Traumatic atlanto-occipital dislocation with successfully bystander resuscitation after cardiopulmonary arrest: A case report.

This case report describes successful bystander cardiopulmonary resuscitation after a cardiopulmonary arrest due to a traffic accident, followed by early diagnosis and treatment of a traumatic atlanto-occipital dislocation, resulting in successful community reintegration.

Clinical characteristics of upper cervical spine injuries in children: a retrospective case series.

OBJECTIVE: Pediatric cervical spine injuries (CSI) can be devastating, and children < 8 years are particularly at risk for upper CSI given unique anatomical differences. Diagnosis of these injuries can be delayed due to variable clinical presentations and a paucity of existing literature. The authors aimed to characterize the spectrum of pediatric upper CSI. METHODS: This was a retrospective, single-center case series of trauma patients aged < 16 years who were assessed at a level I pediatric trauma center and diagnosed with upper CSI between 2000 and 2020. Patients were included if they had evidence of bony or ligamentous injury from the occiput to C2 on imaging or autopsy. Data were obtained from manual chart review and analyzed using descriptive statistics. RESULTS: In total, 502 patients were screened and 202 met inclusion criteria. Of these, 31 (15%) had atlanto-occipital (AO) joint distractions, 10 (5%) had atlanto-axial (AA) joint distractions, 31 (15%) had fractures of C1-2, and 130 (64%) had ligamentous injury without joint distraction. Of the patients with AO injury, 15 patients had complete dislocation. They presented as hemodynamically unstable with signs of herniation and 14 died (93%). In contrast, 16 had incomplete dislocation (subluxation). They usually had stable presentations and survived with good outcomes. Of the patients with AA injury, 2 had complete dislocation, presented with arrest and signs of herniation, and died. In contrast, 8 patients with subluxation mostly presented as clinically stable and all survived with little residual disability. The most common fractures of C1 were linear fractures of the lateral masses and of the anterior and posterior arches. The most common fractures of C2 were synchondrosis, hangman, and odontoid fractures. Overall, these patients had excellent outcomes. Ligamentous injuries frequently accompanied other brain or spine injuries. When these injuries were isolated, patients recovered well. CONCLUSIONS: Among upper CSI, AO and AA joint injuries emerged as particularly severe with high mortality rates. Both could be divided into complete dislocations or incomplete subluxations, with clear clinical differences and the former presenting with much more severe injuries. Lateral cervical spine radiography should be considered during resuscitation of unstable trauma patients to assess for these CSI subtypes. Fractures and ligamentous injuries were clinically heterogeneous, with presentations and outcomes depending on severity and associated injuries.

C2 Superior Facetal Osteotomy: A Novel Technique in Complex Craniovertebral Junction Surgery for C1 Lateral Mass Screw Placement.

Complex craniovertebral junction (CVJ) defects account for a considerable proportion of CVJ diseases. Given the heavily assimilated C1, an unfavorable C1-C2 joint orientation, an overriding C2 superior facet, a low-hanging occiput, and an abnormal vertebral artery course with a high-riding vertebral artery, placement of C1 lateral mass screws might be difficult. To address this, a novel technique for placing C1 lateral mass screws that avoid vertebral artery injury, low-hanging occiput, and overriding C2 superior facet was developed in this study. This approach enables firm fixation of C1-C2 even in difficult situations where the placement of the C1 lateral mass is challenging.

Geometric and Inertial Properties of the Pig Head and Brain in an Anatomical Coordinate System.

Porcine models in injury biomechanics research often involve measuring head or brain kinematics. Translation of data from porcine models to other biomechanical models requires geometric and inertial properties of the pig head and brain, and a translationally relevant anatomical coordinate system (ACS). In this study, the head and brain mass, center of mass (CoM), and mass moments of inertia (MoI) were characterized, and an ACS was proposed for the pre-adolescent domestic pig. Density-calibrated computed tomography scans were obtained for the heads of eleven Large White × Landrace pigs (18-48 kg) and were segmented. An ACS with a porcine-equivalent Frankfort plane was defined using externally palpable landmarks (right/left frontal process of the zygomatic bone and zygomatic process of the frontal bone). The head and brain constituted 7.80 ± 0.79% and 0.33 ± 0.08% of the body mass, respectively. The head and brain CoMs were primarily ventral and caudal to the ACS origin, respectively. The mean head and brain principal MoI (in the ACS with origin at respective CoM) ranged from 61.7 to 109.7 kg cm2, and 0.2 to 0.6 kg cm2, respectively. These data may aid the comparison of head and brain kinematics/kinetics data and the translation between porcine and human injury models.

Craniovertebral Junction Instability after Oncological Resection: A Narrative Review.

The craniovertebral junction (CVJ) is a complex transition area between the skull and cervical spine. Pathologies such as chordoma, chondrosarcoma and aneurysmal bone cysts may be encountered in this anatomical area and may predispose individuals to joint instability. An adequate clinical and radiological assessment is mandatory to predict any postoperative instability and the need for fixation. There is no common consensus on the need for, timing and setting of craniovertebral fixation techniques after a craniovertebral oncological surgery. The aim of the present review is to summarize the anatomy, biomechanics and pathology of the craniovertebral junction and to describe the available surgical approaches to and considerations of joint instability after craniovertebral tumor resections. Although a one-size-fits-all approach cannot encompass the extremely challenging pathologies encountered in the CVJ area, including the possible mechanical instability that is a consequence of oncological resections, the optimal surgical strategy (anterior vs posterior vs posterolateral) tailored to the patient's needs can be assessed preoperatively in many instances. Preserving the intrinsic and extrinsic ligaments, principally the transverse ligament, and the bony structures, namely the C1 anterior arch and occipital condyle, ensures spinal stability in most of the cases. Conversely, in situations that require the removal of those structures, or in cases where they are disrupted by the tumor, a thorough clinical and radiological assessment is needed to timely detect any instability and to plan a surgical stabilization procedure. We hope that this review will help shed light on the current evidence and pave the way for future studies on this topic.

Reference values of four measures of craniocervical stability using upright dynamic magnetic resonance imaging.

PURPOSE: To establish reference ranges for four most commonly used diagnostic measures of craniocervical instability (CCI) in three cervical sagittal positions. This necessitated development of a reliable measurement protocol using upright, dynamic MRI (udMRI), to determine differences in the extent of motion between positions, and whether age and sex correlate with these measures. MATERIALS AND METHODS: Deidentified udMRIs of 50 adults, referred for reasons other than CCI, were captured at three positions (maximal flexion, maximal extension and neutral). Images were analyzed, providing measures of basion-axial interval, basion-axial angle, basion-dens interval (BDI) and the Grabb-Oakes line (GOL) for all three positions (12 measures per participant). All measures were independently recorded by a radiologist and neurosurgeon to determine their reliability. Descriptive statistics, correlations, paired and independent t-tests were used. Mean (± 2 SD) identified the reference range for all four measures at each craniocervical position. RESULTS: The revised measurement protocol produced inter-rater reliability indices of 0.69-0.97 (moderate-excellent). Fifty adults' (50% male; mean age 41.2 years (± 9.7)) reference ranges for all twelve measures were reported. Except for the BDI and GOL when moving between neutral and full flexion, significant extents of movement were identified between the three craniocervical positions for all four measures (p ≤ 0.005). Only a minor effect of age was found. CONCLUSIONS: This is the first study to provide a rigorous standardized protocol for four diagnostic measures of CCI. Reference ranges are established at mid and ends of sagittal cervical range corresponding to where exacerbations of signs and symptoms are commonly reported.

Anterior atlanto-occipital transarticular screw fixation: a biomechanical comparison with posterior fixation techniques.

OBJECTIVE: Atlanto-occipital instability is commonly treated with posterior fixation. However, in patients with congenital or acquired factors, posterior fixation may not be possible. For these situations, a novel anterior atlanto-occipital transarticular screw (AATS) fixation technique has been introduced recently. However, biomechanical study of this technique is lacking. This study was designed to evaluate the biomechanical stability of AATS fixation for the atlanto-occipital joint and compare it with conventional posterior occipitocervical fixation (POCF). METHODS: Six cadaveric specimens (occiput-C4) were tested in four conditions, including intact, injury, injury + AATS, and injury + POCF states. A pure moment of 1.5 Nm was applied to specimens in flexion, extension, lateral bending, and axial rotation. The range of motion (ROM) and neutral zone (NZ) were calculated and compared from the occiput to C1. RESULTS: The AATS fixation constrained ROMs to 0.4° in flexion (p < 0.001), 0.4° in extension (p < 0.001), 1.0° in lateral bending (p < 0.001), and 0.7° in axial rotation (p < 0.001) when compared with the injury state. In all directions, there was no statistically significant difference observed in ROMs and NZs between AATS fixation and POCF (p > 0.05). CONCLUSIONS: This study identified that the novel AATS fixation, as stand-alone anterior fixation, was equivalent to POCF in all directions. The results suggest that anterior transarticular screw fixation is a biomechanically effective salvage technique for posterior atlanto-occipital fixation, and may also serve as supplemental fixation.

CT diagnosis of pituitary abscess, suppurative meningitis, and atlanto-occipital septic arthritis in a pony.

A 15-year-old pony was presented for acute neurological signs. Neurological examination suggested a brainstem lesion, blood laboratory tests detected an active inflammatory process, and upper respiratory endoscopy identified a suppurative lesion at the dorsal aspect of the right guttural pouch. Computed tomography was performed and findings were consistent with pituitary abscess, meningitis, and atlanto-occipital joint septic arthritis. Imaging findings were confirmed based on cerebrospinal and synovial fluid cultures and necropsy. Computed tomography provided important information for identifying the cause of the patient's neurological signs and helped the owner make a final decision for euthanasia.

Effect Sizes for Changes in Health and Well-Being Following Treatment With the One-To-Zero Technique in Individuals With Occipito-Atlantal Joint Dysfunction: A Repeated Measures Study.

Objectives: The purpose of this study was to determine effect sizes (ES) for changes in self-reported measures of musculoskeletal pain and dysfunction resulting from the one-to-zero method using a repeated measures study design. Methods: Twenty participants presenting with articular dysfunction of the occipito-atlantal (C0-C1) complex were treated using the one-to-zero method, a high-velocity low-amplitude thrust administered between the C0-C1 complex before treating other restrictive segments in a cephalocaudal direction. The participants completed online questionnaires using Google Forms that assessed aspects of the biopsychosocial model of pain at baseline and within a week after treatment. The questionnaires included the following: (1) Demographic and Health Behavior Survey; (2) Neck Bournemouth Questionnaire (NBQ) or Neck Disability Index (NDI); (3) Beck Anxiety Index (BAI); (4) Insomnia Severity Index (ISI); and (5) 36-Item Short Form Health Survey (SF-36). Paired t test or Wilcoxon signed ranks test was performed, dependent on normality. Cohen's d values were calculated for each questionnaire score (0.20 indicative of small; ≥0.50 medium; and ≥0.80 large ES). Results: The NDI, NBQ, BAI, and ISI had a large ES (all d ≥ 0.80). In the SF-36, 4 subscales had a small to near-medium ES, 1 subscale had a medium to near-large ES, and the remaining 2 had a large ES (d ≥ 0.80). The physical and mental component summary had a large (d = 0.88) and small ES (d = 0.35), respectively. Conclusion: The effect sizes suggest the one-to-zero treatment induces change in various aspects of the biopsychosocial model.

The ligament of barkow is a solid structure in human fetuses / O ligamento de barkow é uma estrutura individualizada em fetos humanos / El ligamento de barkow es una estructura individualizada en fetos humanos

ABSTRACT: Objective: The present study aims to dissect and identify the Barkow ligament (LB) in fetal specimens and describe its anatomical characteristics to contribute to its knowledge in the pediatric population and the clinical and surgical application of conditions associated with the Craniovertebral Junction (CVJ). ). Methods: This work evaluated 19 human fetuses aged 28-38 weeks. Of these, six specimens constituted the final sample and were studied through detailed dissections using coronal sections in an anterior approach up to the region described by the LB. Results: In all specimens, a thin fibrous band was found, horizontal and anterior to the axis tooth, with bilateral fixation on the occipital condyles, corroborating the results found for describing LB in adults. Conclusion: The LB is a congenital ligament that resists the extension of the atlantooccipital joint and may play a role in the stability of the CVJ. Level of Evidence III; Diagnostic Study.

RESUMO: Objetivo: O presente estudo tem como objetivo dissecar e identificar o ligamento de Barkow (LB) em espécimes fetais, e descrever suas caraterísticas anatômicas visando contribuir para o seu conhecimento em população pediátrica e na aplicação clínica e cirúrgica das condições associadas à Junção Craniovertebral (JCV). Métodos: Esse trabalho avaliou 19 fetos humanos de 28-38 semanas de vida. Destes, 6 espécimes constituíram a amostra final e foram estudados através de dissecções minuciosas utilizando secções coronais, em uma abordagem anterior, até a região de descrição do LB. Resultados: Em todos os espécimes foi encontrada uma delgada banda fibrosa, de disposição horizontal e anterior ao dente do áxis, com fixação bilateral nos côndilos occipitais, corroborando com os resultados encontrados para a descrição do LB em adultos. Conclusão: O LB é um ligamento congênito, que resiste a extensão da articulação atlantoccipital, e que pode ter papel na estabilidade da JCV. Nível de Evidência III; Estudo diagnóstico.

RESUMEN: Objetivo: El presente estudio tiene como objetivo diseccionar e identificar el ligamento de Barkow (LB) en especímenes fetales, y describir sus características anatómicas con el fin de contribuir a su conocimiento en la población pediátrica y en la aplicación clínica y quirúrgica de las condiciones asociadas a la unión craneovertebral. (UCV).). Métodos: Este trabajo evaluó 19 fetos humanos de entre 28 y 38 semanas. De estos, 6 ejemplares constituyeron la muestra final y fueron estudiados mediante disecciones detalladas mediante cortes coronales, en abordaje anterior, hasta la región descrita por el LB. Resultados: En todos los ejemplares se encontró una delgada banda fibrosa, horizontal y anterior al diente axis, con fijación bilateral en los cóndilos occipitales, corroborando los resultados encontrados para la descripción de LB en adultos. Conclusión: El LB es un ligamento congénito, que resiste la extensión de la articulación atlantooccipital, y que puede desempeñar un papel en la estabilidad de la UCV. Nivel de Evidencia III; Estudio Diagnóstico.

The Effectiveness of Intraarticular Cervical Facet Steroid Injections in the Treatment of Cervicogenic Headache: Systematic Review and Meta-analysis.

BACKGROUND: Cervicogenic headache (CGH) can often be difficult to treat, given the overlapping clinical features of other headaches and the varying sources of pain that patients report. While imaging is not useful in diagnosing CGH, anesthetic blockade of the atlanto-occipital joint, lateral atlantoaxial joint, or specific cervical zygapophyseal joints can be used to confirm the diagnosis. When conservative treatment measures, such as physical therapy, fail, interventional techniques, such as intraarticular steroid injections, have been shown in observational studies to provide relief in some patients. OBJECTIVES: To determine the efficacy of intraarticular cervical facet steroid injections in the treatment of CGH. STUDY DESIGN: Systematic review and meta-analysis. METHODS: We conducted a comprehensive search of Ovid Medline, Embase, Cochrane Central Register of Controlled Trials , Cumulative Index to Nursing and Allied Health Literature Plus with Full Text, Scopus, and the Web of Science platform, from inception to April 2021, for studies using intraarticular cervical facet injections to treat CGH in adults aged 18 or older. Primary outcomes included mean postinjection pain scores. Outcomes were pooled using a random effects model and reported as mean differences (MD) with 95% confidence intervals (CI). RESULTS: Three studies with a total of 64 patients met the inclusion criteria. According to data from each of the included studies, intraarticular cervical facet injections were shown to demonstrate improvement in the mean pain score from baseline to postintervention. The overall effect size-pooled MD in the Visual Analog Scale score-was 3.299 (95% CI: 2.045 to 4.552, P < 0.001). Heterogeneity (I2) was 36.11%. LIMITATIONS: Small sample size, lack of control group, and varying pain generators and interventional technique between studies contribute to the limitations of the analysis. CONCLUSIONS: Our findings suggest that therapeutic intraarticular cervical facet injections may be effective in the treatment of CGH. Because of the heterogeneity among the studies, these results should be interpreted with caution.

Normal Range of Movement During Rotation Stress Testing for the Alar Ligaments: An Observational Study.

OBJECTIVE: The purpose of this study was to determine the normal range of rotation occurring during rotation stress testing for alar ligament integrity and to ascertain whether rotation range on testing is affected by an individual's age. METHOD: In this observational study, 88 people aged 18 to 86 years old with no current neck problems or known risk factors for craniocervical instability underwent rotation stress testing for the alar ligaments. The test was performed in each direction in neutral, flexion, and extension, with the participant both sitting and supine. Rotation range was recorded using an electromagnetic movement tracking system. Range was assessed overall and then compared by 10-year age groups using analysis of variance. Reliability of measurements was assessed by intraclass correlation coefficient(2,1) and standard error of measurement. RESULTS: Mean angles of upper cervical rotation ranged between 10.91° (standard deviation 3.38°) to 16.12° (standard deviation 5.13°). Overall measured rotation ranged from 1.37° to 33.22°. Participants in older age groups generally displayed reduced rotation; however, the reduction was less than 4°. Reliability of rotation measurements was good to excellent, with the intraclass correlation coefficient ranging from 0.80 to 0.99. CONCLUSIONS: Normal range of rotation measured during stress testing for the alar ligament varied widely but did not exceed 33o. All values measured in this study fell below recommendations for ligament integrity. Age-related change was not clinically significant in the interpretation of this test in this asymptomatic population.

Percutaneous CT-Guided Biopsy of the Craniovertebral Junction: Safety, Diagnostic Yield, and Technical Notes.

The craniovertebral junction defined as the occiput, the atlas, and the axis is a complex bony region that contains vital neural and vascular structures. We report the experience of a single academic institution regarding CT-guided biopsy of this skeletal region. We reviewed all of the CT-guided biopsies performed in our department, completed in the craniovertebral junction. We collected data in regard to biopsy procedures, patients' vital statistics, and histopathological diagnosis. In total, 16 patients (8M and 8F; mean age 52; range 16-86 years old) were included in this series. In eight patients, the lesions were located in the atlas vertebra (8/16-50%), in six patients in the axis (37.5%), and in two patients in the occiput (12.5%). No complications were observed during or after the procedures. All of the procedures were technically successful. The biopsy was diagnostic in 13/16 patients (81.3%): four metastatic lesions (25%-three breast and one prostate cancers), four multiple myeloma bone lesions (25%), three aneurismal bone cysts (18.8%), one aggressive hemangioma (6.3%), and one pseudogout (6.3%). Moreover, in two-thirds (66.6%) of non-diagnostic histological reports, malignancies were excluded. CT-guided percutaneous biopsy is a safe tool and allows obtaining a histological diagnosis, in most cases, even in the most delicate site of the human skeleton-the craniovertebral junction.

An osteometric and 3D analysis of the atlanto-occipital joint: An initial screening method to exclude crania and atlases in commingled remains.

OBJECTIVES: The anatomical features of the atlanto-occipital joint can be potentially useful in re-associating or excluding crania to atlases in commingled remains. This study investigated whether linear measurements and the 3-dimensional (3D) surface of occipital condyles and articular facets of atlases can represent valid insights for this purpose. METHODS: The variations among eight corresponding linear distances were analyzed in a sample of 150 individuals through six supervised machine learning techniques attempting to develop classifiers able to identify elements belonging to the same individual. Furthermore, a 3D analysis was conducted on the articular surfaces through superimpositions of 3D models of corresponding and non-corresponding crania and atlases obtained by using respectively stereophotogrammetry and laser scanning. This analysis investigated differences in terms of point-to-point distances (Root Mean Square, RMS) of superimposed 3D surfaces. RESULTS: None of the six machine learning techniques were able to correctly detect a satisfying percentage of correspondent pairs in the overall sample by using the linear variables. The 3D analysis of the articular surfaces found RMS values over 0.53 mm only for superimposed non-corresponding surfaces, which sets a threshold value to identify 32% of incorrect pairs. DISCUSSION: The re-association of cranium to atlas proved to be challenging and hardly possible when considering only metric variables. However, the 3D geometry of the articular surfaces represents a valid variable for this purpose and 3D analyses pave the way for an initial exclusion of incorrect re-associations, thus should not be considered as a re-association method per se, but as an exclusionary screening technique.

Radiological approach to basilar invagination type B: Reliability and accuracy.

OBJECTIVES: This study aims to determine the reliability of the radiological tests used in the diagnosis of basilar invagination (BI). METHODS: Patients diagnosed with type B basilar invagination, who had both magnetic resonance (MR) and computed tomography (CT) imaging between January 2014 and November 2019 were included in this retrospective reliability study. In this study, distance from odontoid apex to Chamberlain's line (OA-CL) was accepted as a reference method for the diagnosis. Forty-two BI cases and 79 controls were included. Three radiologists with different levels of experience individually evaluated OA-CL, Boogard's angle (BoA), clivo-axial angle (CXA), clivo-dens angle (CDA), and clivo-palate angle (CPA) on midsagittal CT and MR images. Statistical analysis was made with the intraclass correlation coefficient (ICC), t-test, and receiver operating characteristic (ROC) curve. RESULTS: The ICC for CT and MR were; 0.977-0.973 (OA-CL), 0.912-0.882 (BoA), 0.845-0.846 (CXA), 0.862-0.864 (CDA), and 0.762-0.747 (CPA) respectively (P < 0.001). The areas under the ROC curve were 0.977 (BoA), 0.832 (CXA), 0.852 (CDA), and 0.719 (CPA) (P < 0.001). The cut-off measures were ≥137.84° (BoA), ≤149.25° (CXA), ≤129.58° (CDA), and ≤61.83° (CPA). The diagnostic accuracies were 0.954 (BoA), 0.664 (CXA), 0.704 (CDA), 0.438 (CPA) (P < 0.001). CONCLUSIONS: OA-CL and BoA express excellent inter-rater agreement than CXA, CDA, and CPA, which are limited due to morphological variations and head spatial position. BoA is the second most reliable diagnostic test. CXA, CDA, should only be used for complementary information. CPA was found inadequate for the diagnosis of BI..

Occipitocervical fixation: A case report of our techniques and results.

INTRODUCTION: Occipitocervical fixation (OCF) can provide good fusion rate to treat various craniovertebral junction (CVJ) pathologies. Biomechanically it gives rigid fixation, good fusion rate, and allows for effective decompression. However, rigid fixation on the mobile occipitocervical junction has shortcomings that affect the post-operative clinical functional outcomes and range of motion. This study aimed to evaluate and elaborate the functional outcomes, range of motions, and radiographic findings in our patients underwent OCF. CASE REPORT: We presented a report of 3 patients underwent posterior decompression procedure followed by occipitocervical fixation. All three patients' clinical outcome was assessed clinically by, Japanese Orthopaedic Association (JOA) score and grading, Karnofsky, range of motion and radiographic cervical alignment evaluation parameters. RESULT: All patients have seen improvement (minimal 1 grade in JOA and >30 points of Karnofsky score) in 3 months after the procedure, had a tolerable range of motion limitation, normal range of cervical lordotic and cervical brow vertebral angle (CBVA). Unfortunately, one patient with loss of cranial fixation may be related to history of infection and lack of post-operative wound care. CONCLUSSION: Our cases conclude that Occipitocervical fixation is a safe technique that provides excellent fusion rate with good functional outcome and tolerable range of motion limitation. Due to its unique anatomy and technically demanding, serial post-operative monitoring evaluation of this procedure is paramount.

Comparison of Jefferson-fracture reduction plate and micro titanium plate in the transoral single-segment fixation of unstable atlas fractures / 中华创伤骨科杂志

Objective:To compare Jefferson-fracture reduction plate (JeRP) and micro titanium plate in the transoral single-segment fixation of unstable atlas fractures.Methods:From January 2008 to December 2020, 45 patients with unstable atlas fracture were treated by single-segment fixation through an oral approach with a JeRP or a micro titanium plate at Department of Orthopedic Surgery, General Hospital of Southern Theatre Command. They were 24 males and 21 females, aged from 15 to 67 years. By the Gehweiler classification, 11 atlas fractures were type Ⅰ and 34 type Ⅲ; by the American Spinal Injury Association (ASIA) classification, the spinal cord injury was grade D in 7 cases and grade E in 38 cases; by the Dickman classification, the atlas transverse ligament injury was type Ⅰ in 4 cases and type Ⅱ in 11 cases. Of the patients, 26 were treated by transoral single-segment fixation with a JeRP and 19 by transoral single-segment fixation with a micro titanium plate. The 2 groups were compared in terms of baseline data, operation time, blood loss, hospital stay, visual analog scale (VAS) for neck pain and atlas lateral mass displacement (LMD) before operation and at the last follow-up, and intraoperative and postoperative complications.Results:The 2 groups were comparable because there was no significant difference between them in the preoperative general data ( P>0.05). All patients were followed up for 12 to 55 months (mean, 21.8 months). Wound dehiscence or infection was observed in none of the patients after operation. About 12 months after operation, all fractures achieved bony union, neck pain basically disappeared, and neck movement had no obvious limitation. The hospital stay was (13.9±2.2) d for the JeRP group and (14.2±2.9) d for the micro titanium plate group, showing no significant difference between the 2 groups ( P>0.05). The operation time was (203.5±173.4) min and the blood loss (167.3±138.6) mL in the JeRP group, significantly more than those in the micro titanium plate group [(121.5±50.5) min and (98.4±57.2) mL] ( P<0.05). In the JeRP group, the preoperative LMD was (6.7±1.7) mm and the preoperative VAS score (6.8±1.0) points, significantly higher than the last follow-up values [(0.7±0.6) mm and (0.7±0.6) points] ( P<0.05). In the micro titanium plate group, the preoperative LMD was (6.6±1.5) mm and the preoperative VAS score (6.7±0.9) points, significantly higher than the last follow-up values [(0.9±0.6) mm and (0.8±0.7) points] ( P<0.05). However, there was no significant difference in the preoperative or the last follow-up comparison between the 2 groups ( P>0.05). Implant loosening was observed in one patient in the JeRP group while foreign body sensation in the throat was reported in one patient after operation in the micro titanium plate group. Conclusions:Both JeRP and micro titanium plate in the transoral single-segment fixation can lead to effective treatment of unstable atlas fractures. Compared with JeRP, the micro titanium plate can effectively shorten operation time and reduce blood loss due to its smaller size and lower incision.

A clival-cervical plate fixation for the craniovertebral instability: a biomechanical study / 中华骨科杂志

Objective:To develop a specialized clival-cervical plate fixation (CCPF) for anterior surgery to treat craniovertebral instability, and to compare it with a posterior occipitocervical fixation (POCF) in biomechanical validation.Methods:Based on the measurement of 40 adult dry bones and 30 volunteers CT images, the clival-cervical plate was designed and manufactured. 8 cadaveric specimens (occiput-C 3) were tested in five conditions including the intact status, the intact+CCPF status, the injury status, the injury+CCPF status, and the injury+POCF status. Specimens were applied a pure moment of 1.5 N·m in flexion, extension, lateral bending, and axial rotation. Calculating and comparing the range of motion (ROM) and neutral zone (NZ) for the occiput to C 2. The effects of different fixation methods on the distribution of ROMs at the occipitocervical region were compared. Results:The injury+CCPF status constrained ROMs to 1.7° in flexion ( q=4.68, P=0.055) , 1.2° in extension ( q=0.39, P=0.9922) , 2.8° in lateral bending ( q=1.25, P=0.814) , and 4.3° in axial rotation ( q=5.08, P=0.035) , resulted in larger ROM in axial rotation but similar ROMs in other directions ( P>0.05) when compared with the injury+POCF status. There were no significant differences between the above two fixation methods in flexion-extension ( q=1.94, P=0.554) , lateral bending ( q=1.79, P=0.611) and axial rotation ( q=2.14, P=0.478) for the NZs. For the flexion, extension,lateral bendingand axial rotation direction, the proportion of the C 1, 2 ROM to the overall ROM was 28%, 25%, 34% and 56% respectively in the injury+CCPF status, and it was 59%, 53%, 42% and 71% respectively in the injury+POCF status. Conclusion:CCPF is a biomechanically effective alternative or supplemental method of POCF for the craniocervical instability.

Hipoplasia de cóndilo occipital: hallazgo en telerradiografía de perfil / Unilateral hypoplastic occipital condyle: anincidental finding on a cephalometric lateral radiograph

Introducción: Los cóndilos occipitales y procesos articulares superiores de atlas conforman la articulación atlanto-occipital, la que contribuye en la flexión y extensión de cabeza y cuello. La hipoplasia de cóndilo occipital (HCO) esuna anomalía del desarrollo poco frecuente, pudiendo presentarse aislada o como parte de un síndrome. Si bien el diagnóstico y manejo de una HCO corresponde al área médica, es posible que en ciertos casos esta anomalía pueda ser advertida por el odontólogo. Caso: Paciente sexo femenino, 23 años, asintomática, acude a realizarse una telerradiografía de perfil, previo a tratamiento de ortodoncia. En dicha radiografía se observóuna desproyecciónen sentido vertical del arco posterior de atlas. El informe radiográfico incluyó un diagnóstico presuntivo de HCO. Posteriormente se complementó con un examen de tomografía computarizada de haz cónico (TCHC), que confirmó el diagnóstico de HCO derecho. Conclusión: La HCO puede observarse en una telerradiografía de perfil, y su diagnóstico puede realizarlo un radiólogo maxilofacial. La confirmación del diagnóstico debe realizarse con imágenes de TCHC para analizar las estructuras óseas, y con resonancia magnética para analizar los tejidos blandos circundantes (AU)

Introduction: Occipital condyles and articular processes of atlas vertebrae form the atlanto-occipital joint. This joint contributes to flexion and extension of head and neck. Hypoplasia of the occipital condyle (HCO) is an unusual developmental anomaly, being shown isolated or as a part of a syndrome. While diagnosis and clinical management of HCO corresponds to the medical area, some cases of HCO may be adverted by a dentist. Case: Female patient, 23 years old, asymptomatic, come to be undergone to a lateral cephalometric radiograph prior to an orthodontic treatment. In this image the posterior arch of the atlas was observed as not superimposed. In the radiographic report the presumptive diagnosis included HCO. This radiographic examination was complemented with a cone-beam computed tomography examination (CBCT), which confirmed the diagnosis of HCO. Conclusion: HCO can be seen on a lateral cephalometric radiograph, and the diagnosis can be performed by a maxillofacial radiologist. Confirmation of diagnosis should be done with CBCT images to analyze bone structures, and with magnetic resonance imaging to analyze surrounding soft tissues. (AU)