Presealing of the chorioamniotic membranes prior to fetoscopic surgery: preliminary study with unfertilized chicken
Helen K Carnaghan1, Michael R Harrison
1School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, United Kingdom. hcarnaghan@googlemail.com
Background:
Fetoscopic surgical techniques continue to develop. However, progress has been hindered by premature rupture of membranes (PROM), which complicates 5-30% of fetoscopic procedures. Several membrane closure techniques have been devised but none proven reliable.
Objective:
We propose a new approach that of presealing the chorioamniotic membrane prior to membrane disruption-a so called Amnioseal. A set of pilot experiments were designed using unfertilized chicken egg models to test our proposal.
Study Design:
Two novel unfertilized chicken egg models were developed. Model 1 simulated the chorioamniotic membrane and amniotic cavity. Model 2 simulated the uterine muscle/chorioamniotic membrane interface and amniotic cavity. Four sealants (100% petroleum jelly, FloSeal Hemostatic Matrix, CoSeal Hemostatic Matrix and BioGlue Surgical Adhesive) were tested against untreated controls. The sealants were applied directly to the egg membranes followed by biopsy needle puncture and needle membrane manipulation.
Results:
BioGlue adhered strongly to the membrane correlating with the smallest defect size, greatest resistance to rupture, lowest degree of leakage and formed a water tight seal around the needle during membrane manipulation. In comparison, the weak adherence of FloSeal correlated with a larger defect size and higher degree of leakage. 100% petroleum jelly was non-adhesive, provided no membrane support and resulted in membrane rupture.
Conclusion:
Adhesive sealants confer mechanical support to the membrane and form a water tight seal. Experiments show that Sealant properties greatly affect outcomes. As such the Amnioseal's success will be determined by the properties of the sealant used. Specifically designed sealants are being developed along side a delivery device and will be tested using an in vitro human chorioamniotic membrane model.
