A comparative chemical and histochemical study of the chondrodystrophoid and nonchondrodystrophoid canine intervertebral disc.
The chemical composition of the intervertebral disc of 9-month-old chondrodystrophoid and nonchondrodystrophoid dogs was studied for collagen, noncollagenous protein and glycosaminoglycan. Content of these substances differed significantly between breeds. The differences were most marked in the nucleus pulposus; the noncollagenous protein content of the nonchondrodystrophoid breed was higher than in that of the chondrodystrophoid dogs. The total nitrogen value of the nonchondrodystrophoid nuclei pulposi was less than that of the corresponding chondrodystrophoid discs mainly because of the high collagen content of the latter discs. Histochemically, it was found that the nuclei pulposi of the nonchondrodystrophoid breed contains larger amounts of glycosaminoglycan than in the discs of the chondrodystrophoid breeds. (+info)
Extradural inflammation associated with annular tears: demonstration with gadolinium-enhanced lumbar spine MRI.
Annular tears are manifest on MRI as the high-intensity zone (HIZ) or as annular enhancement. Patients with annular tears may experience low back pain with radiation into the lower limb in the absence of nerve root compression. Inflammation of nerve roots from leak of degenerative nuclear material through full-thickness annular tears is a proposed mechanism for such leg pain. The aim of this study is to illustrate the appearance of extradural enhancement adjacent to annular tears in patients being investigated for low back pain with radiation into the lower limb(s). Sagittal T1- and T2-weighted spin echo and axial T1-weighted spin echo sequences were obtained in eight patients being investigated for low back and leg pain. In all patients, the T1-weighted sequences were repeated following intravenous gadopentetate dimeglumine (Gd-DTPA). Annular tears were identified at 12 sites in eight patients. Extradural inflammation appeared as a region of intermediate signal intensity replacing the fat between the posterior disc margin and the theca, which enhanced following Gd-DTPA. The inflammatory change was always associated with an annular tear, and in four cases directly involved the nerve root. Enhancement of the nerve root was seen in two cases. The findings may be relevant in the diagnosis of chemical radiculopathy secondary to inflammation at the site of an annular leak from a degenerating disc. (+info)
A clinico-pathological study of cervical myelopathy in rheumatoid arthritis: post-mortem analysis of two cases.
Two patients who developed cervical myelopathy secondary to rheumatoid arthritis were analyzed post mortem. One patient had anterior atlanto-axial subluxation (AAS) combined with subaxial subluxation (SS), and the other had vertical subluxation (VS) combined with SS. In the patient with AAS, the posterior aspect of the spinal cord demonstrated severe constriction at the C2 segment, which arose from dynamic osseous compression by the C1 posterior arch. A histological cross-section of the spinal cord at the segment was characterized by distinct necrosis in the posterior white columns and the gray matter. In the patient with VS, the upper cervical cord and medulla oblongata showed angulation over the invaginated odontoid process, whereas no significant pathological changes were observed. At the level of SS, the spinal cord was pinched and compressed between the upper corner of the vertebral body and the lower edge of the lamina. Histologically, demyelination and gliosis were observed in the posterior and lateral white columns. (+info)
Ten- to 15-year outcome of surgery for lumbar disc herniation: radiographic instability and clinical findings.
The most appropriate treatment for radiculopathy associated with disc pathology is still controversial. Since 1934, surgical treatment has consisted of hemilaminectomy and removal of the herniated material. Many authors believe that these procedures may cause degenerative spondylosis and vertebral instability. Several surgical methods have been proposed, but the long-term effects are still being debated. In addition there appear to be few well-designed outcome studies on the management of this disease. In the present study, 150 patients were selected for surgery with strict criteria and all treated with the standard technique. The series was evaluated by subjective analyses (Roland questionnaire; 120 patients), objective examinations (68 patients - 56.6%) and radiographic studies including dynamic views (analyzed by the Taillard and Boxall methods) to establish the presence of vertebral instability (50 patients - 41.6%). The subjective and objective analyses showed a high rate of good results. Radiographic studies showed vertebral instability in 30 cases, but only 9 were symptomatic. Recurrences were not observed and only a few patients suffered from leg pain. The standard procedure for lumbar disc herniation showed good results at 10- and 15-year follow-up. (+info)
Cervical spondylotic myelopathy in elderly people: a high incidence of conduction block at C3-4 or C4-5.
OBJECTIVES: To precisely localise the site of conduction block in elderly patients with cervical spondylotic myelopathy in the presence of multilevel compression shown by MRI. METHODS: A total of 44 patients aged 65 and older underwent serial intervertebral recording of spinal somatosensory evoked potentials (SSEPs) from either the intervertebral disc or the ligamentum flavum after epidural stimulation. The site of conduction block identified by abrupt reduction in size of the negative peak was designated as the 0 level with the other levels numbered in order of distance assigning a minus sign caudally. RESULTS: A single site of focal conduction block was disclosed in 42 patients, 23 (55%) at C3-4, 17 (40%) at C4-5, and two (5%) at C5-6. At these levels (0), the amplitude of the negative component was reduced (p<0.0001) to 29% and the area to 22%, with a concomitant increase (p<0.0001) of the initial positive component to 150% in amplitude and 293% in area as compared to the-2 level which was taken as the baseline (100%). CONCLUSIONS: A high incidence (95%) of focal conduction block at C3-4 or C4-5 with normal conduction at C5-6 and C6-7 characterises cervical spondylotic myelopathy in elderly people. Incremental SSEP studies documenting the site of conduction block will help exclude clinically silent cord compression, directing the surgical intervention to the appropriate level of concern. (+info)
Fungal spinal osteomyelitis in the immunocompromised patient: MR findings in three cases.
The MR imaging findings of fungal spinal osteomyelitis in three recipients of organ transplants showed hypointensity of the vertebral bodies on T1-weighted sequences in all cases. Signal changes and enhancement extended into the posterior elements in two cases. Multiple-level disease was present in two cases (with a total of five intervertebral disks involved in three cases). All cases lacked hyperintensity within the disks on T2-weighted images. In addition, the intranuclear cleft was preserved in four of five affected disks at initial MR imaging. MR features in Candida and Aspergillus spondylitis that are distinct from pyogenic osteomyelitis include absence of disk hyperintensity and preservation of the intranuclear cleft on T2-weighted images. Prompt recognition of these findings may avoid delay in establishing a diagnosis and instituting treatment of opportunistic osteomyelitis in the immunocompromised patient. (+info)
Lumbar intradiscal pressure after posterolateral fusion and pedicle screw fixation.
In vitro biomechanical testing was performed in single-functional spinal units of fresh calf lumbar spines, using pressure needle transducers to investigate the effect of posterolateral fusion (PLF) and pedicle screw constructs (PS) on intradiscal pressure (IDP), in order to elucidate the mechanical factors concerned with residual low back pain after PLF. IDP of 6 calf lumbar spines consisting of L4 and L5 vertebrae and an intervening disc was measured under axial compression, flexion-extension and lateral bending in the intact spine, PS, PLF and the destabilized spine. Relative to the intact spines, the destabilized spines showed increased IDP in all of lordings and moments. IDP under PS and PLF were significantly decreased in axial compression, extension and lateral bending loads (p<0.05). In flexion, IDP under PS and PLF increased linearly proportional to the magnitude of flexion moment and reached as high as IDP of the intact spines. These results demonstrated that despite an increase in the stiffness of motion segments after PLF and PS, significant high disc pressure is still generated in flexion. Flexibility of PS and PLF may cause increased axial load sharing of the disc in flexion and increased IDP. This high IDP may explain patients' persisting pain following PS and PLF. (+info)
Relationship of pain drawings to invasive tests assessing intervertebral disc pathology.
It has been found that the pain patterns in pain drawings are related to the presence of herniated disc identified by myelography. The purpose of this study was to determine whether the pattern of pain in the drawings or the type of pain indicated (aching, burning, numbness, pins and needles, stabbing) was related to the presence of symptomatic disc pathology identified by CT/discography. In a subgroup of patients who underwent myelography, the relationship of the drawings to myelographic findings was also investigated. Pain drawings were completed by 187 patients with low back and/or radicular pain who were undergoing CT/discography. The drawings were scored in two ways, first by the system described by Ransford and secondly by visual inspection. They were classified as being indicative, or not, of disc pathology. The CT/discograms were classified as disrupted, or not, and the pain responses were recorded upon injection of each disc, based on the similarity of the pain provoked to clinical symptoms. Among the 133 patients with discogenic pain confirmed by discography, 110 (82.7%) had pain drawings that were classified as indicative. Among the 45 patients without discogenic pain, 29 (64.4%) had pain drawings classified as non-indicative. Patients with discogenic pain used more symbols indicating burning pain and aching pain than did non-discogenic pain patients. Our results confirmed those reported earlier by Uden, who found a relationship between the pattern of pain in the drawings and myelographic findings. Pain drawings may be helpful in the diagnosis of symptomatic disc pathology. (+info)