Date Published: October 16, 2018
Publisher: Public Library of Science
Author(s): Chunjie Liu, Kunlun Yu, Jiangbo Bai, Dehu Tian, Guoli Liu, Chunfeng Zhao.
The adhesion of tendon and surrounding tissue is the most common complication after repairing an injured tendon. The injured flexor tendons in zone II are frequently accompanied by tendon sheath defects, which lead to poor recovery. A variety of biological and non-biological materials have been recently used for repair or as substitute for tendon sheaths to prevent tendon adhesion. However, non-biological materials, such as polyethylene films, have been used to prevent tendon adhesions by mechanical isolation. The possibility of tendon necrosis and permanent foreign body remains due to the lack of permeability and the obstruction of nutrient infiltration. The natural macromolecule amniotic membrane derived from organisms is a semi-permeable membrane with the following characteristics: smooth; without vascular, nerve, and lymphatic; and rich in matrix, cytokines, enzymes, and other active ingredients. The unique structure of this membrane makes it an ideal biomaterial. In the experiment in Henry chicken, the model of tendon sheath defect and the flexor digitorum tendon in zone II was established and randomly divided into control group, medical membrane group, and decellularized amniotic membrane group. Samples were obtained at the 2nd, 4th, 8th, and 12th week after operation. General, histological, and biomechanical tests were performed to investigate the preventive effect of repaired tendon sheath by decallularized amniotic membrane. Experimental results showed the following: the amniotic membrane group and the medical membrane group had mild inflammatory reaction and tissue edema, and nearly no adhesion was observed in the surrounding tissue; the fibroblast-like cells were distributed in layers under the light microscope; the amniotic membrane group was denser than the medical membrane group cells, and numerous fibroblasts were disorganized in the control group. Biomechanical measurements showed that the sliding distance of tendon, the total flexion angle of the toes, and the tendon maximum tensile breaking strength at the early postoperative were significantly better than in the control group. Through this experiment, the amniotic membrane, as a natural biological substitute material in the construction of tendon sheath, can effectively inhibit exogenous healing and promote endogenous healing to prevent tendon adhesion.
The adhesion of tendon and surrounding tissue is the most common complication after repairing an injured tendon. The injured flexor tendons in zone II are frequently accompanied by tendon sheath defects, which lead to poor recovery. With the theory of tendon endogenous healing and the comprehensive understanding of tendon sheath on tendon nutrition and protection, a variety of biological and non-biological materials have been recently used for repair or as substitute for tendon sheath to prevent tendon adhesion. However, due to different physical and chemical properties of these materials, their mechanisms of action and clinical effects are different. Biological materials include the tissue around the tendon, vein, and fascia transplantation[2–4]. Adopting these materials requires sacrificing other body tissues and cause new wounds; non-biological materials include polyethylene membranes, silicone membranes, cellophane, and absorbable gelatin sponges, which are obtained through mechanical isolation to achieve the purpose. With the in-depth tendon repair research, although such non-biological material membranes can isolate tissue from adhesion, these membranes have increased tendon necrosis and the possibility of permanent foreign body residue due to non-permeability, thereby impeding the penetration of nutrients.
In the field of hand surgery, 30% of cases suffer from tendon injury alone or associated with tendon injury. The anatomical structure of the flexor tendon in the hand zone II is complex and delicate, mostly presenting tendon sheath defects. Thus, tendon adhesion is prone to occur after tendon repair. Exogenous and endogenous methods are available for tendon healing. In exogenous healing of tendons, fibroblasts grow from the surrounding tissue to the ends of the tendons, thereby forming the adhesion of the tendons and surrounding tissues, hindering the normal sliding of tendons, and seriously affecting the motor function of the fingers. Such issues remain unsolved in the field of tendon injury repair[14, 15]. Inhibiting exogenous healing, promoting endogenous healing, reducing inflammation, controlling excessive fibroblast proliferation, and effectively recovering the tendon sliding function are keys to preventing tendon adhesion.