Experimental Study On The Repair Of Canalicular Lacerations In Rabbits

0bjective: In this experiment, an animal model of canalicular lacerations by intersecting thecanaliculus was established in rabbits and canalicular anastomosis combined withintubation was executed.The healing process of rabbits in anastomotic region at differenttime after surgery were observed, including histopathologic change in anastomotic regionand the best time of silicone extubation.Methods: Approximately3mm medial to the punctum a full-thickness eyelid incisionthrough the canaliculus was executed to establish the animal model of canalicularlacerations.16rabbits without eye disease were randomly divided into A, B and C threegroup. Group A (4eyelids)was the normal control group.In group B (4eyelids),thecanaliculi were repaired by canalicular anastomosis without silicone intubation. In group C(24eyelids), the canaliculi were repaired by canalicular anastomosis combined withsilicone intubation. This group was divided into three subgroups according to different timewhen the silicone tube was removed. That is1month subgroup(8eyelids), two monthssubgroup (8eyelids) and three months subgroup (8eyelids).4months after surgery, thepatency of the canlicular systerm was assessed by irrigation test, endoscopy examination,and pathological examination using routine HE stain in each group. In group C, irrigationtest, endoscopy examination, and pathological examination were also made at every silicone extubated time.Results: In group A, All of the canaliculi were found to be patent by irrigation test. Themucosa of the canaliculi were normal by the endoscopy examination. The structure of thecanaliculi were also normal by the pathological examination. In group B, none of thecanaliculi were found to be patent by irrigation test. With endoscopy examination, the wallof canalicular was rough, thickened, with a grey white color, and a lot of inelastic off-whitemembrane substance floating in the lumen. Through pathological examination, thesignificant canalicular epithelium hyperplasia, arranged in a multilayer, little inflammatoryreaction, and normal subepithelial structure were observed. In subgroup of the siliconeextubated at1month in group C, three of the four canaliculi were patent by irrigation test;with endoscopy examination, the mucous membrane appears pale pink, the wall of thecanaliculi were a little rough, with a little membrane substance floating in the lumen.Through pathological examination, the epithelial of the canaliculi returned to be normal, thelumen was also normal, but there were little epithelial defects, and the loose connectivetissue of the subepithelial had shown a proliferative state. In subgroup of the siliconeextubated at2month in group C, one of the four canaliculi were patent by irrigation test.With endoscopy examination, pink mucous with small hemorrhagic spot on superficial,narrow lumen, pale scars and a lot of membrane material were found. Epitheliumproliferation, canaliculi stenosis, and the loose connective tissue of the subepithelialproliferation were abserved. In subgroup of the silicone extubated at3month in group C,three of the four canaliculi were patent by irrigation test, and two canaliculi were stenosisamong the pantened canaliculi, With endoscopy examination, pale pink mucous, canalicularlumen hypertrophy, stenosis., and a lot membrane material floating in the lumen were found.Through pathological examination, moderate epithelium hyperplasia, normal lumen andnormal subepithelial structure were observed. In group C, the canaliculi of each subgroupat4months were similar to that at2month by endoscopy examination and pathologicalexamination. Conclusion: The silicone intubation of the canaliculs is an effective method to repair thelacerated canaliculus. It is advisable that silicone extubation should be done one monthafter the surgery, since that the scar was more obvious at2month and3month after isilicone ntubation.