Inflatable penile prosthesis as tissue expander: what is the evidence?

Objective: Many patients who undergo inflatable penile prosthesis (IPP) replacement are often upsized to larger cylinders, suggesting the IPP may serve as a tissue expander and increase internal penile length. The objective of this study is to evaluate whether cylinder length increases with subsequent IPP insertion. Materials and Methods: We queried American Medical Systems and Coloplast Patient Information Form databases to identify patients who underwent IPP placement and replacement between 2004-2013. Patients were grouped by device type and time to replacement (<2 or >= 2 years). We selected the 2-year mark for subgroup analysis to allow time for tissue expansion to occur and to exclude patients who underwent early explantation (e.g. erosion or infection). Results: Two thousand, seven hundred and forty nine patients (1,532 AMS 700 LGX, 717 AMS 700 CX, and 500 Coloplast Titan) met the inclusion criteria. Mean time between implants was earlier for LGX (29 months) than CX (39 months) and Titan (48 months) patients (p< 0.001). Patients who underwent device replacement at < 2 years did not experience an increase in mean cylinder length. On the contrary, patients who underwent device replacement at >= 2 years did experience significant increases in mean cylinder length (LGX 1.2 cm, CX 1.1 cm, and Titan 0.9 cm, p< 0.001). The mean increases in length at >= 2 years were similar between the 3 devices (p= 0.20). Sixty percent of patients demonstrated increases of > 0.5 cm and 40% demonstrated increases of >= 1 cm. Conclusions: As demonstrated, the IPP may provide tissue expansion over time. Further evaluation is needed to determine if increased cylinder length correlates to increased functional length and patient satisfaction.