Abstract: A pin for attaching a surgical membrane barrier to tissue structure of a patient comprises a pin body 1 formed from a sequence of four truncated cones which define a serrated profile which enables the pin to engage the membrane barrier and to be pushed-fitted into the tissue structure. The head portion 2 of the pin serves to engage the membrane barrier and retain it in position on the underlying tissue structure.The pin is made from a resorbable polymer, such as PDS Polydioxanone and is of substantially solid construction throughout.In an alternative embodiment, a circularly cylindrical extension is provided between the largest truncated cone and the pin head. The arrangement serves to maintain a spacing between the membrane barrier and the underlying tissue.