ABSTRACT
The interaction of molecules with titanium oxide substrates may lead to substantial modifications of their optical properties, in particular a red shift of the absorption spectrum compared to that of bare titania. In the present paper we discuss the role of the interface between two molecules, catechol and dopamine, with gas-phase (TiO2)N clusters (N = 2, 4, 6). We studied, for the interface, the bidentate modes (the molecule bonded to two Ti sites via its two oxygen sites), which was the most energetically favorable, followed by the chelated modes (the molecule bonded to one Ti site via its two oxygen sites), and the monodentate mode (the molecule bonded to one Ti site via one oxygen site). The absorption spectra were calculated with time-dependent functional-theory with CAM-B3LYP for the description of charge-transfer excitations. We observe a red shift of the molecule/cluster systems with respect to the molecules and clusters alone. Moreover, the chelated mode was found to present bands at lower energies than the other modes, making it the most interesting mode to tune the absorption edge of these systems.
ABSTRACT
INTRODUCTION: Computer image guidance is one of the most significant technologic advancements in the spine surgery, because preoperative or intraoperative images can be used for multiplanar, three-dimensional intraoperative navigation. MATERIAL AND METHODS: We performed a prospective clinical study to assess the accuracy of pedicle screw insertion using an optoelectronic navigation system (SurgiGATE Spine 2.1 Medivision). The study population included 29 patients with diverse disorders of the thoraco- lumbar spine (degenerative 54%, spondylolisthesis 21%, fractures 14%, scoliosis 7% and spondylodiscitis 4%). One patient was excluded from the study because problems with the specific instruments or the computer system. Pre and post-operative axial computed tomography images were obtained for each patient and analyzed by two independent radiologists to placement accuracy. The correct location was defined accord to Heary scale in 5 grades. RESULTS: 163 image-guided thoraco-lumbar pedicle screws were placed 29 in the thoracolumbar spine and 134 in the lumbosacral spine. We achieved a completely intraosseous placement (Grade I) in 99.4% of lumbosacral spine screws and 100% of thoracolumbar spine screws. Only one misplaced screw (Grade III) in the pedicle of L III in the concavity of a scoliosis was reported. No implant related complications were noted. CONCLUSIONS: The low rate of misplaced screws in this prospective study compares favorably with previously published results. Our initial results indicate that Image-guided spinal surgery is a safe technique which improves surgical performance during posterior transpedicle stabilization.
Subject(s)
Lumbar Vertebrae , Thoracic Vertebrae , Bone Screws , Female , Humans , Intraoperative Period , Lumbar Vertebrae/diagnostic imaging , Lumbar Vertebrae/surgery , Male , Prospective Studies , Radiography , Thoracic Vertebrae/diagnostic imaging , Thoracic Vertebrae/surgery , Treatment OutcomeABSTRACT
Introducción. La cirugía guiada por imagen es uno de los más importantes avances tecnológicos dentro de la cirugía del Raquis ya que permite al cirujano realizar una navegación multiplanar tridimensional en tiempo real en el interior de una vértebra. Material y métodos. Realizamos un estudio clínico prospectivo no randomizado sobre la fiabilidad en la colocación de tornillos pediculares mediante un sistema de navegación optoelectrónico (SurgiGATE Spine 2.1 Medivision). Se estudiaron veintinueve pacientes intervenidos por diferentes patologías en columna toracolumbar incluyendo: degenerativas (54%), espondilolistesis(21%), fracturas (14%), escoliosis (7%) y espondilodiscitis(4%). Un paciente fue eliminado del estudiodebido a un fallo técnico en el equipo de navegación.Se obtuvieron imágenes de TC pre y postoperatorias de cada paciente y éstas fueron evaluadas por dos neurorradiólogos independientes. La colocación correcta se definió de acuerdo a la escala de Heary en 5 grados.Resultados. Se colocaron 163 tornillos, 29 en la columnatoracolumbar y 134 en la columna lumbosacra.Hemos conseguido una colocación totalmente intraósea(Grado I) en el 99,4% de tornillos en la columnalumbosacra y en un 100% en la columna toracolumbar. Se comprobó el error de colocación (Grado III) en un pedículo de L3 en la concavidad de una escoliosis.No se observaron complicaciones relacionadas con los implantes.Conclusiones. El bajo porcentaje de tornillos mal colocados en este estudio se compara favorablemente con los resultados publicados en la literatura. Nuestros resultados indican que la cirugía guiada por imagen aplicada a la cirugía del raquis es una técnica segura para la fijación transpedicular (AU)
Introduction. Computer image guidance is one of the most significant technologic advancements in the spinesurgery, because preoperative or intraoperative images can be used for multiplanar, three-dimensional intraoperative navigation. Material and methods. We performed a prospective clinical study to assess the accuracy of pedicle screw insertion using an optoelectronic navigation system (SurgiGATE Spine 2.1 Medivision). The study population included 29 patients with diverse disorders of the thoracolumbar spine (degenerative 54%, spondylolisthesis 21%, fractures 14%, scoliosis 7% and spondylodiscitis 4%). One patient was excluded from the study because problems with the specific instruments or the computer system. Pre and post-operative axial computed tomography images were obtained for each patient and analyzed by two independent radiologists to place mentaccuracy. The correct location was defined accord to Heary scale in 5 grades. Results. 163 image-guided thoraco-lumbar pedicle screws were placed 29 in the thoracolumbar spine and 134 in the lumbosacral spine. We achieved a completely intraosseous placement (Grade I) in 99.4% of lumbosacral spine screws and 100% of thoracolumbar spinescrews. Only one misplaced screw (Grade III) in the pedicle of L III in the concavity of a scoliosis was reported. No implant related complications were noted. Conclusions. The low rate of misplaced screws in this prospective study compares favorably with previously published results. Our initial results indicate that Image-guided spinal surgery is a safe technique which improves surgical performance during posterior transpedicle stabilization (AU)
