Long-Term Safety and Longevity of a Mixture of Polymethyl Methacrylate and Cross-Linked Dextran (Lipen-10®) after Penile Augmentation: Extension Study from Six to 18 Months of Follow-Up

PURPOSE: The goal of this study was to investigate the long-term efficacy and safety of a mixture of polymethyl methacrylate (PMMA) and cross-linked dextran Lipen-10® used for penile augmentation under the physical impact generated during sexual intercourse. MATERIALS AND METHODS: From March 2010 to October 2011, a total of 20 patients with a mean age of 44 years (interquartile range, 20~70 years) who requested penile augmentation participated in this study. Lipen-10® filler is a mixture of 75% cross-linked dextran, 15% PMMA, and 10% hypromellose solution. With the patient in the supine position, Lipen-10® was injected into the subcutaneous tissue between the dartos fascia and Buck's fascia of the penis using a fanning technique. Penile length and circumference were measured before the procedure and six, 12, and 18 months after the procedure. Values were compared using the Student's t-test and the paired t-test. RESULTS: A total of 15 patients completed this study. The increases in circumference and length observed six months after the procedure were found to have been maintained without change at 12 and 18 months of follow-up. At 12 and 18 months of follow-up, no abnormal findings were observed. Pelvic magnetic resonance imaging conducted at 18 months of follow-up showed no trace of the injected filler having migrated to other sites, and the volume was well maintained. CONCLUSIONS: Lipen-10®, a mixture of PMMA and cross-linked dextran, showed good durability and tolerability over 18 months of follow-up during which the participants were sexually active.