Hardrock Sandwich Technique (HST) — Bovine Pericardial Graft + Autologous Plasma Gel ± SLD ± Testicular Prosthesis
The Hardrock Sandwich Technique (HST) is a multicomponent penile-enlargement procedure that combines bovine pericardial grafts with autologous plasma gel for girth augmentation, plus suspensory-ligament division (SLD) and testicular-prosthesis placement for length and overall genital cosmesis. It is the largest single-center series in the penile-augmentation literature — Sertkaya 2025 n = 456 with ≥ 1-year follow-up — demonstrating +43.1% girth and +20.8% length increases with no reported sexual dysfunction.[1]
For the broader male cosmetic-genital-surgery decision framework see the Male Cosmetic Genital Surgery atlas page. For the SLD-only deep-dive see Suspensory Ligament Division. For the only FDA-cleared cosmetic device see Penuma & Himplant.
Concept and Rationale
The HST was designed to address the limitations of existing penile-augmentation techniques — specifically the resorption of fat grafts and HA fillers, the migration risk of injectable materials, and the infection / erosion risk of silicone implants. The technique derives its name from the "sandwich" layering of biological materials around the penile shaft.[1]
- Bovine pericardial grafts — durable, biocompatible extracellular-matrix scaffold with decades of safety data in Peyronie's-disease tunical-defect repair.[2][3][4]
- Autologous plasma gel — patient-derived; serves as a biological adhesive holding the pericardial grafts in position and as a bioactive growth-factor matrix (PDGF, TGF-β, VEGF, EGF) that promotes integration and angiogenesis.[1][5]
- The combination creates a layered construct — graft + plasma gel + graft — hence the "sandwich" configuration.
Surgical Components
The HST is a single-session combined procedure addressing both girth and length simultaneously through four distinct components.[1]
1. Girth augmentation — bovine pericardial graft + autologous plasma gel
- The penile shaft is degloved to expose the subcutaneous plane between the dartos fascia and Buck's fascia.
- Bovine pericardial grafts are shaped and placed circumferentially around the penile shaft.
- Autologous plasma gel is prepared from centrifuged venous blood and processed to a gel-like consistency, then applied between and over the graft layers.
- The "sandwich" layering creates a composite biological augmentation intended to integrate with native tissue over time, rather than remain as a permanent foreign body (Penuma) or resorb (HA filler).
2. Length augmentation — suspensory-ligament division
- Standard division of the suspensory ligament to allow anterior advancement of the intracorporeal penile shaft (see SLD for the deep-dive on technique, anti-retraction principles, and complication profile).
- Accounts for the +20.78% length increase (+2.17 cm) reported in the Sertkaya cohort.
3. Testicular prosthesis placement
- Placement of testicular prostheses as part of the overall genital aesthetic enhancement.
- A unique component not typically included in other penile-augmentation techniques; the explicit rationale is comprehensive genital cosmesis (penile and scrotal in a single session).
- The published series does not specify whether all 456 patients received testicular prostheses or only a subset.[1]
4. Combined single-session approach
- All components performed in one operative session, eliminating the need for staged procedures.
Materials — Bovine Pericardium
Bovine pericardium is a well-characterized biomaterial in urologic and reconstructive surgery, providing important context for its use in HST.[2][3][4][6][7]
Properties.
- Dense collagen-based extracellular matrix with excellent tensile strength.
- Biocompatible — serves as a scaffold for host-tissue ingrowth and remodeling.
- Available as commercially prepared, lyophilized, or glutaraldehyde-fixed products (Peri-Guard®, Hydrix®, Lyoplant®).
- Off-the-shelf availability eliminates donor-site morbidity.
Established urologic applications.
- Peyronie's disease — repair of tunical defects after plaque incision / excision. Otero 2017 lyophilized-bovine-pericardium series (n = 43) achieved complete penile straightening in 80.5% with 85% patient satisfaction and no rejection or infection. Choi 2021 H-shaped incision + bovine pericardium (n = 21) corrected curvature 70° → 5° (p < 0.001) at 1-yr Doppler follow-up.[3][4]
- Corporoplasty with prosthesis — bovine pericardium (Hydrix®) used to cover tunical defects during penile-prosthesis implantation with good functional outcomes (Zucchi 2013).[2]
- Animal models — rat tunical-substitution studies showed pericardial grafts allow complete penile expansion, withstand intracorporal pressures, and produce only minimal fibrosis at 6 months.[7]
Key advantage for HST. Unlike autologous grafts (saphenous vein, dermis, fascia lata), bovine pericardium requires no donor-site harvest — reducing operative time, morbidity, and complexity. Unlike synthetic materials (Gore-Tex), it shows minimal fibrosis and excellent biocompatibility.[6][7]
Autologous Plasma Gel
Related to but distinct from platelet-rich plasma (PRP).[1][5]
- Prepared from the patient's own venous blood through centrifugation and processing to a gel consistency.
- Contains concentrated growth factors (PDGF, TGF-β, VEGF, EGF) that promote tissue healing, angiogenesis, and cellular proliferation.
- Functions as both a biological adhesive holding the pericardial grafts in position and a bioactive matrix promoting graft integration.
- Autologous nature minimizes immunogenic and foreign-body reactions.
- PRP-based therapies have been explored in penile rejuvenation for ED and Peyronie's disease, with the first double-blinded RCT showing evidence of efficacy for ED.[5]
Efficacy Data
Sole published series — Sertkaya 2025 Int J Impot Res, n = 456, treated April 2022 – September 2024 at a single center.[1]
Dimensional outcomes
| Timepoint | Girth change | Length change |
|---|---|---|
| Postoperative day 1 | +43.13% (+4.51 ± 2.17 cm, p < 0.001) | +20.78% (+2.17 ± 2.53 cm, p < 0.001) |
| 3 months | Measured (specific values not reported in abstract) | Measured (specific values not reported in abstract) |
| 12 months | Measured (specific values not reported in abstract) | Measured (specific values not reported in abstract) |
Patient-reported outcomes at 1 year
Assessed using the APPSSI (Augmentation Phalloplasty Patient Selection and Satisfaction Inventory).[1]
- Satisfaction improvement: 83.4%
- Self-confidence improvement: 71.1%
- Self-esteem improvement: 75.3%
Functional outcomes
- No patients experienced erectile dysfunction.
- No patients experienced ejaculatory dysfunction.
Complications
Sertkaya 2025 cohort (n = 456).[1]
| Complication | Incidence | Management |
|---|---|---|
| Seroma | 6.12% (28/456) | Aspiration / conservative |
| Infection | 2.65% (12/456) | Antibiotic treatment |
| Wound dehiscence | 2.34% (11/456) | Wound care / revision |
| Hematoma | 1.40% (6/456) | Conservative / drainage |
| Skin necrosis (graft removal) | 0.22% (1/456) | Graft removal |
| Erectile dysfunction | 0% | — |
| Ejaculatory dysfunction | 0% | — |
Overall complication rate ~ 12.7% — comparable to the 14.6% pooled rate in the Vyas 2020 PRS aesthetic-augmentation-phalloplasty SR, with the notable distinction of zero sexual dysfunction.[1][8]
Comparison With Other Penile-Augmentation Techniques
| Feature | HST | Penuma silicone sleeve | HA filler | Autologous fat | PLGA scaffold + fibroblasts |
|---|---|---|---|---|---|
| Girth gain | +43.1% (+4.51 cm) | +56.7% (+4.9 cm) | +1.7–3.4 cm | +1.0 cm | +3.15 cm (mean) |
| Length gain | +20.8% (+2.17 cm) | +52% (+4.9 cm flaccid) | Minimal | None | None |
| Material | Biological (bovine pericardium + autologous plasma) | Synthetic (silicone elastomer) | Resorbable filler | Autologous fat | Autologous fibroblasts + PLGA |
| Tissue integration | Yes (scaffold remodeling) | No (permanent implant) | No (resorption) | Partial (variable survival) | Yes (neotissue formation) |
| Durability | Likely permanent (tissue integration) | Permanent while in situ | 12–18 months | Variable (20–80% resorption) | Permanent |
| Reversibility | Not easily reversible | Reversible (explant) | Reversible (hyaluronidase) | Not reversible | Not reversible |
| Complication rate | ~ 12.7% | 3–10% removal; seroma 4.8%, infection 2–3.3% | 5–14% (mild) | Variable | ~ 4.8% |
| Sexual dysfunction | 0% | 0% | 0% | Variable | 0% |
| n (largest study) | 456 | 400 | 38–50 | Variable | 204 |
Strengths
- Largest single-center series in the penile-augmentation literature (n = 456) — substantial dataset for a single technique.[1]
- Combined girth + length in a single procedure addressing both dimensions simultaneously.
- Biological materials only — no permanent synthetic implant remains in situ; the bovine pericardium acts as a scaffold for tissue remodeling, and the autologous plasma gel is the patient's own biological material.
- Zero sexual dysfunction reported — a critical safety metric.
- Relatively low complication rate (~ 12.7%) for a combined augmentation procedure vs the 14.6% pooled rate in the Vyas 2020 SR.[1][8]
- Leverages a well-established biomaterial — bovine pericardium has decades of safety data in urologic surgery.[2][3][4][6]
Limitations and Concerns
- Single-center, single-surgeon, retrospective study — highest risk of bias in the evidence hierarchy. Results have not been independently replicated.[1]
- Non-validated outcome instrument. APPSSI has not been validated — a limitation shared with the Penuma literature.[1][10]
- Limited long-term follow-up. Minimum 1 year, maximum ~ 2.5 years. The long-term fate of the bovine pericardial grafts in the subcutaneous penile space is unknown — pericardium integrates well in the tunical setting (Peyronie's disease), but its behavior in the subcutaneous space for cosmetic augmentation may differ.[1]
- POD-1 girth measurement may overestimate. The +43.1% girth gain was measured on POD 1, when surgical edema is maximal. The 3-month and 12-month values were measured but not reported in the abstract, so the degree of graft resorption or contraction over time cannot be assessed.[1]
- Testicular-prosthesis component is unexplained. The rationale for including testicular-prosthesis placement as part of a penile-augmentation procedure is not clearly articulated. It is unclear whether all 456 patients received testicular prostheses or only a subset.[1]
- No control arm, no comparator, no randomization.[1]
- Graft-based augmentation may negatively impact penile length in some series (Ramazan 2026 narrative review), although this was not observed in the HST cohort.[11]
- SMSNA 2024 position. All cosmetic penile-enhancement procedures, including graft-based techniques, are considered investigational with limited data. A multidisciplinary approach with mandatory psychological screening (BDDQ-AS / BDD-YBOCS) is required.[9]
- Reproducibility unknown. The technique has not been described in sufficient surgical detail for independent replication; no other centers have reported outcomes.[1]
Clinical Summary
The Hardrock Sandwich Technique represents an innovative biological approach to combined penile girth + length enhancement, using bovine pericardial grafts and autologous plasma gel as a "sandwich" construct, combined with suspensory-ligament division and testicular-prosthesis placement. The Sertkaya 2025 single-center series (n = 456) is promising — substantial girth gains (+43.1%), meaningful length gains (+20.8%), high satisfaction (83.4%), and zero sexual dysfunction. The evidence is, however, limited to a single retrospective series from one center, with a non-validated outcome instrument, potentially inflated POD-1 measurements, and insufficient long-term data on graft durability. Independent replication and prospective comparative studies are needed before HST can be recommended as a standard approach.[1][8][9][11]
See Also
- Male Cosmetic Genital Surgery (atlas)
- Suspensory Ligament Division
- Penuma & Himplant
- Hyaluronic Acid Filler
- Polylactic Acid Filler
- Suprapubic Lipectomy
- Penile Traction Therapy
- Small Penis Syndrome / PDD (clinical conditions)
- Foundations — Decellularized ECM
References
1. Sertkaya Z, Albayrak AT, Başağa Y, Sökmen D. A retrospective evaluation of the safety and effectiveness of an innovative penile-enlargement approach: the Hardrock Sandwich Technique. Int J Impot Res. 2025. doi:10.1038/s41443-025-01172-w
2. Zucchi A, Silvani M, Pecoraro S. Corporoplasty with small soft axial prostheses (VIRILIS I®) and bovine pericardial graft (HYDRIX®) in Peyronie's disease. Asian J Androl. 2013;15(2):275–279. doi:10.1038/aja.2012.156
3. Otero JR, Gómez BG, Polo JM, et al. Use of a lyophilized bovine pericardium graft to repair tunical defect in patients with Peyronie's disease: experience in a clinical setting. Asian J Androl. 2017;19(3):316–320. doi:10.4103/1008-682X.171572
4. Choi JB, Lee DS. Efficacy of H-shaped incision with bovine pericardial graft in Peyronie's disease: a 1-year follow-up using penile Doppler ultrasonography. Int J Impot Res. 2021;33(5):541–547. doi:10.1038/s41443-020-0312-y
5. Israeli JM, Lokeshwar SD, Efimenko IV, Masterson TA, Ramasamy R. The potential of platelet-rich plasma injections and stem cell therapy for penile rejuvenation. Int J Impot Res. 2022;34(4):375–382. doi:10.1038/s41443-021-00482-z
6. Kadioglu A, Sanli O, Akman T, et al. Graft materials in Peyronie's disease surgery: a comprehensive review. J Sex Med. 2007;4(3):581–595. doi:10.1111/j.1743-6109.2007.00461.x
7. Leungwattanakij S, Bivalacqua TJ, Yang DY, Hyun JS, Hellstrom WJ. Comparison of cadaveric pericardial, dermal, vein, and synthetic grafts for tunica albuginea substitution using a rat model. BJU Int. 2003;92(1):119–124. doi:10.1046/j.1464-410x.2003.04279.x
8. Vyas KS, Abu-Ghname A, Banuelos J, Morrison SD, Manrique O. Aesthetic augmentation phalloplasty: a systematic review of techniques and outcomes. Plast Reconstr Surg. 2020;146(5):995–1006. doi:10.1097/PRS.0000000000007249
9. Trost L, Watter DN, Carrier S, et al. Cosmetic penile-enhancement procedures: an SMSNA position statement. J Sex Med. 2024;21(6):573–578. doi:10.1093/jsxmed/qdae045
10. Elist JJ, Valenzuela R, Hillelsohn J, Feng T, Hosseini A. A single-surgeon retrospective and preliminary evaluation of the safety and effectiveness of the Penuma silicone-sleeve implant for elective cosmetic correction of the flaccid penis. J Sex Med. 2018;15(9):1216–1223. doi:10.1016/j.jsxm.2018.07.006
11. Ramazan M, Øbro LF, Wiborg MH, et al. Complications of penile augmentation: a narrative review of injectables, implants, and surgical grafts. Int J Impot Res. 2026;38(3):238–246. doi:10.1038/s41443-025-01190-8