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Retrospective case series. The aim of this study was to evaluate the clinical outcomes and effectiveness of using 3D printed implants in upper cervical spine and occipitocervical junction surgery. C2 primary tumor patients who required axial en bloc resection and other patients who required partial bone decompression using customized 3D printed implants or fixation devices for surgery were included. Evaluate the stability and surgical outcomes of 3D printed implants through perioperative and follow-up period. Five tumor patients underwent reconstruction using customized 3D printed artificial vertebral bodies, while another five patients with atlantoaxial joint dislocation underwent reduction and decompression using customized 3D printed internal fixation devices. The postoperative imaging results showed that the 3D printed structures had good immediate stability and had no signs of displacement or subsidence. Follow up showed that all five cases of vertebral body reconstruction had achieved fusion. Only one patient died one month after surgery due to infection and respiratory difficulties. Other patients showed excellent improvement in neurological function in follow up. The use of 3D printed implants in surgery involving the occipitocervical area is a feasible and reliable alternative choice. It is a valuable attempt for complex atlantoaxial dislocation that cannot be treated with conventional instruments. 3D printed implants can improve the safety and accuracy of surgery, provide good immediate stability, have a low incidence of subsidence, fewer related complications during the follow-up period. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman disease (RDD) with craniocervical junction involvement is a rare clinical entity. We present herein a case of a pediatric patient with craniocervical junction RDD which was surgically treated. A 10-year-old female with a history of B-cell acute lymphoblastic leukemia (B-ALL) in remission and RDD presented with frontal migraine headaches. She previously had a right posterior chest wall lesion which was biopsy-proven RDD. She was found on imaging to have a dural-based right craniocervical junction lesion. Given her history of B-ALL, after a multidisciplinary discussion, the decision was made to proceed with resection with possible initiation of cobimetinib or clofarabine. The patient underwent a suboccipital craniotomy, C1 laminectomy, and resection of the dural-based lesion. Gross total resection was achieved, and histopathology confirmed the diagnosis of RDD. She was discharged home on postoperative day 4. No recurrence was seen on follow-up imaging at 3 months. We conducted a systematic literature review examining all cases of pediatric intracranial RDD and all cases of craniocervical junction RDD. This represents, to the best of our knowledge, only the second case of pediatric craniocervical junction RDD. Although RDD is often self-limiting, medical treatment is often considered for intracranial disease, but tissue confirmation is necessary. Surgical resection provides histopathologic diagnosis and can sometimes serve as definitive treatment for a particular lesion. [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]

This paper presents the anatomical and biomechanical aspects of chronic instability of the craniocervical junction (CCJ) with a discussion on clinical diagnostics based on mobility tests and provocative tests related to ligamentous system injuries, as well as radiological criteria for CCJ instability. In addition to the structural instability of the CCJ, the hypothesis of its functional form resulting from cervical proprioceptive system (CPS) damage is discussed. Clinical and neurophysiological studies have shown that functional disorders or organic changes in the CPS cause symptoms similar to those of vestibular system diseases: dizziness, nystagmus, and balance disorders. The underlying cause of the functional form of CCJ instability may be the increased activity of mechanoreceptors, leading to "informational noise" which causes vestibular system disorientation. Due to the disharmony of mutual stimulation and the inhibition of impulses between the centers controlling eye movements, the cerebellum, spinal motoneurons, and the vestibular system, inadequate vestibulospinal and vestibulo-ocular reactions occur, manifesting as postural instability, dizziness, and nystagmus. The hyperactivity of craniocervical mechanoreceptors also leads to disturbances in the reflex regulation of postural muscle tone, manifesting as "general instability". Understanding this form of CCJ instability as a distinct clinical entity is important both diagnostically and therapeutically as it requires different management strategies compared to true instability. Chronic CCJ instability significantly impacts the quality of life (QOL) of affected patients, contributing to chronic pain, psychological distress, and functional impairments. Addressing both structural and functional instability is essential for improving patient outcomes and enhancing their overall QOL. [ABSTRACT FROM AUTHOR]

This study aims to discuss the identification of the C1 nerve root as an effective surgical approach to successfully locate the shunting point of craniocervical junction spinal dural arteriovenous fistula (CCJ-SDAVF) intraoperatively. This study included all patients with CCJ-SDAVF who underwent surgical treatment using the far-lateral transcondylar approach at a single institution from January 2017 to June 2023. Data on patient demographics, clinical and angiographic characteristics of CCJ-SDAVF, surgical details, and treatment outcomes were collected. Follow-up assessments were conducted for all patients until December 31, 2023. The study included a total of 7 patients, comprising 5 men(71.4%) and 2 women (28.6%), with an average age of 57.6 years. Among them, 4 patients (57.1%) developed diffuse subarachnoid hemorrhage(SAH), while 2 patients (28.6%) experienced progressive cervical myelopathy. The shunting points of all CCJ-SDAVFs, which exhibited engorged veins, were identified next to the C1 root. Complete obliteration of CCJ-SDAVFs was successfully achieved in all patients, as confirmed by postoperative angiography one month later. No recurrent CCJ-SDAVFs were observed two years after the operation. Among the patients, 5 (71.4%) experienced good functional recovery, as indicated by an mRS score ranging from 0 to 1, while the remaining 2 patients (28.6%) showed incomplete functional recovery. The surgical interruption of CCJ-SDAVFs is the preferred treatment option, given its high obliteration rate and favorable functional recovery outcomes. We advocate the identification of C1 spinal nerve root as a crucial surgical step to identify the shunting points of CCJ- SDAVFs. [ABSTRACT FROM AUTHOR]

To evaluate the feasibility of a novel method for occipitocervical fixation (OCF) through the endonasal corridor. Thin-cut computed tomography scans were obtained for 5 cadaveric specimens. Image segmentation was used to reconstruct 3D models of each O-C1 joint complex. Using computer-aided design software, plates were custom-designed to span each O-C1 joint, sit flush onto the bony surface, and accommodate screws. The final models were 3D-printed in titanium. For implantation, specimens were held in pin-fixation and registered to neuronavigation. A rigid 0º endoscope was used for endonasal visualization. An inverted U-shaped nasopharyngeal flap was raised to expose the occipital condyles and C1. The plates were introduced and fixed with bone screws. Computed tomography scans were obtained to assess screw accuracy and proximity to critical neurovascular structures. Screw entry points and trajectories were recorded. Endonasal OCF was performed on 5 cadaveric specimens. The mean starting point for occipital condyle screws was 6.17 mm lateral and 5.38 mm rostral to the medial O-C1 joint. Mean axial and sagittal trajectories were 7.98° and 6.71°, respectively. The mean starting point for C1 screws was 16.11 mm lateral to the C1 anterior tubercle and 6.39 mm caudal to the medial O-C1 joint. Mean axial and sagittal trajectories were 10.97° and −9.91°, respectively. Endonasal OCF is technically and anatomically feasible. The application of this technique may allow for same-stage endonasal decompression and fixation, offering a minimally invasive alternative to current methods of fixation and advancing surgeons' ability to treat pathology of the craniovertebral junction. Next steps will focus on biomechanical testing. [ABSTRACT FROM AUTHOR]

Purpose: The topic of osseous variations of the craniocervical junction is a complex morphological and embryological chapter of human anatomy, with a possible impact on neurogical and vascular functionality in this morphological variable region. Material & methods: An until now undescribed anatomical variation of the exoccipital part of the occipital bone has been observed after maceration at the outer skull base of a West-European 68-year-old male body donor. Results: On both sites of the foramen magnum accessory osseous processes were observed that arise from the jugular process and point towards the lateral margin of the foramen magnum. On the left site this process forms a full arc that bridges the condylar fossa completely. Conclusion: The observed osseous bridge over the condylar fossa has not been reported on before and can be explained by the partial persistence of a primordial vertebra between atlas and occipital bone: the Proatlas. The resulting accessory structure may affect due to its topographic conditions the V3-Segment of the vertebral artery and its accompanying nerves, and thus, play a role in diagnosis and therapy of vascular and/or neurological symptoms of head and neck. [ABSTRACT FROM AUTHOR]

Atlanto-occipital assimilation is a congenital craniovertebral junction malformation where the partial or complete fusion of the atlas and occiput occurs. Atlanto-occipital assimilation can be associated with numerous complications, including basilar invagination, atlantoaxial subluxation, Chiari malformation, congenital vertebral bodies fusion, and cord compression. As a result, vigilant identification and accurate reporting of atlanto-occipital assimilation are essential. The purpose of this review article is to discuss the numerous complications and associations of atlanto-occipital assimilation, such that an accurate diagnosis could be made for this commonly missed pathology. [ABSTRACT FROM AUTHOR]

Abstract Objective Autologous iliac bone is commonly used as a bone graft material to achieve solid fusion in craniocervical junction (CVJ) surgery. However, the developing iliac bone of children is less than ideal as a bone graft material. The matured rib bone of children presents a potential substitute material for iliac bone. The aim of this study was to evaluate the efficacy of autologous rib grafts for craniocervical junction surgery in children. Methods The outcomes of 10 children with abnormalities of the craniocervical junction who underwent craniocervical junction surgery between January 2020 and December 2022 were retrospectively reviewed. All patients underwent posterior fusion and internal fixation surgery with autologous rib grafts. Pre- and post-operative images were obtained and clinical follow-ups were conducted to evaluate neurological function, pain level, donor site complications, and bone fusion rates. Results All surgeries were successful. During the 8- to 24-month follow-up period, all patients achieved satisfactory clinical results. Computed tomography at 3–6 months confirmed successful bone fusion and regeneration of the rib defect in all patients with no neurological or donor site complications. Conclusion Autologous rib bone is a safe and effective material for bone grafting in craniocervical junction fusion surgery for children that can reduce the risks of donor site complications and increase the amount of bone graft, thereby achieving a higher bone fusion rate.

Objective: Autologous iliac bone is commonly used as a bone graft material to achieve solid fusion in craniocervical junction (CVJ) surgery. However, the developing iliac bone of children is less than ideal as a bone graft material. The matured rib bone of children presents a potential substitute material for iliac bone. The aim of this study was to evaluate the efficacy of autologous rib grafts for craniocervical junction surgery in children. Methods: The outcomes of 10 children with abnormalities of the craniocervical junction who underwent craniocervical junction surgery between January 2020 and December 2022 were retrospectively reviewed. All patients underwent posterior fusion and internal fixation surgery with autologous rib grafts. Pre- and post-operative images were obtained and clinical follow-ups were conducted to evaluate neurological function, pain level, donor site complications, and bone fusion rates. Results: All surgeries were successful. During the 8- to 24-month follow-up period, all patients achieved satisfactory clinical results. Computed tomography at 3–6 months confirmed successful bone fusion and regeneration of the rib defect in all patients with no neurological or donor site complications. Conclusion: Autologous rib bone is a safe and effective material for bone grafting in craniocervical junction fusion surgery for children that can reduce the risks of donor site complications and increase the amount of bone graft, thereby achieving a higher bone fusion rate. [ABSTRACT FROM AUTHOR]

Objective: To identify, quantify and compare clinical and concurrent imaging findings of occipital hypoplasia (OH), syringomyelia (SM) and atlanto-occipital overlapping (AO) in dogs with or without brachycephaly. Methods: A focused systematic search for literature was performed in the Web of Science™, PubMed and Google Scholar databases. Both authors screened and classified the identified articles using EndNote and appraised the articles using the Critical Appraisal Skills Program checklists. The main clinical and concurrent imaging features were extracted and evaluated for coexistence of OH, SM, AO, and other imaging findings. Results: Thirty-one articles were included in this minireview. For articles focusing on descriptions of OH, SM and AO, 249 dogs had at least one of these conditions, and 3 of these 249 dogs (1%) had coexistence of all three conditions. For articles focusing on descriptions of the dogs, OH, SM, and AO were identified in 552/19/11/11, 574/2/0/6, and 100/0/0/0 small brachycephalic, small non-brachycephalic, large brachycephalic, and large non-brachycephalic breeds, respectively. For all small brachycephalic dogs, the percentages of affected animals were 40% for OH (p = 0.01), 42% for SM (p < 0.01) and 7% for AO (p = 0.033). The number of dogs having AO and clinical symptoms is low (n = 5). Conclusion: OH, SM and AO are more likely to affect small dogs. AO might be limited to small brachycephalic breeds owing to the geometry of the craniocervical junction. Hence, AO alone might not lead to SM. In individual dogs, readers should carefully interpret the clinical relevance of OH or AO in the absence of SM. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to develop an accessible stepwise management algorithm for pediatric presentations of occipital condyle fractures (OCFs) based on a systematic review of the published literature regarding diagnostic evaluation, treatment, and outcomes. Methods: A systematic review of the literature was conducted on PubMed to locate English language studies reporting on the management of pediatric OCFs. Data extraction of clinical presentation, management strategies, imaging, and treatment outcome was performed. Results: A total of 15 studies reporting on 38 patients aged 18 years and younger presenting with OCFs were identified. Loss of consciousness (LOC), depressed level of consciousness, neck pain, decreased neck range of motion (ROM), and cranial nerve injury were the most common presenting symptoms. Diagnostic imaging included radiographs, computed tomography (CT) scans, magnetic resonance imaging (MRI), and functional radiographs to assess cervical stability. Treatment options varied and included soft collar, hard collar, and halo vest. All studies resulted in a complete healing of the OCF, with resolution of associated pain. Conclusion: The proposed treatment algorithm suggests a framework for the management of pediatric OCFs based on the available evidence (levels of evidence: 3, 4). This review of the literature indicated that a stepwise approach should be utilized in the management of isolated pediatric OCFs. [ABSTRACT FROM AUTHOR]

Osteogenesis Imperfecta (OI) is a genetic disease characterized by osteopenia and bone fragility in which the craniocervical junction is also affected. This is of special relevance due to the high prevalence in anomalies described in the literature as follows: basilar invagination, basilar impression, and platybasia. Methods. We analyzed 19 lateral skull radiographs and 14 magnetic resonance images (MRIs) of 28 patients with OI in which eight linear and five angular measurements were plotted to determine the existence of craniocervical junction anomalies and compare them with 38 lateral skull radiographs and 28 MRIs performed on age-matched healthy controls. Results. From the reference values obtained from the control sample for each age group, we established the limit value at which pathology could be suspected. Some of the variables studied showed a clear trend associated with growth. More than half of the patients (60.71%) presented an anomaly in the skull base. Conclusions. According to the diagnostic criteria used and taking +2.5 SD as the limit value, 10.71% of the patients had basilar invagination, 35.71% had basilar impression, and 39.29% had platybasia, the latter being the most common finding. [ABSTRACT FROM AUTHOR]

The occurrence of dural arteriovenous fistulas (DAVFs) at the craniocervical junction (CCJ) is an uncommon vascular malformation. The diagnosis and treatment of CCJ DAVFs present a formidable challenge. This study aims to investigate the effect of endovascular embolization and microsurgery on improving patient prognosis. This retrospective study included patients diagnosed with CCJ DAVFs who received treatment at the First Affiliated Hospital of Fujian Medical University between January 2000 and January 2023. The clinical records, imaging data, and treatment methods were obtained from the hospital's medical record system. The patients were classified into microsurgery and embolization groups based on the surgical technique employed for treatment. The primary outcome measures were surgical-associated neurological dysfunction (SAND) and long-term neurological outcomes. The Cox proportional hazard regression was utilized to determine hazard ratios and 95% confidence intervals (CI) to assess the relationship between treatment methods and prognosis. Kaplan-Meier survival analysis was employed to evaluate the incidence of SAND in both cohorts. This study recruited 46 patients with an average age of 53.72 ± 13.83 years. In the microsurgery group, there were 12 cases (26.1%) observed. While in the embolization group, there were 34 cases (73.9%). Of these patients, 16 (34.8%) experienced SAND after treatment. In the microsurgery group, there were 8 cases (75.0%), while in the embolization group, only 8 cases (23.5%) were reported. Specifically, the embolization group exhibited a significantly lower risk of SAND [adjusted hazard ratio = 0.259, 95% CI = 0.096–0.700; P = 0.008)] compared to the microsurgery group. Additionally, the combined Borden grade 2–3 was found to be significantly associated with SAND (adjusted hazard ratio = 3.150, 95% CI = 1.132–8.766; P = 0.028). The results of the Kaplan-Meier survival analysis indicated a statistically significant difference in the occurrence of favorable functional outcomes between the 2 groups (log-rank P = 0.0081). CCJ DAVFs are uncommon disorders characterized by a diverse range of clinical manifestations. The functional prognosis of endovascular treatment may be superior to microsurgery. [ABSTRACT FROM AUTHOR]

Purpose: Bridging veins (BVs) serve as a route of pial venous reflux, and its anatomy is essential to understand the pathophysiology of dural arteriovenous shunts (dAVSs) around the craniocervical junction (CCJ) (from the jugular foramen level to the atlantal level). However, the anatomical variations of the BVs and their proximal connections remained poorly elucidated. This study aimed to radiologically investigate the anatomy of the bridging veins around CCJ and discuss the clinical significance of these BVs in the dAVS. Methods: We investigated normal venous anatomy of the BVs from the jugular foramen level to the atlantal level using preoperative computed tomography digital subtraction venography in patients undergoing elective neurosurgery. BVs affected by the dAVSs in the same region were also evaluated. The three types of dAVS, craniocervical junction, anterior condylar, and proximal sigmoid sinus, were investigated. Results: We identified six BV groups: superolateral, anterolateral, lateral, posterior, inferolateral, and inferoposterior. The superolateral and inferolateral groups, connected with the proximal sigmoid sinus and suboccipital cavernous sinus, respectively, were the largest groups. Each group has a specific downstream venous connection. The association with dVASs was observed only in the inferolateral group, which was typically the sole venous drainage in most dAVSs at the CCJ. Conclusion: We reported detailed anatomy of BVs from the jugular level to the atlantal level, which enhanced our understanding of the pathophysiology of dAVSs in the corresponding region. [ABSTRACT FROM AUTHOR]

Background: Dural arteriovenous fistulas (DAVFs) at the craniocervical junction (CCJ) involving the first spinal nerve represent a particularly rare and challenging subtype of DAVFs, with holocord myelopathy secondary to cerebrospinal DAVFs being an exceedingly rare presentation. Case Description: We report the case of a 70-year-old woman who presented with progressive paraparesis over 2 weeks. Initial magnetic resonance imaging (MRI) of the spine showed extensive holocord myelopathy, leading to a misdiagnosis of inflammatory myelopathy and subsequent inappropriate steroid treatment at a local hospital, which exacerbated her neurological symptoms. On transfer to our institution and further evaluation with MRI and magnetic resonance angiography, a lower thoracic DAVF was initially suspected. However, comprehensive spinal angiography failed to localize the fistula, prompting cranial angiography, which ultimately identified a DAVF at the CCJ along the C1 nerve root, supplied by a small radiculomeningeal branch of the left vertebral artery. Successful management involved coagulation of the proximal draining vein, with follow-up imaging confirming complete fistula obliteration and resolution of the holocord edema. Conclusion: This case highlights the diagnostic and therapeutic challenges associated with DAVFs at the CCJ, particularly when presenting with holocord myelopathy. It underscores the importance of a high index of suspicion and the need for timely, accurate diagnosis and intervention to prevent permanent spinal cord damage in such rare and complex cases. [ABSTRACT FROM AUTHOR]

ObjectiveTo identify, quantify and compare clinical and concurrent imaging findings of occipital hypoplasia (OH), syringomyelia (SM) and atlanto-occipital overlapping (AO) in dogs with or without brachycephaly.MethodsA focused systematic search for literature was performed in the Web of Science™, PubMed and Google Scholar databases. Both authors screened and classified the identified articles using EndNote and appraised the articles using the Critical Appraisal Skills Program checklists. The main clinical and concurrent imaging features were extracted and evaluated for coexistence of OH, SM, AO, and other imaging findings.ResultsThirty-one articles were included in this minireview. For articles focusing on descriptions of OH, SM and AO, 249 dogs had at least one of these conditions, and 3 of these 249 dogs (1%) had coexistence of all three conditions. For articles focusing on descriptions of the dogs, OH, SM, and AO were identified in 552/19/11/11, 574/2/0/6, and 100/0/0/0 small brachycephalic, small non-brachycephalic, large brachycephalic, and large non-brachycephalic breeds, respectively. For all small brachycephalic dogs, the percentages of affected animals were 40% for OH (p = 0.01), 42% for SM (p

Schwannomas overall account for approximately 8% of primary brain tumors, with the majority of them arising from the vestibular nerves. 1,2 Non-vestibular schwannomas are considered rare, particularly ones arising from the accessory nerve, constituting only around 4% of craniovertebral junction schwannomas. 3,4 The far lateral approach and its variations is an important tool in the armamentarium of skull base neurosurgeons. It allows adequate exposure for accessing ventral and ventrolateral lesions of the craniocervical junction. 5-13 A 60-year-old female patient presented with a 3-month history of difficulty walking and progressive right-sided weakness. Magnetic resonance imaging demonstrated an extra-axial solid lesion at the craniocervical junction with significant enhancement on post-contrast imaging. The lesion was ventrolateral to the medulla, causing compression, displacement, and peritumoral edema. The patient consented to the procedure and underwent a far lateral suboccipital craniotomy with C1 hemilaminectomy in a lateral position. Tumor origins were identified at the left accessory nerve rootlet. The patient's postoperative course was uneventful. Follow-up magnetic resonance imaging revealed gross total resection and complete resolution of hemiparesis 3 months after the surgery. Microsurgical resection of tumors at the craniocervical junction is challenging. Preoperative planning and tailoring the approach are essential in the decision-making process to safely perform surgery. This video demonstrates, in detail, the steps, relevant anatomy, and technical nuances for accessory nerve schwannoma ressmoval. To the best of our knowledge, this is the first operative video showing the resection of a pure accessory nerve schwannoma with compression of the medulla. Under our institutional ethical review board regulations, approval was not necessary. [ABSTRACT FROM AUTHOR]

Osteogenesis Imperfecta (OI) is a genetic disease characterized by osteopenia and bone fragility in which the craniocervical junction is also affected. This is of special relevance due to the high prevalence in anomalies described in the literature as follows: basilar invagination, basilar impression, and platybasia. Methods. We analyzed 19 lateral skull radiographs and 14 magnetic resonance images (MRIs) of 28 patients with OI in which eight linear and five angular measurements were plotted to determine the existence of craniocervical junction anomalies and compare them with 38 lateral skull radiographs and 28 MRIs performed on age-matched healthy controls. Results. From the reference values obtained from the control sample for each age group, we established the limit value at which pathology could be suspected. Some of the variables studied showed a clear trend associated with growth. More than half of the patients (60.71%) presented an anomaly in the skull base. Conclusions. According to the diagnostic criteria used and taking +2.5 SD as the limit value, 10.71% of the patients had basilar invagination, 35.71% had basilar impression, and 39.29% had platybasia, the latter being the most common finding.

Spinal arteriovenous fistulae (AVFs) of the craniocervical junction are rare lesions that have variable angioarchitecture. These lesions are generally characterized by arteriovenous shunting at a single fistulous point, the disconnection of which is generally curative. 1 We present a case of bilateral dural AVF at the C2 level treated with surgical ligation (Video 1). Our patient was an elderly woman who presented after cervical magnetic resonance imaging was performed as part of work-up for right-sided shoulder tingling. This study demonstrated prominent flow voids along the dorsal and ventral surfaces of the craniocervical junction, concerning for an underlying vascular malformation. Formal angiography demonstrated arteriovenous shunting into the perimedullary venous plexus from a dural branch of the vertebral artery at the C2 level. Significant retrograde cortical venous drainage was noted. She was treated with a C1 and partial C2 laminectomy and clip ligation of the right-sided fistula. Postoperative angiography confirmed obliteration of the fistula but now demonstrated persistent arteriovenous shunting from second fistulous point at the contralateral C2 level. She was then taken back to surgery for ligation of the second fistula. Instances of multiple, distinct, and synchronous arteriovenous fistulae have been rarely reported in the literature. 2 In addition to demonstrating the nuances of surgical treatment of AVFs at this location, this case demonstrates the potential for synchronous AVFs and emphasizes the importance of thorough postoperative angiography. The patient provided consent to the production of this surgical video. [ABSTRACT FROM AUTHOR]

Background: The surgery on the craniocervical junction is associated with complex techniques that endanger the vertebral artery (VA), especially if there are some anatomical variations present, thereby increasing the risk of vascular injury, particularly during cervical decompression or instrumentation., Case Description: A case of a 60-year-old female with progressive myelopathy and craniocervical junction malformation is presented. Key preoperative imaging findings included basilar invagination, C1 assimilation, and os odontoideum, along with VA anomalies such as a tortuous, hypoplastic left VA arising anomalously from the aortic arch and a right VA with a V2 segment forming a high-riding medial loop into the C2 vertebral body. The surgical procedure was performed through a posterior approach using C-arm fluoroscopy, Doppler ultrasound, and intraoperative neurophysiologic monitoring, which achieved adequate deformity fixation and anterior decompression., Conclusion: Computed tomography angiography is the gold standard for assessing the preoperative VA anatomy at the craniocervical junction. Intraoperative Doppler ultrasound is invaluable because it minimizes the risk of sudden accidental injury to VAs in cases with abnormal anatomies., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Surgical Neurology International.)

Background: Spinal arteriovenous fistulae (AVF) located at the craniocervical junction (CCJ) are rare and usually present with hemorrhage. Bleeding is usually attributed to arterial feeders arising from the anterior spinal artery (ASA) and aneurysms located on such feeders. Perimedullary AVFs are typically found on the ventral surface of the spinal cord, which makes them difficult to treat through traditional microsurgical methods. In addition, their unique vessel angioarchitecture frequently precludes safe embolization. We present the first case of a CCJ perimedullary AVF successfully treated using flow diversion., Case Description: A 76-year-old man was brought to the emergency department after suddenly losing consciousness. On further evaluation, infratentorial subarachnoid hemorrhage and a perimedullary AVF at the ventral surface of the spinal cord were identified. The ASA originated from the left V4 segment, providing a single feeder to the lesion associated with a 2 mm aneurysm. After initial antiplatelet loading, 8 hydrophilic polymer-coated flow diverters were deployed to cover the ASA's origin in two sessions, achieving the complete occlusion of the lesion and the aneurysm 5 months later, without evidence of ischemic lesions., Conclusion: CCJ perimedullary AVFs can bleed with devastating consequences. These lesions can be challenging to treat through traditional microsurgical or endovascular techniques. Progressive occlusion with flow diversion is feasible in single-feeder AVFs, theoretically allowing blood flow reorganization to the cervical spinal cord., (Copyright: © 2024 Surgical Neurology International.)

Background: Occipitocervical arthrodesis has a variety of indications to treat craniocervical and atlantoaxial pathologies for which a selective cervical fusion would not provide sufficient stability. Over time, the indications for occipitocervical fusions (OCFs) have evolved, as new technologies and surgical techniques were developed. In this bibliometric analysis, we aim to explore the progression of OCF literature over time, analyzing the trends in publications and citations, publishing countries and authors, keywords, and topics., Methods: The Web of Science database was used for data retrieval on July 3, 2024, with the search "occipitocervical fusion" OR "occipito-cervical fusion" OR "occipitocervical arthrodesis" OR "occipital cervical fusion" OR "occipital cervical arthrodesis" OR ("OCF" AND "spine surgery"). Excel was used to create the citation analysis and publication trend figures, along with the publishing countries and author analysis. The bibliometric software VosViewer was used to generate the keyword co-occurrence network visualizations., Results: Overall, 762 articles were extracted. The number of pertinent publications and citations increased until 2020 before beginning to decrease. We found that Ehlers Danlos syndrome has become a more prevalent topic, as the association between Ehlers Danlos syndrome and craniocervical instability has received further scrutiny. "Dysphagia" continues to be a commonly cited topic, while, conversely, rheumatoid arthritis has decreased in publication frequency, possibly related to advances in medical management and surgical techniques. Overall, the United States, China, and Japan are the top publishing countries., Conclusions: This analysis of OCF literature provides a helpful overview of emerging trends and clinician concerns, especially as seen through the perspective of time., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Posterior inferior cerebellar artery (PICA) dissecting aneurysms are rare and typically present with subarachnoid hemorrhage (SAH) or ischemic symptoms, with a high risk of rebleeding in the acute phase. This case presents an atypical ruptured PICA aneurysm with a hematoma confined to the craniocervical junction and cervical cord, leading to a delayed diagnosis - a 41-year-old male with an atypical presentation of headache and neck pain without neurological deficits. Initial magnetic resonance imaging (MRI) revealed a hematoma extending from the craniocervical junction to the cervical spinal cord without intracranial SAH, leading to misdiagnosis as spinal subdural hematoma. As symptoms worsened, further investigation with MRI and digital subtraction angiography (DSA) uncovered a ruptured PICA-dissecting aneurysm. The patient underwent successful endovascular coil embolization with parent artery occlusion. This case highlights the importance of considering PICA-dissecting aneurysms in craniocervical junctions and spinal cord hemorrhage, even in the absence of typical intracranial SAH. It underscores the need for a high index of suspicion and comprehensive vascular imaging for timely diagnosis and treatment in atypical cases., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Nakamura Memorial Hospital Ethics Committee issued approval 2024082401. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Hiratsuka et al.)

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

Background Context: Our recent studies indicated that a high-riding vertebral artery (HRVA) is a common variant posing a risk of injuring the vessel during C2 instrumentation. However, several different types fit in the current definition of HRVA, which may require a different strategy for C2 screw placement., Purpose: To classify HRVA and provide a clinical aid for preoperative planning of C2 instrumentation. A secondary goal was to estimate coexistence of each HRVA type with the ipsilateral narrow C2 pedicle (NP)., Study Design: A retrospective observational study involving radiologic measurements of the estimated number of anonymized cervical computed tomography (CT) scans. STROBE checklist was applied., Patient Sample: A total of 908 potential screw insertion sites (PSIS) of 454 consecutive cervical CT scans were analyzed. The sample size was estimated using ScalaR SP function in RStudio., Outcome Measures: Three types of HRVA based on a series of C2 vertebral morphological parameters including the C2 isthmus height (C2IsH) and C2 internal height (C2InH). Also, the prevalences of each HRVA type and coexisting NP based on the C2 pedicle width (C2PW)., Methods: HRVA was defined as C2IsH of ≤5 mm and/or C2InH of ≤2 mm measured 3 mm lateral to the lateral border of the spinal canal. A narrow pedicle was defined as C2PW of ≤4 mm. Measurements were done using Syn.govia software. Interobserver, intraobserver, and inter-software agreement coefficients for C2IsH, C2InH, and C2PW parameters were adopted from our previous study. K-means cluster analysis was applied., Results: Prevalence of at least 1 HRVA was 24.9% (n=113 subjects) and 16.2% of PSIS (n=147 sites). Based on the measurements and K-means clustering, the following 3 types of HRVA have been distinguished: type 1-isthmic with only C2IsH being reduced and normal C2InH; type 2-internal with only C2InH being reduced and C2IsH within normal limits; type 3-isthmo-internal with both C2IsH and C2InH being reduced. Kruskal-Wallis test followed by unadjusted and Bonferroni-adjusted post-hoc multiple comparison analysis detected significant differences across the types. The prevalences of the newly identified types were as follows: 78.2%, 8.8%, and 12.9% for type 1, type 2, and type 3, respectively. 73.9% of type 1 HRVA, 53.8% of type 2 HRVA, and 100% of type 3 HRVA had a concomitant ipsilateral NP. Prediction of the HRVA types by the K-means clustering has been evaluated. Screw placement techniques for each type are proposed and discussed., Conclusion: We present the first classification system for the high-riding vertebral artery distinguishing 3 types based on the large homogenous cohort, which may serve as an adjunct to preoperative planning of C2 instrumentation. External validation of this classification scheme shall determine its further clinical utility., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Dural arteriovenous fistula (DAVF) of the craniocervical junction is exceptionally rare. The anatomy of the craniocervical junction area is very complex and is composed of the medulla and spinal cord along with intricate neurovascular structures. A thorough assessment of the angioarchitecture of the fistula is obligatory for choosing the most appropriate treatment for the patient. In this report, we describe the nuance of microsurgical obliteration of craniocervical junction DAVF utilizing intraoperative angiography. A 38-year-old male in a normal state of health was referred to our hospital for an abnormality in his brain checkup. Workup diagnostics showed a DAVF on the craniocervical junction area with feeders from ascending pharyngeal, vertebral, and occipital arteries, with the draining vein mainly to the basal vein of Rosenthal. Microsurgical obliteration of the main draining vein was done with the help of intraoperative digital subtraction angiography with a good outcome. Craniocervical DAVF is a rare entity. Meticulous evaluation of arterial and venous fistula points is necessary to decide the best treatment option for this case. Microsurgical obliteration is a feasible and more straightforward procedure for treating craniocervical DAVF., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Araki et al.)

Background: Neurenteric cysts are relatively rare benign congenital intracranial cystic lesions that enlarge rarely and very slowly. The authors present a case of an enlarging neurenteric cyst at the craniocervical junction with a fluid-fluid level on magnetic resonance imaging (MRI)., Observations: A 34-year-old man with no significant medical history underwent head MRI to investigate mild headaches. An incidental cystic lesion, approximately 8 mm in diameter, was revealed at the craniocervical junction. Serial follow-up MRI showed cyst enlargement with a fluid-fluid level. Four years later, the cyst reached a size of 15 mm and was surgically removed. The cyst contained cloudy fluid with a high protein concentration, without any bleeding or tissue fragments. Pathological examination confirmed the diagnosis of a neurenteric cyst. The patient recovered well, was discharged home, and has remained recurrence free for 2 years., Lessons: The growth dynamics of the relatively rapidly expanding neurenteric cyst at the craniocervical junction were monitored over time using MRI. This cyst exhibited the distinctive feature of a fluid-fluid level as it enlarged. Investigating the mechanisms underlying fluid-fluid level formation may offer novel insights into the pathogenesis of cyst enlargement. https://thejns.org/doi/10.3171/CASE24180.

Objective: Craniocervical junction arteriovenous fistulas (CCJ-AVFs) are complex vascular shunts that present a challenge for treatment. The aim of this study was to compare the clinical outcomes of microsurgery and endovascular embolization for CCJ-AVFs and to determine whether the treatment approach affected the obliteration rate and neurological improvement., Methods: The authors conducted a retrospective analysis of 64 patients who had undergone microsurgery or endovascular embolization for CCJ-AVF at one of two neurosurgical centers from January 2014 to February 2022. Additionally, a pooled analysis of 68 patients from 38 studies was performed. Baseline characteristics, angioarchitectural features, and clinical outcomes were compared between two treatment groups. A subgroup analysis of CCJ-AVFs with carotid artery (CA) feeders was also performed., Results: In the multicenter cohort, the complete obliteration rate was 95.1% with microsurgery, 81.8% with embolization via the CA, and 50.0% with embolization via the vertebral artery (VA). After adjusting for baseline and confounding features, the occlusion rate was significantly lower in the VA embolization group (adjusted OR 41.06, 95% CI 2.37-711.9, p = 0.01). No new-onset infarctions occurred in the microsurgical group, whereas 1 patient each in the CA and VA embolization groups experienced posttreatment infarction. Microsurgery demonstrated a neurological improvement rate similar to that in the CA embolization group (65.9% vs 63.6%, respectively). In the subgroup analysis of CCJ-AVF with CA feeders in the multicenter cohort, the occlusion rate and neurological improvement in the CA embolization group were comparable to those in the microsurgery group. The subgroup analysis in the pooled analysis revealed complete obliteration rates of 100.0% in the microsurgical group, 88.9% in the CA embolization group, and 66.7% in the VA embolization group., Conclusions: This study supports microsurgery as the best treatment modality for CCJ-AVFs, exhibiting the highest rates of complete obliteration. Conversely, embolization via the VA can result in a lower occlusion rate and less neurological improvement. In CCJ-AVFs with CA feeders, embolization via the CA can be a safe and effective alternative to microsurgery.

An in-depth understanding of the anatomy of the craniocervical junction (CCJ) is indispensable in skull base neurosurgery. In this paper, we discuss the osteology of the occipital bone, the atlas (C1) and axis (C2), the ligaments and the muscle anatomy of the CCJ region and their relationships with the vertebral artery. We will also discuss the trajectory of the vertebral artery and review the anatomy of the jugular foramen and lower cranial nerves (IX to XII). The most important surgical approaches to the CCJ, including the far lateral approach, the anterolateral approach of Bernard George and the endoscopic endonasal approach, will be discussed to review the surgical anatomy., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Odontoid pannus is an abnormal collection of degenerative or inflammatory tissue on the C1-dens joint that can result in severe spinal cord compression myelopathy. Treatment options vary depending on severity and etiology. In cases of severe cord compression, surgical management could be either through a purely posterior approach or in combination with an anterior decompression via endoscopic endonasal approach (EEA). This case presents a 77-year-old female who underwent posterior cervical fixation for odontoid pannus causing dramatic cervical myelopathy who failed to improve over a 6-month period and required anterior transodontoid pannus resection and decompression via EEA. The video can be found here: https://stream.cadmore.media/r10.3171/2024.1.FOCVID23176., Competing Interests: Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this publication.The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this publication., (© 2024, The Authors.)