Immediate effects of diamond burr debridement in patients with spontaneous chronic corneal epithelial defects, light and electron microscopic evaluation
Fonte: Charlotte Dawson, Carolina Naranjo, Belen Sanchez-Maldonado
Case no.7 demonstrating the light microscopic ﬁndings of the (A) non-burred and (B) burred samples of the same sample in HE,MT and PAS. The burred samples show a decreased HAZ (black arrow).
Purpose To evaluate immediate effects of diamond burr debridement (DBD) on the cornea of canine patients diagnosed with spontaneous chronic corneal epithelial defects (SCCEDs).Animals studied Eight client owned dogs with SCCEDs.Methods Nine eyes from eight dogs with SCCEDs underwent superﬁcial keratectomy(SK). The ulcerated area was divided into quadrants with a 300-micron restricted depth knife. Two of four quadrants underwent DBD for 40–60 s. A SK followed immediately. One burred section and one nonburred section were ﬁxed with formaldehyde 10% and underwent light microscopy (LM). The remaining quadrants from ﬁveeyes were ﬁxed with glutaraldehyde 2.5% and underwent transmission electron microscopy (TEM). Masked pathologists evaluated the samples. A student’s paired t-test was used to analyze the data.Results With LM all nonburred samples had a superﬁcial stromal hyaline acellular zone (HAZ), seven of the burred samples had an intermittent HAZ and in two burred samples this zone was absent. The HAZ thickness of burred samples(1.062 0.664 lm) was signiﬁcantly thinner than that of the nonburred samples(4.309 1.348 lm) (P < 0.0001). Transmission electron microscopy showed an absence of basement membrane and the presence of an amorphous, ﬁne ﬁbrillar mate-rial in the superﬁcial stroma in nonburred samples. This material was intermittent or absent in burred samples.Conclusion DBD signiﬁcantly reduces the superﬁc ial stromal HAZ in SCCED s. A reduction of its thickness may be responsible for the healing rates reported with DBD.