EFFICACY AND BIOCOMPATIBILITY OF A PHOTOPOLYMERIZED, SYNTHETIC, ABSORBABLE HYDROGEL AS A DURAL SEALANT IN A CANINE CRANIOTOMY MODEL

Object. A canine craniotomy model was used to evaluate the dural seali ng efficacy and biocompatibility of a novel, synthetic, bioresorbable hydrogel. Methods. Bilateral craniotomies were performed in 24 dogs as signed to six survival periods. In each animal a parasagittal durotomy was created and then repaired. At the treatment sites the hydrogel se alant was applied over the dural repair and photopolymerized. The repa ir was tested for leaks to 20 cm H2O by using a Valsalva maneuver. At the control sites the incisions were sutured and tested for leaks only . After uneventful survival periods, the leak test was repeated in thr ee of the four animals in each group. Bone-dura adhesion was evaluated , after which the dura and underlying brain were removed, fixed, and e xamined histologically. En bloc histological investigation was perform ed on a specimen obtained from the fourth animal in each group. Over a 56-day period, 18 treated sites were tested for leaks. A leak was det ected at a site remote from that of the repair in one animal; this was excluded from analysis. Thus 17 of 17 treated sites remained free of leaks. On the control side of one animal. there was a leak from a new dural tear at the cranial end of the durotomy, which occurred when the bone flap was removed. This site was also excluded from analysis. Ele ven of 17 leak-tested control sites remained free of leaks over the st udy period. Bone-dura adhesions occurred in 15 of 19 control sites and had a mean adhesion score of 1.37 (range 0-4), whereas adhesions occu rred in 10 of 19 treated sites with a mean adhesion score of 0.84 (ran ge 0-3). No cortical reaction was noted. Conclusions. This novel hydro gel sealant is efficacious in sealing dural repair sites measuring up to 2 mm. Healing of the underlying dura is not compromised and exposed cortical tissue is not altered histologically.