Pre-clinical subdural tissue reaction and absorption study of absorbable hemostatic devices

SURGIFOAM (TM) (Absorbable Gelatin Sponge, USP), a new absorbable hemostati c sponge, GELFOAM((R)) (Absorbable Gelatin Sponge, USP) or Avitene((R)) (mi crofibrillar collagen hemostat) were evaluated in a three-month tissue reac tion and absorption study in rabbits. Bilateral craniotomy was followed by subdural implantation of each hemostatic device. A sham control group was t reated in a similar way except that no material was implanted. Implantation of these hemostatic devices for 15, 43, or 92 days did not result in any d eaths or clinical neurobehavioral abnormalities, changes in cerebrospinal f luid, or significant macroscopic observations at necropsy. The tissue react ion to SURGIFOAM (TM) sponge was characterized by transient granulomatous i nflammation that was slightly less intense than that observed for GELFOAM(( R)) sponge which correlated to slightly longer absorption. In contrast, the tissue reaction to Avitene((R)) hemostat was characterized by moderate to marked granulomatous inflammation with an acute inflammatory component indi cating a greater degree of tissue irritancy. Sequelae of this reaction were still observed at 92 days post-implantation. The tissue reaction in humans to SURGIFOAM (TM) sponge used as a hemostatic agent for neurologic surgica l procedures is expected to be comparable to that observed with CELFOAM((R) ) sponge, resulting in no significant adverse reactions for patients. This animal model was useful to assess the tissue reaction and absorption of bio materials implanted in contact with the central nervous system, and it was able to differentiate between materials of biologic origin.