This page has been consolidated. Manual modeling, the Wilson technique, the scratch technique, plication-over-IPP, plaque incision/grafting (PICS), Shaeer's punch technique, and length-restoration techniques are now covered together on the canonical IPP with Adjunctive Straightening page. The detailed historical and technique content below is preserved for direct-link readers.
Manual Modeling — the Wilson Technique
Manual modeling (MM) is an initial adjunctive maneuver for correcting residual penile curvature after inflatable penile prosthesis (IPP) placement in men with Peyronie's disease. In a retrospective multicenter IPP series of 499 men, 74.7% underwent modeling with or without the scratch technique and 82.4% received any adjunct.[1] Wilson and Delk described it in 1994,[2] and modeling with or without scratching was the most frequently used adjunct in that cohort.[1]
After the inflated cylinders provide internal hydraulic support, the penis is forcibly bent in the direction opposite the curvature to fracture the fibrotic plaque and allow the corpora to straighten along the cylinders.
Historical Background — the Wilson & Delk 1994 Series
The original technique was presented in a 138-patient series that established proof of concept:[2]
| Outcome | Value |
|---|---|
| Straight, rigid erection with modeling alone | 86% (118 pts) |
| Required relaxing plaque incisions (escalation) | 8% (11 pts) |
| Urethral perforation | 3% (4 pts) |
| Prosthesis infection | 3% (4 pts) |
| Mean follow-up | 32 months (9–84) |
| Prosthesis in active use at follow-up | 90% |
| Reported penile shortening | None |
| Reported glanular sensation impairment | None |
Wilson and Delk reported 4/138 (3%) urethral perforations during modeling; Lucas and colleagues later described sustained glanular pressure to reduce urethral injury during modeling.[2][4]
Step-by-Step Technique (Modern Standard)
Complete IPP insertion
Corporotomy, dilation, and bilateral cylinder placement per standard IPP protocol. Reservoir and pump placement completed. Corporotomies closed before modeling to prevent cylinder prolapse during the maneuver.
Maximal device inflation
Inflate the prosthesis to maximum rigidity. The inflated cylinders distribute force across the corporal surface, protecting the corpora from collapse and allowing the modeling force to concentrate on the fibrotic plaque rather than the underlying cavernous tissue.
Assess residual curvature
Use a goniometer with the device fully inflated to document the degree and direction of residual curvature. Thresholds vary by protocol: Katlowitz et al. performed adjunctive maneuvers above 20°; Lucas et al. modeled curvature above 30°; the EAU 2026 guideline describes no further action below 30° and modeling above 30° with limited evidence.[3][4][5][9]
Apply manual force
- Protect the pump before bending. Sharma and Smith describe placing a rubber-shod clamp on accessible tubing after full inflation and removing it before adding fluid for another modeling cycle; follow the device's tubing-handling precautions.[10]
- Grasp the penis firmly with both hands: one on the distal shaft at the level of the cylinder tips and one on the proximal shaft, with digital pressure over the corporotomy sites[8]
- Bend the erect penis forcibly in the direction opposite to the point of maximal curvature
- The goal is to fracture or disrupt the fibrotic plaque while the inflated cylinders prevent corporal collapse
- Force should be sustained, with a smooth, maximal bend rather than a jerk
Glanular pressure (critical safety maneuver)
Urethral perforation during modeling occurs when a distal cylinder tip is forced through the urethra at the fossa navicularis and emerges at the meatus.[8] It occurred in 4 of 138 patients (3%) in the original series.[2] Two measures protect against it:
- Glanular pressure. Pressure is maintained on the glans throughout each cycle to protect it over the cylinder tips; in the optimal-modeling series (40 patients bent for 90-second cycles with glanular pressure), no intraoperative or postoperative complication occurred at a mean follow-up of 29.9 months.[4]
- Bend from the distal shaft, not the glans. The hand performing the bend grips the distal shaft rather than levering on the glans, and downward pressure on the corporal tips is avoided, because that force drives a tip toward the fossa navicularis.[8]
Timed intervals
- Hold the bending force for 90-second intervals[4]
- Release, reassess with goniometer, and repeat as needed
- Lucas et al. repeated 90-second cycles as needed to reach <15° residual curvature.[4]
Final assessment
- Goniometer measurement in all planes
- Document final curvature
- If <15° residual → closure
- If 15–30° residual → EAU indicates no further intraoperative correction when curvature is <30°; Moncada described postoperative home modeling below 45° in an uncontrolled series.[9][6]
- If >30° residual → escalate to concurrent plication or grafting (PICS technique)
The Lucas "Optimal Modeling" Series
Lucas and colleagues described "optimal modeling" in a 2020 Urology retrospective review. Forty men with more than 30° of residual curvature after cylinder placement underwent modeling and were compared 1:1 with 40 matched men who needed no straightening:[4]
- Mean pre-modeling curvature: 47.8° (range 30–90°)
- Mean post-modeling curvature: 10.6° (range 0–30°, P<0.001)
- Mean curvature correction: 37°
- Mean operative time: 82.7 versus 75.8 minutes in the unmodeled group (P = .15)
- 87.5% of the 40 modeled men had <15° residual curvature.[4]
- No intraoperative or postoperative complication was reported in either the 40 modeled men or the 40 matched controls at a mean follow-up of 29.9 months.[4]
The Lucas protocol emphasized:
- 90-second intervals (versus older "until straight" approaches)
- Sustained glanular pressure throughout each cycle
- Goniometric documentation of pre- and post-modeling curvature
- Reassessment after each cycle and further 90-second modeling as needed toward <15° residual curvature.[4]
Extended Corporal Dilation (ECD)
Katlowitz and colleagues (Mulhall group) compared extended corporal dilation with serial Hegar dilators ≥14 mm before cylinder placement (n = 66) against standard dilation (n = 218) in a retrospective single-center 2026 J Sex Med study. Extended dilation was associated with less residual curvature and less need for adjunctive maneuvers:[5]
| Parameter | Standard dilation | Extended dilation |
|---|---|---|
| Technique | Dilamezinsert only | Dilamezinsert + serial Hegar ≥14 mm |
| Post-implant residual curvature | Higher | Significantly lower (P=.02) |
| Need for intraoperative adjunct | Higher | Significantly lower (P<.01) |
Proposed mechanism: ECD disrupts septal and tunical fibrosis during dilation, which gives the cylinders more room to straighten the corpus. One urethral perforation occurred during manual modeling in each group. The authors describe the data as preliminary and support eventual adoption of the technique.
Home Modeling — Postoperative Continuation
In Moncada's uncontrolled series, postoperative home modeling was used when residual curvature remained after intraoperative modeling.[6] The Moncada group's protocol is the best-described version.[6] In that series, men with less than 45° after intraoperative modeling did home modeling, and men with more than 45° had incision and grafting.
Moncada home-modeling protocol
| Parameter | Detail |
|---|---|
| Start | 4 weeks after IPP implantation |
| Device state | Prosthesis fully inflated |
| Maneuver | Manual bending opposite the residual curvature |
| Duration | Daily sessions |
| Total course | 6 months |
Outcomes (Moncada: 76 of 92 patients followed the home-modeling protocol):[6]
- Mean postoperative residual curvature after intraop MM: 29.7° ± 3.2° (range 5–50°)
- ≤10° residual at 3 months: 65/76 (85.5%) after home modeling.[6]
- ≤10° residual at 6 months: 72/76 (94.7%) after home modeling.[6]
- Satisfied or very satisfied with outcome at 6 months: 70/76 (92.1%) of the home-modeling group.[6]
In this uncontrolled series, most men with moderate residual curvature at closure reached ≤10° without an additional operative maneuver.
Why Inflatable Prostheses Are Required
The AUA guideline specifically notes: "modeling to maximize curvature correction is difficult to accomplish with semi-rigid devices."[7] Mechanism:
- Semi-rigid devices lack the hydraulic internal pressure that protects the corpora from collapse during bending
- Curvature modeling is difficult to accomplish with semi-rigid devices.[7]
- The EAU technique uses a maximally inflated prosthesis for modeling.[9]
Manual modeling is difficult with semi-rigid prostheses; the AUA prefers inflatable prostheses for PD prosthetic surgery .[7] When intraoperative modeling is anticipated, an inflatable prosthesis is generally preferred.[7]
Complications
| Complication | Rate | Prevention |
|---|---|---|
| Urethral perforation | Wilson–Delk: 4/138 (3%) during modeling; Lucas: 0/40 reported intraoperative or postoperative complications of any type[2][4] | Glanular pressure; bend from the distal shaft, not the glans |
| Prosthesis malfunction | Reported in 3.3–11.1% of intraoperative-modeling series; a modeling-attributable rate is uncertain[11] | Use a fully inflated device[9]; protect the pump and tubing during bending[10]; avoid sharp instruments near cylinders |
| Prosthesis infection | 4/138 (3%) in the original Wilson–Delk series; no complication reported in the Lucas modeling cohort (n = 40) | Standard IPP infection prevention[2][4] |
| Persistent curvature >30° | Rate not established in the cited modeling series | Reassess for plication or incision/grafting.[3] |
| Perceived shortening | Among the 124 of 138 Wilson–Delk patients still using prostheses at mean 32-month follow-up, none reported penile shortening[2] | Counsel that an IPP does not restore previously lost penile length[9] |
| Sensory change | No glanular sensory impairment was reported at mean 32-month follow-up in Wilson–Delk; the sensory-assessment denominator is unspecified[2] | Limit neurovascular-bundle mobilization during added tunical dissection because it can cause numbness[9] |
Urethral perforation
The classic complication and the one every surgeon must prepare for. Presentation is usually immediate, with blood at the urethral meatus, loss of Foley balloon integrity if present, or direct visualization of urethral injury at the end of the case. Management:
- Urethral injury without device exposure: Inspect and assess the site and extent before deciding whether to abort implantation or repair. For distal urethral injury, aborting implantation is described as the safest course; selected small injuries may heal without repair, and prolonged catheterization is not routinely needed.[10]
- Exposed cylinder through the urethra. Stop modeling, assess the injury, and remove the exposed cylinder. Sharma and Smith favor aborting implantation after distal urethral injury; selected cases may retain an uninjured contralateral cylinder, with urethral repair when indicated and replacement after healing.[10][12]
- Large urethral defect: Complete device explantation, urethral repair, suprapubic diversion, staged reimplantation
Cylinder damage
Sharma and Smith describe maximal inflation and a rubber-shod clamp on tubing to protect the pump during bending.[10]
Indication Criteria and Escalation Triggers
Ideal for modeling alone
- No validated ideal curvature range; EAU describes modeling for residual curvature >30° with limited evidence, while Katlowitz used >20° for any adjunct in one center.[9][5]
- Non-complex curvature (no hourglass, no hinge)
- No heavily calcified plaque
- Patient willing to comply with postoperative home modeling if indicated
Escalate to plication
- Residual curvature >30° after adequate modeling, when penile length and deformity favor plication.[4][9]
- Non-complex deformity
- Patient accepting some additional shortening
Escalate to grafting (PICS)
- Persistent residual curvature >30° after modeling when tunical incision creates a larger defect for which graft coverage may be used.[9]
- Complex deformity (hourglass, hinge)
- Calcified plaque that does not yield to modeling
- Severe pre-op curvature (>75°); sometimes indicates primary grafting
Summary of Adjunctive Ladder Comparison
| Technique | Reported curvature outcome | Op time added | Complexity | Key complication |
|---|---|---|---|---|
| Manual modeling with/without scratch[1] | Median curvature reduction 26° (IQR 20–39.5°) in selected patients | — | Low | Urethral perforation reported with modeling[2] |
| Optimal modeling (Lucas)[4] | Mean curvature reduction 37.2° (47.8° to 10.6°) | Incremental time not established; group means 82.7 vs 75.8 min (P=.15) | Low | No complication reported in either group (40 modeled men and 40 controls) at mean 29.9-month follow-up |
| Home modeling (postop)[6] | 72/76 (94.7%) had ≤10° residual at 6 mo; mean change not reported | N/A (postop) | Low | None reported |
| Concurrent plication[1] | Median curvature correction 40° (IQR 28.8–41.2°) in selected patients | — | Moderate | Palpable sutures, shortening |
| Concurrent grafting[1] | Median curvature correction 55° (IQR 48.8–73.8°) in selected grafting patients | — | High | Sensory change, hematoma |
Technical Pearls
- Use an inflatable prosthesis when modeling may be needed, consistent with the AUA Expert Opinion recommendation for prosthetic surgery in Peyronie’s disease.[7] This decision is made preoperatively.
- Inflate the device maximally before modeling; full hydraulic support is needed.
- Protect the glans and bend from the distal shaft: maintain glanular pressure throughout every cycle and avoid levering on the glans or pressing down on the cylinder tips.
- Use 90-second intervals with goniometer reassessment between cycles. Avoid "sudden snap" modeling.
- Document pre- and post-modeling curvature objectively with a goniometer. Subjective assessment is unreliable.
- Reassess before escalating. Repeat modeling with measurement between cycles as needed; if clinically important curvature persists, consider plication or incision with or without grafting.[3][4]
- Counsel patients preoperatively about the likelihood of home modeling. Compliance is needed.
-
- Extended corporal dilation: In a retrospective, single-center comparison of men with Peyronie's disease undergoing IPP placement, serial Hegar dilation ≥14 mm was associated with less post-implant residual curvature and less need for intraoperative adjunctive maneuvers (66 extended-dilation versus 218 standard-dilation cases).[5]
See Also
- Peyronie's disease — overview
- Prosthesis with adjunctive straightening
- Scratch technique & endocavernosal disruption
- Penile implants — implant models
References
1. Hammad MAM, Barham DW, Simhan J, et al. A multicenter evaluation of penile curvature correction in men with Peyronie's disease undergoing inflatable penile prosthesis placement. J Sex Med. 2025;22(2):349–355. doi:10.1093/jsxmed/qdae192
2. Wilson SK, Delk JR. A new treatment for Peyronie's disease: modeling the penis over an inflatable penile prosthesis. J Urol. 1994;152(4):1121–1123. doi:10.1016/s0022-5347(17)32519-3
3. Conlon WJ, Herzog BJ, Hellstrom WJG. Residual penile curvature correction by modeling during penile prosthesis implantation in Peyronie's disease patients. Int J Impot Res. 2023;35(7):639–642. doi:10.1038/s41443-023-00694-5
4. Lucas JW, Gross MS, Barlotta RM, et al. Optimal modeling: an updated method for safely and effectively eliminating curvature during penile prosthesis implantation. Urology. 2020;146:133–139. doi:10.1016/j.urology.2020.08.055
5. Katlowitz Y, Taniguchi H, Torremade J, Salter CA, Mulhall JP. Extended corporal dilation decreases the need for intraoperative adjuvant maneuvers for residual curvature after inflatable penile implant placement in men with Peyronie's disease. J Sex Med. 2026;23(5):qdag083. doi:10.1093/jsxmed/qdag083
6. Moncada I, Krishnappa P, Ascencios J, Lopez I, Martinez-Salamanca JI. Home modeling after penile prosthesis implantation in the management of residual curvature in Peyronie's disease. Int J Impot Res. 2021;33(6):616–619. doi:10.1038/s41443-020-0325-6
7. Nehra A, Alterowitz R, Culkin DJ, et al. Peyronie's disease: AUA guideline. J Urol. 2015;194(3):745–753. doi:10.1016/j.juro.2015.05.098
8. Haile E, Bajic P, Levine LA. Management of Residual Curvature in Men with Peyronie's Disease Following Penile Prosthesis Implantation. In: Miranda EP, Mulhall JP, eds. Penile Implant Surgery: Contemporary Challenges and Controversies. Springer; 2022:64-65.
9. European Association of Urology. "EAU Guidelines on Sexual and Reproductive Health: Penile Curvature." 2026. https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/penile-curvature
10. Sharma D, Smith RP. "Troubleshooting intraoperative complications of penile prosthesis placement." Transl Androl Urol. 2017;6(Suppl 5):S892-S897. doi:10.21037/tau.2017.07.13
11. Krishnappa P, Manfredi C, Sinha M, et al. "Penile Modeling in Peyronie's Disease: A Systematic Review of the Literature." Sex Med Rev. 2022;10(3):434–450. doi:10.1016/j.sxmr.2022.01.001
12. Ziegelmann MJ, Farrell MR, Levine LA. "Modern treatment strategies for penile prosthetics in Peyronie's disease: a contemporary clinical review." Asian J Androl. 2020;22(1):51–59. doi:10.4103/aja.aja_81_19