Fusion of the lateral joints in fixed atlantoaxial dislocation: a computed tomography demonstration

Fixed atlantoaxial dislocation is a well-known phenomenon that may partially account for the discrepancy between the radiographic and neurologic abnormalities seen in rheumatoid arthritis of the craniocervical region. In this care report, "arthritis rigidity" is demonstrated by computed tomography to be due to fusion of the occipitoatlantoaxial complex, following erosion and disruption of these joints by rheumatoid disease.

Fibrobullous disease of the upper lobes: an extraskeletal manifestation of ankylosing spondylitis

Fibrobullous disease of the upper lobes of the lungs is a rare extraskeletal manifestation of ankylosing spondylitis, occurring in 1.3% of patients with ankylosing spondylitis. We present a patient with this disease, and discuss this pulmonary manifestation. Because the radiographic appearance of the chest in this disease resembles that in tuberculosis, many patients are misdiagnosed and treated for tuberculosis despite negative bacteriology. Computed tomography is useful in delineating the extent of pleural thickening, bullous changes, volume loss, parenchymal fibrosis, and bronchiectasis, as well as identifying or excluding an intracavitary pulmonary mycetoma.

Computed tomography in localization of foreign bodies lodged in the extremities

Surgical removal of foreign objects (FO) lodged in the body may be difficult because of uncertain 3-dimensional localization on conventional roentgenograms. Furthermore, low-density FO may not be detectable on roentgenograms. CT was performed in 8 patients with FO lodged in the extremities, and was found helpful because, (1) it detected 4 low-density FO's missed on roentgenograms, and (2) it facilitated surgical removal by displaying the precise 3-dimensional location of these objects.

Computed tomography of tibial plateau fractures

Open reduction with internal fixation of tibial plateau fractures in performed frequently. Factors that must be considered in planning treatment include the patient's age and physical condition, the presence and degree of plateau depression, the presence and degree of separation of split fragments, and the severity of fracture comminution. Twenty patients with tibial plateau fractures were studied by conventional tomography and computed tomography (CT) in order to determine the role and feasibility of CT in management of such patients. CT resulted in less discomfort to the patient and provided optimal visualization of the plateau defect and the split fragments. It proved more accurate than conventional tomography in assessing depressed and split fractures when they involved the anterior or posterior border of the plateau and in demonstrating the extent of fracture comminution. Split fragments with an oblique plane of fracture also were seen better by CT. The degree of fracture depression and separation as measured by the computerized technique was often more accurate than measurements obtained from conventional tomograms. In three patients, treatment was changed on the basis of the CT findings. In three other cases, the classification was altered without a change in treatment.

Computed tomography of thoracic and lumbar spine fractures that have been treated with Harrington instrumentation

Twenty patients with fractures of the thoracic and lumbar spine underwent computed tomography (CT) following Harrington distraction instrumentation and spinal fusion. CT was done to search for a cause of persistent cord or nerve root compression in those patients who failed to improve and completely recover their partial neurologic deficit (14 cases). In 6 patients seen in the late recovery period, CT was performed to evaluate the causes of pain and instability at the fracture site. Even though the image was degraded due to the artifacts generated by the metallic rods, significant information was available in each case. The most common abnormality was the presence of residual bone fragments originating in the burst fracture of a vertebral body displaced posteriorly, into the spinal canal. In patients with complications in the late recovery period, CT found exuberant callus indenting the canal or lack of fusion of the bone grafts placed in the anterolateral aspect of the vertebral bodies. This experience indicates that CT is the modality of choice for spinal canal evaluation in those patients who fail to have an optimal clinical course following fractures of the thoracic and lumbar spine treated with Harrington rods.

Quantitative computed tomography assessment of spinal trabecular bone. II. In osteoporotic women with and without vertebral fractures

Computed tomography was utilized to measure the bone mineral content of the spinal trabecular bone in 96 osteoporotic women. A significant overlapping was found between the values obtained for these patients and the age-matched normal values. Sixty-six percent had bone mineral content values below the fifth percentile for age-matched normals. Eighty-five percent of those with vertebral fractures had bone mineral content values below the fifth percentile for normal premenopausal women (fracture threshold). It is suggested that diagnosis of osteoporosis be made when the spinal bone mineral content value is below the fracture threshold.

Quantitative computed tomography assessment of spinal trabecular bone. I. Age-related regression in normal men and women

Computed tomography, utilized in conjunction with a calibrated phantom containing a set of reference densities (K2HPO4 and water), is capable of determining the mineral content of the trabecular bone of the spine with an accuracy of about 6% of the ash weight of the vertebrae scanned (specimen studies). Other modalities measure a composite of cortical and trabecular bone. Computed tomography is capable of exclusively measuring the mineral content of the trabecular bone of the spine, where the earliest and most pronounced changes of spinal osteoporosis occur. Quantitative computed tomography measurements are useful for a precise and objective assessment of the spinal mineral content and its changes with age, disease, and drugs.

CT of lumbar spine disk herniation: correlation with surgical findings

Computed tomography (CT) of the lumbar spine was performed with selectively positioned 5-mm-thick axial cross sections to examine each disk level from the top of the neural foramen to the pedicle of the next caudad vertebra. One hundred consecutive patients with 116 surgical disk explorations were reviewed. There was agreement between the CT and surgical findings in 89 patients (104 explorations) in determination of presence or absence of a herniated nucleus pulposus (HNP). Discrepancy occurred in 12 instances (11 patients): two because of incorrect interpretations, five in previously operated patients, three in spondylolisthesis, and two in spinal stenosis. There were 97 true-positives, eight false-negatives, seven true-negatives, and four false-positives. If nine previously operated patients are excluded from the study, then CT was accurate in detection of presence or absence of an HNP in 93% of the disk explorations.

Acute traumatic fibular bowing associated with tibial fractures

Acute traumatic fibular bowing associated with angular fracture of the tibia was observed in three young adults. The fibular bowing may have had a negative effect on the healing of the tibial fracture by transmitting tension through the interosseous membrane, thereby preventing proper reduction of the tibial fracture fragments and delaying the union.

CT of osteomyelitis of the spine

Computed tomography (CT) were performed in 17 adults with osteomyelitis of the spine. The dominant features were paravertebral soft-tissue swelling, abscess formation, and bone erosion. In two patients there were no findings indicative of osteomyelitis on conventional radiographs, but CT revealed paravertebral abscesses and bone lysis, helping to establish the diagnosis of osteomyelitis. CT was found helpful in the evaluation of the patients suspected of spinal osteomyelitis, chiefly because of its ability to detect early erosion of spongy vertebral bone, disk involvement, paravertebral soft-tissue swelling or abscess, and extension of the pathology into the spinal canal. Furthermore, CT facilitated closed-needle biopsy, helping to establish the pathologic diagnosis.

Computed tomography of the sacroiliac joints: comparison with complex-motion tomography

Forty-seven patients with sacroiliac joint abnormalities were examined with computed tomography and conventional complex-motion tomography. Twenty-nine patients had spondyloarthritis. Of the 29, complex-motion tomography detected bone erosions in 16 patients, whereas computed tomography revealed erosions in nine. Computed tomography was more sensitive in detection of joint narrowing, joint widening, osteosclerosis, and intraarticular bony ankylosis. In the remaining 13 patients, computed tomography was the modality of choice in detection of paraarticular soft tissue pathology, such as abscess or tumor, and in detection of the lesions involving the sacral canal and neural foramina.

Computerized tomography of pelvic osteomyelitis in patients with spinal cord injuries

Computerized tomography (CT) was performed in 19 patients with spinal cord injury (SCI) who had large pressure sores and in whom other complications were suspected. CT detected the depth, extent, and degree of undermining of the edges of the pressure sores in 19 of 27 lesions. Conventional radiography detected four cases of pelvic osteomyelitis. CT detected eight additional cases of pelvic osteomyelitis, as well as eight clinically unsuspected peripelvic and intrapelvic abscesses. Technetium-99m bone scanning was not very helpful because of localization in chronic proliferative changes of bone and widespread foci of myositis ossificans, as well as in osteomyelitis. Gallium-67 scanning detected only one of six abscesses. It was not very helpful because of confusion of abscess and osteomyelitis with intense soft tissue swelling and cellulitis, which are often associated with pressure sores in patients with chronic SCI. CT was found to be, by far, the modality of choice for detection of pelvic osteomyelitis and abscess in patients with SCI.

Hypertrophic osteoarthropathy in metastatic renal cell carcinoma

Clinical signs of hypertrophic osteoarthropathy developed in a thirty-eight-year-old man with metastatic hypernephroma. Roentgenograms of the extremities detected the characteristic periosteal reaction along the radius, ulna, metacarpals, femur, tibia, and fibula, bilaterally. The pathogenesis of this syndrome is unknown; it appears to be mediated by a pathologic reflex with the vagus nerve as the afferent limb. When seen in patients with renal cell carcinoma, hypertrophic osteoarthropathy may herald the development of intrathoracic metastases.

Computerized tomography of the Cupid's bow contour of the lumbar spine

The inferior endplates of the third, fourth, and fifth lumbar-vertebral bodies frequently have paired parasagittal concavities when viewed in the frontal projection. In the lateral projection, these concavities lie posteriorly and are superimposed. This has been called Cupid's bow contour of the spine. On CT, Cupid's bow is visualized in an axial plane as two rounded relatively well-circumscribed areas of hypodensity rimmed by apparant osteosclerosis in the posterior half of the vertebral bodies. This, on occasion, may resemble metastasis or other pathology of the spine. The CT features, however, once appreciated, are characteristic of this normal variant, helping to distinguish it from other contour deformities of the vertebrae having clinical significance. The CT features are described and the incidence is discussed in 100 patients.

Computerized tomography in diagnosis of pelvic abscess in spinal-cord-injured patients

Twenty-four spinal-cord-injured patients with pressure sores, and suspected of having other complications were studied by CT, gallium scanning, and ultrasonography. CT was found to be by far the modality of choice for evaluation of the extent and depth of the pressure sore, assessment of the thickness of fibrous tissue scar alongside its boundaries and at its base, detection of associated peri-pelvic and intra-pelvic soft tissue abscesses, sinus tracts and osteomyelitis of the pelvic bones.

Computed tomography of traumatic serosanguineous cysts

Two patients developed traumatic peripelvic serosanguineous cysts, following pelvic fracture. A serosanguineous cyst develops when shearing forces cause separation of the skin and subcutaneous fat from the deep fascia and muscle. The space thus created is filled with serious fluid and blood, and clinically presents as soft cystic masses, appearing usually within a day or so, or rarely, after several weeks or months. Most of these lesions resolve spontaneously, or following aspiration; however, some may persist, necessitating surgical resection. Computed tomography is the modality of choice for detection and, in those cysts requiring surgery, it is helpful in revealing the exact size and location of these lesions.

Pathologic fracture in systemic mastocytosis. Radiographic spectrum and review of the literature

Systemic mastocytosis is a multiorgan disease that most commonly affects the skin and skeletal system. Radiographically, the skeletal changes in the majority of patients consist of either a wide-spread mixture of bone lysis and osteosclerosis or generalized osteoporosis. The osteoporotic form is less well known but may lead to severe generalized demineralization and pathologic fractures. Mast cells secrete a number of substances, two of which (heparin and prostaglandins) are believed to have a role in the induction of osteoporosis. Sclerotic lesions are induced by another mast cell by-product, histamine. One hundred seventy-eight cases of bony mastocytosis have been reported in the literature, including the four patients in the present report. Special staining procedures are necessary for identification of mast cells. Diagnosis may be delayed in patients who do not have the skin lesions (urticaria pigmentosa) and in the osteoporotic form of the disease.

Computerized tomography in diagnosis of compression of the common peroneal nerve by ganglion cysts

A 48-yr old man noted gradual onset of pain, and paresthesia on the lateral aspect of his right leg. The findings were suggestive of S1 root compression. CT of spine was normal. Physical examination revealed a small mass overlying the right fibular head. CT revealed this to be a cystic mass. At surgery a ganglion cyst compressing the common peroneal nerve was found. Peripheral nerves may be compressed by ganglia producing a syndrome mimicking central nerve root compression. CT is the modality of choice for detection of these lesions.

Computed tomography of pressure sores

Twenty-three paralyzed patients admitted for treatment of recurrent pressure sores were evaluated by computed tomography, bone scanning, gallium scanning, and sonography. Computed tomography was helpful in detecting associated peripelvic and pelvic abscesses and pelvic osteomyelitis, which were undiagnosed by all other modalities combined in more than half of the patients. Computed tomography was also useful in preoperative planning by revealing the extent of the undermining of the pressure sore, the thickness of the fibrous scar at its base, and the size and status of the adjacent muscles.

The impact of CT in clinical management of pelvic and acetabular fractures

Thirty-eight consecutive patients admitted to the hospital with pelvic and acetabular fractures underwent CT examination. The axial plane of CT is shown to be the most suitable for evaluation of these fractures. The fracture pattern is readily demonstrated, facilitating fracture classification. The degree of fracture fragment displacement and rotation, hip joint stability, and intra-articular osseous fragments can be determined. A number of unsuspected fractures were detected, including five sacral and four anterior acetabular wall fractures; the latter were due to extension of superior ramus fractures. Soft tissue injuries included several hematomas, serosanguinous cysts in one patient, and bladder laceration in one patient. It is concluded that in patients with pelvic fracture CT examination is the method of choice following preliminary radiographic evaluation, if further radiographic investigation is deemed necessary.

Use of CT-guided percutaneous bone biopsy in staging of genitourinary tumors

CT-guided needle aspiration biopsy has been used for staging of genitourinary tumors. The display of structures provided by CT is particularly suited for complex anatomic sites such as spine, pelvis, thorax, permitting selection of the shortest and safest route for the needle, away from the aorta, vena cava, and pleural surface. Another advantage of CT is its ability to detect soft tissue components of the tumors and the presence of central necrosis therefore targetting the biopsy toward the part of the lesion with the greatest diagnostic yield.

Computed tomography of pressure sores, pelvic abscess, and osteomyelitis in patients with spinal cord injury

Nine patients with spinal cord injury (SCI) and large pressure ulcers and other possible complications, were evaluated by computed tomography (CT), conventional radiography, tomography, bone scanning, gallium scanning, and sonography. CT revealed the depth, extent, and relationship of the ulcer-bed to the underlying structures in all 9 patients. CT also positively identified unsuspected intra- and extra-pelvic abscess and pelvic osteomyelitis in 4 patients each. Other modalities identified only 2 of these complications. We believe CT is the modality of choice for evaluation of these complications in SCI patients, because of its superior ability in evaluation of pressure sores and detection of pathologic changes in soft tissue and bone in the pelvic region.

Bilateral acetabular stress fractures in a paraplegic patient

Advances in rehabilitation programs have enabled many paraplegic persons to take part in activities in which the risk of trauma and skeletal injuries is comparable to that in the general population. Stress or spontaneous fractures are known to occur mainly as a result of severe osteoporosis and uncontrollable motion following removal of leg braces. However, stress fractures due to repeated minor trauma or prolonged physical activity have not been previously observed in paraplegic persons. In this report, bilateral acetabular stress fractures are described in a young paraplegic man during the course of ambulation therapy. The pattern of ambulation in these patients, who attempt to walk with crutches while their legs are placed in braces, is one contributing factor to stress fracture. Because of the paucity of physical findings and absence of pain, these fractures may go unrecognized, which can lead to more serious complications.