FMS). This case report describes an infant with achondroplasia who presented with a syndrome of inappropriate antidiuretic hormone secretion (SIADH), secondary to significant FMS and myelocompression. A 2-month-old boy with prenatally diagnosed achondroplasia was referred due to disordered breathing and altered consciousness. On admission, apathy, hypotonus, and hypothermia with typical features of achondroplasia were noticed. Laboratory investigations revealed severe hyponatremia and hypochloridaemia with normal glucose and urea levels. The diagnosis of SIADH was made based on low serum osmolality in the presence of high urine osmolality, along with an elevated copeptin level. An emergency computerized tomography showed a high-grade stenosis at the cranio-cervical junction; subsequent magnetic resonance imaging demonstrated myelocompression. The patient underwent decompression surgery the next day; serum osmolality increased after the operation. Spontaneous breathing after extubation was sufficient whereas tetraplegia persisted despite intensive physiotherapy. Clinicians should be aware of SIADH as a presenting sign of FMS in children with achondroplasia. Further discussion is warranted regarding improving parental education and timing of screening recommendations. [ABSTRACT FROM AUTHOR]

Foramen magnum decompression (FMD) is an established technique for patients with Chiari-1 malformation. However, the extent of decompressive surgery is controversial, in particular whether dural opening is undertaken. In this study, we report outcomes with our technique utilising intraoperative ultrasound (iOU) findings. Decision to proceed for further decompression was based on CSF flow around foramen magnum and visualisation of tip of tonsils. Review of adults with CM-1 undergoing FMD 2013–2018. Patients underwent a suboccipital craniectomy ± partial C1 superior laminectomy ± duraplasty in a stepwise manner. Favourable iOU findings of CSF flow around the foramen magnum and pulsation of the tonsillar tips were sought at each step. Post-operative outcomes were assessed using the Chicago Chiari Outcome Score (CCOS). Fifty-seven patients were included. The mean age was 47 years (range 18–77 years). There was a strong female preponderance (48 females to nine males). The mean follow-up was 3.2 years (range 1–5 years). Surgery included: suboccipital craniectomy (52/57, 91%), plus partial C1 superior laminectomy (2/57, 4%), and plus duraplasty (3/57, 6%). Redo surgery was undertaken in 7/57 patients (12%). At final follow-up, 56/57 (98%) patients achieved a good (CCOS 13–16) or satisfactory (CCOS 9–12) outcome based on COSS. A patient centred approach to surgery utilising findings from iOU can achieve favourable outcomes. Dural opening is not routinely required. [ABSTRACT FROM AUTHOR]

Objective While the transcondylar approach is technically challenging, it provides generous ventral and caudal exposure to the craniovertebral junction. This approach requires navigation around multiple eloquent neurovascular structures including the lower cranial nerves, vertebral artery and its branches, and the brainstem. Superficial exposure, including incision location and muscle dissection, can dramatically affect the surgical angle and maneuverability at depth. Methods We demonstrate the transcondylar approach in a step-by-step fashion in a formalin-embalmed, latex-injected cadaver head. Dissection within each layer of the suboccipital muscles was performed. A small cohort with an illustrative case is also included herein. Results The sternocleidomastoid (SCM) muscle was retracted anteriorly; the splenium capitis, semispinalis capitis, and longissimus capitis muscles were disconnected from the superior nuchal line and reflected inferomedially. The suboccipital muscle group was fully exposed. The superior and inferior oblique muscles were disconnected from the transverse process of C1. The superior oblique and the rectus capitis posterior major muscles were then dissected off the inferior nuchal line, and the suboccipital muscle group was retracted inferomedially en bloc. The greater auricular nerve was retracted laterally with the SCM, and the greater occipital nerve was retracted inferomedially with the suboccipital muscle group. Conclusion This technique avoids the obstructive muscle bulk that results from a myocutaneous approach while maximizing deep exposure. Understanding the detailed muscular anatomical relationship with the insertion location and suboccipital nerves is key to complete and safe extracranial dissection. Diligent dissection helps minimize postoperative pain and muscle spasm while optimizing the closure technique. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Due to the young age of children, the occipital condyle and foramen magnum are not fully developed, and they are prone to various diseases and injuries in the occipitocervical junction, which requires surgical treatment in severe cases. However, anatomical parameters for the development of the occipital condyle and foramen magnum in children are lacking. OBJECTIVE: To measure the morphological structure of the occipital condyle and foramen magnum by three-dimensional reconstruction technique, and to provide important anatomical parameters for occipitocervical junction lesions, related surgical procedures and forensic identification. METHODS: Imaging data of 389 cases of primitive children and adolescents involved in skull base undergoing spiral CT scanning (247 males and 142 females) aged 1-18 years were collected and divided into 1-3-year-old group, 4-6-year-old group, 7-9-year-old group, 10-12-year-old group, 13-15-year-old group, and 16-18-year-old group according to their age. Mimics 16.0 software was used to reconstruct the skull base and measure the length and width of the foramen magnum. A formula was used to calculate the area and index of the foramen magnum. We measured the length, width and height of the occipital condyle, the angle between the long axis and the sagittal axis of the occipital condyle (O-S angle), the included angle between the midpoint of the front and back edges of the foramen magnum and the connection between the back edge of occipital condyle and the intersection point of the foramen magnum (F-O angle), and the included angle between the midpoint of the front and back edges of the foramen magnum and the midpoint of the back wall of the sublingual neural tube (F-H angle). Gender, side and age differences were analyzed among the indicators. RESULTS AND CONCLUSION: (1) In foramen magnum measurement, there was no significant difference between sexes in the index of the foramen magnum (P > 0.05), but there were significant differences in length, width and area of the foramen magnum (P < 0.05). (2) The O-S angle, F-O angle and F-H angle of the occipitral condyle were not significantly different between genders (P > 0.05), but length, width and height of the occipital condyle were significantly different between genders (P < 0.05). (3) There were no significant differences in the length of the occipital condyle among different groups (P > 0.05), but there were significant differences in the width and height of the occipital condyle, O-S angle, F-O angle and F-H angle among different groups (P < 0.05). (4) Length, width and area of the foramen magnum, length, width and height of the occipital condyle showed a wavy increasing trend with the increase of age, while O-S, F-O and F-H angles showed a wavy decreasing trend with the increase of age, while the index of the foramen magnum showed no significant change. (5) In conclusion, there are gender and lateral differences in the morphological indexes of the foramen magnum and the occipital condyle in children. These differences can provide an important reference for clinical surgical approach selection and forensic examination. [ABSTRACT FROM AUTHOR]

Meningiomas are common in the foramen magnum area. Due to its slow growing, the patient may be asymptomatic for a long time, and the tumor is often large in size at the time of discovery. Due to the narrow space in the foramen magnum area and the involvement of important structures such as the brain stem, the lower cranial nerves, and vertebral arteries, surgery for meningiomas in the foramen magnum area remains a technical challenge, especially the ventral foramen magnum meningiomas(vFMs). Due to the obstruction of the medulla oblongata, the cervical spinal cord, the vertebral artery and the the lower cranial nerves, exposure and removal of vFMs is extremely difficult. Sufficient revealing the base of vFMs is decisive factor of the operation, the far lateral approach is considered the first choice for removal of vFMs. However, the far lateral approach has the disadvantages of complicated craniotomy, time-consuming, severe muscle damage, and high risk of vertebral artery injury. In clinical practice, most vFMs pushed the medulla oblongata and the cervical spine to one side due to their own space-occupying effect, forming a natural tumor channel. Using this channel and posterior suboccipital approach, the author successfully removed 19 cases of ventral meningiomas in the foramen magnum area. The posterior suboccipital approach is an easy and quick approach and ideal for the majority of vFMs. [ABSTRACT FROM AUTHOR]

Changes in gene regulatory elements play critical roles in human phenotypic divergence. However, identifying the base-pair changes responsible for the distinctive morphology of Homo sapiens remains challenging. Here, we report a noncoding single-nucleotide polymorphism (SNP), rs41298798, as a potential causal variant contributing to the morphology of the skull base and vertebral structures found in Homo sapiens. Screening for differentially regulated genes between Homo sapiens and extinct relatives revealed 13 candidate genes associated with basicranial development, with TBX1 , implicated in DiGeorge syndrome, playing a pivotal role. Epigenetic markers and in silico analyses prioritized rs41298798 within a TBX1 intron for functional validation. CRISPR editing revealed that the 41-base-pair region surrounding rs41298798 modulates gene expression at 22q11.21. The derived allele of rs41298798 acts as an allele-specific enhancer mediated by E2F1, resulting in increased TBX1 expression levels compared to the ancestral allele. Tbx1 -knockout mice exhibited skull base and vertebral abnormalities similar to those seen in DiGeorge syndrome. Phenotypic differences associated with TBX1 deficiency are observed between Homo sapiens and Neanderthals (Homo neanderthalensis). In conclusion, the regulatory divergence of TBX1 contributes to the formation of skull base and vertebral structures found in Homo sapiens. [Display omitted] Changes in gene regulatory elements are crucial for human phenotypic divergence. However, identifying the changes responsible for the distinct morphology of Homo sapiens remains challenging. Here, we report a noncoding SNP, rs41298798, in TBX1 as a potential causal variant contributing to the basicranial morphology found in Homo sapiens. [ABSTRACT FROM AUTHOR]

This article presents a comparative study on the anatomical assessment of the foramen magnum (FM) among the South Indian population using CT scans. The study found that the most common shape of the FM in both dry skulls and CT scan images was hexagonal. There were no significant differences in measurements between the two methods. The study provides valuable information for surgeons and medical professionals. The document is a list of references to various studies and articles related to the anatomical assessment of the foramen magnum and spinal cord, which can be useful for researchers studying these features in different populations. [Extracted from the article]

Purpose: Proximity to critical neurovascular structures can create significant obstacles during surgical resection of foramen magnum meningiomas (FMMs) to the detriment of treatment outcomes. We propose a new classification that defines the tumor's relationship to neurovascular structures and assess correlation with postoperative outcomes. Methods: In this retrospective review, 41 consecutive patients underwent primary resection of FMMs through a far lateral approach. Groups defined based on tumor-neurovascular bundle configuration included Type 1, bundle ventral to tumor; Type 2a-c, bundle superior, inferior, or splayed, respectively; Type 3, bundle dorsal; and Type 4, nerves and/or vertebral artery encased by tumor. Results: The 41 patients (range 29–81 years old) had maximal tumor diameter averaging 30.1 mm (range 12.7–56 mm). Preoperatively, 17 (41%) patients had cranial nerve (CN) dysfunction, 12 (29%) had motor weakness and/or myelopathy, and 9 (22%) had sensory deficits. Tumor type was relevant to surgical outcomes: specifically, Type 4 demonstrated lower rates of gross total resection (65%) and worse immediate postoperative CN outcomes. Long-term findings showed Types 2, 3, and 4 demonstrated higher rates of permanent cranial neuropathy. Although patients with Type 4 tumors had overall higher ICU and hospital length of stay, there was no difference in tumor configuration and rates of postoperative complications or 30-day readmission. Conclusion: The four main types of FMMs in this proposed classification reflected a gradual increase in surgical difficulty and worse outcomes. Further studies are warranted in larger cohorts to confirm its reliability in predicting postoperative outcomes and possibly directing management decisions. [ABSTRACT FROM AUTHOR]

Objective: Many acupuncture acupoints are located on the posterior midline of the neck region. The needling depth for acupuncture is important for practitioners, and an unsafe needling depth increases the possibility of damage to the spinal cord and brainstem. Can the safety of acupuncture be assessed by examining bone structures? We focused on this aim to carry out this study. Methods: The shortest distance from the posterior border of the foramen magnum to the line joining both upper ends of the posterior border of the mastoid process was measured on 29 skulls. Distances from the posterior border of the vertebral foramen to the tip of the spinous process and posterior tubercle of the atlas were measured and evaluated from 197 dry cervical vertebrae and 31 lateral cervical radiographs of patient subjects. The anatomic relationships of the vertebral canal with the external occipital protuberance, tip of the spinous process of the axis, tip of the posterior tubercle of the atlas, and upper end of the posterior border of the mastoid process were observed and evaluated via lateral cervical radiography. Results: The shortest distance from the foramen magnum to the line between the mastoid processes was 4.65±1.75 mm, and the distance from the superior border of the vertebral foramen of the atlas to the posterior tubercle was less than the distance from the inferior border. The distance from the superior border of the vertebral canal to the tip of the spinous process in C2-C7 was greater than the distance from the inferior border. The mean lengths of the superior border of the C2 spinous process and the inferior border of the C7 spinous process were greater than 21 mm and 31 mm, respectively. The line from the upper end of the posterior border of the mastoid process to the tip of the C2 spinous process or 10 mm deep to the tip of the C2 spinous process was posterior to the vertebral canal. Conclusions: On the posterior midline of the neck region between the tip of spinous process of axis and external occipital protuberance, if the needle reaches the depth of the line between the upper end of posterior border of mastoid process and the tip of the spinous process of the axis, approximately 10 mm along the spinous process of the axis, the needle is in the safe region. The mean length of the C2-C7 spinous process is suitable to accommodate the needling depth of the adjacent acupoint. Bone structures can be used to effectively assess the safety of acupuncture on the posterior midline of the neck region. [ABSTRACT FROM AUTHOR]

AbstractBackground and ImportanceClinical PresentationConclusionCalcifying pseudoneoplasms of the neuraxis (CAPNON) is an extremely rare tumor, with nearly 150 cases have been reported in the literature. We present a case of CAPNON at foramen magnum (cervicomedullary junction). We also discuss the histological and radiological features of this rare pathology.A 35-year-old male patient presented to our center complaining of neck pain for the last 6 months and for the last 3 months has had headaches associated with nausea, blurred vision and papilledema. The patient’s magnetic resonance imaging showed the presence of right craniocervical junction intra-dural extramedullary tumor. Neuro examination showed no neurological deficits. He underwent midline suboccipital craniotomy with C1 laminectomy. The mass was completely resected, and histopathology confirmed it to be a CAPNON.We presented a new case of CAPNON at cervicomedullary junction. The tumor was radically resected, without any complications. Resection of this kind of tumor is curative, and the need for post-operative chemo or radiotherapy is unnecessary, which depends on the outcome of future research and the long-term follow ups. [ABSTRACT FROM AUTHOR]

Objective: Foramen magnum meningiomas (FMMs) are rare but challenging for neurosurgeons to remove because of their anatomic location where vital neuro-vascular structures exist. The difficulties encountered by a neurosurgeon during the surgery and important points during management of complications are underlined, which may help guide young neurosurgeons. Methods: In this report, management of FMMs are provided in 7 patients who underwent surgical treatment between 2012 and 2022. In this small series, 4 women and 3 men were included. Mean age was 54.28 ± 13.61 years with a mean follow-up of 45.71 ± 40.18 months. Results: Although gross total removal was achieved in all patients 3 showed complication (42.8%) during follow-up period. One showed recurrence. Conclusions: Gross total removal in grade 1 FMM does not guarantee total cure, and strict follow-up is mandatory. We conclude that anterior or anterolaterally located FMMs can be safely removed by midline suboccipital subtonsillar approach. More importantly, every possible complication before surgery should be discussed in detail with the patients and/or their next of kin in order to avoid compensation lawsuits, which is a devastating problem among surgeons all over the world. [ABSTRACT FROM AUTHOR]

Background: The posterior cranial fossa and the foramen magnum are the key anatomical components of the craniovertebral junction, which contain and transmit numerous vital neurovascular structures. Through foramen magnum important neural elements, the 7th to 12th cranial nerves, the cervical spinal nerves, the brainstem, the rostral aspect of the spinal cord, the cerebellum and the vermis, as well as various vascular structures such as the vertebral artery and its branches, the meningeal vessels and the venous sinuses. Materials and Methods: The present study conducted with 154 adult dry skull. We have observed the shapes of foramen magnum and classified as oval, round, tetragonal, pentagonal, hexagonal and irregular in shape. We have recorded morphometric measurements like anterior-posterior diameter and transverse diameter of foramen magnum. Values of each measurement were expressed in the form of Mean+SD. Results: Oval shape foramen magnum was observed in 52 number of skulls and the incidence was 33.76%, tetragonal shape was observed in 31 number of skulls and the incidence was 20.12%, hexagonal shape was observed in 18 number of skulls and the incidence was 11.68%, round shape was observed in 26 number of skulls and the incidence was 16.88%, pentagonal shape was observed in 13 number of skulls and the incidence was 8.44% and pear shape was observed in 14 number of skulls and the incidence was 9.12%. The Anterior - Posterior diameter (mm) Foramen Magnum was 36.84+4.62mm. The transverse diameter (mm) foramen magnum 30.45+2.82mm. Conclusion: In present study findings concludes hat the results may be helpful to the neurosurgeon in analysing the morphological anatomy of craniovertebral junction. The findings are also assisting in their pracice for the anthropologists, morphologists and clinical anatomists. [ABSTRACT FROM AUTHOR]

Objective To evaluate the changes in surgical approaches and treatment strategies for foramen magnum (FM) meningiomas located in the anterior or anterolateral aspect of the medulla oblongata. Methods The clinical data of 72 patients suffering a meningioma attached to dura of the anterior or anterolateral FM rim admitted to General Hospital of the People's Liberation Army from January 2007 to January 2022 were analyzed retrospectively. The relevant literature were reviewed. Results Tumor removal was accomplished via a posterolateral suboccipital retrocondylar approach in all patients. Total resection was achieved in 65 patients (90%). 7 patients (10%) of subtotal resection underwent cyberknife radiosurgery. 12 cases (17%) had hypoglossal nerve dysfunction, and 8 improved within 3 months after surgery. 18 cases (25%) experienced hoarseness and/or difficulty swallowing, 15 improved within 3 months after surgery, and 1 underwent tracheotomy due to posterior cranial nerve paralysis. 1 suffered from hemiplegia due to anterior spinal artery injury. There were no surgical deaths. No tumor recurrence was observed after a mean follow-up period of 3 years (range, 12-60 months) with clinical and MRI examination. Conclusions Microsurgery via retrocondylar approach to remove anterior and anterolateral FM meningiomas can not only meet the needs of surgical exposure, but also avoid excessive bone grinding, achieving good total resection rate, low complications, and long-term satisfactory therapeutic effect. The occurrence of serious complications such as postoperative hemiplegia is mainly due to intraoperative vascular damage. [ABSTRACT FROM AUTHOR]

Foramen magnum decompression (FMD) is a standard neurosurgical procedure, typically utilized to treat Chiari malformation. The aim of this educational project was to develop and validate a low-cost FMD simulation training model. Mold-based methods were used to develop a prototype. Feasibility was tested during an FMD training session for 17 neurosurgery trainees. Face and content validity were assessed through a Likert Scale. The perceived training benefit was determined using the Physician Performance Diagnostic Inventory Scale (PPDIS). A total of 87.5% successfully removed the C1 arch, 81.3% successfully performed an FMD, and 68.8% avoided injury to the underlying structures. The model scored highly for visual and tactile realism. The median confidence rating on PPDIS significantly improved from early learner to competent. We demonstrate feasibility, content, and face validity. Furthermore, this is a low-cost, portable model that can be easily replicated and used for simulation training. [ABSTRACT FROM AUTHOR]

Objective The aim this study is to present the results of the minimal invasive neuroendoscopic-assisted system application as an alternative to traditional surgery in patients with Chiari malformation type 1 (CM type 1) with/without syringomyelia. Design, Setting, and Participants In the study, data of 22 symptomatic patients were prospectively collected. Before and after the operation, patient characteristics, computed tomography, magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) flow dynamics MRI, and outcome scales scores were recorded. Foramen magnum decompression and C1 total laminectomy were performed. The fibrous band at the craniocervical junction was opened and a durotomy was performed. In patients with a syrinx, the pre- and postoperative axial and sagittal lengths of the syrinx were measured and compared. Results The mean age of the patients was 32 ± 5 years. There were eight male patients. Ten patients had syrinx. The mean visual analog scale (VAS) score before and after surgery was 8 ± 1.06 and 2.18 ± 1.13, respectively. When evaluated according to the Chicago Chiari Outcome Scale, there was improvement in 20 patients, while there was no change in 2 patients. Syrinx resolved completely in 3 of 10 (13.6%) patients with syringomyelia, and the syrinx volume decreased in 3 patients (13.6%). In 4 of 10 (18.1%) patients, there was no significant change in the syrinx volume. The average operation time was 105 minutes (80–150 minutes). The average blood loss was 40 mL (20–110 mL). Conclusion Although the study was limited due to the small number of patients with a short follow-up, endoscopic decompression was a safe and effective technique for surgery in CM type 1 patients. [ABSTRACT FROM AUTHOR]

Background: The foramen magnum is a centralised structure found at the base of the skull. This orifice is a passageway that allows secondary structures, such as the medulla oblongata and meninges, to pass through. The occipital condyles are small structures on either side of the foramen magnum, forming the craniovertebral joint. The hypoglossal canal is an orifice located on the occipital canal, providing a passageway for hypoglossal nerves. The study aimed to document the morphology and morphometry of the foramen magnum, occipital condyles and hypoglossal canals within a South African population. Materials and methods: Fifty skulls (n = 50) were randomly selected from the Department of Clinical Anatomy, School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal. This study investigated the morphological and morphometric parameters of the foramen magnum, occipital condyles and hypoglossal canal. The morphometric parameters were measured using a digital Vernier calliper. The data was statistically analysed using SPSS, and a p-value of <0.05 was deemed statistically significant. Results: The mean length and width of the foramen magnum was found to be 35.19 mm and 27.77 mm, respectively. The mean index of the foramen magnum was 1.3, which indicated that the foramen magnum was predominantly oval-shaped within the selected sample. The occipital condyles have a mean length and width of 21.73 mm and 12.87 mm, respectively. Furthermore, the most prevalent shape of the occipital condyles was oval. The mean length and width of the hypoglossal canals were 5.14 mm and 3.87 mm, respectively. While the most prevalent shape of the hypoglossal canal was oval and round on the right and left sides, respectively. Conclusions: The findings of this study may assist in reducing the risk of injury and mortalities during trans-condylar approach procedures. [ABSTRACT FROM AUTHOR]

BackgroundChiari I malformation (CMI) is characterized by inferior descent of the cerebellar tonsils through the foramen magnum and is associated with headache and neck pain. Many morphometric research efforts have aimed to describe CMI anatomy in the midsagittal plane using classical measurement techniques such as linear dimensions and angles. These methods are less frequently applied to parasagittal features and may fall short in quantifying more intricate anatomy with fewer distinct homologous landmarks.MethodsLandmark-based geometric morphometric techniques were used to asses CMI morphology in five anatomical planes of interest.ResultsSignificant shape differences between CMI and age/sex-matched controls were found in the midsagittal (Pseudo-F = 5.4841, p = 0.001) and axial planes through the rostral medulla (Pseudo-F = 7.6319, p = 0.001). In addition to tonsillar descent, CMI principal component 1 (PC1) scores in the midsagittal protocol were associated with marked anterior concavity of the brainstem and generalized verticality of the cerebellum with anterior rotation of its anterior lobe. In the axial medulla/cerebellum protocol, CMI PC1 scores were associated with greater anterior–posterior (A-P) dimension with loss of medial-lateral (M-L) dimension.DiscussionThese results suggest that CMI is associated with greater curvature of the brainstem and spinal cord, which may perturb normal neural activities and disrupt cerebrospinal fluid movements. Previous reports on the A-P diameter of the posterior fossa in CMI have conflicted; our findings of greater A-P cerebellar dimensionality with concomitant loss of width alludes to the possibility that more caudal aspects of the posterior cranial fossa are more bowl-like (homogenous in axial dimensions) and less trough-like or elongated in the M-L direction.

The foramen magnum (FM) occupies a well-protected position, making it particularly intriguing for forensic research. The necessity for methods to estimate sex from cranial fragments becomes evident when only a partial skull is available for identification. The objective of this study was to assess sex differences in anthropometric measurements, including the length of the foramen magnum (FML), width of the foramen magnum (FMW), foramen magnum area (FMA), and circumference, with the aim of developing a binary logistic regression model in Thai cadaveric donors. Sixty adult dry skulls underwent both intraclass and interclass correlation analyses. Subsequently, 240 adult dry skulls of known sex (120 males and 120 females) were meticulously measured and analyzed to determine the optimal threshold for sex determination. Morphometric analysis of the FM was carried out using vernier calipers, and the area of the FM was precisely calculated. The FML, FMW, FMA, and circumference were all found to be significantly larger in males than in females. Furthermore, FM circumference exhibited an AUC (Area Under the Curve) value of 0.908, signifying it as an excellent parameter for sex discrimination. Lastly, binary logistic regression was executed. Significant sex differences in FM circumference were consistently observed, demonstrating an accuracy of 81.62% when validated in 120 dry skulls.

Abstract Background The posterior cranial fossa (PCF) and the foramen magnum (FM) are the critical anatomical components of the craniovertebral junction region, which comprise and transmit numerous vital neurovascular structures. So, a fundamental knowledge of the basic radiological anatomy of PCF and FM is of paramount importance in the evaluation of associated pathologies and approaching these areas surgically. The aim of this study is to describe different linear and angular craniometric parameters of PCF, FM and surrounding territory based on reconstructed computed tomography (CT) images. Material and methods This study was conducted in our tertiary care hospital in northern India from the period of January 2023 to June 2023 on 120 patients, and CT screening was done for the head and spine region following a history of head injury. Results In this study, 120 patients were included, of whom 50.83% (n = 61) were females and 49.17% (n = 59) were males. Age ranged from 18 to 70 years with mean age of 43.5 ± 14.08 years. The mean values for linear craniometric parameters of PCF were statistically nonsignificant for different age groups. Statistically significant differences were found for twinning line (TL) (p

Aim: This retrospective study aimed to provide a comprehensive analysis of the surgical management of foramen magnum meningiomas (FMMs), focusing on patient characteristics, surgical approaches, complications, and postoperative outcomes. Materials and Methods: The study included 23 patients diagnosed with anterior or anterolateral FMMs who underwent surgical treatment between 2014 and 2022. The study encompassed clinical records, neurological assessments, radiological findings, and surgical approaches, with a focus on the far lateral approach (FLA). Evaluation of outcomes included Karnofsky Performance Scale (KPS) scores and The Neck Disability Index (NDI) scores. Surgical approaches and postoperative care strategies were detailed. The study also examined the relationship between tumor location and surgical techniques. Results: The analysis revealed that patients with FMMs presented with various clinical symptoms, including lower cranial nerve deficits, pyramidal tract syndrome, and sensory disturbances. The retrocondylar far lateral approach was predominantly utilized, resulting in various Simpson resection grades. Postoperative complications were observed, including cranial nerve deficits, cerebrospinal fluid leakage, and infections. Also, the study found patient KPS scores remained stable, and NDI scores showed no significant increases before and after surgery. Conclusion: Surgical management of FMMs is a complex task requiring meticulous planning, individualized approaches, and close attention to neurovascular structures. The study emphasized the diverse clinical presentations and surgical techniques associated with FMMs and highlighted the importance of ongoing research and collaborative efforts to enhance patient care in this challenging field. [ABSTRACT FROM AUTHOR]

The objective of this study is to determine whether the morphometric evaluation of the foramen magnum using computed tomography can be used as an accurate tool in estimating the sex of an individual. An extensive search of the databases, PubMed, ProQuest, Google Scholar, and Scopus, was carried out to procure articles that fulfilled the inclusion criteria. The AQUA tool was used to assess the quality of the included studies. A random effects model was used for the meta-analysis of the eligible studies using the STATA software, version 16, 2019 at 95% CI and p ≤ 0.05. Eleven eligible articles that measured the transverse and sagittal diameters of the foramen magnum using computed tomography were included in this study. The sagittal diameter of the foramen magnum was greater than the transverse diameter, and both the diameters were greater in males than in females. Meta-analysis revealed that both transverse and sagittal diameters were more reliable for male sex estimation. Since there is a dimensional variation between the male and female foramen magnum, it can be used for initial sex identification and also as an auxiliary to other advanced methods of sex estimation. [ABSTRACT FROM AUTHOR]

As technology has developed in recent years, the use of three‐dimensional (3D) scanners and printers has become widespread in the medical field. However, since this field is new, all kinds of methodological and experimental related studies gain importance. This study aimed to identify the differences between the calliper measurements by determining the craniometric data on the models constructed by scanning the crania of New Zealand Rabbits (Oryctolagus cuniculus L.), preferred as experimental animals, with a three‐dimensional scanner. Therefore, a total of 12 New Zealand rabbits including 6 females and 6 males were used. After the crania that comprised the study material were macerated, they were subjected to 3D scanning. After the scanning process was completed, they were craniometrically measured both on the scanned models and by using a digital calliper. Analysis of the craniometric data of the 3D scanner showed that there was a difference between sexes at the level of p < 0.05 in widest length between the external acoustic meatus (WLBEAM), skull width and Foramen magnum height (FMH) parameters and cranial index data, and at the level of p < 0.001 in the largest nasal width (LNW) parameter. A statistical difference was found between sexes in frontal length, WLBEAM, LNW and FMH parameters and cranial index values in craniometric data collected with the digital calliper (p < 0.05). Consequently, the data collected in this study were found to be close to each other in both methods, suggesting that the 3D scanner may be used in morphometric studies. [ABSTRACT FROM AUTHOR]

Background and Purpose: There has been limited literature regarding the bridging veins (BVs) of the medulla oblongata around the foramen magnum (FM). The present study aims to analyze the normal angioarchitecture of the BVs around the FM using slab MIP images of three-dimensional (3D) angiography. Methods: We collected 3D angiography data of posterior fossa veins and analyzed the BVs around the FM using slab MIP images. We analyzed the course, outlet, and number of BVs around the FM. We also examined the detection rate and mean diameter of each BV. Results: Of 57 patients, 55 patients (96%) had any BV. The median number of BVs was two (range: 0–5). The BVs originate from the perimedullary veins and run anterolaterally to join the anterior condylar vein (ACV), inferior petrosal sinus, sigmoid sinus, or jugular bulb, inferolaterally to join the suboccipital cavernous sinus (SCS), laterally or posterolaterally to join the marginal sinus (MS), and posteriorly to join the MS or occipital sinus. We classified BVs into five subtypes according to the draining location: ACV, jugular foramen (JF), MS, SCS, and cerebellomedullary cistern (CMC). ACV, JF, MS, SCS, and CMC BVs were detected in 11 (19%), 18 (32%), 32 (56%), 20 (35%), and 16 (28%) patients, respectively. The mean diameter of the BVs other than CMC was 0.6 mm, and that of CMC BV was 0.8 mm. Conclusion: Using venous data from 3D angiography, we detected FM BVs in most cases, and the BVs were connected in various directions. [ABSTRACT FROM AUTHOR]

Foramen magnum meningiomas are surgically challenging tumors because of their deep location and surrounding critical neurovascular structures. There are various approaches, most notably the far lateral approach. In this case, we aim to demonstrate how lesions in the ventral brain stem and cervical cord can be safely accessed through mastoid tip resection and vertebral artery transposition.By Je Beom HongReported by Author [Extracted from the article]

This article discusses the use of endoscopic endonasal approaches (EEA) in the management of foramen magnum meningiomas (FMM). FMM is a rare type of intracranial meningioma, and traditional treatment involves transcranial corridors. The study presents the experience of the authors in using EEA for FMM resection and highlights its role and limitations. The results show that EEA can be an alternative corridor for carefully selected patients with ventral FMM, especially when involvement or encasement of the anterior spinal arteries is suspected. However, CSF leak remains a significant limitation. [Extracted from the article]

This article, titled "Resection of Foramen Magnum Meningioma through Transcondylar Far Lateral Approach: Nuances and Techniques," discusses a case study of a 48-year-old female patient who presented with various symptoms related to a foramen magnum meningioma. The patient underwent surgery using a left transcondylar far lateral approach, with the use of monitoring techniques and a low profile aspirator. The surgery was successful, and the patient experienced improvements in her symptoms postoperatively. The article is authored by Raghuram Sampath and Jason Weistein. [Extracted from the article]

This article discusses the surgical management of foramen magnum meningiomas (FMM), which are benign tumors that account for a small percentage of all meningiomas. These tumors can cause neurological deficits and myelopathy due to their location near critical neurovascular structures. The study reviewed 15 patients who underwent surgical resection of FMM and found that the most common presenting symptoms were gait imbalance and headaches. The surgical approach was selected based on tumor location and origin, with the majority of patients undergoing the far lateral supracondylar approach. The study reported positive surgical outcomes with no postoperative mortalities and improvements in modified Rankin scale scores. The authors conclude that safe and effective resection of FMM can be achieved with careful techniques and consideration of the position of the vertebral artery. [Extracted from the article]

Background: Foramen magnum is the largest foramen in the skull. It acts as a significant signpost for the several structures that pass through it. Forensic specialists, neurosurgeons, and radiologists alike must have a thorough understanding of the morphometry and morphology of the foramen magnum. The lesion's in ventral proximity to the brain stem and cervicomedullary junction favours the transcondylar approach, which highlights the significance of the foramen magnum's morphometric analysis and accurate measurement of its dimensions. Aims: The present study aims to measure the various morphometric parameters of foramen magnum. Material and Methods: 52 dried human skulls were taken in this study excluding the broken and deformed ones. The anteroposterior and transverse diameters of foramen magnum were measured with the help of a vernier caliper. The area of foramen magnum was calculated using the above parameters. Results: The mean anteroposterior diameter and the transverse diameter of foramen magnum was found out to be 32.60mm ± 1.98mm SD and 27.94mm ± 1.73mm SD, respectively. The mean area of foramen magnum was found out to be 716.41mm2 ± 64.18mm2 SD. Various shapes of foramen magnum were observed. Foramen magnum was observed to have a round shape in 30%, oval in 22 %, Tetragonal in 18%, eggshaped in 16%, irregular in 10%, hexagonal in 4% and pentagonal in 4% of the cases. Conclusion: The current study's data has helped determine the morphology and the morphometry of foramen magnum. This data can prove to be of great importance for neurosurgeons, radiologists, clinical anatomists, and the forensic experts. [ABSTRACT FROM AUTHOR]

Background: The role of reduced intracranial compliance (ICC) in the outcome after foramen magnum decompression (FMD) was demonstrated in adults with Chiari malformation Type 1 (CMI). However, similar observations from children treated for CMI are missing. Methods: We reviewed pediatric cases of CMI referred to FMD between 2006 and 2022. Children with clinical and/or radiological signs suggesting reduced ICC (Group A) underwent overnight measurements of the pulsatile intracranial pressure (ICP): mean ICP wave amplitude (MWA) served as a surrogate marker of ICC. Children with more typical symptoms of CMI (Group B) underwent FMD without preoperative ICC estimation. This study presents the clinical, radiological, and outcome differences between these groups. Results: Sixty-four children (mean age 11.1 ± 4.3 years) underwent FMD: In Group A (n = 30), the finding of reduced ICC as estimated from preoperative ICP measurement resulted in CSF diversion (ventriculoperitoneal shunt) before FMD in 11 children. Two patients required shunt due to complications after FMD (total shunt rate 43%). In Group B (n = 34) treated with FMD without preoperative ICC estimation, five children (15%) required shunting due to complications. In Group A, we found a significantly higher frequency of headache, nausea, fatigue, and dizziness. The outcome assessed by the modified Chicago Chiari Outcome Scale (mean follow-up 83 ± 57 months) was comparable between the groups, but the complication rate after FMD was significantly lower in Group A (7% vs. 32%; p = 0.011). The number of procedures (ICP measurement, FMD, shunt, re-do FMD, shunt revisions) was significantly higher in Group A (2.6 ± 0.9 vs. 1.5 ± 1.1 per patient; p < 0.001). Conclusion: In symptomatic children with CMI, the preoperative estimation of ICC from the overnight measurement of pulsatile ICP was more reliable for identifying those with reduced ICC than clinical and radiological assessment alone. When children with abnormally reduced ICC were identified and treated with CSF diversion before FMD, the complication rate was significantly reduced. [ABSTRACT FROM AUTHOR]