Noncontiguous Injuries Research Articles

Cervical spine injury: A review

The aim of this review is to re-examine the role of cervical spine imaging in the context of new guidelines and technical advances in imaging techniques. MRI and multislice CT technology have made rapid advances. The rapid primary clinical survey should be followed by lateral cervical spine, chest and pelvic radiographs. If a patient is unconscious then CT of the brain and at least down to C3 is very useful. The cranio-cervical scans should be a maximum of 2 mm thickness, and probably less, as undisplaced type II peg fractures, can be invisible even on 1 mm slices with reconstructions. If the lateral cervical radiograph and the CT scan are negative, then MRI is the investigation of choice to exclude instability. Patients with focal neurological deficit, sign of cord or disc injury, and patients whose surgery require pre-operative cord assessment should be imaged by MRI. It is also the investigation of choice for evaluating the complications and late sequela of trauma. If the patient is to have an MRI scan, do a sagittal STIR sequence of the entire vertebral column to exclude non-contiguous injuries, which, since the advent of MRI. Any areas of oedema or collapse then require detailed CT scanning. The aim of this review is to re-examine the role of cervical spine imaging in the context of new guidelines and technical advances in imaging techniques.

Multilevel Spinal Injury: Incidence, Distribution and Neurological Patterns

Introduction: Fractures and dislocation of spine are serious injuries that most commonly occur in young people. Spinal injury at more than one level is not uncommon. Awareness of multilevel injury of the spine and associated neurological patterns is important for the proper initial management of the patient. Methods: This was a prospective observational study carried out in Department of Orthopedics, Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal from February 2012 to September 2013. Sixty cases of age group between 18 to 63 years of traumatic spinal injury were enrolled. Patients were examined clinically and radiographically. Results: Out of 60 patients, multilevel spinal injury occurred in 26 (43.3%) patients; 10 (16.67%) had contiguous spinal injury and 16 (26.67%) had non-contiguous spinal injury. There were 5 type A pattern spinal injury. Contiguous spinal injury most commonly occurred at level L1/L2 (n=4, 40%) and most had Frankel grade E neurology (n=6, 60%) followed by Frankel grade D (n=2, 20%). Non-contiguous lesions most commonly occurred at thoracic spine and had Frankel grade E neurology in most cases (n=10, 16.67%) followed by grade B and C (n= 2, 2.33% each). Conclusion: Multiple spinal injury was a common pattern of injury, which occurred in 26 (43.3%) patients out of 60 patients enrolled in our study. Multilevel spinal injury is common. We should be aware about its occurrence. We should evaluate for multilevel spinal injuries, so as not to miss them, specially non-contiguous injuries, in the patients presenting with spinal injury.

Multilevel Spinal Injury: Incidence, Distribution and Neurological Patterns

Introduction Fractures and dislocation of spine are serious injuries that most commonly occur in young people. Spinal injury at more than one level is not uncommon. Awareness of multilevel injury of the spine and associated neurological patterns is important for the proper initial management of the patient.
 MethodsThis was a prospective observational study carried out in Department of Orthopedics, Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal from February 2012 to September 2013. Sixty cases of age group between 18 to 63 years of traumatic spinal injury were enrolled. Patients were examined clinically and radiographically.
 ResultsOut of 60 patients, multilevel spinal injury occurred in 26 (43.3%) patients; 10 (16.67%) had contiguous spinal injury and 16 (26.67%) had non-contiguous spinal injury. There were 5 type A pattern spinal injury. Contiguous spinal injury most commonly occurred at level L1/L2 (n=4, 40%) and most had Frankel grade E neurology (n=6, 60%) followed by Frankel grade D (n=2, 20%). Non-contiguous lesions most commonly occurred at thoracic spine and had Frankel grade E neurology in most cases (n=10, 16.67%) followed by grade B and C (n= 2, 2.33% each).
 ConclusionMultiple spinal injury was a common pattern of injury, which occurred in 26 (43.3%) patients out of 60 patients enrolled in our study. Multilevel spinal injury is common. We should be aware about its occurrence. We should evaluate for multilevel spinal injuries, so as not to miss them, especialy non-contiguous injuries, in the patients presenting with spinal injury.

Noncontiguous Spine Injury: Is the Risk Increased in Low-Energy Falls?

Noncontiguous Spine Injury: Is the Risk Increased in Low-Energy Falls?

High Burden of Associated Injuries Occurring With Major Fractures of the Talus.

Talus fractures are severe injuries typically occurring after high-energy trauma. As a result, associated injuries to different anatomic sites and organ systems occur with high frequency. The objective of this study was to determine what injuries occur with high incidence in patients presenting with major fractures of the talus and to identify clinical injury patterns that may warrant special attention in these patients. We performed a retrospective review of patients presenting to 3 level 1 trauma centers with fractures of the talar neck, body, or head over a 14-year period. Patient charts were reviewed for associated orthopedic and nonorthopedic injuries identified during the initial patient encounter and hospitalization. In total, 262 fractures in 258 unique patients met criteria for inclusion. Overall, 33.3% of talus fractures occurred in isolation. One or more associated injuries were identified in the remainder of cases (66.7%). The incidence of associated injuries was similar across fracture patterns. Mean total number of injuries per patient was 2.2 (range, 0-15). The ipsilateral foot was the most frequent site of associated orthopedic injury. Noncontiguous injuries occurred in 36% of cases. Lumbar spine injury occurred in 10.5% of cases. Lower extremity vascular injury was uncommon but bore significant association with open talus fractures. Talus fractures are commonly associated with injuries to different anatomic sites and organ systems. A similar rate of lumbar spine trauma may occur with major talus fractures as has been historically associated with calcaneal fractures. Thorough evaluation and a high index of suspicion are necessary when evaluating patients with major fractures of the talus to avoid missing concomitant injuries. Level IV, retrospective case series.

The Prevalence Non-Adjacent Cervical Cord Injury in an Irish Population

Objective: To analyze the prevalence of non-contiguous injury of spinal cord using MRI with a focus on cervical spinal injury patients. Methods: 60 cervical spinal injury patients were reviewed using the NIMIS (National Integrated Medical Imaging System) system. The MR imaging and imaging reports for cervical spinal injury were reviewed in a University Teaching Hospital in West Ireland (45 male and 15 female). The mean age of patients in this population group was 42. They were divided into three groups based on the mechanism of injury; hyperflexion, hyperextension and axial injury as per ASIA guidelines. The presence or absence of non-contiguous spinal injury was confirmed as to whether there was marrow contusion, herniation, or fracture at any area along the spine. During evaluation of spinal injury the cervical spine is often prioritized, however the importance of surveying the entire spine is essential. It has been emphasized that the whole cervical spine including the cervicothoracic junction (CTJ) Results: A total of 9 cases (15%) showed CTJ or upper thoracic spinal injuries defined as C7-L1 injury. 2 of 21 cases revealed obvious fractures in the CTJs or upper thoracic spines. Ligamentous injury in these regions was found in only one case, Traumatic disc herniation in four cases and spinal cord injury in five cases. Nerve impingement was observed in two cases. The incidence of non-contiguous spinal injuries was higher in the axial compression injury group (25%) than in the hyperflexion injury group (21%) or the hyperextension (20%) injury group, highlighting the importance of injury mechanism. Conclusion: Cervical spinal MR showed non-contiguous CTJ or upper thoracic spinal injuries in 28% of the patients with cervical spinal injury. The mechanism of cervical spinal injury did not significantly affect the incidence of the noncontiguous CTJ or upper thoracic spinal injury. Physicians in Ireland should consider imaging other areas of the spine when a cervical spinal injury is suspected.

Role of age and injury mechanism on cervical spine injury tolerance from head contact loading

ABSTRACTObjective: The objective of this study was to determine the influence of age and injury mechanism on cervical spine tolerance to injury from head contact loading using survival analysis.Methods: This study analyzed data from previously conducted experiments using post mortem human subjects (PMHS). Group A tests used the upright intact head–cervical column experimental model. The inferior end of the specimen was fixed, the head was balanced by a mechanical system, and natural lordosis was removed. Specimens were placed on a testing device via a load cell. The piston applied loading at the vertex region. Spinal injuries were identified using medical images. Group B tests used the inverted head–cervical column experimental model. In one study, head–T1 specimens were fixed distally, and C7–T1 joints were oriented anteriorly, preserving lordosis. Torso mass of 16 kg was added to the specimen. In another inverted head–cervical column study, occiput–T2 columns were obtained, an artificial head was attached, T1–T2 was fixed, C4–C5 disc was maintained horizontal in the lordosis posture, and C7–T1 was unconstrained. The specimens were attached to the drop test carriage carrying a torso mass of 15 kg. A load cell at the inferior end measured neck loads in both studies. Axial neck force and age were used as the primary response variable and covariate to derive injury probability curves using survival analysis.Results: Group A tests showed that age is a significant (P < .05) and negative covariate; that is, increasing age resulted in decreasing force for the same risk. Injuries were mainly vertebral body fractures and concentrated at one level, mid-to-lower cervical spine, and were attributed to compression-related mechanisms. However, age was not a significant covariate for the combined data from group B tests. Both group B tests produced many soft tissue injuries, at all levels, from C1 to T1. The injury mechanism was attributed to mainly extension. Multiple and noncontiguous injuries occurred. Injury probability curves, ±95% confidence intervals, and normalized confidence interval sizes representing the quality of the mean curve are given for different data sets.Conclusions: For compression-related injuries, specimen age should be used as a covariate or individual specimen data may be prescaled to derive risk curves. For distraction- or extension-related injuries, however, specimen age need not be used as a covariate in the statistical analysis. The findings from these tests and survival analysis indicate that the age factor modulates human cervical spine tolerance to impact injury.

Assessment of Whole Spine MRI for Multilevel Noncontaguous Spinal Fractures: Incidence, Patterns, and Missed Injuries

Introduction Multi-level non-contiguous spinal injuries are not uncommon and their incidence varies from 1.6 to 77% depending on the type of imaging modality used. Delayed diagnosis and missed spinal injuries in non-contiguous spine fractures have been frequently described which can result in significant pain, deformity and neurological deficit. Mulitlevel injuries patterns have been studied in the past using X-rays and occasionally CT scans. With the growing use of MRI in assessment of spinal trauma scenario the impact of whole spine MRI in evaluation of multilevel injuries have not been assessed in the past. We performed this study to evaluate the impact of using whole spine sagittal MRI in the multilevel spine injuries. Methods Consecutive spinal injury patients treated between 2011 and 2013 were retrospectively evaluated based on clinical and radiographic records. Patient demographics, mode of injury, presence of associated injuries, clinical symptoms and the presence of neurological deficit were studied. Radiographs of the fractured region and whole spine MRI were evaluated for the presence of multi-level injuries We evaluated 484 consecutive patients undergoing whole spine sagittal MRI for multilevel injuries, missed injuries and analyzed the images for specific injury patterns. Results Among 484 patients, ninety five (19.62%) patients had multilevel injuries including 86 (17.76%) with noncontiguous injuries. Five common patterns of non-contiguous spinal injuries between different regions were observed. Pattern I: Cervical and thoracic- 29.1%, Pattern II: Thoracolumbar and lumbosacral - 22.1%, Pattern III: Thoracic and thoracolumbar- 12.8%, Pattern IV: Cervical and thoracolumbar - 9.1% and Pattern V: Lumbosacral and associated injuries- 9.0%. Whole spine MRI scan detected 24 (28.6%) missed secondary injuries of which 5 were unstable. Fall from height was the most common mechanism of injury I in 200 (51.6%), and road traffic accidents contributed to 145 case (37.1%). Neurological deficit was present in 251 patients (64.5%). Complete neurological deficit (ASIA A) was observed in 131 cases(53.3%) while incomplete deficit was present in 120 cases(47.8%). One twenty six patients (32.4%) had associated non-spinal injury including head injury ( n = 19), chest injury ( n = 22), abdomen injury ( n = 4), pelvic injury ( n = 6) and extremity injuries ( n = 75). Conclusion The incidence of multilevel non-contiguous spine injury using whole spine MRI imaging is 17.76%. Five different patterns of multi-level non-contiguous injuries were found with the most common pattern being the cervical and thoracic level injuries. The incidence of missed injuries identified using whole spine MRI was as high as 28.6% and among them the incidence of unstable injuries can be as high as 21%.

Multilevel non-contiguous spinal injuries: incidence and patterns based on whole spine MRI

Multi-level non-contiguous spinal injuries are not uncommon and their incidence varies from 1.6 to 77% depending on the type of imaging modality used. Delayed diagnosis and missed spinal injuries in non-contiguous spine fractures have been frequently described which can result in significant pain, deformity and neurological deficit. The efficacy of whole spine MRI in detecting asymptomatic significant vertebral fractures is not known. Consecutive spinal injury patients treated between 2011 and 2013 were retrospectively evaluated based on clinical and radiographic records. Patients' demographics, mode of injury, presence of associated injuries, clinical symptoms and the presence of neurological deficit were studied. Radiographs of the fractured region and whole spine MRI were evaluated for the presence of multi-level injuries. Among 484 patients, 95 (19.62%) patients had multilevel injuries including 86 (17.76%) with non-contiguous injuries. Five common patterns of non-contiguous spinal injuries were observed. Pattern I: cervical and thoracic--29.1%, Pattern II: thoracolumbar and lumbosacral--22.1%, Pattern III: thoracic and thoracolumbar--12.8 %, Pattern IV: cervical and thoracolumbar--9.1% and Pattern V: lumbosacral and associated injuries--9.0 %. The incidence of intra-regional non-contiguous injuries was 17.4%. Whole spine MRI scan detected 24 (28.6%) missed secondary injuries of which 5 were unstable. The incidence of multilevel non-contiguous spine injury using whole spine MRI imaging is 17.76%. Five different patterns of multi-level non-contiguous injuries were found with the most common pattern being the cervical and thoracic level injuries. The incidence of unstable injuries can be as high as 21% of missed secondary injuries.

Does CT Angiography Matter for Patients with Cervical Spine Injuries?

Cervical injury can be associated with vertebral artery injury. This study was performed to determine the impact of computed tomography (CT) angiography of the head and neck on planning treatment of cervical spine fracture, if these tests were ordered appropriately, and to estimate cost and associated exposure to radiation and contrast medium. This retrospective review included all patients who underwent CT of the cervical spine and CT angiography of the head and neck from January 2010 to August 2011 at one institution. Patients were divided into those with and those without cervical spine fracture seen on CT of the cervical spine. We determined if the CT angiography of the head and neck was positive for vascular injury in the patients with a cervical fracture. Vascular injury treatment and alterations in surgical fracture treatment due to positive CT angiography of the head and neck were recorded. A scan was deemed appropriate if it had been ordered per established institutional protocol. Of the 381 patients who underwent CT angiography of the head and neck, 126 had a cervical injury. Sixteen of the CT angiography studies were appropriately ordered for non-spinal indications, and twenty-three were inappropriately ordered. The CT angiography was positive for one patient for whom the imaging was off protocol and one for whom the indication was non-spinal. Nineteen patients had positive CT angiography of the head and neck; no patient underwent surgical intervention for a vascular lesion. Eleven patients underwent surgical intervention for a cervical fracture; the operative plan was changed because of vascular injury in one case. The CT angiography was positive for eleven of forty-eight patients who had sustained a C2 fracture; this group accounted for eleven of the nineteen positive CT angiography studies. Noncontiguous injuries occurred in nineteen patients; three had positive CT angiography of the head and neck. The approximate charge for the CT angiography was $3925, radiation exposure was approximately 4000 mGy/cm, and contrast-medium load was approximately 100 mL. Positive CT angiography of the head and neck rarely altered surgical treatment of cervical spine injuries. This study supports the findings in the literature that C1-C3 spine injuries have an increased association with vertebral artery injury. CT angiography of the head and neck ordered off protocol had a low likelihood of being positive. Strict adherence to protocols for CT angiography of the head and neck can reduce costs and decrease unnecessary exposure to radiation and contrast medium. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Associated Injuries in Children and Adolescents With Spinal Trauma

Over half of children and adolescents with spinal trauma have associated injuries, most commonly involving the appendicular skeleton, head and neck, and thorax. The incidence and characteristics of these associated injuries have been well described, but to our knowledge there has been no evaluation of the relationship between the injury characteristics and the patient age. Data were obtained from the trauma registries of the local pediatric and adult level 1 trauma centers, and patients aged 0 to 19 years with spinal trauma were identified. For analysis, patients were divided into 3 age groups: 0 to 3, 4 to 12, and 13 to 19 years. Associated injuries were divided into 5 groups: head, thoracic, abdominal, appendicular skeletal fracture, and neurological. Overall, 25 patients had isolated dislocations and 307 patients had 366 spinal fractures or fracture-dislocations: 36% cervical, 31% thoracic, and 51% lumbar. Most (84%) of the injuries occurred in the 13- to 19-year-old group. Sixty-two percent of patients had associated injuries, most commonly thoracic injuries (pulmonary contusion, pneumothorax, rib fracture); 45% had multilevel spinal fractures, 39% of which were noncontiguous. Nearly three fourths of the noncontiguous fractures occurred in a different spinal region; cervical fracture with concomitant thoracic fracture was the most frequent pattern. This large series of consecutive patients highlights several important concepts concerning pediatric spinal fractures, including age-related patterns of injury, frequent associated injuries, and a high rate of multiple spinal injuries, especially noncontiguous injuries. It also emphasizes the importance of careful full-body examination and imaging of the entire spine in children and adolescents with a known spinal injury. Level IV-case series.

Head-First Impact With Head Protrusion Causes Noncontiguous Injuries of the Cadaveric Cervical Spine

To simulate horizontally aligned head-first impacts with initial head protrusion using a human cadaveric neck model and to determine biomechanical responses, injuries, and injury severity. Head-first impacts with initial head protrusion were simulated at 2.4 m/s using a human cadaver neck model (n = 10) mounted horizontally to a torso-equivalent mass on a sled and carrying a surrogate head. Macroscopic neck injuries were determined, and ligamentous injuries were quantified using fluoroscopy and visual inspection after the impacts. Representative time-history responses for injured specimens were determined during impact using load cell data and analyses of high-speed video. Biomechanics research laboratory. Cervical spines of 10 human cadavers. Injury severity at the middle and lower cervical spine was statistically compared using a 2-sample t test (P < 0.05). Neck buckling consisted of hyperflexion at C6/7 and C7/T1 and hyperextension at superior spinal levels. Noncontiguous neck injuries included forward dislocation at C7/T1, spinous process fracture and compression-extension injuries at the middle cervical spine, and atlas and odontoid fractures. Ligamentous injury severity at C7/T1 was significantly greater than at the middle cervical spine. Distinct injury mechanisms were observed throughout the neck, consisting of extension-compression and posterior shear at the upper and middle cervical spine and flexion-compression and anterior shear at C6/7 and C7/T1. Our experimental results highlight the importance of clinical awareness of potential noncontiguous cervical spine injuries due to head-first sports impacts.

Pediatric Noncontiguous Spinal Injuries

Retrospective review. To determine the incidence and clinical characteristics of noncontiguous spinal injuries (NCSI) in a pediatric population. The secondary objective is to identify high-risk patients requiring further imaging to rule out NCSI. NCSI can add significant complexity to the diagnosis, management, and outcome of children. There is very little in the pediatric literature examining the nature, associated risk factors, management, and outcomes of NCSI. All children up to 18 years of age with a spinal injury, as defined by International Classification of Diseases, Ninth Revision codes, at one pediatric trauma hospital were included (n = 211). Data for patient demographics, mechanism of injury, spinal levels involved, extent of neurological injury and recovery, associated injuries, medical complications, treatment, and outcome were recorded. Twenty-five (11.8%) of 211 patients had NCSI, with a median age of 13.0 years (interquartile range = 8-15). The most common pattern of injury was a double thoracic noncontiguous injury. Sixteen percent of the cases of NCSI were initially missed, with no clinical deterioration due to missed diagnosis. Associated injuries occurred in 44% of patients with NCSI. Twenty-four percent of patients with multiple NCSI had a neurological injury compared with 9.7% in patients with single-level or contiguous injuries (P = 0.046). There is a high incidence of children with multiple NCSI who are more likely to experience neurological injuries compared with patients with single-level or contiguous spinal injuries. Patients with a single-level spinal injury on existing imaging with an associated neurological injury should undergo at least plain films of the entire spine to exclude noncontiguous injuries. In patients without neurological injury and a single spinal fracture, radiography showing at least 4 levels above and below the fracture should be performed. All children with spinal injury should have associated injuries carefully excluded.

Traumatismos raquídeos y lesiones no contiguas. Importancia del cribado con resonancia magnética de columna completa en el esguince cervical

IntroductionIn spinal trauma, the nuclear magnetic resonance (NMR) is directed only to the region concerned. Therefore injuries outside this region can go undetected. This paper aims to investigate the incidence and characteristics of lesions outside the spinal segment that, initially, appeared to be traumatized (non-contiguous injuries; NCI). Material and methodsA total of 48 minor cervical spinal injuries, mostly whiplash, are retrospectively studied. In all of them a NMR screening of the entire spine was performed, by using the “composing system” (Siemens). ResultsThe NCI incidence (pattern III) related to the accident was 16.67%. In the whiplash cases, NCI reaches 24.14%, compared to 5.26% in all the remaining cases (P <0.05). If we add whiplash cases, patterns II to III, the sensitivity in detecting NCI reached 44.83% against 36.84% from the other causes. This means that, in almost 45% of whiplash cases, causal or concausal NCI of interest (patterns II and III), were found. ConclusionsThe occurence of NCI in minor spinal injuries is emphasized. The paper discusses its relevance from a health care and medico-legal perspective and the technical possibility to perform a total spine-MRI study as a complementary study of a spinal region. The study also underlines the usefulness of whole-spine screening MRI in spinal injuries when, for welfare reasons or medico-legal assessment, an MRI is indicated.

Assessment for Additional Spinal Trauma in Patients with Cervical Spine Injury

An institutional review board-approved 8-year retrospective trauma registry analysis of cervical spine injuries (CSIs) was done in a Level 1 trauma center. This analysis includes 129 CSI patients (1.3% of trauma admissions). Cervical spine radiographs diagnosed injuries in 71 per cent of CSI patients. Cervical spine radiographs were false negative in 29 per cent of patients, who were found to have CSI on spine CT. Spine CT had 98 per cent sensitivity and detected 45 per cent additional injuries in cervical spine radiograph-positive patients. Spine CT scans were false negative in two patients with soft tissue injury. Cervical spine fractures were isolated in 45 per cent (n = 58) and multilevel in 55 per cent (n = 71) with contiguous fractures in 43 per cent (n = 55) of patients. Injuries involved two adjoining vertebrae in 38 patients and three or more adjoining vertebrae in 7 patients. C1-2 and C5-6 comprised 26 per cent and 20 per cent of all contiguous fractures. The least common was C7-T1, diagnosed in 2 per cent. The most common contiguous fractures were C1-2 in the elderly and C5-6 in children, comprising half of contiguous cervical injuries in the respective age groups. There were 26 (20.2%) noncontiguous injuries: 15 cervical and 11 cervicothoracolumbar. Multiple regions of the vertebral column were involved in 7.8 per cent of CSI patients. Spine CT is the preferred modality to assess CSI. Injuries were isolated in 45 per cent and were multilevel in the remaining CSI patients. Contiguous and noncontiguous injuries involving the cervical and thoracolumbar spine are common. Assessment of the entire spinal column should be done in patients with CSI.

Chance-Type Flexion-Distraction Injuries in the Thoracolumbar Spine: MR Imaging Characteristics

To evaluate retrospectively the magnetic resonance (MR) imaging features of Chance-type flexion-distraction injuries. The authors' institutional review board does not require its approval or patient informed consent for retrospective studies. Imaging data were reviewed retrospectively for 24 patients (15 male, nine female; mean age, 28 years; range, 9-71 years) who had sustained radiographically typical Chance-type flexion-distraction injuries. The posterior vertebral body height remained unchanged or was increased in these patients. Two radiologists recorded a variety of bone and soft-tissue abnormalities seen with MR imaging. Based on consensus, the documented findings were sequentially analyzed to determine their frequencies. Combined bone and soft-tissue injuries occurred in 23 (96%) of 24 patients, were more common than soft-tissue damage alone (one [4%] of 24 patients), and occurred primarily at the thoracolumbar junction. Contiguous vertebral injury was seen in 20 (83%) of 24 patients, usually in the form of anterosuperior vertebral endplate edema, while noncontiguous injury occurred in eight (33%) of 24 patients. Extensive subcutaneous and paraspinal muscle edema was seen in all patients and extended over several segments. Posterior osteoligamentous complex disruption also occurred in all patients. Horizontally oriented fractures of the posterior neural arches produced an MR imaging pattern that the authors call the sandwich sign, which consists of linear hemorrhage framed by marrow edema. This sign was seen in 12 (50%) of 24 patients. In seven (29%) of 24 patients, a fracture line extending from a damaged pedicle was seen to exit through the contralateral posterosuperior aspect of the vertebral body, with extension of the fracture fragments into the spinal canal. A spectrum of features is discernible with MR imaging in Chance-type injuries.

Double noncontiguous cervical spinal injuries.

Double noncontiguous spinal injuries in the same patient, the first at the cervical level and the second at the thoracic or thoracolumbar level are not uncommon. On the other hand the incidence of double noncontiguous cervical injuries in low and these injuries imply complex mechanisms. This study investigates the cases of double noncontiguous cervical lesions in 342 cases of acute cervical injuries. An analysis of 342 patients with cervical injuries found 67 multiple cervical injuries and only 11 cases of double noncontiguous cervical lesions. Double noncontiguous cervical injuries have a frequency of 3.2% in this study and in three cases there were pre-existing benign cervical lesions. A possible spinal biomechanical behaviour during injury can be that the first lesion appears because of the traumatic impact and there is a uniform transmission of the remaining traumatic strain all along the spine. It seems that the propagated force finds a spinal zone where the spinal resistance is diminished and the second spinal lesion can occur. Spinal vulnerability for the second lesion in the same trauma can be caused by a pre-existing benign spinal lesion or by a biomechanical discontinuity because of a particular posture at the traumatic moment. The second lesion in double noncontiguous cervical lesions can appear through a single great impact in pre-existing lesions, double impacts at the same time with injuries at two cervical levels or repeated cervical impacts in very quick succession in the same trauma.

Occult vertebral fractures in ankylosing spondylitis.

A retrospective review of patients with ankylosing spondylitis involved in a blunt trauma. Patients referred to two Level I tra uma centers. To determine the incidence and clinical sequelae in thi s patient population where vertebral injury was diagnosed on a delayed basis. The ankylosed spine is at increased risk for fracture and spinal cord injury. Radiological identification of injury is more difficult than in the normal spine. Over a 5 year period, 21 patients were identified with seven having an occult vertebral fracture not recognized as the primary injury or occurring as a second non-contiguous injury level. In these cases, delay in diagnosis of the occult injury was from 3 to 22 days. Development of secondary neurological deficits occurred in three patients. A high index of suspicion and an appreciation of the extreme instability of a fracture in ankylosing spondylitis must be present.

Multiple non-contiguous injuries of the spine

Forty-seven patients with multiple non-contiguous injuries of the spine were reviewed retrospectively, giving an incidence of 5.4 per cent of 875 spinal injuries. Thirty-three were men and 14 women with an age range of between 16 and 78 years. Twenty-three were treated operatively. The multiple non-contiguous injuries had a more complicated mechanism of injury and tended to be more severe injuries than single-level injuries as they were combined more frequently with injuries of other parts of the body. Being aware of this combination of injuries leads to an earlier diagnosis. Operative reconstruction is recommended.

Multiple Noncontiguous Spine Fractures

The data from a prospective study of 508 spine injuries were reviewed to determine the incidence of multiple noncontiguous spine fractures. All patients were examined at admission and at 1 and 2 years postinjury. This series identified 77 (15.2%) multilevel fractures. Motor vehicle accidents were the primary cause of these fractures. The incidence of neurologic injury was not significantly different between multiple noncontiguous and single fractures. Failure to use seat belts and ejection from the vehicle were the main factors associated with multiple noncontiguous spine injuries. Seven major fracture patterns were identified, which accounted for 60% of these injuries. The prognosis for multilevel spine fractures was not significantly worse that that for single-level injuries.