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Background: Chiari malformation type 1 (CM-1) is characterized by cerebellar tonsil herniation through the foramen magnum and can be associated with additional craniovertebral junction anomalies (CVJA). The pathophysiology and treatment for CM-1 with CVJA (CM-CVJA) is debated. Objective: To evaluate the trends and outcomes of surgical interventions for patients with CM-CVJA. Methods: A systematic review of the literature was performed to obtain articles describing surgical interventions for patients with CM-CVJA. Articles included were case series describing surgical approach; reviews were excluded. Variables evaluated included patient characteristics, approach, and postoperative outcomes. Results: The initial query yielded 403 articles. Twelve articles, published between 1998-2020, met inclusion criteria. From these included articles, 449 patients underwent surgical interventions for CM-CVJA. The most common CVJAs included basilar invagination (BI) (338, 75.3%), atlantoaxial dislocation (68, 15.1%) odontoid process retroflexion (43, 9.6%), and medullary kink (36, 8.0%). Operations described included posterior fossa decompression (PFD), transoral (TO) decompression, and posterior arthrodesis with either occipitocervical fusion (OCF) or atlantoaxial fusion. Early studies described good results using combined ventral and posterior decompression. More recent articles described positive outcomes with PFD or posterior arthrodesis in combination or alone. Treatment failure was described in patients with PFD alone that later required posterior arthrodesis. Additionally, reports of treatment success with posterior arthrodesis without PFD was seen. Conclusion: Patients with CM-CVJA appear to benefit from posterior arthrodesis with or without decompressive procedures. Further definition of the pathophysiology of craniocervical anomalies is warranted to identify patient selection criteria and ideal level of fixation.

Background: Craniovertebral junction (CVJ) tumors are challenging due to their unique anatomical location. This study aimed to evaluate the complexities in dealing with such precarious CVJ extradural lesions over the decade., Methods: Twenty-seven patients of extradural CVJ tumors operated between 2009 and 2018 were included. The demographic details, neurological status, surgical approach, extent of resection, type of fixation, complications, and outcome at final follow-up were recorded for each patient., Results: The mean age of the patients was 39.5 ± 20 years. Most (17/27) of the patients had involvement of a single level. Clivus was the most common (9/17) involved region followed by atlas (7/17) vertebrae. Majority of the patients (13/27) were operated through the posterior-only approach. About 15 patients (55.5%) had instability or extensive lesions that necessitated posterior fixation. None of the patients underwent anterior fixation. Gross and near total excision were achieved in 10 patients (37%) and 3 patients (11%) respectively while 14 patients underwent subtotal excision of tumor. On histopathological analysis, clival chordoma (8/27) was found to be the most common pathology followed by giant cell tumor (6/27), plasmacytoma (4/27), and multiple myeloma (2/27). Most patients (13 out of 27) had the same neurological status after the surgery. Six patients (22%) improved post-operatively with decreased weakness and spasticity. Thirteen (48%) patients underwent adjuvant radiotherapy., Conclusions: This retrospective study provides valuable insights into managing extradural CVJ tumors and highlights the importance of individualized approaches for optimal outcome., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: Basilar impression (BI) is a rare yet debilitating abnormality of the craniovertebral junction, known to cause life-threatening medullary brainstem compression. Our study analyzes surgical approaches for BI and related outcomes., Methods: A systematic review was conducted using PubMed, Google Scholar, and Web of Science electronic databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to critically assess primary articles examining BI., Results: We analyzed 87 patients from 65 articles, mostly female (55.17%) with a mean age of 46.31 ± 17.94 years, commonly presenting with motor (59.77%) and sensory deficits (55.17%). Commonly employed procedures included posterior occipitocervical fusion (24.14%), anterior decompression (20.69%), and combined anterior decompression with posterior fusion (21.84%). Patients who underwent anterior approaches were found to be older (55.38 ± 17.67 vs. 45.49 ± 18.78 years, P < 0.05) and had a longer duration from symptom onset to surgery (57.39 ± 64.33 vs. 26.02 ± 29.60 months, P < 0.05) compared to posterior approaches. Our analysis revealed a significant association between a longer duration from symptom onset to surgery and an increased likelihood of undergoing odontoidectomy and decompression (odds ratio: 1.02, 95% confidence interval: 1.00-1.03, P < 0.05). Furthermore, after adjusting for all other covariates, a history of rheumatoid arthritis and the use of a posterior approach were significantly associated with an elevated risk of postoperative complications (P < 0.05)., Conclusions: The treatment approach to complex craniovertebral junction disease should be tailored to the surgeon's experience and the nature of the compressive pathology., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The mandible is one of the most commonly fractured facial bone in children. The principle of management of pediatric mandibular fracture bears no resemblance to its adult counterpart due to concerns regarding the growing facial skeleton and development of dentition. Pediatric mandibular fractures with traumatic retroclival hematoma and concomitant craniovertebral junction injuries is an extremely rare entity reported in literature. Manipulation during operative procedure for mandibular fractures could potentially cause serious injuries to the spinal cord, leading to significant disability and mortality. The authors report a case of a 12-year-old child with right parasymphysis and left angle of mandible fracture treated by open reduction internal fixation (ORIF). Her craniovertebral ligamentous injuries and retroclival hematoma were treated conservatively with good outcome. The presence of a halo frame for cervical spine stabilization during ORIF contributed to the difficulty in operative management.

Chiari malformations, characterized by the herniation of cerebellar tonsils through the foramen magnum, are complex neurosurgical conditions that pose significant diagnostic and therapeutic challenges. 1 Traditional interventions, such as foramen magnum decompression, have been the mainstay of treatment but are not universally effective, especially in cases with underlying atlantoaxial instability. However, recent studies highlight the importance of atlantoaxial instability in their pathogenesis, shifting the therapeutic focus towards atlantoaxial fixation. 2 Research shows that atlantoaxial fixation can effectively address the underlying instability, leading to better symptomatic relief and neurological outcomes compared to traditional decompression methods. 3 , 4-17 The findings from these studies consistently demonstrate that atlantoaxial instability is a critical factor in the development of Chiari malformations. Atlantoaxial fixation not only resolves the mechanical instability but also leads to significant symptomatic relief and improved neurological outcomes. Comparative analysis indicates superior efficacy of atlantoaxial fixation over traditional decompression techniques, especially in patients with concurrent basilar invagination and syringomyelia. This surgical Video 1 illustrates a case of a 20-year-old male patient with tonsillar herniation, syringomyelia, atlantooccipital assimilation, atlantoaxial instability, basilar invagination and dorsolumbar scoliosis, who was successfully managed with cervical fixation using a bilateral C1 lateral mass and C2 transpedicular screw construct. This surgery was able to achieve clinical and radiologic improvement without the need for a foramen magnum decompression. The patient consented to the procedure and to the publication of his images., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Primary osteosarcoma of craniovertebral junction is extremely rare and reports in paediatric patients are limited. The symptoms are subtle and mostly underestimated.Case presentation.We present an unusual case of a 11-years old girl affected by an extensive and metastatic osteosarcoma of the atlas presented with cervicalgia and right torticollis refractory to medical treatment. The patient underwent open biopsy confirming the malignant histology. Conclusions: Cervicalgia with or without a torticollis refractory to medical treatment, in absence of history of fell or trauma, is highly suspicious and should be considered as a warning sign for a severe pathology and it should not be neglected.

Neurenteric cysts are uncommon benign endodermally-derived epithelial-lined cystic lesions of the central nervous system. We report a case of neurenteric cyst in the craniocervical junction and review of the literature.A 17-year-old boy complained of a 9-month history of progressive headaches. Neurological examination did not reveal any abnormalities. A computed tomography scan was performed demonstrating a hypodense lesion in the craniocervical junction and the magnetic resonance imaging (MRI) revealed an approximately 19 × 24 × 23 mm prebulbar cyst that induced posterior displacement of the medulla. Four months later, the patient developed right hemiparesis and limitation of his neck movements. Further MRI showed that the lesion had increased a little in size. Given this, a suboccipital craniotomy was performed with right C1 laminectomy, achieving complete excision of the cyst, and the peribulbar region and the lower cranial nerves were released. After 4 months, he was asymptomatic and playing football again, and 3 years later, MRI did not demonstrate any signs of growth.

Objective: Spondylotic changes in the cervical spine cause degeneration, leading to cervical spinal canal stenosis. This stenotic change can affect cerebrospinal fluid (CSF) dynamics by compressing the dural sac and reducing space in the subarachnoid space. We examined CSF dynamics at the craniovertebral junction (CVJ) using time-spatial labeling inversion pulse magnetic resonance imaging (Time-SLIP MRI) in patients with cervical spinal canal stenosis., Methods: The maximum longitudinal movement of the CSF at the CVJ was measured as length of motion (LOM) in the Time-SLIP MRI of 56 patients. The sum of ventral and dorsal LOM was defined as the total LOM. Patients were classified into 3 groups depending on their spinal sagittal magnetic resonance imaging findings: control (n = 27, Kang classification grades 0 and 1), stenosis (n = 14, Kang classification grade 2), and severe stenosis (n = 15, Kang classification grade 3)., Results: Time-SLIP MRI revealed pulsatile movement of the CSF at the CVJ. The mean total, ventral, and dorsal LOM was 14.2 ± 9, 8.1 ± 5.7, and 3.8 ± 2.9 mm, respectively. The ventral LOM was significantly larger than the dorsal LOM. The total LOM was significantly smaller in the severe stenosis group (6.1 ± 3.4 mm) than in the control (16.0 ± 8.4 mm) or stenosis (11 ± 5.4 mm) groups (P < 0.001, Kruskal-Wallis H-test). In 5 patients, postoperative total LOM was improved after adequate decompression surgery., Conclusions: This study demonstrates that CSF dynamics at the CVJ are influenced by cervical spinal canal stenosis. Time-SLIP MRI is useful for evaluating CSF dynamics at the CVJ in patients with spinal canal stenosis., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Patients with craniovertebral junction anomalies are more likely to undergo craniovertebral junction procedures because of neurologic complications. Vertebral arteries (VAs) are more prone to injury in these cases because of an often anomalous course, with potentially disabling or grave sequel. In our patient with partially occipitalized atlas, CT angiogram revealed that 1 of the VAs passed through the bony canal in the occipitalized and/or fused bone, whereas the VA on unfused side was also unexpectedly anomalous and of C2 segmental type. To the best of our knowledge, such anomaly has never been reported in studies of patients with occipitalized atlas in the literature.

The craniovertebral junction (CVJ) involves the atlas, axis, and occiput along with the atlanto-occipital and atlantoaxial joints. The anatomy and neural and vascular anatomy of the junction render the CVJ unique. Specialists treating disorders that affect the CVJ must appreciate its intricate anatomy and should be well versed in its biomechanics. This first article in a three-article series provides an overview of the functional anatomy and biomechanics of the CVJ., (Copyright © 2023 Elsevier Inc. All rights reserved.)

In this third article in a 3-article series on the craniocervical junction, we define the terms "basilar impression," "cranial settling," "basilar invagination," and "platybasia," noting that these terms are often used interchangeably but represent distinct entities. We then provide examples that represent these pathologies and treatment paradigms. Finally, we discuss the challenges and future direction in the craniovertebral junction surgery space., (Copyright © 2023. Published by Elsevier Inc.)

The craniovertebral junction (CVJ), or the "first junction," can be affected by a variety of pathological states. Some of these conditions could represent a gray area in that they can be treated by general neurosurgeons or such specialists as skull base or spinal surgeons. However, some conditions are best managed with a multidisciplinary approach. The importance of in-depth knowledge of the anatomy and biomechanics of this junction cannot be overemphasized. Identifying what represents clinical stability or instability is key to successful diagnosis and, hence, treatment. In this report, the second in a 3-article series, we describe our approach to managing CVJ pathologies in a case-based fashion to illustrate key concepts., (Copyright © 2023. Published by Elsevier Inc.)

Objective: To describe and evaluate the steps required to perform a combined endoscopic endonasal/transoral transclival transodontoid approach for anterior decompression of the craniovertebral junction., Methods: The endoscopic endonasal transclival transodontoid approach combined with endoscopic transoral decompression was performed on 4 cadaveric specimens. Evaluation of this combined technique; a review of the literature; and the nuances, advantages, and pitfalls are reported., Results: Adequate wide anterior decompression was achieved in all specimens. This combined approach allowed the preservation of the anterior arch of C1 without injuring the eustachian tube anatomy and avoiding internal carotid artery manipulation., Conclusions: Mastery of both techniques allows for a safe and comfortable surgical corridor. The transoral and transnasal approaches should not be considered as either/or techniques, but rather as a complement to each other. However, as with all new or developing techniques, there is a steep learning curve, which requires ample training in the skull base laboratory., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: The course of the vertebral artery and its relationship to the C 0-1-2 structures render it particularly vulnerable to mechanical trauma. In the present study, we investigated the course of vertebral arteries along the craniovertebral junction (CJ) to cast light on the biomechanical aspects of aneurysm formation, focusing mainly on the relation of the vertebral artery injuries to the CJ bony landmarks. Herein, we report our experience with fourteen cases of craniovertebral junction vertebral artery (CJVA) aneurysms and their presentations, management, and outcomes., Materials and Methods: We extracted from 83 vertebral artery aneurysms only those 14 cases whose aneurysms were located at the C 0-1-2 . We reviewed all medical records, including operative reports and radiologic images. We divided the CJVA into 5 segments and then carefully reviewed the cases, largely focusing on the CJVA segments involved in the aneurysm. Angiographic outcomes were determined by angiography, which was scheduled at 3-6 months, 1, 2.5, and 5 years postoperatively., Results: A total of 14 patients with CJVA aneurysms were included in the present study. 35.7 % had cerebrovascular risk factors, while 23.5 % had other predisposing factors such as an AVM, an AVF, or a foramen magnum tumor. Predisposing factors in the form of neck trauma, both direct and indirect, were identified in 50 % of cases. The segmental distribution of aneurysms was as follows: three (21.4 %) at CJV 1, one (7.1 %) at CJV 2, four (28.6 %) at CJV 3, two (14.3 %) at CJV 4, and four (28.6 %) isolated to the CJV 5 segment. Of the 6 indirect traumatic aneurysms, 1 (16.7 %) was located at CJV 1, 4 (66.7 %) were located at CJV 3 and 1 (16.7 %) was located at CJV 5. The 1/1 direct traumatic aneurysm (100 %) from the penetrating injury was located at CJV 1. 100 % of cases with cerebrovascular risk factors, the affected vessels were on the dominant side. 42.9 % of cases presented symptoms of a vertebrobasilar stroke. All 14 aneurysms were managed only endovascularly. 85.8 % of patients we implemented flow diverters only. 57.1 % of follow-up cases were completely occluded angiographically, and 42.9 % of cases were near-completely or incompletely occluded at 1, 2.5, and 5-year follow-ups., Conclusions: The current article is the first report of a series of vertebral artery aneurysms located in CJ. Herein, the association of vertebral artery aneurysm, hemodynamics, and trauma is well established. We clarified all segments of the CJVA and showed that the segmental distribution of CJVA aneurysms significantly differs between traumatic and spontaneous cases. We showed that treatment with flow diverters should be the mainstay of CJVA aneurysm treatment., Competing Interests: Competing interests The authors declare that they have no competing interests during the writing or submission of this article., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Odontoidectomy for symptomatic irreducible ventral brainstem compression at the craniovertebral junction may result in spine instability requiring subsequent instrumentation. There is no consensus on the importance of C1 anterior arch preservation in prevention of iatrogenic instability. We conducted a systematic review of the impact of C1 anterior arch preservation on postodontoidectomy spine stability., Methods: PubMed, Embase, Scopus, Web of Science, and Cochrane were searched following the PRISMA guidelines to include studies of patients undergoing odontoidectomy. Random-effect model meta-analyses were performed to compare spine stability between C1 anterior arch preservation versus removal and posttreatment outcomes between transoral approaches (TOAs) versus endoscopic endonasal approaches (EEAs)., Results: We included 27 studies comprising 462 patients. The most common lesions were basilar invagination (73.3%) and degenerative arthritis (12.6%). Symptoms included myelopathy (72%) and neck pain (43.9%). Odontoidectomy was performed through TOA (56.1%) and EEA corridors (34.4%). The C1 anterior arch was preserved in 16.7% of cases. Postodontoidectomy stabilization was performed in 83.3% patients. Median follow-up was 27 months (range, 0.1-145). Rates of spine instability were significantly lower (P = 0.004) when the C1 anterior arch was preserved. Postoperative clinical improvement and pooled complications were reported in 78.8% and 12.6% of patients, respectively, with no significant differences between TOA and EEA (P = 0.892; P = 0.346). Patients undergoing EEA had significantly higher rates of intraoperative cerebrospinal fluid leaks (P = 0.002)., Conclusions: Odontoidectomy is safe and effective for treating craniovertebral junction lesions. Preservation of the C1 anterior arch seems to improve maintenance of spine stability. TOA and EEA show comparable outcomes and complication rates., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: To describe a management algorithm for cervicovertebral junction (CVJ) TB based upon disease severity and neurological status at presentation., Methods: Retrospective cohort study of 52 patients treated for microbiologically or clinically-diagnosed CVJ TB at a tertiary referral center in a TB endemic area were identified. Data were gathered about presenting symptoms, baseline neurological status, management strategy, and management outcomes. Patients were categorized by a modified Lifeso Stage., Results: Fifty-two patients were included (Mean age 28.5 ± 13.4 yr, 48% male): 18 Lifeso Stage I, 15 Stage II, and 19 Stage III. All presented with pain, 19 (37%) with neurological symptoms, and 5 with inability to ambulate. Stage II and III patients were more commonly myelopathic at presentation (p < 0.01) than Stage I patients. Only Stage II/III lesions required traction or surgical intervention; Stage III lesions more commonly required surgery than Stage II lesions (100% vs. 73%; p = 0.03). Among surgically-treated Stage II and III lesions, Stage III lesions had longer symptom prodromes (5.1 ± 2.2 vs. 3.3 ± 1.4mo; p = 0.03), more commonly had lateral mass collapse at presentation (58 vs. 9%; p = 0.02), and more commonly required occipitocervical fusion (68 vs. 9%; p < 0.01)., Conclusion: Based upon these data, Stage I lesions may be treated conservatively, unless presenting with a neurological deficit. Conversely, Stage III lesions require open reduction and instrumentation due to irrevocable underlying bony damage. Reducible Stage II lesions with absent or mild neurological symptoms can be treated conservatively, but irreducible lesions and those with concomitant neurological deficits merit surgery., Competing Interests: Conflict of interest Daniel Sciubba reports consulting agreements with Baxter, DePuy-Synthes, Medtronic, Stryker, none of which are related to the present work. None of the other authors report a conflict of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Treatment of Chiari malformation (CM) is controversial, especially when it coexists with "stable" or Type II basilar invagination (CM + II-BI). Precise evaluation of craniovertebral junction (CVJ) stability is crucial in such patients; however, this has never been validated. This study aimed to dynamically evaluate atlanto-condyle and atlantoaxial stability by kinematic computed tomography (CT) and report its surgical treatment., Methods: The study recruited 101 patients (control, CM, and CM + II-BI groups: 48, 34, and 19 patients, respectively). During kinematic CT, the CVJ stability-related parameters were measured and compared between the 3 groups. The surgical strategy for treating CM + II-BI was based on these results. Preoperative and postoperative images were acquired, and functional scores were used to assess the outcome., Results: Among the 3 groups, the length of the clivus and the height of the condyle were the shortest in the CM + II-BI group, which was accompanied by the greatest rotation of the atlas and atlanto-condyle facet movement on cervical flexion and extension. Moreover, in such patients, increased Chamberlain's baseline violation indicated the aggregate invagination of the odontoid in the flexed position, and asymmetric displacement of atlantoaxial facets was observed. Seventeen CM + II-BI patients underwent surgical treatment with atlantoaxial distraction and occipitocervical fusion. The syringomyelia width and tonsillar herniation decreased significantly, and functional scores indicated symptom relief and good outcomes., Conclusions: CVJ instability, especially the ultramovement of atlanto-condyle facets, commonly exists in II-BI as evaluated using kinematic CT. The surgical strategy of atlantoaxial distraction and occipitocervical fusion should be considered to treat such patients., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The far-lateral suboccipital approach and its variants, including the transcondylar, supracondylar, and paracondylar approaches, are essential skull base techniques for the neurosurgeon to expose and treat pathologies located at the ventral and ventrolateral craniovertebral junction. An understanding of the surgical anatomy and technical nuances of these approaches is vital for preventing catastrophic brainstem or spinal cord injury, neurovascular injury, and/or cranial nerve injury. This is achieved by carefully studying the location, the rostral-caudal and lateral extents of the lesion itself, and the anatomy of the surrounding structures on preoperative imaging. The amount of bony exposure should be tailored to each specific lesion to avoid unnecessary bone drilling and therefore decrease the risk of potential craniocervical instability. Minimizing retraction of the cerebellum, brainstem, and spinal cord is important for preventing neurologic injury; therefore, appropriate intraoperative head positioning and adequate bony exposure should be ensured, especially for more ventrally located lesions. A thorough knowledge of the anatomy of the extradural and intradural segments of the vertebral artery, and the lower cranial nerves, in relation to the lesion is also critical. For almost all lesions, the far-lateral suboccipital route with no or minimal condylar drilling is more than adequate for removing the most ventral lesions. Herein, we discuss the indications, general and preoperative considerations, and surgical anatomy and technical nuances of this approach., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Posterior cervical approaches for atlantoaxial and craniovertebral junction pathologies with or without instrumentation are often associated with excessive soft tissue dissection and bleeding consequent with disruption of the venous plexus. A few minimally invasive approaches to this region have been reported from clinical and cadaveric studies in an effort to minimize blood loss, reduce soft tissue dissection, and decrease postoperative pain; however, unilateral minimally invasive approaches have not been described. Here, we describe a minimally invasive atlantoaxial and craniovertebral approach., Methods: Using fresh cadavers, we performed a novel, right-sided, muscle-sparing minimally invasive C1-C2 laminotomy with laminoplasty for access to the atlantoaxial level and craniovertebral junction and used the traditional approach on left sides., Results: Using this approach, the atlantoaxial space and craniovertebral junction with wide and generous exposure via unilateral soft tissue dissection and muscle splitting was achieved. After exposure, the musculoosseous unit was easily repositioned, thus allowing for C1-C2 laminoplasty. Grossly, no damage to the vertebral artery or regional nerves was noted., Conclusions: We present a novel, unilateral minimally invasive approach to reach the atlantoaxial and craniovertebral junction. This could allow for faster postoperative recovery, less pain and opioid requirement, and increased maintenance of atlantoaxial stability. Such a technique, after being confirmed in patients, could optimize this surgical technique., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: Atlantoaxial instability, although rarely reported in the literature, can be associated with cervical dystonia (CD) and may lead to compression of the cord at the craniovertebral junction. We present a case series of 4 patients of longstanding CD with neurologic complications. Treatment strategies and challenges are discussed., Methods: Retrospective analysis of 4 cases of longstanding CD with complications of myelopathy or radiculopathy., Results: The average age at onset of complications was 28 years (range, 17-37). The average duration of CD was 23.75 years. Narrowing of the craniovertebral junction was seen in 3 patients, of which 2 had os odontoideum, and 1 had rotational malalignment at the atlantoaxial joint. One patient had disc desiccation with bulge and intramedullary signal changes in the cord at C3-4 level. Medical treatment was not satisfactory, but botulinum toxin was partly useful in all. One patient had sequelae of myelopathy and did recover partially after deep brain stimulation. Of the 2 patients who underwent surgical fixation with a fusion of the spine, one improved, and the other had no improvement due to irreversible cord damage. The overall outcome was satisfactory only in 2 patients., Conclusions: Early-onset CD can lead to cord complications at a young age and at higher levels of the cervical spine and at the cervicovertebral junction. Comprehensive management by a multidisciplinary team is crucial to prevent complications early., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: This article discusses the procedure of foramina magnum and Magendie dredging, summarizing the pathologic changes in the intradural region of the craniocervical junction in patients with syringomyelia and the pathophysiologic mechanism of cerebrospinal fluid (CSF) circulation obstruction., Methods: Clinical data from 50 adult patients with syringomyelia treated at Xuanwu Hospital from July 2018 to January 2019 were collected and retrospectively analyzed. All operations were performed with foramina magnum and Magendie dredging, and all intradural factors that may have induced the obstruction of CSF circulation were recorded., Results: Intradural pathology was found in all patients. The pathologic changes that may have caused obstruction of the CSF circulation include tonsil occupying the foramen magnum and overlying foramen of Magendie in 88% (44/50), intertonsillar arachnoid adhesions in 36% (18/50), tonsil to medulla arachnoid adhesions in 18% (9/50), medialized tonsils in 70% (35/50), vermian branch of posterior inferior cerebellar artery in 22% (11/50), arachnoid veil in 16% (8/50), cisterna magna cyst in 4% (2/50), and tonsil to dura mater arachnoid adhesions in 8% (4/50). Mean duration of follow-up was 13.3 months. The long-term effective rate was 96.0%. Postoperative magnetic resonance imaging revealed that the size of the syringomyelia was reduced or completely resolved in 88% of patients. The mean preoperative Japanese Orthopaedic Association score was 12.9 ± 3.1, which improved to 14.7 ± 3.2 (P < 0.05) at last clinical follow-up., Conclusions: Intradural pathology that causes CSF circulation obstruction exists in many forms. Relieving the obstruction of the foramen magnum and foramen of Magendie is key to surgical treatment., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The endoscopic endonasal approach (EEA) has been accepted as an alternative option for diseases at the craniovertebral junction. However, the inferior destination through the endoscopic endonasal approach is anatomically higher than that of the transoral approach. Therefore, preoperative assessment of accessibility is mandatory for appropriate selection of indication. Using a navigation system, we examined the inferior limit through the endonasal route and evaluated the relationships between surrounding anatomicl structures and the lowest point., Methods: This study included patients who underwent endoscopic transsphenoidal surgery for intrasellar lesions at our hospital (N = 23). At the start of surgery, the lowest point (target point [TP]) was marked with a straight probe under guidance of the navigation system. We measured 4 parameters on preoperative computed tomography: nasal length, hard palate length, anterior-posterior diameter of the nasopharynx, and nasopalatine angle. Patients were classified into groups depending on whether the TP was at or above (group A) or below (group B) the hard palatine line., Results: TPs were above the hard palatine line in 15 patients (group A) and below the hard palatine line in 8 patients (group B). No TPs reached the nasopalatine line. Nasal length (P = 0.03) and nasopalatine angle (P = 0.01) were larger in group B than in group A. There were no significant differences in anterior-posterior diameter of the nasopharynx or hard palate length., Conclusions: The hard palatine line is a reliable parameter for assessing the inferior limit of the endoscopic endonasal approach. Nostril size affects accessibility with surgical instruments., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Atlanto-occipital transarticular screw fixation (AOTSF) has rarely been reported for fixation of the craniovertebral junction (CVJ)., Methods: A retrospective chart review of all pediatric patients (less than 18 years of age) with an attempt of AOTSF for fixation of traumatic CVJ instability was conducted., Results: A total of 4 patients (2 boys and 2 girls; ages 2, 3, 5, and 8 years) who suffered from acute traumatic CVJ instability managed during 2007-2018 underwent an attempted AOTSF. In 2 patients, this method was technically successful. In the other 2 instances, we were not able to engage the screw into the occipital condyle. These were converted to standard occipital plate, rod, and screw fixation. All were placed in a halo subsequently for a minimum of 3 months. Three patients were fused at last follow-up (range, 17-48 months). One patient after successful AOTSF did not fuse. There were no surgical complications or revision procedures., Conclusions: AOTSF was feasible in half of pediatric patients suffering from traumatic CVJ instability. Therefore, intraoperative salvage options and strategies should be on hand readily. In the pediatric population, where bony anatomy may pose challenges to fixation, this technique may offer a viable first-line option in selected cases, despite the overall modest success rate., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: We herein outline the experience matured in our equipped Cranio-Vertebral Junction Laboratory for anatomic dissection., Methods: An extreme lateral approach (ELA) was performed on 4 fresh cadavers and submandibular approach was performed on 5. An endoscope and navigation-assisted far lateral approach (FLA) was performed in 5 injected specimens. In these specimens, a transoral approach was also performed, as well as a neuronavigation-assisted comparison between transoral and transnasal explorable distances., Results: As calculated with neuronavigation, statistically significant differences both in the explored craniocaudal (P = 0.003) and lateral (P = 0.008) distances were observed between the transoral approach and endoscopic endonasal approach. In FLA, neuronavigation facilitated identification and partial removal of the occipital condyle; in one case, during endoscopic intradural exploration, tearing of the emerging roots of the 11th cranial nerve occurred. In ELA, the site where the accessory nerve pierces into the sternocleidomastoid muscle was found at a distance from the tip of the mastoid between 3 and 4 cm., Conclusions: During dissections, as in the clinical setting, endoscope and image guidance give the surgeon a constant orientation, increasing the accuracy and the safety of the approach. Nonetheless, the encumbrance of the endoscope could represent a limit in deep and narrow corridors as those running across the craniovertebral junction, especially in "oblique" FLA and ELA, in which the surgical target is often hidden by a delicate tangle of nerves and vessels. Its use appears more suitable and safer in "straight" approaches as transoral and transnasal in which there are no neurovascular structures interposed., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Odontoidectomy for basilar invagination and craniovertebral junction pathology traditionally has been performed using a transoral route. However, the endoscopic endonasal approach to the anterior craniovertebral junction may offer safer and more effective access when compared with transoral approaches. The objective of this study is to review the surgical outcomes and complications associated with endoscopic endonasal odontoidectomy., Methods: This study is a retrospective chart review of all adult patients who underwent an endoscopic endonasal odontoidectomy at a single tertiary care center between January 2011 and May 2019., Results: Seventeen patients who underwent endoscopic endonasal odontoidectomy were included. The median age at admission was 67 years (range: 33-84 years) and 65% of the patients were female. One patient (1/17, 6%) had vertebral artery injury, which had to be coiled with no neurologic deficits, and 4 patients (4/17, 24%) had intraoperative CSF leaks with no postoperative leak. Fourteen (14/17, 82%) patients were extubated by postoperative day 1. Three patients (3/17, 18%) developed postoperative sinus infections and required antibiotics. Eight patients (8/17, 47%) developed transient postoperative dysphagia. One patient (1/17, 6%) had postoperative epistaxis and 1 patient (1/17, 6%) had postoperative lower cranial nerve symptoms. The median length of hospital stay was 13 days (range: 2-44 days)., Conclusions: Although the transoral approach has been the traditional route for anterior decompression of the craniovertebral junction, endoscopic endonasal odontoidectomy is a feasible and well-tolerated procedure associated with satisfactory patient outcomes and low morbidity., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Tuberculosis (TB) in the atlantoaxial joint is a rare disease. However, the treatment of atlantoaxial TB with neurologic impairment is controversial. The aim of this review is to provide clinical outcomes of surgical and nonsurgical management of atlantoaxial TB., Methods: Databases including PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched for English literature describing the treatment of atlantoaxial TB with neurologic deficits. The outcomes of conservative and surgical treatment approaches, including treatment failure, death, changes in neurologic impairment, and complications, were compared by performing odds ratio (OR) analysis., Results: Overall, 24 studies (247 patients) meeting the inclusion criteria were analyzed. Ninety-four patients (38%) were treated conservatively and 153 (62%) patients were treated surgically. The rate of poor outcomes was greater in the conservative group (14.89%) than in the surgery group (1.3%) (OR, 0.081; 95% confidence interval [CI], 0.016-0.39).There was no significant difference in mortality between the conservative (1.06%) and surgery (3.27%) groups (OR, 3.28; 95% CI, 0.494-27.381). There was no significant difference in muscle power improvement between the 2 treatments (conservative, 95.7%; surgery:, 94.8%; OR, 1.353; 95% CI, 0.291-4.925)., Conclusions: Conservative and surgical treatments both significantly improved neurologic deficits in most patients. Compared with conservative treatment, surgical treatment reduced treatment failures without significantly increasing the rates of neurologic deficit improvement or mortality., (Copyright © 2019. Published by Elsevier Inc.)

Background: Surgical management of extensive skull base tumors, such as chordoma and chondrosarcoma, remains very challenging. The need for gross total removal to improve survival must be weighed against the risk of injury to neurovascular structures and the loss of stability at the craniovertebral junction. In cases of tumors that are already compromising craniovertebral junction stability, the occipital condyle can be exploited as a deep keyhole to reach the clivus, petrous apex, and sphenoid sinus., Methods: We performed an anatomic study on 7 cadaveric specimens to describe the main landmarks and boundaries of the corridor. We also provide a clinical case to demonstrate the feasibility of the approach., Results: In all specimens, using the space provided by the condyle, it was possible to drill the petrous bone up to the posterior wall of the sphenoid sinus following the direction of the inferior petrosal sinus. To successfully complete the approach, after the hypoglossal canal was exposed, endoscopic assistance was needed to overcome the narrowing of the visual field provided by the microscope., Conclusions: In cases of invasive skull base tumor involving the craniovertebral junction and affecting its stability, the occipital condyle can be exploited as a deep keyhole to the homolateral and contralateral petrous apex, clivus, and sphenoid sinus., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: C2 vertebral body (axis) lesions are often approached anteriorly and combined with posterior stabilization of the craniovertebral junction (CVJ). The anterior approach has its limitations. A posterolateral corridor is an alternative access to the C2 body lesions, and this alone may suffice in selected cases. We describe our experience with C2 body lesions, dealt primarily through a posterior approach, and propose an algorithm in the management of such cases., Methods: Ten patients with axis lesions were operated through a midline posterior approach followed by posterior stabilization of the CVJ in the same sitting. Their preoperative and follow-up clinico-radiologic details were reviewed., Results: The lesions included aneurysmal bone cysts (n = 2), fibrous dysplasia (n = 2), chordoma (n = 2), Ewing sarcoma (n = 1), metastases (n = 1), post-traumatic malunion (n = 1), and post-inflammatory deformity (n = 1). All patients presented with worsening neck pain. Five also had spastic quadriparesis. There were no perioperative complications. All showed clinical improvement at follow-up. Only 2 patients (chordoma: n = 1; aneurysmal bone cyst: n = 1) required an additional anterior procedure., Conclusions: Adequate debulking or total excision of lesion, neural decompression, and stabilization of the CVJ for axis body lesions can be achieved through a single midline posterior approach in most cases. If required, an anterior approach may be later added depending on the final histopathology., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Isolated unilateral alar ligament injury (ALI) is a very rarely diagnosed condition, with only 9 cases reported in the literature. The purpose of this study is to determine clinical, diagnostic, and biomechanical features of unilateral ALI., Methods: A total of 6 patients diagnosed with ALI were included in this series. The hospital records and radiologic imaging of admission and follow-ups were investigated retrospectively., Results: Rotation of the neck and/or hyperflexion was always present as a mechanism of injury. The patients were neurologically intact. All patients presented with mild neck pain aggravated by head rotation. On computed tomography (CT) scans, the dens was observed to be displaced to the opposite side. Magnetic resonance imaging (MRI) showed a widened lateral dens-atlas space with high signal intensity. All patients underwent lateral flexion-extension CTs for the confirmation of craniovertebral junction (CVJ) stability. The patients were treated with hard collars. The follow-up MRI of 3 patients obtained at the third month showed normal lateral dens-atlas interval and recovered ligaments. All patients were pain free after 6 months., Conclusions: Unilateral ALI appears to be more common but misdiagnosed than previously thought. Trauma mechanism consists of hyperflexion and contralateral rotation. Neck pain aggravated with rotation is the most significant clinical finding. Dens lateralization is the most important finding in CT scans. An MRI focusing on the CVJ is essential for the diagnosis. The stability of CVJ must be checked with a flexion-extension CT scan. Unilateral ALI is a stable condition and responds to conservative treatment., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Anterior craniovertebral junction (CVJ) surgery has continued to be one of the most debated neurosurgical topics. The transoral approach (TOA) has been considered the choice for this region. However, it has some limitations and a not negligible degree of surgery-related morbidity. With the advent of endoscopy, the endoscopic endonasal approach (EEA) was developed, which minimized morbidity and improved exposure. To the best of our knowledge, despite the extensive reported data, a comparative anatomical study has not been performed and no definitive consensus has been reached on the indications for both approaches., Methods: We compared the TOA and EEA to the CVJ using the previously described operability score (OS), calculated at 4 different targets: the C1 tubercle (C1), the lowest exposed point of the odontoid process (C2), the basion (BS) and the middle clivus (MC). The higher the OS for the selected targets, the more favorable the approach., Results: The TOA had higher OSs at the MC, C1, and C2 targets, and the EEA showed greater OSs at MC and C1. The TOA and EEA had similar OSs at the BS. These results have shown that the OS is more favorable at C1-C2 using the TOA and the OSs at the MC and BS were similar., Conclusions: The OS is an effective method to compare surgical approaches. The present study demonstrated the maximal exposure capability of the 2 approaches. The TOA seemed to be superior for lower targets and the EEA for upper targets. Because of the strong variability in the CVJ anatomy and pathological features, we suggest considering the OS as a further tool to better define the best surgical approach., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Patients with Down syndrome (DS) have an increased incidence of multisystem disorders, like cardiovascular, neurologic, gastrointestinal, respiratory, and musculoskeletal disorders. Craniovertebral junction instability is a common illness in DS patients, and they may often be affected by vertebral artery (VA) anomalies., Case Description: In this paper we present neuroradiologic findings of a 34-year-old female patient affected by DS with atlantoaxial subluxation, scheduled for transoral decompression of C1-C2 and posterior occipitocervical fixation. The preoperative angio-computed tomography scan showed a peculiar anatomic variation in the entrance of the VA at the level of the C2 transverse foramen (TF). Normally, the segment of VA, named V2, becomes intraforaminal on average at the TF of C6., Conclusions: We reviewed the literature about the incidence of anatomic variations of the V2 segment in both the general population and the one affected by DS, and although numerous cases of anomalous course, none reported a C2 TF entry point. Ignoring such extremely rare anatomic variation during anterior, posterior, or lateral surgical approach to the cervical spine can lead to inadvertent injury and potentially serious complications like arterial dissection, thrombus, vascular spasm, fistula, pseudoaneurysm, cerebral ischemia, and death., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: The occipitalization of the atlas (OA) is always associated with multiplanar dislocation and olisthy of the C1 over C2 facets, which may change the anatomical relationship between the internal carotid artery (ICA) and the atlas. The purpose of this current study is to identify the location of the ICA relative to the anterior aspect of the atlas in patients with OA and define the clinical implications for screw placement., Methods: We retrospectively reviewed the computed tomography angiography data of 86 patients with OA and 86 control subjects. Several parameters were also measured to quantitatively evaluate the mutual relationship., Results: In the OA group, 25.6% of ICAs were located in area 3 and 74.4% in area 2, whereas the percentages were 57.4% and 42.6%, respectively, in the control group. There were 73 (42.4%) ICAs in which the shortest distance between the dorsal surface of the ICA and the ventral cortex of the atlas was less than 4 mm in the OA group and only 50 (29.1%) in the control group. The ideal angulation of C1 screw trajectory was about 5 degrees more medial in the OA group than that in the control group (P < 0.01)., Conclusions: The risk of ICA injury is much higher in OA patients than in non-OA patients during the C1 screw placement. A mean medial angulation about 20 degrees will permit a long and safe screw purchase, but should be individualized. We recommend careful preoperative computed tomography angiography evaluation in all patients before surgery., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The craniovertebral junction (CVJ) may be affected by several diseases. It is an anatomically complex region, involving the osteoligamentous, vascular, and nervous structures, which makes surgery challenging. In a case of ventral compression, an anterior approach is preferable, although posterior fixation is often required. Anterior transmucosal approaches are associated with high rates of complications. However, decompression and fixation by the use of retropharyngeal extramucosal approaches may be challenging., Objective: To investigate the feasibility of a single-stage, anterior, extramucosal submandibular (SM) approach modification to the CVJ for simultaneous decompression and stabilization., Materials and Methods: This was a preliminary cadaveric feasibility study on 2 injected specimens. A variation of the SM approach with a short "boomerang" incision, microsurgical decompression of the ventral CVJ, and a new hybrid construct for an anterior atlantoaxial stabilization was investigated. The surgical approach, the decompression, and the instrumentation technique have been described. In addition, intraprocedural images and radiographs and also postprocedural computed tomographic images were collected. Furthermore, surgical exposure, working corridors and angles, and decompression grade were measured., Results: The SM approach provided wide exposure of the ventral CVJ and the possibility for instrumentation and decompression by removing the anterior arch of C1 and the odontoid process., Conclusion: A single- stage anterior extramucosal SM approach for decompression and stabilization of the CVJ is feasible and could result in shorter surgical duration, avoiding the complications related to both the transmucosal approach and the prone position, although specific related risks exist. Mechanical investigation of this hybrid system and in vivo studies are needed to confirm our results., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Surgical intervention at the craniovertebral junction requires preoperative and intraoperative planning to get optimum postoperative results. Careful positioning minimizes the risk of iatrogenic injury and can also facilitate adequate surgical exposure. Tortuous venous channels that are usually encountered as the dissection proceeds may cause excessive bleeding before reaching the lateral mass (LM). However, both localization and placement may be made easier by altering the dissection technique and modifying the patient's position. Traditionally, the military tuck position is described for the dorsal approach to the craniovertebral junction. The objective of this study is to emphasize the role of arc or bow like position, a modification of prone position for adequate placement of C1 LM screw in these cases., Methods: We operated on 68 patients with atlantoaxial dislocation in an arc or bow position from January 2013 to September 2018. In 58 patients, at least 1 C1 LM screw was placed., Results: This position helped in easy and early recognition with easy trajectory for the C1 LM screw placement and less work force., Conclusions: Visual axis to the lateral mass of C1 in an arc/bow position with head elevation puts C1 LM more in the visual axis of the operator, which makes the trajectory straight without causing much angulation while inserting the screw. At the same time, the axis vertebra guides the surgeon to the C1 lateral mass with no handling of dura., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: A clival plate and screw fitted to the craniovertebral junction (CVJ) were developed in our previous studies. However, the anatomy of intracranial structures related to clival screw placement has not been studied., Objective: To measure the intracranial anatomic parameters delineating the basilar plexus and vertebrobasilar artery (VBA) course and to determine the relationship between brainstem and clivus for safer screw placement., Methods: Morphometric analysis of the VBA was conducted on 95 patients (48 men, 47 women) by CT angiography (CTA) and of the basilar plexus and brainstem on 80 patients (44 men, 36 women) by magnetic resonance imaging (MRI) The narrowest distance between the VBA and the intracranial clivus and the distance between the VBA and the median line of the skull were measured on the axial plane at different parts. The relative positions of point I (intersection of vertebral artery and basilar artery) and the pharyngeal tubercle were analyzed. The distance between the clivus and the brainstem was measured at different levels., Results: As the VBA ascended the distances to the intracranial clivus and the midline decreased. In 83.3% cases, point I was above the pharyngeal tubercle, and in only 9.5% cases was it located on the vertical line drawn from pharyngeal tubercle. The smallest safe space between the intracranial clivus and the brainstem was 7.46 mm at the lower part., Conclusion: Appropriate screw size at the lower clivus and the pharyngeal tubercle may help avoiding inadvertent injury to the brainstem and the VBA. Preoperative CTA and MRI of the CVJ are suggested to guide the surgeon in this regard., (Copyright © 2019. Published by Elsevier Inc.)

Background: Craniovertebral junction arachnoid cysts are uncommon. Among those reported, ventrally located arachnoid cysts at the extremes of age have been even rarer. We report a successfully managed case of a ventrally placed arachnoid cyst in an 88-year-old man using an unconventional surgical approach., Case Description: An 88-year-old man presented to us with complaints of tingling and numbness in both upper and lower limbs. He had a weak handgrip on both sides. Spinal magnetic resonance imaging (MRI) showed a non-contrast-enhancing cystic lesion over the anterior lip of the foreman magnum that had displaced the cervicomedullary junction posteriorly. The lesion was homogenously hypointense on T1-weighted MRI and hyperintense on T2-weighted MRI. The lesion was excised using a posterior approach. The cyst contents were drained, followed by complete wall excision. Complete improvement in clinical symptoms and an absence of neurological deficits were noted in the patient., Conclusion: Arachnoid cysts are congenital lesions and can present at the extremes of age. Ventrally placed small symptomatic arachnoid cysts can be managed successfully through the posterior approach, especially in the elderly population., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: Although many studies have investigated the benefits of multimodal intraoperative monitoring (MIOM) during cervical spine surgery, the benefits of MIOM in craniovertebral junction (CVJ) surgery remain unclear. The objectives of the present study were to report our clinical experience in CVJ surgery with the use of MIOM and to identify risk factors that could affect MIOM changes during surgery of CVJ pathology., Methods: We reviewed the MIOM records of 146 patients who had undergone high cervical spinal surgery. The patients were grouped by the MIOM data recorded during surgery; the patients were included in either the MIOM or non-MIOM change group. The analyzed risk factors included demographic, myelopathy, preoperative Japanese Orthopedic Association (JOA) score, spinal cord diameter, and surgical factors. Univariate and multivariate analyses were performed to identify the risk factors for changes in MIOM data during surgery and postoperative neurological deficits., Results: Our results revealed that the incidence of postoperative neurological complications was 4.1% after CVJ surgery; this rate was significantly greater in the MIOM change group than in the non-MIOM change group (21.7% vs. 0.8%; P < 0.01). Multiple regression analysis revealed that preoperative myelopathy, preoperative JOA score, and congenital anomaly/tumor were independently associated with MIOM changes during surgery., Conclusions: Postoperative neurological complications are not uncommon after CVJ surgery, and the incidence was significantly greater in the MIOM change group. Preoperative myelopathy, preoperative JOA score, and CVJ pathology related to congenital anomaly or tumor were independent risk factors for changes in MIOM data during surgery., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Craniovertebral junction diseases, although considered rare, are common in northern parts of India. This study was conducted to evaluate the clinico-radiologic and surgical outcome of patients with a minimum follow-up of 1 year. Our study also compared bony fusion among various techniques of posterior fusion., Methods: This retrospective study was performed with 38 patients who met the inclusion criteria for analysis. These patients were contacted by telephone and letters, and their clinical examination and radiologic investigations were performed at a follow-up visit. The preoperative, postoperative, and follow-up clinical evaluations of the patients were done using the Nurick grading system., Results: The age range was 4-60 years with an average of 20.5 years. There were 31 male and 7 female patients, with a male:female ratio of 4.43:1. There were 13 cases of fixed atlantoaxial dislocation (AAD), 17 cases of mobile AAD, 6 cases of traumatic AAD, and 2 cases of postinfective AAD. The majority of these patients (n = 29; 76.31%) had neck pain and cerebellovestibular disturbances (n = 27; 71.1%). Sphincter disturbances were observed in 9 patients. An increase in craniovertebral angle was observed in postoperative period in all patients. Initially, 84% of the patients had a poor Nurick grade; this was reduced to 28% after the surgical intervention. One hundred percent bony fusion was attained in patients who underwent rigid fixation technique, and 80% was attained using a semirigid fixation technique., Conclusions: The key to successful management of craniovertebral junction disease is individualized selection of judicious surgical intervention from various available techniques., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objectives: Chiari malformations (CMs) are a group of disorders defined by anatomic anomalies of the cerebellum, brainstem, and craniovertebral junction (CVJ). In this study, we aimed to investigate morphometry of posterior fossa and CVJ in subtypes of CM and in control group, and to bring up a matter a correlation with demographic data and subtypes of CM., Patients and Methods: The study group included patients managed for CM between 2012 and 2016 and control group. Radiological evaluation was studied by special programs and formulas. Intracranial volumes and morphometric datas of posterior fossa and CVJ were recorded retrospectively., Results: Of the 141 patients, 91 had CM and 50 were control group participants. Mean age was 34.75. Patients were classified as CM-0 (n:10), CM-1 (n:45), CM-1.5 (n:21), CM-2 (n:15). There were statistically significance between Chiari subtypes by syringomyelia (SM) presence (p ˂ 0.01), SM localization (p ˂ 0.01), posterior fossa volume (PFV) (p ˂ 0.01), length of clivus (LoC) and length of subocciput (LoSO) (p ˂ 0.01 for both), angle between clivus and subocciput (C-SO angle) (p ˂ 0.01), and clivo-dental angle (C-D angle) (p ˂ 0.01)., Conclusion: On morphometric comparison of CM subtypes we concluded that etiological differences lead to morphological differences. CM-2 has remarkable differences from both other subtypes and the control group., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: We compiled a comprehensive literature review on the anatomic and clinical results of endoscopic approaches to the craniocervical junction (CVJ) to better contribute to identify the best strategy., Methods: An updated literature review was performed in the PubMed, OVID, and Google Scholar medical databases, using the terms "Craniovertebral junction," "Transoral approach," "Transnasal approach," "Transcervical approach," "Endoscopic endonasal approach," "Endoscopic transoral approach," "Endoscopic transcervical approach." Clinical series, anatomic studies, and comparative studies were reviewed., Results: Pure endonasal and cervical endoscopic approaches still have some disadvantages, including the learning curve and the deeper surgical field. Endoscopically assisted transoral surgery with 30° endoscopes represents an emerging option to standard microsurgical techniques for transoral approaches to the anterior CVJ. This approach should be considered as complementary rather than an alternative to the traditional microsurgical transoral-transpharyngeal approach., Conclusions: The transoral approach with sparing of the soft palate still remains the gold standard compared with the pure transnasal and transcervical approaches because of the wider working channel provided by the former technique. The transnasal endoscopic approach alone appears to be superior when the CVJ lesion exceeds the upper limit of the inferior third of the clivus., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Several surgical approaches for the treatment of pathologies of the craniovertebral junction (CVJ) and high cervical regions have been reported. For the best postoperative results, selection of a surgical route to treat such pathologies should be based on a complete understanding of the approach., Case Description: A 64-year-old woman presented with a 5-year history of motor and sensory disturbances in her right upper extremity. Cervical magnetic resonance imaging (MRI) showed a slightly enhanced mass at the C2-C4 level. Sagittal T2-weighted MRI revealed a hyperintense dumbbell-shaped mass involving a damaged C3 vertebral body. We performed a 2-stage operation to achieve gross total removal of the tumor. In the first operation, a posterior approach was used to remove the intracanalicular tumor, achieve spinal cord decompression, and establish a histological diagnosis of the tumor (subsequently diagnosed as a chordoma). In the second operation, gross total removal of the chordoma was achieved via the anterior high cervical retropharyngeal approach. We used iliac bone and titanium plates for the bony fusion., Conclusions: Our results indicate that the high cervical retropharyngeal approach is a reasonable option for pathologies located in the anterior or anterolateral portions of high cervical regions. This approach is an alternative to the transoral approach to the ventral CVJ and high cervical regions., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: For many years, the microsurgical transoral approach has been accepted as the gold standard for anterior decompressions of the craniovertebral junction (CVJ). The introduction of the endoscopic endonasal approach (EEA) has gained wide recognition and overwhelming support in recent years, including for diseases of the CVJ. The aim of this study was to critically analyze and discuss all cases of CVJ diseases approached by means of an EEA so far reported in the literature, including our institutional experience consisting of 6 consecutive patients., Methods: Six consecutive patients affected by CVJ disease underwent an EEA. Three patients had a tumor (2 chordomas and 1 myeloma) and 3 had impressio basilaris., Results: Five patients had an uncomplicated postoperative course and 1 developed an intraoperative cerebrospinal fluid leak and subsequent meningitis and died 5 weeks after surgery. A total of 107 patients (including our 6) affected by CVJ disease and treated with EEA have been reported so far. Among these patients, cerebrospinal fluid leak was reported in 13 (12.4%), transient velopharyngeal incompetence in 6 (5.6%), postoperative epistaxis in 2 (1.86%), and respiratory dysfunction requiring a tracheostomy in 2 (1.86%). In our extended institutional series of more than 20 consecutive anterior decompressions for CVJ diseases (including transoral and transnasal microsurgical approaches), the only fatal complication was associated with EEA., Conclusions: On the basis of the reviewed literature and our personal experience, the reported increased safety of the EEA needs to be reassessed and discussed., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Skull base surgery needs advanced equipment and is performed at few public sector hospitals in India. For financial and infrastructure reasons, the facilities available are insufficient for the large number of poor patients who need this surgery., Methods: Neurologically deteriorating poor patients who failed to receive skull base surgery at overloaded public sector hospitals underwent surgery with basic neurosurgical instruments, using the available resources and indigenously designed instruments adhering to the basic principles of skull base surgery. Various lesions operated on in the study were analyzed based on their location and surgical approach., Results: Ninety-one skull base surgeries in 84 patients were performed during 2013-2015. There were 46 males and 38 females, with an average age of 35 years. Surgical treatment included surgery of the craniovertebral junction (n = 43) and lesions of the anterior skull base (n = 7), middle skull base (n = 10), and posterior skull base (n = 31). Lesions were operated on through anterior (n = 10), lateral (n = 14), and posterior and posterolateral (n = 67) skull base approaches., Conclusions: The facilities available in low-income countries such as India are insufficient to take care of poor patients who need skull base surgery. Indigenous innovations, use of the available resources, and interdisciplinary coordination help overcome the challenges of resource scarcity to a reasonable extent in many ill-equipped public sector hospitals for the safe and efficient management of many patients who need skull base surgery., (Copyright © 2017 Elsevier Inc. All rights reserved.)