Surgical management of complex curvature in Peyronie’s disease

Purpose About 10% of Peyronie's patients are complex cases with severe curvature (>60 degrees), ventral plaque, multiplanar curvature, hour-glass/hinge deformity, notching deformity, and ossified plaque. In patients with complex Peyronie’s disease (PD), different techniques (shortening procedures, lengthening procedures, and penile prosthesis implantation (IPP)) may be necessary to achieve successful result. This review aims to analyze the various surgical techniques employed in the management of Peyronie's disease, with a specific focus on patients with complex deformity. Methods Articles focusing on the surgical management of complex curvature in Peyronie’s disease were searched in MEDLINE and PubMed published between 1990 and 2023. Results Shortening procedures are linked to penile shortening and are not recommended for complex cases such as notching, hour-glass deformity, or ossified plaque. Lengthening procedures are suitable for addressing complex curvatures without erectile dysfunction (ED) and are a more appropriate method for multiplanar curvatures. Penile prosthesis implantation (IPP), with or without additional procedures, is the gold standard for patients with ED and Peyronie's disease. IPP should also be the preferred option for cases of penile instability (hinge deformity) and has shown high satisfaction rates in all complex cases. Conclusion While surgical interventions for complex curvature in Peyronie's disease carry inherent risks, careful patient selection, meticulous surgical techniques, and post-operative care can help minimize complications and maximize positive outcome.


Introduction
Peyronie's disease (PD) is a urological condition characterized by the development of fibrous scar tissue within the penis, leading to penile curvature, pain, and erectile dysfunction (ED) [1].Surgical treatment is indicated in the stable phase of the disease [2].The main purpose of the surgical therapy for PD is to achieve functional and anatomical penis.The choice of the surgical method depends on the complexity of the curvature, erectile status and length of the penis.In the surgical treatment of Peyronie's disease, reconstructive surgeries (shortening and lengthening surgeries) are preferred in patients with good erectile capacity, while implantation of a penile prosthesis with or without deformity correction is preferred in patients with ED [3,4].About 10% of Peyronie's patients are complex cases with severe curvature (> 60 degrees), ventral plaque, multiplanar curvature, hour-glass/hinge deformity, notching deformity, and ossified plaque [5].
This review aims to analyze the various surgical techniques employed in the management of Peyronie's disease, with a specific focus on patients with complex deformity.

Methods
Articles focusing on the surgical management of complex curvature in Peyronie's disease were searched in MEDLINE and PubMed published between 1990 and 2023.The search terms used were "complex Peyronie's disease", "complex curvature", "notching", "hourglass", ''ventral curvature'', and "ossified plaque".All papers identified were Englishlanguage papers.

Notching-hourglass-hinge deformity
Notching is a deformity characterized by a collapse in one area of the penis (Fig. 1).The "hourglass" deformity is defined as a bilateral indentation at the same level on the penile shaft; in other words, it can be briefly defined as bilateral notching.There may also be a "hinge" effect that causes the penis to be unstable when erect.
Erectile dysfunction is usually associated with this type of deformity.Typically, there is noticeable softness in the part of the penis just before or after the indentation and insufficient hardness on erection.When the notch in the penis is substantial and circumferential, it often causes severe pivoting of the penis during penetration.
In a study evaluating 307 patients, the notching deformity and hourglass deformity rates were 2% and 2.6%, respectively [6].In another study, pure notching deformity was reported in 89 (12.6%) of 703 patients.Out of these cases, unilateral notching deformity was detected in 62.9% and hour-glass deformity was reported in 34.8% with both notching and hourglass deformities encountered in 2.7%.Most of the deformities were located in the distal or proximal parts of the penis [7].In another study in which patients over 65 years of age were evaluated, narrowing/notching deformity was reported in 62% of the patients [8].
In the patients with Peyronie's disease, during the followup process, erectile dysfunction is associated in 22-54% [9].Especially in those with notching/hourglass deformities, the rate of ED is reported to be higher in the literature.In a study ED was detected at a rate of 68.5% in patients with notching deformity, and this rate was statistically higher compared to patients with other curvature types [7].
Patients with notching/hourglass deformity and good erectile capacity can be effectively treated with plaque incision and grafting.In patients with poor erectile function, placement of an inflatable penile prosthesis is recommended with or without additional procedures [10].

Ventral curvature
The ventral penile curvature rate is lower compared to the other curvatures.A retrospective study involving 1001 patients revealed a ventral curvature rate of 15%.The occurrence of ventral curvature can reach up to 20%, particularly among patients with a curvature exceeding 60 degrees [11].In a recent study, men aged over 65 years showed a 10% incidence of ventral curvature [8].In a study evaluating patients with ventral curvature, 57% were treated with Nesbit/plication procedures [4].In experienced medical centers, plaque incision and grafting surgery can also be performed, involving the mobilization of the urethra and neurovascular bundle [12].In patients with ventral curvature, for mobilizing the neurovascular bundle, lateral dissection of the neurovascular bundle may be preferred [13].

Severe curvature (> 60°)
Patients with penile curvature exceeding 60° in one or biplanar direction are also considered as having complex deformity.In those with good erectile capacity, tunical lengthening surgeries are performed, while in those with ED, treatment involves penile prosthesis implantation with additional shortening and lengthening procedures [2,13,14] (Fig. 2).In a study, the effectiveness of penile plication was compared in patients with severe curvature and patients with mild to moderate curvature.The success rate was found to be similar in those with severe to mild/moderate curvature (74.5% vs. 74.5%).The conclusion of the study is that shortening procedures could be preferred in selected cases, even in patients with severe deformity [15].In patients with severe deformity, ventral curvature is encountered more and lateral curvature is less frequent, whereas the incidence of ventral curvature is higher compared to all type of deformities [11].The presence of ED is an predictive parameter in the selection of type of surgical.A study evaluating the relationship between the degree of curvature and ED rate found no relationship based on the degree of curvature (70.7% and 68.4%) [9].

Ossified plaque
One of the complex and rare presentation of Peyronie's disease is characterized by ossified plaque (Fig. 3).To date, it has been reported rarely in the literature, often in the form of case presentations [16].As Peyronie's disease progresses, approximately 15-25% of plaques can become calcified or ossified [17].Calcified plaques, typically palpable, lead to sexual dysfunction causing penile curvature and pain.At this stage, the main treatment strategy involves the removal of the ossified plaque with or without grafting.In patients with erectile dysfunction (ED), preference should be given to penile prosthesis implantation after the removal or incision of the calcified plaque with or without grafting [18,19].

Management of patients with complex curvature in Peyronie's disease
In order to assess the type and severe of the deformity, the penis should be examined in a flaccid and erect state.Particularly, examining the penis while erect is an essential step for evaluating complex curvatures [2].Objective assessment of the curvature can be performed by inducing an erection through intracavernosal injection of a vasoactive agent.The assessment of deformity by ultrasound, computed tomography, or magnetic resonance imaging is not reccomended [2].However, ultrasound has a role in distinguishing calcified plaques.Similarly, the AUA guideline recommend before invasive treatment curvature assessment with intracavernosal injection (ICI) [20].The ICI test is considered as the gold standard for evaluating complex deformities such as notching and hourglass type, in addition to providing an objective assessment of penis length and curvature degree [21].
Shortening procedures involve reducing the convex side of the penis from the area where it is most pronounced, aiming to straighten the penis.Various shortening procedures, including Nesbit, have been described.The success rate and satisfaction rate of these shortening procedures are similar [22].Correction rate for curvature range between 42 and 100%, with overall satisfaction varying from 68 to 100% [22].The shortening procedures are associated with shortening of penis up to 2.5 cm [23].Approximately 1 cm of penile shortening is expected for every 20 degrees of correction after penile plication surgery [24] (Table 1).
Shortening, especially when combined with hourglass or hinge deformities, can further exacerbate hinge deformities.Therefore, shortening procedures are generally not preferred for complex cases such as notching and hourglass deformities (Table 1).However, they can be used as a treatment option for patients with advanced curvature (> 60°), adequate erectile function, and penile length.Limited studies are available on the effectiveness of the plication technique in advanced curvature.In a study, 18 patients with curvature > 60° and 14 patients with biplanar curvature underwent Nesbit/plication surgery, and similar success rates were found when compared to lengthening procedures [6].Similarly, in another study by Adibi and colleagues, plication was performed on 43 patients with severe deformity (11 biplanar, 32 severe curvature), concluding that plication is effective and safe [25].In another recent study, penile plication was shown to be effective and safe in patients with severe curvature (> 60°) [26].The effectiveness and safety of Nesbit/plication surgeries have also been demonstrated for ventral curvature [27].In conclusion, for complex Peyronie's patients excluding hourglass, notching, and hinge deformities, shortening surgeries can be preferred either alone or in conjunction with other surgical options.
Lengthening procedures are particularly preferred in patients with complex curvatures such as hourglass, notching, and multiplanar curvature without erectile dysfunction.Plaque excision is no longer favored due to high postoperative erectile dysfunction rate and large defect caused after excision.It appears more suitable to release the scar tissue after creating sufficient exposure for graft placement through plaque incision [2].Smaller defect areas and potentially lower postoperative erectile dysfunction rates can be achieved with plaque incision only.However, the disadvantage is that additional plication sutures may be necessary to correct the curvature after grafting [28].In a study, residual curvature was observed in 5.2% of cases after lengthening surgeries, and salvage plication procedures were performed to correct the residual curvature [29].
In a recent study, aiming to reduce postoperative erectile dysfunction rate, multiple transverse incisions only were performed in one group and incision and grafting with collagen fleece was used in the second group [30].Both methods are reported as effective and reliable with low erectile dysfunction rate.However, in patients with calcified plaques, removal of the calcification would be a suitable option.In some cases, osteotomes or similar bone-cutting instruments might be necessary for ossified plaque incision/removal.In appropriate patients, tunica-sparing bone excision has been described.In a study involving 12 patients with dorsal penile curvature between 10 and 90°, tunica albuginea was freed and the calcified plaque was removed [19].At a seven-month follow-up, successful erections were detected in 80% of patients.
With the advancement of plaque incision and grafting techniques, various types of incisions have been described.Historically, I incision, H-type incision and finally bilateral Y-shaped incision (Egydio) type have been reported as options for lengthening surgeries [31].A study by Lue and El-Sakka in 1998, involves dissecting the neurovascular bundle (NVB) from the dorsal surface of the tunica albuginea (medial dissection).An H-shaped incision is made in the tunica to encompass the center of the plaque, and the graft size is determined.Subsequently, the saphenous or deep dorsal vein is used as a graft.In the reported series, 17% of the 112 patients followed experienced penile shortening.In patients with hourglass-notching deformity, longitudinal incision should be preferred instead of transverse incision [32,33].
According to the technique described by Egydio in 2002, a rectangular tunical defect is created by making a transverse double Y incision, with a 120-degree angle at each end, branching at the maximum curvature point [34].This incision allows for better expansion of the depressed area and correction of the deformity [34].The Egydio technique has been reported to have higher rate of erectile dysfunction based only one study.While debates continue about which incision type is superior, a study has suggested that a modified double Y incision is likely associated with fewer complications and better geometry [35].
In the incision and grafting technique, it is preferable to use graft materials that are easy to manipulate and suture, flexible enough to allow sufficient stretch for erection, sufficiently rigid to prevent aneurysm formation, readily available, cost-effective, and associated with low morbidity rates.The available graft materials can be classified as autografts, allografts, xenografts, and synthetic grafts.In previous studies, no superiority has been demonstrated among these graft types, and no particular graft type advantageous over others has been identified [21].In complex cases, the choice of graft material also depends on the surgeon's experience, the patient's preference, and the availability of the material.The success rates of grafts vary between 56 and 100%.An average of 20-25% penile shortening and 15-20% de novo ED are reported [2] (Table 1).
Commonly used grafts are saphenous vein graft, human pericardium, small intestinal submucosa (SIS) and bovine pericardium.The success rate with the sapehnous vein graft has been reported to be avarage 85.6%.The disadvantage of using the saphenous vein graft is additional surgical intervention.The success rate in patients with human pericardium, SIS and bovine pericardium is 93.1%, 83% and 87.4%, respectively [2,36].
In the extratunical graft technique described by Lue, it has been reported that a graft is used without comprimising the integrity of tunica albuginea [37].After achieving an erection, in patients with curvature in addition to hourglass/ notching deformity, a plication procedure is performed.Subsequently, over the notched area, the defect is filled with cadaveric pericardium graft material according to the size of the defect.In the presence of an hourglass deformity, the graft is wrapped around the notching area on both sides and secured to the corpus cavernosum adjacent to the corpus spongiosum.This method has been defined for preventing de novo erectile dysfunction (ED) development.Among 18 patients followed for over six months, no development of ED was observed.Similar results were obtained in another study using bovine pericardium as the graft material [38].The limitation of these studies lies in their relatively short follow-up periods.In a recent correspondens by Levine, the extratunical grafting method with porcine dermal graft was used in 35 patients with successful outcome [39].
Penile prosthesis implantation is the gold standard for patients with erectile dysfunction requiring surgery due to Peyronie's disease.It is also suitable for patients with failed shortening and lengthening surgeries, as well as those with complex deformities involving penile instability because of hinge effect.
Penile curvature can be corrected between 33 and 90% solely through penile prosthesis implantation without need of additional procedures.Auxiliary procedures after IPP due to residual curvature is required in 20-30% of the patients.It was demonstrated that preoperative curvatures ≤ 30° frequently did not necessitate additional procedures, whereas intervention rates increased to 12% for curvatures of 31°-45°, 75% for 45°-60° curvatures, and up to 100% for curvatures exceeding 60° [40].Especially in cases of complex deformities, a significant portion of the curvatures may not be corrected solely through penile prosthesis implantation.In complex cases, in patients with both Peyronie's disease and erectile dysfunction, satisfaction rates with penile prosthesis implantation are above 90% [35].
In patients with residual curvature after penile prosthesis implantation, correction should be performed through shortening gprocedures (penile plication/Nesbit procedures) or lenghtening procedures (plaque incision with or without grafting).In a study evaluating 18 patients who underwent penile plication to correct curvature before prosthesis placement, complete straightening of the curvature with 73% reduction of the penile length was reported [41].Almost all patients have straight penis with shortening procedures after IPP.
Several types of complex deformities require plaque incision with or without grafting.In cases of hinge/notching deformity, additional corrective procedures can be performed through lateral longitudinal penile incisions of the tunica over the prosthesis [2].In a study evaluating patients who underwent plaque incision without grafting, a complete improvement in the penis was observed in 95% of cases during an average follow-up of 35 months [42].In similar studies, an average increase in penile length of 3 cm and success rate of %90-100 was reported with tunical incision without grafting [43,44].If the tunical opening after plaque incision is greater than 2 cm, the use of a graft is recommended to prevent device aneurysm formation [28].The success rate of autologous graft materials (saphenous vein, rectus fascia) after plaque incision ranges from 94 to 100%.Similarly, the success rate of pericardial graft is reported to be between 82 and 100% [2].Recently, the use of collagen fleece which shortens operation time and reduces the likelihood of damaging cylinders success rate 92.6% was reported [2].The use of collagen fleece to correct residual curvature during inflatable penile prosthesis implantation (PICS technique) in patients with complex Peyronie disease was reported by Falcone et al.In this study, 31 of 36 patients (84%) achieved a totally straight penis.Only 6 patients (16%) experienced a residual penile curvature (< 20° in all cases) after the procedure [45].In an other study, Farrell and colleagues compared hemostatic grafts and pericardial allograft in patients with tunical openings greater than 2 cm after inflatable penile prosthesis placement [46].Evaluation of 18 patients using hemostatic grafts showed similar outcome compared to pericardial allograft with shortened operation time.In a recently published study, in patients with an average penile curvature of 72 degrees, the groups with and without graft usage were compared.In conclusion, no differences in patient satisfaction and complications were reported between the two groups [30].
Placement of penil prosthesis can be performed through penoscrotal, infrapubic or subcoronal incision.In patients with dorsal and lateral curvature, beginning the surgery

ED (+) ED (-)
Fig. 4 Surgical algorithm of complex curvature in Peyronie's disease with a transverse penoscrotal or ventral longitudinal penile incision is appropriate.Similarly, for those with ventral curvature who are planned for additional corrective surgery following prosthesis implantation, circumcision incision may be preferred.Subcoronal incision for penile prosthesis implantation is an effective method as it does not require an additional incision for curvature correction.In a study, IPP implantation with a subcoronal incision was performed to 66 patients [47].The authors concluded that subcoronal incision is an effective and reliable method with low complication and revision rates.
Especially in patients with a shortened penis, penile prosthesis implantation along with various incision techniques and grafting methods appears to be suitable for preserving or increasing penis length [10].In 2015, Egydio and colleagues described a method known as MoST (Modified Sliding Technique).The key point of this approach is to create numerous tunical defects, each of which is small enough to not require closure with grafts, in order to achieve penile length.Another modification to the sliding technique was introduced by Egydio in 2018 (Multiple Slit Technique-MUST).The principle of this approach involves using multiple transverse and longitudinal incisions to expand contracted sections of the tunica albuginea; thereby, achieving penile length, without the need for grafts since the defects are < 2 cm in length [14,43].These methods, which report an increase in penile length up to 3-3.5 cm, may be associated with complications such as compromised blood supply due to stretching of the neurovascular bundle, glans necrosis, hypoesthesia, and urethral injury.Therefore, these procedures are more appropriate when performed by experienced centers.

Conclusion
Complex curvature in Peyronie's disease presents a challenging and often distressing condition for affected patients.Treatment options for complex curvature in Peyronie's disease vary depending on the individual case.Surgical intervention, including shortening techniques (penile plication, Nesbit), lengthening procedures (plaque incision with or without grafting) or penile prosthesis implantation with or without grafting, may be necessary to achieve satisfactory outcome (Fig. 4).
In conclusion, shortening procedures are linked to penile shortening (up to 2.5 cm) and are not recommended for complex cases such as notching, hourglass deformity, or ossified plaque.Lengthening procedures are suitable for addressing complex curvatures without erectile dysfunction (ED) and are a more appropriate method for multiplanar curvatures.Penile Prosthesis Implantation (IPP), with or without additional procedures, is the gold standard for patients with ED and Peyronie's Disease.IPP should also be the preferred option for cases of penile instability (hinge deformity) and has shown high satisfaction rates in all complex cases.While surgical interventions for complex curvature in Peyronie's disease carry inherent risks, careful patient selection, meticulous surgical techniques, and postoperative care in experienced centers can help minimize complications and maximize positive outcome.