Comparative analysis of deep-learning-based bone age estimation between whole lateral cephalometric and the cervical vertebral region in children.

Bone age determination in individuals is important for the diagnosis and treatment of growing children. This study aimed to develop a deep-learning model for bone age estimation using lateral cephalometric radiographs (LCRs) and regions of interest (ROIs) in growing children and evaluate its performance. This retrospective study included 1050 patients aged 4-18 years who underwent LCR and hand-wrist radiography on the same day at Pusan National University Dental Hospital and Ulsan University Hospital between January 2014 and June 2023. Two pretrained convolutional neural networks, InceptionResNet-v2 and NasNet-Large, were employed to develop a deep-learning model for bone age estimation. The LCRs and ROIs, which were designated as the cervical vertebrae areas, were labeled according to the patient's bone age. Bone age was collected from the same patient's hand-wrist radiograph. Deep-learning models trained with five-fold cross-validation were tested using internal and external validations. The LCR-trained model outperformed the ROI-trained models. In addition, visualization of each deep learning model using the gradient-weighted regression activation mapping technique revealed a difference in focus in bone age estimation. The findings of this comparative study are significant because they demonstrate the feasibility of bone age estimation via deep learning with craniofacial bones and dentition, in addition to the cervical vertebrae on the LCR of growing children.

Anatomical study of the C6 pedicle and lateral mass in children aged 0-14 years based on CT imaging.

OBJECTIVE: This study aims to investigate the anatomical structure of the C6 pedicle and lateral mass in children aged 0-14 years using CT imaging, providing detailed insights into their growth and development. METHODS: We conducted a comprehensive measurement of C6. Measurements included width, length, and height of the pedicles, as well as the length, width, and thickness of the lateral masses, and several angular metrics. Regression analysis was performed to understand the growth trends, and statistical analyses were carried out to identify differences between age groups, genders, and sides. RESULTS: In children younger than four years, the pedicle width exceeds its height, influencing the diameter of the pedicle screws. By age two to three, the pedicle height and lateral mass thickness reaches 3.0 mm, allowing for the use of 3.0 mm diameter screws. The pedicle transverse angle remains stable. Most parameters showed no significant differences between the left and right sides. Size parameters exhibited significant larger in males than females at ages 0-1, 3-7, and 10-12 years. Regression analysis revealed that the growth trends of size parameters follow cubic or polynomial curves. Most angular metrics follow cubic fitting curves without a clear trend of change with age. CONCLUSION: This study provides a detailed analysis of the anatomical development of the C6 pedicle and lateral masses in children, offering valuable insights for pediatric cervical spine surgeries. The findings highlight the importance of considering age-specific anatomical variations when planning posterior surgical fixation, specifically at C6. It is necessary for us to perform thin-layer CT scans on children and carefully measure various indicators before surgery.

From medical imaging to 3D printed anatomical models: a low-cost, affordable 3D printing approach.

OBJECTIVE: To share our experience in creating precise anatomical models using available open-source software. METHODS: An affordable method is presented, where from a DICOM format of a computed tomography, a segmentation of the region of interest is achieved. The image is then processed for surface improvement and the DICOM format is converted to STL. Error correction is achieved and the model is optimized to be printed by stereolithography with a desktop 3D printer. RESULTS: Precise measurements of the dimensions of the DICOM file (CT), the STL file, and the printed model (3D) were carried out. For the C6 vertebra, the dimensions of the horizontal axis were 55.3 mm (CT), 55.337 mm (STL), and 55.3183 mm (3D). The dimensions of the vertebral body were 14.2 mm (CT), 14.551 mm (STL), and 14.8159 mm (3D). The length of the spinous process was 18.2 mm (CT), 18.283 mm (STL), and 18.2266 mm (3D), while its width was 8.5 mm (CT), 8.3644 mm (STL), and 8.3226 mm (3D). For the C7 vertebra, the dimensions of the horizontal axis were 58.6 mm (CT), 58.739 mm (STL), and 58.7144 mm (3D). The dimensions of the vertebral body were 14 mm (CT), 14.0255 mm (STL), and 14.2312 mm (3D). The length of the spinous process was 18.7 mm (CT), 18.79 mm (STL), and 18.6458 mm (3D), and its width was 8.9 mm (CT), 8.988 mm (STL), and 8.9760 mm (3D). CONCLUSION: The printing of a 3D model of bone tissue using this algorithm is a viable, useful option with high precision.

OBJETIVO: Compartir nuestra experiencia para crear modelos anatómicos precisos utilizando software con licencia abierta disponibles. MÉTODOS: Se presenta un método asequible, en donde a partir de un formato DICOM de una tomografía computarizada se logra una segmentación de la región de interés. Posteriormente se procesa la imagen para una mejora de superficie y se realiza la conversión de formato DICOM a STL. Se logra la corrección de errores y se optimiza el modelo para luego ser impreso por medio de estereolitografía con una impresora 3D de escritorio. RESULTADOS: Se efectuaron mediciones precisas de las dimensiones del archivo DICOM (TC), del archivo STL y del modelo impreso (3D). Para la vértebra C6, las dimensiones del eje horizontal fueron 55.3 mm (TC), 55.337 mm (STL) y 55.3183 mm (3D). Las dimensiones del cuerpo vertebral fueron 14.2 mm (TC), 14.551 mm (STL) y 14.8159 mm (3D). La longitud de la apófisis espinosa fue de 18.2 mm (TC), 18.283 mm (STL) y 18.2266 mm (3D), mientras que su ancho fue de 8.5 mm (TC), 8.3644 mm (STL) y 8.3226 mm (3D). Para la vértebra C7, las dimensiones del eje horizontal fueron 58.6 mm (TC), 58.739 mm (STL) y 58.7144 mm (3D). Las dimensiones del cuerpo vertebral fueron 14 mm (TC), 14.0255 mm (STL) y 14.2312 mm (3D). La longitud de la apófisis espinosa fue de 18.7 mm (TC), 18.79 mm (STL) y 18.6458 mm (3D), y su ancho fue de 8.9 mm (TC), 8.988 mm (STL) y 8.9760 mm (3D). CONCLUSIÓN: La impresión de un modelo en 3D de tejido óseo mediante este algoritmo resulta una opción viable, útil y con una alta precisión.

Anatomical description of a new ligamentous supporting structure of the canine cranial cervical spinal cord.

The cranial cervical vertebral column carries a unique range of mobility with the addition of dorsal and ventral flexion and rotation. The denticulate ligaments provides support and protection of the spinal cord, but little is known of the adaption of this apparatus at the cranial cervical portion of the spinal cord. We present in this publication a new pair of ligaments in dogs that supports the spinal cord inside the vertebral canal at the level of the C1-C2 spinal segments.

The vertical topography of the carotid bifurcation - original study and review.

PURPOSE: The vertical level of carotid bifurcation (CB) is commonly indicated at the superior margin of the thyroid cartilage. Few studies observed the CB vertical topography. It was aimed at studying the vertical location of the CB as referred to vertebral and anterior cervical landmarks. METHODS: An archived lot of 147 computed tomography angiograms was documented for the vertical level of CB referred to vertebral and anterior cervical landmarks. The topography of the CB in relation to anterior landmarks was classified into seven types: (1) at the superior margin of the thyroid cartilage; (2) between the hyoid and the thyroid cartilage; (3) at the hyoid level; (4) between the hyoid and mandible; (5) subgonial or supragonial CB; (6) lower cervical level; (7) intrathoracic. RESULTS: The most common locations of CB were at C3 (27.21%), C3/C4 (26.19%) and C4 (25.51%). Bilateral symmetry of CB was found in 51.7%, except for C2 and C5/C6. Type 7 was not found, type 3 occurred in 39.12%, type 2 in 24.49%, type 1 in 13.95%, type 4 in 13.61%, type 5 in 6.12%, and type 6 in 2.72% (294 CBs). Bilateral symmetry of anterior types was found in 59.86%. Statistically significant correlations were found between sex and both left and right types and vertebral levels of CB. CONCLUSIONS: The vertical topography of the CB is highly variable and has sex-related specificity. This detail should be included in the teaching of anatomy. Surgeons and interventionists should better document the carotid anatomy on a case-by-case basis.

Anatomy and mobility in the adult cadaveric craniocervical junction.

Genetic diseases with craniofacial malformations can be associated with anomalies of the craniocervical joint (CCJ). The functions of the CCJ are thus impaired, as mobility may be either limited by abnormal bone fusion causing headaches, or exaggerated in the case of hypermobility, which may cause irreparable damage to the spinal cord. Restoring the balance between mobility and stability requires surgical correction in children. The anatomy and biomechanics of the CCJ are quite unique, yet have been overlooked in the past decades. Pediatric evidence is so scarce, that investigating the adult CCJ is our best shot to disentangle the form-function relationships of this anatomical region. The motivation of the present study was to understand the morphological and functional basis of motion in the CCJ, in the hope to find morphological features accessible from medical imaging able to predict mobility. To do so, we have quantified the in-vitro kinematics of the CCJ in nine cadaveric asymptomatic adults, and estimated a wide range of mobility variables covering the complexity of spinal motion. We compared these variables with the shape of the occipital, the atlas and the axis, obtained using a dense geometric morphometric approach. Morphological joint congruence was also quantified. Our results suggest a strong relationship between bone shape and motion, with the overall geometry predicting best the primary movements, and the joint facets predicting best the secondary movements. We propose a functional hypothesis stating that the musculoligamental system determines movements of great amplitude, while the shape and congruence of joint facets determine the secondary and coupled movements, especially by varying the geometry of bone stops and the way ligaments are tensioned. We believe this work will provide valuable insights in understanding the biomechanics of the CCJ. Furthermore, it should help surgeons treating CCJ anomalies by enabling them to translate objectives of functional and clinical outcome into clear objectives of morphological outcome.

Morphometric Analysis of the Neural Arch of C2 Vertebra in Indian Population.

BACKGROUND AND OBJECTIVE: The most common injuries to upper cervical spine are fractures of the second cervical vertebrae. The study aims to evaluate the morphometry of the neural arch of the second cervical vertebrae in the South Indian population. MATERIALS AND METHODS: Sixty-three second cervical vertebrae of undetermined gender and age without any gross defect were used for the study. The dimensions of neural arch, including superior articular facet, inferior articular facet, pediculoisthmic component, lamina, spinous process, foramen transversarium, and vertebral foramen, were measured by two independent observers using digital vernier caliper accurate to 0.1 mm and the data was analyzed. Descriptive statistics were obtained for the variables. Paired t-test was done to compare the measurements between right and left sides. RESULTS: There was no statistical difference between the right and left sides of the dimensions of superior articular facets, foramen transversarium, and the transverse diameter of inferior articular facet. The anteroposterior diameter of the inferior articular facets was more on the right side (P = 0.009). The width of the pediculoisthmic component in both the superior and inferior aspects was found to be less on the right side than that of the left (P = 0.006 and P = 0.031, respectively). The thickness in the middle one-third of laminae was optimum for bilateral safe screw insertion (≥4.0 mm) in 77% specimens. CONCLUSION: In summary, measurements of the transverse diameter of superior articular facet and thickness of lamina differed significantly from those reported in literature. This should be kept in mind while doing neurosurgery procedures in the Indian population.

The Late Cretaceous eutherian Zalambdalestes reveals unique axis and complex evolution of the mammalian neck.

The typical mammalian neck consisting of seven cervical vertebrae (C1-C7) was established by the Late Permian in the cynodont forerunners of modern mammals. This structure is precisely adapted to facilitate movements of the head during feeding, locomotion, predator evasion, and social interactions. Eutheria, the clade including crown placentals, has a fossil record extending back more than 125 million years revealing significant morphological diversification in the Mesozoic. Yet very little is known concerning the early evolution of eutherian cervical morphology and its functional adaptations. A specimen of Zalambdalestes lechei from the Late Cretaceous of Mongolia boasts exceptional preservation of an almost complete series of cervical vertebrae (C2-C7) revealing a highly modified axis (C2). The significance of this cervical morphology is explored utilizing an integrated approach combining comparative anatomical examination across mammals, muscle reconstruction, geometric morphometrics and virtual range of motion analysis. We compared the shape of the axis in Zalambdalestes to a dataset of 88 mammalian species (monotremes, marsupials, and placentals) using three-dimensional landmark analysis. The results indicate that the unique axis morphology of Zalambdalestes has no close analog among living mammals. Virtual range of motion analysis of the neck strongly implies Zalambdalestes was capable of exerting very forceful head movements and had a high degree of ventral flexion for an animal its size. These findings reveal unexpected complexity in the early evolution of the eutherian cervical morphology and suggest a feeding behavior similar to insectivores specialized in vermivory and defensive behaviors in Zalambdalestes akin to modern spiniferous mammals.

Anatomy of the craniocervical junction - A review.

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.

Magnetic resonance imaging-based classification of the myodural bridge complex and its influencing factors.

Cerebrospinal fluid (CSF) circulation is considered the third circulation of the human body. Recently, some scholars have proposed the myodural bridge (MDB) as a novel power source for CSF flow. Moreover, the suboccipital muscles can exert a driving force on the CSF via the MDB. This hypothesis is directly supported by head rotation and nodding movements, which can affect CSF circulation. The MDB has been validated as a normal structure in humans and mammals. In addition, the fusion of MDB fibers of different origins that act in concert with each other forms the MDB complex (MDBC). The MDBC may be associated with several CSF disorder-related neurological disorders in clinical practice. Therefore, the morphology of the MDBC and its influencing factors must be determined. In this study, T2-weighted imaging sagittal images of the cervical region were analyzed retrospectively in 1085 patients, and magnetic resonance imaging (MRI) typing of the MDBC was performed according to the imaging features of the MDBC in the posterior atlanto-occipital interspace (PAOiS) and posterior atlanto-axial interspace (PAAiS). The effects of age and age-related degenerative changes in the cervical spine on MRI staging of the MDBC were also determined. The results revealed four MRI types of the MDBC: type A (no MDBC hyposignal shadow connected to the dura mater in either the PAOiS or PAAiS), type B (MDBC hyposignal shadow connected to the dura mater in the PAOiS only), type C (MDBC hyposignal shadow connected to the dura mater in the PAAiS only), and type D (MDBC hyposignal shadow connected to the dura mater in both the PAOiS and PAAiS). The influencing factors for the MDBC typing were age (group), degree of intervertebral space stenosis, dorsal osteophytosis, and degenerative changes in the cervical spine (P < 0.05). With increasing age (10-year interval), the incidence of type B MDBC markedly decreased, whereas that of type A MDBC increased considerably. With the deepening of the degree of intervertebral space stenosis, the incidence of type C MDBC increased significantly, whereas that of type A MDBC decreased. In the presence of dorsal osteophytosis, the incidence of type C and D MDBCs significantly decreased, whereas that of type A increased. In the presence of protrusion of the intervertebral disc, the incidence of type B, C, and D MDBCs increased markedly, whereas that of type A MDBC decreased considerably, with cervical degenerative changes combined with spinal canal stenosis. Moreover, the incidence of both type C and D MDBCs increased, whereas that of type A MDBC decreased. Based on the MRI signal characteristics of the dural side of the MDBC, four types of the MDBC were identified. MDBC typing varies dynamically according to population distribution, depending on age and cervical degeneration (degree of intervertebral space stenosis, vertebral dorsal osteophytosis formation, simple protrusion of intervertebral disc, and cervical degeneration changes combined with spinal canal stenosis, except for the degree of protrusion of the intervertebral disc and the degree of spinal canal stenosis); however, it is not influenced by sex.

Computed Tomography-Based Morphometric Analysis of Lower Cervical Anterior Transpedicular Screw Fixation and Related Factors in the Chinese Population.

BACKGROUND: Anterior transpedicular screw (ATPS) internal fixation of the lower cervical spine is an alternative for patients who cannot tolerate combined anterior and posterior surgery. The cervical vertebral anatomy varies with many factors, including age, gender, height, weight, and race. METHODS: Three-dimensional (3D) CT reconstructions were performed on 122 patients. We selected the best level and measured the relevant parameters on both sides of the cervical vertebrae. RESULTS: We identified the entry point and orientation parameters of ATPS fixation for the C3-C7 vertebrae, and analyzed cervical pedicle parameters. Outer pedicle width (OPW), outer pedicle height (OPH), and pedicle axis length (PAL) were not correlated with body weight and age, but were positively correlated with body height (P < 0.05). After multiple linear regression analysis to exclude the effects of body height, no significant differences in OPW, OPH, and PAL were found between male and female subjects at most cervical levels. Pedicle cortical thickness was negatively correlated with age (P < 0.05). The percentage of pedicles with OPW <4.5 mm was: C3, 38.10%; C4, 34.92%; C5, 12.70%; C6, 9.52%; and C7, 0%. The percentage of pedicles with OPWs ≤4.5 mm, ≤4.0 mm, and ≤3.5 mm was higher among subjects with body height <160 cm. CONCLUSIONS: This study presents the internal anatomy of the cervical spine and provides accurate preoperative evaluation data for ATPS fixation. OPW, OPH, and PAL are positively correlated with body height, while pedicle cortical thickness is negatively correlated with age.

Reinterpretation of tuberculate cervical vertebrae of Eocene birds as an exceptional anti-predator adaptation against the mammalian craniocervical killing bite.

We report avian cervical vertebrae from the Quercy fissure fillings in France, which are densely covered with villi-like tubercles. Two of these vertebrae stem from a late Eocene site, another lacks exact stratigraphic data. Similar cervical vertebrae occur in avian species from Eocene fossils sites in Germany and the United Kingdom, but the new fossils are the only three-dimensionally preserved vertebrae with pronounced surface sculpturing. So far, the evolutionary significance of this highly bizarre morphology, which is unknown from extant birds, remained elusive, and even a pathological origin was considered. We note the occurrence of similar structures on the skull of the extant African rodent Lophiomys and detail that the tubercles represent true osteological features and characterize a distinctive clade of Eocene birds (Perplexicervicidae). Micro-computed tomography (µCT) shows the tubercles to be associated with osteosclerosis of the cervical vertebrae, which have a very thick cortex and much fewer trabecles and pneumatic spaces than the cervicals of most extant birds aside from some specialized divers. This unusual morphology is likely to have served for strengthening the vertebral spine in the neck region, and we hypothesize that it represents an anti-predator adaptation against the craniocervical killing bite ("neck bite") that evolved in some groups of mammalian predators. Tuberculate vertebrae are only known from the Eocene of Central Europe, which featured a low predation pressure on birds during that geological epoch, as is evidenced by high numbers of flightless avian species. Strengthening of the cranialmost neck vertebrae would have mitigated attacks by smaller predators with weak bite forces, and we interpret these vertebral specializations as the first evidence of "internal bony armor" in birds.

Study on articular surface morphology of atlantoaxial lateral mass based on differential manifold.

OBJECTIVES: To propose a surface reconstruction algorithm based on a differential manifold (a space with local Euclidean space properties), which can be used for processing of clinical images and for modeling of the atlantoaxial joint. To describe the ideal anatomy of the lateral atlantoaxial articular surface by measuring the anatomical data. METHODS: Computed tomography data of 80 healthy subjects who underwent cervical spine examinations at our institution were collected between October 2019 and June 2022, including 46 males and 34 females, aged 37.8 ± 5.1 years (28-59 years). A differential manifold surface reconstruction algorithm was used to generate the model based on DICOM data derived by Vision PACS system. The lateral mass articular surface was measured and compared in terms of its sagittal diameter, transverse diameter, articular surface area, articular curvature and joint space height. RESULTS: There was no statistically significant difference between left and right sides of the measured data in normal adults (P > 0.05). The atlantoaxial articular surface sagittal diameter length was (15.83 ± 1.85) and (16.22 ± 1.57) mm on average, respectively. The transverse diameter length of the articular surface was (16.29 ± 2.16) and (16.49 ± 1.84) mm. The lateral articular surface area was (166.53 ± 7.69) and (174.48 ± 6.73) mm2 and the curvature was (164.03 ± 5.27) and (153.23 ± 9.03)°, respectively. The joint space height was 3.05 ± 0.11mm, respectively. There is an irregular articular space in the lateral mass of atlantoaxial, and both upper and lower surfaces of the articular space are concave. A sagittal plane view shows that the inferior articular surface of the atlas is mainly concave above; however, the superior articular surface of the axis is mainly convex above. In the coronal plane, the inferior articular surface of the atlas is mostly concave above, with most concave vertices located in the medial region, and the superior articular surface of the axis is mainly concave below, with most convex vertices located centrally and laterally. CONCLUSION: A differential manifold algorithm can effectively process atlantoaxial imaging data, fit and control mesh topology, and reconstruct curved surfaces to meet clinical measurement applications with high accuracy and efficiency; the articular surface of the lateral mass of atlantoaxial mass in normal adults has relatively constant sagittal diameter, transverse diameter and area. The distance difference between joint spaces is small, but the shape difference of articular surfaces differs greatly.

A novel radiographic analysis system for subaxial cervical spine pedicle screw placement.

BACKGROUND: Precise pedicle screw placement of the subaxial cervical spine is difficult. Not every hospital is equipped with a guidance system that can provide effective help. Computed tomography (CT) scanning is almost a routine preoperative examination for cervical spine surgery in all hospitals. Appropriate measurement and analysis of the CT images could assist optimal cervical pedicle screw placement. The purpose of this study is to propose a new and universal method using computed tomography (CT) morphological parameters analysis to assist optimal cervical pedicle screw placement from C3 to C7. METHODS: A localization system with six parameters was designed based on preoperative CT reconstruction to guide subaxial cervical spine pedicle screw placement. The six parameters were distance from the starting point to the midline [D1], distance from the starting point to the lower edge of the inferior articular process [D2], transverse section angle [TSA], sagittal section angle [SSA], pedicle width [PW], and pedicle height [PH]. The six parameters were analyzed in 53 participants. RESULTS: Combining D1 and D2 could localize the entrance of the pedicle screw, and we concluded that D1 and TSA and D2 and SSA could be a new standard for determination of the transverse and sagittal orientation of the pedicle screw. The six parameters were closely related to the patient's gender, height, and weight. PH and PW were linearly correlated and could guide selection of the appropriate pedicle screw. SSA was an independent parameter of the relevant vertebral body, and changes in SSA had nothing to do with the curvature or posture of the cervical spine. CONCLUSIONS: Understanding and applying the six-parameter localization system are essential for achieving accurate and optimal pedicle screw placement in subaxial cervical spine, regardless of cervical sagittal alignment.

Evaluation of Head and Cervical Spine Posture after Therapy with Maxillary Protraction Appliances / Evaluación de la Postura de la Cabeza y la Columna Cervical Después de la Terapia con Aparatos de Protracción Maxilar

SUMMARY: The objective of this study was to evaluate the changes of head and cervical spine posture of skeletal class malocclusion in adolescent with maxillary protraction. Thirty cases of skeletal class malocclusion were randomly selected from the Stomatological Hospital of Shanxi Medical University. High-quality lateral cephalograms were collected including pre- and posttreatment to compare the changes of head and cervical spine posture. Data were processed using SPSS 26.0 statistical software. The paired-t test was used to compare pre- and posttreatment mean angular measurements.A significant difference in the SNA(p<0.001), SNB(p<0.01), and ANB(p<0.001) between T1 and T2 showed an improvement in the sagittal relationships. A significant change was observed in middle cervical spine posture, while upper cervical spine posture variables showed no significant difference after treatment. Skeletal class with maxillary protraction appliance not only led to the improvement of sagittal relationship, but also changed the middle cervical spine posture.

El objetivo de este estudio fue evaluar los cambios en la postura de la cabeza y la columna cervical debido a la maloclusión clase esquelética en adolescentes con protracción maxilar. Treinta casos de maloclusión de clase esquelética fueron seleccionados al azar del Hospital Estomatológico de la Universidad Médica de Shanxi. Se recogieron cefalogramas laterales de alta calidad, incluidos el tratamiento previo y posterior, para comparar los cambios en la postura de la cabeza y la columna cervical. Los datos se procesaron con el software estadístico SPSS 26.0. Se utilizó la prueba t pareada para comparar las medidas angulares medias antes y después del tratamiento. Una diferencia significativa en SNA (p <0,001), SNB (p <0,01) y ANB (p <0,001) entre T1 y T2 mostró una mejora en las relaciones sagitales. Se observó un cambio significativo en la postura de la columna cervical media, mientras que las variables de postura de la columna cervical superior no mostraron diferencias significativas después del tratamiento. La clase esquelética con aparato de protracción maxilar no solo condujo a la mejora de la relación sagital, sino que también cambió la postura de la columna cervical media.

An anatomical study of the suboccipital cavernous sinus and its relationship with the myodural bridge complex.

The suboccipital cavernous sinus (SCS) and the myodural bridge complex (MDBC) are both located in the suboccipital region. The SCS is regarded as a route for venous intracranial outflow and is often encountered during surgery. The MDBC consists of the suboccipital muscles, nuchal ligament, and myodural bridge and could be a power source for cerebrospinal fluid circulation. Intracranial pressure depends on intracranial blood volume and the cerebrospinal fluid. Since the SCS and MDBC have similar anatomical locations and functions, the aim of the present study was to reveal the relationships between them and the detailed anatomical characteristics of the SCS. The study involved gross dissection, histological staining, P45 plastination, and three-dimensional visualization techniques. The SCS consists of many small venous sinuses enclosed within a thin fibrous membrane that is strengthened by a fibrous arch closing the vertebral artery groove. The venous vessels are more abundant in the lateral and medial portions of the SCS than the middle portion. The middle and medial portions of the SCS are covered by the MDBC. Type I collagen fibers arranged in parallel and originating from the MDBC terminate on the SCS either directly or indirectly via the fibrous arch. The morphological features of SCS revealed in this research could serve as an anatomical basis for upper neck surgical procedures. There are parallel arrangements of type I collagen fibers between the MDBC and the SCS. The MDBC could change the blood volume in the SCS by pulling its wall during the head movement.

A new juvenile sauropod specimen from the Middle Jurassic Dongdaqiao Formation of East Tibet.

Jurassic strata are widely distributed in the eastern part of Tibet Autonomous Region, and have yielded many dinosaur bones. However, none of these specimens has been studied extensively, and some remain unprepared. Here we provide a detailed description of some new sauropod material, including several cervical vertebrae and a nearly complete scapula, recovered from the Middle Jurassic of Chaya County, East Tibet. The cervical vertebrae have short centra that bear ventral midline keels, as in many non-neosauropod sauropods such as Shunosaurus. Moreover, the cervical centra display deep lateral excavations, partitioned by a septum. The scapula has proximal and distal ends that are both expanded as in mamenchisaurids and neosauropods. However, relatively small body size and lack of fusion of neurocentral sutures in the cervical vertebrae suggest that the available material is from a juvenile, and the length of the cervical centra may have increased relative to the size of the rest of the skeleton in later ontogenetic stages. Phylogenetic analysis provides limited evidence that the new Tibetan sauropod specimen belongs to Eusauropoda, being more derived than Shunosaurus, but is basal to Mamenchisauridae. The new material provides important information on the morphological transition between Shunosaurus and mamenchisaurids, and extends the known biogeographic range of early-diverging sauropods in the Middle Jurassic of East Asia.

Morphometric Study of Sub Axial Cervical Spine Pedicles in Nepalese Population.

BACKGROUND: Mal-positioning of cervical screws risks neurovascular injury so, it is necessary to understand cervical pedicle morphology for pedicle screw fixation in the region. The risks of pedicle screw insertion in the cervical spine can be mitigated by a three-dimensional appreciation of pedicle anatomy. The study aims to determine the morphology of the sub axial cervical spine pedicles in Nepalese Population based on computerized tomography. METHODS: A cross-sectional study using computerized tomography scans of the spine was made among the randomly selected 87 patients who had visited National Trauma center, Kathmandu, Nepal with vertebral fracture other than cervical vertebrae. Patient was examined as per Advanced Trauma Life support protocol and neurological assessment. Measurement was done from the third cervical vertebra down to the seventh cervical vertebra in computer with standard software in the department of radiology from where all the computerized tomography scan reporting are done. RESULTS: The mean pedicle length ranged from 4.41 mm at C3 to 4.96 mm at C7 where mean pedicle height ranged from 4.64 at C3 to 5.12 at C7. Pedicle length, pedicle height and pedicle width were observed to be statistically significant with gender. The pedicle axial length of C3 and C7 vertebra were found significant with gender. All parameters were found to be greater in male compared to female. CONCLUSIONS: The study revealed that pedicle length, pedicle height, pedicle width, pedicle axial length increased from third to seventh cervical however, transverse angulation increased up to fifth vertebra and decreased to seventh vertebra.

Morphology analysis of the C2 pediculoisthmic component and feasibility of safe C2 pedicle screw placement: comparison of multiplanar reconstruction versus traditional radiographic methods.

BACKGROUND: Preoperatively evaluating the feasibility of safe C2 pedicle screw placement is the key to avoiding iatrogenic vertebral artery injury. However, it has not been verified whether the conventional CT measurements of C2 pediculoisthmic component (PIC) are reliable and accurate, and the results may lack validity. The purpose of this study is to analyze the evaluative performance of conventional CT measurements and to create an accurate predictor of morphometrics of C2 PIC. METHODS: A total of 304 C2 PICs were measured in 152 consecutive patients who underwent CT examination of the cervical spine between April 2020 and December 2020. We obtained the morphometric parameters of C2 PIC by measuring minimum PIC diameter (MPD) in CT multiplanar reconstruction versus conventional measurements of transverse PIC width (TPW), oblique PIC width (OPW) and definition of high-riding vertebral artery (HRVA). The outer diameter measured less than 4 mm in MPD was regarded as the standard of precluding safe C2 pedicle screw insertion. The evaluative performance of the conventional CT measurements was assessed, and the correlation between conventional CT measurements and measurements in CT multiplanar reconstruction was calculated. RESULTS: The parameters in OPW and MPD were measured significantly larger than those in TPW, and the preclusion of C2 pedicle screw placement evaluated from TPW and HRVA was significantly higher than that evaluated from OPW and MPD. The sensitivity of TPW was 93.09%, and the specificity was 79.31%. The sensitivity and specificity of OPW were 97.82% and 82.76%. The sensitivity of HRVA was 88.36%, and the specificity was 96.55%. Strong agreement with the highest correlation coefficient (0.879) and determination coefficient (0.7720) suggested that the outer diameter of OPW could be useful for the precise prediction of MPD. CONCLUSIONS: CT MPR allows accurate measurement of the narrowest section of the C2 PIC. The outer diameter of OPW could be simply measured and be useful for precise prediction of MPD, which makes C2 pedicle screw placement more safely than the conventional measurement of TPW and HRVA.

Morphometric study and anatomical variation with its incidence of foramina transversaria on the lower cervical vertebrae / Estudio morfométrico y variación anatómica con la incidencia de forámenes transversos en las vértebras cervicales inferiores

SUMMARY: Anatomical variation of the foramina transversaria (FT) is associated with vertebral neurovascular symptoms and can cause complications after lower spine surgery, especially cervical pedicle screw (CPS) insertion. FT variation has been documented and classified in various populations, as this information can help increase cervical stability in subaxial vertebral surgery. Although the morphometry of the upper cervical spine in Thai populations has been reported, there have yet been no studies examining the features of FT. The FT of dried cervical spines (C3-C7; left and right side; n = 107, male = 53 and female = 54) were examined for morphological variation, and their anteroposterior (AP) and transverse (T) diameters were measured using a digital vernier caliper. Morphometric data and variations were compared by sex and lateral side. It was that the C3-C6 FT in both sexes were round, and the C7 FT was elliptical with an oblique right side. FT diameters did not differ significantly by sex except for the AP diameters of C6-C7 and for T diameters of C4 and C7. The left AP diameters of C3-C6 were significantly longer than the right, as were the T diameters of C4 and C7 FT. Additionally, T diameter was significantly longer than that of the AP, except that of the left C6 in male spines, which did not differ from the AP. Most FT examined were round. These findings should be considered in the provisional diagnosis of vertebral neurovascular symptoms caused by FT variation as well as that of neurovascular damage after cervical pedicle screw placement.

La variación anatómica del foramen transverso (FT) se asocia con síntomas neurovasculares vertebrales y puede causar complicaciones después de la cirugía de columna cervical inferior, especialmente la inserción de tornillos pediculares cervicales (TPC). La variación del FT se ha documentado y clasificado en varias poblaciones, ya que esta información puede ayudar a aumentar la estabilidad cervical en la cirugía vertebral subaxial. Aunque se ha informado sobre la morfometría de la columna cervical superior en poblaciones tailandesas, aún no se han realizado estudios que examinen las características de FT. Se examinó la variación morfológica del FT de vértebras cervicales secas (C3-C7; lado izquierdo y derecho; n = 107, hombres = 53 y mujeres = 54), y se midieron sus diámetros anteroposterior (AP) y transverso (T) usando un pie de metro digital. Se compararon datos morfométricos y variaciones por sexo y lado. Los FT de C3-a C6 en ambos sexos eran redondos, y el FT C7 era elíptico con el lado derecho oblicuo. Los diámetros del FT no difirieron significativamente por sexo excepto para los diámetros AP de C6- C7 y para los diámetros transversos de C4 y C7. Los diámetros AP izquierdos de C3-C6 eran significativamente más largos que los del lado derecho, al igual que los diámetros transversos de C4 y C7. Además, el diámetro transverso fue significativamente mayor que el AP, excepto el C6 izquierdo en las vértebras de hombres, que no difirió del AP. La mayoría de los FT examinados eran redondos. Estos hallazgos deben ser considerados en el diagnóstico provisional de síntomas neurovasculares vertebrales causados por la variación del FT, así como en el de daño neurovascular tras la colocación de tornillos pediculares cervicales.