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OBJECTIVE: Sacroplasty, or the injection of percutaneous polymethyl methacrylate into a sacral insufficiency fracture, has been previously described using needle placement in the short axis of the sacrum. We describe a new technique of needle placement along the long axis of the sacrum. CONCLUSION: This approach is easier to perform and results in improved cement distribution along the length of the sacral ala.
Acetal resins have been used as an alternative denture base and clasp material recently. The aim of this study was to compare water sorption and water solubility of pink and white acetal resins as compared to a heat-polymerized polymethyl methacrylate resin (PMMA). The tests were performed in accordance with International Standards Organization specification No: 1567. Pink acetal resin showed significantly lower water sorption than heat-polymerized acrylic resin and white acetal resin. PMMA showed significantly higher solubility than pink and white acetal resin. Water sorption and solubility of PMMA, pink and white acetal resins were within the ISO specification limit.
During cemented joint arthroplasties, it is necessary to monitor the hardening of the cement to know when it is soft enough to allow insertion of the prosthesis but viscous enough to maintain bone interlock. Most often, a small piece of cement is left out and checked for hardening. These cement pieces are exposed to different fates, which include being held in the hand, held between fingers and kneaded, and left on the instrument table. The value of any of these techniques for predicting the cement's hardening has not been investigated formally. During 9 total hip arthroplasties, polymethyl methacrylate bone-cement was used in cementing the femoral component. Three 1-cm(3) samples collected from each operation site were exposed to the aforementioned 3 different conditions. The fingertip-held and kneaded cement specimens most closely predicted the time to setting of the cement mantle at the operation site.
We show that the morphology of polyethylene oxide crystallization in thin films can be tuned to obtain circular spherulites, seaweed and symmetric dendrites, and fractal aggregation forms through the addition of clay particles and the amorphous polymer, polymethyl methacrylate. The thin-film polymer crystallization patterns are compared to a two-dimensional phase field model of dendritic growth in Ni/Cu alloys with a variable surface tension anisotropy epsilon. Some aspects of polymer crystallization patterns can be understood from the phase field calculations, but a more general model is required to describe the full range of observed patterns.
Snowflake degeneration of intraocular lenses is a recently recognized late postoperative complication of cataract surgery. All known cases reported to date in the literature have involved polymethyl methacrylate (PMMA) lens optic material. Reported herein is an atypical variant of snowflake degeneration of a PMMA posterior chamber intraocular lens in an 81-year-old woman, 7 years post implantation. The aetiology of the atypical late opacification of the intraocular lens is this case is unclear, and no clinical risk factors appear to have been identified.
Microspheres of polymethyl-methacrylate (PMMA) are exciting new soft-tissue fillers that are becoming increasing popular for facial rejuvenation. Some reports of side effects of this procedure are basically in respect to dermal reaction, with late-onset granulomatous lesion with giant cells and vacuoles. We report blindness and total ophthalmoplegia after PMMA injection into glabellar area in a healthy woman and review the literature.
PURPOSE: Prospective evaluation of vertebroplasty for osteoporotic compression fractures concerning pain reduction, demand of analgesics and quality of life. MATERIAL AND METHODS: In 26 consecutive patients, 50 vertebral fractures were treated by percutaneous vertebroplasty under fluoroscopic (n = 44) or combined fluoroscopic/CT guidance (n = 6). Prospective follow-up was performed after 6 (for 50 vertebral fractures) and 12 months (for 27 vertebral fractures). Visual analogue scale (VAS) and numeric rating scale (NRS) was applied for the assessment of pain. Subjective quality of life and analgesics demand was documented semi-quantitatively. RESULTS: Mean interval from the beginning of pain symptoms to therapy was 8.5 weeks. Vertebroplasty was technically successful in all evaluated patients. Pain severity decreased from 10 (defined at baseline as initial pain score) to 2.8 after 6 months and 2.7 after 12 months. Subjective quality of life was reported as very well, well or improved in 92 % (n = 26 after 6 months) or 100 % (n = 13 after 12 months). No need for additional analgesic therapy was observed in 69.3 % (n = 26) after 6 months and 61.5 % (n = 13) after 12 months. Eight newly developed vertebral fractures were observed during follow-up, with 5 fractures directly adjacent to previously treated vertebrae. Leakage of polymethyl methacrylate (PMMA) into the intervertebral space or spinal canal was observed in 22 % and 20 % respectively (n = 50 vertebrae) . No neurologic deterioration or complications requiring surgery were observed. CONCLUSION: Vertebroplasty is a successful therapeutic approach for the treatment of osteoporotic vertebral fractures. Persistent improvement of clinical symptoms was shown at follow-up after 6 and 12 months.
STUDY DESIGN: We postulate that osteoplasty of osteolytic metastases of the pelvic region performed by computed tomography (CT)-guided insertion of Kirschner wires into the lesions is effective and more feasible. OBJECTIVE: To determine whether osteoplasty of osteolytic metastases of the pelvic region can be performed by a more feasible lesion access, increasing patient compliance and reducing patient radiation exposure. SUMMARY OF BACKGROUND DATA: Treatment of osteolytic bone metastases is palliative and relies mainly on the elimination of pain. When pain is medically intractable, this can be effectively treated by osteoplasty. MATERIALS AND METHODS: A 61-year-old man with medically intractable pain from osteolytic lesions of the sacral ala and left iliac alum from pulmonary adenocarcinoma underwent osteoplasty. The lesions were accessed using Kirschner wires under CT guidance. Subsequently, under high-resolution fluoroscopic guidance, 13-G biopsy needles were advanced coaxially over the Kirschner wires and polymethyl methacrylate (PMMA) was injected into the lesions. RESULTS: No peri-procedural complications were observed. The patient experienced an immediate and substantial pain relief that was persistent during a 4-month follow-up. CONCLUSIONS: This technique is safe and effective and requires fewer CT scans, thus reducing the patient's radiation exposure. The shorter procedure correlates to a better patient tolerance.
The infinite dilution weight fraction activity coefficient, omega 1 infinity, and Flory-Huggins interaction parameter, chi, have been determined for systems of polydimethylsiloxane (PDMS)/solvents and polymethyl-methacrylate (PMMA)/solvents by using gas chromatography from 58 degrees C to 180 degrees C. The solvents include styrene, acetone, ethyl ether, methanol, ethanol, acetic acid, trichloromethane, tetrahydrofuran and ethyl acetate in PDMS/solvent systems and n-hexane, n-heptane, cyclohexane, benzene, toluene, ethyl benzene, styrene, acetone, ethyl ether, methanol, ethanol, methyl methacrylate(MMA), trichloromethane, tetrahydrofuran and ethyl acetate in the PMMA/solvent systems. The results showed that omega 1 infinity and chi were decreased with the increase of temperature in the range from 58 degrees C to 180 degrees C. The study showed that UNIFAC and UNIFAC-FV models could not all be used to estimate omega 1 infinity of the solvents in PMMA/solvent systems. Therefore, UNIFAC and UNIFAC-FV models must be corrected or other models must be used.
STATEMENT OF PROBLEM: Microleakage between resilient liner and denture base resins is a significant clinical problem, often responsible for debonding of the resilient liner from the denture base resin. PURPOSE: This study investigated the effect of 2 surface treatments, airborne-particle abrasion (APA) and wetting with methyl methacrylate monomer (MMA), on microleakage between a silicone-based resilient liner and denture base resin using a gamma camera imaging technique. MATERIAL AND METHODS: Thirty-three specimens, each having 2 plates measuring 40 x 40 x 2 mm, were prepared by packing and processing an acrylic denture base resin (QC-20) into square plates following manufacturer's instructions. Specimens were divided into 3 groups (n=11) as APA-, MMA-, and control-treatment groups. For the APA group, the inner surfaces of both plates were airborne-particle abraded with 250-microm Al 2 O 3 particles and, for the MMA group, surfaces were treated with monomer (QC-20). Control specimens were not surface treated. Following application of an adhesive (Ufi Gel P-specific), a silicone lining material (Ufi Gel P) was prepared and applied to the inner surfaces of all 33 specimens. Eleven size-matched polymethyl methacrylate (PMMA) specimen blocks (40 x 40 x 6 mm) were prepared to calculate the level of residual radioactivity for the denture base itself, the entire outer surface count (OSC). All specimens and PMMA blocks were immersed in a radioactive solution (thallium-201 chloride) for 24 hours. Specimen activities (gamma-ray cts/sec, representing thallium-201 concentration) were then measured using a high-resolution gamma camera. The amount of OSC-subtracted total specimen counts was a direct indicator of the quantity of inward diffusing tracer. The subtracted values were analyzed using a 1-way analysis of variance (ANOVA) and Bonferroni multiple comparison tests (alpha=.05). RESULTS: OSC levels averaged 754 +/- 110 gamma-ray cts/sec. OSC-subtracted APA, control, and MMA values were 5,546 +/- 1,534, 3,392 +/- 738, and 1,405 +/- 392 gamma-ray cts/sec, respectively. All 3 groups were significantly different ( P <.05) from each other. Surface wetting with MMA showed the lowest microleakage values among all specimen groups. CONCLUSION: In terms of microleakage, surface treatment with MMA monomer preceding the adhesive application demonstrated lower values than adhesive application alone. APA pretreatment resulted in 4 times the microleakage found in MMA-treated specimens, and 1.5 times the microleakage of the untreated control. None of the surface pretreatments completely prevented microleakage. Microleakage between the silicone-based resilient liner and denture base resin can be quantitatively determined using the gamma camera imaging technique.
The aim of this work was to determine energy dependence characteristics in terms of values of the personal dose equivalent, HP(10). The following types of thermoluminescent detectors (TLDs) were investigated: (a) two new types based on lithium borate, Li2B4O7:Cu,In and Li2B4O7:Cu,In,Ag; (b) two types based on the highly sensitive material LiF:Mg,Cu,P, TLD-700H and GR 200A; (c) two well-known types of LiF:Mg,Ti detector, TLD-100 and TLD-700 and (d) highly sensitive Al2O3:C detectors. TLDs previously calibrated with 137Cs gamma rays were simultaneously irradiated with X ray beams in the range of mean energies between 33 and 116 keV. The irradiations were performed with detectors in polymethyl methacrylate (PMMA) holders placed on a 30 cm x 30 cm x 15 cm water phantom with PMMA walls (ISO phantom). Measured energy responses were compared with calculated data for HP(10) values. The results confirmed the satisfactory tissue equivalent characteristics of all investigated TLDs except Al2O3:C, which (due to its large energy dependence) is suitable for personal dosimetry only with an appropriate filter.
The image quality (IQ) evaluation of a charge-coupled device (CCD)-based digital angiography system was assessed with respect to modulation transfer function and noise power spectrum. These values were used to calculate the system's frequency-dependent detective quantum efficiency (DQE). The X-ray image detector was an image intensifier (II) lens coupled to a CCD camera. Two measurement setups were used. Setup A is standard IQ assessment, while Setup B more closely represented clinical conditions (polymethyl methacrylate (PMMA) of varying thickness placed between the X-ray tube and II, with test object positioned between PMMA slices 30 cm from the II). Exposure parameters varied according to automatic brightness control settings. Setup B included X-ray radiation scattered by the patient-PMMA. A clinical DQE, describing the transmission of the input signal-to-noise ratio associated with both primary and secondary X-ray spectra, was defined.
The experiment makes C60 composite material by mixing up C60 and polymethyl methacrylate. Then three minor studies are conducted: (1) Studying the relation of refractivity of the material with the change in temperature. (2) Studying the different change in refractivity with different amount of C60 in the composite material. (3) Studying the change in refractivity of the material radiated with ultraviolet radiation. A comparison is made between the above three cases. The result shows that: under different circumstances, the change in refractivity with the change of temperature differ.
Separation of sodium dodecyl sulfate (SDS)-protein complexes is difficult on plastic microchips due to protein adsorption onto the wall. In this paper, we elucidated the reasons for the difficulties in separating SDS-protein complexes on plastic microchips, and we then demonstrated an effective method for separating proteins using polymethyl methacrylate (PMMA) microchips. Separation difficulties were found to be dependent on adsorption of SDS onto the hydrophobic surface of the channel, by which cathodic electroosmotic flow (EOF; reversed flow) was generated. Our developed method effectively utilized the reversed flow from this cathodic EOF as a driving force for sample proteins using permanently uncoated but dynamic SDS-coated PMMA microchips. High-speed (6 s) separation of proteins and peptides up to 116 kDa was successfully achieved using this system.
Cholesterol and HIgG adsorbed from human plasma obtained from a hypercholesterolemic patient, onto protein A-immobilized polymethyl-methacrylate uniform microbeads carrying different amounts of protein A (0.264-1.682 mg protein A/g PMMA, or 0.66-4.2 mg protein A/m2 PMMA) were investigated in batchwise experiments. There was no interaction between protein A molecules and cholesterol when cholesterol aqueous solutions were used. However, there was significant cholesterol and HIgG adsorption from the plasma obtained from a patient with hypercholesterolemia. The maximum amounts of cholesterol and HIgG adsorbed were 3.96 micromol cholesterol/g PMMA (5.4 mg cholesterol/g PMMA) and 0.242 micromol IgG/g PMMA (35.4 mg IgG/g PMMA).
The use of polymethyl methacrylate has revolutionized surgical technique in total joint arthroplasty. In addition, in an effort to reduce the rate of infections as well as to treat active infections, the practice of adding powdered antibiotics to the cement has become commonplace. A simple and efficient technique of mixing antibiotic powder into cement that creates a uniform distribution of antibiotic is introduced. In addition, this process reduces the presence of "antibiotic voids," which, if present can alter the physical properties of the cement itself.
The authors' report a case of a 26-year-old female. In 1996, and 1997 she underwent cosmetic lip augmentations (polymethyl methacrylate and silicone). After a six-year symptom free period sudden swelling of the lips developed and red-brown papules and subcutaneous nodules appeared in the scars of various body parts ( permanent make-up, tattoos, umbilical piercing). The clinical features, radiological signs and histology proved the diagnosis of systemic sarcoidosis. Systemic corticosteroid treatment was introduced. After 4 months of treatment the pulmonary and clinical symptoms showed regression. To be able to suspend the systemic treatment the silicone implant was removed.
Management of an infected hip prosthesis typically requires that all associated cement be removed. In the absence of gross mantle loosening, the surgeon frequently resorts to intraoperative radiographs to assess the completeness of removal. For this reason, we undertook a study to determine limits of detection of retained cement by routine radiography. Polymethyl methacrylate bone-cement beads (Simplex-P; Stryker-Howmedica-Osteonics, Allendale, NJ) were fashioned into graduated sizes and placed within cadaver medullary canals using 2 different methods. Standard radiographic images were obtained. Individually and independently, we viewed these images and proposed the limit of resolution to be 2.4 to 3.2 mm. It is difficult to remove all cement based on radiographs alone. These results suggest a need to use techniques that permit visualization of the canal to ensure adequate cement removal.