Original ArticleClinical and Histologic Evaluation of a New Injectable Implant: Hydrophilic Polyacrylamide GelZhao, Yu MD, PhD*; Qiao, Qun MD, PhD†; Yue, Ying MD†; Kou, Xingcan MD†; Liu, Zhifei MD†Author Information From the *Division of Plastic and Reconstructive Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei; and the †Division of Plastic and Reconstructive Surgery, Plastic Surgery Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, China. Received November 17, 2003, and accepted for publication, after revision, January 5, 2004. Reprints: Yu Zhao, MD, PhD, Division of Plastic and Reconstructive Surgery, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, China. Email: [email protected] Annals of Plastic Surgery: September 2004 - Volume 53 - Issue 3 - p 267-272 doi: 10.1097/01.sap.0000120528.04016.48 Buy Metrics AbstractIn Brief Hydrophilic polyacrylamide gel is a new, jellylike transparent implant that consists of 95% water and 5% polyacrylamide, and it has been applied in many countries for many years as a sort of injectable implant. However, there are no data regarding human tissue reaction to hydrophilic polyacrylamide gel to date. Thirty-one patients who had undergone the injection of hydrophilic polyacrylamide gel for soft-tissue augmentation from September 1998 to November 2001 wanted to remove the implant. Hematoxylin–eosin-stained sections from each cyst of tissue sample were investigated and analyzed with light microcopy. The tissue slices of 12 patients who had received an injection of silicone from 1988 to 1994 were reviewed. The difference in histologic features was assessed. The inflammatory reaction of hydrophilic polyacrylamide gel was characterized by the presence of more foreign body giant cells. The cellular response ranged from moderate or marked (4 to 18 months) to mild (>18 months). The difference was statistically significant (P < 0.05). Little lymphocyte infiltration was shown in all slices of hydrophilic polyacrylamide gel. There were clusters or diffuse lymphocyte infiltration on histologic observation of the liquid silicone. The difference was significant (P < 0.001). In summary, hydrophilic polyacrylamide gel may evoke a human tissue inflammatory response similar to other foreign materials. Lumpy subcutaneous nodules, mastodynia, and difficult removal may limit its application in breast augmentation. Histological examination of electively-removed hydrophilic polyacrylamide gel implants from 31 patients demonstrated a greater inflammatory reaction than that surrounding previously-injected silicone liquid removed from 12 patients. © 2004 Lippincott Williams & Wilkins, Inc.