Tissue Substitute: Expanded Polytetrafluoroethylene(EPTFE)

- Sep 14, 2020-

With the development of science and technology and the progress of chemical synthesis industry, biological tissue substitutes suitable for human body have become a reality. The progress of organizational substitutes will promote the development. In the 1970s, the commonly used biological tissue substitutes were liquid silica gel, ivory, dental materials, solid silica gel, artificial bone materials and expanded polytetrafluoroethylene.

Liquid silica gel: widely used in China in the late 1970s and early 1980s, liquid silica gel injection augmentation nose, clinical observation has proved that after surgery can cause persistent erythema, swelling, nasal bridge skin necrosis and pulp tooth swelling, and even damage the face. Moreover, the liquid silica gel can diffuse, infiltrate and permeate around, and it is difficult to treat without clear boundary. In the United States, it has been strictly prohibited. Many domestic scholars hold that it is forbidden to use it with caution.

Ivory: it has good biocompatibility, and generally does not have rejection reaction. However, due to its hardness, difficulty in sculpture and animal protection, it is gradually abandoned for augmentation nose.

Dental materials: polymethacrylic acid and methyl ester (PMMA) are used as dental materials for augmentation nose, which is one of the earlier solid biological tissue substitutes for augmentation nose. It has good biocompatibility. It needs to be mixed when used in augmentation rhinoplasty, and it is easy to be polluted. In addition, incomplete preoperative contamination can easily lead to complications such as infection, pain and rejection. The prosthesis preparation is more complicated and the operation is relatively difficult, so it has been rarely used.

Solid silica gel: is currently commonly used augmentation nose material, for the polymer silicide. It has been used as early as 1972. After more than 20 years of observation, although the incidence of complications can reach 5% - 20%, it is still one of the preferred augmentation rhinoplasty materials because of its good biocompatibility and low price. Its main disadvantage is that it can not establish blood circulation with the body and form tissue connection. It is only wrapped by fibrous tissue, so it can penetrate through the skin in the weak tissue. Because of the contracture of the fibrous capsule, the body surface projection of silicone prosthesis can be caused, and the appearance effect is affected.

Artificial bone materials: mainly refers to hydroxyapatite. It is the main inorganic component of human bone tissue, so it has good biocompatibility, non-toxic, teratogenic, sensitizing and carcinogenic side effects. It has been widely used in stomatology and orthopedics. Since the mid-1980s, it has been used in augmentation rhinoplasty. It is easy to operate and shape, especially for those with low bridge of nose. Because it has no supporting effect, it has poor effect on patients with low nasal tip.

Expanded polytetrafluoroethylene (ePTFE): from a medical point of view, it is an ideal biological tissue substitute. Because of its good biocompatibility and unique microporous structure, it is non-toxic, carcinogenic and non sensitizing. Moreover, human tissue cells and blood vessels can grow into its micropores to form tissue connection, just like autologous tissue. The effect of augmentation rhinoplasty is satisfactory. EPTFE augmentation rhinoplasty material was introduced from the United States in 1995, but its high price has affected its widespread application. In short, the selection of augmentation rhinoplasty materials should be based on their own conditions, economic conditions, combined with the diagnosis and prompt of doctors.