Posterior cervical pedicle screw rod short-segment internal fixation for the treatment of atlantoaxial fracture and dislocation / 中国骨伤

OBJECTIVE@#To investigate the clinical efficacy of posterior cervical pedicle screw short-segment internal fixation for the treatment of atlantoaxial fracture and dislocation.@*METHODS@#The clinical data of 60 patients with atlantoaxial vertebral fracture and dislocation underwent surgery between January 2015 and January 2018 were retrospectively analyzed. The patients were divided into study group and control group according to different surgical methods. There were 30 patients in study group, including 13 males and 17 females, with an average age of (39.32±2.85) years old, were underwent short-segment internal fixation with posterior cervical pedicle screws. There were 30 patients in control group, including 12 males and 18 females, with an average age of (39.57±2.90) years old, were underwent posterior lamina clip internal fixation of the atlas. The operation time, intraoperative blood loss, postoperative ambulation time, hospitalization time and complications between two groups were recorded and compared. The pain visual analogue scale(VAS), Japanese Orthopedic Association(JOA) score of neurological function, and fusion status were evaluated between two groups.@*RESULTS@#All patients were followed up for at least 12 months. The study group was better than control group in operation time, intraoperative blood loss, postoperative off-bed activity time, and hospital stay (P=0.000). One case of respiratory tract injury occurred in study group. In control group, 2 cases occurred incision infection, 3 cases occurred respiratory tract injury, and 3 cases occurred adjacent segmental joint degeneration. The incidence of complications in study group was lower than that in control group (χ2=4.705, P=0.030). At 1, 3, 7 days after operation, VAS of study group was lower than that of control group(P=0.000). At 1, 3 months after operation, JOA score of study group was higher than that of control group(P=0.000). At 12 months after operation, all the patients in the study group achieved bony fusion. In control group, there were 3 cases of poor bony fusion and 3 cases of internal fixation fracture, the incidence rate was 20.00%(6/30). The difference between two groups was statistically significant (χ2=4.629, P=0.031).@*CONCLUSION@#Posterior cervical short-segment pedicle screw fixation for atlantoaxial fracture and dislocation has the advantages of less trauma, shorter operation time, fewer complications, and less pain, and can promote the recovery of nerve function as soon as possible.

Biomechanical evaluation of four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs

ABSTRACT Purpose: This study compared, through biomechanical evaluation under ventral flexion load, four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs. Methods: In total, 28 identical atlantoaxial joint models were created by digital printing from computed tomography images of a dog, and the specimens were divided into four groups of seven. In each group, a different technique for ventral stabilization of the atlantoaxial joint was performed: transarticular lag screws, polyaxial screws, multiple screws and bone cement (polymethylmethacrylate-PMMA), and atlantoaxial plate. After the stabilization technique, biomechanical evaluation was performed under ventral flexion load, both with a predefined constant load and with a gradually increasing load until stabilization failure. Results: All specimens, regardless of stabilization technique, were able to support the predefined load without failing. However, the PMMA method provided significant more rigidity (p ≤ 0.05) and also best resisted the gradual increase in load, supporting a significantly higher maximum force (p ≤ 0.05). There was no statistical difference in flexural strength between the transarticular lag screws and plate groups. The polyaxial screws method was significantly less resistant to loading (p ≤ 0.05) than the other groups. Conclusions: The PMMA technique had biomechanical advantages in ventral atlantoaxial stabilization over the other evaluated methods.

Diagnosis and treatment of atlantoaxial dislocation / 中华骨科杂志

Atlantoaxial dislocation is a pathological anatomical condition caused by the loss of stability between the atlantoaxial joints, which is a serious disabling disease in spine surgery, and may even endanger the patient's life. The causes of atlantoaxial dislocation include traumatic, congenital, inflammatory, degenerative, tumor, and other factors. Since the symptoms and signs are not specific in clinic, imaging examination is particularly important. Atlantoaxial dislocation is mainly classified according to the etiology, the relative position of atlas and axis, and the difficulty of reduction. Accurate classification is of great significance for the selection of treatment options. There is no popular guideline for surgical indications of atlantoaxial dislocation. Patients presenting with related symptoms or spinal cord dysfunction are generally recognized surgical indications in clinical practice. With the continuous improvement and optimization of atlantoaxial screw placement, reduction and fusion technology, supplemented by new equipment in spine surgery, the surgery-related risks and complications have been greatly reduced, and the surgical treatment of atlantoaxial dislocation can obtain good reduction and fusion results. This tutorial summariz the etiology, diagnosis, classification, treatment, complications, and prognosis of atlantoaxial dislocation, in order to provide a more complete and refined reference for clinical diagnosis and treatment.

Anterior cervical release and posterior fixation for the treatment of irreducible atlantoaxial dislocation with retropharyngeal internal carotid artery / 中华骨科杂志

Objective:To investigate the clinical effect of anterior cervical release and posterior fixation in the treatment of irreducible atlantoaxial dislocation with retropharyngeal internal carotid artery.Methods:Thirteen patients with irreducible atlantoaxial dislocation of retropharyngeal internal carotid artery from January 2015 to July 2019 were treated with anterior cervical release and posterior fixation. There were 8 males and 5 females, aged from 34 to 65 years with an average of 46.1±12.6 years. Positive, lateral and dynamic X-ray films, MR and CTA were performed before operation. There were 4 cases with bilateral retropharyngeal internal carotid artery and 9 cases with unilateral retropharyngeal internal pharyngeal artery. The time of operation, the amount of bleeding and intraoperative and postoperative complications were recorded. The main observations were Japanese Orthopaedic Association (JOA) score, atlantodental interval (ADI), Chamberlain line (CL), and changes in the morphology of the retropharyngeal internal carotid artery and implant fusion.Results:All the operations completed successfully. The operation time was 210-260 min, the average was 245±21 min; the blood loss was 350-600 ml, the average blood loss was 490±107 ml. There was no injury of internal carotid artery, vertebral artery, spinal cord or nerve root during the operation. All patients were followed up for 9 to 24 months, with an average of 15.1±6.2 months. Preoperative JOA score was 6.9±2.3 points, 1 month after operation was 13.5±2.5 points, and the last follow-up was 14.3±2.1 points. The difference was statistically significant ( F=30.91, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and the improvement rate of JOA score was 75.6%±15.2%. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). The preoperative ADI was 8.9±2.2 mm, 1 month after operation was 1.1±0.8 mm, and the last follow-up was 1.2±0.9 mm. The difference was statistically significant ( F=114.69, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and ADI had returned to normal level. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). The preoperative CL was 11.7±4.8 mm, 1 month after operation was 1.6±2.1 mm, and the last follow-up was 1.8±2.3 mm. The difference was statistically significant ( F=34.19, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and the position of odontoid process returned to normal level. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). Bone graft fusion was received at 6 to 12 months after operation, with an average of 10.2 months. Conclusion:CTA examination should be performed before anterior release of atlantoaxial dislocation to understand the position and shape of internal carotid artery. Anterior cervical release combined with posterior bone graft fusion is an effective method for the treatment of irreducible atlantoaxial dislocation with retropharyngeal internal carotid artery without increasing the risk of internal carotid artery injury.

The clinical characteristics and treatment of "sandwich" atlantoaxial dislocation / 中华骨科杂志

Objective:To evaluate the specialty of the clinical features, treatment procedure, clinical outcome, and prognosis in the patients with "sandwich" atlantoaxial dislocation (AAD).Methods:From 2008 to 2018, 160 cases with "sandwich" AAD were retrospectively selected from the case series of AAD in Peking University Third Hospital. The case series had 80 males and 80 females. The mean age at the initial visit was 35.5±14.6 years (range, 5-77). The clinical courses, treatment methodology and prognosis were reviewed. And the surgical approach, posterior fixation segment and the recovery of neurological function were mainly summarized. The atlantodental interval (ADI), the distance by which the odontoid exceeded the Chamberlain line and the cervical-medullary angle were analyzed.Results:The most common symptoms included weakness or numbness of the limbs (67.5%, 108/160), unstable gait (30%, 48/160) and vertigo (20%, 32/160). Among all, 130 cases (81.3%, 130/160) had myelopathy, with the Japanese Orthopaedic Association (JOA) scores from 4 to 16 (mean JOA scores 13.5±2.5). Cranial neuropathy was involved in 20 cases (12.5%). Radiological findings showed brainstem and/or cervical-medullar in 130 cases (81.3%), syringomyelia in 37 cases (23.1%) and Chiari malformation in 30 cases (18.8%). Computed tomography angiography (CTA) was performed in 90 cases, which showed vertebral artery anomalies in 55 cases (61.0%) and excessive medialized internal carotid artery in 5 cases (5.6%). All cases had no spinal cord or vertebral artery injury. The surgery included posterior occipito-cervical fusion (reducible dislocation, 145 cases), and transoral release followed by posterior fusion (irreducible dislocation, 15 cases). Fifty-seven cases were treated using alternative fixation technique. The average follow-up time was 50.5±22.4 months (range, 24 to 120 months). All of 152 cases (95.0%) achieved solid atlantoaxial fusion; there was no obvious osseous fusion formation on postoperative images in 6 cases (3.8%), but no atlantoaxial instability was found on dynamic radiographs; screw loosening happened in 2 patients (1.2%). Nine patients (5.6%) suffered complications, including 4 cases with recurrent dislocation, 2 screw loosening, 2 cases with bulbar paralysis and 1 wound infection. The mean postoperative JOA was 15.1±1.8 (range, 5-17), and the mean neurological improvement rate was 42.9%±33.3% in the patients with myelopathy.Conclusion:"Sandwich" AAD, a subgroup of AAD, has unique clinical features: earlier onset age and more severe myelopathy. The incidence of bone and vascular malformation is higher. So alternative surgical plan and hybrid fixation should be prepared for this subgroup of AAD.

Subclassification and clinical treatment options of refractory atlantoaxial dislocation / 中华骨科杂志

Objective:To subdivide clinical classification of refractory atlantoaxial dislocation, and evaluate the reliability of new subdivide clinical classification of refractory atlantoaxial dislocation.Methods:From January 2010 to December 2018, 48 patients with refractory atlantoaxial dislocation were treated, including 19 males and 29 females, aged 16 to 65 years, with an average of 39.2±13.3 years. According to the changes of relative anatomical position of C 1 and C 2 under general anesthesia with heavy traction of 1/6 body weight, subdivide clinical classification of refractory atlantoaxial dislocation were proposed, and refractory atlantoaxial dislocation was divided into traction loosening type (atlantoaxial angle≥5°) and traction stabilization type (atlantoaxial angle<5°). The traction loosening type was directly reduced by posterior atlantoaxial screw-rod fixation and fusion without anterior or posterior soft tissue release. For traction stabilization type, transoral soft tissue release was performed first, and then transoral anterior reduction plate fixation and fusion or posterior atlantoaxial screw-rod fixation and fusion were performed. Atlantodental interval (ADI) and atlantoaxial angle (AAA) were measured and collected before and after surgery to evaluate atlantoaxial reduction. The space available for the spinal cord (SAC) were measured to evaluate spinal cord compression. Visual analogue score (VAS) was used to evaluate the neck pain levels, and Japanese Orthopaedic Association (JOA) scores was used to evaluate the neurological function. American Spinal Cord Injury Association impairment scale (AIS) was used to evaluate the degree of spinal cord injury. One week, 3, 6, 12 months postoperatively and the annual review of the X-ray and CT scan were checked, in order to evaluate the reduction, internal fixation and bone graft fusion. Results:Among all 48 cases, 22 cases were traction loosening type, of which posterior atlantoaxial screw-rod fixation and fusion were performed in 16 cases and occipitocervical fixation and fusion in 6 cases. 26 cases were traction stabilization type, and they all underwent anterior transoral release, and then, anterior TARP fixation and fusion were performed in 24 cases and posterior screw-rod fixation and fusion in the other 2 cases. X-ray, CT and MRI images and of all patients 1 week after surgery showed good atlantoaxial reduction and decompression of spinal cord. In each of the two types, there was one case lost to follow-up. For 46 cases in follow-up, the follow-up time ranged from 6 to 72 months, with an average of 38.0±17.2 months. Among 46 cases, 21 cases of traction loosening type showed that, ADI reduced from preoperative 9.9±2.2 mm to 2.3±0.9 mm at 3 months after surgery and 2.3±1.0 mm at the last follow-up, AAA increased from preoperative 57.9°±12.3° to 91.0°±2.2° at 3 months after surgery and 90.9°±2.2° at the last follow-up, SAC increased from preoperative 9.8±1.3 mm to 15.1±0.7 mm at 3 months after surgery and 14.9±0.7 mm at the last follow-up, VAS score reduced from preoperative 1.5±2.1 to 0.7±1.0 at 3 months after surgery and 0.3±0.6 at the last follow-up, and JOA score increased from preoperative 10.2±1.7 to 13.3±1.3 at 3 months after surgery and 14.9±1.5 at the last follow-up. Twenty-five cases of traction stabilization type presented that, ADI reduced from preoperative 9.7±2.0 mm to 2.1±1.4 mm at 3 months after surgery and 2.1±1.3 mm at the last follow-up, AAA increased from preoperative 55.8°±9.2° to 90.9°±1.4° at 3 months after surgery and 90.9°±1.3° at the last follow-up, SAC increased from preoperative 10.5±1.0 mm to 15.4±0.5 mm at 3 months after surgery and 14.8±2.8 mm at the last follow-up, VAS score reduced from preoperative 1.7±2.1 to 0.7±0.9 at 3 months after surgery and 0.3±0.5 at the last follow-up, and JOA score increased from preoperative 10.1±1.3 to 12.9±1.5 at 3 months after surgery and 14.4±1.3 at the last follow-up. In the traction loosening type, all the 10 grade D patients were improved to grade E at the last follow-up. In the 2 grade C patients of traction stabilization type before surgery, 1 patient was improved to grade E, 1 patient was improved to grade D, and all 11 patients with grade D were improved to grade E at the last follow-up. Bony fusion was obtained in all patients from 3 to 6 months, with an average of 4.4±1.5 months. During follow-up period, no looseness of internal fixation or redislocation happened.Conclusion:Refractory atlantoaxial dislocation can be divided into traction loosening type and traction stabilization type. For traction loosening type, satisfactory reduction can be achieved by using posterior atlantoaxial screw-rod system without soft tissue release. For traction stabilization type, anterior release is preferable, and then anterior TARP or posterior screw-rod can be used to achieve satisfactory reduction.

Evidence-based guideline for clinical diagnosis and treatment of acute combination fractures of the atlas and axis in adults (version 2023) / 中华创伤杂志

The acute combination fractures of the atlas and axis in adults have a higher rate of neurological injury and early death compared with atlas or axial fractures alone. Currently, the diagnosis and treatment choices of acute combination fractures of the atlas and axis in adults are controversial because of the lack of standards for implementation. Non-operative treatments have a high incidence of bone nonunion and complications, while surgeries may easily lead to the injury of the vertebral artery, spinal cord and nerve root. At present, there are no evidence-based Chinese guidelines for the diagnosis and treatment of acute combination fractures of the atlas and axis in adults. To provide orthopedic surgeons with the most up-to-date and effective information in treating acute combination fractures of the atlas and axis in adults, the Spinal Trauma Group of Orthopedic Branch of Chinese Medical Doctor Association organized experts in the field of spinal trauma to develop the Evidence-based guideline for clinical diagnosis and treatment of acute combination fractures of the atlas and axis in adults ( version 2023) by referring to the "Management of acute combination fractures of the atlas and axis in adults" published by American Association of Neurological Surgeons (AANS)/Congress of Neurological Surgeons (CNS) in 2013 and the relevant Chinese and English literatures. Ten recommendations were made concerning the radiological diagnosis, stability judgment, treatment rules, treatment options and complications based on medical evidence, aiming to provide a reference for the diagnosis and treatment of acute combination fractures of the atlas and axis in adults.

Imaging anatomical study and clinical application of transoral axis slide and rotation osteotomy technique / 中华骨科杂志

Objective:To introduce a novel technique note about anterior decompression through transoral axis slide and rotation osteotomy (ASRO) and identify its imaging parameters related to osteotomy, and to explore its clinical application value.Methods:CT data of cervical spine of 90 subjects were collected, including 54 males and 36 females. The age ranged from 26 to 72 years, with an average age of 48.7 years. The Mimics software was used to reconstruct the atlantoaxial three-dimensional model. We plan to perform osteotomy on both sides of the axis of the vertebral body in the anteroposterior direction and the ASRO related anatomical parameters were measured, including the minimum osteotomy angle, the maximum osteotomy angle, the minimum and maximumdistance between the osteotomy trajectory and the inner side of the articular surface, the length of the upper articular surface of the axis side mass, the depth of osteotomy at the highest point and lowest point of the axial osteotomy surface and the minimum osteotomy depth. A 56-year-old female patient was admitted to the hospital due to atlantoaxial dislocation with failure of occipital-cervical fusion, difficulty walking, weakness and hypoaesthesia in four limbs. Imaging revealed that narrow space between the transversal walking wire and upper-posterior of the odontoid process, compressing the spinal cord from the front and the back respectively. The ASRO technique was performed on the patient under neuro-electrophysiological monitoring, and the osteotomy angle, osteotomy depth, narrowest width of the upper cervical spinal canal, the medullary, spinal cord angle were measured and Japanese Orthopaedic Association Scores (JOA) cervical myelopathy evaluation were performed after the operation to evaluate the surgical treatment effect.Results:The minimum osteotomy angle and the maximum osteotomy angle was 14.7°± 4.36° and 33.0°± 8.67°. The minimum and maximumdistance between the osteotomy trajectory and the inner side of the articular surface, and the length of the upper articular surface of the axis side mass was 6.0±1.80 mm, 12.2±3.17 mm, and 17.2±1.90 mm, the ratio of the former two to the latter was 34%±8.7% and 70%± 15.0%. The depth of osteotomy at the upper edge, lower edge and narrowest place of the axial osteotomy surface were 6.0±1.80 mm, 12.2±3.17 mm and 17.2±1.90 mm. The postoperative imaging of the patient showed that the osteotomy angle was 17.1° on left side and 16.5° on right side, and the depth of osteotomy at the upper edge, lower edge and narrowest place of the axial osteotomy surface were 17.1 mm, 13.2 mm, and 9.1 mm on left side, and 17.4 mm, 11.8 mm, 8.46 mm on right side. All measured values met the ranges which were shown in the imaging anatomical study. The narrowest width of the upper cervical spinal canal increased from 6.58 mm to 15.28 mm, the medullary spinal cord angle increased from 131.7° to 153.8°postoperatively, and the cervical spine JOA score recovered from 6 points to 14 points, suggesting that the postoperative spinal canal space is obvious increased, the compression on the front of the spinal cord was significantly reduced. The patient's symptoms improved significantly.Conclusion:ASRO technique is a good choice for salvage of failed posterior occipitocervical fusion and some irreducible atlantoaxial dislocation because of the anterior bony fusion. It could direct decompress the spinal cord anteriorly, avoid the odontoid resection, which is a safe and feasible new technique.

Research progress of causes and strategies in revision surgery for atlantoaxial dislocation / 中国骨伤

Atlantoaxial dislocation (AAD) is a kind of life-threatening atlantoaxial structural instability and a series of neurological dysfunction caused by common multidisciplinary diseases. The operation risk is extremely high because it is adjacent to the medulla oblongata and the location is deep. With the increase of the number of operations in the upper cervical region, postoperative complications such as failure of internal fixation, non fusion of bone graft and poor prognosis gradually increase.Incomplete primary operation, non fusion of bone graft, infection and congenital malformation are the potential causes. In addition, considering the objective factors such as previous graft, scar formation and anatomical marks changes, revision surgery is further difficult. However, there is currently no standard or single effective revision surgery method. Simple anterior surgery is an ideal choice in theory, but it has high risk and high empirical requirements for the operator;simple posterior surgery has some defects, such as insufficient reduction and decompression;anterior decompression combined with posterior fixation fusion is a more reasonable surgical procedure, but many problems such as posterior structural integrity and multilevel fusion need to be considered.This article reviews the causes and strategies of AAD revision surgery.

Traumatic atlantoaxial rotatory dislocation in the pediatric population / Luxação rotacional traumática de c1-c2 na população pediátrica / Luxación rotatoria traumática de c1-c2 en población pediátrica

ABSTRACT Objective: The treatment of C1-C2 rotatory dislocation remains controversial and surgery is rare. Surgical treatment is indicated when the injury satisfies the instability criteria or when it cannot be reduced. The objective of this study is to analyze the principles and the adaptations necessary for treating these injuries in the pediatric population. Methods: A retrospective case series study. Three cases of patients diagnosed with traumatic C1-C2 rotatory dislocation and treated surgically in our hospital were studied. Through critical analysis of the available literature, a practical guide was proposed to establish the principles and competencies for the treatment of these injuries. Results: The operated cases were female patients between 8 and 16 years of age, with a diagnosis of traumatic atlantoaxial dislocation. Two patients required preoperative skeletal traction with halo. All patients underwent posterior instrumented arthrodesis, two with a transarticular screw technique and one with mass and C2 isthmic (Göel-Harms) screws. Conclusion:. It is essential to determine if the injury is stable and reducible. We recommend treating this type of injury keeping the criteria and competencies related to the stability, alignment, biology and function of the spine in mind. Level of evidence IV; Case series.

RESUMO Objetivo: O tratamento da luxação rotacional de C1-C2 permanece controverso, e a cirurgia é rara. O tratamento cirúrgico é indicado quando a lesão satisfaz os critérios de instabilidade ou quando não pode ser reduzida. O objetivo deste estudo é analisar os princípios e a adequação necessários para tratar essas lesões na população pediátrica. Métodos: Estudo retrospectivo de série de casos. Foram estudados três casos em pacientes tratados cirurgicamente em nosso hospital com diagnóstico de luxação rotacional traumática de C1-C2. Por meio de análise crítica da literatura disponível, foi proposto um guia prático para estabelecer os princípios e a adequação do tratamento dessas lesões. Resultados: Os casos submetidos à cirurgia foram pacientes do sexo feminino, entre 8 e 16 anos de idade, com diagnóstico de luxação atlantoaxial traumática. Duas pacientes precisaram de tração esquelética pré-operatória com halo. Todas as pacientes foram submetidas à artrodese instrumentada por via posterior, duas com técnica de parafuso transarticular e uma com parafusos de massa e pedículo e lâmina em C2 (técnica de Göel-Harms). Conclusões: É essencial determinar se a lesão é estável e se pode ser reduzida. Recomenda-se tratar esse tipo de lesão tendo em mente os critérios e a adequação relacionados com estabilidade, alinhamento, biologia e função da coluna vertebral. Nível de evidência IV; Série de casos.

RESUMEN Objetivo: El tratamiento de la luxación rotatoria de C1-C2 permanece controversial y la cirugía es rara. Se indica tratamiento quirúrgico cuándo la lesión cumple criterios de inestabilidad o cuándo es considerada irreductible. El objetivo de este estudio es revisar los principios y competencias necesarios para tratar esas lesiones en la población pediátrica. Métodos: Estudio retrospectivo de serie de casos. Se estudian tres casos en pacientes tratados quirúrgicamente en nuestro hospital con diagnóstico de luxación rotatoria de C1-C2 traumática. A través del análisis crítico de la literatura disponible se elabora un esquema práctico para establecer los principios y competencias para el abordaje de estas lesiones. Resultados: Los casos intervenidos fueron pacientes de sexo femenino entre 8 y 16 años, con diagnóstico de luxación atlantoaxoidea traumática. Dos pacientes requirieron tracción esquelética preoperatoria con halo. A todas las pacientes se les practicó artrodesis instrumentada por vía posterior, dos con técnica de tornillos transarticulares y una con tornillos de masa e ístmicos de C2 (Göel-Harms). Conclusiones: Resulta imprescindible determinar si la lesión es estable y reductible. Siempre abordar este tipo de lesiones teniendo presentes los criterios y competencias relacionados con la estabilidad, alineación, biología y función de la columna vertebral. Nivel de Evidencia IV; Serie de casos.

Minimally invasive treatment of cervical1-2 epidural neurilemmoma / 北京大学学报(医学版)

OBJECTIVE@#To explore the minimally invasive surgical method for cervical1-2 epidural neurilemmoma.@*METHODS@#The clinical features, imaging characteristics and surgical methods of 63 cases of cervical1-2 epidural neurilemmoma from July 2010 to December 2018 were reviewed and analyzed. Pain and numbness in occipitocervical region were the common clinical symptoms. There were 58 cases with pain, 30 cases with numbness, 3 cases with limb weakness and 2 cases with asymptomatic mass. Magnetic resonance imaging (MRI) showed that the tumors located in the cervical1-2 epidural space with diameter of 1-3 cm. The equal or slightly lower T1 and equal or slightly higher T2 signals were found on MRI. The tumors had obvious enhancement. Individualized laminotomy was performed according to the location and size of the tumors, and axis spinous processes were preserved as far as possible. Resection of tumor was performed strictly within the capsule.@*RESULTS@#Total and subtotal resection of tumor were achieved in 60 and 3 cases respectively, and no vertebral artery injury was found. The operation time ranged from 60 to 180 minutes, with an average of 92.83 minutes. The hospitalization time ranged from 3 to 9 days, with an average of 5.97 days. All tumors were confirmed as neurilemmoma by pathology. There was no postoperative infection or cerebrospinal fluid leakage. There was no new-onset dysfunction except 9 cases of numbness in the nerve innervation area. The period of follow-up ranged from 6 months to 8 years (median: 3 years). All the new-onset dysfunction recovered completely. Pain disappeared in all of the 58 patients with pain. Numbness recovered completely in 27 patients while slight numbness remained in another 3 patients. Three patients with muscle weakness recovered completely. The spinal function of all the patients restored to McCormick grade Ⅰ. No recurrence was found on MRI. No cervical spine instability or deformity was found on X-rays.@*CONCLUSION@#It is feasible to resect cervical1-2 epidural neurilemmoma by full use of the anatomical space between atlas and axis and individual laminotomy. It is helpful to prevent cervical instability or deformity by minimizing the destruction of cervical2 bone and preserving normal muscle attachment to cervical2 spinous process. Strict intracapsular resection can effectively prevent vertebral artery injury.

Anatomical evaluation of the pedicle of the axis through computerized tomography in adults / Avaliação anatômica do pedículo do áxis através de tomografia computadorizada em adultos / Evaluación anatómica del pedículo del axis a través de la tomografía computarizada en adultos

ABSTRACT Objectives: The topography of the high cervical spine involves several traumatic, degenerative, and rheumatologic pathologies. With the evolution of surgical techniques and synthesis materials available for use in such region, an optimization of the anatomical understanding of this area is required. Methods: Therefore, this study evaluated 62 computed tomographies of the high cervical spine in an adult population, aiming at the study of the anatomical parameters of the axis pedicle. The measures analyzed in this observational study were pedicle length at axial section, pedicle length at sagittal section, pedicle thickness at axial section and interpedicular angulation. Results: Computed tomography is a necessary exam for the programming of C2 pedicle screws and is useful for determining the anatomical changes and evaluating the length of the screws that will be used. Furthermore, no statistically significant difference was observed in the length, angulation, and diameter of the pedicles of the axis in relation to sex or age. Conclusion: Regarding sex and age, no statistically significant difference on length, angulation, and pedicle diameter occur. There is an urgent need for computed tomography for surgical planning. Level of Evidence II; Transversal Diagnostic Studies - Investigation of a Diagnosis Test.

RESUMO Objetivos: A topografia da coluna cervical alta envolve diversas patologias de cunho traumático, degenerativo e reumatológico. Com a evolução de técnicas cirúrgicas e de materiais de síntese disponíveis para uso em tal região, é necessária uma otimização do entendimento anatômico desta área. Métodos: Assim, este estudo avaliou 62 tomografias computadorizadas da coluna cervical alta na população adulta, visando o estudo dos parâmetros anatômicos do pedículo do Áxis. Comprimento do pedículo no corte axial, comprimento do pedículo no corte sagital, espessura do pedículo no corte axial e angulação interpedicular foram as medidas analisadas neste estudo observacional. Resultados: A tomografia computadorizada mostra-se como um exame necessário para a programação da passagem de parafusos pediculares de C2, sendo útil para determinar as alterações anatômicas e avaliar o comprimento dos parafusos que irão ser utilizados. Também, não foram observadas diferenças estatisticamente significantes no comprimento, angulação e diâmetro dos pedículos do áxis em relação ao sexo. Conclusão: Não foram observadas diferenças estatisticamente significantes no comprimento, na angulação e no diâmetro dos pedículos. Urge a necessidade da Tomografia Computadorizada para o planejamento cirúrgico. Nível de Evidência II; Estudos Transversais de diagnósticos - Investigação de um exame para diagnóstico.

RESUMEN Objetivos: La topografía de la columna cervical alta involucra diversas patologías de origen traumático, degenerativo y reumatológico. Con la evolución de técnicas quirúrgicas y de materiales de síntesis disponibles para uso en tal región, es necesaria una optimización del entendimiento anatómico de esta área. Métodos: Así, este estudio evaluó 62 tomografías computarizadas de columna cervical alta en una población adulta, visando el estudio de los parámetros anatómicos del pedículo de axis. Las medidas analizadas en este estudio observacional fueron la longitud del pedículo en corte axial, la longitud del pedículo en corte sagital, el espesor del pedículo en corte axial y la angulación interpedicular. Resultados: La tomografía computarizada se muestra como un examen necesario para la programación del paso de tornillos pediculares de C2, siendo útil para determinar los cambios anatómicos y evaluar la longitud de los tornillos que se van a utilizar. Además, no se observó diferencias estadísticamente significativas en la longitud, angulación y diámetro de los pedículos del áxis en relación al sexo. Conclusión: En relación al sexo y edad no ocurren diferencias estadísticamente significativas en la longitud, la angulación y el diámetro de los pedículos. Urge la necesidad de la tomografía computarizada para la planificación quirúrgica. Nivel de Evidencia II; Estudios transversales de diagnóstico - Investigación de un examen para diagnóstico.

Dimorfismo sexual da vértebra áxis em uma coleção osteológica brasileira / Sex dimorphism by the axis vertebra in a Brazilian osteological collection

O objetivo desse estudo foi verificar o dimorfismo sexual por meio de medidas lineares (Comprimento do corpo e processo odontóide, Comprimento do processo odontóide, Comprimento do forame vertebral, Largura do forame vertebral, Distância dos processos transversos, Distância do processo transverso esquerdo ao processo espinhoso, Distância do processo transverso direito ao processo espinhoso) da segunda vertebra cervical denominada de áxis. Para tanto foram analisadas 181 áxis, sendo 103 masculinas e 78 femininas, na faixa de idade de 22 a 85 anos, pertencentes ao "Biobanco Tomográfico e Osteológico Prof. Eduardo Daruge da FOP/UNICAMP". Tais medidas foram feitas pelo paquímetro digital marca Stainless ­ hardned ® 150 mm Mauá ­ São Paulo, Brasil, após a calibração inter e intraoperador realizada por meio do teste de correlação intraclasse, teve como resultado o valor de 0,98 considerado excelente. Verificou-se que todas as medidas estudadas são dimórficas e foi possível estabelecer um novo modelo de regressão logística, a partir dos dados obtidos junto às ossadas. Concluiu-se que o modelo de regressão logística gerado ­ Germano Sexo = [- 22.7 + (0.16 × Comprimento do corpo) + (0.31 × Comprimento do forame vertebral) + (0.28 × Distância dos processos transversos)] ­ possui 72,4 % de acerto.

The objective of this study was to verify the sexual dimorphism through linear measurements (length of the body and dentinoid process, length of the dentinoid process, length of the vertebral foramen, width of the vertebral foramen, distance of the transverse processes, distance from the left transverse process to the spinal process , Distance from the right transverse process to the spinous process) of the second cervical vertebra known as the Áxis. For this purpose, 181 Axioms were analyzed, of which 103 were male and 78 were female, in the age range of 22 to 85 years, belonging to the "Tomographic and Osteological Biobank Prof. Eduardo Daruge of FOP / UNICAMP ". These measurements were made by the stainless - hardned ® digital pachymetro 150 mm Mauá - São Paulo, Brazil, after the inter and intra - operator calibration performed through the intraclass correlation test, resulting in a value of 0.98 considered excellent. It was verified that all the measures studied are dimorphic and it was possible to establish a new model of logistic regression, based on the data obtained from the bones. It was concluded that the logistic regression model generated Germano Gender = [- 22.7 + (0.16 × Body length) + (0.31 × Vertebral foramen length) + (0.28 × Distance of transverse processes), with 72.4% of hit.

Axis screws: results and complications of a large case series

SUMMARY OBJECTIVE: To present the surgical results of patients who underwent axis screw instrumentation, discussing surgical nuances and complications of the techniques used. METHODS: Retrospective case-series evaluation of patients who underwent spinal surgery with axis instrumentation using screws. RESULTS: Sixty-five patients were included in this study. The most common cause of mechanical instability was spinal cord trauma involving the axis (36 patients - 55.4%), followed by congenital craniocervical malformation (12 patients - 18.5%). Thirty-seven (57%) patients required concomitant C1 fusion. Bilateral axis fixation was performed in almost all cases. Twenty-three patients (35.4%) underwent bilateral laminar screws fixation; pars screws were used in twenty-two patients (33.8%), and pedicular screws were used isolated in only three patients (4.6%). In fourteen patients (21.5%), we performed a hybrid construction. There was no neurological worsening nor vertebral artery injury in this series. CONCLUSION: Axis screw instrumentation proved to be a safe and efficient method for cervical stabilization. Laminar and pars screws were the most commonly used

RESUMO OBJETIVO: Apresentar os resultados cirúrgicos de pacientes submetidos à instrumentação com parafusos do áxis, discutindo nuances cirúrgicas e complicações das técnicas utilizadas. MÉTODOS: Série retrospectiva de pacientes submetidos à instrumentação do áxis utilizando parafusos. RESULTADOS: Sessenta e cinco pacientes foram incluídos neste estudo. A causa mais comum de instabilidade foi trauma raquimedular envolvendo o áxis (36 pacientes - 55,4%), seguida por malformação craniocervical congênita (12 pacientes - 18,5%). Trinta e sete (57%) pacientes necessitaram concomitante fusão de C1. Fixação bilateral foi realizada em quase todos os casos. Vinte e três pacientes (35,4%) foram submetidos à fixação com parafusos de lâmina; parafusos de pars foram utilizados em 22 pacientes (33,8%) e de pedículo, isoladamente, em três (4,6%). Em 14 casos (21,5%), realizamos técnicas combinadas. Não houve piora neurológica ou lesão de artéria vertebral nesta série de casos. CONCLUSÃO: A instrumentação com parafusos do áxis foi um método seguro e eficaz para estabilização cervical. A fixação da lâmina e a da pars foram as técnicas mais utilizadas.

The C2 Pedicle Width, Pars Length, and Laminar Thickness in Concurrent Ipsilateral Ponticulus Posticus and High-Riding Vertebral Artery: A Radiological Computed Tomography Scan-Based Study

STUDY DESIGN: Retrospective radiological study. PURPOSE: We aimed to determine the prevalence of ponticulus posticus (PP) and high-riding vertebral artery (HRVA) occurring simultaneously on the same side (PP+HRVA) and in cases of PP+HRVA, to assess C2 radio-anatomical measurements for C2 pars length, pedicle width, and laminar thickness. OVERVIEW OF LITERATURE: PP and HRVA predispose individuals to vertebral artery injuries during atlantoaxial fixation. In cases of PP+HRVA, the construct options thus become limited. METHODS: Consecutive computed tomography scans (n=210) were reviewed for PP and HRVA (defined as an internal height of <2 mm and an isthmus height of <5 mm). In scans with PP+HRVA, we measured the ipsilateral pedicle width, pars length, and laminar thickness and compared them with controls (those without PP or HRVA). RESULTS: PP was present in 14.76% and HRVA in 20% of scans. Of the 420 sides in 210 scans, PP+HRVA was present on 13 sides (seven right and six left). In scans with PP+HRVA, the C2 pars length was shorter compared with controls (13.69 mm in PP+HRVA vs. 20.65 mm in controls, p<0.001). The mean C2 pedicle width was 2.53 mm in scans with PP+HRVA vs. 5.83 mm in controls (p<0.001). The mean laminar thickness was 4.92 and 5.48 mm in scans with PP+HRVA and controls, respectively (p=0.209). CONCLUSIONS: The prevalence of PP+HRVA was approximately 3% in the present study. Our data suggest that, in such situations, C2 pedicle width and pars length create important safety limitations for a proposed screw, whereas the translaminar thickness appears safe for a proposed screw.

Tomographic analysis of subaxial cervical vertebrae in children between 0 and 12 years / Análise tomográfica das vértebras cervicais subaxiais em crianças de 0 a 12 anos / Análisis tomográfica de vertebras cervicales subaxiales en niños de 0 a 12 años

ABSTRACT Objective: Tomographic and anatomic analysis of cervical vertebrae in children from 0 to 12 years of age to verify the possibility of utilization of lateral mass screws. Methods: Twenty-five cervical spine tomographies of children between 0 and 12 years of age, admitted to the emergency room of Hospital das Clínicas of São Paulo were retrospectively analyzed. The following distances were measured: width and length of the lateral masses in the axial section; width and height in the coronal section; height, length and diagonal diameter in the sagittal section. The variables studied were correlated with age and sex and submitted to statistical analysis. Results: The analysis of tomographic measurements of 20 patients showed a correlation between age and dimensions of the lateral mass, which were higher after 6 years of age. In relation to sex, greater measures were observed in males in all axes. With regard to the passage of the screws, we only had 22 masses (11%) that prevented their use. However, when stratified by age, we noticed that no patients had restrictions on the use of the lateral mass screw after the age of 6. Conclusion: This study analyzed the measurements of 200 lateral masses, making it possible to infer that there is an increase of dimensions with age and in males. Through the data, it was possible to affirm that in this sample, considering the implants available in the market, the lateral mass screws could be used in 89% of the lateral masses.

RESUMO Objetivo: Análise tomográfica e anatômica das vértebras cervicais em crianças de zero a doze anos de idade para verificar a possibilidade de passagem de parafuso de massa lateral. Métodos: Foram analisadas retrospectivamente 25 tomografias de coluna cervical de crianças entre 0 e 12 anos de idade, admitidas no pronto socorro do Hospital das Clínicas de São Paulo. Foram aferidas as seguintes medidas: largura e comprimento das massas laterais no corte axial; largura e altura no corte coronal; altura, comprimento e diâmetro diagonal no corte sagital. As variáveis estudadas foram correlacionadas com a idade e o sexo dos indivíduos e submetidas a análise estatística. Resultados: Por meio da análise de medidas tomográficas de 20 pacientes, foi verificada a correlação entre idade e dimensões das massas laterais, sendo estas maiores a partir dos 6 anos. Já em relação ao sexo, foram verificadas medidas maiores no sexo masculino em todos os eixos. Com relação à passagem dos parafusos, tivemos apenas 22 massas (11%) com impossibilidade de uso. Porém, quando estratificados pela idade, notamos não haver pacientes com impedimento para uso do parafuso de massa lateral após os 6 anos. Conclusão: O estudo analisou as medidas de 200 massas laterais, possibilitando inferir que existe aumento das suas dimensões com a idade e no sexo masculino. Através dos dados, foi possível afirmar que nesta amostra, considerando-se os implantes disponíveis no mercado, o parafuso de massa lateral poderia ser utilizado em 89% das massas laterais.

RESUMEN Objetivo: Análisis tomográfico y anatómico de las vértebras cervicales en niños de hasta doce años de edad, para comprobar la posibilidad de pasaje de tornillos de masa lateral. Métodos: Se analizaron retrospectivamente 25 tomografías computarizadas de la columna cervical de niños entre 0 y 12 años de edad, ingresados en el servicio de urgencias del Hospital das Clínicas de São Paulo. Se tomaron las siguientes medidas: anchura y longitud de las masas laterales en corte axial; anchura y altura del corte coronal; altura, longitud y diámetro diagonal en el corte sagital. Las variables se correlacionaron con la edad y el sexo de los individuos y se sometieron a análisis estadístico. Resultados: Mediante el análisis de las mediciones tomográficas de 20 pacientes, se observó la correlación entre la edad y las dimensiones de las masas laterales, que son más grandes a partir de los 6 años de edad. En relación con el sexo, se observaron medidas más altas en los hombres en todos los ejes. En cuanto al paso de los tornillos, encontramos sólo 22 masas (11%) que impidieron su uso. Sin embargo, cuando se estratificó por edad, observamos que no había ningún impedimento para el uso de tornillo de masa lateral después de 6 años de edad. Conclusión: El estudio examinó las medidas de 200 masas laterales, por lo que es posible inferir que hay un aumento de tamaño con la edad y en el sexo masculino. De estos datos, fue posible afirmar que en esta muestra, teniendo en cuenta los implantes disponibles en el mercado, el tornillo de masa lateral podría ser utilizado en el 89% de las masas laterales.