Malleable Penile Prosthesis (MPP)
The malleable penile prosthesis is a non-inflatable device consisting of paired semi-rigid rods implanted into the corpora cavernosa. The rods can be bent manually for concealment or positioning and hold their shape until repositioned.
Devices
- AMS Spectra (Boston Scientific)
- Coloplast Genesis — hydrophilic-coated variant
- Rigi-Flex, Subrini, Stella — international variants
Design
- Silicone-coated solid core with an internal metal wire (typically silver or stainless steel braided)
- Trimmable to length
- Surface finish for tissue integration and infection resistance
Indications — When Malleable vs Inflatable
Favor malleable in:
- Patients with limited manual dexterity — arthritis, stroke, spinal cord injury with limited hand function
- Revision / salvage after IPP explant for infection with scarred corpora
- Phalloplasty prosthesis implantation where cylinder elongation against a neourethra is difficult
- Simpler operation when 3-piece reservoir placement is undesirable
- Cost constraints — lower device cost, faster operation
Favor inflatable in:
- Standard ED with intact dexterity
- Cosmetic concealment important (flaccid state)
- Concerns about pressure atrophy of corporal tissue against permanent rigidity
Trade-offs
| Feature | Malleable | Inflatable |
|---|---|---|
| Cost | Lower | Higher |
| Operation time | Shorter | Longer |
| Dexterity needed | Minimal | Moderate |
| Cosmetic (flaccid) | Always partially rigid | Natural flaccidity |
| Revision complexity | Lower | Higher |
| Long-term durability | Very high | Mechanical failure possible |
See also: Inflatable Penile Prosthesis.