The second edition of Skeletal Imaging was initially intended to be merely an adaptation of the first edition. The authors are indebted to Debra and Catherine, as well as to all the people mentioned here.
Introduction
2 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Spinal stenosis with posterior abrasion of vertebral bodies and reduced spinal canal diameter Vertebral bodies may be flat or wedge-shaped Diaphyseal widening of long bones. Narrow thorax, champagne glass pelvis Spread and bowl metaphyses of long bones Diastrophic dysplasia Rare autosomal recessive dwarf dysplasia Short stature, progressive scoliosis, kyphosis Spondyloepiphyseal.
Hurler syndrome) Atlantoaxial instability may be present
Reduced height of vertebral bodies, pear-shaped vertebrae in childhood, kyphoscoliosis, accentuated kyphosis and lordosis, pectus carinatum, delayed ossification, hypoplasia of the odontoid with.
Morquio syndrome)
May be associated with intermittent joint swelling, pain and limitation of movement, muscle contractures, shortening of tendons and ligaments, growth disturbances in the affected limbs and other musculoskeletal abnormalities. Rare condition in which patients have radiological findings characteristic of more than one, and sometimes all, of the sclerosing dysplasias.
6 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Distal portion of femur, patella, humeral head, glenoid rim, elbow, or hip Fracture of cartilage only: chondral fracture Fracture of bone and cartilage: osteochondral fracture Shear, rotational, or tangential impact forces generated by abnormal joint motion can result in fracture two articular surfaces located Momentary, continuous, or repeated dislocations and subluxations can result in these injuries associated with painful joint effusions, locking, clicking, and limitation of motion; common intra-articular bodies; bodies can adhere to the synovium and eventually resorb Osteochondritis Dissecans Femoral condyles and talus are the most typical sites Less common sites: other tarsal bones, tibia, humeral head, glenoid cavity, acetabulum, and elbow (capitulum) Palpation of the patella is rarely. Fragmentation and possible separation of part of the articular surface Most common onset in adolescence, but occurs from childhood to middle age Male > female Symptoms and signs usually begin in patients between the ages of 15 and 20; painful or painless joint effusion, joint locking, clicking, and limitation of motion Significant history of trauma in 50% of cases MR arthrography and CT arthrography are the most useful imaging techniques Avulsion injuries Avulsion fracture Tibial tubercle , olecranon, pelvis, thighs, tibial femurs. , spinous process Bone fragment is pulled from the parent bone by a tendon, ligament, or part of the joint capsule Improper fracture healing Delayed union Scaphoid and improperly immobilized fracture sites. odontoid process (os odontoideum), or any improperly immobilized site Also occurs in neurophy bromatosis and fi brous dysplasia.
8 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Humerus fractures in infants and femur fractures in crawling children should give rise to suspicion of abuse Diagnostic imaging. Fractures in various stages of healing, subperiosteal bleeding with periostitis, metaphyseal corner fractures, physical injuries and transverse diaphyseal or metaphyseal fractures.
10 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Articular degeneration in the absence of any obvious underlying abnormality Accompanying aging Clinical findings Variable, depending on site of involvement Periarticular bone enlargement; eg Heberden nodes Pain and tenderness variable Joint stiffness and reduced mobility Joint crepitus Occasional instability Subluxation and deformity. Articular degeneration that is caused by changes from a pre-existing disorder; some of these are as follows: Previous septic arthritis or inflammatory arthritis, slipped epiphysis, developmental dysplasia of the hip, fracture or dislocation, obesity, Legg-Calvé-Perthes disease, osteonecrosis, acromegaly, ochronosis, and occupational or athletic injury. occurs with crystal deposition diseases, synovial inflammatory processes and other articular diseases Clinical findings Same as in primary osteoarthritis; findings may coexist with or be obscured by those of the primary disorder.
12 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Bilateral symmetrical polyarticular synovial inflammatory process Five to 15 times more common than ankylosing spondylitis Clinical findings Acute or chronic episodes of painful joint swelling Prodromal symptoms: fatigue, anorexia, weight loss, malaise, muscle pain and stiffness Capsular and ligament laxity Muscle contraction and spasm Bursitis, tendinitis, and tenosynovitis Diagnostic criteria* 1. Morning stiffness in and around the joints lasting at least 1 hour before maximum improvement 2. Soft tissue swelling (arthritis) of three or more joint areas noted by the physician 3. Swelling (arthritis) ) proximal interphalangeal, metacarpophalangeal, or wrist joints 4. Symmetrical swelling (arthritis) 5. Rheumatoid nodules 6. Rheumatoid factor presence 7. X-ray erosions or periarticular osteopenia or both in the joints of the hand or wrist or both Rheumatoid arthritis is defined by the presence of four or more criteria ; criteria 1 through 4 must be present for at least 6 weeks. Other clinical findings Variable, depending on the disorder Subcutaneous nodules Acute joint swelling, pain and erythema Systemic manifestations: Vasculitis Hepatosplenomegaly Iridocyclitis Soft tissue swelling Periarticular osteoporosis with luminous metaphyseal bands Diffuse joint space loss (late detection) Erosions (late detection) Periostitis Growth disturbance Apophyseal ankylosis of the joint Extraaxial ankylosis of the joint Atlantoaxial instability Bone proliferation and periostitis Compression fractures of the epiphysis Cont.
14 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Laboratory findings HLA-B27 antigen present in as many as 75% of patients Leukocytosis Anemia Elevated erythrocyte sedimentation rate Imaging findings Axial skeleton: Paravertebral ossification (non-marginal parasyndesmophytes) Unilateral or bilateral asymmetric sacroiliitis Atlantoaxial instability Extraaxial skeleton: soft tissues cavity: periarticular or involving the entire finger (finger sausages) Absence of osteoporosis Diffuse loss of joint space New bone formation: whiskers, enthesopathy Enteropathic arthropathy Variable, depending on the underlying disease. Laboratory findings The HLA-B27 antigen is present in 90% of patients with ulcerative colitis and Crohn's disease who develop spondylitis or sacroiliitis. Imaging findings Spondylitis and sacroileitis identical to those of ankylosing spondylitis. Occasional Peripheral Joint Abnormalities Continued.
16 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Laboratory findings Anemia (70%-80% of patients) Leukopenia Plasma protein abnormalities False-positive serologic test for syphilis Formation of LE cells and other antinuclear factors Autoagglutination of red blood cells Symmetrical, deforming imaging findings Nonerosive arthropathy Acrosclerosis and subchondrosis . (rare) Resorption of phalangeal bundle Osteonecrosis: occurs in patients regardless of whether they have received corticosteroid therapy; possibly caused by vasculitis; Most common hip site Tendon weakening and rupture Insufficiency fracture Osteomyelitis and septic arthritis Mixed connective tissue disease20-50Female > male Hand Hand Foot. Overlap syndromes and mixed connective tissue diseases include combinations of rheumatoid arthritis, dermatomyositis, scleroderma, and systemic lupus erythematosus Clinical findings: Variable, depending on the predominant connective tissue disease involved.
18 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Laboratory findings Hyperuricemia Monosodium urate crystals in synovial effusion aspirate Imaging findings Most commonly present with chronic gouty arthropathy Extra-articular erosions with drooping edges of the cortex Intra-articular erosions Tophi (soft tissue deposition of crystal-absent nodules repetitious of urate osteoporosis ) Bony apposition Intraosseous calcification Predilection for hemochromatosis of the first metatarsophalangeal joint40-60 Male : female, 10 : 1 to 20 : 1. Rare progressive disorder involving joint damage from excessive iron deposition, classified into primary fiscal forms and secondary: pigmentation, liver cirrhosis and diabetes mellitus Joint pain, stiffness and swelling; usually bilateral.
20 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Extensive periarticular ossification of soft tissues occurs in up to 53% of paraplegic and quadriplegic patients after brain and spinal cord injury - as a result of burns, mechanical trauma and venous stasis. Clinical findings Some patients have no symptoms other than their own. The primary neurological disorder itself Others have pain, swelling, limited joint or synovial movement. Monoarticular proliferative synovial disorder of unknown cause 50% of patients have a history of trauma The extraarticular form is called giant cell tumor of the tendon sheath and is most commonly seen in the hand and foot. Slowly progressive joint pain, swelling, warmth, tenderness, and stiffness Aspiration: acute or chronic hemorrhage.
22 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
24 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Central chondrosarcoma Elongated, ill-defined lesions May have soft tissue mass Multi-lobed, osteolysis, cortical destruction, cortical thickening, periostitis, endosteal scalloping and calcification Peripheral chondrosarcoma Arising from pre-existing osteochondroma or, rarely, from the periosteal membrane in the form of juxtacortical chondrosarcoma Features of calcification Present in more than 60% of cases Well-organized calcification rings in low-grade chondrosarcomas Amorphous, punctate, scattered, or irregular calcification in high-grade chondrosarcomas Giant cell tumor (aggressive)30-503: 2Femur Tibia Radius Spine Humerus. Locally aggressive or malignant form of giant cell tumor is more common in men than in women. Five to 10% of giant cell tumors are malignant; radiographic appearance is an inaccurate guide to determining the malignancy of the lesion; biopsy is necessary The vast majority of malignant giant cell tumors arise after irradiation of benign giant cell tumors. Forty to 60% recurrence rate for all giant cell tumors. Tumor implantation can occur in distant locations, usually in the lungs, 2 to 5 years after surgical resection of the tumor. ; is more common in lesions at the distal end of the radius. Clinical findings Pain, local swelling, pathological fracture and limitation of movement in the adjacent joint. Pain is usually mild and lasts for several months, relieved by bed rest and worsened by activity.
26 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Skeletal abnormalities occur in 10%-25% of patients; more common in adults than in children More than 60% of patients have multiple sites of skeletal involvement. Clinical findings Lymphadenopathy, masses, hepatomegaly, splenomegaly, fever, night sweats, weight loss. No race predilection Clinical findings Localized pain and swelling, lymphadenopathy and splenomegaly Systemic signs and symptoms characteristically absent Skeletal involvement in up to 30% of patients with non-Hodgkin's lymphoma.
28 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Multiple enchondromas Tubular radiolucent areas extending from the physis into the metaphysis Shortening and deformity of affected bones Frequent calcification of the matrix Maffucci syndrome<101:1Tibia (50) Fibula (50) Hand, wrist Foot. Soft tissue hemangiomas: multiple phleboliths in the soft tissues Multiple central or eccentric radiolucent lesions containing variable amounts of calcification Shortening and deformity of affected bones Chondroblastoma10-252: 1Femur (33) Humerus (22) Tibia (18) Hands and feet (10) .
30 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Vascular channels in bones: cavernous, capillary or venous types. Single lesions predominate, but occasionally multiple lesions occur. Clinical Findings Usually discovered as an incidental finding. Occasional soft tissue swelling or pain, especially in the presence of a pathologic fracture. Rarely, spinal lesions may occur. complicated by spinal cord compression due to bone expansion, epidural tumor extension, epidural hemorrhage, or compression fracture. Radiolucent, slightly expansile intraosseous lesion. A radiating, reticulated, or reticulated trabecular pattern. Spinal lesions have a characteristic appearance of corduroy tissue: prominent vertical trabecular ridges within the radiolucent cancellous bone of the vertebral body; may extend into neural arch Occasional cortical thinning Rarely periostitis, soft tissue mass, or osteosclerosis Intracortical and periosteal hemangiomas (extremely rare) predominate in tibia and fibula Simple bone cyst5-252: 1 Humerus (56) Femur (27) Tibia (6) ) Fibula (5).
32 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Hand-Schüller-Christian disease: 10% of patients; most varied form with chronic proliferation of osseous lesions; associated with diabetes insipidus, exophthalmos and severe visceral involvement 3. Letterer-Siwe disease: 10% of patients; acute form with rapid spread, severe visceral involvement and poor clinical prognosis; usually affects children under 3 years of age.
34 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Interruption of orderly development and mineralization of the growth plate Causes Similar to those in osteomalacia Clinical findings Muscle tetany, weakness, delayed skeletal maturation, short stature, irritability, bone flexion deformities, rachitic rosary. Bone resorption: subperiosteal, subchondral, subligamentous, subtendinous, intracortical, endosteal urate and calcium pyrophosphate dihydrate (CPPD) crystal deposition osteosclerosis Rugger-jersey spine: horizontal bands of osteosclerosis adjacent to the superior and inferior surfaces of the vertebral body Brown tumor (osteoclastoma): solitary or multiple expansive osteolytic lesions containing fibrous tissue and giant cells; may resolve after treatment for hyperparathyroidism Tendon rupture Soft tissue and vascular calcification Renal osteodystrophy Uremic osteopathy in patients with chronic renal insufficiency Combination of osteomalacia or rickets and secondary hyperparathyroidism Clinical findings Most patients have chronic kidney disease and may be on dialysis treatment.
36 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Hypersecretion of growth hormone (somatotropin) causes acromegaly in adults and gigantism in children. Often associated with acidophilic or chromophobe adenomas of the anterior lobe of the pituitary gland. Clinical findings Enlarged acral parts, menstrual disorders, headaches, amenorrhea, increased basal metabolism, hyperhidrosis, skin pigmentation, weight gain, hypertrichosis, back pain, limb arthropathy, compression neuropathy, neuromuscular symptoms, Raynaud's phenomenon. See also: Ameen S, Staub L, Ulrich, et al: Harris lines of the tibia through the ages: a comparison of two populations, medieval and modern in Central Europe.
38 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Symptomatic painful crises begin during the second or third year of life and include anemia, fever, jaundice, nausea, vomiting, abdominal pain, and exhaustion. Severe form of anemia associated with hepatosplenomegaly and bone abnormalities Usually occurs in patients with.
40 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Thick and single layer of periosteal bone proliferation Areas of osteolysis and ill-defined areas of sclerosis Sequestrum and involucrum. Brodie abscess Subacute pyogenic osteomyelitis More common in children Predilection for distal tibial metaphysis Rarely extends to epiphysis.
42 CHAPTER 1 Introduction to Skeletal Disorders: General Concepts
Spine
NORMAL DEVELOPMENTAL ANATOMY
DEVELOPMENTAL ANOMALIES,
ANATOMIC VARIANTS, AND SOURCES OF DIAGNOSTIC ERROR
SKELETAL DYSPLASIAS AND OTHER CONGENITAL DISEASES
PHYSICAL INJURY
Ages of appearance and fusion of ossification centers in girls typically precede those of boys.
ARTICULAR DISORDERS
BONE TUMORS
METABOLIC DISEASES
INTERVERTEBRAL DISC ABNORMALITIES
CERVICAL SPINE SURGERY
VASCULAR DISORDERS
46 CHAPTER 2 Cervical Spine
The superior aspects of the vertebral bodies are rounded, the spinal canal remains proportionally wide, and the posterior margins of the vertebral bodies are scalloped. The anterior arch of the atlas appears to be displaced superiorly in relation to the tip of the odontoid.
48 CHAPTER 2 Cervical Spine
Incomplete development of bony structures results in a proportionally wide appearance of the spinal canal.
50 CHAPTER 2 Cervical Spine
Accessory ossicles9 2-8 A variety of small ossicles may be present in the atlas region. Usually without clinical significance. Posterior ponticulus6 2-9 Ossification of the posterior atlanto-occipital membrane present in 15% of normal individuals The arcuate foramen allows passage of the vertebral artery and C1 nerve.
52 CHAPTER 2 Cervical Spine
FIGURE 2-4 Atlanto-occipital assimilation (occipitalization).4 A-B, Lateral radiograph (A) and frontal conventional tomogram (B) show fusion of the occipital condyle with the lateral mass of C1 on the right side and to a lesser extent on the left. Lateral radiograph (C) shows assimilation of the atlas with the base of the occiput (right arrow), synostosis (block vertebrae) of C2-C3 (left arrow), and mild basilar impression.
54 CHAPTER 2 Cervical Spine
FIGURE 2-7 Agenesis of the anterior arch of C1.4-7 A, transaxial CT bone window through the occipito-atlanto-axial region of this 36-year-old woman reveals a midline radiolucency (arrow) representing failure of complete ossification of the anterior tubercle of the atlas. FIGURE 2–8 Accessory bone.9 Note the small ossicle located at the inferior aspect of the anterior arch of C1 (arrow).
56 CHAPTER 2 Cervical Spine
FIGURE 2–11 Asymmetric atlas.7 The atlas has developed asymmetrically, simulating a compression fracture of the left lateral mass. FIGURE 2–12 Simulated fracture produced by rotation.5,7 A, Lateral radiograph taken in extension shows an apparent fracture of the posterior arch of the atlas with displacement of the fragments (arrow).
58 CHAPTER 2 Cervical Spine
FIGURE 2–15 Os terminale of Bergmann.5,7 A, Observe the small circular ossification center in the triangular or V-shaped radiolucent depression (arrows). The os terminale of Bergmann represents a persistent, ununited secondary growth center at the apex of the odontoid in a patient older than 12 years.
60 CHAPTER 2 Cervical Spine
FIGURE 2–17 Posterior inclination of the odontoid.12 The odontoid is tilted posteriorly (arrows) in this patient with no history of trauma. The atlantodental gap, measured in the neutral, flexion or extension position, should not exceed 3 mm in adults and 5 mm in children.
62 CHAPTER 2 Cervical Spine
The posterior arch of C1 is fused with the C2 spinous process and lamina, and an anomalous foramen is present between the C1 and C2 segments, resembling an intervertebral foramen.
64 CHAPTER 2 Cervical Spine
FIGURE 2–22 C2 pseudosubluxation.16,17,135 Observe the anterior displacement of the C2 vertebral body (arrow) relative to that of C3 in this 5-year-old child. Excessive motion in the sagittal plane of the C2-C3 and C3-C4 motion segments, seen on flexion and extension radiographs in infants, is also a common finding attributed to normal ligamentous laxity.
66 CHAPTER 2 Cervical Spine
2-32 Developmental narrowing of the spinal canal is uncommon and may be seen as an isolated phenomenon or associated with achondroplasia. Combination of anomalies including spina bifi da occulta, neural arch defect (such as pedicle agenesis) and anterolisthesis of the vertebral body.
68 CHAPTER 2 Cervical Spine
FIGURE 2–27 Nuclear impressions.2,7 Lateral radiograph shows prominent, broad-based, curvilinear depressions of the superior and inferior vertebral endplates. FIGURE 2–28 Anomalous development of C6.7 The C6 vertebral body appears flat (open arrow), and the spinous process is thin and weakened (arrow).
70 CHAPTER 2 Cervical Spine
FIGURE 2–30 Articular process notch.22 Notching of the superior apophyseal articular surface of C7 (arrow) represents a normal variation that may simulate an erosion or a fracture.
72 CHAPTER 2 Cervical Spine
FIGURE 2–32 Developmental (congenital) spinal stenosis.6 Lateral cervical radiograph in this 18-year-old man who presented with upper extremity hyperesthesia shows narrowing of the of the spinal canal (double arrows). The sagittal dimension of the cervical spinal canal should never measure less than 12 mm, or less than 80% of the midvertebral body width.
74 CHAPTER 2 Cervical Spine
FIGURE 2–35 Persistent (ununited) secondary ossification centers.7 A, An aberrant auditory ossicle is present adjacent to the tip of the T1 transverse process and first rib (arrow). This probably represents failure of fusion of the secondary ossification center at the tip of the transverse process, a structure that usually fuses by the age of 25 years.
76 CHAPTER 2 Cervical Spine
FIGURE 2–37 Tracheal annular calcification.6 Prominent annular calcification of the tracheal cartilage is evident on a lateral radiograph of this 50-year-old woman. FIGURE 2–39 Cervical lymph node calcification.6,27 Lobular accumulations of calcification (A-B) are visible within the paraspinal soft tissues of the neck.
78 CHAPTER 2 Cervical Spine
FIGURE 2–41 Spondyloepiphyseal dysplasia congenita.30 This 5-year-old boy has platyspondyly, a hypoplastic odontoid process with atlantoaxial subluxation, instability, and craniocervical canal stenosis. FIGURE 2–42 Mucopolysaccharidosis: MPS IV (Morquio syndrome).31,32 A, Sagittal reformatted CT image of the upper cervical region of a young child reveals the age of the odontoid, an important cause of atlantoaxial instability in patients with MPS IV.
80 CHAPTER 2 Cervical Spine
Reprinted with permission from Stiell IG, Clement CM, McKnight D, et al: The Canadian C-spine rule versus the NEXUS low-risk criteria in trauma patients. Extension teardrop fracture (stable in flexion) Compression fracture of C1 (Jefferson burst fracture) Unilateral facet dislocation.
82 CHAPTER 2 Cervical Spine
Anterior arch fracture46,147 Usually stable Disruptive hyperextension Horizontal fracture seen on lateral radiograph produced by avulsion of the tubercle of the anterior arch by the superior oblique of the longus colli muscle and the anterior longitudinal ligament Often associated with fractures of C1 massontoid Isol arch and bone fractures fracture46,147Usually stable Axial compression or lateral hyperflexion Extremely rare injury Fracture of the medial aspect of the lateral mass may be due to avulsion of the transverse ligament Isolated transverse process fracture46,147Usually stableLateral hyperflexionExtremely rare Rare potential injury at C1 level Potential injuries to vertebry injuries. 47 ,48,147 Complex and poorly understood mechanism including combinations of extreme flexion, extension, rotation and shear. Most common axial fracture: 55% of C2 fractures; 7%-13% of all cervical spine injuries Up to 90% of affected patients are neurologically intact at the time of injury but may develop late-onset neurological deficit Fracture-dislocation may complicate odontoid fractures Anterior odontoid displacement from flexion forces Lateral odontoid displacement from lateral flexion or rotational forces Three types of odontoid fracture based on fracture location Type I2-49Stable Least common type: believed to be caused by alar ligament avulsion Unilateral oblique fracture through the apex of the odontoid above the transverse ligament Nonunion and displacement rare Type II2 -50Unstable Most common type Fracture occurs through the base of the odontoid at its junction with the C2 body; frequently disrupts blood supply Nonunion occurs in more than 25% of cases Displacement (more than 60% of cases) and angulation (more than 25%) increase the likelihood of nonunion Popular theory holds that os odontoideum actually represents a chronic nonunion type II odontoid fracture rather than a developmental anomaly Type III2-51StableHorizontal or oblique fracture line extends from the base of the odontoid into the cancellous bone of the vertebral body, typically out through the articular process of C2 into the C1-C2 articulation Anterior displacement occurs in 58% of cases and lateral inclination of the odontoid more than 5 degrees is present in about 66% of cases Union does not occur in less than 13% of cases Continued.
84 CHAPTER 2 Cervical Spine
FIGURE 2–44 Atlanto-occipital dislocation.38,39 This 28-year-old man was involved in a serious motor vehicle accident. FIGURE 2–45 Traumatic transverse ligament rupture The atlantodental space is widened (arrow) in this 19-year-old female patient with traumatic transverse ligament disruption.
86 CHAPTER 2 Cervical Spine
FIGURE 2–47 Jefferson fracture: Burst fracture of the atlas.44 A, Anteroposterior open-mouth radiograph shows lateral offset of the atlas relative to the axis seen as asymmetry of the periodontoid spaces with marked widening on the left side (arrows ). The left periodontoid space is not dilated because the lateral mass of C1 is fractured (curved arrows) and the medial fragment (*) is displaced toward the midline.
88 CHAPTER 2 Cervical Spine
In addition, the lateral masses of the atlas are significantly shifted to the left (white arrows). FIGURE 2–51 Odontoid fracture: type III.47,48,147 Coronal reformatted CT (A) and sagittal T2-weighted MR image (B) reveal a slightly displaced oblique fracture (arrow) extending from the base of the odontoid to the right and passes obliquely and inferiorly through the C2 vertebral body.
90 CHAPTER 2 Cervical Spine
Inferior articular processes of the vertebra above dislocate and become seated (locked) in front of the superior articular processes of the vertebra below, resulting in spinal canal and foraminal stenosis. Anterior vertebral body displacement is typically more than half the width of the vertebral body; this displacement increases during flexion but does not decrease during extension.
92 CHAPTER 2 Cervical Spine
Unilateral (or rarely bilateral) vertical, oblique, or crushing fracture of the articular process, most common at the C6 and C7 levels. Comminuted fracture of the vertebral body, usually sustained in car accidents and diving injuries.
94 CHAPTER 2 Cervical Spine
Progressive instability.52,167 A, Initial radiograph obtained at the time of the hyperflexion injury sustained in a motor vehicle accident reveals minimal cervical lordosis reversion and minimal C2 to C3 anterolisthesis.
96 CHAPTER 2 Cervical Spine
Acute bilateral apophyseal joint dislocation
The lateral radiograph taken at that time reveals persistent elevation of the C5-C6 facet joints with an associated focal kyphosis.
98 CHAPTER 2 Cervical Spine
Note the fracture of the spinous process of C7 (arrow) caused by the forceful impact of the posterior elements. In E, a lateral radiograph shows a triangular fracture of the anteroinferior corner of the C5 vertebral body (arrow).
102 CHAPTER 2 Cervical Spine
FIGURE 2–61 Hyperflexion-hyperextension sprain: segmental instability.61,62 This 26-year-old woman had severe neck and radiating arm pain after a rear-end car accident. A small radiolucent vacuum cleft (white arrow), which is not clearly visible on this reproduction, is present in the anterior fibers of the C5-C6 intervertebral disc.
104 CHAPTER 2 Cervical Spine
NORMAL
LEFT
7RIGHT
It should be noted that 2 to 3 mm of asymmetry in height of the articular processes is present in more than 45% of normal persons and may lead to false-positive diagnoses. Burst fractures of the cervical spine are typically sustained in motor vehicle collisions and diving injuries and result in neurological deficits in approximately 85% of patients.
106 CHAPTER 2 Cervical Spine
Intervertebral osteochondrosis Narrowing of intervertebral space Occurrence of intradiscal vacuum Disc calcification (rare) Often contributes to foraminal stenosis. 2-84 Widespread secondary degenerative disease Narrowing of the disc space and chondrocalcinosis of the annulus fibrosus, joint sheaths, apophyseal joints and articular cartilage.
112 CHAPTER 2 Cervical Spine
FIGURE 2–67 Degenerative disease of the spine A, Lateral cervical radiograph of a 71-year-old man shows extensive osteoarthritis of the apophyseal joints characterized by joint space narrowing and subchondral sclerosis. Osteoarthritis of the joint without cover appears as hypertrophy of the uncinate processes with horizontal cracks across the C5 and C6 vertebral bodies (black arrows), a phenomenon that is not called a pseudofracture.
114 CHAPTER 2 Cervical Spine
FIGURE 2–68, continued D, Frontal conventional tomogram clearly illustrates the sclerosis, hypertrophy, and osteophytes arising from the uncinate processes (arrows), and the associated narrowing of the uncovertebral articulations.
116 CHAPTER 2 Cervical Spine
FIGURE 2–70 Osteoarthritis (degenerative joint disease): apophyseal joints.71-73,173 A, Narrowing of the apophyseal joint space, osteophyte formation, and sclerosis throughout the cervical spine (arrows) were noted in this 77-year-old man. Lateral radiograph reveals extensive sclerosis of the articular processes from C2 to C5 combined with dramatic narrowing of the joint space of the apophyseal joints (arrows).
118 CHAPTER 2 Cervical Spine
FIGURE 2–72 Idiopathic calcification of intervertebral disc.74 A, In this child, a calcified mass in the neural foramen is seen on the oblique radiograph (curved arrow).
120 CHAPTER 2 Cervical Spine
Advanced changes. A thick layer of ossifi ed bone is present along the anterior aspect of the cervical
122 CHAPTER 2 Cervical Spine
The sagittal canal diameter, measured between the posterior aspect of the odontoid and the spinolaminar junction (white arrows), measures only 8 mm. In C, compression of the spinomedullary junction at the odontoid process anteriorly and the posterior arch of the atlas posteriorly (arrowhead) is evident on this sagittal T1-weighted (TR/TE, 600/12) spin-echo MR image.
124 CHAPTER 2 Cervical Spine
In this patient with early erosive changes, multiple intervertebral discs are narrowed and the vertebral endplates at C3-C4 are unclear (empty arrow). In C, severe narrowing of the disc space, indistinct and irregular endplates, and erosion, narrowing, and subluxation of the apophyseal joint are visible.
126 CHAPTER 2 Cervical Spine
In B, radiograph obtained during flexion shows an increase in the atlantodental space and a flexion subluxation of atlas with respect to axis. Radiograph obtained in flexion shows atlantoaxial instability (black arrows) and diffuse apophyseal joint ankylosis (white arrows).
128 CHAPTER 2 Cervical Spine
This patient has diffuse syndesmophyte formation at several levels and more prominent osteophyte formation at the C3-C4 level (arrows), perhaps secondary to excessive motion (open arrow)
130 CHAPTER 2 Cervical Spine
FIGURE 2–82 Psoriatic arthropathy A, A thin sheet of paravertebral ossification is seen extending across the anterior aspect of the lower cervical spine (arrows). The spinal outgrowths are non-marginal, arising from the central portion of the anterior aspect of the vertebral body.
132 CHAPTER 2 Cervical Spine
A sagittal T1-weighted MR (B) image shows extensive tophus eroding the odontoid with prevertebral (arrow) and epidural (arrowheads) extension of the tophaceous material. FIGURE 2–85 Retropharyngeal calcific tendinitis: calcium hydroxyapatite crystal deposition disease (HADD A, In this 46-year-old woman with neck pain, fever, and limitation of motion, a spherical collection of calcifications is seen in the soft tissues adjacent to the anterior aspect of the C2 vertebral body (arrow ).
134 CHAPTER 2 Cervical Spine
136 CHAPTER 2 Cervical Spine
FIGURE 2–91 Dialysis spondyloarthropathy.95,165 The radiograph of this hemodialysis patient shows intervertebral space destruction, vertebral endplate erosion, and vertebral body collapse at the C3-C4 level (upper arrow). A small erosion is visible on the lower part of the C4 vertebral body (lower arrow), and early narrowing of the C5-C6 disc space is also evident.
138 CHAPTER 2 Cervical Spine
Eccentric, expansive osteolytic lesion arising from the neural arch; isolated vertebral body involvement is uncommon and is usually associated with concurrent involvement of the posterior elements. With healing, the height of the pathologically collapsed vertebral body can be restored, a finding that is more common in younger individuals.
140 CHAPTER 2 Cervical Spine
FIGURE 2-93 Aggressive osteoblastoma.98 A, Lateral cervical spine radiograph of this 6-year-old boy shows a large, expansive lesion overlying the C2 to C5 cervical vertebrae (arrows).
142 CHAPTER 2 Cervical Spine
FIGURE 2–98 Osteoblastoma (conventional).184 A lateral radiograph of the cervical spine (A) reveals an osteolytic expansile lesion involving the spinous process of C6 (arrows). An axial CT scan, soft tissue window (B) reveals the extent of the osteolytic process (arrows) and a bone scan (C) clearly demonstrates a focal zone of intense uptake (arrow) within the lower cervical spine.
144 CHAPTER 2 Cervical Spine
Sagittal T1-weighted (TR/TE, 700/20) spin echo MR image (B) more clearly defines the extent (arrows) and nature of the tumor and its widespread soft tissue destruction and infiltration. FIGURE 2–104 Neurofibromatosis type I (von Recklinghausen disease).120,121 A, Note the posterior serration of the C2 and C3 vertebral bodies (black arrows), erosion of the C1 and C2 neural arches (white arrows), and the dramatically soft prevertebral spine. tissue proliferation (open arrows) caused by soft tissue neurofibromas.
148 CHAPTER 2 Cervical Spine
Rugger-jersey spine: Band-like sclerosis adjacent to the superior and inferior surfaces of the vertebral body. FIGURE 2–108 Acromegaly.128 Elongation of the vertebral bodies (double-headed arrow) with prominent bone proliferation (arrows) is characteristic of acromegaly.
150 CHAPTER 2 Cervical Spine
FIGURE 2–110 Herniated intervertebral disc.130 A, Computed tomography (CT) abnormalities: Transaxial soft tissue window computed tomography (CT) image shows a right paramedian foraminal disc protrusion (white arrows) with herniation of disc material into the right nerve root canal (black arrows). Bilateral neural arch resection Postlaminectomy instability Postlaminectomy kyphosis Laminoplasty 2-113 Decompression for spinal stenosis in which only.
152 CHAPTER 2 Cervical Spine
Anterior surgical fusion. Observe the thin linear zone of ossifi cation representing successful bone
Initial radiographs (not shown) revealed atlantoaxial subluxation and narrowing of the C5-C6 disc space secondary to disc degeneration. In addition, the graft material in the C5-C6 disc space became anteriorly dislodged (arrow), necessitating a new surgical procedure to repair this complication.
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Lateral mass screws 2-114 Can be used in combination with plates and longitudinal rods for posterior spinal fusions Cannula screws 2-51 Fixation of executioner and tooth fracture. Intervertebral disc replacements Used in discectomy with fusion to restore the intervertebral disc space Hydroxyapatite interbody graft 2-111 Coral-based hydroxyapatite graft material (sea coral).
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One cage placed in the C5-C6 disc space is properly aligned (upper arrow), while the cage placed in the C6-7 disc space is mispositioned—it is anteriorly displaced (lower arrow).
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Surgeons should be alerted to this abnormal location of the carotids prior to any cervical spine surgery. MR angiography is useful in the evaluation of the vertebral arteries Vertebral artery aneurysm6 2-118 Rare occurrence in the vertebral artery: vessel dilatation and possible dissection.
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The many anomalies, normal variations, and other sources of diagnostic error that occur in the thoracic spine can simulate disease processes (Table 3-2) and lead to misdiagnosis. This chapter describes most of the more common processes shown in Figures 3-3 through 3-8.
ALIGNMENT ABNORMALITIES
Accurate interpretation of thoracic spine radiographs in children requires a thorough understanding of normal developmental anatomy.
METABOLIC AND HEMATOLOGIC DISORDERS
THORACIC SPINE SURGERY
162 CHAPTER 3 Thoracic Spine
Irregularities of the edges of the upper and lower vertebral bodies are common just before the appearance of the apophyses of the secondary rings.
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H FIGURE 3–1, cont’d
The vertebral bodies are oval and prominent vascular notches (venous canals of Hahn) are present within the anterior margins (arrows). The neural arches are not fused to the vertebral bodies and the spinal canal appears proportionally wide.
166 CHAPTER 3 Thoracic Spine
Notches and roundings of the adjacent corners of the vertebral bodies are also clearly visible. FIGURE 3–6 Lateral hemivertebra.7,8 Observe the triangular appearance of the vertebral body in the lower thoracic spine.
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Hurler syndrome)
In this 3-year-old child, beak-like projections arising from the anteroinferior vertebral bodies are noted. FIGURE 3–11 Osteopetrosis.13,14,101 Dense osteosclerosis is noted along the superior and inferior vertebral endplates of the thoracic spine in this patient.
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Ankylosing spondylitis19,109 Advanced ankylosis and syndesmophyte formation lead to exaggerated thoracic kyphosis and distortion of the lumbar lordosis. Thoracolumbar injury21 3-27 Thoracolumbar compression fractures, burst fractures, or other hyperflexion distraction or hyperflexion shear injuries can result in the accentuation of the thoracic kyphosis.
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This flattening of the thoracic kyphosis and the anteroposterior diameter of the ribcage can lead to a condition called straight back syndrome. In this syndrome, the sagittal dimension of the thoracic cage (double-headed arrow) measures less than 13 cm in men and 11 cm in women (on a 72-inch source-image receptor distance [SID] chest radiograph).
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MR imaging is often recommended for the evaluation of children with congenital scoliosis or juvenile idiopathic scoliosis. In young people, the curve progresses faster than in idiopathic scoliosis.
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FIGURE 3–18 Scoliosis: neurofibromatosis type I (von Recklinghausen disease. A severe S-shaped scoliosis with multiple rib deformities and banded ribs is seen. The scoliosis associated with this disease can take one of two forms: the first is similar to conventional idiopathic scoliosis with a long curve; the other is dysplastic, can progress rapidly, and is a sharply angled, short-segment kyphoscoliosis.
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Transaxial CT scan shows extensive calcifi cation within both the T7-T8 disc
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Rare site for this injury; high probability of accompanying neurological deficit More common in young people. Approximately 15% of patients have neurological deficits and 40% have damage to internal abdominal organs.
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A low signal intensity is seen in the pregadolinium image (A) and a high signal intensity in the postgadolinium image (B), characteristic of a recently fractured vertebra. In the remote fracture, the signal intensity of the L1 vertebral body is the same as that of the adjacent vertebral bodies before (A) and after (B) administration of contrast agent.
188 CHAPTER 3 Thoracic Spine
