Himplant / Penuma — Subcutaneous Silicone Sleeve
Penuma and Himplant name a family of preformed silicone sleeves placed around the penile shaft, outside the corpora cavernosa. Penuma is the original device, and Himplant is described by its developer as a later iteration with a refined size matrix. Their cosmetic role differs from that of intracorporal prostheses, which provide erectile rigidity.[1] Older Penuma series report outcomes for earlier device generations and operative approaches.[1]
For the operative evidence and complications, see Penuma & Himplant.
Material and Regulatory Context
The May 2022 FDA 510(k) clearance (K220760, "Pre-Formed Penile Silicone Block") describes medical-grade silicone with an embedded polyester mesh, in one durometer ("Soft") and three sizes. Size L is 12 cm long, 0.5 cm thick and 2 cm high. Size XL is 15 cm, 0.8 cm and 3 cm. Size XXL is 18 cm, 1.1 cm and 3.5 cm. The surgeon may trim the block to fit the patient. The indication is augmentation, reconstructive and cosmetic surgery, and the summary states that augmentation use is for aesthetic purposes. The clearance rested on substantial equivalence to a predicate (K181387). Its clinical summary is a retrospective series of 400 of 526 men (those who responded to consent requests): midshaft circumference rose from a mean 8.5 to 13.4 cm, seroma occurred in 4.8%, scar formation in 4.5% and infection in 3.3%, and 3% had adverse events requiring removal.[2]
As described on the atlas page, the sleeve is crescent-shaped, with the ventral (urethral) side open. It lies in the subcutaneous plane between dartos and Buck fascia, external to the tunica albuginea, and does not enter the corpora cavernosa. It enlarges the flaccid penis and does not treat erectile dysfunction.
A solid silicone sleeve is also different from free liquid-silicone injection.[1]
Why Reconstructive Surgeons See These Devices
The devices are cosmetic, but patients with a sleeve in place are referred to reconstructive urologists for complications. These include extrusion or erosion through the skin, infection and abscess, migration or asymmetry, and distal flaring that produces a visible coronal ridge. Vascular or sensory compromise of shaft skin and dissatisfaction that leads to removal also occur. A referral-center series of 11 patients reported sexually disabling deformity, severe shortening and sexual dysfunction after genital-enlargement procedures that included subcutaneous implants.[3] It also included non-Penuma devices and injections.[3]
Comparison With Other Penile Devices and Foreign Bodies
| Feature | IPP | Penuma / Himplant | Free silicone (injected) | Penile pearls |
|---|---|---|---|---|
| Intent | Erectile function | Cosmetic girth | Cosmetic girth | Cosmetic or sexual stimulation |
| Material | Cured silicone elastomer | Cured silicone elastomer with polyester mesh | Liquid silicone | Beads or balls (variable) |
| Location | Intracorporeal | Subcutaneous shaft | Subcutaneous (variable) | Subcutaneous shaft |
| FDA-cleared for the penis | Yes | K220760 covers the specified preformed block for aesthetic augmentation; verify the exact model[2] | No | No |
| Removal | Explantation possible | Explantation possible; full reversal not assured | Very difficult | Surgical removal often required |
SMSNA Position and Counseling
The 2024 SMSNA position statement recommends silicone-sleeve implantation only under IRB oversight with long-term safety endpoints and no cost to the patient, by experienced surgeons after discussion of potentially severe complications. This is an expert-consensus recommendation reflecting limited and potentially biased evidence.[1]
Infection, erosion, extrusion, migration, distal flaring, deformity and dissatisfaction may lead to revision or removal. Published referral series document persistent shortening, curvature, sensory symptoms and erectile dysfunction after explantation.[1]
Removal and Subsequent Reconstruction
Surgical removal is possible; complete reversibility is not assured. Scarring, tissue adherence, infection and skin compromise determine the operative plan and whether staged management is required. The same distinction between explantation and full reversibility also applies to corporal penile prostheses.[1]
See Inflatable Penile Prosthesis, Penile Pearls and the Cosmetic Genital Surgery atlas.
References
1. Trost L, Khera M, Köhler T, et al. Cosmetic penile enhancement procedures: an SMSNA position statement. J Sex Med. 2024;21(6):573-578. doi:10.1093/jsxmed/qdae045.
2. FDA. Pre-Formed Penile Silicone Block, K220760. May 13, 2022. Clearance, indications and device summary.
3. Furr J, Hebert K, Wisenbaugh E, et al. Complications of Genital Enlargement Surgery. J Sex Med. 2018;15(12):1811-1817. doi:10.1016/j.jsxm.2018.10.007