Increase in vertebral body height after vertebroplasty.
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BACKGROUND AND PURPOSE: During clinical work, we have seen increases in vertebral body height associated with vertebroplasty, but our literature search revealed no reports as to how often and to what degree those increases occur. The purpose of this study was to document the frequency and degree of changes in vertebral body height after vertebroplasty. METHODS: The heights of 85 vertebral bodies in 37 patients were measured before and after vertebroplasty. In addition, one adjacent vertebral body was measured in each patient as a control. Twenty-six patients had compression fractures in the thoracic spine, and 24 patients had compression fractures in the lumbar spine. Vertebroplasty was performed with a bilateral transpedicular approach by injecting polymethylmethacrylate, under biplane fluoroscopic control. Measurements were performed on preoperative MR images and on postoperative CT sagittal reformations. Anterior, central, and posterior vertebral body height measurements were obtained in the midsagittal plane. RESULTS: The average increase in vertebral body height was 2.5 mm anteriorly, 2.7 mm centrally, and 1.4 mm posteriorly. Thirteen of 85 treated vertebrae remained unchanged. All control vertebral bodies also remained unchanged. CONCLUSION: Vertebral body height often increases during vertebroplasty. The clinical significance of increasing vertebral body height is unknown. (+info)
Topographical thickness of the epithelium and total cornea after hydrogel and PMMA contact lens wear with eye closure.
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PURPOSE: To determine changes in topographical thickness of the epithelium and total cornea after hydrogel (2-hydroxyethyl methacrylate; HEMA or soft lens) and PMMA rigid contact lens wear with eyes closed, as measured by optical coherence tomography (OCT). METHODS: Epithelial and total corneal thickness in 18 neophyte eyes was measured with OCT at intervals of 10 degrees across a 10-mm zone of the horizontal meridian of the cornea, before and after 3 hours of soft and rigid contact lens wear with the eye closed. These measurements were repeated 20 minutes after removal of the lenses. RESULTS: Lens type, time, and location were found to be significant main influences (P < 0.0001) on corneal swelling in patched eyes, by three-way ANOVA, and there was a significant three-way interaction among lens type, time, and location (F((16,272)) = 1.78, P = 0.033). However, there was no significant main effect and interaction of epithelial thickness (F((16, 272)) = 0.33, P = 0.99). Immediately after removal of the lenses, total corneal thickness in the horizontal meridian was significantly greater with both soft and PMMA lenses (P < 0.001) at each location with each lens, compared with the baseline measurements. With both lenses, the increase in actual thickness and percentage of corneal swelling at the center was greater than at each peripheral point (excluding the first 10 degrees points; P < 0.005). HEMA lenses caused greater corneal swelling than the PMMA lenses at each location immediately after removal of the lenses (P < 0.005). CONCLUSIONS: This study shows that corneal swelling is dependent on lens type and corneal location when eyes are closed, but epithelial thickness across the horizontal corneal meridian does not change during lens wear with eyes closed. OCT is an efficient method of measuring topographical corneal and epithelial thickness in response to contact lens wear. (+info)
Studies on MMA-tBB resin. I. Comparison of TBB and other initiators in the polymerization of PMMA/MMA resin.
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Polymerization characteristics of poly (methyl methacrylate)(PMMA)/(methyl methacrylate) (MMA) resin initiated by tributylborane (TBB) were compared with those by benzoyl peroxide (BPO)/N,N-dimethyl-p-toluidine and camphorquinone (CQ)/N,N-dimethylaminoethyl methacrylate from the aspects of temporal changes of residual MMA and molecular weight up to 4 weeks at 37 degrees C. Residual MMA 30 min after polymerization decreased from 8.15% for TBB resin, 8.39% for the BPO resin, and 9.19% for the CQ resin to 0.48%, 3.54%, and 6.79%, respectively, after 4 weeks. The molecular weights at 30 min and 4 weeks after polymerization were 409 x 10(3) and 247 x 10(3) for TBB resin, 297 x 10(3) and 282 x 10(3) for the BPO resin, and 267 x 10(3) and 231 x 10(3) for the CQ resin, respectively. The present results revealed that the TBB-initiated polymerization had unique and different characteristics compared with those initiated by the other common initiators: (1) The decrease in residual MMA was fast, sustained for a long time and resulted in very low value; (2) high molecular weight PMMA was formed first and then decreased with time. (+info)
Improving a self-curing dental resin by eliminating oxygen, hydroquinone and water from its curing process.
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Self-curing dental resins are always manipulated in the presence of curing inhibitory factors such as oxygen, hydroquinone, water and another contaminants such as saliva and blood. The purpose of this study was to elucidate the effects of eliminating these curing inhibitory factors on resin properties. Several clinically relevant characteristics of an experimental resin cured in the absence of inhibitory factors (purified group) were determined and compared with the resin cured conventionally (control group). The purified group showed a significantly shorter induction period and higher reaction exotherm. It also showed significantly higher tensile strength and lower strain to failure. With regard to the amount of residual monomer, fracture toughness and fatigue strength the improvements were not significant. These findings suggest that the polymerization outcomes and mechanical properties of the purified group resin can be improved in general. Dental clinicians should pay attention to the storage and curing environments while manipulating the self-curing resin. (+info)
Extending polymerization time of polymethylmethacrylate cement in percutaneous vertebroplasty with ice bath cooling.
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Currently available preparations of polymethylmethacrylate (PMMA) cement for percutaneous vertebroplasty have injectability times of 4-15 minutes. The potential for early polymerization requires procedures to be performed as fast as possible, sometimes with suboptimal results and waste of the cement. By cooling the PMMA mixture in an iced bath of sodium chloride solution, we can extend its injectability to over 2 hours and use one kit for the controlled treatment of multiple levels with successive needle placements. We have been using this technique since mid-1998, treating more than 600 vertebral bodies. (+info)
Vertebroplasty in the treatment of vertebral tumors: postprocedural outcome and quality of life.
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The results of percutaneous vertebroplasty with polymethylmethacrylate (PMMA) of vertebral metastases were evaluated by a retrospective review of a consecutive series of 21 patients, with special reference to functional outcome. Patients complained of vertebral pain in all cases. Walking was impossible for 13 patients. Ten patients presented neurological deficit. Treatment included percutaneous vertebroplasty in all patients, radiotherapy in 15 patients and neural decompression surgery in 3 patients. Mean duration of hospitalization was 14.1 days (range 2-60 days) and the mean follow-up was 5.6 months (range 1-18 months). Preprocedural pain, measured by the visual analog scale (VAS), was 9.1, decreasing to 3.2 after the procedure and 2.8 at the last follow-up visit. Morphinics were discontinued in 7 of 14 patients following discharge from hospital. Ten out of 13 (77%) patients recovered walking capacity. Neurological status improved in three out of five patients. No further vertebral compression occurred in the vertebrae treated. Overall, 81% of the patients in this study were satisfied or very satisfied with the procedure. One patient (5%) had transitory radicular neuritis after the procedure. No major complications were observed. In conclusion, percutaneous vertebroplasty with PMMA proved to be safe and beneficial, providing significant and early improvement in the functional status of patients with spinal metastasis. (+info)
Intrathecal injection of contrast medium to prevent polymethylmethacrylate leakage during percutaneous vertebroplasty.
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The major technical drawback of percutaneous vertebroplasty is the potential for neural compromise from leakage of polymethylmethaorylate into epidural or perivertebral veins. We have combined the procedure of intrathecal injection of contrast medium with vertebroplasty to better delineate spinal canal encroachment during injection when the posterior vertebral wall is compromised by myeloma. (+info)
Sacroplasty: a treatment for sacral insufficiency fractures.
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Sacral insufficiency fracture is a debilitating injury for which no active treatment is currently available. We present three consecutive cases of elderly patients with sacral insufficiency fractures whose symptoms were relieved immediately by treatment of the fractures by polymethylmethacrylate injections, a so-called sacroplasty. (+info)