Computed tomographic and magnetic resonance imaging of chronic odontoid fractures

STUDY DESIGN: The analysis of the imaging characteristics found in chronic odontoid fractures. OBJECTIVES: To determine the efficacy of computed tomography and magnetic resonance imaging in diagnosing a chronic odontoid fracture. SUMMARY OF BACKGROUND DATA: Radiographic examination of the cervical spine is intrinsic to the evaluation of all patients with blunt trauma. Injury to the craniocervical junction constitutes 19-25% of all cervical spine fractures. At the authors' trauma center computed tomography is routinely used instead of the open-mouth odontoid radiograph to facilitate cervical spine evaluation. This practice has increased the detection of fractures that are unrecognized in plain radiography, and has, at the same time, raised questions about the age and significance of these fractures. METHODS: Radiography, computed tomography, and magnetic resonance imaging studies were performed on three patients who came to the emergency department with odontoid fractures. Two patients had a history of severe trauma, and one had a history inconsistent with an acute odontoid fracture. One patient also had a technetium Tc 99m methylene dihydroxyphosphonate bone scan. The studies were obtained to determine the age of the fractures. RESULTS: All three patients were determined to have chronic odontoid fractures. This diagnosis was facilitated by the use of computed tomographic and magnetic resonance imaging. Computed tomography showed increased sclerosis in the proximal fracture fragment in all cases and well-corticated fracture edges in one patient. Magnetic resonance images showed normal bone marrow or bone sclerosis in the odontoid process. Soft tissue edema was absent. A bone scan was not useful in resolving this issue. CONCLUSION: Computed tomography and magnetic resonance imaging can be useful in determining the chronicity of an odontoid fracture.     

Analysis of the IgG autoantibody repertoire in endocrine ophthalmopathy using the MegaBlot technique

The cervical spine is frequently involved in rheumatoid arthritis and yet there exists no consensus on the need to screen for cervical spine subluxations preoperatively. We reviewed retrospectively 77 patients who underwent 132 operations under general or regional anaesthesia over a 44-month period. We found that while the majority of patients had received preoperative X-ray screening for cervical spine instability, a third of the X-ray examinations done had been inadequate. Many anaesthetists did not repeat cervical spine X-rays if there were previously performed views available. We showed that a complete X-ray examination of the cervical spine should include flexion and extension stress views in addition to frontal views of the odontoid and entire cervical spine. Anterior atlantoaxial subluxation was the most common subluxation encountered in our study population. The detection of cervical spine instability was found to significantly affect anaesthetic management, favouring techniques that avoided unprotected manipulations of the neck under anaesthesia.     

Three-dimensional motion of the upper cervical spine in rheumatoid arthritis

Rheumatoid arthritis frequently contributes to instability of the upper cervical spine. Rotational instability of the upper cervical spine was evaluated in rheumatoid arthritis patients using biplanar x-ray photogrammetry. Three-dimensional cervical motion and the instantaneous axis of rotation of the atlas relative to the axis were evaluated in normal and rheumatoid arthritis patients during axial rotation in the horizontal plane. Anterior atlantoaxial subluxation did not increase during axial head rotation in either the atlantoaxial subluxation or the vertical subluxation groups, while the instantaneous axes of rotation were distributed posteriorly in the dens in the RA-normal group, but were widely scattered in the atlantoaxial subluxation group.     

Rheumatoid arthritis and vertebral artery occlusion: a case report with angiographic and magnetic resonance demonstration

A 40-year-old woman with rheumatoid arthritis (RA) who presented with vertigo and nausea, was found to have left vertebral artery occlusion on angiography. There was minimal atlantoaxial subluxation and no odontoid herniation. Magnetic resonance imaging (MRI) was suggestive of a left vertebral artery dissection. This is the first report of MRI of vertebral artery occlusion in RA. It will be important to accumulate MR images of this complication in future cases.     

Carcinogenic aspect of xenobiotic molecules belonging to the peroxisome proliferator family

STUDY DESIGN: Cervical motion patterns were analyzed in a normal population and in patients with cervical instability by using cineradiography. OBJECTIVES: To determine normal and pathologic motion patterns in the cervical spine through an in vivo continuous motion analysis. SUMMARY OF BACKGROUND DATA: Cineradiographic techniques have been used in a limited number of studies to quantify spinal motion. There is a paucity of information regarding dynamic motion patterns in normal and pathologic cervical spines. METHODS: Ten healthy subjects and 12 patients with unstable cervical spines (C1-C2 subluxation caused by rheumatoid arthritis, n = 10; instability below C2, n = 2) were studied. Cervical motion during flexion from the maximum extension position was recorded using cineradiography. Cervical segmental motions (C1-C2 to C5-C6) were continuously measured through quantifying cineradiographic images projected on a digitizer. RESULTS: Normal cervical spines showed a well-regulated stepwise motion pattern that initiated at C1-C2 and transmitted to the lower segments with time lags. Pathologic spines showed a different order of onset of segmental motion. In patients with rheumatoid arthritis who had atlantoaxial subluxation, C1-C2 motion initiated significantly earlier than C2-C3 motion. In patients with segmental instability below C2, motion in the unstable segments preceded that in the upper intact segments. CONCLUSIONS: Different motion patterns were observed between normal and pathologic cervical spines. Cineradiographic motion analysis is a valuable adjunctive technique, especially in diagnosis or evaluation of conditions that cannot be identified through conventional radiographic examination.     

Work capacity of the upper limbs after mastectomy

A 59-year-old man presented with neck pain and limb numbness. He also had bilateral symmetrical joint deformities of his hands and wrists. Cervical spine radiographs showed C 1/2 instability and features of rheumatoid arthritis. Magnetic resonance imaging demonstrated erosion ofthe odontoid peg by pannus. C 1/2 surgical fusion was performed. The role of imaging in cervical spine involvement by rheumatoid arthritis is reviewed.     

Characteristics of ANP-binding sites in the adrenal capsules of term-pregnant rats

Magnetic resonance imaging (MRI) of the cervical spine was performed on 20 patients (mean age 10 years) with a preliminary diagnosis of juvenile rheumatoid arthritis (JRA). In all patients conventional x-rays of the cervical spine were obtained, and the relationship between clinical status and MRI findings were evaluated. Two patients with clinical manifestations, including neck pain and diminished range of motion, exhibited significant pathologic features on radiogram and MRI, the latter providing more detailed information. Among 18 patients who had no complaints about their cervical spines, 3 patients (65%) had either soft tissue involvement, pannus formation or erosions on the surface of atlantoaxial joints; only four patients (20%) had erosions on plain x-ray views. Since the early diagnostic ability of MRI in JRA allows early therapeutic intervention, every patient with a probable diagnosis of JRA would benefit from MRI.     

Counterflow centrifugal elutriation: present and future

Only single cases with rheumatoid arthritis of the thoracic spine with vertebral subluxation have been reported to date. In a review of 100 patients with severe rheumatoid arthritis who had undergone occipitocervical fusion, arthritis of the upper thoracic spine with subluxation was discovered on conventional radiographs in four patients. Two additional patients were found elsewhere. Magnetic resonance imaging (MRI) was performed in three of the patients, confirming the diagnosis of subluxation of the upper thoracic vertebrae. In addition, MRI revealed encroachment on the anterior subarachnoid space and compression of the spinal cord.     

The radiographic and imaging characteristics of porous tantalum implants within the human cervical spine

STUDY DESIGN: Seven cadaveric cervical spines were implanted with a porous tantalum spacer and a titanium alloy spacer, and their radiographic and imaging characteristics were evaluated. OBJECTIVE: To determine the radiographic characteristics of porous tantalum and titanium implants used as spacers in the cervical spine. SUMMARY OF BACKGROUND DATA: Anterior decompressive surgery of the disc space or the vertebral body creates a defect that frequently is repaired with autologous bone grafts to promote spinal fusion. Donor site morbidity, insufficient donor material, and additional surgical time have spurred the development of biomaterials to replace or supplement existing spinal reconstruction techniques. Although the promotion of a solid bony fusion is critical, the implanted biomaterial should be compatible with modern imaging techniques, should allow visualization of the spinal canal and neural foramina, and should permit radiographic assessment of bony ingrowth. METHODS: Cadaveric spines containing the implants were imaged with plain radiography, computerized tomography, and magnetic resonance imaging. The image distortion produced by the implants was determined qualitatively and quantitatively. RESULTS: The tantalum and titanium spacers were opaque on plain radiographic films. On computed tomographic scans, more streak artifact was associated with the tantalum implants than with the titanium. On magnetic resonance imaging, the porous tantalum implant demonstrated less artifact than did the titanium spacer on T1- and T2-weighted spin echo and on T2*-weighted gradient-echo magnetic resonance images. Overall, the tantalum implant produced less artifact on magnetic resonance imaging than did the titanium spacer and therefore allowed for better visualization of the surrounding bony and neural structures. CONCLUSION: The material properties of titanium and porous tantalum cervical interbody implants contribute to their differential appearance in different imaging methods. The titanium implant appears to image best with computed tomography, whereas the porous tantalum implant produces less artifact than does the titanium implant on several magnetic resonance imaging sequences.     

Surgery in the degenerative cervical spine

Degenerative changes of the cervical spine include changes of the bony and discoligamentous structures that can create mechanical alterations of the anatomy. Compressive syndromes and deformation or instability represent basic indications for surgery. In the upper cervical spine, osteoarthritis of the C1-C2 facet manifests with suboccipital pain syndrome caused by generally unilateral degenerative changes of the atlantoaxial facet. Fixation and atlantoaxial fusion represent the treatment of choice. In rare instances the presence of os odontoideum is responsible for atlantoaxial instability. Narrowing of the lateral recess in the subaxial spine produces radicular symptoms. The clinical symptoms should be supported with imaging methods such as computed tomography or magnetic resonance imaging. Selective decompression produces satisfactory results. Spondylotic cervical myelopathy requires the addition of neurophysiologic investigations. Posterior decompression with laminoplasty or anterior decompression procedures with corpectomy of the involved segments represent therapeutic options with comparable results. In the presence of axial neck pain, the exact location of the painful segment challenges clinicians and radiologists. Only in cases in which the clinical findings correlate with the radiologic changes should surgical fusion be considered as a last therapeutic means to resolve the painful condition.     

Biomechanical aspects of the subarachnoid space and cervical cord in healthy individuals examined with kinematic magnetic resonance imaging

STUDY DESIGN: In vivo flexion-extension magnetic resonance imaging studies of the cervical spine were performed inside a positioning device. OBJECTIVE: To determine the functional changes of the cervical cord and the subarachnoid space that occur during flexion and extension of the cervical spine in healthy individuals. SUMMARY OF BACKGROUND DATA: As an addition to static magnetic resonance imaging examinations, kinematic magnetic resonance imaging studies of the cervical spine were performed to obtain detailed information about functional aspects of the cervical cord and the subarachnoid space. The results were compared with published data of functional flexion-extension myelograms of the cervical spine. METHODS: The cervical spines of 40 healthy individuals were examined in a whole-body magnetic resonance scanner from 50 degrees of flexion to 30 degrees of extension, using a positioning device. At nine different angle positions, sagittal T1-weighted spin-echo sequences were obtained. The images were analyzed with respect to the segmental motion, the diameter of the subarachnoid space, and the diameter of the cervical cord. RESULTS: The segmental motion between flexion and extension was 11 degrees at C2-C3, 12 degrees at C3-C4, 15 degrees at C4-C5, 19 degrees at C5-C6, and 20 degrees at C6-C7. At flexion, a narrowing of the ventral subarachnoid space of up to 43% and a widening of the dorsal subarachnoid space of up to 89% (compared with the neutral position, 0 degrees) were observed. At extension, an increase in the diameter of the ventral subarachnoid space of up to 9% was observed, whereas the dorsal subarachnoid space was reduced to 17%. At flexion, there was a reduction in the sagittal diameter of the cervical cord of up to 14%, and, at extension, there was an increase of up to 15%, compared with the neutral position (0 degrees; these values varied depending on the cervical segment. Statistically significant differences (P < 0.05) were found between flexion and extension in the diameter of the ventral and dorsal subarachnoid space and in the diameter of the cervical cord. CONCLUSIONS: Compared with the results of previous studies using functional cervical myelograms, kinematic magnetic resonance imaging provides additional noninvasive data concerning the physiologic changes of the cervical subarachnoid space and the cervical cord during flexion and extension in healthy individuals.     

The cervical spine in the skeletal dysplasias and associated disorders

The cervical spine is an especially important area, not only for the diagnosis of the skeletal dysplasias, but also for the management of the patient. By the "cervical spine" I refer not only to the vertebral bodies and posterior elements of this region, but also to the neural elements contained within, especially the cervical cord. The spine is supported by a group of ligaments both anteriorly and posteriorly, with special fixation of the odontoid and C2 by a ligament which normally affixes it firmly to C1. Multiple things may go wrong with the development of the cervical spine. There may be abnormal development of the "vertebrae" in this region, ranging from hypoplasia to developmental failure and/or abnormal ossification of the cervical vertebrae; associated or unassociated odontoid hypoplasia; poor ligamental fixation of C2 resulting in C1-2 subluxation; abnormal development of the posterior processes; abnormal ligamental development or laxity with abnormal cervical kyphosis or lordosis; and, in the case of more fragile/brittle bone development (osteoporosis or increased bone density), fractures can lead to cervical spine problems. The skeletal dysplasias that involve cervical spine problems constitute about 35 of the 150 well-described disorders. These include certain families of disorders like the type II collagenopathies, as well as many individual disorders. It is very important for the clinician to be able to pilot patients through the various appropriate imaging modalities - conventional radiographs of the cervical spine; lateral flexion/extension views; CT; MRI - so that proper management and therapy will result.     

Radiographic evaluation of cervical spine trauma. Procedures to avoid catastrophe

A cervical spine series that includes three views (ie, lateral, open-mouth odontoid, and anteroposterior) is usually adequate to exclude unstable injuries that have the potential for producing spinal cord injury. The films should be of the highest quality and need to be carefully and systematically viewed. Knowledge of cervical spine anatomy and of common types of injuries (including their mechanisms) is essential for accurate interpretation. Conventional tomography, computed tomography, and flexion and extension lateral views may be helpful when findings on the three-view series are equivocal. In patients with neurologic deficits, further radiographic evaluation is also warranted.     

Odontoid process and C1-C2 corrective osteotomy through a posterior approach: technical case report

OBJECTIVE AND IMPORTANCE: To demonstrate a new posterior approach to the anterior elements of the atlas and the axis including the odontoid process. CLINICAL PRESENTATION: A 36-year-old woman presented with ankylosing spondylitis and severe flexion deformity of the cervical spine. She had sustained a trauma 5 years previously, causing the inability to look forward or to open the jaw adequately. An examination demonstrated fixed flexion and rotation of the cervical spine, with no neurological deficit. Radiologically, there was fusion of C1, C2, and the clivus. TECHNIQUE: The upper cervical vertebrae were exposed via a midline posterior incision, the posterior arch of C1 was excised, and the vertebral arteries were mobilized. A wedge osteotomy was performed through the lateral masses of C1 and subsequently through the odontoid. The head was repositioned, and C1-C2 lateral mass screws and a Ransford loop were inserted. CONCLUSION: It is possible to gain sufficient surgical access to the odontoid process via a posterior approach. The technique described is of benefit when the alternative anterior approaches to the upper cervical spine are technically difficult or impossible.     

The radiological investigation of lumbar spondylolysis

Lumbar spondylolysis represents a stress fracture of the pars interarticularis and occurs most commonly at the L5 level. Pars defects can be imaged with plain radiography, bone scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI). Plain radiographic projections of particular value include the coned lateral view of the lumbosacral junction, which displays the majority of defects, and the anteroposterior view with 30 degrees cranial angulation. The value of oblique radiography is unproven. Planar bone scintigraphy (PBS) is more sensitive than radiography and single photon emission computed tomography (SPECT) more sensitive and specific than PBS. Both these techniques, however, are less specific than radiography and CT. CT, when performed with a reverse gantry angle and thin sections, is the investigation of choice for identifying radiographically occult lyses. Conventional lumbar spine MRI techniques are valuable for demonstrating normality of the pars, but may be associated with a high false positive rate for the diagnosis of pars defects.     

Anesthesia induction for laryngeal mask insertion--comparison of propofol with midazolam and propofol with thiopental

STUDY DESIGN: Radiographs and charts of 61 patients sustaining cervical spine trauma were studied prospectively to determine the incidence of vertebral artery injuries and possible correlative factors. Statistical analysis was conducted using chi-square testing of a two-way classification system. OBJECTIVES: To elucidate the incidence of vertebral artery injuries associated with cervical spine trauma, and to determine the value of various factors in predicting the existence of a vertebral artery injury. SUMMARY OF BACKGROUND DATA: During a 7-month period, 61 patients (41 male patients, 20 female; average age, 40.3 years) with cervical spine trauma were studied. METHODS: All patients admitted to the authors' hospital with cervical spine injuries underwent magnetic resonance imaging and magnetic resonance angiography of their cervical spine. All magnetic resonance angiographies were examined for vertebral artery injury. Data on demographics and the injury were recorded. RESULTS: Complete disruption of blood flow through the vertebral artery was demonstrated by magnetic resonance angiography in 12 of the 61 patients (19.7%). Ten of the 12 patients (83%) had either flexion distraction or flexion compression injuries. Age, sex, mechanism of injury, neurologic impairment, and associated injuries were not statistically significant in predicting the presence of a vertebral vessel occlusion. CONCLUSION: The findings in this study may support the need for vertebral vessel evaluation in selective patients, particularly those with flexion injuries and with neurologic symptoms consistent with vertebral artery insufficiency syndrome that do not correlate with the presenting bone and soft-tissue injuries.     

Diagnosis of bronchial rupture with MR imaging

Tracheobronchial rupture is a serious injury occurring in approximately 1.5% of cases of major chest trauma. This injury is associated with significant mortality and morbidity and may be difficult to recognize both clinically and radiologically. Radiologic signs are mostly nonspecific, with pneumothorax and pneumomediastinum being the most common. A high level of suspicion is required to make the diagnosis. Computed tomography (CT) can be helpful; however, it provides only indirect evidence for the diagnosis. This report describes a case of complete transection of the right main bronchus, suspected at plain radiography and CT and clearly shown on magnetic resonance (MR) images. MR imaging, with its multiplanar capabilities, can be helpful in defining the location and extent of injury and in diagnosing injury not suspected or clearly demonstrated with other imaging modalities.     

Pathologic features of spinal disorders in patients treated with long-term hemodialysis

STUDY DESIGN: Pathologic features of hemodialysis-associated spinal disorders were evaluated using preoperative radiographic images and histologic findings of the spinal lesions resected during surgery. OBJECTIVES: To investigate the pathology of hemodialysis-related spinal disorders and to determine the role of amyloidosis in the establishment of severe destruction of the spine. SUMMARY OF BACKGROUND DATA: The pathologic events leading to hemodialysis-associated spinal disorders are poorly understood. The distribution of amyloid deposits in the spine also has not been clarified. METHODS: Twenty patients with hemodialysis-associated spinal disorders were investigated regarding pathologic features of neural compression and spinal destruction. Preoperative radiographic images such as plain radiography, tomography, computed tomography, magnetic resonance imaging, and scintigraphy were assessed for the existence of an intracanal mass, hypertrophy of the ligamentum flavum, and destructive changes of the spinal components. Histologic examination also was conducted by light microscopy and scanning electron microscopy to determine the distribution pattern of amyloid deposits in the spinal components. RESULTS: Six patients with no destructive changes in the spine showed spinal canal stenosis. In the cervical spine, a main factor associated with spinal canal stenosis was the presence of intracanal amyloid deposits in three patients. In the lumbar spine, a main factor associated with spinal canal stenosis was hypertrophied ligamentum flavum in three patients. Destructive changes of the facet joints, intervertebral disc, and vertebral body were seen in the other 14 patients. Amyloid deposits were densely distributed at the enthesis of capsular fibers to the bone and in anular tears in the intervertebral discs. Vertebral end plates were destroyed by penetration of amyloid granulation into the vertebral body. Osteoclast activity in the destroyed vertebral bodies was enhanced, with no evidence of new bone formation. CONCLUSIONS: Amyloid deposits played an important role in the progression of spinal destruction and severe instability.     

Case report: imaging of Takayasu arteritis in the acute stage

We report a case of Takayasu arteritis (TA) in the acute stage. The case is unique in two points. First, the diagnosis of Takayasu arteritis was initially suspected from a subtle finding on plain radiography. Second, thickening of the aortic and pulmonary arterial walls was demonstrated by computed tomography and magnetic resonance imaging in the acute non-pulseless stage of the disease.