| 1. |
- Abul-Kasim, Kasim, et al.
(författare)
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Reliability of Low-Radiation Dose CT in the Assessment of Screw Placement After Posterior Scoliosis Surgery, Evaluated With a New Grading System
- 2009
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Ingår i: Spine. - 0362-2436. ; 34:9, s. 941-948
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Tidskriftsartikel (refereegranskat)abstract
- Study Design. A retrospective study. Objective. To evaluate the reliability of computed tomography (CT) with low radiation dose in the assessment of implant status in patients with adolescent idiopathic scoliosis (AIS). Summary of Background Data. The use of all-pedicle screw construct in scoliosis corrective surgery continues to gain increasing popularity since their introduction 1994 although their use in the thoracic spine carries a potential risk for neurovascular complications. CT is the method widely used to evaluate screw placement. Methods. Retrospective analysis of 46 consecutive low-dose spine CT in patients with AIS after posterior corrective surgery. Status of 809 titanium screws (642 thoracic) was evaluated. The degree of interobserver and intraobserver agreements about implant status was used as an indicator of the reliability of the low-dose spine CT in the assessment of accuracy of pedicle screw insertion. A new grading system has been developed for this purpose. Five types of misplacement have been evaluated: lateral, medial, and anterior cortical perforations; end-plate perforation; and foraminal perforation. Results. The analysis has shown a substantial interobserver and intraobserver agreements (kappa: 0.69 and 0.76, respectively) in differentiating pedicle screws with acceptable placement from screws with partial or total cortical perforation. None of the examinations was subjectively classified as unreliable. Conclusion. The study has shown that low-dose spine CT is a reliable method in evaluating screw placement in patients with AIS after posterior scoliosis surgery with titanium implants, using the here proposed grading system. The new grading system of screw misplacement was feasible and in line with the general agreement about the harmlessness of misplacement with minor pedicle breach. The reliability of low-dose spine CT in evaluation of lateral and medial cortical perforations was substantial. To reduce the radiation load, the postoperative assessment of titanium implants should be performed with low-dose CT.
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| 2. |
- Albeck, Michael J, et al.
(författare)
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A controlled comparison of myelography, computed tomography, and magnetic resonance imaging in clinically suspected lumbar disc herniation
- 1995
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Ingår i: Spine. - 0362-2436. ; 20:4, s. 443-448
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN. A controlled prospective blinded study. OBJECTIVES. To compare the diagnostic power of myelography, computed tomography and magnetic resonance imaging in the diagnosis of low lumbar disc herniation. METHODS. Eighty patients with monoradicular sciatica were examined by myelography, computed tomography, and magnetic resonance imaging, and all underwent subsequent surgery. The images were evaluated twice in a blinded fashion, and the diagnostic power of the modalities was expressed by a decision-analytic regret function. RESULTS. In 57 patients (71%) a disc herniation at the expected level was disclosed at surgery. The largest amount of diagnostic information was gained from computed tomography, followed by magnetic resonance imaging and myelography. Both computed tomography and magnetic resonance imaging were significantly informative, whereas this was not the case for myelography. CONCLUSION. The results indicate that computed tomography or magnetic resonance imaging should be the first choice for imaging in patients with suspected lumbar disc herniation.
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| 3. |
- Annertz, Mårten, et al.
(författare)
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No relationship between epidural fibrosis and sciatica in the lumbar postdiscectomy syndrome. A study with contrast-enhanced magnetic resonance imaging in symptomatic and asymptomatic patients
- 1995
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Ingår i: Spine. - 0362-2436. ; 20:4, s. 449-453
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN. Symptomatic patients were retrospectively analyzed and compared with a control group from an ongoing prospective and consecutive study. OBJECTIVES. To determine the presence and extent of epidural fibrosis in patients with and without recurrent sciatic pain after previous lumbar discectomy, contrast-enhanced magnetic resonance images were evaluated and correlated with surgical findings in the symptomatic patients. Recurrent hernia and bony stenosis were ruled out as the probable causative agent, as well as any morphologic explanation other than fibrosis. SUMMARY OF BACKGROUND DATA. Repeat surgical results for patients with the lumbar postdiscectomy syndrome with epidural fibrosis alone are often unfavorable. The pathogenic role of epidural fibrosis, however, has not been established. METHODS. The magnetic resonance images of eight patients with recurrent or persistent sciatic pain after lumbar discectomy were compared with those of eight asymptomatic patients constituting a control group. All were examined with magnetic resonance imaging on a 0.3 T unit before and after intravenous injection of gadolinium-DTPA, and clinically, 6 months to 4 years after surgery. The symptomatic patients subsequently underwent reoperation. RESULTS. Fourteen patients had focal or diffuse epidural fibrosis around the nerve root and/or the thecal sac at the operated level, whereas the postoperative findings for two patients were "normal," one in the operated and one in the control group. No difference between the groups regarding mass effect or affection of the nerve roots or thecal sac was noted. At reoperation of the eight symptomatic patients, fibrosis was the only pathologic finding in all cases except one, in which surgery confirmed the normal finding on magnetic resonance imaging. Six of the eight operated patients had recurrent or persistent symptoms within a year of the reoperation. CONCLUSION. No differences regarding the presence and extent of epidural fibrosis between the symptomatic and asymptomatic patients could be demonstrated with contrast-enhanced magnetic resonance imaging. The role of epidural fibrosis as the causative agent in the lumbar postdiscectomy syndrome is questioned.
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| 4. |
- Axelsson, Paul, et al.
(författare)
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Effect of lumbar orthosis on intervertebral mobility. A roentgen stereophotogrammetric analysis
- 1992
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Ingår i: Spine. - 0362-2436. ; 17:6, s. 81-678
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Tidskriftsartikel (refereegranskat)abstract
- To determine the stabilizing effect of external lumbar supports on the intervertebral mobility in the lower lumbar spine, seven patients with a posterolateral lumbosacral fusion without internal fixation were examined by roentgen stereophotogrammetric analysis in supine and erect positions 1 month after surgery, that is, after soft tissue healing but before fusion consolidation. Each patient was examined without lumbar support, with a molded, rigid orthosis and with a canvas corset with molded, plastic posterior support. Neither of the two types of lumbar support had any stabilizing effect on the sagittal, vertical, or transverse intervertebral translations. This study using roentgen stereophotogrammetric analysis confirms that lumbosacral orthosis has effect by restricting gross motions of the trunk rather than intervertebral mobility in the lumbar spine.
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| 5. |
- Axelsson, Paul, et al.
(författare)
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Lumbar orthosis with unilateral hip immobilization. Effect on intervertebral mobility determined by roentgen stereophotogrammetric analysis
- 1993
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Ingår i: Spine. - 0362-2436. ; 18:7, s. 9-876
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Tidskriftsartikel (refereegranskat)abstract
- To determine the additional stabilizing effect of unilateral hip fixation on external lumbar supports, nine patients with a posterolateral lumbosacral fusion without internal fixation were examined by roentgen stereophotogrammetric analysis. The roentgen stereophotogrammetric analysis was performed with the patients in supine and erect positions 1 month after surgery, that is, before fusion consolidation. Each patient was examined without lumbar support and with a molded, rigid thoracolumbosacral orthosis with extension to one thigh, thus immobilizing one hip. The additional hip immobilization had no consistent or significant stabilizing effect on the sagittal, vertical, or transverse intervertebral translations in the lower lumbar spine. This study using roentgen stereophotogrammetric analysis gave no support for including hip immobilization when using lumbar orthoses after spinal fusion in patients adequately cooperating to minimize gross body motions.
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| 6. |
- Axelsson, Paul, et al.
(författare)
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Mechanics of the external fixation test in the lumbar spine. A roentgen stereophotogrammetric analysis
- 1996
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Ingår i: Spine. - 0362-2436. ; 21:3, s. 3-330
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN: By implanting tantalum indicators percutaneously during application of pedicular screws, lumbosacral mobility could be studied with roentgen stereophotogrammetric analysis in seven patients having a diagnostic external fixation test. OBJECTIVES: To determine the mechanical effects on the segmental mobility during an external fixation test of the lumbar spine. SUMMARY OF BACKGROUND DATA: External pedicular fixation test of the lumbar spine has been reported a valuable prognostic instrument in fusion for low back pain. METHODS: A Magerl external fixation device was applied in seven patients with low-grade spondylolysis-olisthesis. By using roentgen stereophotogrammetric technique, the intervertebral translations in the lumbosacral segment were determined. Each patient had three separate examinations; with the frame fixed, with the frame loosened, and without frame 6 weeks after screw removal. RESULTS: With the external frame fixed, the sagittal intervertebral translations were significantly reduced, in three cases to a level beneath the accuracy of the measuring method. One patient had the same immobilizing effect even with the frame loosened while for the others loosening of the frame meant regained mobility of the segment. CONCLUSION: The properties of the external fixator give an adequate mechanical basis for the prognostic external fixation test in lumbar fusion.
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| 7. |
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| 8. |
- Axelsson, Paul, et al.
(författare)
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The spondylolytic vertebra and its adjacent segment. Mobility measured before and after posterolateral fusion
- 1997
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Ingår i: Spine. - 0362-2436. ; 22:4, s. 7-414
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN: By using roentgen stereophotogrammetric analysis in six patients having tantalum indicators implanted at a preoperative external fixation test, the mobility in the spondylolytic lumbosacral level and its adjacent segment could be studied before fusion and during the course of postoperative fusion consolidation. OBJECTIVE: To study the mobility effects on the segment adjacent to a lumbar fusion over time from the preoperative situation until fusion healing as defined by roentgen stereophotogrammetric analysis. SUMMARY OF BACKGROUND DATA: In vitro studies indicate that the altered biomechanical situation after lumbar fusion increases the intradiscal pressure and changes the kinematics in the juxtafused segment. METHODS: Six patients with low grade spondylolysisolisthesis were scheduled for fusion of the spondylolytic lumbosacral segment after a preoperative external fixation test. The latter procedure also included implantation of tantalum markers for spinal roentgen stereophotogrammetric analysis. Each patient was examined by roentgen stereophotogrammetric analysis at four separate occasions: before fusion (2 months after removal of the external frame) and 3, 6, and 12 months after surgery. The translatory movements of the L5 vertebra in relation to sacrum and of the L4 vertebra in relation to the L5 vertebra were calculated at each examination. RESULTS: For the juxtafused L4-L5 level, increased and decreased mobility patterns could be identified. Transformation of the preoperative mobility in the lumbosacral segment to the adjacent segment during fusion consolidation was verified in two patients but was not a general phenomenon. CONCLUSION: Fusion of the lumbosacral segment can alter the kinematics of the adjacent segment, redistributing the mobility toward relative hypermobility in the juxtafused segment.
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| 9. |
- Buttle, David, et al.
(författare)
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The biochemistry of the action of chymopapain in relief of sciatica
- 1986
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Ingår i: Spine. - 0362-2436. ; 11:7, s. 688-694
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Tidskriftsartikel (refereegranskat)abstract
- A study has been made of the mechanism of action of intradiscal injections of preparations of chymopapain in the treatment of sciatica. Such preparations were found to contain at least four distinct proteins, but enzymatically active chymopapain was the component mainly responsible for releasing glycosaminoglycan from cartilaginous tissue. Previous suggestions that an electrostatic interaction between chymopapain and glycosaminoglycan is important to the action of injected enzyme were not supported by the finding that both positively and negatively charged forms of chymopapain efficiently released glycosaminoglycan from cartilaginous tissue. In contrast, cysteine alone did not cause release of glycosaminoglycan. Chymopapain was found to be inhibited efficiently by the protein inhibitors, cystatin C and low molecular weight kininogen in vitro, and the possible relevance of this finding to the efficacy and safety of chemonucleolysis is discussed.
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| 10. |
- Danielsson, Aina, 1953, et al.
(författare)
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A prospective study of brace treatment versus observation alone in adolescent idiopathic scoliosis: a follow-up mean of 16 years after maturity
- 2007
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Ingår i: Spine. - 1528-1159 .- 0362-2436. ; 32:20, s. 2198-207
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN: The Swedish patients included in the previous SRS brace study were invited to take part in a long-term follow-up. OBJECTIVE: To investigate the rate of scoliosis surgery and progression of curves from baseline as well as after maturity. SUMMARY OF BACKGROUND DATA: Brace treatment was shown to be superior to electrical muscle stimulation, as well as observation alone, in the original SRS brace study. Few other studies have shown that brace treatment is effective in the treatment of scoliosis. METHODS: Of 106 patients, 41 in Malmo (all Boston brace treatment) and 65 in Goteborg (observation alone as the intention to treat), 87% attended the follow-up, including radiography and chart review. All radiographs were (re)measured for curve size (Cobb method) by an unbiased examiner. Searching in the mandatory national database for performed surgery identified patients who had undergone surgery after maturity. RESULTS: The mean follow-up time was 16 years and the mean age at follow-up was 32 years The 2 treatment groups had equal curve size at inclusion. The curve size of patients who were treated with a brace from the start was reduced by 6 degrees during treatment, but the curve size returned to the same level during the follow-up period. No patients who were primarily braced went on to undergo surgery. In patients with observation alone as the intention to treat, 20% were braced during adolescence due to progression and another 10% underwent surgery. Seventy percent were only observed and increased by 6 degrees from inclusion until now. No patients underwent surgery after maturity. Progression was related to premenarchal status. CONCLUSION: The curves of patients with adolescent idiopathic scoliosis with a moderate or smaller size at maturity did not deteriorate beyond their original curve size at the 16-year follow-up. No patients treated primarily with a brace went on to undergo surgery, whereas 6 patients (10%) in the observation group required surgery during adolescence compared with none after maturity. Curve progression was related to immaturity.
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