ABSTRACT
Objetivo: Describir las alteraciones morfológicas de la cicatrización estromal y la reinervación por microscopia confocal en pacientes operados de LASIK posterior a queratotomía radial de 15 años de evolución. Métodos: Se realizó un estudio observacional, descriptivo y longitudinal prospectivo, en 25 pacientes (50 córneas) operados de queratotomía radial no complicados y reintervenidos con LASIK. Se estudiaron las características de la cicatrización estromal y la regeneración de fibras nerviosas corneales mediante microscopia confocal de la córnea con Confoscan S4. Se emplearon medidas de resumen de estadística descriptiva. Resultados: La cicatrización estromal se limitó al borde del colgajo. Hubo un aumento de la actividad queratocitaria en el lecho estromal en las primeras semanas del postoperatorio y disminución de la densidad queratocitaria por apoptosis observada hasta el año de evolución. En el preoperatorio de LASIK el número de plexos nerviosos se encontraban normales en más del 80 % de las córneas. En los primeros tres meses posoperatorios existió ausencia de reinervacion, su recuperación comenzó entre el sexto y octavo mes, con evidente alteración de la morfología y cantidad de plexos nerviosos por campo de microscopia confocal al año. Conclusiones: Las características de la cicatrización estromal estudiadas evolucionaron de manera similar a lo descrito en pacientes que no presentaban dicha queratotomía radial como antecedente. La regeneración nerviosa comenzó a partir de los seis meses con la aparición de los nodos nerviosos y un aumento progresivo de la sensibilidad corneal.
Objective: To describe the morphological alterations in the stromal scaring and re-inervation by using confocal microscopy in patients operated on with LASIK after radial postkeratotomy of 15 years old evolution. Methods: A prospective, longitudinal, observational and descriptive study was conducted in 25 patients (50 corneas) operated on by radial keratotomy, with no further complications and re-operated on with Laser in Situ keratomileusis (SHWIND Esiris). The characteristics of the corneal structures and the regeneration of corneal nervous fibers were studied by means of confocal microscopy with Confoscan S4. Summary measures were used. Results: The stromal scaring was limited on the edge of the flap; there was an increase of the keratocyte activity in the stromal channel during the first weeks of the postoperative period and a decrease of the keratocyte density caused by apoptosis observed up to one year of evolution. Before Lasik, the number of nervous plexuses was normal in more than 80% of the corneas with incisional corneal surgery. In the first 3 postoperative months there was no nervous regeneration; but this process began between 6th and 8th months, with evident alteration of the morphology and quantity of nervous plexuses per field of confocal microscopy a year after surgery. Conclusion: The evolution of the microscopic characteristics of the cornea, which were studied with microscopy confocal in patients operated on by Lasik after radial keratotomy, was similar to that described in patients who had not undergone this type of surgery. The nervous regeneration began after 6 months when nervous nodes and progressive increase of corneal sensitivity occurred.
ABSTRACT
Avaliou-se macro e microscopicamente o tecido cicatricial pós-operatório de eqüinos submetidos a duas técnicas de neurectomia digital: guilhotina (TG) e stripping (TS). Decorridos 14 meses das cirurgias, foram colhidas 32 amostras de tecido cicatricial em quatro éguas, que tiveram os membros submetidos a ambas as técnicas. À macroscopia, verificaram-se as dimensões da cicatriz do coto proximal e a distância entre os cotos proximal e distal. À microscopia, foi quantificada a proporção de tecido nervoso regenerado por meio de histomorfometria. Não houve diferença nas dimensões do tecido cicatricial, contudo a distância entre cotos foi 5,6 vezes maior na TS (P<0,001). Histologicamente, observou-se a presença de tecido conjuntivo frouxo e denso, macrófagos e fibras nervosas delgadas em ambas as técnicas cirúrgicas. Estruturas nodulares, compostas por fascículos nervosos, foram visualizadas em 56,2 por cento (9/16) das amostras colhidas em nervos submetidos à TS. As porcentagens médias de tecido nervoso no tecido cicatricial foram de 0,31 por cento na TG e 2,6 por cento na TS (P<0,001). Concluiu-se que o retorno à sensibilidade nervosa deve demorar mais a ocorrer após a TS, devido à maior distância entre cotos. A maior proporção de tecido nervoso sugere que essa técnica favorece a regeneração nervosa.
The post-operative healed tissues in horses submitted to two digital neurectomy techniques, the guilhotine (GT) and the stripping (ST), were evaluated by macroscopy and microscopy. Fourteen months after surgery, 32 samples of scar tissue were collected from four mares that had the members experimentally submitted to both surgical techniques. By macroscopy, the dimensions of the scar tissue of the proximal stump and the distance between nerve stumps were taken. By microscopy, the proportion of nervous tissues in the scar tissue was quantified by histomorphometry. There were no differences between the scar tissue dimensions, but the distance between stumps was 5.6-fold greater in ST subjects. Histologically, connective tissue, macrophages, and thin nervous fibers were observed in scar tissue present in animals of both groups. Nodular structures composed by nervous fascicules were visualized in 56.2 percent (9/16) of the samples collected from the ST group. The mean percentage of the nervous tissue in scar tissue was 0.31 percent in GT samples and 2.6 percent in ST samples (P<0.001). After ST, a longer time to the return of the sensibility may occur due to the greater distance between stumps. However, greater proportion of nervous tissue in the scar tissue suggests that the use of this technique favors nervous regeneration.