Search

Surgery to expose the anterior occiptocervical junction (OCJ) is exacting, and optimal approaches are debatable. The close proximity of vital structures and difficult surgical access present a unique challenge to treat lesions in this area. Routine access to the upper anterior cervical spine remains limited. The authors present a modified retropharyngeal approach and instrumentation in order to resect an exceptionally rare atypical rhabdoid teratoid tumor involving the craniovertebral junction. The technical aspects of this approach in anatomical perspectives are discussed in this article.

Background: This study evaluated spring-assisted posterior vault expansion (SA-PVE) in children aged > 2 years with craniosynostosis and signs of high intracranial pressure (ICP)., Methods: We retrospectively analysed all consecutive patients aged > 2 years and operated with SA-PVE between 2018 and 2020 at the Craniofacial Center at Sahlgrenska University Hospital, Sweden. During the procedure, a circumferent occipital bone flap extending below the torcula was created and remained attached to the dura. Intracranial volumes (ICVs) were calculated from computed tomography (CT) images, and demographic data and information regarding symptoms and signs of high ICP were collected., Results: The study included eight patients [Crouzon/Pfeiffer (n = 4), multiple craniosynostosis (n = 3), and secondary synostosis (n = 1)]. Median age at SA-PVE was 3.8 years (range: 2.5-12.8 years), and springs were removed after a median of 5.5 months (range: 2.3-8.3 months). The median operating time was 164 min (range: 102-221 min), and estimated blood loss was 4.5 mL/kg body weight (range: 1.4-59.1 mL/kg body weight), with 50% of patients receiving a blood transfusion. The median increase in ICV was 206 cm3 (range: 122-344 cm3) representing an 18.7% increase (range: 7.9-24.1%; p = 0.01). We observed no major perioperative complications, and symptoms related to high ICP were improved or absent at clinical follow-up., Conclusion: These results demonstrated that SA-PVE involving creation of a large occipital bone flap including the torcula as a safe and effective surgical treatment in children aged >2 years with craniosynostosis and elevated ICP.

Objective: To evaluate the feasibility of a novel method for occipitocervical fixation (OCF) through the endonasal corridor., Methods: 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., Results: 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., Conclusions: 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., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

The occipitocervical junction is formed by the foramen magnum (FM) and the adjacent anatomical structures of the C1 and C2 vertebrae. The FM is formed anteriorly by the basilar part of occipital bone. Anterolaterally, it borders the occipital condyles and hypoglossal canal as well as the jugular foramen. Posteriorly, the FM is formed by the squamous part of the occipital bone with the internal occipital crest. In the midline, named landmarks at the anterior margin are the basion and, at the posterior margin, the opisthion. Vital anatomic structures are located in the FM or pass through. Among these are the medulla oblongata, meninges, anterior and posterior spinal arteries, vertebral arteries, and spinal roots of the accessory nerve. The FM is firmly anchored to the cervical canal via strong ligamentous support.Pathologies in this area can be of congenital, acquired, traumatic, neoplastic, or infectious origin, with the respective surgical indications and approaches depending on the nature and location of the pathology. If the pathology is occipitoatlantal, the occiput is usually involved in surgery. On the other hand, if the pathology is only at the level of C1-C2, surgery may be limited to these two vertebrae.In this section, we present the surgical management of exemplary congenital cases, and we discuss the complications and what needs to be done to deal with them., (© 2025. The Author(s).)

Epidermoid cysts are uncommon accounting for less than 1% of all intracranial tumors. Among them, giant intradiploic epidermoid cysts of the posterior fossa i.e. those exceeding 5 cm are an even rarer entity. Here we report on the complete resection of a 7 cm posterior fossa epidermoid cyst involving the occipital bone in a 32-year-old female presenting with an acute on chronic exacerbation of headaches and vertigo. Complete resection including the cyst wall is crucial in preventing recurrence and malignant transformation. We add to limited existing data by reporting on the first systematic review to date assessing 25 cases of giant epidermoid cysts of the posterior fossa to discuss presentation, clinical and radiographic features and definitive management strategies.

Background: Chondroblastoma is a rare, benign bone tumor originating from immature chondrocytes, typically found in the epiphyseal plates of long bones. Its occurrence in the skull, particularly the occipital bone, is extremely rare., Case Presentation: We report a 10-year-old girl presenting with paroxysmal dizziness, occipital pain, and a palpable mass. Imaging studies revealed an osteolytic lesion in the occipital bone with a multiloculated appearance, indicating a concomitant aneurysmal bone cyst. The patient underwent craniotomy with complete tumor excision. Postoperative follow-up showed no neurological deficits or complications and MRI confirmed no recurrence., Conclusion: This case highlights the rare presentation of occipital bone chondroblastoma and emphasizes the importance of early surgical intervention for positive outcomes in pediatric patients., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The objective of this study is to present the two cases of cervical hemivertebra and torticollis, and To describe technique and result of cervical hemivertebra resection and torticollis correction via a anterior-posterior surgical approach and occipitocervical fusion. Cervical hemivertebra, accompanied by abipartite atlas, agenesis of odontoid and C2 segmental type of vertebral artery (VA), is a rare, but complex congenital anomalies, associated with cervical scoliosis and occipitocervical instability. To the best of our knowledge, this is the first report on such congenital anomaly and deformity correction via anterior-posterior hemivertebra resection with occipitocervical fusion. Two patients were presented with torticollis due to congenital cervical hemivertebra accompanied by abipartite atlas, agenesis of odontoid and C2 segmental type of VA. Deformity correction was executed by an anterior-posterior hemivertebra resection and occipitocervical fusion with segment instrumentation. The treatment course was uneventful and clinical outcomes was favorable. The radiographs showed a satisfactory deformity correction with a well-balanced coronal and sagittal alignment. Hemivertebra resection with occipitocervical fusion could correct torticollis with satisfactory clinical and radiographical outcome.

Background: Craniofacial fibrous dysplasia (CFD) typically occurs in the facial bones and anterior cranial vault and can produce both disfigurement and functional limitations for patients disfigurement. Treatment consists of reducing the abnormal bone. Bone contouring can become challenging when the exposure does not extend to the corresponding normal contralateral structures for comparison or when normal landmarks are not available, which may compromise the overall aesthetic outcome. We describe a technique using dynamic mirroring to accurately contour the involved part of the cranium in a case of giant CFD., Observations: A 49-year-old male presented with a giant deforming fibrous dysplasia of the right mastoid and parieto-temporo-occiput that was causing functional limitations due to the size of the bony mass. This was managed with multidisciplinary bony reduction. Several neurovascular structures were in proximity to the areas of planned drilling of the expansile lesion, and dynamic mirroring of the uninvolved left skull was utilized to maximize safety and symmetry of reduction. High-speed drilling of the right occipital bone was performed until the navigation system alerted the surgeon that symmetric depth had been achieved. There were no complications from the procedure and this technique maximized the limits of symmetric reduction without significantly increasing surgical complexity or duration., Lessons: Dynamic mirroring of bony structures in the posterior cranium is not commonly employed in neurosurgical practice. This technique may help improve the aesthetic outcomes of bony reduction in craniofacial dysplasia and a variety of similarly managed bony lesions, contour cranioplasties, and in unilateral craniosynostosis surgery.

Chronic skin defects in the head, face and neck pose challenges for closure, especially after multiple surgeries or radiation therapy. We report the case of a woman in her 70s with a chronic occipital wound following squamous cell carcinoma resections, resulting in exposed skull bone. Despite various options, we successfully treated the 4 cm x 5 cm wound with a Kerecis fish skin graft (FSG), observing significant improvement within a week. The FSG promoted granulation tissue formation, enabling subsequent full-thickness skin grafting from the patient's groin. Complete wound closure was achieved within 2 weeks, indicating FSG's efficacy in complex wound management. Our experience highlights FSG's potential as a valuable tool in wound healing and reconstruction, particularly in challenging cases involving the head and neck., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Modifications of the pi craniectomy technique are meant to address the occipital bullet deformity of sagittal synostosis, but it is not clear whether they result in persistent improvement. The authors' purpose was to use morphometric analysis to determine whether a low occipital osteotomy with verticalization results in improved occipital shape after a modified pi procedure 2 years after surgery., Method: The authors performed a retrospective cohort study comparing modified pi technique with and without a low occipital osteotomy with verticalization immediately and 2 years after surgery relative to age-matched normal controls. The authors used anthropometric measures and population-level anatomical templates using the multivariate template construction script from advanced normalization tools for comparison between groups. A subgroup analysis was performed for severe occipital bullet deformity at presentation., Results: The authors observed stable improvement in the angle of the inferior occiput with the occipital remodeling modification that persisted 2 years after surgery. This improvement was seen in the entire cohort and was greater in the severe subgroup analysis. Complications and blood transfusion volumes were not different between the 2 techniques. The low occipital osteotomy group demonstrated improved posterior vertical height and cephalic index immediately after surgery, but these did not persist 2 years later., Conclusions: Occipital remodeling improves the bullet deformity but does not affect posterior vertical height 2 years after surgery. The authors recommend direct inferior occipital remodeling when using the pi technique for young patients with acute occipital incline angles and occipital constriction., Clinical Question/level of Evidence: Therapeutic, III., (Copyright © 2023 by the American Society of Plastic Surgeons.)

This case study presents a 47-year-old male who was diagnosed with Gorham-Stout syndrome (GSS) 10 years ago in the occipitocervical junction. The pathology caused the resorption of the suboccipital bone, clivus, foramen magnum, and C1-C3 laminae. After his first fusion attempt in 2010 using occipital plate-cervical lateral mass screws, he needed many revision surgeries either for the progression of the pathology or for instrumentation failure and wound healing problems. Eventually, a new occipital plate and cervical pedicle screws were applied to obtain the exact solution. The involvement of the craniovertebral junction in GSS may be challenging for spinal surgeons due to the inadequate bone reserve for stabilization. As lateral mass screws cannot provide a strong pull-out force, cervical pedicular screws may be used as the first choice for unstable cervical GSS cases.

Objective: To assess the impact of tumor extension into the occipital condyle (OC) in lower clival chordoma management and the need for occipito-cervical fusion (OCF)., Methods: A retrospective analysis was conducted on 35 patients with lower clival chordoma. The preoperative area of the intact OCs, Hounsfield units, and the integrity of the apical ligament and the tectorial membrane were assessed using preoperative imaging., Results: Seven (20%) patients were in the OCF group. The OCF group exhibited a higher prevalence of preoperative pain in the neck or head (P = 0.006), ligament absence (P = 0.022), and increased propensity for postoperative wound issues (P = 0.022) than the non-OCF group. The OCF group had less intact OCs (P < 0.001) and higher spinal instability neoplastic score (P = 0.002) than the non-OCF group. All patients with intact OCs < 60% underwent OCF, and those with OCs ≥ 70% were treated without OCF. Those with OCs between 60% and 69% underwent OCF if the ligaments were eroded, and did not undergo OCF if the ligaments were intact. Treatment strategies varied, with endoscopic endonasal approach alone being common. Radiation therapy was administered to 89% of patients. All 3 patients treated with OCF after tumor resection had wound issues; none treated with OCF before resection had wound issues. None developed atlanto-occipital instability. Survival rates did not significantly differ between groups., Conclusions: In the absence of mobility-related neck pain, patients with lower clival chordoma and intact OC ≥ 60%, intact apical ligament, and intact tectorial membrane, may not require OCF., (Copyright © 2024 Elsevier Inc. All rights reserved.)

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.)

Objective: Skull base chordomas are rare, locally osseo-destructive lesions that present unique surgical challenges due to their involvement of critical neurovascular and bony structures at the craniovertebral junction (CVJ). Radical cytoreductive surgery improves survival but also carries significant morbidity, including the potential for occipitocervical (OC) destabilization requiring instrumented fusion. The published experience on OC fusion after CVJ chordoma resection is limited, and the anatomical predictors of OC instability in this context remain unclear., Methods: PubMed and Embase were systematically searched according to the PRISMA guidelines for studies describing skull base chordoma resection and OC fusion. The search strategy was predefined in the authors' PROSPERO protocol (CRD42024496158)., Results: The systematic review identified 11 surgical case series describing 209 skull base chordoma patients and 116 (55.5%) who underwent OC instrumented fusion. Most patients underwent lateral approaches (n = 82) for chordoma resection, followed by midline (n = 48) and combined (n = 6) approaches. OC fusion was most often performed as a second-stage procedure (n = 53), followed by single-stage resection and fusion (n = 38). The degree of occipital condyle resection associated with OC fusion was described in 9 studies: total unilateral condylectomy reliably predicted OC fusion regardless of surgical approach. After lateral transcranial approaches, 4 studies cited at least 50%-70% unilateral condylectomy as necessitating OC fusion. After midline approaches-most frequently the endoscopic endonasal approach (EEA)-at least 75% unilateral condylectomy (or 50% bilateral condylectomy) led to OC fusion. Additionally, resection of the medial atlantoaxial joint elements (the C1 anterior arch and tip of the dens), usually via EEA, reliably necessitated OC fusion. Two illustrative cases are subsequently presented, further exemplifying how the extent of CVJ bony elements removed via EEA to achieve complete chordoma resection predicts the need for OC fusion., Conclusions: Unilateral total condylectomy, 50% bilateral condylectomy, and resection of the medial atlantoaxial joint elements were the most frequently described independent predictors of OC fusion in skull base chordoma resection. Additionally, consistent with the occipital condyle harboring a significantly thicker joint capsule at its posterolateral aspect, an anterior midline approach seems to tolerate a greater degree of condylar resection (75%) than a lateral transcranial approach (50%-70%) prior to generating OC instability.

Objective: This study aimed to examine the mechanism of occipital condyle fractures (OCFs), their clinical symptoms, computer tomography (CT) scan findings, treatment options, and classification., Methods: A retrospective analysis was conducted on 43 patients with OCFs who were admitted to our neurosurgery center between 2017 and 2023., Results: The investigation covered their clinical symptoms, CT scan results, and treatment outcomes. It was found that 25.6% of the patients suffered from severe craniocerebral injuries with Glasgow Coma Scale (GCS) scores of 3-8 points, 9.3% had moderate injuries with GCS scores of 9-12 points, and 65.1% exhibited mild injuries with GCS scores of 13-15 points. Of these patients, 90.7% showed improvement upon discharge, 4.7% succumbed to their injuries, and another 4.7% developed paraplegia. Symptoms indicative of OCF in individuals with CCJ injuries included neck pain, swelling, cranial nerve palsy, and posterior pharyngeal wall swelling. Frequently observed complications in OCF patients included cerebral contusion, occipital bone fractures, and skull base fractures. Employing thin-layer CT scans of the CCJ area, along with sagittal and coronal CT reconstructions, is essential for identifying OCFs. The fractures were classified into 3 types based on the Anderson-Montesano classification, which, when modified, provides enhanced treatment guidance., Conclusions: OCFs are predominantly present in cases of high-energy trauma, with high-resolution thin-layer CT scans serving as the preferred diagnostic method. The application of the modified Anderson-Montesano classification, distinguishing between stable and unstable fractures, facilitates the determination of suitable treatment strategies. Stable OCFs can be managed using a rigid neck brace, while unstable OCFs may require Halo-vest frame fixation or surgical intervention., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: Congenital anomalies of the atlanto-occipital articulation may be present in patients with Chiari malformation type I (CM-I). However, it is unclear how these anomalies affect the biomechanical stability of the craniovertebral junction (CVJ) and whether they are associated with an increased incidence of occipitocervical fusion (OCF) following posterior fossa decompression (PFD). The objective of this study was to determine the prevalence of condylar hypoplasia and atlas anomalies in children with CM-I and syringomyelia. The authors also investigated the predictive contribution of these anomalies to the occurrence of OCF following PFD (PFD+OCF)., Methods: The authors analyzed the prevalence of condylar hypoplasia and atlas arch anomalies for patients in the Park-Reeves Syringomyelia Research Consortium database who underwent PFD+OCF. Condylar hypoplasia was defined by an atlanto-occipital joint axis angle (AOJAA) ≥ 130°. Atlas assimilation and arch anomalies were identified on presurgical radiographic imaging. This PFD+OCF cohort was compared with a control cohort of patients who underwent PFD alone. The control group was matched to the PFD+OCF cohort according to age, sex, and duration of symptoms at a 2:1 ratio., Results: Clinical features and radiographic atlanto-occipital joint parameters were compared between 19 patients in the PFD+OCF cohort and 38 patients in the PFD-only cohort. Demographic data were not significantly different between cohorts (p > 0.05). The mean AOJAA was significantly higher in the PFD+OCF group than in the PFD group (144° ± 12° vs 127° ± 6°, p < 0.0001). In the PFD+OCF group, atlas assimilation and atlas arch anomalies were identified in 10 (53%) and 5 (26%) patients, respectively. These anomalies were absent (n = 0) in the PFD group (p < 0.001). Multivariate regression analysis identified the following 3 CVJ radiographic variables that were predictive of OCF occurrence after PFD: AOJAA ≥ 130° (p = 0.01), clivoaxial angle < 125° (p = 0.02), and occipital condyle-C2 sagittal vertical alignment (C-C2SVA) ≥ 5 mm (p = 0.01). A predictive model based on these 3 factors accurately predicted OCF following PFD (C-statistic 0.95)., Conclusions: The authors' results indicate that the occipital condyle-atlas joint complex might affect the biomechanical integrity of the CVJ in children with CM-I and syringomyelia. They describe the role of the AOJAA metric as an independent predictive factor for occurrence of OCF following PFD. Preoperative identification of these skeletal abnormalities may be used to guide surgical planning and treatment of patients with complex CM-I and coexistent osseous pathology.

Objective: The purpose of this study was to identify factors associated with fusion success among pediatric patients undergoing occiput-C2 rigid instrumentation and fusion., Methods: The Pediatric Spine Study Group registry was queried to identify patients ≤ 21 years of age who underwent occiput-C2 posterior spinal rigid instrumentation and fusion and had a 2-year minimum clinical and radiographic (postoperative lateral cervical radiograph or CT scan) follow-up. Fusion failure was defined clinically if a patient underwent hardware revision surgery > 30 days after the index procedure or radiographically by the presence of hardware failure or screw haloing on the most recent follow-up imaging study. Univariate comparisons and multivariable logistic regression analyses were subsequently performed., Results: Seventy-six patients met inclusion criteria. The median age at surgery was 9 years (range 1.5-17.2 years), and 51% of the cohort was male. Overall, 75% of patients had syndromic (n = 41) or congenital (n = 15) etiologies, with the most frequent diagnoses of Down syndrome (28%), Chiari malformation (13%), and Klippel-Feil syndrome (12%). Data were available to determine if there was a fusion failure in 97% (74/76) of patients. Overall, 38% (28/74) of patients had fusion failure (95% CI 27%-50%). Univariate analysis demonstrated that use of a rigid cervical collar postoperatively (p = 0.04) and structural rib autograft (p = 0.02) were associated with successful fusion. Multivariable logistic regression analysis determined that patients who had rib autograft used in surgery had a 73% decrease in the odds of fusion failure (OR 0.27, 95% CI 0.09-0.82; p = 0.02). Age, etiology including Down syndrome, instrumentation type, unilateral instrumentation, use of recombinant human bone morphogenetic protein, and other variables did not influence the risk for fusion failure., Conclusions: In this multicenter, multidisciplinary, international registry of children undergoing occiput-C2 instrumentation and fusion, fusion failure was seen in 38% of patients, a higher rate than previously reported in the literature. The authors' data suggest that postoperative immobilization in a rigid cervical collar may be beneficial, and the use of structural rib autograft should be considered, as rib autograft was associated with a 75% higher chance of successful fusion.

Rationale: Complications of rod migration into the occipital bone after upper cervical fusion are very rare. No other cases have been reported, especially when associated with destructive spondyloarthropathy (DSA). The purpose of this case report is to remind clinicians of the risk of rod migration in cervical spine surgery in patients with DSA and to provide information on its causes, countermeasures, and treatment., Patient Concern: This case report presents the clinical course of a 61-year-old female patient with chronic kidney disease that required hemodialysis., Diagnosis, Intervention, Outcomes: The patient was diagnosed DSA involving the cervical spine. Initial treatment involved a halo vest, followed by anterior cervical corpectomy and fusion spanning from C5 to Th1. However, subsequent complications, including C5 fractures, kyphotic cervical alignment, and rod migration into the occipital bone, lead to multistage surgical interventions. This case highlights the challenges in managing DSA, the significance of optimal fixation strategies, and the importance of accounting for potential alignment changes., Conclusion: The effective management of occipital bone erosion after posterior cervical spine surgery for destructive spondyloarthropathy necessitates meticulous fixation planning, proactive rod length adjustment, preoperative assessment of the occipital position, and consideration of the compensatory upper cervical range of motion to prevent migration-related issues., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Aim: To provide a comprehensive analysis for accurate screw size selection and insertion angle during surgical procedures., Material and Methods: In this retrospective study, a total of 120 patients participated, resulting in the analysis of 240 occipital condyles using coronal, sagittal, and axial planes on CT scans. Statistical evaluation was performed using the Wilcoxon rank-sum test, with p < 0.05 considered statistically significant., Results: The mean sagittal length and height were measured at 17.2 ± 1.7 mm and 9.1 ± 1.5 mm, respectively. The average condyle angle, a crucial factor for screw insertion, was assessed at 38.0 ± 5.5 mm in length, 19.6 ± 2.6 mm in width, and 9.5 ± 1.0 mm in height. Condyle height in the anterior and posterior hypoglossal canals was measured at 10.8 ± 1.4 mm and 9.0 ± 1.4 mm, respectively. Screw angle and condyle width were statistically smaller in females compared to the male population., Conclusion: The OC is a significant anatomical structure in the craniovertebral junction, playing a crucial role in stability. The obtained morphological values are applicable to the Turkish population and offer statistically significant findings for preoperative planning involving occipital condyle screw instrumentation.

When managing cranial bone flap infections, infected bone flaps are typically removed and subsequently replaced with artificial bones 6 to 12 months after the inflammation subsides. However, defects in the occipital region pose challenges due to concerns regarding brain protection when patients lie in the supine position. Herein, the authors report the case of a 73-year-old woman with an occipital bone flap infection, which was successfully managed by reconstruction with a trapezius musculocutaneous flap immediately after removing the infected bone flap. One year and 2 months postoperatively, the wound had fully healed, and the patient remained symptom-free without any complications, such as sunken flap syndrome. Soft tissue reconstruction using pedicled trapezius musculocutaneous flap is a viable strategy for managing occipital bone flap infections. This flap ensures stable blood flow and requires minimal vascular manipulation, thereby reducing operation time as the patient does not need to change position., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

Background: The hypoglossal canal is a dual bone canal at the cranial base near the occipital condyles. The filaments of the hypoglossal nerve pass through the canal. It also transmits the meningeal branch of the ascending pharyngeal artery, the venous plexus and meningeal branches of the hypoglossal nerve. The hypoglossal nerve innervates all the intrinsic and extrinsic muscles of the tongue except the palatoglossal and is fundamental in physiological functions as phonation and deglutition. A surgical approach to the canal requires knowledge of the main morphometric data by neurosurgeons., Methods: The present study was carried out on 50 adult dried skulls: 31 males: age range 18-85 years; 19 females: age range 26-79 years. The skulls came from the ''Leonetto Comparini'' Anatomical Museum. The skulls belonged to people from Siena (Italy) and its surroundings (1882-1932) and, therefore, of European ethnicity. The present study reports (a) the osteological variations in hypoglossal canal (b) the morphometry of hypoglossal canal and its relationship with occipital condyles. One skull had both the right and left hypoglossal canals occluded and, therefore, could not be evaluated. None of the skulls had undergone surgery., Results: We found a double canal in 16% of cases, unilaterally and bilaterally in 2% of cases. The mean length of the right and left hypoglossal canals was 8.46 mm. The mean diameter of the intracranial orifice and extracranial orifice of the right and left hypoglossal canals was 6.12 ± 1426 mm, and 6.39 ± 1495 mm. The mean distance from the intracranial end of the hypoglossal canal to the anterior and posterior ends of occipital condyles was 10,76 mm and 10,81 mm. The mean distance from the intracranial end of the hypoglossal canal to the inferior end of the occipital condyles was 7,65 mm., Conclusions: The study on the hypoglossal canal adds new osteological and morphometric data to the previous literature, mostly based on studies conducted on different ethnic groups.The data presented is compatible with neuroradiological studies and it can be useful for radiologists and neurosurgeons in planning procedures such as transcondilar surgery. The last purpose of the study is to build an Italian anatomical data base of the dimensions of the hypoglossal canal in dried skulls.., (© 2023. The Author(s).)

Indications Corridor and Limits of Exposure: The extreme lateral approach is useful for both extradural and intradural anterior and anterolateral lesions at the lower clivus down to the level of C2., Anatomic Essentials Need for Preoperative Planning and Assessment: The patient is evaluated with MRI, computed tomography (CT), and an angiogram. Special attention is given to vascular (vertebral artery course, dominance, tumor feeders) and bony (occipital condyle, jugular tubercle, foramen magnum and extent of bony involvement) anatomy., Essentials Steps of the Procedure: The patient is positioned lateral with the head flexed and tilted down without axial rotation. A hockey-stick incision is performed, and the myocutaneous flap is raised. A retrocondylar craniectomy is performed. The extradural vertebral artery is exposed for proximal control. A C1 hemilaminectomy is performed. Cephalad/caudal exposure and drilling of the occipital condyle are determined per case. The dura is opened, and the vertebral artery is released at the dural entry point to facilitate the tumor removal. The tumor is debulked and delivered inferoventrally away from the neuroaxis and cranial nerves. After removing the tumor, the dura is closed using an allograft.The patients consented to the procedure and to the publication of their images., Pitfalls/avoidance of Complications: • Cranial nerve deficits• Craniocervical instability• Postoperative hydrocephalus• Postoperative pseudomeningocele., Variants and Indications for Their Use: A transmastoid extension of the craniectomy allows access further rostrally in the clivus. For C1-2 chordomas, the approach is extended inferiorly, and the vertebral artery is mobilized out of the C1-2 transverse foramina. For tumors involving the joints, an occipitocervical stabilization is required.Images in video reused with permission as follows: image at 00:16 from Revuelta Barbero et al, Endoscopic endonasal transclival-medial condylectomy approach for resection of a foramen magnum meningioma: 2-dimensional operative video, Oper Neurosurg , 16(2), 2018, by permission from the Congress of Neurological Surgery; images at 00:30, and top image at 00:52 reused from Wen et al, Microsurgical anatomy of the transcondylar, supracondylar, and paracondylar extensions of the far-lateral approach, J Neurosurg , 87(4), 1997, with permission from JNSPG; bottom images at 00:52 from Muthukumar et al, A morphometric analysis of the foramen magnum region as it relates to the transcondylar approach, Acta Neurochir , 147(8), 2005, by permission from Springer Nature., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Objective: To provide a precise description of the morphology and morphometry of the hypoglossal canal (HC) and its relationship with surrounding structures by using the epoxy sheet plastination technique., Methods: Thirty human cadaveric heads were plastinated into 5 sets of gross transparent plastination slices and 43 sets of ultrathin plastination sections. The HC were examined at both macro- and micro levels in these plastination sections and the reconstructed 3-dimensional visualization model., Results: The HC was an upward arched bony canal with a dumbbell-shaped lumen. According to the arched trajectory of its bottom wall, the HC could be divided into a medial ascending segment and a lateral descending segment. The thickness of the compact bone in the middle part of the HC was thinner than that at the intracranial and extracranial orifices. In 14 of 43 sides (32.6%), the posterior wall or the roof of the HC were disturbed by passing venous channels which communicated the posterior condylar emissary vein and the inferior petroclival vein. The trajectory of hypoglossal nerve in HC is mainly from anterosuperior to posteroinferior. The meningeal dura and the arachnoid extended into the HC along the hypoglossal nerve to form the dural and arachnoid sleeves and then fused with the nerve near the extracranial orifice of the HC., Conclusions: Knowledge of the detailed anatomy of the HC can be helpful in avoiding surgical complications when performing surgery for lesions and the occipital condylar screw placement in this complex area., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: In economically undeveloped areas, surgery for basilar invagination (BI) is still a serious economic burden for people. This study introduces a modified interfacet technique for the treatment of BI using shaped autologous occipital bone mass to reduce BI and to save economical expenditure., Methods: The data of 6 patients with BI who underwent modified interfacet technique using shaped autologous occipital bone mass in our hospital from April 2020 to February 2021 were retrospectively analyzed. During the operation, osteotomy at the external occipital protuberance was performed using ultrasonic osteotome, followed by interfacet release and implantation of shaped autologous occipital bone mass to complete vertical reduction. The atlantodental interval (ADI), Chamberlain's line violation (CLV), clivo-axial angle (CXA) and cervico-medullary angle (CMA) were compared before and after surgery. Additionally, we observed implant stability during the follow-up period to assess the long-term success of the modified interfacet technique., Results: The surgical procedure was successful in all six patients, with no reported incidents of vascular injury, spinal cord injury, or dural tear. Following the operation, improvements were observed in the ADI, CLV, CXA, and CMA. Throughout the follow-up period, the implants remained stable, demonstrating no complications such as bone resorption of the autologous occipital bone mass, implant fracture, or displacement., Conclusion: The utilization of shaped autologous occipital bone mass in atlantoaxial interfacet bone grafting has demonstrated effectiveness and feasibility. This technique offers simplicity, ease of preparation, and cost-effectiveness, making it a viable option for treating BI., Competing Interests: Conflict of interest None., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Rationale: The synergistic effect between nonmalignant lesions can also cause a serious impact on patient survival. This disease involves different organ systems and presents with a variety of clinical manifestations, such as schwannoma, depigmentation, low-grade glioma, and skeletal abnormalities. We report a case of type I neurofibromatosis with an occipital bone defect., Patient Concerns: We report a case of a 50-year-old man with type I neurofibromatosis with occipital bone defect., Diagnosis: The patient was accepted by the local hospital due to sudden right upper limb weakness accompanied by jitter without recognizable cause or inducement. A computerized tomography scan at a local hospital suggested subcutaneous neurofibromatosis with a left occipital cranial defect with thinning bone. On admission physical examination, diffuse multiple masses could be seen throughout the body and head of different sizes and composed of soft and tough textures. The largest one was located in the posterior occipital bone, approximately 8*8 cm in size, with a child tumor and tough texture. Multiple café-au-lait spots could be found on the chest and back, and multiple freckles can be seen in the armpit. The patient underwent surgery. Postoperative pathology showed a spindle cell tumor, which was determined to be neurofibromatosis type I according to immunopathology and clinical data., Interventions: The patient was admitted for surgical treatment. During the operation, the scalp mass was completely abducted and the tumor tissue at the skull defect was sharply separated. Postoperative pathology showed that the peripheral margin and the bottom margin were cleaned., Outcomes: Computerized tomography and magnetic resonance imaging showed that the tumor was completely. There were not any surgical complications. The patient recovered well, was cured and was dismissed from the hospital., Lessons: The synergistic effect between nonmalignant lesions can also cause a serious impact on patient survival to encourage early medical intervention. The clinical presentation of neurofibromatosis type I am usually nonmalignant, and in this case, involvement of the skull with bone defect is very rare. Therefore, it is necessary to accumulate relevant cases, reveal the pathogenesis of the disease, predict the development and outcome, and provide more evidence for early therapeutic intervention of similar patients in the future., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

A congenital mastoid cholesteatoma (CMC) is a keratinizing epithelium originating from embryological epithelial tissue of the mastoid. It is often not diagnosed until it becomes large because of its rarity and indolent nature. Although there are a few reports on giant CMC, its exact extensions have not been well described, and detailed information regarding surgical methods is lacking, especially in giant CMC involving the occipital condyle and the middle and posterior cranial fossae. In this article, we report a case involving a 70-year-old woman with a giant CMC that extended inferiorly to the occipital condyle. The CMC eroded the middle and posterior cranial fossae, sigmoid sinus plate, and fallopian canal of the facial nerve. For complete removal, we used a subtotal petrosectomy in conjunction with an exposure of the cranial cervical junction and a wide decompression of the suboccipit. The boundaries of exposure were similar to those of a petro-occipital transsigmoid approach which is usually used for management of tumor involving the jugular foramen. The wide exposure allowed for complete removal of the lesion without any complications. Thus, we recommend this surgical approach for management of the giant CMC involving the occipital condyle and the middle and posterior cranial fossae.

To identify skull-base growth patterns in Crouzon syndrome, we hypothesized premature minor suture fusion restricts occipital bone development, secondarily limiting foramen magnum expansion., Skull-base suture closure degree and cephalometric measurements were retrospectively studied using preoperative computed tomography (CT) scans and multiple linear regression analysis., Evaluation of multi-institutional CT images and 3D reconstructions from Wake Forest's Craniofacial Imaging Database (WFCID)., Sixty preoperative patients with Crouzon syndrome under 12 years-old were selected from WFCID. The control group included 60 age- and sex-matched patients without craniosynostosis or prior craniofacial surgery., None., 2D and 3D cephalometric measurements., 3D volumetric evaluation of the basioccipital, exo-occipital, and supraoccipital bones revealed decreased growth in Crouzon syndrome, attributed solely to premature minor suture fusion. Spheno-occipital (β = -398.75; P  < .05) and petrous-occipital (β = -727.5; P  < .001) suture fusion reduced growth of the basioccipital bone; lambdoid suture (β = -14 723.1; P  < .001) and occipitomastoid synchondrosis (β = -16 419.3; P  < .001) fusion reduced growth of the supraoccipital bone; and petrous-occipital suture (β = -673.3; P  < .001), anterior intraoccipital synchondrosis (β = -368.47; P  < .05), and posterior intraoccipital synchondrosis (β = -6261.42; P  < .01) fusion reduced growth of the exo-occipital bone. Foramen magnum morphology is restricted in Crouzon syndrome but not directly caused by early suture fusion., Premature minor suture fusion restricts the volume of developing occipital bones providing a plausible mechanism for observed foramen magnum anomalies.

Purpose: Anatomical knowledge of the hypoglossal canal is very important in relation to drilling of occipital condyle, jugular tubercle etc. So, this study was conducted to identify various morphometric and morphological features of the hypoglossal canal and its distance from adjacent structures relative to stable and reliable anatomic landmarks., Methods: The study was performed on 142 hypoglossal canals of 71 adult human dry skulls. The parameters measured were the transverse, vertical diameter, depth of the hypoglossal canal. The distances from the hypoglossal canal to the foramen magnum, occipital condyle and jugular foramen were also noted. In addition, the different locations of the hypoglossal canal orifices in relation to the occipital condyle were assessed. The different shapes and types of the hypoglossal canal were also noted., Results: There was significant difference (p < 0.05) in measurements taken on the right and left sides in males and females. The intracranial orifice of hypoglossal canal was present in middle 1/3rd in 100% of occipital condyle for both genders. The extracranial orifice of the hypoglossal canal was found to be in the anterior 1/3rd in 99% and 93.7% for male and female, respectively. Simple hypoglossal canal with no traces of partition was found to be more in males and females. The most common shape noted was oval both in males and females (71.8% and 68.7% respectively)., Conclusion: The results of the dimensions of the hypoglossal canal and its distance from other bony landmarks will be helpful for neurosurgeons to plan which surgical approaches should be undertaken while doing various surgeries in posterior cranial fossa., (© 2023. The Author(s).)

Background: The far lateral approach has been developed to access lesions at the craniocervical junction and upper cervical spinal canal. Associated morbidity triggered the development of less invasive tailored approaches., Method: In this lateral approach to the craniocervical junction, the occipital condyle is kept intact, vertebral artery manipulation is minimized, and the sigmoid sinus is not skeletonized. A linear incision through skin and muscles and use of an abdominal wall fat graft minimize the risk of cerebrospinal fluid leakage., Conclusions: The exposure provided is sufficient for the majority of tumors in this region and allows for low complication rates., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Purpose: Odontoidectomy for ventral compressive pathology may result in O-C1 and/or C1-2 instability. Same-stage endonasal C1-2 spinal fusion has been advocated to eliminate risks associated with separate-stage posterior approaches. While endonasal methods for C1 instrumentation and C1-2 trans-articular stabilization exist, no hypothetical construct for endonasal occipital instrumentation has been validated. We provide an anatomic description of anterior occipital condyle (AOC) screw endonasal placement as proof-of-concept for endonasal craniocervical stabilization., Methods: Eight adult, injected cadaveric heads were studied for placing 16 AOC screws endonasally. Thin-cut CT was used for registration. After turning a standard inferior U-shaped nasopharyngeal flap endonasally, 4 mm × 22 mm AOC screws were placed with a 0° driver using neuronavigation. Post-placement CT scans were obtained to determine: site-of-entry, measured from the endonasal projection of the medial O-C1 joint; screw angulation in sagittal and axial planes, proximity to critical structures., Results: Average site-of-entry was 6.88 mm lateral and 9.74 mm rostral to the medial O-C1 joint. Average angulation in the sagittal plane was 0.16° inferior to the palatal line. Average angulation in the axial plane was 23.97° lateral to midline. Average minimum screw distances from the jugular bulb and hypoglossal canal were 4.80 mm and 1.55 mm., Conclusion: Endonasal placement of AOC screws is feasible using a 0° driver. Our measurements provide useful parameters to guide optimal placement. Given proximity of hypoglossal canal and jugular bulb, neuronavigation is recommended. Biomechanical studies will ultimately be necessary to evaluate the strength of AOC screws with plate-screw constructs utilizing endonasal C1 lateral mass or C1-2 trans-articular screws as inferior fixation points., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Aim: To determine a quantitative relationship between the postoperative clivus slope (CS) and the change in the Patient-Reported Japanese Orthopaedic Association (PRO-JOA) scores following reduction surgery of the basilar invagination (BI)., Material and Methods: A single center retrospective study was conducted. Patients who met the inclusion and exclusion criteria at our hospital during the period from August 2015 to August 2020 were identified. The CS was introduced. Radiographic parameters including the CS were measured to assess realignment preoperatively and postoperatively. The PRO-JOA score was recorded to reveal the clinical outcome. The PRO-JOA score and the radiographic parameters that included the CS were compared between postoperative BI patients., Results: Ninety-four patients with BI were included in the study. The CS (0.96, 0.93-1.00) was inversely correlated with the PROJOA score. The CS was negatively associated with the ΔPRO-JOA score in the crude model, while no significant associations in the fully adjusted model, although in the case of the latter, a slight trend was found (p for trend < < 0.05). In the non-linear model, the CS was negatively associated with the ΔPRO-JOA score in patients diagnosed with BI, unless the CS exceeded 63.4°., Conclusion: A reduction in the CS affects the postoperative PRO-JOA score of BI patients. This relationship can be employed as a quantitative reference in determining preoperative design with respect to the intraoperative correction needed to reduce craniovertebral junction deformity in BI.

Unilateral lambdoid synostosis is the rarest form of craniosynostosis. Surgical correction is technically challenging from a morphological standpoint and is used to decompress intracranial pressure. Herein, the authors present a "rotational advancement bone flap" technique for the repair of posterior plagiocephaly. A bicoronal skin incision was performed, to expose the occipital region. The rotational advancement bone flap was designed to hinge off the nonsynostotic side, and it was set up to include an occipital protrusion on the normal side. On the premature side, an advancement bone flap was set up to include the flattened and deformed occipital bone. A titanium cranial distractor, which was attached between the bone flap and the anterior bone. An absorbable plate, which would later become a hinge due to the movement of the bone flap, was attached to the area for reinforcement. The authors technique was able to decompress intracranial pressure with satisfactory esthetic outcomes., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)

Background: Occipito-cervical fixation (OCF) provides immediate rigid fixation to cranio-vertebral junction (CVJ); however, in current practice, the optimal occipito-cervical fixation method is arguable., Aim: The aim of this study was to test the safety and efficacy of a newly designed inside-outside occipital (OC) plate system for the treatment of cranio-vertebral junction instability., Material and Methods: Thirty-two patients of CVJ instability were treated using this new OC plate system. Safety and efficacy of this new OC plate was evaluated radiologically and clinically., Results: Follow-up period ranged from 9 to 23 months. During the follow-up, no implant failure, recurrent subluxation, or newly developed instability at adjacent levels occurred, except in one patient in whom C2 screw pullout occurred due to trauma. All patients showed a satisfactory fusion at three months follow-up examination., Conclusions: These preliminary results suggest that this OC plate system is a simple, safe, and effective method for providing immediate internal rigid fixation of the CV junction. Long-term results are needed to determine the superiority of this OC plate over other methods of occipital fixation., Competing Interests: None

This study aimed at quantifying trabecular volumetric bone mineral density (vBMD) at the external occipital protuberance (EOP) and the upper cervical spine. A retrospective review of patients who underwent non-contrast enhanced computed tomography of the cervical spine that included the occipital bone up to the EOP between 2007 and 2020 was conducted. Measurements of trabecular vBMD were performed in the occipital midline area, with the region of interest extending 4.5 mm above and below the center of the EOP, as well as the C1 lateral masses and the C2 vertebral body using asynchronous quantitative computed tomography. Eighty-six patients (female, 37.2%) were included for analysis. The patient population was 81.4% Caucasian with a mean ± SD age of 62.3 ± 13.1 years. Total bone thickness at the EOP was 16.7 ± 3.4 mm, with a ratio of trabecular to total bone thickness of 0.44. Trabecular vBMD (mean ± SD) was significantly higher at the EOP than at C1 and C2 (EOP = 612.3 ± 145.8 mg/cm 3 , C1 average = 290.3 ± 66.5 mg/cm 3 , C2 = 305.8 ± 78.8 mg/cm 3 ; p < 0.001). A significant strong correlation between trabecular vBMD of C1 and C2 was observed (r = 0.744; p < 0.001), but only low correlations between the EOP and C1 (r = 0.295; p = 0.008) and C2 (r = 0.413; p < 0.001). In individuals > 65 years of age, cervical vBMD was significantly lower, but remained high at the EOP. Clinical significance: Trabecular vBMD at the EOP is significantly higher than at the upper cervical vertebrae and remains high in older populations. Together with morphological information about the occipital bone, these results might be helpful for occipitocervical fixation when deciding about uni- or bicortical screw placement at the EOP., (© 2021 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

Background: The posterior condylar emissary vein (PCEV) and posterior condylar canal (PCC) are anatomical landmarks for identifying important structures like jugular tubercle and occipital condyle in surgical approach to the foramen magnum and condylar fossa. Several anatomical variations have been described. Drainage into the jugular bulb is found to be commonest., Method: A 70-year-old patient with unruptured vertebral artery-posterior inferior cerebellar artery (PICA) junction aneurysm-underwent surgical clipping via transcondylar fossa approach., Result: Preoperative computed tomography demonstrated an abnormal communication existed between the left-sided PCC and hypoglossal canal (HC). The PCEV was identified draining into a dilated venous channel/pouch at the "hip" of sigmoid sinus (junction of sigmoid sinus and jugular bulb). Intra-operatively, an occipital artery-PICA bypass was performed. The PCEV was skeletonized, coagulated, and divided to achieve hemostasis. The lateral and cranial drilling around PCC was successful at safeguarding the underlying contents of HC (in medial and caudal extent)., Conclusion: Preoperative angiography and detailed morphometric analysis of the PCC were helpful in planning surgical approach-identifying and controlling the PCEV, and skeletonization of the PCC without compromising the hypoglossal nerve and anterior condylar emissary vein., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Abstract: The posterior intraoccipital synchondrosis (PIOS) is a cartilaginous division separating the exoccipital and supraoccipital bones, allowing for flexibility of the cranial base at birth and which later ossifies in adolescence. The authors report a case of right PIOS synostosis that resembled right lambdoid synostosis, with left occipital bossing in a healthy, six-month-old female with an unremarkable birth history and no antecedent trauma. An initial referral was made from the pediatrician to oncology because of a concern over the presence and growth of a possible mass at the left occiput. Over 8 months, this mass grew and became more firm, accompanied by left occipital bossing and right occipital flattening. A computed tomography was obtained, which demonstrated the fusion of the PIOS, prompting a referral to plastic surgery. Cranial vault remodeling with switch cranioplasty was performed at age 14 months, complicated only by a superficial infection along the suture line. There are exceedingly few reports of PIOS synostosis, with occipital osteodiastasis related to birth trauma as the only prior explanation for this condition. With no birth trauma and delayed onset, our case likely represents idiopathic PIOS synostosis. With the many similarities in presentation, the surgical approaches commonly used for lambdoid synostosis, particularly switch cranioplasty, are suitable solutions to PIO synchondrosis with optimal functional and aesthetic outcomes., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)

Background: The intermediate condylar canal, which lies lateral to the occipital condyles and medial to the jugular foramen, is rarely mentioned in textbooks, even those devoted to the skull base. Therefore the present anatomic study was performed to better elucidate these structures., Methods: We studied 100 adult skulls (200 sides) to better understand the prevalence and anatomy of the intermediate condylar canal., Results: An intermediate canal was found on 6 of 200 sides (3%). On average, these canals traveled 7.1 mm lateral to the occipital condyle and had a mean of 2.2 mm posteromedial to the jugular foramen. Anteriorly, these canals opened into the external surface of the hypoglossal canal and, when present, were just medial to a paracondylar process for which there was a strong positive correlation. The length of the canals ranged from 5 to 7.8 mm. In all, there were 3 partial canals and 3 complete canals. One left canal communicated anteriorly at the confluence of the inferior opening of a septated (bifurcated) hypoglossal canal and an unnamed foramen medial to the jugular foramen. These canals were distinct from posterior condylar canals when the latter was present., Conclusions: Knowledge of the anatomic variants at the base of the skull may help minimize complications during surgical procedures that employ a paracondylar or transcondylar approach or approaches to the jugular foramen., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: Condylar screw fixation is a rescue technique and an alternative to the conventional configuration of occipitocervical fusion. Condylar screws are utilized when previous surgical bone removal along the supraocciput has occurred which makes anchoring of a traditional barplate technically difficult or impossible. However, the challenging dissection of C0-1 necessary for condylar screw fixation and the concerns about possible complications have, thus far, prevented the acquisition of large surgical series utilizing occipital condylar screws. In the largest case series to date, this paper aims to evaluate the safety profile and complications of condylar screw fixation for occipitocervical fusion., Methods: A retrospective safety and complication-based analysis of occipitocervical fusion via condylar screws fixation was performed., Results: A total of 250 patients underwent occipitocervical fusions using 500 condylar screws between September 2012 and September 2018. No condylar screw pullouts, or vertebral artery impingements were observed in this series. The sacrifice of condylar veins during the dissection at C0-1 did not cause any venous stroke. Hypotrophic condyles were found in 36.4% (91 of the 250) cases and did not prevent the insertion of condylar screws. Two transient hypoglossal deficits occurred at the beginning of this surgical series and were followed by recovery a few months later. Corrective strategies were effective in preventing further hypoglossal injuries., Conclusions: This surgical series suggests that the use of condylar screws fixation is a relatively safe and reliable option for OC fusion in both adult and pediatric patients. Methodical dissection of anatomical landmarks, intraoperative imaging, and neurophysiologic monitoring allowed the safe execution of the largest series of condylar screws reported to date. Separate contributions will follow in the future to provide details about the long-term clinical outcome of this series., (© 2021. The Author(s).)

Study Design: Retrospective descriptive study., Objective: The aim of this study was to create topographical maps of occipital bone thickness and venous sinus (VS) presence to assess the risks of screw insertion in four commercially available occipital plates., Summary of Background Data: Craniocervical junction instability and deformity are serious pathological conditions that require posterior fixation of the occipital bone to the cervical vertebrae. Insertion of occipital bone screws requires evaluation of both occipital bone thickness for effective internal fixation and intracranial VS presence for vascular injury prevention. Despite the surgical risks, there is a paucity of research on safe screw placement., Methods: We created a matrix of 231 standardized measurement points to analyze the occipital bone thickness and VS presence in cervical spine CT angiograms. These measurements were used to create topographical maps of occipital bone thickness and likelihood of VS presence, which we then compared to the screw hole configurations of four occipital plates., Results: Hundred patients were assessed. Maximum occipital bone thickness of 13.9 ± 3.3 mm was midline in the occipital bone, 45 mm from the foramen magnum, around the external occipital protuberance (EOP). Regions with thicknesses >8 mm were 2 cm lateral to the EOP at the level of the superior nuchal line and 2.5 cm inferior to the EOP. The area with the highest VS presence rate was around the EOP and the superior nuchal line. The right transverse VS was more prominent in both sexes., Conclusion: There is a limited area of the occipital bone with thicknesses for enough screw purchase. Previous studies have shown 8 mm as the minimum screw length to reduce the risk of implant failure. In our analysis, only "T"-shaped plates had configurations with thicknesses >8 mm for each screw hole. For every screw hole in the analyzed occipital plates, there was a possibility of VS presence ranging from 8% to 33%.Level of Evidence: 5., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Occipitocervical fusion is necessary for many pathologies of the craniocervical junction. The anatomy of the region is unique, and fusion can cause significant morbidity. This retrospective review aims to investigate the complication rates and outcomes of occipitocervical fixation., Material and Methods: This is a retrospective review of 128 patients with occipitocervical fixation operated between 1994 and 2020. The average follow-up is 63 months., Results: The indications of occipitocervical fixation were basilar invagination (53 patients; 41.4%), trauma (25 patients; 19.5%), tumor (23 patients; 18%), instability due to rheumatoid arthritis (13 patients; 10.2%), cervical deformity (7 patients; 5.5%) and os odontoideum (7 patients; 5.5%). There were six early postoperative (1st month) deaths. We observed complications in 67 patients (52%). Most common complication was implant-related (32%), followed by wound problems (23.4%), systemic and other complications (11.7%), neurologic complications (6.2%). Implants are removed in 31 patients (24%) for different reasons: deep wound infection (7), local pain and restriction of head movements (21), respiratory distress and swallowing problems (2), screw fracture and local pain (1)., Conclusions: Occipitocervical fixation has quite large number of complications and significantly restricts head movements. With the advent of our biomechanical concepts, indications should be limited, and shorter cervical fixations should be preferred., Level of Evidence: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: To evaluate the clinical efficacy and safety of the modified technique utilizing the occipital bicortical screws and plate system in occipitocervical revision surgery., Methods: Between October 2010 and May 2018, 12 consecutive patients were retrospectively evaluated. All patients had posterior occipitocervical resurgery utilizing modified technique of bicortical screws and occipital plate. The measurements of extracranial occiput on midline were conducted on computed tomography (CT) scans. The thickness of the occipital bone at the location of external occipital protuberance and below 15 mm were evaluated, respectively. For the procedure, the trajectory was drilled perpendicular to the external occipital protuberance for the specified depth with a depth-limited drilling, 2 mm away from the internal bone plate, then the trajectory was deepened at intervals of 1 mm each time until reaching the internal bone plate. Meanwhile, a probe was used to explore all the walls of the trajectory. Bicortical screws were inserted to the occipital plate and the depth of penetration was less than 2 mm from the internal bone plate. Clinical efficacy and radiographic evaluation were followed up., Results: The thickest point was the external occipital protuberance, which was 15.49 ± 1.47 mm and decreased gradually on the midline to 13.41 ± 1.60 mm at below 15 mm. Twelve cases (mean age 41.17 years; range, 24-62 years), including five males and seven females, were followed up for 24.08 months (14-32 months). The interval time was 40.42 months (3-156 months) after the initial operation. At the final follow-up, JOA score increased from 8.58 ± 2.53 before surgery to 12.67 ± 1.84 (P < 0.05) and VAS score improved from 6.17 ± 1.21 to 2.08 ± 1.32 (P < 0.05). Besides, clinical symptoms were relieved in all patients after revision surgery. All patients had rigid internal fixations with bone fusion and no major complications occurred., Conclusions: Posterior occipitocervical plate-screw system with bicortical screws had the advantages of safety, simple and promising efficacy without excessive tissue release or intraspinal manipulation, proving that it's valuable as a modified technique for occipitocervical revision surgery., (© 2021 The Authors. Orthopaedic Surgery published by Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.)

Objective: To propose a surgical approach algorithm for the tumors of the cervicothoracic spine., Methods: All patients operated for vertebral column tumors involving the occipito-cervicothoracic spine were reviewed. Oncologic characteristics and surgical approach were gathered. Approach was classified by the use of staging and trajectory (posterior, transnasal, transoral, transmandibular, transcervical, transsternal). Angle of attack was defined for the occipitocervical junction tumor as the angle inscribed by the inferior mandibular plane and line connecting the superior tumor pole and mandibular angle. For lesions extending below the thoracic inlet, angle of attack was that inscribed by the plane of the thoracic inlet and the line connecting the jugular notch and inferior tumor pole., Results: In total, 115 patients were included (mean age 56.7 years, 64 [56%] male, average size 26.5 cm 3 , 39 [34%] primary tumors). Sixty-nine (60%) of patients had single-stage procedures (57 [49.6%] posterior-only, 12 [10.4%] anterior-only), 35 (30.4%) had 2-stage procedures, and 11 (9.6%) had 3- or 4-stage approaches. Lesions requiring a combined transmandibular-transcervical approach all involved the C2 and C3 levels and had a significantly steeper angle of attack (42.5 ± 9.5 vs. 6.1 ± 13.3°; P = 0.01) and greater superior tumor extent above the inferior plane of the mandible (3.69 ± 2.18 vs. 0.33 ± 0.78; P = 0.002). Lateral tumor extent, tumor size, nor inferior angle of attack differed significantly between approach groups., Conclusions: Here, we present a preliminary decision-making algorithm for the management of vertebral column tumors of the cervicothoracic spine. Based on this single-center experience, we suggest which patients, assessed via a combination of tumor histology and regional anatomy, may benefit from extended anterior surgical access., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Craniocervical injuries (CCJs) account for 10% to 30% of all cervical spine trauma. An increasing number of patients are surviving these injuries due to advancements in automobile technology, resuscitation techniques, and diagnostic modalities. The leading injury mechanisms are motor vehicle crashes, falls from height, and sports-related events. Current treatment with urgent rigid posterior fixation of the occiput to the cervical spine has resulted in a substantial reduction in management delays expedites treatment of CCJ injuries. Within CCJ injuries, there is a spectrum of instability, ranging from isolated nondisplaced occipital condyle fractures treated nonoperatively to highly unstable injuries with severely distracted craniocervical dissociation. Despite the evolution of understanding and improvement in the management of cases regarding catastrophic failure to diagnose, subsequent neurologic deterioration still occurs even in experienced trauma centers. The purpose of this article is to review the injuries that occur at the CCJ with the accompanying anatomy, presentation, imaging, classification, management, and outcomes., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)