Templated Auxetic Tunical Expansion With a Malleable Penile Prosthesis for Complex Peyronie Disease

Moeda ASG, Ambar RF, Amin EC, Gorga CFA, Reis AKS, Bertero EB

Peyronie disease; penile prosthesis; auxetic technique; tunica albuginea; penile lengthening; malleable implant

Penile prosthesis implantation is the definitive treatment for Peyronie disease (PD) with refractory erectile dysfunction, but residual curvature and penile shortening remain major concerns. Conventional relaxing incisions correct curvature while producing perpendicular narrowing, and grafting large tunical defects under a nonsutured patch risks cylinder herniation. The auxetic technique uses small star-shaped tunical incisions placed with a geometric template; behaving as an auxetic material (negative Poisson ratio), they expand length and girth simultaneously without a graft. This video shows the technique in a 67-year-old man with type 2 diabetes and Parkinson disease who presented with a 1-year history of dorsal penile curvature, moderate erectile dysfunction, reduced elasticity, and significant retraction, with a 1.5-cm dorsal plaque in the mid-to-distal shaft. Under pharmacologically induced erection with intracavernous trimix, hardness reached an Erection Hardness Score of 3; penile duplex ultrasound showed borderline arterial inflow (peak systolic velocity 26 cm/s right, 31 cm/s left) and no veno-occlusive dysfunction (end-diastolic velocity −6.39 and −6.30 cm/s). Limited manual dexterity contraindicated an inflatable device, so a malleable prosthesis was selected. The video covers degloving, artificial erection, mapping of the dorsal plaque, template-guided star-shaped (auxetic) tunical incisions, corporotomy and dilation, and implantation of Genesis malleable rods (19.5 cm × 11 mm; Coloplast, Minneapolis, MN), which tamponade the auxetic defects without grafting. Curvature was completely corrected with no residual deformity, and stretched penile length increased from 12.5 cm preoperatively to 15.0 cm postoperatively (a 2.5-cm gain). Recovery was uneventful and the correction was maintained at the 1-month follow-up; longer-term follow-up is ongoing. Templated auxetic tunical expansion combined with a malleable prosthesis is a feasible, graftless, single-stage option to correct curvature and restore length in complex PD, particularly when an inflatable device is impractical.

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