Histology after dural grafting with small intestinal submucosa

The search for the ideal dural substitute continues, inasmuch as available materials have significant limitations. Xenogeneic porcine small intestinal submucosa (SIS) has been successfully used as a soft tissue graft in several body organ systems, and it was logical to evaluate its use as a dural replacement.

Twenty rats underwent bihemispheric craniectomy with dural resection. SIS onlay grafting on one side was performed. Histologic assessment was obtained at 7 and 28 days after dural grafting and included descriptive evaluation and quantitative scoring of graft-site thickness, vascularity, and cellular density. The total scores for the respective groups were compared using the Student's t test, significance being accepted for a p value < 0.05.

Histologic evaluation showed graft infiltration by spindle-shaped mononuclear cells, deposition of connective tissue, and neovascularity. This pattern is consistent with the previously described incorporation and remodeling of the SIS graft at other sites. A significant difference between the histologic scores of the SIS graft site and control site was found at 7 days (3.4 +/- 0.8 versus 0.1 +/- 0.1) and at 28 days (4.6 +/- 1.1 versus 2.2 +/- 0.5). No evidence of adverse effect on the underlying cortex was observed.

The results of this preliminary study utilizing porcine SIS as a dural substitute are promising and therefore justify further chronic studies.