Abstract
Purpose:
Postoperative scarring and adhesions after strabismus surgery are common and may affect surgical outcomes. Amniotic membrane grafts (AMG) have previously been shown to serve as a successful platform for healing and to reduce scarring in cases of ocular surface disease. Mixed results have been observed when using AMG in conjunction with strabismus surgery. This study was designed to evaluate the wound strength and histopathologic changes on postoperative wound strength of amniotic membrane grafting in conjunction with strabismus surgery using an in-vivo animal model.
Methods:
Inferior rectus hang-back recession with processed dehydrated amniotic membrane allograft (Ambiodry2, IOP Inc., Costa Mesa, CA) placed both between the sclera and the extraocular muscle and between the extraocular muscle and the repositioned conjunctiva was performed on 10 eyes of 10 New Zealand white rabbits. Inferior rectus recession without amniotic membrane grafting was performed on the alternate eye as a control. At postoperative month 1, tensile strength of the muscle and overlying conjunctiva was measured. Eyes were then enucleated and histopathologic analysis performed to evaluate scarring and inflammatory response.
Results:
Mean tensile strength of the AMG treated muscle and conjunctiva was 441.4 +/- 274.4g and 640.3 +/-266.4g respectively. The tensile strength of the control muscle and conjunctiva was 365.8 +/-199.8g and 595.2 +/- 315.3g respectively. No statistically significant difference was detected based on ANOVA testing. Histopathology demonstrated an increase in inflammatory infiltrate at the muscle stump in AMG treated muscle.
Conclusions:
There was no significant change in tensile strength of the muscle insertion at post op month one in muscles treated with amniotic membrane graft at the time of strabismus surgery. Significant intra-animal variation in tensile strength was observed, making a change difficult to detect. Further study is required to determine the long term effect of amniotic membrane grafting on post-operative scarring in strabismus surgery.