Odontoid fractures are the most common upper cervical spine fracture. There are two mechanisms in which odontoid fractures occur, most commonly hyperflexion of the neck resulting in displacement of the dens anteriorly and hyperextension resulting in posterior dens displacement. Type 2 fractures are the most common and are associated with significant non-union rates after treatment. One possible consequence of an odontoid fracture is a synovial cyst, resulting in spinal cord compression, presenting as myelopathy or radiculopathy. Synovial cysts as a result of spinal fracture, usually of the facet joint, are most common in the lumbar region, followed by the thoracic and then cervical region; cervical cysts are rare. Fracture and subsequent cyst formation is thought to be related to hyper-motion or trauma of the spine. This is reinforced by the appearance of spinal synovial cysts most commonly at the level of L4/5; this being the region with the biggest weight-bearing function. The most common site of cervical cyst formation is at the level of C7/T1; this is a transitional joint subjected to unique stress and mechanical forces not present at higher levels. Treatment of a cervical synovial cyst at the level of the odontoid is challenging with little information available in the literature. The majority of cases appear to implement posterior surgical resection of the cyst, with fusion of adjacent cervical vertebrae to stabilise the fracture, resulting in restricted range of movement.
We describe a case concerning a 39-year-old female who presented with uncertain cause of odontoid fracture, resulting in a cystic lesion compressing the upper cervical spinal cord.
Minimal invasive surgery of C1/C2 transarticular fusion was successfully performed resulting in significant improvement of neurological symptoms in this patient. At 1-year follow-up, the cyst had resolved without surgical removal and this was confirmed by radiological measures.
Transarticular fusion; Odontoid fracture; Cervical cyst; Cystic lesion
Prospective, observational case series evaluating the value of cervical spine computed tomography (CT) scans in the initial evaluation of a helmeted football player with suspected cervical spine injury.
Five asymptomatic male football players, fully equipped and immobilized on a backboard.
Multiple 3.0-mm, helically acquired, axially displayed CT images of the cervical spine were obtained from the skull base inferiorly through T1, with images filmed at soft tissue and bone windows. Sagittal and coronal reformatted images were performed. Software was used to minimize metallic artifact.
All series were reviewed by a Board-certified neuroradiologist for image clarity and diagnostic capability.
Lateral scout films demonstrated mild segmental degradation, depending on the location of the metallic snaps overlying the spine. Anteroposterior scout films and bone window images were of diagnostic quality. The soft tissue windows showed minimal localized artifact occurring at the same levels as in the lateral scout views. This minimal beam-hardening streak artifact did not affect the diagnostic quality of the soft tissue windows. Reconstructed images were uniformly of clinical diagnostic quality.
When CT scans were reviewed as a unit, sufficient information was available to allow reliable clinical decisions about the helmeted football player. In light of recent publications demonstrating the difficulty of obtaining adequate radiographs to evaluate cervical spine injury in equipped football players, helmeted athletes may undergo CT scanning without any significant diagnostic limitations.
helmet removal; cervical spine; trauma; injury
Concomitant traumatic injuries in the upper cervical spine are often encountered and rarely reported. We examined the data concerning 784 patients with cervical spine injuries following trauma, including 116 patients with upper cervical spine injuries. Twenty-six percent of patients with upper cervical spine injuries (31 cases) were found to have combined injuries involving either the upper or the upper and lower cervical spine. The frequent patterns were combined type I bipedicular fracture of the axis and dens fracture, and combined dens fracture and fracture of the posterior arch of C1. Other patterns posed specific problems, such as combined dens and Jefferson fracture and combined dens and C2 articular pillar fracture. Seventy percent of atlas fractures, 30% of C2 traumatic spondylolistheses and 30% of dens fractures were part of a combination. A total of 1.7% of patients with lower cervical spine injuries had a combined injury in the upper cervical spine. A comprehensive therapeutic schedule is outlined. Combined injuries in the upper cervical spine should be sought in any patient with a cervical spine injury.
Key words Spine; Cervical ¶vertebrae; Spinal fractures; Spinal ¶injury; Atlas; Axis
Serious cervical spinal injuries in organized youth football are rare. Cervical fracture with neurologic injury is rarely reported in organized youth football players with no pre-existing risk fractures for transient tetraplegia.
Case report and literature review.
After being improperly tackled by an opponent of significantly larger body size, a player sustained a C7 posterior cervical fracture with transient tetraplegia. He was immobilized in a cervical collar and sent to a level 1 trauma center for evaluation. Initial examination showed bilateral paresthesia of the limbs with normal motor function (ASIA D). Initial radiographs of the cervical spine showed a displaced extension-compression fracture of the C7 spinous process. Magnetic resonance imaging of the cervical spine showed edema in the spinal cord in the region of the injury along with significant posterior injury. Imaging studies showed normal volumetric measurements of the spinal canal and no pre-existing risk factors for spinal stenosis or spinal cord injury. Radiographs showed that cervical fracture was healed at 9-month follow-up examination. At 1-year follow-up, the patient was asymptomatic. Radiographs showed healed fracture with no residual instability and full range of cervical spine motion on flexion–extension views.
This case underscores the potential for serious cervical spinal injuries in organized youth sports when players are physically overmatched, and improper tackling technique is used.
Youth football; Sports injuries; Spinal injury; Cervical; Tetraplegia, transient; Neurapraxia; Fracture, cervical, hyperextension; Spinal stenosis, congenital
Atlantoaxial rotatory fixation (AARF) in adult is a rare disorder that occurs followed by a trauma. The patients were presented with painful torticollis and a typical 'cock robin' position of the head. The clinical diagnosis is generally difficult and often made in the late stage. In some cases, an irreducible or chronic fixation develops. We reported a case of AARF in adult patient which was treated by immobilization with conservative treatment. A 25-year-old female was presented with a posterior neck pain and limitation of motion of cervical spine after a traffic accident. She had no neurological deficit but suffered from severe defect on the scalp and multiple thoracic compression fractures. Plain radiographs demonstrated torticollis, lateral shift of odontoid process to one side and widening of one side of C1-C2 joint space. Immobilization with a Holter traction were performed and analgesics and muscle relaxants were given. Posterior neck pain and limitation of the cervical spine's motion were resolved. Plain cervical radiographs taken at one month after the injury showed that torticollis disappeared and the dens were in the midline position. The authors reported a case of type I post-traumatic AARF that was successfully treated by immobilization alone.
Atlanotaxial subluxation; Adult patient; Radiography; Rotatory fixation; Conservative management; Torticollis
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.
Cervical Atlas; Cervical Vertebrae; Spinal Fractures; Classification; Therapeutics
Controversy continues as to the most safe and reliable method for clearing the cervical spine (C-spine) in a trauma patient who is rendered unable to participate in a clinical examination. Although magnetic resonance imaging (MRI) is the most sensitive test to detect soft-tissue injuries, it is impractical for routine use in every patient largely because of its cost and time of acquiescence. Recent studies have advocated the sole use of multidetector computed tomographic (MDCT) scans of the C-spine to decide if cervical collar immobilization can be discontinued. The current investigation retrospectively reviewed a series of MDCT scans obtained after an acute traumatic event that were used to direct treatment in the emergency department (ED) or intensive care unit.
Seven-hundred and eight trauma patients consecutively admitted to the ED between June 2001 and July 2006 underwent a computed tomographic scan of their C-spine as part of an institutional protocol. We identified 91 patients with MDCT scans that were officially recorded as adequate and negative by an attending ED radiologist who had also undergone an MRI during the same trauma admission period. Retrospectively, two fellowship-trained spine surgeons independently reviewed these MDCT studies to address the following questions: (1) Is the study adequate? (2) Is it suggestive of an acute injury? (3) Is there sufficient information to safely recommend collar removal? Institutional Review Board approval was obtained before the images were reviewed. Neither clinical examination findings nor MRI readings were made available to the surgeon evaluators.
Both spine surgeons agreed that 76 of the 91 studies (84%) were adequate to evaluate for possible C-spine injuries. Seven of 91 MDCT scans (8%) were deemed inadequate by both surgeons (95% confidence interval, 2.3–13.1). Reasons for inadequacy included motion artifact, insufficient visualization of the cervical-thoracic or occipital-cervical junctions, incomplete reconstructive views, or poor quality. Three of the adequate MDCT scans had fractures that were identified by both of the spine surgeons; 4 additional fractures and 15 findings suspicious for instability were identified by at least one of the surgeons. Ultimately, 22 of 91 MDCT scans read as adequate and normal by attending radiologists were deemed suspicious for abnormality by the spine surgeons. Of these 22 cases, the official MRI reading was positive for a trauma-related abnormality in 17 cases.
C-spine clearance of patients without the ability participate in a clinical examination remains difficult. A multidisciplinary, algorithmic approach generally yields the most consistent results. However, our data highlight that reliance on a single imaging modality may lead to missed diagnosis of C-spine injuries. These data suggest that early involvement of the spine service for radiographic clearance may help identify occult injuries or suspicious findings necessitating further evaluation.
Cervical spine; Trauma; Clearance; Multidetector computed tomographic scan; Cervical collar
The management of patients with subaxial cervical injuries lacks consensus, particularly in regard to the decision which surgical approach or combination of approaches to use and which approach yields the best clinical outcome in the distinct injury. The trauma literature is replete with reports of surgical techniques, complications and gross outcome assessment in heterogeneous samples. However, data on functional and clinical outcome using validated outcome measures are scanty. Therefore, the authors performed a study on plated anterior cervical decompression and fusion for unstable subaxial injuries with focus on clinical outcome. For the purpose of a strongly homogenous subgroup of patients with subaxial injuries without spinal cord injuries, robust criteria were applied that were fulfilled by 28 patients out of an original series of 131 subaxial injuries. Twenty-six patients subjected to 1- and 2-level fusions without having spinal cord injury could be surveyed after a mean of 5.5 years (range 16–128 months). The cervical spine injury severity score averaged 9.6. Cross-sectional outcome assessment included validated outcome measures (Neck pain disability index, Cervical Spine Outcome Questionnaire, SF-36), the investigation of construct failure and successful surgical outcome were defined by strict criteria, the reconstruction and maintenance of local and total cervical lordosis, adjacent-segment degeneration and intervertebral motion, and the fusion-rate using an interobserver assessment. Self-rated clinical outcome was excellent or good in 81% of patients and moderate or poor in 19% that corresponded to the results of the validated outcome measures. Results of the NPDI averaged 12.4 ± 12.7% (0–40). With the SF-36 mean physical and mental component summary scores were 47.0 ± 9.8 (18.2–59.3) and 52.2 ± 12.4 (14.6–75.3), respectively. Using merely non-constrained plates, construct failure was observed in 31% of cases and loss of local lordosis, expressed as a mean injury angle of 14°, postoperative angle of −5.5° and follow-up angle of −1°, was significant. However, total cervical lordosis was within the limits of normalcy (−24.3° ± 13.3) and fusion-rate was 88.5%. The progression of adjacent-level degeneration was shown to be significantly influenced by a decreased plate-to-disc-distance. Adjacent-level intervertebral motion was not altered due to the adjacent fusion, but reduced in the presence of advanced adjacent-level degeneration. Patients were more likely to maintain a high satisfaction level if they succeeded to maintain segmental lordosis (<0°), had a solid fusion, an increased plate-to-disc distance, and if they were judged to have a successful surgical outcome that included the absence of construct failure and reconstruction of lordosis within ±1 SD of normalcy. Using validated outcome vehicles the interdependencies between radiographical, functional and clinical outcome parameters could be substantiated with statistically significant correlations. The use of validated outcome vehicles in a subgroup of patients with plated anterior cervical fusions for subaxial injuries is recommended. With future studies, it enables objective comparison of surgical techniques and related radiographical, functional and clinical outcome.
Electronic supplementary material
The online version of this article (doi:10.1007/s00586-008-0879-3) contains supplementary material, which is available to authorized users.
Cervical spine; Injury; Subaxial; Outcome; Instrumentation
We wished to evaluate the incidence of non-contiguous spinal injury in the cervicothoracic junction (CTJ) or the upper thoracic spines on cervical spinal MR images in the patients with cervical spinal injuries.
Materials and Methods
Seventy-five cervical spine MR imagings for acute cervical spinal injury were retrospectively reviewed (58 men and 17 women, mean age: 35.3, range: 18-81 years). They were divided into three groups based on the mechanism of injury; axial compression, hyperflexion or hyperextension injury, according to the findings on the MR and CT images. On cervical spine MR images, we evaluated the presence of non-contiguous spinal injury in the CTJ or upper thoracic spine with regard to the presence of marrow contusion or fracture, ligament injury, traumatic disc herniation and spinal cord injury.
Twenty-one cases (28%) showed CTJ or upper thoracic spinal injuries (C7-T5) on cervical spinal MR images that were separated from the cervical spinal injuries. Seven of 21 cases revealed overt fractures in the CTJs or upper thoracic spines. Ligament injury in these regions was found in three cases. Traumatic disc herniation and spinal cord injury in these regions were shown in one and two cases, respectively. The incidence of the non-contiguous spinal injuries in CTJ or upper thoracic spines was higher in the axial compression injury group (35.3%) than in the hyperflexion injury group (26.9%) or the hyperextension (25%) injury group. However, there was no statistical significance (p > 0.05).
Cervical spinal MR revealed 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 non-contiguous CTJ or upper thoracic spinal injury.
Spine, MR; Spine, injuries; Trauma
Anterior cervical discectomy and fusion (ACDF) is currently treatment of choice for managing medical therapy refractory cervical degenerative disc disease. Numerous studies have demonstrated the effectiveness of ACDF; patients generally experience rapid recoveries, and dramatic improvement in their pain and quality of life. However, as several studies reported symptomatic adjacent segment disease attributed to fusions’ altered kinematics, cervical disc arthroplasty emerged as a new motion-sparing alternative to fusion. Fusion at one level increases motion at adjacent levels along with increased intradiscal pressures. This phenomenon can result in symptomatic adjacent level degeneration, which can necessitate reoperation at these levels. The era of cervical arthroplasty began in Europe in the late 1990s. In recent years, artificial cervical disc arthroplasty (ACDA) has been increasingly used by spine surgeons for degenerative cervical disc disease. There have been several reports of safety, efficacy and indications of ACDA.
Cervical arthroplasty offers several theoretical advantages over anterior cervical discectomy and fusion (ACDF) in the treatment of selected patients with medically refractory cervical radiculopathy. Preserving motion at the operated level, cervical TDR has the potential to decrease the occurrence of adjacent segment degeneration.
There are a few studies on the efficacy and effectiveness of ACDA compared to cervical fusion. However, the true scenery of cervical arthroplasty yet to be identified.
This study is intended to define patients' characteristics and outcomes of ACDA by a single surgeon in Iran.
This retrospective study was performed in two general Hospitals in Tehran, Iran from 2005 To 2010. All patients were operated by one senior neurospine surgeon. One hundred fifty three patients were operated in this period. All patients signed the informed consent form prior to surgery. All patients presented with cervical discopathy who had myelopathy or radiculopathy and failed conservative management, undergoing cervical disc arthroplasty by ACDA were included, consecutively. Patients were followed for at least 2 years.
Exclusion criteria was age greater than 60 years, non compliance with the study protocol, osteoporosis, infection, congenital or post traumatic deformity, malignancy metabolic bone disease, and narrow cervical canal (less than 12 mm). Heterotopic ossification and adjacent segment degenerative changes were assessed at 2 years follow up by means of neutral and dynamic xrays and CT/MRI if clinically indicated. Neck and upper extremity pain were assessed before the procedure and in the first post-operative visit and 3 months later by means of visual analogue scale.
A standard approach was performed to the anterior cervical spine. Patients were positioned supine while holding neck in neutral position. A combination of sharp and blunt dissection was performed to expose longus coli musculature and anterior cervical vertebrae. Trachea and esophagus were retracted medially and carotid artery and jugular vein laterally. After a thorough discectomy, the intersomatic space is distracted in a parallel way by a vertebral distracter. Followed by Caspar distractor is applied to provide a working channel into posterior disc space. In this stage, any remnant disc materials as well as osteophytes are removed and foraminal decompression is done. Posterior longitudinal ligament (PLL) opening and removal, although discouraged by some, is done next. In order to define the size of the prosthesis, multiple trials are tested. It is important not to exceed the height of the healthy adjacent disc to avoid facet joint overdistraction. An specific insertor is applied to plant the prosthesis in disc space. Control X-rays are advised to check the precise positioning of the implant.
one hundred-fifty three patients including 87 females and 66 males were included. The mean age was 41 for females and 42 for males. Affected level was C5-C6 in 81 cases, C6-C7 in 72 cases and C4-C5 in 10 cases. The most common applied ACDA was DiscoCerv which was inserted in 127 cases followed by prodisc-c in three patients and Baguera in thirty three psatients.Ten cases had two levels involvement. Both neck and upper extremity pain improved significantly in early and late post op assessments compared to pre-op. There was only one operative complication of quadriparesis which might be attributed to the iatrogenic cervical spinal trauma.
Cervical disc arthroplasty has been advocated to address drawbacks of fusion including loss of motion segment and adjacent level degeneration; our study along with several other reports provide considerable evidence in this regard. Cervical disc arthroplasty is a safe and effective alternative for fusion in cervical degenerative disc disease.
Cervical degenerative disc disease, Artificial cervical disc arthroplasty, Safety, Efficacy
Cervical disc prostheses induce significant amount of artifact in magnetic resonance imaging which may complicate radiologic follow-up after surgery. The purpose of this study was to investigate as to what extent the artifact, induced by the frequently used Discover® cervical disc prosthesis, impedes interpretation of the MR images at operated and adjacent levels in 1.5 and 3 Tesla MR.
Ten subsequent patients were investigated in both 1.5 and 3 Tesla MR with standard image sequences one year following anterior cervical discectomy with arthroplasty.
Two neuroradiologists evaluated the images by consensus. Emphasis was made on signal changes in medulla at all levels and visualization of root canals at operated and adjacent levels. A “blur artifact ratio” was calculated and defined as the height of the artifact on T1 sagittal images related to the operated level.
The artifacts induced in 1.5 and 3 Tesla MR were of entirely different character and evaluation of the spinal cord at operated level was impossible in both magnets. Artifacts also made the root canals difficult to assess at operated level and more pronounced in the 3 Tesla MR. At the adjacent levels however, the spinal cord and root canals were completely visualized in all patients. The “blur artifact” induced at operated level was also more pronounced in the 3 Tesla MR.
The artifact induced by the Discover® titanium disc prosthesis in both 1.5 and 3 Tesla MR, makes interpretation of the spinal cord impossible and visualization of the root canals difficult at operated level. Adjusting the MR sequences to produce the least amount of artifact is important.
Magnetic resonance imaging; Artifact; Cervical disc prostheses; Titanium
To report on a novel technique for providing artifact-free quantitative 4DCT image datasets for breathing motion modeling.
Commercial clinical four-dimensional computed tomography (4DCT) methods have trouble managing irregular breathing. The resulting images contain motion-induced artifacts that can distort structures and inaccurately characterize breathing motion. We have developed a novel scanning and analysis method for motion-correlated CT that utilizes standard repeated fast helical acquisitions, a simultaneous breathing surrogate measurement, deformable image registration, and a published breathing motion model.
The motion model differs from the CT-measured motion by an average of 0.72 mm, indicating the precision of the motion model. The integral of the divergence of one of the motion model parameters is predicted to be a constant 1.11 and is found in this case to be 1.09, indicating the accuracy of the motion model.
The proposed technique shows promise for providing motion-artifact free images at user-selected breathing phases, accurate Hounsfield units, and noise characteristics similar to non-4D CT techniques, at a patient dose similar to or less than current 4DCT techniques.
4DCT; Breathing Motion Modeling; radiation therapy
Anterior odontoid screw fixation or posterior C1-2 fusion techniques are routinely used in the treatment of Type II odontoid fractures, but these techniques may be inadequate in some types of odontoid fractures. In this new technique (Kotil technique), through a posterior bilateral approach, transarticular screw fixation was performed at the non-dominant vertebral artery (VA) side and posterior transodontoid fixation technique was performed at the dominant VA side. C1-2 complex fusion was aimed with unilateral transarticular fixation and odontoid fixation with posterior transodontoid screw fixation. Cervical spinal computed tomography (CT) of a 40-year-old male patient involved in a motor vehicle accident revealed an anteriorly dislocated Type II oblique dens fracture, not reducible by closed traction. Before the operation, the patient was found to have a dominant right VA with Doppler ultrasound. He was operated through a posterior approach. At first, transarticular screw fixation was performed at the non-dominant (left) side, and then fixation of the odontoid fracture was achieved by directing the contralateral screw (supplemental screw) medially and toward the apex. Cancellous autograft was scattered for fusion without the need for structural bone graft or wiring. Postoperative cervical spinal CT of the patient revealed that stabilization was maintained with transarticular screw fixation and reduction and fixation of the odontoid process was achieved completely by posterior transodontoid screw fixation. The patient is at the sixth month of follow-up and complete fusion has developed. With this new surgical technique, C1-2 fusion is maintained with transarticular screw fixation and odontoid process is fixed by concomitant contralateral posterior transodontoid screw (supplemental screw) fixation; thus, this technique both stabilizes the C1-2 complex and fixes the odontoid process and the corpus in atypical odontoid fractures, appearing as an alternative new technique among the previously defined C1-C2 fixation techniques in eligible cases.
Odontoid fracture; posterior transodontoid; screw fixation kotil technique
We describe a cardiac gated high in-plane resolution axial human cervical spinal cord diffusion tensor imaging (DTI) protocol. Multiple steps were taken to optimize both image acquisition and image processing. The former includes slice-by-slice cardiac triggering and individually tiltable slices. The latter includes (i) iterative 2D retrospective motion correction, (ii) image intensity outlier detection to minimize the influence of physiological noise, (iii) a non-linear DTI estimation procedure incorporating non-negative eigenvalue priors, and (iv) tract-specific region-of-interest (ROI) identification based on an objective geometry reference. Using these strategies in combination, radial diffusivity (λ⊥) was reproducibly measured in white matter (WM) tracts (adjusted mean [95% confidence interval]=0.25 [0.22, 0.29]µm2/ms), lower than previously reported λ⊥ values in the in vivo human spinal cord DTI literature. Radial diffusivity and fractional anisotropy (FA) measured in WM varied from rostral to caudal as did mean translational motion, likely reflecting respiratory motion effect. Given the considerable sensitivity of DTI measurements to motion artifact, we believe outlier detection is indispensable in spinal cord diffusion imaging. We also recommend using a mixed-effects model to account for systematic measurement bias depending on cord segment.
Directional diffusivity; Outlier rejection; Non-negative eigenvalue priors; Reduced FOV; Cardiac gating; Cervical spinal cord; Lateral corticospinal tract; Posterior column; Diffusion tensor imaging; Reproducibility
Cervical spine injuries represent a minority of injury cases in motor vehicles accidents but are a real threat to a patient's life. In the wide range of cervical spine injuries, odontoid (dens) fractures represent the most common findings. These fractures are more usually found in the elderly population due to the changes associated with age. Neurological deficit is not frequently found in these injuries. The following is a case presentation of a chronic odontoid fracture with neurological deficit in a young man that was discovered 23 years after he sustained a motor vehicle accident.
The projectional nature of radiogram limits its amount of information about the instrumented spine. MRI and CT imaging can be more helpful, using cross-sectional view. However, the presence of metal-related artifacts at both conventional CT and MRI imaging can obscure relevant anatomy and disease. We reviewed the literature about overcoming artifacts from metallic orthopaedic implants at high-field strength MRI imaging and multi-detector CT. The evolution of multichannel CT has made available new techniques that can help minimizing the severe beam-hardening artifacts. The presence of artifacts at CT from metal hardware is related to image reconstruction algorithm (filter), tube current (in mA), X-ray kilovolt peak, pitch, hardware composition, geometry (shape), and location. MRI imaging has been used safely in patients with orthopaedic metallic implants because most of these implants do not have ferromagnetic properties and have been fixed into position. However, on MRI imaging metallic implants may produce geometric distortion, the so-called susceptibility artifact. In conclusion, although 140 kV and high milliamperage second exposures are recommended for imaging patients with hardware, caution should always be exercised, particularly in children, young adults, and patients undergoing multiple examinations. MRI artifacts can be minimized by positioning optimally and correctly the examined anatomy part with metallic implants in the magnet and by choosing fast spin-echo sequences, and in some cases also STIR sequences, with an anterior to posterior frequency-encoding direction and the smallest voxel size.
CT; MRI; Artifacts
Traumatic cervical spinal cord injury with subaxial fracture and dislocation not only indicates a highly unstable spine but can also induce life-threatening complications. This makes first aid critically important before any definitive operative procedure is undertaken. The present study analyzes the various first aid measures and operative procedures for such injury.
Materials and Methods:
Two hundred and ninety-five patients suffered from cervical spinal cord injury with fracture and dislocation. The average period between injury and admission was 4.5 days (range 5 h-12 weeks). The injury includes burst fractures (n = 90), compression fractures with herniated discs (n = 50), fractures and dislocation (n = 88) and pure dislocation (n = 36). Other injuries including developmental spinal canal stenosis and/or multi-segment spinal cord compression associated with trauma (n = 12), lamina fractures compressing the spinal cord (n = 6), ligament injuries (n = 7) and hematoma (n = 6) were observed in the present study. The injury level was C4 (n = 17), C5 (n = 29), C6 (n = 39), C7 (n = 35), C4-5 (n = 38), C5-6 (n = 58), C6-7 (n = 49), C4-6 (n = 16) and C5-7 (n = 14). According to the Frankel grading system, grade A was observed in 20 cases, grade B in 91, grade C in 124 and grade D in 60. One hundred and eighteen (40%) patients had a high fever and difficulty in breathing on presentation. First aid measures included early reduction and immobilization of the injured cervical spine, controlling the temperature, breathing support, and administration of high-dose methylprednisolone within eight hours of the injury (n = 12) and administration of dehydration and neurotrophy medicine. Oxygen support was given and tracheotomy was performed for patients with serious difficulty in breathing. Measures were taken to prevent bedsores and infections of the respiratory and urological systems. Two hundred and thirty six patients were treated with anterior decompression, 31 patients were treated by posterior approach surgery and combined anterior and posterior approach surgery was performed in a single sitting on 28 patients.
All patients were followed for 0.5-18 years (mean 11.8 years). At least one Frankel grade improvement was observed in 178 (60.3%) patients. In the anterior surgery group, the best results were observed in the cases with slight compressive fracture with disc herniation (44/50 patients, 88.0%). In the posterior surgery group, one Frankel grade improvement was observed in the cases with developmental spinal canal stenosis with trauma, lamina fractures, ligament injuries and hematoma (27/31, 87.1%). Most of the patients in the Frankel D group recovered normal neurological function after surgery. The majority of the patients with Frankel C neurological deficit (102/124) had the ability to walk postoperatively, while most of the seriously injured patients (Frankel A and B) had no improvement in their neurological function. Radiolographic fusion of the operated segments occurred in most patients within three months. Loss of intervertebral height and cervical physiological curvature was observed to varying degrees in 30.1% (71/236) of the cases in the anterior surgery group.
First aid measures of early closed reduction or realignment and immobilization of the cervical spine, breathing support and high-dose methylprednisolone were most important in the treatment for traumatic spinal cord injury. Surgery should be performed as soon as the indications of spinal injury appear. The choice of the approach—anterior, posterior or both, should be based on the type of the injury and the surgeon's experience. Any complications should be actively prevented and treated.
Cervical spine; first aid; spinal cord injury; surgical treatment
C1 fracture accounts for 2% of all spinal column injuries and 10% of cervical spine fractures, and is most frequently caused by motor vehicle accidents and falls. We present a rare case of C1 anterior arch fracture following standard foramen magnum decompression for Chiari malformation type 1.
A 63-year-old man underwent standard foramen magnum decompression (suboccipital craniectomy and C1 laminectomy) under a diagnosis of Chiari malformation type 1 with syringomyelia in June 2009. The postoperative course was uneventful until the patient noticed progressive posterior cervical pain 5 months after the operation. Computed tomography of the upper cervical spine obtained 7 months after the operation revealed left C1 anterior arch fracture. The patient was referred to our hospital at the end of January 2010 and C1–C2 posterior fusion with C1 lateral mass screws and C2 laminar screws was carried out in March 2010. Complete pain relief was achieved immediately after the second operation, and the patient resumed his daily activities.
Anterior atlas fracture following foramen magnum decompression for Chiari malformation type 1 is very rare, but C1 laminectomy carries the risk of anterior arch fracture. Neurosurgeons should recognize that fracture of the atlas, which commonly results from an axial loading force, can occur in the postoperative period in patients with Chiari malformation.
Anterior atlas fracture; C1 laminectomy; C1–C2 posterior fusion; Chiari malformation type 1; foramen magnum decompression
Head-first sports-induced impacts cause cervical fractures and dislocations and spinal cord lesions. In previous biomechanical studies, researchers have vertically dropped human cadavers, head-neck specimens, or surrogate models in inverted postures.
To develop a cadaveric neck model to simulate horizontally aligned, head-first impacts with a straightened neck and to use the model to investigate biomechanical responses and failure mechanisms.
Descriptive laboratory study.
Biomechanics research laboratory.
Patients or Other Participants
Five human cadaveric cervical spine specimens.
The model consisted of the neck specimen mounted horizontally to a torso-equivalent mass on a sled and carrying a surrogate head. Head-first impacts were simulated at 4.1 m/s into a padded, deformable barrier.
Main Outcome Measure(s)
Time-history responses were determined for head and neck loads, accelerations, and motions. Average occurrence times of the compression force peaks at the impact barrier, occipital condyles, and neck were compared.
The first local compression force peaks at the impact barrier (3070.0 ± 168.0 N at 18.8 milliseconds), occipital condyles (2868.1 ± 732.4 N at 19.6 milliseconds), and neck (2884.6 ± 910.7 N at 25.0 milliseconds) occurred earlier than all global compression peaks, which reached 7531.6 N in the neck at 46.6 milliseconds (P < .001). Average peak head motions relative to the torso were 6.0 cm in compression, 2.4 cm in posterior shear, and 6.4° in flexion. Neck compression fractures included occipital condyle, atlas, odontoid, and subaxial comminuted burst and facet fractures.
Neck injuries due to excessive axial compression occurred within 20 milliseconds of impact and were caused by abrupt deceleration of the head and continued forward torso momentum before simultaneous rebound of the head and torso. Improved understanding of neck injury mechanisms during sports-induced impacts will increase clinical awareness and immediate care and ultimately lead to improved protective equipment, reducing the frequency and severity of neck injuries and their associated societal costs.
head-first impacts; cervical spine; injury mechanisms
A congenitally narrow cervical spinal canal has been established as an important risk factor for the development of cervical spondylotic myelopathy. However, few reports have described the mechanism underlying this risk. In this study, we investigate the relationship between cervical spinal canal narrowing and pathological changes in the cervical spine using positional magnetic resonance imaging (MRI). Two hundred and ninety-five symptomatic patients underwent cervical MRI in the weight-bearing position with dynamic motion (flexion, neutral, and extension) of the cervical spine. The sagittal cervical spinal canal diameter and cervical segmental angular motion were measured and calculated. Each segment was assessed for the extent of intervertebral disc degeneration and cervical cord compression. Based on the sagittal canal diameter, the subjects were classified into three groups: A, subjects with a congenitally narrow canal, diameter of less than 13 mm; B, subjects with a normal canal, diameter of 13–15 mm; C, subjects with a wide canal, diameter of more than 15 mm. When compared with Groups A and B, the disc degeneration grades at the C3-4, C5-6, and C6-7 segments and the cervical cord compression scores at the C3-4 and C5-6 segments showed significant differences. Additionally, when compare with Groups A and C, the disc degeneration grades at all segments, except C2-3, and the cervical cord compression scores at all segments, except C2-3, showed significant differences. With respect to the cervical kinematics, few differences in the kinematics were observed between Groups B and C, however, the kinematics in Group A was different with other two groups. In Group A, the segmental mobility at the C4-5 and C6-7 segments were significantly higher than those observed in Group B, and the segmental mobility at the C3-4 segment was significantly lower than that observed in Groups B or C. We demonstrated the unique pathological and kinematic traits of cervical spine that exist in a congenitally narrow canal. We hypothesize that kinematic trait associated with a congenitally narrow canal may greatly contribute to pathological changes in the cervical spine. Our results suggest that cervical spinal canal diameter of less than 13 mm may be associated with an increased risk for development of pathological changes in cervical intervertebral discs. Subsequently, the presence of a congenitally narrow canal can expose individuals to a greater risk of developing cervical spinal stenosis.
A congenitally narrow canal; Cervical spine; Intervertebral disc; Cervical spinal stenosis; Positional MRI
Diagnosis of cervical facet dislocation is difficult when relying on plain radiographs alone. This study evaluates the interobserver reliability of helical computed tomography (CT) in the assessment of cervical translational injuries, correlates the radiographic diagnosis with intraoperative observation, and examines the role of neurologic injury in the evaluation and diagnosis of these injuries.
Clinical histories and radiographic studies of 10 patients with cervical facet dislocations were presented to 25 surgeons. Participants classified cases as unilateral or bilateral facet dislocations after reviewing selected axial CT slices and sagittal reconstructions. Surgeons' interpretations were compared with intraoperative diagnosis. Participants interpreted the same radiographic studies with 3 different clinical scenarios: neurologically intact, incomplete, and complete spinal cord injury. Vertebral body translation from midsagittal CT was evaluated to confirm whether all unilateral facet dislocations had <25% translation.
Interrater κ coefficient showed moderate agreement between observers in classifying injuries as unilateral or bilateral (κ: 0.54–0.58), regardless of neurologic status. Percent agreement among observers varied from 50% to 100% for each individual case. Agreement was statistically higher for bilateral facet dislocation (85%) than for unilateral dislocations (78%), with 1 unilateral fracture showing nearly 50% translation on a midsagittal image.
The addition of helical CT to reconstruction enables spine surgeons to more reliably distinguish bilateral from unilateral cervical facet dislocations. Despite frequent occurrence of these injuries and presumed agreement on injury description, agreement may be improved by a more precise definition of facet dislocations and subluxations and thorough review of all imaging studies.
Spine, cervical; Facet dislocation; Imaging; Computed tomography; Trauma, spinal
Between 23 and 70% of occupants involved in frontal impacts sustain cervical spine injuries, many with neurological involvement. It has been hypothesized that cervical spinal cord compression and injury may explain the variable neurological profile described by frontal impact victims. The goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to quantify canal pinch diameter (CPD) narrowing during frontal impact and to evaluate the potential for cord compression. The biofidelic model and a sled apparatus were used to simulate frontal impacts at 4, 6, 8, and 10 g horizontal accelerations of the T1 vertebra. The CPD was measured in the intact specimen in the neutral posture (neutral posture CPD), under static sagittal pure moments of 1.5 Nm (pre-impact CPD), during dynamic frontal impact (dynamic impact CPD), and again under static pure moments following each impact (post-impact CPD). Frontal impact caused significant (P<0.05) dynamic CPD narrowing at C0-dens, C2-C3, and C6-C7. The narrowest dynamic CPD was observed at C0-dens during the 10 g impact and was 25.9% narrower than the corresponding neutral posture CPD. Interpretation of the present results indicate that the neurological symptomatology reported by frontal impact victims is most likely not due to cervical spinal cord compression. Cord compression due to residual spinal instability is also not likely.
Frontal impact; Injury mechanism; Spinal cord injury; Cervical spine; Spinal cord narrowing
The aim of this study was to assess the effectiveness and feasibility of anterior C3 corpectomy and fusion with screw-plate fixation of C2–4 for the treatment of Hangman’s fracture in which spinal cord compression comes from the posterosuperior part of C3 vertebral body and the intervertebral disc injury at the C2–3 level.
From August 2000 to December 2005, 11 patients (eight males and three females) with traumatic spondylolisthesis of the axis underwent the above surgery. Neurological status was evaluated by the Japanese Orthopaedic Association Score (JOA score). The fusion of the graft, healing of the fracture, and range of motion of the whole cervical spine were examined according to X-ray imaging.
No patient received blood transfusion. There was no deterioration of the neurological function in any case postoperatively. The mean JOA score was significantly improved from 9.1 ± 2.3 preoperatively to 14.8 ± 1.2 at the 12-month postoperative visit. All patients were relieved of axial pain. Imaging evaluation confirmed a high fusion rate and healing rate in all patients. No patient complained of limited mobility of the cervical spine in flexion, extension and rotation. No graft or plate-related complication was observed in any patients during the whole follow-up period. The only postoperative complication was trouble in swallowing liquids in two cases which resolved three months after surgery without any treatment.
Anterior C3 corpectomy and fusion may prove to be safe and applicable for the treatment of complex Hangman’s fractures.
Nearly all children with MPS IVA develop skeletal deformities affecting the spine. At the atlanto-axial spine, odontoid hypoplasia occurs. GAG deposition around the dens, leads to peri-odontoid infiltration. Transverse/alar ligament incompetence causes instability. Atlanto-axial instability is associated with cord compression and myelopathy, leading to major morbidity and mortality. Intervention is often required. Does the presence of widened bullet shaped vertebra in platyspondily encroach on the spinal canal and cause spinal stenosis in MPS IVA? So far, there have been no standardised morphometric measurements of the paediatric MPS IVA cervical spine to evaluate whether there is pre-existing spinal stenosis predisposing to compressive myelopathy or whether this is purely an acquired process secondary to instability and compression. This study provides the first radiological quantitative analysis of the cervical spine and spinal cord in a series of affected children. MRI morphometry indicates that the MPS IVA spine is narrower at C1–2 level giving an inverted funnel shape. There is no evidence of a reduction in the Torg ratio (canal-body ratio) in the cervical spine. The spinal canal does not exceed 11 mm at any level, significantly smaller than normal historical cohorts (14 mm). The sagittal diameter and axial surface area of both spinal canal and cord are reduced. C1–2 level cord compression was evident in the canal-cord ratio but the Torg ratio was not predictive of cord compression. In MPS IVA the reduction in the space available for the cord (SAC) is multifactorial rather than due to congenital spinal stenosis.
This report presents a case of non-traumatic posterior atlanto-occipital dislocation. A 36-year-old female was referred with a history of numbness of the extremities, vertigo and neck pain for 1 year. The patient had no history of trauma. The axial rotation of range of motion of the cervical spine was severely restricted. A lateral cervical radiograph in the neutral position demonstrated a posterior atlanto-occipital dislocation. A coronal view on a computed tomography (CT) reconstruction image showed a loss of angle of the bilateral atlanto-occipital joint, and a sagittal reconstruction view of CT images also demonstrated flatness of atlanto-occipital joint. Instrumented occipito-cervical fusion was performed after reduction. A lateral cervical radiograph in the neutral position 1 year after surgery showed the reduction of atlanto-occipital joint, moreover, it was maintained even in an extended position. The patient had neurologic improvement after surgery. Flatness of the bilateral atlanto-occipital joint may have induced this instability. Occipital–cervical fusion was chosen in the present case since the patient showed restricted axial rotation of the neck before surgery. The surgery improved the preoperative symptoms including the function of cervical spine evaluated by JOACMEQ.
Atlanto-occipital joint; Subluxation