Repair of the dura mater with processed collagen devices.

BACKGROUND

We evaluated in a canine duraplasty model how specific differences in device physicomechanical properties, porosity, and crosslinking influenced the biological performance of three processed collagen dural substitutes.

METHODS

Three collagen dural substitutes were studied: Dura-Guard, DuraGen, and Durepair. The initial strength, stiffness, and suture retention force were measured using standard mechanical test methods. The relative pore sizes of each device were assessed with a scanning electron microscope. Differential scanning calorimetry was used to measure their respective collagen denaturation temperatures. The biologic response and performance of the materials were evaluated via an acute (1 month) and long-term (3 and 6 months) canine bilateral duraplasty study.

RESULTS

The mechanical properties of Dura-Guard and Durepair were similar to native dura. We could not quantify the mechanical properties of DuraGen because of its fragile nature. The denaturation temperature of DuraGen and Dura-Guard differed significantly from that reported for native collagens. The denaturation temperature of Durepair was comparable with the values reported for native collagens. All three materials were tolerated well by the animals. DuraGen did not maintain its structural integrity beyond 1 month. Dura-Guard and Durepair persisted for 6 months. Durepair was populated by fibroblasts and blood vessels, whereas Dura-Guard was not.

CONCLUSIONS

The three dural substitutes tested were found to be safe and effective in healing surgically created defects in the dura mater. Although each of these dura substitutes are composed of collagen, differences in the collagen source and processing influenced device physicomechanical properties, porosity, and the nativity of the collagen polymer. These measured differences influenced device intraoperative handling and installation as well as the post-operative biological response, where differences in device resorption, cell penetration, vascularization, and collagen remodeling were observed.