Penile enhancement: A comprehensive and current perspective

Abstract

An increasing number of men with healthy and normal penises want to enlarge their penis. Therefore, this review evaluated the mental health status of men who complained of a small penis and examined the state of nonsurgical and surgical treatments for male patients seeking penile enlargement, along with a risk assessment for each. Various medical, tractional, injectable, and surgical modalities have been investigated for penile augmentation. However, the development of new products and surgical techniques, such as Penuma, and tissue engineering may yield fewer complications, good operative effects, shorter operative times, and high patient satisfaction, bringing hope to patients interested in penile enlargement.

1. Introduction

An erect penis may symbolize masculinity. It has come to represent “generosity, power, endurance, ability, courage, intelligence, understanding, domination over men, [and] possession of women” in various cultures.^[1] Over the past 2 decades, the “The bigger the penis, the better” mentality has been reinforced by an explosion of media content focused on expanding the size and thickness of the male penis. This includes everything from online advertisements to pornographic films and periodicals. Men are more concerned with their penis size and girth, and they seek methods to enhance their erections.^[2] Penis enlargement medications, elongation devices, surgical procedures, and other methods are widely accessible, but many lack the necessary oversight and are thus illegal. However, limited scientific evidence is available to support the effectiveness of these uncontrolled medicines, elongation devices, or surgical therapies in increasing penile size. Instead, these can produce several side effects. Therefore, the primary purpose of this review was to conduct a literature search to evaluate the efficacy of surgical and nonsurgical treatments for penile enlargement. In addition, it highlights the underlying motivations for penile enlargement and to provide an overview of the various medical, tractional, injectable, prosthetic, and reconstructive modalities commonly utilized in urology and plastic surgery (Table 1).

Table 1.

Summary of clinically relevant studies on different penile girth augmentation methods.

Study	Treatment modality	Design	Mean follow-up period, mo	Number of patients at baseline	Penile girth increase, cm	Complications
Kwak et al.[3]	Hyaluronic acid injection	Prospective	18	52	3.8	No serious complications
Ahn et al.[4]	Hyaluronic acid injection	Prospective	4	64	2.3	2 cases (6.3%) of mild inflammation at the site of injection were noted.
Quan et al.[5]	Hyaluronic acid injection	Retrospective	6	230	2.8	During the 6-mo follow-up, 4.3% had complications such as subcutaneous bleeding, subcutaneous nodules, and infection.
Yang et al.[6]	Polylactic acid injection	Prospective	18	23	2.7	No serious complications
Casavantes et al.[7]	Polymethyl methacrylate injection	Retrospective	Not reported	729	2.4	52% experienced palpable shaft abnormalities, and 0.4% required PMMA nodule removal.
Yacobi et al.[8]	Liquid injectable silicone (microdroplet)	Retrospective	20	324 (data on 30)	2.6	No serious complications
Aghamir et al.[9]	Vacuum erectile device	Prospective	8	30	Not reported	No serious complications
Nikoobakht et al.[10]	Traction therapy	Prospective	6	21	0.03, clinically insignificant	No serious complications
Nowroozi et al.[11]	Traction therapy	Prospective	3	44	0.02, clinically insignificant	No serious complications
Kang et al.[12]	Autologous fat injection	Retrospective	6	52	2.3	No serious complications
Shaeer[13]	Dermal fat transplantation	Retrospective	12	10	Average glans circumference increased by 16.6%	All participants exhibited edema for 7 d.
Alei et al.[14]	Porcine dermal acellular matrix graft	Retrospective	12	69	3.2 flaccid, 2.4 erect	13% experienced graft fibrosis resulting in penile retraction.
Elist et al.[15]	Subcutaneous silicone implant	Retrospective	48	400	4.9	3% required device removal because of infection, perforation, detachment, breakage, and hematoma.
Habous et al.[16]	Penile prosthesis implantation	Prospective	Not reported	133	1.04	No serious complications
Shaeer[17]	SCIAV flap	Prospective	18	40	5	No serious complications
Lei et al.[18]	The scrotal dartos flap	Prospective	6	27	3.59	Wound infection (n = 1), hematoma (n = 2), and folding (n = 1) were noted.
Siegal et al.[19]	Subcutaneous silicone implant	Retrospective	6	49	3.8	1 case of infection, 2 cases of erosion, and 4 cases of persistent flaring of the Penuma
Perovic et al.[20]	Tissue engineering with biodegradable scaffolds	Prospective	24	204	3.15	No serious complications
Djordjevic et al.[21]	Tissue engineering with biodegradable scaffolds	Retrospective	38	21	1	No serious complications

PMMA = polymethyl methacrylate; SCIAV = superficial circumflex iliac artery and vein.

2. Psychological characteristics of males seeking penile enlargement surgery

A large penis has long been celebrated as an indication of masculinity, power, prestige, fertility, and stamina. An increasing number of men are self-conscious about the size of their penis given the constant media promotion of the penis' relationship with masculinity and manhood and the widespread cultural opinion that bigger penises are better.^[22] Among 25,592 surveyed men, most respondents wanted a larger penis, and around a third wanted a longer penis.^[23] Moreover, the men surveyed expressed dissatisfaction with their height and weight in similar proportions (38% and 41%, respectively). This was true across all age categories but was most pronounced among males who thought their penis was average-sized (46%) or smaller than the average (91%) (18–65 years). Even males with average-sized penises wished to have larger penises, with studies revealing that males are often dissatisfied with their penile look, which is correlated with the frequency they overestimate their penis size.^[24] Numerous studies have shown that men who believe their penis is small are not only unhappy with their physical appearance but also have a lower sense of self, which manifests itself in their relationships.

Growing dissatisfaction among males regarding their penis size is driving the popularity of penile augmentation procedures that may lengthen or widen the male reproductive organ.^[25] Several studies have identified an increase in similar augmentation operations performed by medical experts, even though acceptability ratings for such surgeries are rarely recorded in the literature.^[25] The patients who underwent this treatment claimed various justifications for wanting to enlarge their penile circumference. Among nearly half of the participants, enhancing the self-esteem was their primary motive (and their overall sole motivation), and changing the size or shape of the penis for sexual reasons (functional/essentially enjoyable), overcoming anxieties, and curing a medical condition were included in the top 5 reasons.^[26]

3. Penis enlargement surgery, patient type, and normal penis size

Those who seek surgery and nonsurgical treatments for penile enlargement fall into 1 of 3 categories. The first group of men experienced pain because they were insecure and unhappy with the size of their penis, fearing that it was not big enough to satisfy their spouses or themselves. These men were embarrassed to have others look at their penis, especially when flaccid. Although most of these men had normal-sized penises, they tended to worry excessively and overestimate the average penises of other men. The term “small penis syndrome” describes this illness in the medical literature. Although most of these patients have less trouble maintaining sexual function, many still undergo surgical treatment. Table 2 shows patients who present for medical treatment due to small penis size. In all the cohorts, patients with below-average penises were extremely rare, and most patients had normal penises.^[1,2] The second group of male patients seeks surgery because their penis is physiologically too small. The micropenis is defined as less than 2.5 standard deviations from the average stretched length for age, mainly due to congenital endocrine dysfunction. The third group of male patients undergoes cosmetic penile contour surgery and repair for congenital and acquired causes of penile damage.^[22,26,32] These men seek various enlargement methods to increase the size and girth of their penises.

Table 2.

Findings in patient presenting to the clinic with complaints of a small penis.

Study	Number of patients	Number of normal size	Abnormal findings	Definition of normal
Mondaini et al.[27]	67	67	0	According to the authors' nomogram, above the 2.5 percentile mark
Borges et al.[28]	28	28	0	Not available
Ghanem et al.[29]	250	246	4	More than 4 cm and 7 cm were measured within 2.5 standard deviations of 12.2 cm or flaccid/stretched penile, respectively.
Nugteren et al.[30]	60	60	0	Not available
Habous et al.[31]	201	201	0	Not available

Many unproven methods to increase penis size are available on the Internet; these include lotions, pills, stretching devices, vacuum pumps, and home massage techniques. However, most are ineffective. Therefore, patients must be informed about the practice statements of various medical associations regarding enhancement procedures. These patients have tried various treatments that have not solved their penis problems and prefer surgical methods to make their penis bigger, thicker, and longer.^[1,2] When patients were asked why they wanted penile enlargement surgery, they responded with “improved confidence,” “change in penis size/appearance,” “sexual function/pleasure,” “insecurity,” and “medical issues,” with self-confidence being the most common motivation for surgery.^[32] Men believe that their actual penis size is significantly smaller than the ideal size (i.e., what they think their penis should be or what they expect it to be after penis enlargement surgery).

The normal penis size and the methods of determination of the normal penis size must be defined. Studies have been published worldwide to evaluate and establish normal penile sizes. Males from the United States, France, Germany, Korea, India, Nigeria, Scotland, Iran, Egypt, Greece, Italy, Israel, and Turkey were included in these investigations.^[26] Veale et al.^[33] conducted a systematic review pooling data from 20 studies measuring penile length and girth during flaccidity and erection, and subsequently derived nomograms for men of all ages and races (Fig. 1). A study including 15,521 men noted that, on average, penises in the flaccid and erect states were 9.16 and 13.12 cm long, respectively. Flaccid and erect girths were 9.31 and 11.66 cm, respectively. Therefore, when receiving patients with penile thickening, a thorough physiological and psychological evaluation must be performed. The physiological and psychological evaluations must be considered with patients' attitudes toward surgery to analyze the feasibility and effects of surgery and determine whether these can be achieved (Fig. 2).

Figure 1.

Penile augmentation treatment options.

Figure 2.

Nomogram for flaccid and erect girth of the penis.^[33]

4. Penis size and female and homosexual sexual function

The impact of the penis on female sexual function is predominantly through the stimulation and sexual pleasure from intercourse. Specifically, during intercourse, penile insertion into the vagina can lead to a gratifying sexual experience by rubbing and stimulating sensitive areas within the vagina, such as the G-spot and clitoris, thereby promoting vaginal lubrication and orgasms in women. In addition, the penis promotes female reproductive health. During intercourse, the penis helps remove foreign bodies and bacteria from the vagina, thereby improving the ability of a woman to withstand infections. Furthermore, frequent intercourse promotes uterine contractions and blood circulation to the reproductive organs, helping maintain health.

There is growing evidence that female sexual function, especially sexual arousal, is judged primarily by increased blood flow to the genitals and increased vaginal discharge, which can be affected by a variety of factors (psychological factors such as lack of communication between partners, depression, and unfulfilled sexual experiences, as well as certain chronic diseases, menopause, postmenopausal genitourinary syndrome, certain medications, fatigue, and weakness) leading to female sexual dysfunction.^[34]

Furthermore, female sexual dysfunction is an increasingly prevalent occurrence in young women, with a prevalence rate as high as 18.3%. A 2020 study evaluating orgasm and overall sexual function and habits among 303 American women noted that 41% of women with stable sexual partners were at risk for female sexual dysfunction.^[35] Meanwhile, a 2014 Mexican study regarding sexual dysfunction in young women highlighted that partner penile thickness/size was significant for female sexual dysfunction.^[36] A 2002 study surveying perceptions of penis size among 375 sexually active women found that 32% of women thought penis length was less significant than penis girth.^[37] In studies regarding female orgasms, 62% thought vaginal intercourse was the best trigger for orgasm. Furthermore, vaginal intercourse was thought to be achieved by grinding and stimulating sensitive areas within the vagina, with some studies suggesting that when stimulating the vagina, a larger penis may stimulate more nerve endings, thus increasing the probability of female orgasm. Similarly, some women may experience more stimulation and pleasure with a larger penis, which may enhance their libido and sexual function.^[38] These aspects are unique to penile enlargement surgery for the treatment of female sexual dysfunction. In summary, the size of the male penis is uniquely beneficial for female reproductive health, orgasm, and sexual dysfunction.

The penis is vital in sexual function and also significantly affects homosexual interactions. In male-male sexual activity, which primarily involves oral (mouth-to-genital) and anal (anal-genital) sex, the size of the penis is closely linked to sexual satisfaction. A study conducted in the United States in 2011 revealed that mutual masturbation, oral sex, and anal sex were the preferred sexual behaviors among gay and bisexual men.^[23,39] In male-male anal intercourse, the penis is inserted into the partner's rectum.^[40] The pleasure of anal sex primarily comes from stimulating the densely packed nerve endings in the anus and rectum of the receptive partner, as well as indirect stimulation of the male prostate, leading to pleasure and potential climax.^[41] In addition, a Canadian study found that penis size tends to be larger in gay than in heterosexual men, with a preference for larger sizes noted within the gay community. Research by Bogaert and Hershberger^[42] corroborated this finding in which a sample of 4000 men, those in the gay community generally had larger penises than their heterosexual counterparts. Drummond and Filiault examine the increasing significance of penis size among men who have sex with men. They argue that this emphasis is rooted in the eroticization of the body within various gay cultures, along with the ‘dual presence’ of the penis in homosexual relationships and encounters. Additionally, the researchers propose that the importance of penis size is further magnified by its prominence in the prevailing male gay culture, highlighting its role in shaping sexual dynamics and identity within this community.”^[43]

In summary, the penis is crucial in sexual function through stimulation and pleasure during heterosexual interactions. In homosexual relations, gay men predominantly achieve sexual climax through oral and anal sex. The pleasure from anal sex involves the stimulation of nerve endings and the stimulation of prostate gland, and is related to penis size. In addition, in the context of gay culture, penile size may influence sexual attractiveness, particularly among men who have sex with men. Therefore, penile size has additional significance for both heterosexual and homosexual relationships.

5. Nonsurgical approach

5.1. Injectable treatments

Regarding injectable treatments for penile girth enhancement, perhaps the foremost area of historical and contemporary research is penile subcutaneous injection therapy. Available injectable soft tissue fillers include hyaluronic acid (HA), poly l-lactic acid (PLA), polymethyl methacrylate (PMMA), calcium hydroxyapatite, and synthetic polymers such as silicone.

5.2. Hyaluronic Acid

Hyaluronic acid is a multifunctional matrix widely distributed throughout the body.^[44] It improves skin nutrient metabolism, is an excellent transdermal absorption enhancer,^[45,46] is a long-acting absorbable dermal filler with a good safety profile, and is present in multiple forms in the body, making immunization and implant rejection less likely.^[47] In a 2006 study by Kwak et al.,^[3] 41 patients received HA injection with a mean volume of 20.56 mL, among whom 14 patients had a significant increase in penile mid-axis girth from 7.48 ± 0.35 to 11.4 ± 0.34 cm at 1 month and to 11.26 ± 0.33 cm at 1 and 18 months, respectively. All patients were estimated to have better girth at 18 months. Patient satisfaction decreased significantly between 1 and 18 months. The authors attributed the decline in satisfaction to an erectile stiffness disorder because the postoperative cavernous body was covered with a softer HA. Signs of inflammation and serious adverse effects were absent in all cases.^[3] In a 2018 study by Ahn et al.^[4], 32 participants received HA treatment. The mean increase in girth was 22.74 ± 12.60 and 20.23 ± 8.73 mm in the HA and control groups, respectively. Satisfaction with penile appearance and sexual life was significantly higher in the HA groups. This concludes that HA is a safe and effective method for penile body enlargement. Although HA injections are becoming a popular modality for penile enlargement, relatively few reports of their side effects are available. In 2019, Quan et al.^[5] studied the complications associated with HA. Among these patients who received HA treatments, 4.3% experienced complications such as subcutaneous bleeding, subcutaneous nodules, and infection throughout the 6-month follow-up period. No patients experienced systemic or local allergic reactions. All complications were treated accordingly, and no further deterioration or serious sequelae were observed. Although complications of HA injection are minor and rare, they emphasize the importance of preoperative preparation and surgical techniques and that these complications can affect postsurgical patient satisfaction.

5.3. Polylactic acid

Poly L-lactic acid is a biodegradable, absorbable synthetic polymer widely used for cosmetic expansion.^[48] Poly L-lactic acid can stimulate cellular inflammatory responses by stimulating fibroblast proliferation and new collagen formation through foreign body reactions. Poly L-lactic acid particles gradually degrade through hydrolysis after injection into soft tissues, eliciting subtle volume expansion at the injection site through fibrous tissue reactions and collagen deposition.^[49,50] These bio-stimulatory features distinguish PLA from other fillers and make it potentially suited for researching the bio-stimulatory properties of thickening. In 2017, among 23 patients who underwent single-treatment PLA injections with a mean volume of 20 mL for penile girth enhancement, the mean circumference increased by 2.2 ± 0.2 cm at 3 months. The visual analog scale was used to rate satisfaction, with scores increasing from 51.6 ± 14.7 mm before the procedure to 64.8 ± 19.3 mm, 3 months after the procedure. The study also reported 5 cases of mild, transient acute encephalitis, but no severe acute cerebrovascular accidents. In conclusion, this newly developed PLA filler caused significant penile enlargement for up to 18 months and was well tolerated without serious adverse effects.^[48]

In 2020, Yang et al.^[6] compared HA and PLA fillers for penile enlargement. Patients were divided into HA injection (n = 39) and PLA filling (n = 35) groups. At 24 weeks, the average increase in penile girth was 2.1 ± 1.0 cm in the HA group and 1.6 ± 0.9 cm in the PLA group. The authors noted that both HA and PLA fillers had significantly enhanced effects in patients with micro penile syndrome 24 weeks after HA and PLA injections, and encephalitis was a severe side effect without serious adverse effects. Furthermore, for the first time, they demonstrated significant improvement in psychological distress among patients with micro penile syndrome. Although HA fillers appeared to be more effective than PLA fillers, the clinical efficacy of the 2 fillers was comparable (Fig. 3).

Figure 3.

Representative figures of polylactic acid filler injection for penile augmentation. Grossly, the fillers are uniformly distributed, and the penile shaft after injection (right) is larger than before (left): (A) immediately after injection, (B) after 6 months, and (C) after 18 months.^[48]

5.4. Polymethyl methacrylate

Polymethyl methacrylate microspheres are suspended in a vehicle such as bovine collagen or fibrin and are one of the safest non-absorbable soft tissue fillers.^[51] Beginning in 2007, Casavantes et al.^[7] administered PMMA injections to enhance penile girth in 752 men and conducted follow-up reports over 7 years. Patients had an average girth increase of 3.5 cm after 1 to 3 injections. Some irregularities in the implants were observed in approximately half of the patients, which did not cause any problems. Most patients (52%) reported nodularity, ridges, irregularities, indentations, or voids in the tissue fillers. However, significant dissatisfaction was not found during patient follow-ups, and the erectile aspect of sexual function was not affected due to the independence of the PMMA implant from the corpora cavernosum and corpus spongiosum. Although no perfect penile injectable material exists, PMMA microspheres appear to be safe, stable, and effective, and patient satisfaction is high. Injectable implants designed to increase penile circumference are becoming more widely utilized (Fig. 4).

Figure 4.

Circumcised patient before and 3 months after 1 session with 20 mL of polymethylmethacrylate.^[7]

5.5. Liquid silicone

The use of liquid silicone in the body allows for secondary contouring and for different thicknesses and diameters depending on the needs of the partner. This has led to a growing body of research on liquid silicone.^[52–54] The microdroplet technique, which involves applying very small particles of silicone (0.01–0.07 mL), was created to reduce the risk of morbidity associated with large-volume Liquid Injection System injection.^[53] In 2003, Yacobi et al.^[8] employed a series of subcutaneous injections of liquid silicone as the primary enhancement procedure in 324 men under local anesthesia. These individuals were followed up for an average of 20 months. The average penile girth measured before and after treatment was 9.5 and 12.1 cm, respectively. None of the patients reported any pain after the anesthetic effect had worn off. During the short-term follow-up, no complications were noted except for minor abrasions after the injection that resolved rapidly. Yacobi highlights the potential benefits of the microdroplet technique. However, Liquid Injection System injections for esthetic purposes have also resulted in catastrophic consequences, including silicone embolism, silicone pneumonitis, and multiorgan failure. Therefore, more rigorous studies with long-term follow-up are essential.

Overall, prospective studies with long-term follow-up and reproducible results are lacking in this field. Consequently, evidence-based clinical guidelines regarding dermal fillers for penile girth enhancement are non-existent. The off-label use of these products in patients who want to enhance their penile function should be approached with caution. Notably, most of the literature on penile enhancement comes from China, Korea, and Mexico. Additional comparative studies with long-term follow-up are required.

5.6. Vacuum erection devices

The vacuum erection device involves inserting the penis into a cylinder and applying a vacuum to create negative pressure. This negative pressure causes the corpora sinus to fill with blood. The blood then flows into the penis and is prevented from flowing out using a constriction ring at the base of the penis, thereby facilitating the maintenance of an erection during sexual activity.^[55] In a 2005 study by Aghamir et al.,^[9] 27 patients received vacuum erection device treatment. The median penile stretched lengths before and after 6 months of vacuum treatment did not differ significantly: 7.6 (6.9–9.4) and 7.9 (7–9.7) cm, respectively. At the follow-up, the patient satisfaction rate was 30%. One case of penile hematoma and one case of glans numbness were reported, both of which resolved without medical intervention. This study did not specify circumferential parameters, but with the confirmed lack of longitudinal tissue expansion, it can be inferred that circumferential expansion was also lacking. Vacuum treatment of the penis is likely an ineffective method for penile lengthening and thickening but provides psychological satisfaction for some men.

5.7. Penile traction therapy

Penile traction therapy (PTT) controls penile stretching using mechanical traction. Penile traction therapy has been used commercially and medically, with or without the support and recommendation of a clinician, using various devices with different mechanisms.^[11,56] Penile traction therapy devices usually involve fastening the head of the penis to a strap attached to 2 extension rods at the base placed at the opening of the abdomen to provide stability. The penis is gradually lengthened by applying increasing longitudinal traction along the penile axis.^[55] Two different studies have shown significant changes in mean penile length but not penile girth. Nikoobakht et al.^[10] evaluated the effect of penile-lengthening devices on penile size. Among 23 patients with a mean age of 26.5 years, the mean flaccid penile length increased from 8.8 ± 1.2 cm to 10.1 ± 1.2 cm and 10.5 ± 1.2 cm, respectively, in the first and third months of follow-up. No significant differences were observed in the circumference of the proximal penis. However, the effect was different for the circumference of the penile head (9.3 ± 0.86 vs. 8.8 ± 0.66 cm). This study demonstrated the efficacy of the penile stretching device in increasing penile length, but significant evidence of greater penile girth was not noted. No adverse effects were observed. Over a 6-month period, the second study followed 54 patients who received traction therapy 6 hours a day for 4 months. At the 6-month follow-up, significant increases in flaccid, extended, and erect penis lengths were observed, with mean increases of 1.7, 1.3, and 1.2 cm, respectively. During the nontreatment period, significant changes in penis length and girth were not observed. The International Index of Erectile Function scores indicated that device satisfaction was generally favorable, with only 4 patients discontinuing use due to mild and reversible adverse outcomes.^[11] Although the penile extender offers a favorable safety profile and is a noninvasive method to achieve sustainable penile length gain in the physiologically normal penis, the same is not true for girth augmentation and thus should not be recommended in men exclusively concerned with increasing penile girth.

6. Surgical approach

6.1. Autologous fat augmentation and dermal fat grafting

In recent decades, autologous fat injections have been widely used for cosmetic, breast augmentation, and enhancement procedures.^[57] This procedure injects excess fat cells from any part of the body into the area to be filled, and the fat cells regrow and fuse with the tissue at the site.^[58] Essentially, the fat cells grow in a different place, and because the fat cells are transplanted autologously, rejection does not occur, which fundamentally guarantees the safety of the procedure.^[59] In 2012, Kang et al.^[12] reported 52 patients who underwent phalloplasty, including autologous fat injection. At 6 months postoperatively, penile circumference enlarged by 2.29 ± 0.82 cm, with only 1 patient developing nodularity. This trial demonstrated that autologous fat is suitable for penile enlargement and has few adverse effects. In 2012, Shaeer^[13] selected 10 men who underwent a dermal fat grafting procedure. This involves making 2 ventral incisions along the ventral aspect of the corona, one on each side of the tether, and then incising the lateral glans flap on each side, bypassing the urethra and creating a plane around it, thus inserting the dermal fat graft into the existing space. The maximum circumference of the glans increased by 16.6% and 14.2% at the initial and final (10–12 months) follow-ups, respectively. The aforementioned studies using autologous fat augmentation and dermal fat grafting demonstrated considerable changes in the average penile circumference. These extensively utilized methods for penile enlargement demonstrate effectiveness and yield high patient satisfaction. Autologous fat was used earlier as an injectable filler, but its use has regressed because its resorption rates are unstable, varying from months to years, and many complications—such as irregular residual fat nodules, skin deformity, scarring, and scrotalization of the penile shaft skin—may occur.^[60] However, serious complications were not noted in the dermal fat grafting cohort (Fig. 5).

Figure 5.

Enhancing penile circumference with autologous fat injections. The harvesting cannula was moved back and forth in a fan-like motion to aspirate fat from the thigh and/or abdomen. Thigh (A) and/or abdominal fat (B) suction was performed in a fan-like pattern by moving the harvesting cannula back and forth. (C) A suction pump–assisted liposuction equipment was used to extract fat (Dominant 50; MedelaAG, Baar, Switzerland). (D) A cannula for fat injection with an 18-gauge blunt tip was placed into the Colles' fascia layer, and 1 mL of fat was injected slowly and evenly into the superficial, medium, and deep layers of the Colles' fascia by sliding the cannula back and forth. (E) Dorsal preoperative view of the penis. (F) Dorsal perspective of the penis 6 months after surgery.^[12]

6.2. Human acellular dermal matrix

Human acellular dermal matrix (HADM) is an extracellular matrix and 3-dimensional framework structure of the human dermis used in the treatment of various urologic diseases.^[61] Acellular dermal matrix (ADM) can replace autologous tissues, which can reduce secondary trauma to patients, while simultaneously reducing operation difficulty and time. Given less trauma, a simpler operation, a precise effect, and fewer complications, day surgery and outpatient surgery can be performed.^[62] In 2012, Alei et al.^[14] performed a procedure to increase penile girth in 69 patients utilizing porcine dermal decellularized grafts. At the 1-year follow-up, the mean flaccid and erect penile circumferences were 11.3 cm (8.2–13.2 cm, mean increase of 3.1 cm) and 13.2 cm (8.8–14.5 cm, mean increase of 2.4 cm), respectively. No major complications were observed. The authors highlighted several advantages of decellularized dermal matrix grafts for penile girth augmentation over autologous dermal fat grafts. This method eliminates donor-area morbidity and exhibits a significant reduction in operative time. This approach is performed through a short dorsal incision at the base of the penis such that the scar is hidden in a pubic hair–covered fold; therefore, the incision is virtually invisible. However, one disadvantage of HADM is that penile girth increases significantly in the flaccid state, but less significantly during erection. Although HADM is becoming a common modality for penile enlargement, relatively few descriptions of its complications exist. In a recent pilot study of acellular collagen matrix grafts, Xu et al.^[63] observed 78 patients treated with prostaglandin E and ADM. At the 3-month follow-up, the mean increase in penile girth was 1.1 cm. However, 47, 12, 10, 8, 7, 4, and 3 patients experienced erectile discomfort, delayed healing, insignificant enhancement, wound hematoma, foreskin edema, wound infection, and dorsal skin necrosis, respectively. Furthermore, 7 patients underwent ADM excisions. Despite a standardized surgical approach and rigorous postoperative care, the complications of combined prostaglandin E and ADM were severe, suggesting that it is not an ideal or safe method. Given the seemingly high rates of complications with ADM grafting, grafting does not appear to be viable despite the successful enhancement of penile girth.

6.3. Subcutaneous penile implant

The growing market for male genital esthetics has brought new surgical procedures, devices, and implants.^[64] One such device is a subcutaneous silicone implant called Penuma. The Penuma implant is a medical-grade silicone implant surgically implanted subcutaneously in the penile shaft to improve the girth of the penis.^[15] The longitudinal wall thickness varies from 1.5 to 2.5 cm and is available in 3 sizes: 14, 16, or 18 cm.^[65] There are 2 common approaches to Penuma implant surgery. The traditional subpubic incision technique involves a 6- to 8-cm transverse incision made above the pubic symphysis; the surgeon deepens the incision through the subcutaneous tissue to expose Buck's fascia, thereby releasing the surrounding tissue from the suspensory ligaments without affecting the ligaments. The penis is then stripped before further dissection of the distal Dartos and Buck's fasciae to expose a shiny white membrane. The subcutaneous surface of the glans is then exposed through penile intussusception, further exposing the coronal sulcus. The distal end of the penile implant can be aligned with the episcleral and glans sulcus connections before alignment. Another new type of scrotal incision implantation involves making a 1- to 2-cm longitudinal incision in the upper scrotum on the left or right base of the penis. An incision is made toward the pelvic process and deepened with a sharp peel through the subcutaneous tissue until a shiny white perineum can be seen. The penis is then bent, and additional sharp stripping is performed to expose the surface of the suspensory ligament. Surgeons who employ this new incision believe that it reduces visible skin scars, is faster, and has less postoperative swelling.^[65] In 2018, Elist et al.^[15] reported both satisfaction and adverse events in 400 patients who participated in a postoperative questionnaire. In the 400 patients, the medial circumference increased from a mean of 8.5 ± 1.2 to 13.4 ± 1.9 cm. At long-term follow-up (mean, 4 years), 72% of the patients still showed improvement, and 81% of the subjects reported “high” or “very high” satisfaction. The most common postoperative complications were seroma (4.8%), scar formation (4.5%), and infection (3.3%), whereas no patients reported any change in sexual function, erection, or ejaculation. However, 3% experienced adverse events requiring device removal. In a 2022 study by Siegal et al.,^[19] 49 patients who received Penuma implants found that the mean preoperative and postoperative flaccid girths were 9.3 ± 1.2 and 13.1 ± 1.1 cm. The mean follow-up duration was 6 months, with 1, 2, and 4 cases of infection, erosion, and persistent dilatation of the proximal Penuma coronary sulcus, respectively. They reported an infection rate of 2.0%. Elist et al. reported an infection rate of 3.3%, similar to that of inflatable and noninflatable penile implants (4.6%). However, unlike Siegal's study, Elist et al. did not apply a triple-antibiotic or rifampin solution to the implants. Previous studies have shown that infection-delaying coatings can reduce infections by up to 50%. The 2 types of studies both suggest that Penuma results in a rapid, durable increase in penile girth and generally improves the flaccidity of the penis. Other outcomes accompanying this physical change were significant improvements in self-confidence and self-esteem, as well as high levels of long-term patient satisfaction with minimal and manageable adverse events (Fig. 6).

Figure 6.

Images of a patient's penis before and after Penuma penile implantation: (A) Preoperative length, (B) preoperative length after stretching, (C) preoperative circumference, (D) postoperative length, (E) postoperative circumference, and (F) postoperative incision and drain. (Online color version available).^[19]

6.4. Penile prosthesis implantation

General penile prosthesis implantation involves prosthesis insertion into the cavernous body of the penis. The erection of the penile prosthesis simulates the physiological erection of the penis, thus allowing patients with erectile dysfunction to achieve coitus and treat severe erectile dysfunction. One of the most common complaints of patients after penile prosthesis implantation is that their erection is perceived as smaller than their natural erectile memory. After prosthetic implantation, 72% of patients reported a decrease in length. Comparing the length of these men's penises stretched before surgery and 6 months after prosthesis implantation, the length did not decrease after the procedure.^[66–68] In a 2017 study by Xie et al.,^[69] penile girth was significantly greater after placement of an inflatable penile prosthesis than after erections induced by preoperative Trimix (150 mg of papaverine, 50 μg of prostaglandin E1, and 5 mg of phentolamine in a 5 mL solution), and penile girth increased slightly 6 months postoperatively compared with 6 weeks. In 2018, Habous et al.^[16] explored whether penis size measured preoperatively and penile erections after penile implant surgery were linked in 133 patients undergoing penile implant surgery. The mean preoperative flaccid girth was 10.3 cm. After surgery, the average girth was 11.3 cm. Overall, the average increase was 1.04 cm. Penile implant surgery does not reduce penile size compared with presurgical stretching measures, instead preserving or increasing penile size for most patients. Similarly, men with inflatable penile prostheses may see a greater increase in length compared with extensible penile prostheses. Therefore, penile prosthesis surgery does not decrease penile size and may indirectly help the penis grow larger.

Surgeons often seek a combination of prosthetic implants and other procedures. In a 2014 study by Hsu et al.,^[70] 35 patients underwent extensible penile implantation. Of these, 15 (enhancement group) also underwent venous ligation of the posterior coronary plexus, deep dorsal veins, and cavernous veins. The remaining 20 men formed the control group and received only penile implants. Although preoperative penile dimension did not differ significantly between the 2 groups, a significant respective difference at 1 day and 1 year postoperatively was found in the penile circumference (128.8 ± 6.8 vs. 115.3 ± 7.2 mm and 130.6 ± 7.2 vs. 100.5 ± 7.3 mm; enhancement groups vs. control groups). The postoperative satisfaction rate was higher in the enhancement group. In 2018, Antonini et al.^[71] conducted a study of postoperative vacuum therapy after AMS™ LGX 700® inflatable penile prosthesis placement in 74 patients with medically refractory erectile dysfunction. Patients were assigned vacuum device therapy for 5 minutes twice daily. Postoperative follow-up was continued for 1 year. The dimensional and functional outcomes were evaluated. The preoperative penile length and girth were 14 and 9 cm, respectively. At the end of the study, the median penile length and girth were 17 and 11 cm, respectively. The postoperative complications included only 2 infections. As such, AMS™ LGX 700® IPP insertion and postoperative vacuum device treatment is a safe and highly satisfactory combination approach to maintain penile size.

In 2021, Khalil et al.^[72] investigated a new adjuvant surgical technique for graft-less penile girth restoration and thickening through assisted expansion of the tunica albuginea. They also evaluated whether the white membrane could be enlarged longitudinally and laterally. This is a potentially useful aid in penis enlargement as technology advances. This adjuvant technique studied by the authors succeeded in increasing the circumference at the same location of the simulated cavernous corpus cavernosum tissue through a new material with negative Poisson's rate properties (i.e., it becomes wider when stretched). The adjuvant incision enlarged the penile circumference by 50% (from 8.0 to 12.0 cm).^[73] The aforementioned novel combined technologies show that adjunctive solutions for penile enhancement and the restoration of penile volume exist. However, penile prosthesis surgery does not affect the size of the penis but may indirectly help the penis grow larger.

6.5. Skin flaps

Skin flaps are considered superior to autografts due to the uninterrupted blood supply. Given the lower probability of infection, they are considered superior to synthetic grafts. Considering the preservation structure that prevents degradation and fragmentation of the transferred tissue, they are superior to the granular fat used in injections.^[17] In 2014, Shaeer^[17] used a spin superficial circumflex iliac artery and vein flap for penile girth augmentation, with a mean increase of 5.6 cm. In total, 40 participants were satisfied with the results, but complications like edema, skin ulceration, wound dehiscence (12%), and infection (2%) were noted. Therefore, the superficial circumflex iliac artery and vein flap is a reliable option for penile girth lengthening, and flap enlargement helps preserve the intrinsic blood supply, thereby improving viability and tissue thickness.

A 2021 study by Lei et al.^[18] used a novel autologous scrotal flap (scrotal flap method) reversal to increase penile girth by rotating the scrotal flap to a loose plane between the superficial penile fascia and Buck's fascia. This surgical approach improved girth by 3.59 ± 0.80 cm. This enlargement exceeded that of most previously published surgical procedures. No serious adverse events (fibrosis, flap infection, sclerosis, or excision) were reported during the 6-month follow-up period. Based on the noted results and complications, the scrotal dartos flap approach seems to be a viable treatment for penile girth enlargement.

6.6. Tissue engineering with biodegradable scaffolds

In penile augmentation, surgery involving tissue engineering with biodegradable scaffolds is a novel technique. By creating new functional tissues from somatic cells, the circumference of the penis can be enlarged.^[74] Autologous tissue engineering using biodegradable scaffolds to dilate scrotal mycelial cells is a novel and promising approach to penile thickening that produces a steady progressive accumulation of collagen-rich, highly vascularized tissue matrix, which is very similar to deep mycelial fascia, and contributes to the investigation of stent-driven autologous tissue engineering for penile plastic surgery.^[20] Perovic et al. performed the surgery on 204 men with a mean age of 26.77 years. Biopsies of the scrotal cutaneous tissue were used to obtain fibroblasts, which were cultured until the total cell count reached at least 2 × 10.^[26] The cells were seeded onto a pretreated tubular poly(lactide-co-glycolide) scaffold and incubated for 24 hours. When the skin was compliant, the scaffold was molded and grafted with Buck's fascia; when the skin was not compliant, the scaffold was grafted underneath the neurovascular bundle. Penile girth increased by 1.9 to 4.1 cm (mean, 3.15 cm). With conservative therapy, postoperative sequelae included infections, penile skin compression necrosis, and seromas in 3, 2, and 5 cases, respectively.^[20] Autologous tissue engineering on a biodegradable scaffold is a novel, safe, and effective treatment for penile enlargement. Our initial experience with this procedure revealed a significantly lower complication rate than previously established procedures. It has also demonstrated exceptional safety, reproducibility, and superior cosmetic outcomes and can be performed under local anesthesia with an average length of stay of 2 days and an average procedure time of 1 hour.^[20] Perovic et al.^[75] also performed a second penile widening among 12 patients using a biodegradable scaffold containing enlarged autologous scrotal sarcolemma cells. Patient satisfaction was rated good (25%) or very high (75%). In a recent survey, Spyropoulos et al. conducted a study on the microscopic ultrastructural examination and surgical benefits of biodegradable scaffolds used to expand the penile circumference. Treatment consisted of 2 polylact-glycolacetic acid stents implanted with fibroblasts from laboratory-prepared scrotal tissue specimens from 21 people with an average age of 28.0 years. Autologous tissue engineering utilizing a biodegradable scaffold to induce newly formed tissue revealed the presence of vascularized sparse connective tissue with abundant collagen fibers, fibroblasts, and inflammatory cells, all of which indicated the generation of active neovascularization and fibrin. In addition, the repeat surgical technique resulted in a considerable improvement in peripenile enhancement, with a mean follow-up period of 38 months. Postoperative penile girth relaxation and erectile enhancement improved by 1.1 and 1.0 cm, respectively.^[21] According to scientists, autologous sarcolemma cell implantation on biodegradable scaffolds is a novel and promising therapeutic strategy for a realistic increase in penile circumference. This therapeutic advantage is due to the steady remodeling of neovascularization, fibroblast-like proliferation, and collagen accumulation, which are characteristics of highly vascularized normal connective tissue in the adult sarcolemma. With advances in technology, tissue engineering may be helpful in penile enlargement (Fig. 7).

Figure 7.

Repeated penile girth enhancement using biodegradable scaffolds employing biopsy of previously formed tissue. (A) The penile skin was carefully dissected. A new tissue layer was visible. (B) The scaffolds were placed next to the penile body and urethra. (C) Penile girth was equally enhanced.^[21]

7. Conclusions

Given the increasing emphasis on physical appearance, “small penis anxiety” (SPA) must be recognized and treated appropriately. Psychological distress, diminished quality of life, and impaired sexual function are crucial components of comprehensive SPA assessment. Most (96.4%) patients who underwent cosmetic procedures for SPA reported worsened or unchanged SPA symptoms.^[76] Therefore, addressing these issues is crucial for any treatment protocol. Ingenuity and device innovation are vital to technological surgical advances that can produce a more sustainable improved quality of life for patients.

Recognizing these challenges, the recent technological advancements and innovations in surgical techniques are promising. Developments in skin flap procedures, the introduction of products such as Penuma, and breakthroughs in tissue engineering have redefined the landscape. These advancements, which are characterized by fewer complications, more effective results, shorter operation time, and higher patient satisfaction, are pivotal for the development of treatment options. Moreover, the application of fat, polylactic acid, HA, and dermal transplantation during the preparatory stages of penile enlargement surgery laid the foundation for emerging materials and technologies. Innovations such as Penuma and assistive technology for the penile tunica albuginea, along with their potential for tissue engineering, are steering the field toward more promising directions. In addition, the advent and refinement of artificial intelligence, various surgical techniques, and products are anticipated not only to improve male SPA and small penis syndrome but also to enhance treatments related to female sexual function and satisfaction. With these advancements, penis enlargement surgery might become safer and more effective, benefiting from new technologies such as gene editing, stem cell therapy, nanotechnology, 3D printing, and mature biotissue engineering. These technologies aim to achieve enhancements in precision and durability.

In the future, more precise and efficient surgical and nonsurgical therapies may be developed, thereby expanding the range of options for patients with SPA. Any treatment method for SPA must encompass significant psychological components, because the treatment of SPA is not merely physiological, but a complex interplay of psychological and physical factors. This comprehensive approach ensures the adoption of more ethical, effective, and patient-centered treatment plans for managing SPA. Given the complexity of SPA, a multidisciplinary approach is essential for a thorough evaluation of a patient's eligibility for treatment. This approach should involve experts from different fields such as psychology, urology, and sexual medicine. Collaboration is crucial to comprehensively understand a patient's condition and effectively manage their expectations. Regarding expectations and patient satisfaction, the former must be managed realistically. Given the mixed results of cosmetic procedures for SPA, clear communication about the potential effects, risks, and psychological impacts of these treatments is vital. This is key to achieving patient satisfaction and reducing the risk of post-treatment dissatisfaction.

In summary, SPA treatment must adopt a holistic strategy that prioritizes psychophysical assessment, patient selection, and counseling. Recognizing the limitations of the current evidence and employing a multidisciplinary approach is crucial for better assessment of patient eligibility and meeting patient expectations. This refined approach is essential for advancing the field and ensuring effective and patient-centric care of patients with SPA.

Conflict of interest statement

No conflict of interest has been declared by the authors.