Anatomical Context
The penile shaft comprises several concentric fascial layers that are surgically relevant to implant placement. The outermost layer is the skin and the immediately subjacent dartos fascia — a thin layer of smooth muscle and areolar tissue continuous with the scrotal dartos. Deep to this lies Buck's fascia (deep fascia of the penis), a dense fibrous envelope that surrounds the corpora cavernosa and corpus spongiosum. Between the dartos fascia and Buck's fascia exists the sub-dartos plane — a tissue plane with minimal vascularity and neural density that serves as the implantation site for FDA-cleared silicone devices.
The corpora cavernosa are the paired erectile chambers occupying the dorsolateral aspect of the penile shaft. They are enclosed within the tunica albuginea, a thick fibrous coat that provides structural rigidity during erection. Placement of the silicone sleeve in the sub-dartos plane, superficial to Buck's fascia and the underlying corpora, preserves the neurovascular bundle and native erectile architecture entirely. The dorsal neurovascular bundle — containing the deep dorsal vein, paired dorsal arteries, and dorsal nerves — runs within Buck's fascia and is not accessed during sub-dartos implantation.
Understanding this anatomy clarifies why sub-dartos silicone implantation does not affect erectile function: the device occupies the fascial space superficial to the corpora, adding circumferential soft tissue volume without entering or compressing the erectile chambers or neurovascular supply.
What the Procedure Involves
The procedure is performed under general or spinal anaesthesia in an outpatient surgical setting. The patient is positioned supine. A penoscrotal or penopreputial incision — typically 2–4 cm — provides access to the sub-dartos plane. The surgeon develops the plane circumferentially around the shaft using gentle blunt dissection, creating a uniform pocket between Buck's fascia and the overlying dartos. Haemostasis is achieved meticulously because any haematoma within this confined space risks implant displacement or infection.
Intraoperative sizers — temporary trial implants of increasing diameter — are placed sequentially to determine the optimal device size for the individual anatomy. The Himplant and Penuma are the two FDA-cleared solid silicone sleeve devices currently available. Both are composed of medical-grade solid silicone configured as a cylinder or sleeve designed to wrap circumferentially around the penile shaft within the sub-dartos pocket. Once the appropriate size is confirmed, the definitive implant is placed, its position is verified, and the incision is closed in layers using absorbable sutures. A compression dressing is applied at the conclusion of the case.
The total operative time is typically 45 to 75 minutes, with patients discharged to home the same day following a brief recovery room observation period. Both the Himplant (Himplant, Inc.) and the Penuma (Geselowitz Corp.) have received FDA 510(k) clearance for subcutaneous placement in the sub-dartos plane.
Candidacy Criteria
Ideal candidates are adult males with adequate baseline penile dimensions — specifically a minimum erect length of approximately 12 cm — necessary for appropriate implant sizing and fit. Candidates should have no active penile or scrotal infection, no untreated coagulopathy, and no concurrent indication for an inflatable penile prosthesis (IPP). Men with severe erectile dysfunction requiring IPP implantation are not suitable for silicone sleeve implantation, as the procedures involve incompatible anatomical approaches. Candidates must have a realistic understanding that the procedure addresses circumferential girth in both the flaccid and erect state, and does not reliably increase erect length.
Contraindications include active penile, scrotal, or inguinal infection; baseline penile dimensions below the threshold required for proper sleeve sizing; prior penile surgery creating significant sub-dartos scarring that would prevent uniform pocket creation; and concurrent radical prostatectomy planning (in such cases, IPP implantation should be staged appropriately). Patients with significant prepubic fat accumulation may benefit from concurrent pubic liposuction to optimise the aesthetic result, and this combination can be discussed at the preoperative consultation.
Recovery Timeline
Immediately following surgery, a compression wrap is applied to the penile shaft and maintained for 48 to 72 hours to minimise oedema and reduce the risk of haematoma formation. Patients are ambulatory the same day and typically experience mild-to-moderate discomfort managed adequately with oral analgesics. The compression dressing is removed at the first post-operative visit. Moderate penile swelling and ecchymosis are expected and peak at 48–72 hours before subsiding progressively.
Patients working sedentary or desk-based roles generally return to work within 5 to 7 days. Strenuous physical activity, heavy lifting, and prolonged lower-extremity exertion are restricted for 4 weeks to prevent implant migration during the early integration phase. Sexual activity — including both masturbation and intercourse — is restricted until 6 to 8 weeks post-operatively and cleared specifically at a surgeon examination, not by calendar date alone. Final aesthetic assessment of implant position and integration is conducted at the 3-month follow-up, when residual oedema has fully resolved.
Risks and Complication Profile
As with all surgical implant procedures, the silicone penile implant carries device-specific and procedure-specific risks. Infection occurs in approximately 1 to 3% of cases and may necessitate device removal if not controllable with antibiotics. Implant migration — displacement of the device from its intended sub-dartos position — can occur if pocket creation is not uniform or if post-operative activity restrictions are not observed. Sizing dissatisfaction is a patient-experience risk: intraoperative sizers simulate but cannot perfectly replicate the final healed result, and some patients find the selected size aesthetically suboptimal.
Additional reported complications include wound dehiscence (particularly at the penoscrotal incision, where tension is present), asymmetry from non-uniform pocket development, and — rarely — altered penile skin sensation. Revision surgery rates in high-volume centres for properly selected patients are reported at approximately 5 to 10%. Device explantation rates vary by centre and patient population but average approximately 5% in published series.
Cost Considerations
The total cost of $15,000 to $25,000 incorporates four primary components: the surgeon's professional fee, the outpatient surgical facility fee, the anaesthesia fee, and the implant device cost. The device itself — whether Himplant or Penuma — carries a substantial per-unit cost that accounts for a meaningful fraction of the total. Unlike pharmaceutical therapeutics or off-the-shelf instruments, each device is customised or sized to the individual patient at the time of surgery.
This procedure is categorically aesthetic in indication and is not covered by any private or government insurance payer. Payment is cash-pay or patient-financed. Patients should obtain a comprehensive itemised cost estimate — including the specific device to be used and its size — prior to committing, and should clarify whether the quoted fee includes follow-up visits, compression garments, and any revision within a defined post-operative period.
Selecting a Qualified Surgeon
Silicone penile implantation requires a surgeon with specific training in genital anatomy, sub-dartos plane dissection, and implant sizing. The procedure is not within the standard scope of general urological or plastic surgical training. Candidates should seek a surgeon holding active board certification through the American Board of Urology (ABU), active membership in the Sexual Medicine Society of North America (SMSNA), and — ideally — documented completion of an andrology or sexual medicine fellowship. Certification alone does not establish procedural competence; patients should ask directly about the surgeon's case volume with this specific device and their revision and infection rates.
Surgeons who are certified trainers or proctors for the Himplant or Penuma device have typically demonstrated minimum volume requirements set by the manufacturer and have undergone hands-on device-specific training. This credential, while not the only marker of quality, is a useful proxy for procedural experience in the context of this specific implant category.