Porcine small intestinal submucosa as a dural substitute

BACKGROUND The continuing search for the ideal dural substitute is currently directed toward collagen preparations. Xenogeneic porcine small intestinal submucosa (SIS), a naturally occurring extracellular matrix rich in collagen, has been successfully used as a soft tissue graft in several body organ systems, including preliminary studies as a dural substitute in the rat. METHODS Eight dogs underwent temporoparietal craniotomy and dural resection with replacement by SIS. Five dogs had contralateral procedures without SIS grafting. Three dogs had contralateral SIS grafts placed 2 months after the initial procedure. Histologic assessment was obtained at 7, 30, 60, 90, and 120 days. Cerebrospinal fluid (CSF) cytological examination and routine serum chemistry preceded sacrifice. RESULTS Histologic evaluation showed initial graft infiltration by mononuclear round cells, spindle-shaped cells within an eosinophilic staining extracellular matrix, and neovascularity. Complete resorption of the graft was evident by 60 days. This pattern is consistent with the previously described incorporation and remodeling of the SIS graft at other sites. CSF cytology and routine serum chemistry at the time of sacrifice were normal. Response to repeat grafting was identical to that of initial exposure. There was no clinical or histologic evidence of sensitization or graft rejection. No evidence of adverse effect on the underlying cerebral cortex was observed. CONCLUSIONS Porcine small intestinal submucosa demonstrates a favorable biologic response as a dural substitute in the canine model. It is a promising biomaterial for dural replacement.