The breakup time was 22 minutes for the dextran riboflavin film, 32 minutes for methylcellulose, and 90 seconds for the hypoosnnolar solution.
CONCLUSION: Results indicate that the cornea including the riboflavin film can be considered a composite 2-compartment system and that the riboflavin film is an integral part of the CXL procedure and important in achieving the correct stromal and endothelial UVA irradiance.”
“Study
Design. Retrospective retrieval analysis.
Objective. To evaluate wear, deformation and biodegradation within retrieved polycarbonate urethane (PCU) components of Dynesys systems.
Summary of Background Data. The Dynesys Dynamic Stabilization System (Zimmer Spine) consists of pedicle screws (Ti alloy), polycarbonate urethane (PCU) spacers, and a polyethylene-terephthalate cord. Methods. Seventeen retrieved selleck screening library (mean implantation: 2.5 years, range: 0.7-7.0 years) and 2 exemplar implant systems were available. Reasons ZD1839 ic50 for revision were persistent pain (16/17), infection (1/17), and/or screw loosening (11/17), with 1/17 case of implant
migration. Optical microscopy, microCT, and scanning electron microscopy were conducted to evaluate PCU spacer wear and deformation. Attenuated total reflectance Fourier transform infrared spectroscopy was used to assess spacer surface chemical composition.
Results. Retrieved spacer components exhibited permanent bending deformation (mean: 4.3, range: 0.0 degrees-15.8 degrees). We observed evidence of PCU spacer contact with pedicle screws, cords, and surrounding bony structures (74/75, 69/75, and 51/75 spacers, respectively). Relatively infrequent damage modes included PCU fracture (1/75 spacers) or cracking (2/75 spacers), as well as pedicle screw fracture
(3/103 screws). PCU degradation products were identified in 10/75 spacers, which represented retrievals having significantly longer implantation times (mean: 4.3 years, range: 1.0-7.0 years). Of these spacers, 8/10 had degradation peaks identified along the side of the spacer where the material would have been in contact with bodily fluid.
Conclusion. AZD7762 solubility dmso PCU spacers from retrieved Dynesys systems exhibited permanent deformation, focal regions of in vivo wear and surface damage. Chemical changes associated with PCU biodegradation were associated with longer-term retrievals. The most frequently observed complication was pedicle screw loosening, with 3 incidences of screw breakage in 2 patients. These retrieval data provide a crucial basis for developing in vitro tests to simulate in vivo damage and degradation of posterior dynamic motion preservation implants. Longer-term retrievals, as well as retrievals that include more recent design features (e. g., HA coating), will be useful to provide a greater context for the clinical implications of our short-term observations.”
“Polyurethane (PU)-clay nanocomposite coatings were prepared by a sonication method.