Calcium pyrophosphate dihydrate crystal deposition disease as a cause of lumbar canal stenosis.

STUDY DESIGN: This study measured the incidence of calcium pyrophosphate dihydrate crystal deposition in specimens of ligamenta flava in consecutive patients undergoing decompressive laminectomy between 1984 and 1991. The results were compared to determine the difference between calcium pyrophosphate dihydrate-negative patients with lumbar canal spinal stenosis. OBJECTIVES: The results were compared with cadaver specimens and literature values to determine if calcium pyrophosphate dihydrate crystal deposition disease contributes to the thickening of the ligamentum flavum and thereby contributes to spinal stenosis. SUMMARY OF BACKGROUND DATA: Calcium pyrophosphate dihydrate crystal deposition disease has been described in the axial skeleton. Hypertrophy of the ligamentum flavum has been suggested to contribute to stenosis. The association of calcium pyrophosphate dihydrate disease and hypertrophied ligamenta flava has not been fully defined nor linked to neurologic symptoms and signs. METHODS: The incidence of calcium pyrophosphate dihydrate crystal deposition in specimens of ligamenta flava obtained from four groups was measured: specimens obtained during surgery from 102 consecutive patients undergoing decompression laminectomy between 1984 and 1991, 47 additional pathologic specimens of ligamentum flavum tested between 1984 and 1991, 222 calcium pyrophosphate dihydrate-positive Pathology Department specimens collected between 1980 and 1991, and, as control specimens from 20 cadavers. The associated patient histories were reviewed for the first two groups; no histories were available for the cadaver group. RESULTS: The incidence of calcium pyrophosphate dihydrate crystal deposition was 24.5% in the ligamentum flavum among the surgical patients, 31% among the Pathology Department specimens, 33.8% among the calcium pyrophosphate dihydrate-positive Pathology Department specimens, and 5% among the cadavers. No associated medical conditions with calcium pyrophosphate dihydrate crystal deposition were found among the medical histories. Patients with the symptoms of spinal stenosis who were also calcium pyrophosphate dihydrate-negative patients with symptoms of less than 6 months' and less than 24 months' duration (P < 0.001). Except for time to presentation, calcium pyrophosphate dihydrate-negative patients had similar signs and symptoms of lumbar canal spinal stenosis. Having previous spine surgery did not produce a statistically significant risk of having calcium pyrophosphate dihydrate crystal deposition. No specific laboratory tests were found to be of predictive value. CONCLUSIONS: These findings suggest that calcium pyrophosphate dihydrate crystal deposition may indeed be associated with the thickening of the ligamentum flavum, if so, patients may benefit from medical treatment before undergoing surgical treatment of lumbar canal spinal stenosis.

MRI diagnosis of tuberculous vertebral osteomyelitis.

Two patients with suspected tuberculous spondylitis and one patient with previous Pott's disease were evaluated preoperatively with magnetic resonance imaging (MRI). The MRI provided more exact anatomic localization of vertebral and paravertebral tuberculous abscesses in multiple planes not previously available with more conventional diagnostic methods in the patients with suspected tuberculous spondylitis. This was helpful for localization in planning of surgical approaches. In the patient with previous Pott's disease, spinal cord compression was detected using MRI, which showed no evidence of active tuberculosis. Two case reports are offered to show the benefit of using MRI as a diagnostic technique in preoperative evaluation and as a method of monitoring treatment response of tuberculous spondylitis. The third case shows the benefit of using MRI to rule out active infection and to detect other forms of spinal pathology.

Cervical spine injuries and their neurologic implications.

This article presents the neurologic implications of cervical spine injuries by reviewing (1) cervical spine anatomy, (2) initial patient evaluation, (3) the type of neurologic injuries that can occur, (4) the treatment of athletes with these injuries, and (5) criteria for returning to activity.

Cervical spine fractures in athletes.

This article presents (1) the on-field assessment of the athlete who has sustained a cervical injury, (2) the diagnostic modalities necessary to make an accurate diagnosis, (3) the specific fractures/dislocations seen in the cervical spine, and (4) the guidelines used to determine if the athlete may return to active competition.

High-resolution MR imaging of sequestered lumbar intervertebral disks.

We retrospectively reviewed the MR examinations of 20 patients with surgically documented sequestered lumbar disks (free fragments). Sixteen of 20 cases demonstrated extradural masses that were distinct from the interspace of origin and had intermediate signal on T1-weighted images but increased signal on T2-weighted images. In 12 cases there was migration of the sequestered fragment. Sequestered disks that migrated away from the interspace had an irregular, oblong appearance, while those near the interspace were round in configuration. Additionally, the interspace of origin consistently demonstrated loss of signal on T2-weighted images when compared with intact lumbar disks. Sagittal 12-weighted images best depicted the absence of a high-signal pedicle contiguous with the interspace of origin in sequestered disks. These findings were applied to a prospective group of 20 patients undergoing lumbar diskectomy. There was an 89% sensitivity, 82% specificity, and 85% accuracy for MR in distinguishing sequestered disks from other forms of lumbar disk herniation. We conclude that high-resolution MR imaging is sensitive in detecting disk disease and specific in characterizing various subtypes of extradural defects. MR uses morphology as well as changes in signal intensity to make these distinctions.

Vertebral osteomyelitis presenting as spinal compression fracture. Six patients with underlying osteoporosis.

Six patients with osteoporosis had vertebral osteomyelitis (VO) with infection of a single vertebra that presented with a collapsed vertebral body, thought to be a simple compression fracture. The resulting delay in correctly diagnosing VO was associated with disabling sequelae in a high proportion of cases. This distinctive presentation accounted for 13% of all hospitalized patients with VO and 2.4% of inpatients with osteoporotic compression fractures during the last five years; it may be more common than suggested by the paucity of published cases. In patients with osteoporosis and vertebral compression fractures, osteomyelitis should be considered when there is severe back pain, persistent unexplained fever, unexplained elevation of the erythrocyte sedimentation rate, or bacteremia without an obvious extravertebral focus of infection, particularly if the patient is immunocompromised. Early biopsy and culture of the collapsed vertebral body will facilitate diagnosis and therapy.

Arthrodesis of the shoulder. Current indications and operative technique.

This article describes the current indications, contraindications, and results of shoulder fusion. The preferred position, AO technique, and complications are described.

Computed tomography scanning after chymopapain injection for herniated nucleus pulposus. A prospective study.

Fifty consecutive patients treated with chymopapain injection for a clinical and radiographic diagnosis of herniated nucleus pulposus were evaluated prospectively. All patients had a prechymopapain computed tomography (CT) scan and a three-month postinjection CT scan. In addition, ten patients (20%) had a six-month postinjection CT scan. All scans were interpreted blindly. Only six patients (12%) had obvious changes in the size of the disc when preinjection and three-month postinjection CT scans were compared. By six months, however, seven of ten patients (70%) had obvious changes in their CT scan. Seven patients (14%) were considered chymopapain treatment failures and were later treated with surgical discectomy. Only two of these seven patients (30%) had obvious changes in their three-month CT scan. Chymopapain injection did not alter the size of the herniated portion of the disc during the first three months after chymopapain injection. A decision to operate for presumed chymopapain failure should therefore be based on clinical grounds, rather than on the three-month CT appearance of the herniated disc.

Effects of chemonucleolysis demonstrated by MR imaging.

In a study designed to assess the diagnostic and prognostic usefulness of magnetic resonance (MR) imaging in patients to be treated with chymopapain, 39 patients with a clinicoradiographic picture of herniated lumbar disk were scanned. Twenty-one of these, who were actually treated, were rescanned 3 months following the intradiskal administration of chymopapain. In both pretreatment and posttreatment scans sagittal T1 and T2 weighted spinecho technique was used. Prior to therapy, disks that were later injected demonstrated narrowing of the intervertebral disk space (95% of cases); an extradural defect (86% of cases); diminished signal intensity on the T1 weighted images (50% of cases); and decreased signal intensity on the T2 weighted image when compared with normal controls (100% of cases). Additionally, the adjacent endplates of the injected disk showed increased signal intensity on the T1 weighted image in 32%; 18% of the cases displayed increased signal intensity on the T2 weighted image. Following chymopapain, 100% of injected disks demonstrated decrease in disk height; 36% of the extradural defects diminished in size and 9% increased; 91% of injected disks showed loss of signal intensity on the T1 weighted image; and 86% lost signal in the T2 weighted study with 14% remaining unchanged. Vertebral body endplates adjacent to the level of injection demonstrated a decreased signal intensity on the T1 weighted image in 32% of cases, and 40% demonstrated increased signal in the T2 weighted study. Even though these findings could not be correlated with clinical success or failure using the criteria in this study, six of the original 39 patients were diagnosed as having free disk fragments on the basis of their initial MR scans, a fact that does have management implications for the use of chymopapain in treatment of herniated disk disease.

Lumbar herniated disk disease and canal stenosis: prospective evaluation by surface coil MR, CT, and myelography.

Sixty patients with suspected lumbar herniated disk and/or canal stenosis were studied prospectively with surface coil MRI, CT, and/or myelography, and the results were compared with the surgically confirmed abnormality. Forty-eight patients had lumbar surgery at 62 levels. There were no negative explorations. Thirty-nine patients had a myelogram and CT. Thirty of the CTs were performed following the injection of metrizamide for myelography. Nine patients had a CT without intrathecal contrast material 1 to several days before the myelogram. Six patients had myelography only, and three patients had CT only. All studies were evaluated for the location and type of disease in a forced choice fashion. Independent of the surgically correlated levels, there was 86.8% agreement between the MR and CT studies in all patients at 151 levels and 87.2% agreement between MR and myelography at 218 levels. At the operative levels, there was 82.6% agreement between MR and surgical findings for both type and location of disease; 83% agreement between CT and surgical findings; and 71.8% agreement between myelography and surgical findings. There was 92.5% agreement when MR and CT were used jointly, and 89.4% agreement when CT and myelography were used jointly. The results of this study indicate that a technically adequate MR examination was equivalent to CT and myelography in the diagnosis of lumbar canal stenosis and herniated disk disease. CT and MR can be complementary studies, and surface coil MR can be viewed as an alternative to myelography.

Spinal epidural hematoma and ankylosing spondylitis.

A typical case of ankylosing spondylitis (AS) in a 53-year-old man illustrates the high risk of spinal injury. When compared to the healthy subjects, patients with ankylosing spondylitis are at risk even after trivial injury. Spinal epidural hematoma is rare and generally associated with significant osseous spinal column involvement. Although rare, hematoma should be considered in ankylosing spondylitis patients, when a patient develops progressive neurologic symptoms and signs. An aggressive approach, including early decompression, affords the best chance for recovery.

Cervical myelopathy: a comparison of magnetic resonance and myelography.

Fifty-seven patients with a strong clinical suspicion of cervical myelopathy were studied with body coil magnetic resonance (MR) and conventional myelography or CT myelography. Eight patients were believed to have normal studies with both modalities. There were six patients with syringomyelia; four with an intramedullary tumor; one with an arteriovenous malformation; 19 with cervical spondylosis at multiple levels; eight with cervical spondylosis at a single level; four with extensive rheumatoid arthritis; four with extradural neoplasm; two with trauma; and one patient with an epidural abscess. In this study, body coil MR was the superior examination for the evaluation of an intramedullary process. It was as diagnostic as myelography in one case of an extramedullary intradural lesion. In patients with extradural disease, body coil MR was the superior study in 45%, equivalent to myelography in 37%, and, although still diagnostic, inferior to myelography in 17%. In 8% of the cases, body coil MR was at best equivocal, whereas myelography was diagnostic. It appears that in technically adequate studies, MR is at least equivalent to myelography in its ability to delineate disease. A superior MR study provides a better appraisal of the size and character of the spinal cord as well as the degree of both anterior and posterior defects on the subarachnoid space and neural structures. In addition, MR is as good as conventional myelography for the identification of extrinsic cervical cord lesions producing cervical myelopathy. Finally, an additional small group of 30 patients were studied with a prototype surface coil to determine its advantages relative to body coil imaging. Each patient had correlative myelography. As with body coil MR, imaging with the surface coil was believed to be more informative than conventional myelography in four patients with intramedullary lesions. The remaining 26 patients suffered from cervical spondylosis. Surface coil MR was believed to be more informative than myelography in six cases (23%), equivalent to myelography in 19 (73%), and less diagnostic than myelography in one (4%). The improved spatial resolution with the use of the surface coil was believed to increase the accuracy of MR.

Vertebral osteomyelitis: assessment using MR.

Thirty-seven patients who were clinically suspected of having vertebral osteomyelitis were prospectively evaluated with magnetic resonance (MR), radiography, and radionuclide studies. These findings were correlated with the final clinical, microbiologic, or histologic diagnoses. Based on the results of these latter studies, 23 patients were believed to have osteomyelitis. MR examinations consisted of at least a sagittal image (TE = 30 msec, TR = 0.5 sec) and an image obtained at TE = 120 msec, TR = 2-3 sec. All patients underwent radiographic and MR examinations, 36 underwent technetium 99m-HDP bone scanning, and 20 patients underwent gallium 67 scanning. Nineteen patients underwent both bone and gallium scanning. The imaging studies were reviewed independently by investigators blinded to the final diagnoses. MR had a sensitivity of 96%, specificity of 92%, and accuracy of 94%. Combined gallium and bone scan studies (19 cases) had a sensitivity of 90%, specificity of 100%, and accuracy of 94%. Bone scans alone had a sensitivity of 90%, specificity of 78%, and accuracy of 86%. Plain radiographs had a sensitivity of 82%, specificity of 57%, and accuracy of 73%. The MR appearance of vertebral osteomyelitis in this study was characteristic, and MR was as accurate and sensitive as radionuclide scanning in the detection of osteomyelitis.

Nuclear magnetic resonance of the spine: clinical potential and limitation.

Magnetic resonance can visualize the vertebral bodies, discs, neural structures, cerebrospinal fluid (CSF), neural foramina, and extradural structures in the sagittal, axial, and coronal planes. The normal nucleus pulposus can be differentiated from the anulus and changes associated with degeneration. Infection, trauma, and neoplastic conditions can be identified. The signal intensity of the CSF relative to extradural and neural structures can be increased to provide evaluation of the size and configuration of the contents of the thecal sac without the use of an intrathecal contrast medium. Impingement by disc, tumors, fracture segments, and expansile masses can then be accurately evaluated. It is the most accurate modality for the evaluation of the foramen magnum, Chiari malformation, syringomyelia, infection, and degeneration of intervertebral discs. It can identify paravertebral soft tissue and bony changes when plain films and computed tomographic (CT) studies are negative or equivocal. Not only can lesions be localized, but significant information regarding the nature of the process can be obtained. Using variations of the spin-echo technique with appropriate T1 and T2-weighted images, magnetic resonance can produce tissue contrast distinctions not possible with CT scans or conventional angiography.

Magnetic resonance imaging of intervertebral disk disease. Clinical and pulse sequence considerations.

Sixty-five patients were examined with magnetic resonance imaging (MR) to determine what combination of operator-selectable controls would result in a thorough examination of the intervertebral disks. There were 20 normal subjects, 8 with degenerative lumbar disk disease, 27 with both degeneration and herniation, 5 with stenosis of the spinal canal, and 5 with disk space infection. T2 was significantly longer in the normal nucleus pulposus than in the degenerated disk. Based on plots of in vivo signal intensity vs. repetition time (TR) for various echo times (TE), a sagittal 30-msec. TE and a 0.25-sec. TR were used for anatomical delineation and rapid localization, while sagittal and/or axial 120-msec. TE/3-sec. TR images were used to evaluate the cerebrospinal fluid and disk. Comparison with radiographs, high-resolution CT scans, and myelograms showed that MR was the most sensitive for identification of degeneration and disk space infection, separating the normal nucleus pulposus from the annulus and degenerated disk. Herniation, stenosis of the canal, and scarring can be identified as accurately with MR as with CT or myelography.

Magnetic resonance imaging of the cervical spine: technical and clinical observations.

Seventy-two patients were examined to determine the clinical potential for magnetic resonance imaging (MRI) of the spine. MRI using different pulse sequences was compared with plain radiography, high-resolution computed tomography, and myelography. There were 35 normal patients; pathologic conditions studied included canal stenosis, herniated disk, metastatic tumor, neurofibroma, trauma, Chiari malformation, syringomyelia, arteriovenous malformation, and rheumatoid arthritis. MRI provided sharply defined anatomic delineation and tissue characterization. It was diagnostic in syringomyelia and Chiari malformation and was useful in the evaluation of trauma and spinal canal block from any cause. MRI was sensitive to degenerative disk disease and infection. The spin-echo technique, with three pulse sequence variations, seems very promising. A short echo time (TE) produces the best signal-to-noise ratio and spatial resolution. Lengthening the TE enhances differentiation of various tissues by their signal intensity, while the combined increase of TE and recovery time (TR) produces selective enhancement of the cerebrospinal fluid signal intensity.

Nuclear magnetic resonance imaging of the spine.

Forty subjects were examined to determine the accuracy and clinical usefulness of nuclear magnetic resonance (NMR) examination of the spine. The NMR images were compared with plain radiographs, high-resolution computed tomograms, and myelograms. The study included 15 patients with normal spinal cord anatomy and 25 patients whose pathological conditions included canal stenosis, herniated discs, metastatic tumors, primary cord tumor, trauma, Chiari malformations, syringomyelia, and developmental disorders. Saturation recovery images were best in differentiating between soft tissue and cerebrospinal fluid. NMR was excellent for the evaluation of the foramen magnum region and is presently the modality of choice for the diagnosis of syringomyelia and Chiari malformation. NMR was accurate in diagnosing spinal cord trauma and spinal canal block. The normal disc was seen, but with rare exceptions bulging of the annulus and herniation of the nucleus pulposus were not visualized.