Testicular implants are available in both fluid-filled and solid designs. Among these, solid implants offer several distinct advantages. Unlike saline-filled implants, solid silicone implants are permanent and do not risk failure or require replacement. They also provide a softer, more natural feel—an important feature given the thin soft tissue covering and the implant’s suspension between the thighs.
Silicone as a Material
Solid testicle implants are made of silicone, an inorganic synthetic polymer composed of polysiloxane chains (repeating silicon [Si] and oxygen [O] atoms). Silicone has unique physical properties that fall between synthetic rubber and plastic.
The softness of silicone is determined by a biomechanical test called a durometer, which measures how far a pin penetrates the material under a standard spring load. By manipulating polymer chain length (shorter) and crosslinking density (more entangled), manufacturers can produce silicone elastomers with greater softness. These advances explain why modern solid silicone testicular implants are significantly softer than those produced a decade ago.
Size and Firmness
Interestingly, implant size directly affects how soft it feels. As the implant becomes larger, even low-durometer silicone feels firmer simply because there is more material. For smaller implants (less than 5.0 cm or under 40 cc in volume), this difference is minimal. However, with larger implants, the increase in firmness becomes readily noticeable.
The Hollow Inner Chamber Innovation
To address this challenge, an innovative design incorporates a hollow inner chamber within the implant. This reduces the amount of material without altering the external shape, making the implant more compressible and consistently soft regardless of size.
The hollow chamber is created by introducing a small internal channel. Beyond reducing material, this design adds a valuable feature: it allows intraoperative placement of solutions directly into the implant. Most notably, antibiotics can be introduced into the chamber for gradual postoperative release, reducing the risk of infection. In effect, the implant doubles as a drug delivery system.
Universal Application
This hollow chamber design is effective across all implant sizes, which is why I prefer to use it even for smaller testicular implants.
Dr. Barry Eppley
World-Renowned Plastic Surgeon