Conjunctival expansion using a subtenon's silicone implant in New Zealand white rabbits

Abstract

Purpose: In the field of ophthalmology, the conjunctival autograft is a useful therapeutic material in many cases, but the small size of the autograft is a disadvantage. Therefore, we evaluated the feasibility of taking an expanded sample of conjunctival tissue using a subtenon's silicone implant.

Materials and methods: We included a total of nine rabbits; eight rabbits were operative cases, and one was a control. A portion of conjunctival tissue from the control rabbit, which did not undergo surgery, was dissected and examined to determine whether it was histologically different from the experimental group. The surgical procedure was performed on eight rabbits via a subtenon's insertion of a silicone sponge in the left superior-temporal portion; after surgery, we dropped antibiotics into the eyes. We sacrificed a pair of rabbits every three days (on days 3, 6, 9, and 12) after surgery, removed the expanded conjunctival tissues with the silicone sponge implants, and measured their sizes.

Results: The mean size of the expanded conjunctival tissues was 194.4 mm2. On the third day, we were able to harvest a 223.56 mm2 section of conjunctival tissue, which was the most expanded sample of tissue in the study. On the twelfth day, we removed a 160.38 mm2 section of conjunctival tissue, which was the least expanded sample of tissue. Statistically, there were no significant differences in the mean dimensions of the expanded conjunctival tissues for each time period. Microscopic examinations showed no histological differences between the expanded conjunctival tissues and the normal conjunctival tissues.

Conclusion: The results reveal that this procedure is a useful method to expand the conjunctiva for grafting and transplantation.

Fig. 1

Insertion of a silicone sponge, and suture of the conjunctiva and Tenon's capsule.

Fig. 2

The dimensions of the conjunctival tissue obtained from each rabbit.

Fig. 3

One case developed local scarring in the conjunctiva.

Fig. 4

Histological findings of the conjunctival scarring (Hematoxylin-Eosin (HE) staining, × 200).

Fig. 5

Histological findings of the conjunctiva after the procedure. (Hematoxylin-Eosin (HE) staining, × 200). (A: Three days after the procedure B: Six days after the procedure C: Nine days after the procedure D: Twelve days after the procedure)

Fig. 6

Histological findings of the normal conjunctiva (Hematoxylin-Eosin (HE) staining, × 200).