RESUMEN
PURPOSE: To evaluate whether performing same-day pars plana vitrectomy versus delayed pars plana vitrectomy affects visual outcomes and ocular morbidity of patients with retained lens fragments after a complicated cataract surgery. METHODS: Retrospective, comparative case series of 172 eyes of 171 patients with retained lens fragments undergoing 3-port pars plana vitrectomy using 20-, 23-, or 25-gauge instrumentation between 2005 and 2008. Outcome measures included best-corrected visual acuity at 6 months, final best-corrected visual acuity, and postoperative complications such as cystoid macular edema, intraocular pressure elevation, retinal detachment, vitreous hemorrhage, choroidal hemorrhage, and endophthalmitis. RESULTS: The median age was 75 ± 0.8 years. The mean time to vitrectomy for the delayed group was 15 ± 2 days. The preoperative logarithm of the minimum angle of resolution best-corrected visual acuity for immediate vitrectomy was 0.73 ± 0.09 versus 0.72 ± 0.06 for delayed vitrectomy. Six-month logarithm of the minimum angle of resolution acuity was 0.44 ± 0.09 for same-day vitrectomy compared with 0.44 ± 0.05 for delayed vitrectomy (P = 0.97, 2-tailed t-test). Of 59 eyes undergoing immediate vitrectomy, 17 (29%) experienced postoperative complications, while 38 of 113 eyes (34%), experienced complications if undergoing delayed vitrectomy (Fisher exact test, P = 0.61). Overall, the most common complication was cystoid macular edema occurring in 25 of 172 eyes (15%). CONCLUSION: The outcomes of same-day pars plana vitrectomy appear to be similar to non-same-day pars plana vitrectomy. The risks and benefits related to the timing of vitrectomy after a complicated cataract surgery should be carefully discussed with each patient. Further investigation is warranted to establish an optimal time for surgical planning.
Asunto(s)
Subluxación del Cristalino/cirugía , Facoemulsificación/efectos adversos , Vitrectomía/métodos , Anciano , Femenino , Humanos , Subluxación del Cristalino/etiología , Subluxación del Cristalino/fisiopatología , Masculino , Microcirugia/métodos , Complicaciones Posoperatorias , Estudios Retrospectivos , Medición de Riesgo , Factores de Tiempo , Resultado del Tratamiento , Agudeza Visual/fisiologíaRESUMEN
The aim of this study was to carefully assess the level of modulation in electrical excitability of single neurons with the application of high frequency ultrasound. High frequency tone bursts of ultrasound have been shown to dramatically increase the spike frequency of primary hippocampal neurons in culture. In addition, these ultrasonic bursts also induce silent or still developing neurons to fire. Results indicate that the increase in excitability is largely mediated by mechanical effects and not thermal effects of ultrasound. Future studies on culture models exposed to varying ultrasound protocols may provide insight into the feasibility of using ultrasound as a means for neurostimulation studies conducted on brain slice and in vivo models.
Asunto(s)
Neuronas/patología , Ultrasonido , Algoritmos , Animales , Encéfalo/patología , Sistema Nervioso Central/patología , Medios de Cultivo/metabolismo , Impedancia Eléctrica , Electroquímica/métodos , Diseño de Equipo , Hipocampo/patología , Modelos Biológicos , Neuronas/metabolismo , Neuronas/fisiología , Ratas , Ratas Sprague-Dawley , Factores de TiempoRESUMEN
High frequency tone bursts of ultrasound are capable of increasing the sensitivity of rat motor cortex to electrical stimulation. In this study, 11.75 MHz ultrasound pre-stimuli were delivered to the forelimb motor region of the rat cortex followed by an electrical pulse train to assess changes in cortical activation. The temporal peak intensity of the ultrasound delivered to the brain ranged from 100 to 150 W/cm(2). Tone bursts of 10 to 50 ms in duration were delivered once per second over periods of 30 to 240 seconds. The intracortical microstimulation (ICMS) current needed for forepaw motor response decreased by as much as 40% when applying 50 ms ultrasound pulses. Brain excitability changes were seen with a thermal index (TI) as low as 2.0. Ultrasound application alone was not able to induce motor responses.