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Hardrock Sandwich Technique (HST) — Bovine Pericardial Graft + Autologous Plasma Gel ± SLD ± Testicular Prosthesis

The Hardrock Sandwich Technique (HST) combines bovine pericardial grafts and autologous plasma gel for penile girth augmentation with suspensory-ligament division and placement of a silicone prosthesis fragment at the pubic bone as a spacer for apparent length gain.[12] The journal report describes a single-center retrospective cohort of 456 men with at least one year of follow-up. An earlier abstract called the same-date series multicenter and reported 740 treated, of whom only 105 had one-year follow-up; the later journal abstract calls it single-center and reports 456 with at least one-year follow-up. The center and denominator differences are unexplained.[1][15] The later 456-patient journal report found girth +43.1% and length +20.8% on postoperative day 1; no erectile or ejaculatory dysfunction was reported in that retrospective cohort.[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 an FDA-cleared cosmetic penile implant see Penuma & Himplant.[10][20]

Concept and Rationale​

The authors present HST as an alternative to fat grafts, HA fillers, and silicone sleeves, citing resorption, migration, and infection risks with established approaches. HST retains a silicone spacer at the pubic bone, and comparative reductions in infection, erosion, or migration have not been shown.[1][12][9] The name comes from the "sandwich" layering of biological materials around the penile shaft.[1]

  • Bovine pericardial grafts. Biocompatible extracellular-matrix scaffold with satisfactory mid-term outcomes in Peyronie's-disease tunical-defect repair; longer follow-up is lacking.[6][2][3][4]
  • Autologous plasma gel. Patient-derived gel is placed between the pericardial graft layers and may help hold them together.[12] Growth-factor-mediated tissue ingrowth is a proposed role, but HST has not measured gel growth factors, graft integration, or angiogenesis.[5][1]
  • 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​

  • In the authors' video, a reverse V incision 2–3 cm above the penile base under general anesthesia precedes dissection to Buck's fascia and reverse degloving between dartos and Buck's fascia. Penile intussusception provides distal subdermal access.[12]
  • Bovine pericardial grafts are shaped and wrapped circumferentially around the shaft, secured distally at the coronal sulcus, and affixed to the tunica albuginea with absorbable sutures. The authors' video describes reapproximation of the dartos and Buck's fasciae, proximal V-Y skin advancement, Jackson-Pratt drain removal when output is <20 mL/day, and abstinence from sexual activity and masturbation for at least six weeks or until cleared.[12]
  • 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. A silicone implant (Penuma) remains as a permanent foreign body and HA filler resorbs.

2. Length augmentation — suspensory-ligament division​

  • The suspensory ligament is divided to increase exposure of the shaft and apparent flaccid length (see SLD for technique, anti-retraction principles, and complications).[9][16]
  • Ligament release and the pubic-bone spacer were combined in the cohort reporting a +20.78% day-1 length change (+2.17 cm); their separate contributions were not measured.[1][17]

3. Pubic-bone spacer fashioned from a testicular prosthesis​

  • In the authors’ operative video, a cut silicone testicular prosthesis is anchored to the pubic bone after suspensory-ligament division to serve as a spacer and bridge.[13]

4. Combined single-session approach​

  • The reported components were performed in one operative session, without a staged procedure.[15]

Materials — Bovine Pericardium​

Bovine pericardium is used as a graft in urologic and reconstructive surgery, mainly for tunical defects in Peyronie's disease.[2][3][4][6][7]

Properties.

  • Dense collagen-based extracellular matrix with tensile strength.
  • Biocompatible; serves as a scaffold for host-tissue ingrowth and remodeling.
  • The HST video specifies two Tutopatch® bovine-pericardial layers.[12] Peri-Guard® (lyophilized) and Hydrix® have been described for separate Peyronie's tunical-repair procedures.[3][2]
  • Off-the-shelf availability avoids donor-site harvest for the pericardial graft.[3]

Established urologic applications.

  • Peyronie's disease. Repair of tunical defects after plaque incision or excision. In the Otero 2017 lyophilized-bovine-pericardium series (n = 43, 41 with follow-up, mean 14 months), complete straightening was achieved in 80.5% and 85% of patients were satisfied, with no rejection or infection.[3] In the Choi 2021 retrospective series of H-shaped incision and bovine pericardium (n = 21), median erect curvature fell from 70° to 5° (p < 0.001) at 1 year.[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. In a 100-rat tunical-substitution study, 20 rats received cadaveric pericardial grafts, which allowed complete penile expansion and withstood intracorporal pressures. Fibrosis was moderate at 4 months and minimal at 6 months.[7]

Advantage for HST. Bovine pericardium avoids autologous graft harvest and its donor-site morbidity.[1][3] In the rat model, Gore-Tex grafts caused moderate fibrosis at 6 months, whereas pericardium caused minimal fibrosis.[6][7]

Autologous Plasma Gel​

Autologous plasma gel is 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.
  • Proposed to help hold the pericardial layers together and support tissue ingrowth; these effects remain unmeasured in HST.[12][1]
  • Autologous nature minimizes immunogenic and foreign-body reactions.
  • PRP injections have been studied for erectile dysfunction and Peyronie's disease. An early double-blind ED trial reported efficacy.[5] A later placebo-controlled trial in 61 men found no between-group difference in the 1-month minimum-clinically-important-difference response (14/24 PRP versus 15/28 placebo).[25]

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​

TimepointGirth changeLength change
Postoperative day 1+43.13% (+4.51 ± 2.17 cm, p < 0.001)+20.78% (+2.17 ± 2.53 cm, p < 0.001)[1]
3 monthsMeasured; values not reportedMeasured; values not reported
12 monthsMeasured; values not reportedMeasured; values not reported

Patient-reported outcomes at 1 year​

Assessed using the APPSSI (Augmentation Phalloplasty Patient Selection and Satisfaction Inventory).[1]

  • Satisfaction improvement at 1 year: 83.4%[1]
  • Self-confidence improvement at 1 year: 71.1%[1]
  • Self-esteem improvement at 1 year: 75.3%[1]

Functional outcomes​

  • No patients experienced erectile dysfunction.
  • No patients experienced ejaculatory dysfunction.

Complications​

Sertkaya 2025 cohort (n = 456).[1]

ComplicationIncidenceManagement
Seroma6.12%Aspiration / conservative
Infection2.65%Antibiotic treatment
Wound dehiscence2.34%Wound care / revision
Hematoma1.40%Conservative / drainage
Skin necrosis (graft removal)0.22% (1/456)Graft removal
Erectile dysfunction0%—
Ejaculatory dysfunction0%—

The five reported HST event percentages sum to approximately 12.7%, but the number of patients with any complication is not reported.[1] The HST event sum cannot be compared as a patient-level rate with the 14.6% pooled rate in the Vyas 2020 review of 16 heterogeneous, methodologically weak studies (1,192 patients).[1][8] No erectile or ejaculatory dysfunction was reported in the HST cohort.[1] Complications were reported across other augmentation methods in the Vyas 2020 review.[8] For HST's suspensory-ligament-division component, SMSNA advises counseling about possible erectile dysfunction, sensory changes, and penile instability.[9]

Comparison With Other Penile-Augmentation Techniques​

FeatureHSTPenuma silicone sleeveHA fillerAutologous fatPLGA scaffold + fibroblasts
Girth gain+43.1% (+4.51 cm) on day 1[1]+56.7% (+4.9 cm) at 30–90 days in 400 consenters[10]+2.66 cm at 1 month; +1.80 cm at 6 months in 230 patients[18]EAU 2026: mean +2 to +3.5 cm circumference in retrospective fat-injection series (follow-up and measurement state vary).[16]+3.15 cm mean in 84 of 204 treated (median follow-up 24 months)[21]
Length gain+20.8% (+2.17 cm) on day 1[1]+52% flaccid (mean 8.1 to 12.3 cm) in a separate 49-patient series with mean 6-month follow-up[22]+2.55 cm flaccid at 1 month; +1.65 cm at 12 months in 38 patients[23]+0.6 cm flaccid and +0.4 cm erect at 12 months in one 38-man Coleman-fat cohort.[26]None
MaterialBovine pericardium + autologous plasma gel; silicone pubic-bone spacer[14]Synthetic (silicone elastomer)Resorbable fillerAutologous fatAutologous fibroblasts + PLGA
Tissue integrationNot demonstrated in reported HST outcomes[1]No (permanent implant)No (resorption)Partial (variable survival)Tissue-engineering intent[21]
DurabilityNot established for HST; day-1 dimensions reported, with at least 1-year clinical follow-up[1]Permanent while in situIn one trial, mean HA girth gain declined from +2.50 cm at 1 month to +1.41 cm at 18 months (33 assigned HA; 46/67 overall retained at 18 months).[27]Variable; a review cites 20–80% fat-volume loss during the first year.[28]1–5-year follow-up in 84/204; permanence not established[21]
ReversibilityNot easily reversibleImplant can be removed, but penile shortening or curvature has been reported after explantation.[9]Reversible (hyaluronidase)Not reversibleNot reversible
Complication rateAny-complication patient rate not reported; event percentages total 12.7%[1]In 400 consenters: removal 3%, seroma 4.8%, infection 3.3%[10]4.3% with a complication over 6 months (n = 230)[18]VariableReported events: infection 3, skin necrosis 2, seroma 5; 204 treated, 84 followed 1–5 years[21]
Sexual dysfunctionNo erectile or ejaculatory events reported (n = 456)[1]No change in sexual function reported among 400 consenters[10]Not reported as a rate in the cited 230-patient HA study[18]VariableNot reported as a rate in the cited scaffold study[21]
n (cited girth study)456400230 (Quan 2021; 6-month follow-up)[18]Variable204

Strengths​

  • The series is large for a single technique (n = 456, ≥ 1-year follow-up).[1]
  • Girth and length are addressed in a single procedure.
  • Bovine pericardium and autologous plasma gel form the shaft graft; a silicone prosthesis fragment remains at the pubic bone as a spacer.[19][1]
  • No erectile or ejaculatory dysfunction was reported.
  • HST event types are reported separately; the number of patients with any complication is not given. Vyas 2020 pooled a 14.6% complication rate across other augmentation methods, with the highest rate after combined procedures.[1][8]
  • Bovine pericardium has been used in Peyronie's-disease grafting with satisfactory mid-term results.[2][3][4][6]

Limitations and Concerns​

  • Single-center, single-surgeon, retrospective study. This design carries a high risk of bias.[1]
  • Non-validated outcome instrument. APPSSI has not been validated.[1]
  • Limited long-term follow-up. Minimum follow-up was 1 year. 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 postoperative edema may contribute to the measurement.[1] The 3-month and 12-month values are not reported.[1]
  • Testicular-prosthesis component is incompletely reported. The operative video describes a quarter-prosthesis pubic-bone spacer after ligament release, while an earlier abstract describes a half-prosthesis. The 456-patient report gives neither a component-level denominator nor a separate spacer outcome.[12][15][1]
  • No control arm, no comparator, no randomization.[1]
  • Graft-based augmentation has been associated with reduced penile length in retrospective series (Ramazan 2026 narrative review).[11]
  • Society positions. SMSNA 2024 advises against graft-and-flap penile augmentation outside a research protocol until more outcome data are available and calls for penile dysmorphic disorder screening before invasive enhancement, using the Body Dysmorphic Disorder Symptom Scale or Questionnaire with professional psychological assessment.[9] EAU 2026 strongly recommends against grafts, biodegradable scaffolds, and subcutaneous Penuma implants for penile girth enhancement because it considers these approaches experimental.[16] BAUS AGUS 2026 also recommends against elective surgical penile augmentation because high-quality supporting evidence is lacking.[24]
  • No other centers have reported outcomes.[1]

Clinical Summary​

The Hardrock Sandwich Technique combines a bovine-pericardial and autologous-plasma-gel shaft construct with suspensory-ligament division and a retained silicone prosthesis fragment anchored at the pubic bone.[19] The Sertkaya 2025 single-center series (n = 456) reported girth gain of 43.1% and length gain of 20.8% on POD 1, satisfaction improvement in 83.4% at 1 year, and no erectile or ejaculatory dysfunction.[1] The evidence is a single retrospective series from one center, with a non-validated outcome instrument, POD-1 measurements that may include edema, and no long-term data on graft durability.[1] SMSNA recommends against graft-and-flap augmentation until further outcome data are available.[9]

See Also​

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, 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

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

12. Sertkaya Z, Albayrak AT, Başağa Y, Sökmen D. "An innovative penile enlargement approach: the Hardrock Sandwich Technique." VJSM. 2025;1:182. Video

13. Sertkaya Z, Albayrak AT, Başağa Y, Sökmen D. "An innovative penile enlargement approach: the Hardrock Sandwich Technique." VJSM. 2025;1:182. Video

14. Sertkaya Z, Albayrak AT, Başağa Y, Sökmen D. "An innovative penile enlargement approach: the Hardrock Sandwich Technique." VJSM. 2025;1:182. Video

15. Sertkaya Z, Sökmen D, Albayrak AT, Başağa Y. "A multi-center, retrospective evaluation of the safety and effectiveness of the Hardrock Sandwich Technique for elective penile enlargement surgery." J Sex Med. 2025;22(Suppl 2):qdaf077.232. doi:10.1093/jsxmed/qdaf077.232

16. European Association of Urology. EAU Guidelines on Sexual and Reproductive Health. 2026. Section 9.3.2.d.4. Guideline

17. Sertkaya Z, Albayrak AT, Başağa Y, Sökmen D. "An innovative penile enlargement approach: the Hardrock Sandwich Technique." VJSM. 2025;1:182. Video

18. Quan Y, Gao ZR, Dai X, et al. "Complications and management of penile augmentation with hyaluronic acid injection." Asian J Androl. 2021;23(4):392-395. doi:10.4103/aja.aja_78_20

19. Sertkaya Z, Albayrak AT, Başağa Y, Sökmen D. "An innovative penile enlargement approach: the Hardrock Sandwich Technique." VJSM. 2025;1:182. Video

20. U.S. Food and Drug Administration. "510(k) Summary: Pre-Formed Penile Silicone Block." 2022. K220760

21. Perovic SV, et al. "New perspectives of penile enhancement surgery: tissue engineering with biodegradable scaffolds." Eur Urol. 2006;49(1):139-147. doi:10.1016/j.eururo.2005.08.016

22. Siegal AR, et al. "Outcomes of a Single Center’s Initial Experience With the Penuma Penile Implant." Urology. 2023;171:236-243. doi:10.1016/j.urology.2022.07.066

23. Zhang CL, et al. "Penile augmentation with injectable hyaluronic acid gel: an alternative choice for small penis syndrome." Asian J Androl. 2022;24(6):601-606. doi:10.4103/aja20223

24. Mubarak M, Kalejaiye O, Kumar V, et al. "British Association of Urological Surgeons (BAUS) consensus document on male genital augmentation and enhancement procedures." J Clin Urol. 2026;19(2):149–166. doi:10.1177/20514158251391054

25. Masterson TA, Molina M, Ledesma B, et al. "Platelet Rich Plasma for the Treatment of Erectile Dysfunction: A Prospective, Randomized, Double-Blind, Placebo-Controlled Clinical Trial." J Urol. 2023;210(1):154–161. doi:10.1097/JU.0000000000003481

26. Ivanenko O, Gheiler E, Sforza M. "Superior penile girth retention with stromal vascular fraction-enriched autologous fat grafting: a retrospective 1-year comparative study." Transl Androl Urol. 2026;15(7):244. doi:10.21037/tau-2026-0415

27. Yang DY, Jeong HC, Ko K, Lee SH, Lee YG, Lee WK. "Comparison of Clinical Outcomes between Hyaluronic and Polylactic Acid Filler Injections for Penile Augmentation in Men Reporting a Small Penis: A Multicenter, Patient-Blinded/Evaluator-Blinded, Non-Inferiority, Randomized Comparative Trial with 18 Months of Follow-up." J Clin Med. 2020;9(4):1024. doi:10.3390/jcm9041024

28. Campbell J, Gillis J. "A review of penile elongation surgery." Transl Androl Urol. 2017;6(1):69–78. doi:10.21037/tau.2016.11.19