Vertebroplasty in patients with severe vertebral compression fractures: a technical report.
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Vertebroplasty is a procedure in which polymethlymethacrylate (PMMA) is injected into a vertebral body compression fracture. It has been suggested that fractues greater than 65% to 70% of the original vertebral body height are too compressed to be treated successfully with this procedure. We describe six patients with severe compression fractures that were successfully treated with vertebroplasty in which the trocar was inserted in the far lateral aspect of the vertebral body, because of the typical morphology of severe compression fractures. (+info)
Percutaneous transpedicular vertebroplasty with PMMA: operative technique and early results. A prospective study for the treatment of osteoporotic compression fractures.
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Vertebroplasty-percutaneous cement augmentation of osteoporotic vertebrae is an efficient procedure for the treatment of painful vertebral fractures. From a prospectively monitored series of 70 patients with 193 augmented vertebrae for osteoporotic and metastatic lesions, we analysed a group of 17 patients suffering from back pain due to osteoporotic fractures. The reinforcement of 45 vertebral bodies in these patients led to a significant and lasting pain reduction (P < 0.01 ). The presented technique is useful, as, in one session, at least four injections can be performed when required, allowing the prophylactic reinforcement of adjacent vertebrae as well. The use of a low-viscosity polymethyl methacrylate (PMMA) in combination with a non-ionic liquid contrast dye provides a reliable and safe procedure. Extraosseous cement leakage was seen in 20% of the interventions; however, none of them had clinical sequelae. (+info)
Study of two cohorts of workers exposed to methyl methacrylate in acrylic sheet production.
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OBJECTIVES: To study mortality among 4324 workers at two United Kingdom factories, Darwen, Lancashire and Wilton, Cleveland, producing polymethyl methacrylate (PMMA) sheet. The Darwen factory is still active, but the Wilton one was closed in 1970. Also, to investigate patterns of mortality after exposure to methyl methacrylate; in particular, mortality from colon and rectal cancer. METHODS: All male employees at the Darwen factory with a record of employment in 1949-88 and all men ever employed at the Wilton factory (1949-70) were investigated. The vital status of both cohorts was ascertained on 31 December 1995. The exposure of 1526 subjects at the Darwen plant who were engaged from 1949 onwards could be characterised. The mean duration of exposure was 7.6 years at 13.2 ppm (8 hour time weighted average), although exposures in some work groups were as high as 100 ppm. It was not possible to calculate the cumulative exposure of workers first employed at the Darwen plant before 1949 or workers at the Wilton factory. RESULTS: In the Darwen cohort, 622 deaths were identified and a further 700 deaths in the Wilton cohort. Mortalities for the cohort were compared with national and local rates and expressed as standardised mortality ratios (SMRs). In the subcohort of Darwen workers with more than minimal exposure to MMA, reduced mortalities compared with national and local rates, were found for all causes (SMR 94), and colorectal cancer (SMR 92), but mortality from all cancers was slightly increased (SMR 104). No relations were found with cumulative exposure to MMA. In the subcohort of Wilton workers, mortality from all causes of death was significantly reduced (SMR 89), but mortality from all cancers (SMR 103) and colorectal cancer (SMR 124) were increased. The excess of colorectal cancer was confined to employees with less than 1 year of employment. CONCLUSION: The study provided no clear evidence that employment at the factories or exposure to MMA had adversely affected the mortalities of workers. (+info)
Long-term observations of vertebral osteoporotic fractures treated by percutaneous vertebroplasty.
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OBJECTIVE: To assess the immediate and long-term efficacy and safety of percutaneous vertebroplasty with polymethylmethacrylate (PMMA) for the treatment of refractory pain resulting from osteoporotic vertebral fractures. METHODS: A retrospective, open study of percutaneous vertebroplasty (PV) was conducted with long-term follow-up. PV with PMMA was carried out between 1990 and 1996 in 40 patients with symptomatic osteoporotic vertebral fracture(s) that had not responded to maximum medical therapy. In 1997, each patient was asked to come back to our institution for a physical and spinal X-ray examination. Efficacy was assessed by changes over time in pain on Huskisson's visual analogue scale (VAS). RESULTS: Thirty-four vertebrae treated by PV in 25 patients were evaluated with long-term follow-up. The mean duration of follow-up was 48 months (range 12-84 months). Pain assessed by the VAS significantly (P<0.05) decreased from a mean of 80 mm+/-16 (S.D.) before PV to 37+/-24 mm after 1 month and 34+/-28 mm at the time of maximal follow-up. There was no severe complication related to this treatment, and no progression of vertebral deformity in any of the injected vertebrae. However, there was a slight but significantly increased risk of vertebral fracture in the vicinity of a cemented vertebra (odds ratio 2.27, 95% confidence interval 1.1-4.56). The odds ratio of a vertebral fracture in the vicinity of an uncemented fractured vertebra was 1.44 (0.82-2.55). CONCLUSION: PV appears to be a safe and useful procedure for the treatment of focal back pain secondary to osteoporotic vertebral fracture when conservative treatment has failed. (+info)
Influence of intraocular lens material and design on postoperative intracapsular cellular reactivity.
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PURPOSE: To evaluate the influence of intraocular lens (IOL) material and design on the outcome of postoperative lens epithelial cell proliferation within the capsular bag after cataract surgery. METHODS: A total of 5,079 human globes containing rigid and foldable posterior chamber IOL styles commonly implanted in the United States (n = 8) were analyzed in this study. Each globe, fixated in 10% formalin, was sectioned at the equator and analyzed using the Miyake-Apple posterior technique. The study consisted of 3 parts: First, to evaluate posterior capsule opacification (PCO); the Nd:YAG laser posterior capsulotomy rate (%) was documented and plotted on a monthly basis, creating a computerized trend line for each IOL style. Second, to evaluate anterior capsule opacification (ACO); 460 globes were processed for histologic examination. Anterior capsule fibrosis was scored from 0 to III, according to the thickness of proliferative tissue/cells on the inner surface of the anterior capsule at the capsulorhexis margin. Third, interlenticular opacification (ILO) was studied by analysis of 3 pairs of acrylic piggyback lenses that had been explanted because of opacification between their optics. Each IOL pair was processed for histologic examination, and scanning electron microscopy was performed on 1 of the lenses. RESULTS: In the first study, relatively higher Nd:YAG laser posterior capsulotomy rates (19.1% to 32.8%) were noted with the 4 oldest IOL designs in this study (2 foldable lenses, 1 3-piece polymethyl methacrylate [PMMA] design, and 1 single-piece all-PMMA design). Four modern lenses, 1 acrylic lens, and 3 silicone foldable IOL designs had Nd:YAG rates ranging from 1.3% to 14.6% (P < .0001). In the second study, mean ACO scores were highest with silicone-plate lenses (1.77 +/- 0.86 and 1.28 +/- 0.77). The lowest mean score was observed with the acrylic lens (0.51 +/- 0.52; P < .0001). In study 3, the analyses of the 3 pairs of explanted acrylic piggyback lenses showed that the opacification between them (ILO) may have different forms. CONCLUSIONS: Control of postoperative intracapsular cellular proliferation is important in avoiding 3 significant clinical complications. Postoperative lens epithelial cell proliferation is involved in the pathogenesis of PCO, ACO, and ILO, the latter being a newly described form of opacification within the capsular bag related to piggyback IOL implantation. IOL material and design are important factors influencing the outcome of these complications. (+info)
Addition of antibacterial agents to MMA-TBB dentin bonding systems--influence on tensile bond strength and antibacterial effect.
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To produce a bonding system which has both high bond strength and antibacterial properties, an antibacterial agent (vancomycin: VCM or metronidazol: MN) was added to the PMMA powder of 4-META/MMA-TBB resin (CB). The influence of the addition of an antibacterial agent on tensile bond strength to dentin and the antibacterial effect were investigated in this study. Forty-seven freshly extracted bovine first or second incisors were used to measure the tensile bond strength to dentin. The bond strengths to bovine dentin were not significantly decreased by addition of VCM (1%, 2%, 5%), or MN (1%) to CB (p < 0.05). The antibacterial effect of CB containing antibacterial agent on six strains of bacteria was investigated by the agar plate diffusion method, analyzing the appearance of the inhibition zone around a resin disk following anaerobic culturing. The resin disks containing VCM showed antibacterial effects on all of the strains examined; the widths of the inhibition zones were 4-15 mm. The resin disks containing MN showed antibacterial effects on three strains; the widths of the inhibition zones were 0-4 mm. It was thus possible to produce a bonding system with both antibacterial effect and high tensile bond strength by addition of VCM to PMMA powder. (+info)
Inflammatory responses of human primary macrophages to particulate bone cements in vitro.
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We have investigated whether the particle-stimulated release of inflammatory cytokines from human primary macrophages in vitro was dependent upon the type of bone cement used. Particles of clinically relevant size were produced from Palacos R without radio-opacifier, Palacos R with BaSO4, Palacos R with ZrO2 and from CMW3 which contains BaSO4. All four preparations produced significantly greater release of tumour necrosis factor alpha, interleukin-6 and interleukin-1 beta than a negative control but there were no significant differences between them. The differences in the ability to stimulate bone resorption and in clinical performance between proprietary bone cements previously recorded are not explained by the release of the cytokines most commonly implicated in osteolysis. (+info)
Effect of PMMA particles and movement on an implant interface in a canine model.
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The pathogenesis of aseptic loosening of total joint prostheses is not clearly understood. Two features are associated with loosened prostheses, namely, particulate debris and movement of the implant. While numerous studies have evaluated the cellular response to particulate biomaterials, few have investigated the influence of movement of the implant on the biological response to particles. Our aim was therefore to test the hypothesis that excessive mechanical stimulation of the periprosthetic tissues induces an inflammatory response and that the addition of particulate biomaterials intensifies this. We allocated 66 adult Beagle dogs to four groups as follows: stable implants with (I) and without (II) particulate polymethylmethacrylate (PMMA) and moving implants with (III) and without (IV) particulate PMMA. They were then evaluated at 2, 4, 6, 12 and 24 weeks. The stable implants were well tolerated and a thin, fibrous membrane of connective tissue was observed. There was evidence of positive staining in some cells for interleukin-6 (IL-6). Addition of particulate PMMA around the stable implants resulted in an increase in the fibroblastic response and positive staining for IL-6 and tumour necrosis factor-alpha (TNF-alpha). By contrast, movement of the implant resulted in an immediate inflammatory response characterised by large numbers of histiocytes and cytokine staining for IL-1beta, TNF-alpha and IL-6. Introduction of particulate PMMA aggravated this response. Animals with particulate PMMA and movement of the implant have an intense inflammatory response associated with accelerated bone loss. Our results indicate that the initiation of the inflammatory response to biomaterial particles was much slower than that to gross mechanical instability. Furthermore, when there was both particulate debris and movement, there was an amplification of the adverse tissue response as evidenced by the presence of osteolysis and increases in the presence of inflammatory cells and their associated cytokines. (+info)