Determining the sagittal dimensions of the canal of the cervical spine. The reliability of ratios of anatomical measurements.
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The ratio of the sagittal diameter of the cervical canal to the corresponding diameter of the vertebral body has been described as a reliable means for assessing stenosis of the canal and detecting those at risk of cervical neuropraxia. The use of ratio techniques has the advantage of avoiding variation in magnification when direct measurements are made from plain radiographs. We examined the reliability of this method using plain lateral radiographs of unknown magnification and CT scans. We also assessed other possible ratios of anatomical measurements as a guide to the diameter of the canal. Our findings showed a poor correlation between the true diameter of the canal and the ratio of its sagittal diameter to that of the vertebral body. No other more reliable ratio was identified. The variability in anatomical morphology means that the use of ratios from anatomical measurements within the cervical spine is not reliable in determining the true diameter of the cervical canal. (+info)
The assessment of appropriate indications for laminectomy.
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We have developed criteria to determine the appropriate indications for lumbar laminectomy, using the standard procedure developed at the RAND corporation and the University of California at Los Angeles (RAND-UCLA). A panel of five surgeons and four physicians individually assessed 1000 hypothetical cases of sciatica, back pain only, symptoms of spinal stenosis, spondylolisthesis, miscellaneous indications or the need for repeat laminectomy. For the first round each member of the panel used a scale ranging from 1 (extremely inappropriate) to 9 (extremely appropriate). After discussion and condensation of the results into three categories laminectomy was considered appropriate in 11% of the 1000 theoretical scenarios, equivocal in 26% and inappropriate in 63%. There was some variation between the six categories of malalignment, but full agreement in 64% of the hypothetical cases. We applied these criteria retrospectively to the records of 196 patients who had had surgical treatment for herniated discs in one Swiss University hospital. We found that 48% of the operations were for appropriate indications, 29% for equivocal reasons and that 23% were inappropriate. The RAND-UCLA method is a feasible, useful and coherent approach to the study of the indications for laminectomy and related procedures, providing a number of important insights. Our conclusions now require validation by carefully designed prospective clinical trials, such as those which are used for new medical techniques. (+info)
Surgical treatment of lumbar canal stenosis in the elderly.
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The effectiveness of spinal surgery for lumbar canal stenosis was investigated in the elderly. 164 patients with lumbar canal stenosis were surgically treated over 8 years. 125 patients were followed up by letter questionnaire. The outcome and patient satisfaction with the surgical procedures were compared between the 73 younger patients (< or = 64 years of age) and the 52 elderly patients (> or = 65 years of age). Intermittent claudication was satisfactorily improved in both the younger and the elderly groups. Both simple laminectomy and laminectomy with fusion could equally improve the symptoms of intermittent claudication. Although statistically not significant, there was tendency that laminectomy plus fusion effectively improved the symptoms of back pain and leg pain in both groups. 75% of the younger patients and 67% of the elderly were pleased with the outcome. The present study shows that elderly patients with lumbar canal stenosis should be actively considered for surgical treatment. (+info)
MR imaging of a hemorrhagic and granulomatous cyst of the ligamentum flavum with pathologic correlation.
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Cysts of the ligamentum flavum are uncommon causes of neurologic signs and symptoms and usually are seen in persons over 50 years of age. We report a case of an epidural cyst located in the ligamentum flavum, which contributed to spinal stenosis in a 30-year-old man. Radiologic features were similar to those of a synovial cyst, but synovium was not identified histologically. The imaging and pathologic features were unusual, including hemorrhage and a fibrohistiocytic reaction with giant cells. (+info)
Histology of the ligamentum flavum in patients with degenerative lumbar spinal stenosis.
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The degree of calcification as well as the structural changes of the elastic fibres in the ligamentum flavum in patients with degenerative lumbar spinal stenosis were evaluated and the results were compared to those of patients without spinal stenosis. In 21 patients (13 male, 8 female) with lumbar spinal stenosis the ligamentum flavum was removed, histologically processed and stained. The calcification, the elastic/collagenous fibre ratio as well as the configuration of the fibres were evaluated with an image analyzing computer. As a control group, 20 ligaments of 10 human corpses were processed in the same way. The results were statistically analysed using the Mann-Whitney-Wilcoxon test (alpha = 0.05) and the t-test (alpha = 0.05). Nearly all the ligaments of patients with lumbar spinal stenosis were calcified (average 0.17%, maximum 3.8%) and showed relevant fibrosis with decreased elastic/collagenous fibre ratio. There was a significant correlation between age and histological changes (P<0.05). In the control group we only found minimal calcification in 3 of 20 segments (average 0.015%). No relevant fibrosis was found and the configuration of elastic fibres showed no pathologic changes. The results of this study illustrate the important role of histological changes of the ligamentum flavum for the aetiology of lumbar spinal stenosis. (+info)
The placement of lumbar pedicle screws using computerised stereotactic guidance.
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Computer-assisted frameless stereotactic image guidance allows precise preoperative planning and intraoperative localisation of the image. It has been developed and tested in the laboratory. We evaluated the efficacy, clinical results and complications of placement of a pedicle screw in the lumbar spine using this technique. A total of 62 patients (28 men, 34 women) had lumbar decompression and spinal fusion with segmental pedicle screws. Postoperative CT scans were taken of 35 patients to investigate the placement of 330 screws. None showed penetration of the medial or inferior wall of a pedicle. Registration was carried out 66 times. The number of fiducial points used on each registration averaged 5.8 (4 to 7) The mean registration error was 0.75 mm (0.32 to 1.72). This technique provides a safe and reliable guide for placement of transpedicular screws in the lumbar spine. (+info)
Motor conduction alterations in patients with lumbar spinal stenosis following the onset of neurogenic claudication.
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The pathogenesis of neurogenic claudication is thought to lie in relative ischemia of cauda equina roots during exercise. In this study we will evaluate the effect of the transient ischemia brought on by exercise on motor conduction in patients suffering from lumbar spinal stenosis (LSS). We will also evaluate the sensitivity of motor evoked potentials (MEPs) in detecting motor conduction abnormalities before and after the onset of neurogenic claudication. Thirty patients with LSS and 19 healthy volunteers were enrolled in the study. All LSS patients had a history of neurogenic claudication and the diagnosis was confirmed with a CT myelogram. Both groups underwent a complete electrophysiological evaluation of the lower extremities. The motor evoked potential latency time (MEPLT) and the peripheral motor conduction time (PMCT) were measured. The subjects were asked to walk on a flat surface until their symptoms were reproduced. A new set of electrophysiological tests was then performed. Exercise did not produce claudication in any of the control group subjects. Twenty-seven patients did have claudication. The pre-exercise MEPLT and nerve conduction studies in the control group fell within the normal range. In the patient group, 19 patients had increased baseline values for MEPLT to at least one muscle. There was a significant difference between the MEPLT and the PMCT values measured before and after exercise in the patients with signs of neurological deficit. This difference was not found to be significant in patients without neurological deficits (t-test P < 0. 05). It may be concluded that exercise increases the sensitivity of MEPs in detecting the roots under functional compression in LSS. (+info)
Medical versus surgical treatment for low back pain: evidence and clinical practice.
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CONTEXT: Although low back pain is one of the most common health problems, it is still difficult to choose between surgical and medical treatment. OBJECTIVE: To examine the evidence of the efficacy of surgical and medical treatment of the two most common indications for spinal surgery for low back pain--lumbar disc herniation and spinal stenosis--and to assess geographic variation in the use of surgery for these conditions in the United States. METHODS: The MEDLINE database (1966-1999) was searched for all studies that compared surgical and medical treatments for low back pain. Data from the Health Care Financing Administration were used to examine geographic variation in spinal surgery rates for patients enrolled in Medicare (1996-1997). RESULTS: Eight observational studies and one randomized clinical trial were identified. In general, these studies suggest better short-term outcomes (e.g., functional status and employability) with surgery than with medical approaches, but they indicate that long-term results are similar with both types of treatment. Methodologic flaws in the observational studies, particularly selection bias, preclude definitive conclusions about relative efficacy. In 1996 and 1997, more than 98,000 Medicare enrollees had surgery for disc herniation or spinal stenosis. Among hospital referral regions, rates of surgery for disc herniation varied 8-fold, from 0.24 to 1.96 per 1000 Medicare enrollees, and rates of surgery for spinal stenosis varied 12-fold, from 0.29 to 3.34 per 1000 Medicare enrollees. CONCLUSIONS: The literature comparing the efficacy of surgical and medical treatment for low back pain is limited. Not surprisingly, the use of surgery for low back pain varies widely across the United States. To establish clinical consensus, we need better evidence about the efficacy of surgery. (+info)