ABSTRACT
PURPOSE: To determine the stability of the laser in situ keratomileusis (LASIK) flap in a rabbit model when subjected to vertical acceleration at nine times the force of gravity (+9 Gz) in an aircraft cockpit ejection simulator. METHODS: Thirty-six eyes from 25 New Zealand white rabbits underwent LASIK flap creation without laser photoablation. One month after surgery, the rabbits were sedated and harnessed in a cockpit ejection seat simulator used to train United States Air Force pilots. They then underwent a controlled rapid-sequence ejection at +9 Gz. Subsequently, the rabbits were euthanized and the corneas harvested for microscopic examination. Refractive measurements and corneal examination were made before LASIK flap creation and prior to and after the +9 Gz ejections. Determination of LASIK flap dislocation was based on clinical observation of flap slippage or a significant shift in pre-ejection to postejection cylinder axis. RESULTS: The average preoperative refraction of the rabbit eye was +1.83 D + 3.25 D x 086 degrees. The average change from pre-ejection to postejection was 0.04 D sphere, 0.02 D cylinder, 6.8 axis degrees, and 0.04 D spherical equivalent. The pre-ejection to postejection measurements were not statistically significantly different by a paired test. Laser in situ keratomileusis flap dislocation or ejection-induced corneal folds or striae were not clinically observed. Histologic examination revealed well-healed LASIK flaps but no reactive keratocytes at the central stromal-stromal interface. CONCLUSIONS: Healed LASIK flaps as created in this rabbit model without laser ablation are stable when subjected to a rapid vertical ejection at nine times the force of gravity.
Subject(s)
Aerospace Medicine , Cornea/surgery , Hypergravity/adverse effects , Keratomileusis, Laser In Situ , Postoperative Complications , Surgical Flaps , Wound Healing/physiology , Aircraft , Animals , Military Medicine , Postoperative Complications/physiopathology , Rabbits , SafetyABSTRACT
Se presentan 4 pacientes con perforación esofágica causada por traumatismos externos y cuerpos extraños cuyas evoluciones fueron tórpidas. Se discuten aspectos clínico-terapéuticos y técnico-quirúrgicos tanto de las perforaciones cervicales como torácicas, poniendo énfasis en la importancia de la precocidad del diagnóstico y la agresividad terapéutica (AU)
Subject(s)
Child , Adolescent , Middle Aged , Humans , Male , Female , Esophageal Perforation/surgery , Foreign Bodies , Wounds and InjuriesABSTRACT
Se presentan 4 pacientes con perforación esofágica causada por traumatismos externos y cuerpos extraños cuyas evoluciones fueron tórpidas. Se discuten aspectos clínico-terapéuticos y técnico-quirúrgicos tanto de las perforaciones cervicales como torácicas, poniendo énfasis en la importancia de la precocidad del diagnóstico y la agresividad terapéutica
