Polyacrylamide hydrogel was introduced into China by Ukraine in 1997 as a medical soft tissue filling material, and its trade name was Ingelfahrer. 2000, the domestic hydrogel (Omnidene) gradually replaced Ingelfahrer as a soft tissue filling material, but these materials produced a large number of complications after injection. As a result, on April 30, 2006, the State Food and Drug Administration banned the production and use of this product on the grounds that “polyacrylamide hydrogel (for injection) is not safe for medical use”. The complications are as follows: hematoma, infection, traumatic aseptic inflammation, pectoralis major, sclerosis, breast asymmetry, gel displacement, play-doh-like changes, other rare complications such as menstrual breast swelling, nipple tingling, itching and abnormal sensation, mainly due to a small amount of gel entering the ducts or the tissue around the nipple, or diffuse sclerosis of the breast stimulating the nipple. As well as local color change, skin rash, menstrual cycle disorder, etc. Diagnostic and auxiliary examination means of Omniderm injection: In addition to history and physical signs, diagnostic puncture, combined with pathological examination, can clarify the diagnosis. Since polyacrylamide hydrogel is chemically inert, domestic and foreign scholars believe that MRI and ultrasound examination can meet the requirements of identifying the imaging data of the distribution of the material in the body, instead of choosing CT and breast infrared examination. Indications for surgical removal of Omnidene injection: 1.severe local pain and discomfort, affecting work, study and life; 2.deformation and hardening of the breast; 3.wandering displacement of the injected hydrogel; 4.serious mental burden due to fear of hydrogel toxicity and its side effects, affecting work and life; 5.local discomfort, foreign body sensation, itching, without other obvious reasons; 6.injection secondary infection 7.Local rupture, sinus tract formation; 8.Motor impairment of upper limbs and resting pain after injection. Indications for removal of Omnidine and implantation of prosthesis: 1. Good injection level, slight erosion of tissues, complete removal, clear anatomical level; 2. No infection or rupture of the breast; 3. Most of the injected material is in the posterior hiatus of the breast, granuloma invasion is limited to the breast, posterior hiatus of the breast, fascial surface of the pectoralis major muscle, and the pectoralis major muscle is basically intact; 4. have a certain thickness. Cases in which implants cannot be placed at the same time: 1. poor injection level and serious tissue erosion; 2. infection or ulceration; 3. injected material in or below the pectoralis major muscle, and serious damage to the pectoralis major muscle, which is confirmed by intraoperative investigation; 4. patients subjectively do not want to place implants at the same time. In the above cases, after the hydrogel is removed for six months, it will be decided whether the breast augmentation surgery can be done according to the recovery situation. Circumstances that can be considered for simultaneous implantation: 1.Multiple residual injections in breast tissue and or pectoralis major muscle tissue, which are hard and not soft to touch, but can be mostly removed by intraoperative investigation; 2.Thinner soft tissues after removal of injections, and patients who strongly request implant placement.