Metoidioplasty

Metoidioplasty represents one of the variants of phalloplasty in female to male transsexuals. It involves removal of internal female genitalia such as hysterectomy, adnexectomy and vaginectomy, as well as reconstruction of the penis from hormonally hypertrophied clitoris. The native female urethra is lengthened to reach the tip of the glans and scrotum is created from labia majora with two inserted testicle prostheses. The patients should be treated hormonally for a minimum one year before surgery. Clitoris was additionally enlarged using dihydrotestosterone as a topical gel locally and applied twice a day for three months preoperatively, combined with the use of vacuum device.

The current operative technique comprise the following steps: vaginal removal, the release of the ventral chordee and clitoral ligaments, straightening and lengthening of the clitoris, urethroplasty by combining buccal mucosa graft and genital flaps and scrotoplasty with insertion of testicle prostheses. Vaginectomy is done by total removal of vaginal mucosa (colpocleisis), except the part of ventral vaginal wall close to the urethra that will be used for urethral lengthening. If persists, internal female genital organs could be removed in the same stage (hysterectomy – removal of uterus, oophorectomy – removal of ovaries) using vaginal approach. It is very important to prevent any transabdominal approach in order to preserve anterior abdominal wall for possible abdominal phalloplasty in the future.

After complete degloving, the clitoral ligaments are divided to advance the clitoris. Ventrally, the urethral plate is dissected from the clitoral bodies. Dissection includes bulbar part of the plate around the native orifice to enable its good mobility for urethral reconstruction. Since the urethral plate is always short causing the ventral clitoral curvature, it is divided at the level of the glanular corona. In this way, complete straightening and lengthening of the clitoris are achieved.

The bulbar part of urethra is created by joining the flap harvested from anterior vaginal wall and remaining part of divided urethral plate.

Additional urethral reconstruction is done using buccal mucosa graft and vascularized genital skin flaps. The buccal mucosa graft is harvested from the inner cheek using a standard technique. The length of the graft depends on the distance between the tip of the glans and the urethral meatus. The donor site is closed with a running suture. Then, graft is fixed and quilted to the corporeal bodies starting from the advanced urethral meatus to the tip of the glans. In this way, half of the urethra covering corporal bodies is created.

Urethral covering can be achieved using either labia minora flap or dorsal clitoral skin flap. Inner part of labia minora is dissected to create a flap with appropriate dimensions without detachment from the outer labial surface. This way, excellent vascularization of the flap is enabled. Flap is joined with buccal mucosa graft over a 12 to 14-Fr stent to create neourethra without tension. Only in cases of poorly developed labia minora, a well-vascularized longitudinal island flap is harvested from dorsal clitoral skin.

The penile body is reconstructed using the remaining clitoral and labia minora skin. The labia majora are joined in midline to create the scrotum. Silicone testicle prostheses (medium size, 18 to 21 cc volume depending on manufacturer) are inserted through the bilateral incisions placed at the top of labia majora.

A self-adherent dressing is used for the neophallus. Suprapubic urine drainage was placed in all cases to divert urine for 3 weeks. The urethral stent was removed after 7 to 9 days.  The average stay in hospital in this series was 3 days. Vacuum device was recommended for six months period to prevent postoperative shortening of the neophallus. 

This technique was used in 273 patients in period between May 2005 and November 2011. The length of the constructed neophallus ranged from 4 to 10 cm (mean 5.7 cm). All patients reported preserved sensation and normal postoperative erection. The length of reconstructed urethra ranged from 8.2 to 13.7 cm (mean 11.7 cm). Voiding in standing position was reported in over than 96%. Dribbling and spraying were noticed in some cases and solved spontaneously. Revisions of the mons pubis, penile skin and scrotum, as well as reposition of the testicle implants were done in less than 7% of patients. There were no other complications related to the buccal mucosa harvest site as well as postoperative bleeding, necrosis of the flap, or infection.

One of the main advantages of the technique is simultaneous removal of vaginal mucosa. The flap originated from anterior vaginal wall is very useful in lengthening of female urethra. At this spot, voiding pressure is the strongest and always presents the risk of fistula formation postoperatively. Joining of the clitoral bulbs over the lengthened urethra and additional covering with remaining surrounding tissue is considered to be a key to successful fistula prevention. 

Clitoris can be lengthened by division of its ligaments dorsally and short urethral plate ventrally. During this dissection, care should be taken to prevent injury of both neurovascular bundle and urethral spongiosal tissue.

To avoid complications described after tubularized urethroplasty, we used combined buccal mucosa graft and genital skin flaps. The application of free buccal mucosa grafts for urethral reconstruction is becoming increasingly popular in certain clinical settings. They are tough, resilient, easy to harvest, and easy to handle, and leave no visible donor site. Their histological composition makes them good grafting material. Covering of the graft can be done using either longitudinal dorsal clitoral skin flap button-holed ventrally or flap harvested from inner surface of the labia minora. In both, good vascularized tissue completely covers all suture lines preventing fistula formation in majority of cases.

Normal appearance of the external genitalia is achieved by creation of the penoscrotal angle as a male. Penile body is covered with remaining clitoral and labia minora skin. Labia majora are joined in midline to form the scrotum, in which testicular implants can be placed. 

All of our patients were managed with a single operation. In less than 5% minor complications related to urethroplasty occurred and were solved by simple procedure. Additional cosmetic corrections are always possible as a minor procedure. Most patients were satisfied with the final outcome of metoidioplasty since male genitalia appearance is achieved as well as voiding in standing position. Last but not least, neophallus is functionally though not fully adequate as it is too small to allow sexual intercourse in most of patients and requires additional augmentation phalloplasty that could be used according to patient’s sexual preferences.

– One stage metoidioplasty is a safe and timesaving procedure (approximately 2 hours; combined with vaginal removal and hysterectomy – between 2.5 and 4 hours).

– Advanced urethroplasty using combined buccal mucosa graft and genital skin flaps presents the main advantage minimizing postoperative complications.

– We consider single stage metoidioplasty to be a method of choice to create a neophallus that will satisfy the patient.

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