Perioperative therapies and techniques to enhance penile dimensional and functional outcomes following inflatable penile prosthesis implantation: a contemporary 10-year systematic review

Abstract

Implantation of inflatable penile prosthesis should be considered as a definitive treatment of erectile dysfunction. However, the sole procedure might not allow for optimal dimensional and functional outcomes. The aim of this study was to systematically review the literature and present the findings on the optimal choice of perioperative methods, surgical techniques, and pharmacotherapy to improve penile length, curvature, and erectile function. Fifteen studies and 697 men were included. Nine studies focused on intraoperative techniques only, while 6 described intra- and postoperative methods. Regarding the outcomes, curvature of the penis was reported in 12 studies, penile length in 5 studies, penile girth in 2 studies, and the International Index of Erectile Function-5 (IIEF-5) score in 7 studies. According to this systematic review, extreme angulation can be reduced using plaque/corporal incisions and grafting with collagen fleece, as well as “scratch” technique with postoperative vacuum therapy. Also, among patients with preoperative curvature of approximately 30°–40°, penile plication, corporoplasty, tunica expansion procedure, manual, and at-home modeling can provide good results. In addition, corporal incisions plus grafting, as well as postoperative vacuum therapy might be the most beneficial in terms of length improvement. Importantly, penile implant in combination with the sealing, daily, and early prosthesis activation proved to improve length. Moreover, postoperative vacuum therapy has also been shown to greatly increase penile circumference. Finally, penile implant in combination with the sealing, corporal incisions plus grafting, “scratch” technique, vacuum therapy, and phosphodiesterase-5 inhibitor are all associated with major improvements in sexual function.

INTRODUCTION

Erectile dysfunction (ED) is a common disease, which afflicts 19.2%–52% of men.1 Additionally, its prevalence rises from 2.3% of 30 years old to 53.4% of 80 years old.1 Even though a variety of factors can contribute to ED development, it can be classified as primarily psychogenic, organic (e.g., vasculogenic, neurogenic, and drug-induced), or mixed.2 Crucially, in the majority of males suffering from ED, multiple pathophysiological pathways coexist.1 Also, ED and male infertility is associated with various chronic diseases and increased mortality.3,4,5,6,7

One of the organic conditions causing ED is Peyronie’s disease (PD). PD is an acquired structural abnormality of the penis, caused by the fibrosis of the tunica albuginea. It usually develops in predisposed patients as a result of penile trauma, followed by dysregulated healing process.8

Treatment of ED includes lifestyle changes, cognitive behavior therapy, pharmacotherapy (phosphodiesterase type 5 inhibitors, and topical alprostadil), intracavernous injections, vacuum therapy, shockwave therapy, and penile prosthesis implantation. Moreover, patients with PD might benefit from intralesional collagenase injections, penile traction therapy, surgical correction, and other topical/oral drugs.8

Nevertheless, in patients who are not optimal candidates for pharmacotherapy, prefer definite treatment, or do not respond to other modalities, implantation of a penile prosthesis should be considered.1

Currently, there is no consensus regarding optimal surgical techniques that enhance penile prosthesis implantation.9,10,11 Moreover, multiple perioperative therapies have been proposed in order to improve the results of the surgery. That is why we aimed to systematically review the literature and present the findings on the optimal choice of perioperative methods, surgical techniques, and pharmacotherapy to improve penile length, curvature, and functional outcomes.

MATERIALS AND METHODS

Evidence acquisition

We performed a systematic literature search of PubMed, Embase, and Cochrane databases on June 5, 2024, without language restrictions. The search was limited to the articles published in 2014 and later. Search terms included, but were not limited to: “inflatable” AND “penile” AND “prosthesis” AND (“satisfaction” OR “dimension” OR “length” OR “curvature” OR “girth”). Only original articles were included and assessed. Case reports, abstracts and meeting reports were excluded from the analysis. The reference lists of the studies selected for full-text review were also screened for relevant articles.

Selection of the studies and criteria of inclusion

Entry into the analysis was restricted to data collected from original studies that examined males who underwent inflatable penile prosthesis (IPP) implantation. The review was prepared in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA).12 Five authors (JŁ, ŁN, DC, VA, and CMS) independently screened the titles and abstracts of all articles using the predefined inclusion criteria. Full-text articles were assessed by five authors (JŁ, EDB, WK, ASH, and FDG) to determine whether they met the inclusion criteria. Final inclusion of the studies were approved by all of the investigators. Finally, a critical analysis and data synthesis of the selected articles has been performed.

In order to include and compare homogeneous data, we predefined the outcomes and analyzed the articles that reported their results accordingly. The length was defined as a measurement of a stretched flaccid penis from the pubic bone to meatus, girth as a circumference at the base of the penis, and curvature as a maximal deviation of the erect penis from the axis in degrees. Sexual function was assessed using the International Index of Erectile Function-5 (IIEF-5) questionnaire.

Assessment of quality for studies included

Two reviewers (JŁ and FDG) independently assessed the quality of the included studies using the “Quality Assessment Tool for Before-After (Pre-Post) Studies With No Control Group” provided by the National Institute of Health.13 The potential risk of bias, measurement bias, and others are presented in Supplementary Table 1. Studies were rated as good, fair, and poor quality, where high risk of bias translated to a rating of poor quality (“−”) and low risk of bias translated to a rating of good quality (“+”).

Supplementary Table 1.

Quality assessment tool for before–after (pre–post) studies with no control group

Study	1	2	3	4	5	6	7	8	9	10	11	12
Antonini et al.14 2020	+	+	−	+	+	+	+	−	NR	+	−	NA
Antonini et al.15 2018	+	+	+	+	+	+	−	−	+	+	−	NA
Caraceni et al.16 2014	+	−	NR	NR	−	+	+	−	NR	+	−	NA
Chung et al.17 2014	+	+	+	+	−	+	+	−	+	−	−	NA
Falcone et al.18 2023	+	+	+	+	−	+	+	−	+	−	−	NA
Fernández-Pascual et al.19 2019	+	+	+	+	−	+	+	−	+	−	−	NA
Hatzichristodoulou et al.20 2020	+	−	NR	NR	+	+	+	−	+	−	−	NA
Hatzichristodoulou21 2018	+	−	NR	NR	−	+	−	−	+	−	−	NA
Henry et al.22 2015	+	+	−	+	−	+	+	−	+	+	−	NA
Lucas et al.23 2020	+	+	+	+	−	+	+	−	+	−	−	NA
Moncada et al.24 2021	+	−	NR	NR	+	+	+	−	+	−	−	NA
Pyrgidis et al.25 2023	+	+	+	+	−	+	+	−	+	+	−	NA
Razdan et al.26 2024	+	−	NR	NR	−	+	+	−	+	−	−	NA
Tausch et al.27 2015	+	−	NR	NR	−	+	+	−	+	−	−	NA
Wang et al.28 2021	+	+	+	+	+	+	+	−	+	+	−	NA

1: was the study question or objective clearly stated? 2: were eligibility/selection criteria for the study population prespecified and clearly described? 3: were the participants in the study representative of those who would be eligible for the test/service/intervention in the general or clinical population of interest? 4: were all eligible participants that met the prespecified entry criteria enrolled? 5: was the sample size sufficiently large to provide confidence in the findings? 6: was the test/service/intervention clearly described and delivered consistently across the study population? 7: were the outcome measures prespecified, clearly defined, valid, reliable, and assessed consistently across all study participants? 8: were the people assessing the outcomes blinded to the participant’s exposures/interventions? 9: was the loss to follow-up after baseline 20% or less? Were those lost to follow-up accounted for in the analysis? 10: did the statistical methods examine changes in outcome measures from before to after the intervention? Were statistical tests done that provided P values for the pre-to-post changes? 11: were outcome measures of interest taken multiple times before the intervention and multiple times after the intervention (i.e., did they use an interrupted time-series design)? 12: if the intervention was conducted at a group level (e.g., a whole hospital, a community, etc.) did the statistical analysis take into account the use of individual-level data to determine effects at the group level? NR: not reported; NA: not applicable; +: yes; −: no

RESULTS

Search results

The initial search yielded 433 records (PubMed: 184; Embase: 223; and Cochrane Library: 26). One hundred and thirty-seven articles were duplicates and were removed. Next, 296 articles were screened by title and abstract analysis to identify potentially relevant articles. 256 records were excluded and the remaining 40 were sought for retrieval. 36 full-text reports were assessed for eligibility. After an in-depth analysis, 21 more articles did not meet the inclusion criteria. Finally, 15 studies were included in this review (Figure 1).

Figure 1.

Preferred Reporting Items for Systematic Reviews and Meta-analyses flowchart of the study selection process.

No study was considered fatally flawed as per the “Quality Assessment Tool for Before-After (Pre-Post) Studies With No Control Group”.13 However, none of the studies implemented multiple measurements before the intervention. Also, people who evaluated the outcomes were not blinded to the participants’ interventions. Moreover, study groups were often small, and few papers performed statistical significance analyses on the pre- and post-intervention outcomes. Finally, some articles did not provide sufficient data on the inclusion/exclusion criteria (Supplementary Table 1).14,15,16,17,18,19,20,21,22,23,24,25,26,27,28

Study locations and types

Nine of the included studies focused solely on intraoperative techniques (Table 1).17,18,19,20,21,23,25,26,27 Two retrospective studies from the USA described penile plication.17,27 Tausch et al.27 also performed corporoplasty over IPP. Plaque incision and grafting with collagen fleece was assessed by four studies (2 retrospective, 1 prospective, and 1 not specified) based in Europe (Italy and Germany) and the USA.18,20,21,25 Additionally, a very similar technique, multiple corporal incisions and grafting with collagen fleece, was implemented in 1 retrospective research from Spain.19 One retrospective paper evaluated the tunica expansion procedure (TEP).26 Finally, 1 retrospective research from the USA described a modified manual modeling technique called “optimal modeling”.23

Table 1.

Baseline characteristics of the included studies

Study	Technique	Country	Study design	Study duration	Patients (n)	Men with PD, n (%)	Patient’s age (year)	Follow-up (month)	Surgical approach of IPP implantation	Reported outcomes of interest
Antonini et al.14 2020	Postoperative vacuum therapy	Italy and the USA	Prospective, multicenter	2014–2017	74	NR	Median: 56	Median: 12	Infrapubic	Length, girth, and IIEF-5
Antonini et al.15 2018	“Scratch” technique and postoperative vacuum therapy	Italy and the USA	Prospective, multicenter	2013–2016	145	145 (100.0)	Mean: 51.6	Median: 12	Infrapubic	Curvature and IIEF-5
Caraceni et al.16 2014	Early prosthesis activation	Egypt	Retrospective, single-center	2010–2012	19	0 (0)	Mean: 68.9	Mean: 6.3	NR	Length
Chung et al.17 2014	Penile plication	The USA	Retrospective, single-center	2010–2013	18	18 (100.0)	Mean: 63	NR	Penoscrotal	Curvature
Falcone et al.18 2023	PICS	Italy and Germany	Retrospective, multicenter	2018–2021	37	37 (100.0)	Median: 62	Median: 14	Penoscrotal	Curvature and IIEF-5
Fernández-Pascual et al.19 2019	Multiple corporal incisions and grafting with collagen fleece	Spain	Retrospective, single-center	2015–2018	27	27 (100.0)	Mean: 52.6	NR	Penoscrotal	Curvature, length, and IIEF-5
Hatzichristodoulou et al.20 2020	PICS	Germany and the USA	Retrospective, multicenter	2015–2019	51	51 (100.0)	Mean: 59.9	Mean: 10.6	Penoscrotal	Curvature
Hatzichristodoulou21 2018	PICS	Germany	Single-center	2015–2017	15	15 (100.0)	Mean: 61.7	Mean: 15.1	Penoscrotal	Curvature and IIEF-5
Henry et al.22 2015	Daily prosthesis inflation	The USA	Prospective, multicenter	2007–2009	31	0 (0)	Mean: 66.2	Mean: 12	Penoscrotal or infrapubic	Length and girth
Lucas et al.23 2020	Manual modeling	The USA	Retrospective, multicenter	2015–2019	40	NR	Mean: 60.4	Mean: 24.9	Penoscrotal or infrapubic	Curvature
Moncada et al.24 2021	Manual modeling Group 1: incision grafting Group 2: home modeling	Spain and India	Retrospective, multicenter	2008–2017	Group 1: 16 Group 2: 76	92 (100.0)	Mean: 62.8	NR	Penoscrotal	Curvature
Pyrgidis et al.25 2023	PICS	Germany	Prospective, single-center	2018–2020	25	25 (100.0)	Mean: 61.8	Mean: 24	Penoscrotal	Curvature, length, and IIEF-5
Razdan et al.26 2024	TEP	The USA	Retrospective, single-center	2017–2021	32	32 (100.0)	Mean: 64	NR	NR	Curvature
Tausch et al.27 2015	Group 1: penile plication Group 2: corporoplasty over IPP	The USA	Retrospective, single-center	2007–2014	Group 1: 23 Group 2: 7	NR	NR	Mean: 13	Penoscrotal	Curvature
Wang et al.28 2021	PDE5i	China	Prospective, single-center	2011–2015	61	6 (9.8)	Mean: 57.7	Mean: 60	Penoscrotal	IIEF-5

NR: not reported; PICS: penile implant in combination with the sealing; IPP: inflatable penile prosthesis; IIEF-5: International Index of Erectile Function-5; PD: Peyronie’s disease; TEP: tunica expansion procedure; PDE5i: phosphodiesterase-5 inhibitor

The remaining 6 studies either described the combinations of intra- and postoperative techniques or postoperative methods only (Table 1).14,15,16,22,24,28 One retrospective study from Spain and India examined the effect of manual and home modeling.24 Two prospective studies regarding the use of vacuum therapy after surgery were conducted in Italy and the USA, respectively.14,15 The outcomes of aggressive cylinder sizing and penile rehabilitation, by daily prosthesis inflation for a year, were studied in prospective research from the USA.22 Very early prosthesis activation was evaluated by a single retrospective study from Egypt.16 Also, Wang et al.28 explored the satisfactory outcomes of postoperative phosphodiesterase-5 inhibitor (PDE5i) use in a prospective study from China.

Study sample sizes, clinical characteristics, follow-up, and reported outcomes

In total, 697 males with ED were included from 15 studies.14,15,16,17,18,19,20,21,22,23,24,25,26,27,28 The study groups varied from 7 patients to 145 patients. In addition, the included articles were extremely heterogeneous in terms of proportions of PD patients. Nine studies only included men with PD, and 2 studies excluded patients with PD, while 3 did not report these data. Nonetheless, 448 (64.3%) men in this review were diagnosed with PD.

Mean age of the patients in the included studies varied from 51.6 to 68.9 years. In terms of follow-up, the included articles reported mean, median and fixed observation times, or did not report it. Median follow-up time in 3 studies was 12–14 months, mean follow-up time in 5 studies was 6.3–24.9 months, and 3 studies set the follow-up time to 12 months, 60 months, and 24 months, respectively.

The majority of the studies (11 studies) used a penoscrotal approach in IPP implantation, while infrapubic incision was performed in 4 studies. Also, two papers did not specify the surgical technique of IPP implantation.

Regarding the outcomes, curvature of the penis was reported in 12 studies, penile length in 5 studies, penile girth in 2 studies, and IIEF-5 score in 7 studies (Table 2).

Table 2.

Outcomes of interest reported in the included studies

Variable	Technique	Study	Preoperation	Latest postoperation	Change
Curvature	Penile plication	Chung et al.17 2014	Mean: 39°	All<5°	8° per suture
		Tausch et al.27 2015	Mean: 38°	All<10°	NR
	PICS	Falcone et al.18 2023	Median: 75°	84%: 0 16%: <20°	NR
		Hatzichristodoulou et al.20 2020	Mean: 69.6°	88%: 0 12%: <15°	NR
		Hatzichristodoulou21 2018	Mean: 66.7° (after IPP placement)	80%: 0 20%: <10°	NR
		Pyrgidis et al.25 2023	Mean: 64.8°	84%: 0 16%: <15°	NR
	Corporal incisions and grafting with collagen fleece	Fernández-Pascual et al.19 2019	Mean: 70.2°	Mean: 9.7°	Mean: 60.5°
	Corporoplasty over IPP	Tausch et al.27 2015	Mean: 33°	All <10°	NR
	TEP	Razdan et al.26 2024	Mean: 20°	Mean: 5°	Mean: 15°
	Manual modeling	Lucas et al.23 2020	Mean: 47.8°	Mean: 10.6°	Mean: 37.2°
	Manual modeling Group 1: incision grafting Group 2: home modeling	Moncada et al.24 2021	Mean: 39.4°	Mean: 29.7° after MM Group 1: NR Group 2: 94.7% <10°	Mean: 9.7° after MM
	“Scratch” technique and postoperative vacuum therapy	Antonini et al.15 2018	Mean: 65.8°	Mean: 10°	Mean: 55.8°
Length (cm)	PICS	Pyrgidis et al.25 2023	Mean: 15.0	Mean: 16.4	Mean: increased by 1.4
	Corporal incisions and grafting with collagen fleece	Fernández-Pascual et al.19 2019	Mean: 12.1	Mean: 14.8	Mean: increased by 2.7
	Postoperative vacuum therapy	Antonini et al.14 2020	Median: 14 Mean: 13.9	Median: 17 Mean: 16.7	Median: increased by 3 Mean: increased by 2.8
	Daily prosthesis inflation	Henry et al.22 2015	NR	NR	Mean: increased by 1.0 from postoperative
	Early prosthesis activation	Caraceni et al.16 2014	Mean: 14.6	Mean: 15.0	Increased by 0.4
Girth (cm)	Postoperative vacuum therapy	Antonini et al.14 2020	Median: 9 Mean: 9.3	Median: 11 Mean: 11.3	Median: increased by 2 Mean: increased by 2
	Daily prosthesis inflation	Henry et al.22 2015	NR	NR	Mean: increased by 1.1 from postoperative
IIEF-5 score	PICS	Falcone et al.18 2023	Median: 10	Median: 23.5	Increased by 13.5
		Hatzichristodoulou21 2018	NR	Mean: 24.2	NR
		Pyrgidis et al.25 2023	Mean: 10.0	Mean: 23.7	Increased by 13.7
	Corporal incisions and grafting with collagen fleece	Fernández-Pascual et al.19 2019	Mean: 11.1	NR	NR
	“Scratch” technique and postoperative vacuum therapy	Antonini et al.15 2018	Mean: 9.8	Mean: 24.1	Increased by 14.3
	Postoperative vacuum therapy	Antonini et al.14 2020	Median: 9	Median: 25	Increased by 16
	PDE5i	Wang et al.28 2021	All<10	All>20	All increased by at least 10

NR: not reported; PICS: penile implant in combination with the sealing; IPP: inflatable penile prosthesis; MM: manual modeling; IIEF-5: International Index of Erectile Function-5; TEP: tunica expansion procedure; PDE5i: phosphodiesterase-5 inhibitor

Intraoperative techniques

Penile plication can be implemented in order to reduce the curvature of the penis. In the included studies, it was performed using the following steps: (1) artificial erection in order to visualize penile curvature, (2) scrotal incision, (3) distal retraction of the incision to expose the tunica albuginea, (4) placement of parallel inverting interrupted sutures in the tunica albuginea at the convex opposite of the largest curvature, (5) repeat artificial erection to confirm the correction, and (6) IPP placement through corporotomies proximal to the plication sutures.17,27

A retrospective study on a group of 18 patients with PD found that penile plication reduced the penile curvature at a rate of 8° per suture. The authors were able to reduce penile angle from a mean 39° to under 5° in all participants, using a median of 4 sutures.17

Very similar research by Tausch et al.27 explored the effect of penile plication in a group of 23 men. In this study, the mean preoperative curve was 38°, a median of 4 sutures were used and each suture provided a correction of 8° as well. Finally, all of the males that underwent penile plication had a residual curve of under 10°.27

The penile implant in combination with the sealing (PICS) has been performed in 128 males in four studies included in this review. It is primarily used in order to reduce the remaining curvature of the penis immediately after IPP implantation. The procedure consists of: (1) IPP implantation, inflation, curvature check, and deflation; (2) subcoronal circumferential incision, degloving of the penile shaft, incision of the Buck fascia, and neurovascular bundle mobilization; (3) transversal plaque incision with electrocautery at the point of maximal curvature; and (4) sealing the defect of the tunica albuginea with a fibrin-coated collagen fleece.18

In the included papers, the mean/median preoperative curvatures varied between 64.8° and 75.0°. The PICS surgery resulted in complete straightness of the penis in 80%–88% of men. In addition, none of the remaining patients had a penile curvature exceeding 20°.18,20,21,25 Regarding length, 2 years after the surgery Pyrgidis et al.25 reported a mean increase in penile length of 1.4 cm. Moreover, the postoperative IIEF-5 scores were recorded in 3 papers (23.5 [median],18 24.2 [mean]21 and 23.7 [mean]25). PICS surgeries resulted in an increase in the IIEF-5 scores by 13.5 points and 13.7 points.18,25

Fernández-Pascual et al.19 used a technique that was very similar to PICS. However, they performed multiple relaxing incisions in tunica albuginea and/or plaques after the IPP implantation in 27 men with PD. The mean curvature reduction in this study was 60.5°, which resulted in a mean 9.7° after the surgery.19 Penile length increased by 2.7 cm on average, reaching 14.8 cm postoperatively. The average preoperative IIEF-5 score was 11.1, but no additional data regarding this parameter were reported.19

Yachia corporoplasty after IPP placement was performed in 7 patients with a mean initial curve of 33°.27 During the procedure, (1) distal corporal body contralateral to the curve is exposed; (2) longitudinal 2 cm incision is made in the area of the greatest curvature; and (3) incision is closed transversely using interrupted sutures.27 In this study, the residual curvature was under 10° in all patients.27

The authors of one article used TEP directly before IPP implantation, in order to enhance penile length and girth, as well as reduce the curvature.26 The surgery is performed through the mobilized midline incision in the scrotum, penis is inverted at the level of the penoscrotal junction, and Buck’s fascia is mobilized along the entire length of the exposed tunica. In essence, a series of staggered incisions in the tunica albuginea is performed, along and across the penile axis to enhance length and girth, respectively.26 Moreover, in order to reduce the curvature, incisions can be concentrated in the region of maximal angulation.26 Razdan et al.26 achieved a mean reduction of 15° in penile curvature (average 20° preoperation to 5° postoperation) using the TEP in 32 patients. Crucially, the main purpose of the procedure is penile length and girth enhancement, while slight curvature reduction can be an additional benefit. Also, TEP enhanced the distal corporal length and midphallus girth, but the methodology of the measurements did not meet the inclusion criteria of this review.26

Manual modeling has been described by Lucas et al.23 and Moncada et al.24 as a method of penile curvature reduction. The procedure is performed after IPP placement and with an erect penis. The surgeon places a nondominant hand at the base of the penis, providing stabilization and protection for the closed corporotomies. Then, with a dominant hand, the operator forcibly bends the penis for 90 s in the direction opposite the point of the greatest angulation. Modeling can be repeated multiple times.23

In one study, 40 patients with an average preoperative curve of 47.8° underwent manual modeling. As a result, the mean penile angle was reduced to 37.2°.23 Very similar efficacy of manual modeling was described in another research, where the average curvature reduction of 9.7° was noted (39.4° to 29.7°).24 In this study, patients were qualified for further treatment, either incision and grafting or home modeling.24

Postoperative methods

Home modeling is a technique of postoperative penile straightening. One of the included studies used the following protocol: starting 4 weeks after surgery the patients inflate the IPP and gently bend the penis for 30 s in the direction opposite the curvature; and the exercise is performed in a 20-min cycle 3 times a day for 6 months.24

The authors recruited 76 men with a mean postoperative curve of 29.7°. They reported that at a 6-month follow-up, 94.7% of the patients had a residual angle <10°.24

The use of postoperative vacuum therapy has the potential of improving dimensional outcomes, by preventing the pseudo-capsule “coffin effect”.14 One study prospectively assessed the effects of vacuum therapy on 74 males. Vacuum device was used for 5 min two times a day for 12 weeks and the patients were followed up for 48 weeks.14 Another work by Antonini et al.15 combined postoperative vacuum therapy with a “scratch” technique, which served as a tool for intraoperative penile curvature reduction. The “scratch” technique is performed before IPP placement and consists of (1) horizontal fracturing of plaques using a nasal speculum; and (2) longitudinal “scratching” of plaques with a scalpel.15 One hundred and forty-five patients in this study also used the vacuum device for 12 weeks.15 In terms of curvature, the “scratch” method plus vacuum therapy reduced the penile angulation by 55.8° on average (65.8° on average before surgery).15

Length improved significantly over time (mean gain of 2.8 cm), and 16.7 cm length at the end of follow-up were recorded.14 The authors reported an increase in girth as well (2 cm on average). The mean penile circumference preoperatively and at the end of follow-up were 9.3 cm and 11.3 cm, respectively.14 Finally, both studies evaluated functional outcomes using the IIEF-5 questionnaire. Patients who underwent the “scratch” technique plus vacuum therapy had mean IIEF-5 scores of 9.8 before surgery and 24.1 at the end of the study.15 What is more, men who used vacuum therapy only scored median 9 points and 25 points before and after the interventions respectively.14

In order to avoid postoperative shortening of the penis, an aggressive method of IPP cylinder sizing coupled with “penile rehabilitation” can be implemented. Henry et al.22 recommended daily inflation of the prosthesis for 1 year after the surgery in 31 patients and assessed the dimensional outcomes.

The authors compared the measurements taken directly after IPP placement and at 12 months. In the process of “penile rehabilitation”, the length and girth increased by 1.0 cm and 1.1 cm (mean), respectively.22

Another method of preventing pseudo capsule “coffin effect” is an immediate activation of IPP after surgery and deflation after 2–3 weeks.16 In one study, the dimensional outcomes between an “early activation” (19 patients) and “no early activation” (27 patients) groups have been compared.16

The authors found that men who underwent early prosthesis activation had an increase in penile length of 0.4 cm, from preoperative 14.6 cm to postoperative 15.0 cm.16 Even though a preoperative circumference of the penis was not reported, the authors stated that the difference between pre- and postoperative girth was not statistically significant.16 Additionally, patients in the “early activation” group had better dimensional outcomes than those in the “no early activation” cohort.16

One randomized controlled study evaluated the effect of PDE5i after IPP implantation on functional outcomes.28 The authors included 62 men in the IPP-only group and 61 patients in the IPP + PDE5i group.28 Sildenafil was administered for one month at a dose of 50 mg per day, and the patients were observed for one year.28 The exact IIEF-5 scores were not reported, but they were illustrated on a graph. Therefore, preoperative IIEF-5 was less than 10, while at 12 months it was greater than 20 in all patients.28 In addition, males who took PDE5i had slightly better sexual function than the IPP-only group throughout the whole follow-up. This difference was statistically significant at months 2 and 3.28

DISCUSSION

IPP placement is a viable option in men with end-stage ED, when other non-invasive methods have failed.1 It usually provides high satisfaction rates and restores the erectile function.29 However, the surgery is associated with some risk of complications, including penile shortening.30 Moreover, IPP implantation only is not sufficient in correcting large penile angulations, which can still hinder sexual function of the patients. Hence, in order to avoid patient’s dissatisfaction, additional maneuvers may be implemented.

It is worth mentioning that many men undergoing IPP implantation are unable to achieve full erection and the true penile curvature cannot be properly assessed before the surgery. This may lead to scenarios, in which additional intraoperative maneuvers are not implemented, due to ethical or technical reasons. In these situations, postoperative techniques could potentially reduce the rate of re-operations and increase sexual function.

Since IPP implantation is considered a mature procedure and the last resort for ED treatment, numerous perioperative techniques have been discussed to improve function outcomes. However, these studies are often singular, small, and retrospective without control groups. What is more, there is no standardization in international societies regarding the appropriate measurements and questionnaires that should be implemented to assess the outcomes. That is why it is often impossible to compare the dimensional and functional changes between the studies and prove the superiority of one technique over another. This issue posed a significant obstacle for the authors of this review. Nevertheless, we have reviewed the literature with due diligence and assessed only the studies with similar methodologies.

Multiple pre- and intra-operative techniques that improved dimensional and satisfactory outcomes have been described in the literature. Some of these methods could not be included in this systematic review, because the studies did not meet the predefined inclusion criteria, e.g., length was measured from pubis to corona, and malleable and inflatable prosthesis groups were not divided. This is a major limitation of this review, as the excluded techniques might also be effective in improving the outcomes of IPP implantation. Nevertheless, preoperative vacuum therapy, dorsal phalloplasty, multiple-slit technique, “sliding” technique, and suprapubic lipectomy were proven to improve penile dimensions and/or erectile function.31,32,33,34,35,36

That is why we urge the andrology guidelines panels of international societies to release the recommendations on preferable penile measurements and erectile function methodology, so that the future papers report homogenous data in that matter.

In addition, the populations included in the available studies were extremely heterogeneous. Only patients with PD were recruited in most research, while a few studies excluded those men. Also, most of the studies on the topic were small and did not conduct statistical analysis to compare the true influence of the intervention. Large, prospective, and controlled trials are necessary to draw strong conclusions.

CONCLUSIONS

According to this systematic review, various intra- and postoperative techniques can be implemented to optimize dimensional and functional outcomes of IPP placement. Extreme angulation can be reduced using plaque/corporal incisions and grafting with collagen fleece, as well as the “scratch” technique with postoperative vacuum therapy. Also, in preoperative curvature of around 30°–40°, penile plication, corporoplasty, TEP, manual, and home modeling can provide good results. In addition, corporal incisions plus grafting and postoperative vacuum therapy might be the most beneficial in terms of length improvement. It is worthnoting that PICS, daily and early prosthesis activation, improved penile length, too. Moreover, postoperative vacuum therapy increases penile circumference the most. Finally, PICS, corporal incisions + grafting, “scratch” technique, vacuum therapy, and PDE5i are all associated with a significant improvement in sexual function.

AUTHOR CONTRIBUTIONS

JŁ performed the literature search, evaluated full-text articles, and prepared the original draft of the manuscript. EDB and WK designed the concept of this study and evaluated full-text articles. ŁN performed the literature search. TS was responsible for review and editing, and supervised the project. DC and CMS performed a literature search. VA performed a literature search. RC was in charge of data curation. GS was responsible for visualization of the data. GB and FC designed a methodology section. MF was responsible for visualization of the data. BR, SL and CAZ was in charge of data curation. MCS and ASH was responsible for review and editing. SB and AM designed a methodology section. FG was responsible for visualization of the data. MS evaluated full-text articles. MLE designed the concept of this study, was responsible for review and editing, and supervised the project. FDG designed the concept of this study, evaluated full-text articles, and prepared the original draft. All authors read and approved the final manuscript.

COMPETING INTERESTS

All authors declare no competing interests.

Supplementary Information is linked to the online version of the paper on the Asian Journal of Andrology website.