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Barros Filho TEP supervised the literature review and writing and revised the final version of the manuscript. The aim of this study was to review the literature on cervical spine fractures. The literature on the diagnosis, classification, and treatment of lower and upper cervical fractures and dislocations was reviewed. Fractures of the cervical spine may be present in polytraumatized patients and should be suspected in patients complaining of neck pain. These fractures are more common in men approximately 30 years of age and are most often caused by automobile accidents.
The cervical spine is divided into the upper cervical spine occiput-C2 and the lower cervical spine C3-C7 , according to anatomical differences. Fractures in the upper cervical spine include fractures of the occipital condyle and the atlas, atlanto-axial dislocations, fractures of the odontoid process, and hangman's fractures in the C2 segment. These fractures are characterized based on specific classifications. In the lower cervical spine, fractures follow the same pattern as in other segments of the spine; currently, the most widely used classification is the SLIC Subaxial Injury Classification , which predicts the prognosis of an injury based on morphology, the integrity of the disc-ligamentous complex, and the patient's neurological status.
It is important to correctly classify the fracture to ensure appropriate treatment. Nerve or spinal cord injuries, pseudarthrosis or malunion, and postoperative infection are the main complications of cervical spine fractures.
Fractures of the cervical spine are potentially serious and devastating if not properly treated. Achieving the correct diagnosis and classification of a lesion is the first step toward identifying the most appropriate treatment, which can be either surgical or conservative. The most common causes of cervical spine injury are automobile accidents, followed by diving into shallow water, firearm injuries, and sports activities 1 , 2. There is a bimodal age distribution among patients with spinal cord injuries: the first peak occurs in patients between 15 and 24 years, and the second in patients over 55 years of age 2 - 4.
Extension of the upper part of the cervical spine is limited mainly by the transverse portion of the alar ligaments. When flexion is added to the head rotation, the alar ligament is maximally dilated and the cervical spine becomes more vulnerable to injury 5. The first description of occipital condyle fractures in the literature was provided by Bell 6 in , and the second was not published before 7.
Further cases were published from 8 - 11 to 12 , with this type of fracture characterized as very rare. Fractures of the occipital condyle require conservative treatment. Outcomes are favorable if there are no other associated injuries, such as those caused by cranioencephalic trauma or cervical vertebral fractures In general, this type of fracture is caused by accidents involving high-energy traumas, such as sports-related injuries and, in the vast majority of cases, automobile accidents In addition, these fractures generally affect younger individuals in the second and third decades of life, particularly males In , Dvorak and Panjabi 5 published their study on the functional anatomy of the alar ligaments, and in , Anderson and Montesano 13 proposed a classification for fractures of the occipital condyle according to the regional anatomy, biomechanics of the structures involved, and fracture morphology.
Three types of occipital condyle fractures have been described. Type I is an impact fracture of the occipital condyle for which the trauma mechanism is the axial load of the skull on the atlas. In this fracture, there is communication of the occipital condyle with or without minimum deviation of the fragments toward the foramen magnum.
The tectorial membrane remains intact, as does the alar ligament contralateral to the fracture, which ensures the fracture's stability. Type II fractures are part of a cranial base fracture that causes a fracture line extending towards the foramen magnum. This fracture is caused by direct regional trauma and is stable because the alar ligaments and the tectorial membrane remain intact. In type III fractures, there is a fracture-avulsion of the occipital condyle by the alar ligament, which is caused by a rotation of the head, a lateral tilt of the head, or both movements together.
In this case, because the contralateral alar ligament and the tectorial membrane do not remain intact, the injury is potentially unstable. The clinical signs of occipital condyle fractures are highly non-specific, which makes diagnosis difficult. The patient generally only complains of pain on the posterior side of the neck and cervical paravertebral muscle spasms Because specific exams are needed to diagnose these fractures, they often go unnoticed.
The patient may present with persistent pain in the posterior cervical region accompanied by muscle spasms over long periods, without ever suspecting that there is an injury 11 , These fractures are extremely difficult to detect using conventional radiographic techniques, so the use of other methods is necessary. Computed tomography CT is the preferred examination method 11 , The occipitocervical transition should be carefully evaluated, particularly in patients with associated facial and cranial traumas 11 , Cranioencephalic trauma occurs in the vast majority of patients with these fractures, which contributes to the clinical symptoms of these patients, making diagnosis difficult and often leading to death.
There is a possible association of these injuries with fractures of the cervical vertebrae, and occipital condyle fractures are often mistakenly diagnosed as cervical vertebral fractures 11 , Conservative treatment of occipital condyle fractures results in good outcomes; the patient becomes free of neck pain, and full range of motion of the segment involved can be regained after three months of treatment. The use of a Philadelphia cervical collar is recommended for cases categorized as type I or II in the Anderson and Montesano classification, and a more rigid immobilization, such as a halo brace or Minerva cast for 12 weeks, is recommended in the case of type III fractures.
If radiographic images indicate instability after an appropriate period of immobilization with a halo brace, occiput-C2 arthrodesis may be necessary 13 , Pressure exerted on the atlas may lead not only to fracture of the arches but also to rupture of the transverse ligament, which is the main structure that gives this vertebra its anterior stability and prevents it from slipping on the axis 5.
Thus, in Jefferson fractures, the status of the transverse ligament is essential to the prognosis. The diagnosis of an atlas fracture is made by observation of the C 1 -C 2 joint in frontal radiographs. Normally, there should be continuity of the vertical line traced on the lateral margins of the lateral masses of the atlas and of the joint masses of the axis; however, when there is a fracture of the anterior and posterior arches of the atlas, this continuity disappears due to splitting of the lateral masses.
It has yet to be determined how much of a separation is consistent with the integrity of the transverse ligament. Experimental studies on cadavers 14 have demonstrated that if the separation is greater than 7 mm, rupture of the ligament has occurred with C 1 -C 2 instability, which continues even after consolidation of the arch fractures and results in a greater risk of C 1 -C 2 dislocation; this is also true for small traumas 5.
The treatment indicated for Jefferson fractures is reduction by cranial traction and immobilization for three to four months. However, in cases where there is rupture of the transverse ligament, immediate occipito-cervical arthrodesis is necessary.
Sometimes, routine radiographic study of the Jefferson fracture only reveals a fracture of the posterior arch, while a fracture of the anterior arch only appears on CT scans. Patient survival following dislocations between the occiput and the atlas is rare.
We do not have any personal experience with these cases, and there have been very few reports in the literature Pure C 1 -C 2 dislocations, i. Subluxations determined by existing instability are more common, as in dysplasias of the odontoid dens and rheumatoid arthritis We should also differentiate between this and other types of injury, such as Grisel's syndrome, in which a fixed rotatory subluxation of C1-C2 can be observed, which is of an inflammatory origin and with a distinct previous history.
Radiographic diagnosis of a C 1 -C 2 dislocation is typically made in the profile view, in which the distance between the posterior margin of the anterior arch of the atlas and the anterior margin of the odontoid peg is greater than 3 mm in adults or 5 mm in children. If there is uncertainty, the recommendation is to conduct radiographic imaging in the profile view, in both flexion and extension; normally, there should be no significant difference in the distance.
In this dynamic study, especially when a dislocation is suspected, precautions should be taken; for example, complaints of pain should be interpreted as a limitation of movement, and the exam should not be performed on unconscious patients In cases of C 1 -C 2 dislocations, the treatment should always be surgical.
C1-C2 arthrodesis can be performed using various methods: wire fixation between the posterior arches of C1-C2; transarticular fusion of C1-C2 Magerl technique ; the Harms technique, in which a screw is placed in the lateral mass of C1 and in the pedicle of C2; or the Wright technique, in which a screw is placed in the lateral mass of C1 and intralaminarly in C2 Recent anatomical studies show that, with more modern techniques, surgical treatment is even a possibility in children The mechanism of these fractures is not clear 19 , but biochemical studies suggest that they are caused by shear forces If there is a hyperflexion component to the fracture, then an anterior deviation with anterior dislocation of the atlas can occur.
This injury is known as a C 1 -C 2 fracture dislocation. In this case, there is a higher possibility of spinal cord integrity than in pure dislocation; therefore, the probability of survival is greater. If the odontoid dens fracture occurs by hyperextension, there may be posterior deviation In radiographic studies of fractures without deviation, whether in the anteroposterior or profile views, only the fracture line of the odontoid peg fracture will be visible, whereas in fractures with deviation, the fracture will be visible with deviation of the distal fragment and dislocation of the atlas.
In fractures without deviation, it is sometimes very difficult to see the fracture line, and diagnosis is only possible with CT imaging. Special care should be taken with children when performing a radiological diagnosis of fractures without deviation because vertebral ossification is incomplete.
In radiographs of children, the odontoid process and the body of the axis are separated by a strip of tissue that is transparent to X-rays. This strip of tissue becomes progressively narrower until it disappears in year-olds 19 , Treatment is guided by the type of odontoid fracture 19 - Type I fractures that do not involve injury to the ligament structures supporting the atlanto-occipital joint can be treated with cervical arthrodesis for three months.
There is some debate as to the best treatment of type II fractures due to the documented poor potential for consolidation of the fracture in elderly patients and the known morbidity associated with prolonged treatment with a halo brace 19 - Relative indications for surgery include the following 20 - 22 :. In fractures requiring surgical treatment, an alternative is osteosynthesis with the use of a cannulated screw. In this technique, a radioscopy-guided anterior incision is made at C4-C5 with dissection and placement of a guide wire in the inferior cortex of C2.
A cannulated screw is then inserted with the assistance of simultaneous images in the anteroposterior and profile views 19 - Contraindications for this technique include the following: osteoporosis, comminuted fractures, unfavorable fracture line angulation oblique anterior line , diastasis of the fragments, and pseudoarthrosis.
Traumatic spondylolisthesis of the axis, also known as hangman's fracture, is the typical fracture resulting from hyperextension-distraction in which there is a fracture of the pedicle of C 2 with dislocation of the body of this vertebra on C 3 This fracture, despite the major dislocation of C 2 on C 3 that often occurs, rarely leads to spinal cord injury because it causes the canal to widen rather than narrow The Levine and Edwards classification 24 divides traumatic spondylolisthesis of the axis into four types:.
Type I: fracture without an angular deviation and translational deviation of less than 3. Type II: fracture with a significant translational or angular deviation that occurs due to hyperextension and axial compression combined with a mechanism of flexion-compression;. Type IIa: fracture with a small translational deviation and wide angulation, with an increase in posterior disc space between C2-C3 upon application of traction that occurs due to a flexion-distraction; and.
Type III: fracture with a large translational and angular deviation, which is associated with unilateral or bilateral dislocation of the C2-C3 joint facets and occurs due to a flexion-compression mechanism. Type I fractures are stable injuries and can be treated with the use of a neck brace, halo-cast, halo-vest, or Minerva cast for a period of 12 weeks.
Type II fractures are unstable injuries, and the mechanism by which the fracture is produced requires a reduction through distraction and slight hyperextension with posterior immobilization and application of a halo-cast for 12 weeks.
In type IIa fractures, cranial traction is indicated so that reduction can be achieved by means of slight compression and extension, as flexion-distraction is the probable injury mechanism. These fractures should be treated with a halo-cast for 12 weeks or surgically stabilized by means of C2-C3 anterior arthrodesis or transpedicular fixation of C2.
Surgical treatment is indicated in type III fractures and is aimed at reduction of the joint facets and stabilization by arthrodesis Previously, the most commonly used classifications of cervical fractures were those of Allen-Ferguson 25 and the AO. More recently, the SLIC classification 26 has added neurological status as another factor to consider. The Allen-Ferguson classification was one of the first classifications to be used, but its importance today is only historical.
It divides injuries into six types 23 : compression-flexion, vertical compression, distraction-flexion, compression-extension, distraction-extension, and lateral flexion Still widely used by various centers, the classification of lower cervical fractures recommended by the AO group consists of three types A, B and C , which are extended into groups and subgroups.
Princípios e Práticas de Ventilação Mecânica em Pediatria e Neonatologia
Ship maneuvering digital simulator ; Simulador digital de manobras de navios. Escola Politecnica. This paper reports on two case studies making use of a digital simulator to investigate the maneuvering motions of ships in canals with shallow and restricted waters. The first case study corresponds to a maneuvering analysis conducted for the Port of Rio Grande RS - Brazil , whose aim was to assess the potential impact upon maneuvers of the presence of a large offshore platform the PETROBRAS P which is to remain docked for several months at the Port to complete its construction. The second study made use of the simulator to evaluate the maneuvering conditions along the approach route and maneuvering basin of the Port of Ponta do Felix PR - Brazil. The simulator includes a complete mathematical model of the ship dynamics in the horizontal plane when subjected to wind and current forces.
16th International Conference on Information Technology-New Generations (ITNG 2019)
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