Freeze-dried amniotic membrane for repair of dural defects

Nianping ZHANG; Fang LIU; Xuewen TIAN; Yong ZHANG

ABSTRACT

BACKGROUND:

Amnion has been widely used in ophthalmology. Numerous studies have suggested that amnion transplantation did not induce acute immunologic rejection. These indicated that amnion transplantation can be used as a safe material for repair of dural defects.

OBJECTIVE:

To study the probability of freeze-dried amniotic membrane (FDAM) as a dural substitue.

METHODS:

Each of the guinea pigs underwent bilateral parietal craniectomy behind the coronal suture and beside the midline to expose the dura. On the right side, a piece of dura mater was removed. The dural defect was covered with a piece of FDAM. The exposed dura on the left was cut and sutured itself as control. The animals in each group were sacrificed at 15, 30, 60 and 90 days after operation, respectively. The implants were harvested and stained with hematoxylin-eosin, and histologically analyzed. RESULTS AND

CONCLUSION:

After operation, the behavior of all guinea pigs remained completely normal. The wound healing was achieved in all cases. No wound infection, subcutaneous effusion or cerebrospinal fluid (CSF) leakage occurred. The graft was degraded gradually and covered with a sheet of connective tissue. Dural defects repaired with FDAM showed no adhesions to the brain surface. 15 days after operation, plenty of scattered fibroblasts appeared in the dural substitute. 30 days alter dural graft implantation, parts of the implant disappeared; meanwhile the hyperplasia of fibrous connective tissue took place in the center part of the dural substitute, without the infiltration of inflammatory cells. 60 days after implantation, a majority of the dural graft was degraded, substituted by fibrous connective tissue which was of hyperplasia and low-grade degeneration, surrounded by a small quantity of giant cells. 90 days after operation, colloidal degeneration happened in the dural substitute, surrounded by ossification tissue and the degenerated fibrous connective tissue. The inflammatory cells were not discovered. The animal experiment proves FDAM to be a safe and applicable dural substitute.