Connective tissue scarring in experimental spinal cord lesions: significance of dural continuity and role of epidural tissues.

Neoformation of connective tissue occurring at the level of spinal cord injury is considered a factor in the failure of regeneration in the mammalian spinal cord. The purpose of the present research was to experimentally investigate the origin and characteristics of connective proliferation following spinal cord lesion produced by compression in the rat. The role of the dural sheath and that of the tissues surrounding the spinal cord were studied. In one group of animals (1), the dura mater was left intact; in a second group (2) a transverse incision of the dura was performed at the level of the spinal cord compressive lesion. In group (1) a few collagenous fibres were seen within the lesion but no connective septum was observed. In group (2) a transversely orientated septum of fibrous scar tissue was constantly found within the lesioned cord. Our experimental study shows that: 1. dural continuity prevents the formation of connective tissue scarring and limits fibrous reactions in the epidural space; 2. opening of the dural sheath is followed by a vigorous fibroblastic reaction in the epidural tissue which extends into the spinal cord to form a connective septum.