A Comparison Between Hyaluronic Acid and Polylactic Acid Filler Injections for Temporary Penile Augmentation in Patients with Small Penis Syndrome: A Multicenter, Patient/Evaluator-Blind, Comparative, Randomized Trial

Abstract Introduction There are only a few studies on the clinical utility of filler injections for penile augmentation (PA) in patients with small penis syndrome (SPS), which is a type of anxiety or body dysmorphic disorder, not a true micropenis. Aim To compare the clinical outcomes of hyaluronic acid (HA) with polylactic acid (PLA) filler injection for temporary PA in patients with SPS. Methods Our prospective, patient/evaluator-blind, comparative, randomized, non-inferiority trial consisted of a single filler injection and a 24-week post-injection period. Seventy-four men with SPS were included between November 2017 and February 2018. Patients were divided into those injected with HA (n = 39) and those injected with PLA filler (n = 35). Main Outcome Measure The psychological effects of PA, based on the Beliefs about Penis Size Scale, penile girth, and satisfaction, were assessed at baseline and at 4, 12, and 24 weeks post-injection. Results At 24 weeks, the mean penile girth increases were 2.1 ± 1.0 cm (P < .001) in the HA group and 1.6 ± 0.9 cm (P < .001) in the PLA group, with a mean difference of 0.5 ± 0.2 cm between groups (P = .031). In both groups, satisfaction levels significantly increased at 24 weeks, with 1.8 ± 1.7 and 1.6 ± 1.4 mean increases in the visual analog scale for penile appearance satisfaction in the HA and PLA groups, respectively (each P < .001), and 1.0 ± 1.1 and 0.7 ± 1.2 mean increases in the visual analog scale for sexual life satisfaction in the HA and PLA groups, respectively (each P < .001), with no significant differences between groups (P = .950 and P = .287). The mean Beliefs about Penis Size Scale scores significantly decreased at 24 weeks, with 7.8 ± 8.3 and 5.3 ± 7.2 mean decreases in the HA and PLA groups, respectively (each P < .001), and no significant difference between the groups (P = .920). There were no serious adverse events, but filler injection-related adverse events in the HA and the PLA groups were reported in 2 cases (5.13%) and 5 cases (14.29%), respectively (P = .245). Clinical Implications Our study provides an overview of clinical course after HA and PLA filler injections for PA and suggests that filler injections can be considered an alternative approach in patients with SPS. Strengths & Limitations Our study is the first to assess the psychological symptoms in patients with SPS who received the filler injection for PA; however, the follow-up duration was insufficient to prove the long-term outcomes of fillers. Conclusion Without serious adverse events, HA and PLA filler injections for PA significantly resulted in not only an augmentative effect but also improvement of psychological distress, and the clinical utility was comparable between the fillers.