Female-to-Male Gender Affirmation Metoidioplasty

Marci L. Bowers,
Borko Stojanovic, Marta Bizic

Key Points

Metoidioplasty, as a single-stage gender affirmation procedure, is a good and safe option for female-to-male transsexual patients who want to avoid complex and multistage phalloplasty.

Different types of metoidioplasty can be chosen, depending on anatomy and patient preference.

The main goals of metoidioplasty are good cosmesis, the ability to void in the standing position, and preservation and/or enhancement of sexual function.

Advanced urethroplasty with a combined buccal mucosal graft and labia minora flap offers a good result with a low complication rate.

The length of the neophallus may be inadequate for penetration during sexual intercourse.

Most patients are satisfied with the final outcome of metoidioplasty as a consequence of achieving male-appearing genitalia with the ability to void while standing, in addition to preservation of sexual function.

Gender affirmation surgery (GAS) for transmen typically includes top surgery (in excess of 90%), but less commonly, genital surgery. For a variety of social, surgical, and financial reasons, bottom surgery for transmen is not as commonly chosen, especially compared with transwomen. Reasons for not accessing genital surgery include fear of complications, perceptions of less aesthetic surgical results, variable functionality of surgical results, donor-site scarring, and cost. However, as national health plans and private insurers increase coverage for transgender surgery (thereby reducing the individual’s cost), bottom surgery is on the increase. In general, the goals of female-to-male (FTM) GAS are male appearance and, when selected, the ability to stand during urination. The ability to penetrate during sexual contact is an important but secondary goal for some.1

Considerations

Patient Evaluation

The decision to move forward with genital surgery is driven by various factors and changing priorities within the transgender community. For some transmen, dysphoria with their genitalia remains an important factor prompting surgery. These men want to completely leave their female selves behind and consequently want all vestiges of female anatomy gone: the uterus, ovaries, and vagina. Even the sight of the labia can generate dysphoria. On the one hand, these individuals tend to choose phalloplasty, but not always. On the other hand, many FTM patients are realistic about their genital surgery choices and opt for some measure of affirmation, either a simple metoidioplasty (SM) alone or in combination with other available surgeries, including hysterectomy (with gonadectomy), vaginectomy, and/or scrotoplasty. Still others wish to retain their reproductive potential as “pregnant men.” Although controversial, pregnancy in posttransition males remains an available option for some, because metoidioplasty is the lone GAS that allows this possibility. Still other patients choose surgery but with sexual considerations in mind. There are transmen or genderqueer individuals who appreciate receptive penetration. Some have male partners and some do not. They may like the sexual capacity of the vagina and wish to retain it after GAS. Finally, there are logistical considerations when choosing a surgical option for transmen. Many men are simply too bulky in the mons region or attain too little growth of the clitoral phallus to allow for a satisfactory result to metoidioplasty. This is a delicate but important consideration when making a final choice. Disappointment with a neophallus that may be technically excellent but functionally buried in mons fat is a costly and unsatisfactory outcome. Monsplasty can subsequently be performed to remove fat above and around the neophallus, but this has limitations, and the patient’s expectations must be realistic.

Indications and Contraindications

These varied choices for genital surgery for FTM patients reflect the ever-changing demographics and complex needs of the transgender community and must be considered when permanent surgical choices are made. No longer is one single surgical package ideal for each candidate. This puts the onus on not only the surgeon but on the patient to devise the right combination or single procedure that addresses these very personal concerns. Additional controversy remains regarding vaginectomy in patients who seek urethral extension with their metoidioplasty. Many surgeons feel that vaginectomy allows a lower fistula in those undergoing urethral extension, although this is not supported beyond anecdotal evidence. We have not seen this increased risk of fistula; most fistulas occur distal to the vagina, with no certain explanation for why those distal fistulas are adversely affected by the lack of vaginectomy. As a result, we feel comfortable offering metoidioplasty with urethral extension, regardless of whether a vaginectomy is done. Further study is indicated. For patients in whom a resulting fistula is unacceptable, the SM without a vaginectomy can be performed with zero chance of fistula formation.

Preoperative Planning and Preparation

Selection Criteria

It is recommended that all selections of potential transgender surgical patients follow the Standards of Care for the Health of Transsexual, Transgender, and Gender Nonconforming People published by the World Professional Association for Transgender Health (WPATH).2 The standards are meant to be flexible, although in general these standards include 1 year of continuous hormone therapy and 1 year of living in the desired gender role. In addition, two letters of psychological support are recommended before the patient undergoes FTM genital surgery and GAS. Maximal clitoral growth from testosterone occurs during the first 2 years of testosterone therapy. Although growth is possible after metoidioplasty with the use of pumping and/or testosterone, we recommend 2 years of therapy before moving forward with metoidioplasty. As with any genital surgery, preoperative consultations with the patient must emphasize the details of the surgery as well as a straightforward discussion of expected outcomes and risks.

Clinical Evaluation

Of the bottom surgery choices for transmen, phalloplasty offers a larger, adult-sized penis, and for some, can provide the ability to penetrate sexually and to stand while urinating. Erotic sensation is also possible for some but not all who undergo phalloplasty. Penetration relies on insertion or activation of an insertable or inflatable device episodically, or a device that is permanently implanted within the neophallus. Significant limitations of phalloplasty include cost, donor-site scarring, a relative lack of spontaneity during sexual contact, and the necessity of a multistaged procedure.¹

Metoidioplasty, which was first described by Lebovic and Laub,³ provides an alternative to phalloplasty as a single-stage procedure. Although the neophallus will be comparatively small (range 3 to 8 cm), metoidioplasty can offer a realistic-appearing penis capable of engorgement with no loss of erotic sensation and the ability to stand to urinate, if urethral extension is chosen. The ability to penetrate is not typically attributed to metoidioplasty. That said, in discussions with individual transmen, metoidioplasty is often preferred to phalloplasty because of its organic, homegrown qualities, sexual spontaneity, and unaltered erotic sensation.⁴ Although engorged, the metoidioplasty erection is less rigid than in cisgender males because of the absence of the tunica albuginea. However, for individuals who choose metoidioplasty, penetration, where desired, is relatively possible, and by some reports, quite possible. Sexual satisfaction in both phalloplasty and metoidioplasty groups is high.⁵ Djordjevic and Bizic⁶ reported that metoidioplasty progressed to phalloplasty in only 13.52% of patients. In general, metoidioplasty is ideal in thin- to medium-built men who are relatively lacking in mons pubis adiposity. Significant pelvic fat in the mons region or a lack of clitoral hypertrophy in response to testosterone therapy will limit the apparent length of the metoidioplasty. Pumping or suctioning of the neophallus both before and after metoidioplasty has been reported to be helpful in attaining maximal length. Similarly, use of dihydrotestosterone, the active derivative of testosterone, although not widely available in the United States, has also been reported to be useful in maximizing phallic length.7 Monsplasty, a second-stage procedure, can be performed to reduce the fat around and above the metoidioplasty, allowing the penis to project more and attain a more cephalad position.

In considering metoidioplasty, the surgeon must recognize the similarities and homologies associated with male and female anatomy. The clitoris, like the penis, is composed of two paired corporeal bodies, a clitoral corona and a dorsal neurovascular sheath. Unlike males, the ventral portion of the clitoris is made up of a short, wide urethral plate. With testosterone hypertrophy, the clitoris can attain preoperative lengths of between 2 and 6 cm when measured from the coronal tip to the symphysis pubis. The head of the clitoris, although cleaved and attached to the labia minora inferiorly, can attain a size of nearly 2 cm in diameter. The shaft itself is bent downward as a result of its attachment to the labia minora, the suspensory ligaments superiorly, and the chordae below the shaft. The urethral plate is short and wide. All attachments effectively tether and curve the clitoris, limiting the length of a potential neophallus.^8,9

Metoidioplasty relies on straightening of the hypertrophied clitoris by dividing the chordae, releasing the corpora bodies from their attachment to the labia minora, and if urethral extension is chosen, elongating the short urethral plate. An SM can be selected, which allows penis creation but without the ability to stand to urinate. In the SM, the urethral plate is divided just above the original urethral opening. Metoidioplasty with urethral extension includes various methods to elongate the urethral plate and proximal urethra. These options include the buccal mucosa, labial mucosa, or the ring flap. The distal urethra is universally derived from a labial mucosal island flap, except rarely, when the available mucosal material is inadequate. The ventral portions of the urethra are derived proximally from a vaginal pedicled flap and distally from the labial mucosa.¹⁰

Surgical Techniques

All metoidioplasty methods can be combined with a hysterectomy (and generally, bilateral salpingo-oophorectomy), vaginectomy, and scrotoplasty (testicle implants) in a single-stage procedure. Results are correlated with technique and experience, although the complications from an SM are negligible). Three types of metoidioplasty will be discussed.

Simple Metoidioplasty

An SM is performed on the testosterone-enlarged clitoris/phallus. The skin around the clitoral corona is circumferentially incised, the clitoral body is degloved, and ideally, the suspensory ligaments are transected. Oblique incisions toward the symphysis pubis from the superior aspect of each labium minus transect the urethral plate, allowing access to the chordae below the shaft while also allowing enough minora skin to later enable vertical closure of the neophallus ventrally. Excess tails of the labia minora skin inferiorly are discarded. The chordae are divided transversely with electrocautery, and the levator musculature and base of the shaft are bulked and closed vertically with interrupted 3-0 Vicryl sutures. The midline approximation incorporating the levator musculature is carried superiorly to the corpora. The subcutaneous labial skin is further brought together up the shaft along the corpora until the corona is reached. The degloved corona is reattached to the minora/shaft skin with running 5-0 PDS. Finally, the outer surface of the labia minora skin is closed along the midline to form the ventral penile skin. Because the original urethral opening remains intact, the surgeon must judge how low the midline closure is in allowing urine outflow. The surgeon must also determine whether vaginectomy should be performed. A 14 Fr Foley catheter is typically placed to avoid urine contact with the raw surfaces. Simple metoidioplasty can be combined with a vaginectomy, although patients must be cautioned that residual mucosa and Skene glands can result in persistent secretions.