Locations of spinothalamic tract axons in cervical and thoracic spinal cord white matter in monkeys.
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The spinothalamic tract (STT) is the primary pathway carrying nociceptive information from the spinal cord to the brain in humans. The aim of this study was to understand better the organization of STT axons within the spinal cord white matter of monkeys. The location of STT axons was determined using method of antidromic activation. Twenty-six lumbar STT cells were isolated. Nineteen were classified as wide dynamic range neurons and seven as high-threshold cells. Fifteen STT neurons were recorded in the deep dorsal horn (DDH) and 11 in superficial dorsal horn (SDH). The axons of 26 STT neurons were located at 73 low-threshold points (<30 microA) within the lateral funiculus from T(9) to C(6). STT neurons in the SDH were activated from 33 low-threshold points, neurons in the DDH from 40 low-threshold points. In lower thoracic segments, SDH neurons were antidromically activated from low-threshold points at the dorsal-ventral level of the denticulate ligament. Neurons in the DDH were activated from points located slightly ventral, within the ventral lateral funiculus. At higher segmental levels, axons from SDH neurons continued in a position dorsal to those of neurons in the DDH. However, axons from neurons in both areas of the gray matter were activated from points located in more ventral positions within the lateral funiculus. Unlike the suggestions in several previous reports, the present findings indicate that STT axons originating in the lumbar cord shift into increasingly ventral positions as they ascend the length of the spinal cord. (+info)
Bilateral thoracic bifurcation of the common carotid artery associated with Klippel-Feil anomaly.
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We report the case of a 72-year-old man with bilateral intrathoracic carotid bifurcations associated with a Klippel-Feil anomaly. The left and right carotid bifurcations were located at levels corresponding to the second and fourth thoracic vertebrae, respectively. A possible association between low carotid bifurcation and the Klippel-Feil anomaly is suggested. (+info)
The reliability of the three-dimensional FASTRAK measurement system in measuring cervical spine and shoulder range of motion in healthy subjects.
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OBJECTIVES: To assess the inter-observer and intra-observer reliability of a new three-dimensional measurement system, the FASTRAK, in measuring cervical spine flexion/extension, lateral flexion and rotation and shoulder flexion/extension, abduction and external rotation in healthy subjects. METHODS: The study was conducted in two parts. One part assessed inter-observer reliability with two observers measuring 40 subjects. The other part assessed intra-observer reliability with one observer measuring 32 subjects on three occasions. All subjects had unrestricted, pain-free cervical spine and shoulder movement. Reliability was measured by the intraclass correlation coefficient [ICC(2,1)]. RESULTS: The inter-observer ICCs for the cervical spine ranged from 0.61 to 0.89 and for the shoulder from 0.68 to 0.75. After removal of outliers, all ICCs were above 0.70. Intra-observer ICCs for the cervical spine ranged from 0.54 to 0.82 and for the shoulder from 0.62 to 0.81. After removal of outliers, all ICCs were above 0.70 except for shoulder abduction (0.62). CONCLUSIONS: Whilst all movements measured by the FASTRAK showed good reliability, the reliability of the whole movement in a plane (e.g. left plus right lateral flexion) was better than for the separate movements (e.g. left and right lateral flexion taken separately). Inter-observer reliability was generally better than intra-observer reliability for most cervical spine movements, suggesting that variability of movement within subjects (e.g. over a period of days) for these movements was greater than variability between measures on the same occasion. (+info)
Load-displacement properties of the normal and injured lower cervical spine in vitro.
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The objective of this study was to determine which discoligamentous structures of the lower cervical spine provide significant stability with regard to different loading conditions. Accordingly, the load-displacement properties of the normal and injured lower cervical spine were tested in vitro. Four artificially created stages of increasing discoligamentous instability of the segment C5/6 were compared to the normal C5/6 segment. Six fresh human cadaver spine segments C4-C7 were tested in flexion/extension, axial rotation, and lateral bending using pure moments of +/- 2.5 Nm without axial preload. Five conditions were investigated consecutively: (1) the intact functional spinal unit (FSU) C5/6; (2) the FSU C5/6 with the anterior longitudinal ligament and the intertransverse ligaments sectioned; (3) the FSU C5/6 with an additional 10-mm-deep incision of the anterior half of the anulus fibrosus and the disc; (4) the FSU C5/6 with additionally sectioned ligamenta flava as well as interspinous and supraspinous ligaments; (5) the FSU C5/6 with additional capsulotomy of the facet joints. In flexion/extension, significant differences were observed concerning range of motion (ROM) and neutral zone (NZ) for all four stages of instability compared to the intact FSU. In axial rotation, only the stage 4 instability showed a significantly increased ROM and NZ compared to the intact FSU. For lateral bending, no significant differences were observed. Based on these data, we conclude that flexion/extension is the most sensitive load-direction for the tested discoligamentous instabilities. (+info)
A systematic literature review to identify the best method for a single level anterior cervical interbody fusion.
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The goal of this systematic literature review was to determine, for patients with degenerative disc disease, which method of single-level anterior cervical interbody fusion using the anterior approach gives the best clinical and radiological outcome. The number of new techniques for obtaining a solid fusion has increased rapidly, but the rationale for choosing between different techniques is unclear. Randomised comparative studies on anterior cervical interbody fusions were identified in a sensitive Medline, Cochrane and Current Contents database search. Two independent reviewers evaluated the articles that met the selection criteria, using a checklist. The search yielded eight randomised, controlled trials for the systematic literature review. Three of these studies were judged to be of sufficient quality with regard to methodology and the information provided. In the three articles, five different treatment methods were investigated, four of which were interbody fusions. Fusion rates varied between 28% for an allograft method and 63% for a discectomy-alone method. In one study, kyphosis varied from 40% to 62% between treatments. Good clinical outcome (disability, pain and symptoms) ratings varied from 66% to 82%. A meta-analysis to determine the best method for an anterior interbody fusion could not be performed due to the heterogeneity of the methods reported and because no standard outcome parameter was used. From this systematic literature review, a gold standard for the treatment of degenerative disc disease could not be identified. (+info)
Outcome scores in degenerative cervical disc surgery.
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Forty-six consecutive patients with neck pain and arm radiculopathy were treated with anterior cervical discectomy and fusion. All patients had neurological symptoms corresponding to a herniated disc and/or spondylosis at one or two cervical levels, verified by magnetic resonance imaging. The patients were stabilized with an anterior graft and randomized to either fixation with a CSLP plate or no internal fixation. Preoperatively and 2 years postoperatively the patients filled in a questionnaire that included a modified Million Index, a modified Oswestry Index and the Zung Depression Scale. They were also asked to register their pain in the arm and in the neck on a vertical visual analogue scale (VAS). At the 2-year follow-up, an unbiased observer graded the patients' clinical outcome using Odom's criteria. A test-retest procedure was carried out to examine the questionnaire reproducibility. In the group that was operated at one level, there was no significant improvement in any of the scores. Nevertheless, 81% of the patients were satisfied with the outcome of the surgery. All scores improved in the group operated at two levels. The pain in the neck and arm, as measured on a VAS, decreased in both groups. The improvement in arm pain was significantly more pronounced in patients operated with a plate at two levels compared to those who were operated without a plate. At the 2-year follow-up, patients with an excellent or good result according to Odom's criteria had a lower Million Index (P < 0.0005), Oswestry Index (P < 0.0005), and Zung (P = 0.024) score, than the group classified as fair or poor. There was a significant correlation (P < 0.0001 for all scores) between the test and retest results. We conclude that the modified Million Index and Oswestry Index are clinically useful tools in the evaluation of outcome after degenerative cervical disc surgery. The clinical benefits of plate fixation were minimal. The outcome after surgery, measured with the Oswestry Index, Million Index and VAS for arm and neck pain, seems to correlate well with the classification of outcome by Odom. (+info)
Boomerang deformity of cervical spinal cord migrating between split laminae after laminoplasty.
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Patients with cervical compression myelopathy were studied to elucidate the mechanism underlying boomerang deformity, which results from the migration of the cervical spinal cord between split laminae after laminoplasty with median splitting of the spinous processes (boomerang sign). Thirty-nine cases, comprising 25 patients with cervical spondylotic myelopathy, 8 patients with ossification of the posterior longitudinal ligament, and 6 patients with cervical disc herniation with developmental canal stenosis, were examined. The clinical and radiological findings were retrospectively compared between patients with (B group, 8 cases) and without (C group, 31 cases) boomerang sign. Moderate increase of the grade of this deformity resulted in no clinical recovery, although there was no difference in clinical recovery between the two groups. Most boomerang signs developed at the C4/5 and/or C5/6 level, where maximal posterior movement of the spinal cord was achieved. Widths between lateral hinges and between split laminae in the B group were smaller than in the C group. Flatness of the spinal cord in the B group was more severe than in the C group. In conclusion, the boomerang sign was caused by posterior movement of the spinal cord, narrower enlargement of the spinal canal and flatness of the spinal cord. (+info)
Improved medical and surgical management of cervical spine disease in patients with rheumatoid arthritis over 10 years.
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OBJECTIVES: (1) To compare clinical outcome and symptomatology of rheumatoid cervical myelopathy between patients managed conservatively and surgically. (2) To determine if surgical outcome has improved since the series published from this unit in 1987. (3) To examine the role of magnetic resonance imaging (MRI) in the diagnosis of cervical myelopathy. METHODS: Patients undergoing MRI of the cervical spine between 1991 and 1996 were identified. Case records were reviewed retrospectively. RESULTS: 111 patients with RA underwent 124 MRI scans. The median age at onset of cervical spine symptoms was 58 years (range 16-87) with median disease duration of 16 years (range 1-59). 18 (16%) required surgery immediately after MRI. 93 (84%) were managed conservatively, 9 of whom (10%) later required surgery. 2/7 deaths in the conservative group were directly related to cervical myelopathy. Patients requiring surgery were more likely to report paraesthesia, weakness, unsteadiness and to exhibit extensor plantar reflexes, gait disturbance, and reduced power. MRI findings did not correlate with clinical features. When compared with the 1974-82 cohort, fewer patients had severe myelopathy (Ranawat grade IIIB) before surgery (34% versus 7%). Early postoperative mortality improved from 9% to 0% and surgical complication rate fell from 50% to 22%. 89% of patients in the 1991-96 cohort reported subjective improvement in overall function. CONCLUSION: In this series surgical outcome has improved. The major factor in this more favourable outcome is probably that patients presenting with rheumatoid cervical myelopathy are now referred for surgery at an earlier stage of disease. Clinical findings correlate poorly with MRI findings, therefore clinical history should remain the key to determining the need for MRI. (+info)