REDUCTION OF PERIDURAL FIBROSIS AFTER LUMBAR LAMINOTOMY AND DISKECTOMY IN DOGS BY A RESORBABLE GEL (ADCON-L)

Study Design. A canine lumbar laminotomy and discectomy model was used to evaluate the effects of a resorbable gel, ADCON-L (Gliatech Inc., Cleveland, OH), in reducing peridural scar formation and to assess the healing progress of immediately adjacent normal structures. Objective s. To compare peridural scar formation and anulus fibrosis healing wit h and without the use of ADCON-L in an animal model that closely repli cates the common human surgical procedure. Summary of Background Data. ADCON-L has been shown to reduce the development of peridural scars i n rat, rabbit, and canine laminectomy models in previous investigation s; discectomies were not performed in these previous studies, however, and thus anular healing could not be assessed. Methods. Seven adult m ongrel dogs underwent a three-level unilateral lumbar hemilaminotomy a nd anular fenestration. In each dog, the ADCON-L was applied to two ra ndomly assigned sites around the discectomy, the nerve roots, and the hemilaminotomy. The third site underwent surgery, but was left untreat ed (sham surgery only). The canines were killed 8 weeks after surgery, and a gross anatomic assessment of scar formation was done using micr odissection by an observer blinded to treatment. A numerical rating sy stem was developed to assess the relative amount and tenacity of the a nterior scarring (discectomy site) and posterior scarring (hemilaminot omy site). The healing of the anular defect was assessed histologicall y. Results. ADCON-L significantly reduced peridural fibrosis in this l umbar discectomy model compared with the sham treated sites(P < 0.05). Further, the superficial layers, the posterior longitudinal ligament, and the anulus fibrosus healed well in the ADCON-L treated sites. Con clusions. ADCON-L reduced local peridural fibrosis after lumbar lamino tomy and discectomy without impacting the healing of the surrounding t issues.