[Clinical and histopathological studies of the suture made of DCFF-treated natural collagen fiber].
Natural and synthetic fiber sutures used clinically, especially twist or braid type ones, will remain to the region after healing by the first intention and often cause inflammation by capillarity. It is necessary to remove those sutures from healing wounds. To obviate this necessity, we separated collagen fibers from a tendon of a rat's tail, gave them DCFF treatment for immunological tolerance, and made collagen sutures on an experimental basis. The discussion on the clinical, histopathological and physical properties of the collagen sutures proved their superiority over any other type of suture currently used. (DCFF treatment: decalcifying, defatting and freeze-drying a material previously fixed in formalin.) 1. Results of Clinical Application: Collagen sutures immersed in 70% ethanol, contacting saliva, were easily handled and fell off spontaneously in about 7 days after operation. Thus removing sutures aren't necessary. 2. Histopathological Characteristics: (1) Biopsy observations show that the collagen sutures disclosed outside of the tissues were gradually decomposed by the activity of microbes in the oral cavity, falling off spontaneously in 7-10 days by the time of healing by the first intention, whereas those inside the tissues were more slowly absorbed. (2) The major portion of the collagen sutures, implanted in the dermis of a rat's back, was decomposed and absorbed in one week or 3 months at latest, with some portion encapsulated. All nylon sutures remained without being decomposed; most silk sutures, neither easily decomposed nor encapsulated, remained and occasionally caused distinct inflammatory rejection. 3. Physical Characteristics (load and elongation test): A tensility comparison between silk sutures (4-0 U.S.P. standard) with the collagen sutures of the same thickness showed the collagen sutures were stronger than the silk ones when they are wet.