What does a penile prosthesis look like?

Penile Prosthesis Types and Appearance

Penile prostheses are mechanical devices implanted within the corpora cavernosa that provide rigidity for sexual intercourse in men with erectile dysfunction who have failed or cannot use less invasive treatments. 1

Types of Penile Prostheses

Malleable (Non-Inflatable) Prostheses

• Consist of paired semi-rigid rods implanted into each corpus cavernosum 1
• Maintain constant rigidity but can be bent into different positions 1
• Appear as hypointense structures on T1- and T2-weighted MRI 2
• Advantages include lower cost, better mechanical reliability, and ease of use without requiring patient training 3, 1
• Disadvantages include cosmetic concerns as the semi-rigid devices protrude when not in use 3

Inflatable Penile Prostheses (IPPs)

• Provide a more natural appearance in both flaccid and erect states 1
• Two main types: two-piece and three-piece designs 1, 4
• Three-piece IPPs (most common design):
  • Paired cylinders implanted in the corpora cavernosa 1
  • Scrotal pump for inflation/deflation 1
  • Fluid reservoir positioned in the abdomen 1
• Appear on MRI as homogeneously T2 hyperintense cylinders with T2 hypointense silicone-based covering 2
• Advantages include high technical success rates and patient satisfaction (80%) 3
• Modern designs feature lockout valves to prevent auto-inflation, reducing rates from 11% to 1.3% 3

Design Innovations

• Antibiotic coatings (rifampin and minocycline) have reduced infection rates from 1.61% to 0.68% 3
• Hydrophilic coatings that can be immersed in antibiotics pre-operatively have reduced infection rates from 2.07% to 1.06% 3
• All current penile implants are MRI compatible at 1.5 Tesla field strength 3, 1
• Mechanical failure rates have decreased to 6-16% at 5 years with modern designs 1, 5

Special Considerations

• Inflatable penile prostheses are recommended for patients with Peyronie's disease as they allow for modeling to maximize curvature correction 3, 6
• For patients with acute ischemic priapism lasting >36 hours, penile prosthesis placement may be considered to provide detumescence and preserve penile length 3
• Patients must understand that prosthesis implantation will likely reduce the efficacy of subsequent therapies should they be needed 3, 6

Potential Complications

• Infection remains the most serious complication (rates now 1-2% with coated devices) 3, 1
• Mechanical failure can occur but is less common with modern designs 1
• Other complications include erosion, migration, penile shortening, and changes in sensation 3, 5
• Perineal pain can persist for 1-2 months after implantation 3

Emerging Technologies

• Novel shape memory alloy prostheses activated by magnetic induction are being developed as alternatives to hydraulic-based systems 7
• These eliminate the need for reservoirs and pumps, potentially making the devices easier to use 7

The choice between malleable and inflatable prostheses should be based on patient factors including manual dexterity, anatomical considerations, and personal preference, with three-piece inflatable devices generally considered the gold standard in advanced economies 8.