New dried human amniotic membrane is useful as a substitute for dural repair after skull base surgery

Objectives: Cerebrospinal fluid (CSF) leakage is an undesirable complication of skull base surgery.We used dried human amniotic membrane (AM) as a patch graft for dural repair to determine its efficacy in preventing CSF leakage. Design: Frontoparietal craniotomy and removal of dura were performed in 20 Wistar rats. A dried AM was placed to cover the dural defect without suturing in 16 animals. In four animals, an expanded polytetrafluoroethylene was implanted. At 2 weeks and 1, 3, and 6 months, histological examination was performed. Dried AM was also used as a substitute in 10 patients who underwent skull base surgery, after approval by the Ethics Committee of the University of Toyama. Results: At 2 weeks after implantation, thick connective tissue completely enclosed the dried AM. At 1 month after implantation, the connective tissue became thin and the implanted AM shortened. At 3 and 6 months after implantation, histological examination revealed disappearance of the dried AM and formation of membranous tissue. In the clinical study, neither CSF leakage nor clinical adverse reactions directly related to the dried AM were observed. Conclusion: Dried human AM appears to be an ideal substitute for dura, since it is replaced by natural tissue.