The metoidioplasty, also known as metaoidioplasty or meta, is a plastic and reconstructive surgery for female to male (FtM) sex reassignment. It is also referred to as bottom surgery and is one of the two available options for gender reassignment in the FtM transgender patient and for the creation of a neo-penis, the other being the phalloplasty procedure.
The goal of the metoidioplasty is that of making congruent the physical appearance of the patient with their gender identity; it is a surgery capable of preserving both the tactile and erogenous sensation of the tissues as well as allowing for a natural erection.
The metoidioplasty exploits the clitoral hypertrophy induced by hormone replacement therapy with testosterone to transform the clitoris into a neopenis. If paired with the urethroplasty procedure, the metoidioplasty allows the patient to void while standing facilitating the inclusion of the patient in social settings and public places and for this reason, even though it generally doesn’t allow for penetrative sexual intercourse, it is a satisfactory surgery for most of the patients; only 1% of the patients report post-op dissatisfaction and request a revision surgery to improve the desired results by undergoing a phalloplasty.
The metoidioplasty usually is not a standalone procedure but is combined with other surgeries to minimize the number of general anesthesia the patient will undergo and minimize the number of hours spent in the operating room by the patient to complete the FtM transition. The surgeries that can be paired with the metoidioplasty are the bilateral hysterosalpingo-oophorectomy, the vaginectomy, the scrotoplasty, the urethral lengthening and sometimes the bilateral subcutaneous mastectomy. Moreover, the lipectomy or liposuction of the mons pubis can sometimes be performed as well at the same time, when its excessive protrusion would otherwise compromise the aesthetic results of the metoidioplasty.
Criteria for the metoidioplasty
The Standards of Care 7th edition of the World Professional Association for Transgender Care set the following criteria to have access to the metoidioplasty procedure:
- Persistent and well documented diagnosis of gender dysphoria
- In full possession of one’s faculties. Able to make a fully informed decision and to give consent for treatment.
- Age of majority in a given country.
- The absence of absolute medical contraindications (medical conditions which would make it too risky to perform the surgery).
- At least 12 continuous months of masculinizing hormone replacement therapy
- At least 12 continuous months of living in a gender role that is congruent with their gender identity.
Besides the above criteria which are set by international expert in the field of transgender medicine to avoid premature decisions when they involve invasive and non-reversible surgeries, there are also further requirements which are very important for a successful outcome and which are strictly of medical and surgical nature:
- The clitoris has to measure at least 2 cm in length
- The patient should not be obese
- The labia minora and clitoral skin should be physiologically developed to allow for use as grafts such as in urethral lengthening or as skin grafts.
- For optimal results, it is advised to wait at least 24 months from the start of hormone replacement therapy with androgens before undergoing surgery; this allows for maximum development (hypertrophy) of the clitoris before the procedure is performed.
- It might be advised by the surgeon the use of a dihydrotestosterone gel for at least 3 months before surgery, to be applied topically two times a day; the use of vacuum devices might be advised too as the mechanical traction they exert on tissues can help in maximizing the development of the clitoris.
The different surgical techniques in metoidioplasty
The metoidioplasty in female to male (FtM) sex reassignment surgery (SRS) can be performed using different surgical techniques, which lead to variable post-op results. All surgeries are usually done under general anesthesia. For the development and execution of this procedure, knowledge has been drawn from surgeries performed on male patients suffering from congenital disorders such as hypospadias and fibrous chordee.
Simple metoidioplasty or clitoral release
The clitoral release technique is the simplest type of procedure available, as well as the fastest and with less risks and complications, and the cheapest one. There is no urethral lengthening in this procedure, removing all the risks related to the modification of the lower urinary tract, but the patient won’t be able to void while standing.
The surgeon makes an incision on the skin surrounding the hypertrophic clitoris, on the lower side, and cuts off the ligament that secures the clitoris to the pubic bone (suspensory ligament) as well as cuts the clitoris crura, freeing the clitoris from all surrounding tissues and allowing for its extrusion and for visible erections to happen. Part of the labia minora and clitoral skin is excised and used as graft to make the clitoris larger in appearance.
It is still possible to undergo the urethral lengthening at a second time, but with a restricted range of possible surgical techniques available.
This technique is similar to the simple metoidioplasty but with the added step of the urethral lengthening. The urethral lengthening is performed by grafting tissues harvested from the oral mucosa or from the vaginal mucosa or from the labia minora. The urethra is then lengthened and moved forward up to the tip of the neopenis using a similar technique employed for the phalloplasty. Thanks to the urethral lengthening the patient can void while standing.
Ring flap metoidioplasty
This technique was developed in Japan by Dr. Ako Takamatsu.
There are some differences in the dissection of the clitoral chordee and suspensory ligament; the urethral lengthening presents some differences too: a ring flap is harvested from the vaginal mucosa and is used for the urethral lengthening.
The centurion technique for metoidioplasty was developed by US plastic surgeon Dr. Peter Raphael. The main difference is that it utilizes the round ligaments of the uterus to increase the girth of the neo-penis, including them into the shaft on both sides.
The metoidioplasty typically lasts 2-5 hours depending on what surgeries are performed with the metoidioplasty and on what technique is used.
If the urethral lengthening is performed during the procedure, a urinary catheter will be left in place for a period of 2-4 weeks, until the neo-urethra heals. A suprapubic cystostomy is also performed and kept until complete healing of the reconstructed urethra.
An antibiotic therapy will be prescribed and taken for about 7 days post-op.
It will be advised to use vacuum devices (negative pressure devices) for the mechanical traction of the tissues, to be used starting from the 4th week post-op up for at least 6 months and up to a couple of years post-op, to maximize the results and lengthen the neo-penis during the healing process.
Final results depend upon the surgical technique employed, the experience of the surgeon and the anatomy of the patient and the grade of hypertrophy induced by the hormone replacement therapy. Final dimensions of the neo-penis are in the range of 2,5-10 cm, with an average length of about 5cm.
Metoidioplasty with urethral lengthening generally allows the patient to void while standing, although this is not guaranteed in 100% of the cases. Penetrative sexual intercourse is hardly achievable due to the dimensions of the neopenis with all the techniques available. However, a natural erection is possible.
The execution of a metoidioplasty does not preclude a future phalloplasty, but it will limit the surgical options.
Differences between metoidioplasty and phalloplasty
The main differences between metoidioplasty and phalloplasty are the following: metoidioplasty is an easier procedure to perform, it is less invasive, has a lower rate of post-op complications, and leads to better aesthetic results when compared to the phalloplasty that employs harvested tissues from the abdomen, thigh or forearm which leave a large conspicuous scar; moreover, the metoidioplasty is less expensive, is a faster procedure (3h in the OR vs 8-10h), it has a quicker recovery and requires less further surgeries (single stage procedure). Furthermore, the metoidioplasty does not require an erectile implant since it leaves intact the clitoris erectile tissue, but it won’t allow for penetrative sexual intercourse. Lastly, the metoidioplasty guarantees in almost the entirety of the cases the preservation of the erogenous and tactile sensation with the possibility to achieve clitoral orgasms also after the surgery.
Risks and Complications
As any medical or surgical therapy, the metoidioplasty carries some risks; among the risks there are the peri-operative bleeding, infections, difficulty in surgical wound closure, loss of sensation of the neo-penis, necrosis, hyperesthesia or paraesthesia of the surgical site, urethral strictures or fistulae, inability to void while standing.
The complications involving the neo-urethra might be manageable conservatively or might require corrective surgery.
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