Chen CHENG ,Caiyue LIU ,Sunxiang MA ,Xiaohai ZHU ,Kaixiang CHENG ,Yang LIU,* ,Yingfan ZHANG,*

ABSTRACT Background Phalloplasty is still a challenging operation because of the high urethral complication rate.Several options regarding different flaps can be chosen,but there is still no perfect solution for phalloplasty in female-to-male (FTM) transgender patients.Our group tried to use prefabricated anterolateral thigh (ALT) flaps for phalloplasty to overcome the urethral complications.Methods A total of 21 transgender patients were included from 2010 to 2019.A twostage operation was performed to reconstruct the phallus.The vaginal mucosa was prefabricated as neourethra at the first stage,and the shaft of the phallus was reconstructed at the second stage.Results All reconstructed phallus survived completely in our study,and the satisfaction rate was 76.2%.The total complication rate was 57.1%.The occurrence of fistula and strictures after the operation was 52.4% and 5.8%,respectively Conclusion Prefabricated ALT flaps with vaginal mucosa have a lower stricture rate.This technique provides a simple,effective surgical option in FTM transsexuals.

KEY WORDS Vaginal mucosal graft;Urethra prefabrication;Anterolateral thigh flap;Phalloplasty;Female-to-male transsexuals

INTRODUCTION

Phalloplasty can construct a functional phallus that can achieve sexual penetration and standing urination.Phalloplasty with a single flap such as the forearm free flap or anterolateral thigh (ALT) flap has been widely used in female-to-male (FTM) transgender patients.The radial forearm free flap phalloplasty (RFFFP) is the most used technique worldwide owing to a reliable blood supply and pleasing appearance and sensation[1].The tube-in-tube technique is generally used to reconstruct the neourethra by part of the skin flap in RFFFP,which can meet the requirement of phalloplasty.Several studies have focused on improving the esthetic appearance of a neophallus[2];however,the reconstruction of the urethra is still challenging for surgeons because of the high complication rates[3-4].

Although the blood supply to the neourethra is reliable in RFFFP,several complications have been reported[5].The reconstructed urethra in the phallus is connected to an extended part of the original urethra in FTM transgender patients,thereby also increasing the complication rate in these patients.It was reported that RFFFP is associated with a urethral stricture rate of 14.1%[6].Secondary urethroplasty is technically challenging and fails in up to 50% of cases.Repeated surgery or salvage urethral exteriorization procedures can leave the patient with lifelong perineal urethrostomy[7].Moreover,the severe scar at the donor site is not easily acceptable for patients.

The ALT flap is an alternative to RFFFP for patients who do not want a forearm scar.However,a clinical study reported that the ALT technique had more urethral and other complication rates than RFFFP[6].The ALT technique is difficult in patients with thicker skin and more subcutaneous thigh fat[8]because the thick tissues will make it difficult to reconstruct the urethra with the tubein-tube technique.

Unfortunately,there is still no perfect technique to meet all the requirements for a well-functional reconstructed phallus.The high urethral complication rate has become a major challenge for plastic and reconstructive surgeons.Reconstruction of the urethra by mucosa tissues will probably get breakthrough and become the solution for urethral complications.Since 2010,our group has pioneered the use of prefabricated urethra for phalloplasty in FTM transgender patients.At the first stage,the vaginal mucosal graft was prefabricated beneath the ALT flap.Then phalloplasty with a prefabricated mucosal urethra and pedicled ALT was operated at the second stage.In this study,we shared our unique technique for phalloplasty.

METHODS

A total of 21 FTM transgender patients (aged 19-36 years;mean,25.6 years) were included from 2010 to 2019.All patients had a definite diagnosis of transgender disease and had two-stage operations.The surgical procedures are shown in Fig.1.The study conforms to the provisions in accordance with theHelsinki Declarationas revised in 2013,and all patients had signed the informed consent forms.

Fig.1 Diagram of the surgical procedures

First-Stage Operation

The first and second perforators from the descending branch of the lateral circumflex femoral artery in the ALT flap were traced by Doppler ultrasound,and the suprafascial courses were marked before surgery.The operation was performed under general anesthesia.The gynecological team performed a laparoscopic hysterectomy,salpingo-oophorectomy,and vaginectomy.Meanwhile,plastic surgeons performed mastectomy through the areola incision.The vagina mucosa was harvested from vaginectomy.Parts of the mucosa were sutured,tunneled around a 20 Foley catheter,and then opened at the anterior point of the pubic symphysis to elongate the original urethra[9].The rest of the mucosa was sutured and wrapped around a drainage tube (1.5 cm in diameter) to form the prefabricated urethra with 12-14 cm in length(Fig.2).The ALT flap was designed and marked according to the perforators,and vascular courses were marked preoperatively and followed by a subcutaneous tunnel(14 cm × 2 cm) made in the designed ALT flap.In the process of tunneling,the vascular courses were to be avoided to prevent injury.Then the tubed mucosa was introduced into the tunnel.The drainage tube was used to support the prefabricated neourethra till the second-stage operation.The patients were instructed to clean the neourethra with saline from one side of the tube to the other side daily after the operation.

Fig.2 (A) Front view of a 30-year-old FTM transgender patient before the operation.(B) The vaginal mucosa was harvested during vaginectomy.(C) Prefabricating of a 12.5-cm urethra with the vaginal mucosa.(D) Prefabricating the urethra in ALT flap at the first stage.(E) Phalloplasty with the prefabricated urethra at the second stage.(F) Urination function was properly reconstructed after the operation.

Second-Stage Operation

The second-stage operation was performed under general anesthesia six months after the first stage.The ALT flap was designed according to the first-stage operation.The square flap was harvested and rolled to form the phallus shaft.The subcutaneous fat was partly removed under a microscope to roll a neophallus if necessary.The vascular pedicle was separated towards the femoral artery,and the pedicled flap was transferred through a subcutaneous tunnel or an open incision to the perineum.The nervus cutaneus femoris lateralis from the flap was connected to the ilioinguinal nerve.The proximal prefabricated urethra was anastomosed with the urethral meatus lengthened in the first-stage operation.A catheter was kept in the urethra;meanwhile,a bladder colostomy was performed.The ALT donor-site was repaired with a skin graft.

RESULTS

Appearance of the Reconstructed Phallus

The average time of operation was 5.2 ± 0.6 h.There was no flap-related complication after the operation,and all reconstructed phallus in our study survived completely.In the follow-up minimally 12 months after the operation,the lengths of the phallus were 10-13 cm,and the diameters were 3-4.5 cm.No deformities such as“supersonic transporter”deformities[10-11]were observed in the reconstructed phallus.Totally 76.2% (16/21) of the patients were satisfied with the appearance of neophallus,and 81.0% (17/21) of patients felt acceptable for the scar.Of these,47.6% of the (10/21) patients had sensory recovery in full phallus after 12 months.

Urinary Complications

All the patients could achieve standing urination through the reconstructed phallus.The total urologic complication rate was 57.1% (12/21).There were 11 patients who had a fistula after the operation,3 of which had slight droplets during urination and healed spontaneously during 5-8 weeks.Eight patients with fistula were healed after the operation.One patient had dysuria and was diagnosed with strictures.The urologic complications of all patients are summarized in Table 1.

Table 1 Urologic complications

Fistula and Stricture Repair

Local skin flaps were used to repair the fistula six months after phalloplasty in 8 patients.All these patients healed evenly after fistula repair.One patient had a stricture in both the neourethra and the original urethra.The urethra was opened,and then free buccal mucosa was used in urethroplasty.The patient had normal urination and was followed up for six months after the operation.

Case Report

A 30-year-old FTM transgender patient was treated with our two-stage operation (Fig.1).Abundant mucosa was harvested from the vaginectomy,and a 12.5-cm neourethra was prefabricated in the ALT flap in the first stage.In the second stage,the ALT flap passed through the tunnel under the rectus femoris and sartorius muscles on its vessel pedicle and was formed in the neophallus with the prefabricated urethra.The patient recovered smoothly without any complications after the operation.The patient continued regular follow-up until 12 months after the operation,and it was shown that the neophallus had good urination function.

DISCUSSION

Phalloplasty is a challenging operation because it should fit the appearance and repair the urinary function.RFFFP is regarded as the best option and is still the most used method for phalloplasty[5,12].The tube-in-tube method can reconstruct the shaft and urethra in one-stage operation;however,the flap-made urethra had high urological complication rates,including strictures difficult to manage and usually requires more repairing operations[13].In our study,we used mucosa from vaginectomy to reconstruct the urethra in 21 FTM patients.Compared to RFFFP,the prefabricated ALT flap is an innovative method and may lower phalloplasty complication rates.The stricture rate was only 1/21 (5.8%);on the other hand,the general incidence of stricture was from 14% to 63%[14-15].Our method largely improved in stricture rate compared to other methods,including RFFFP.The differences in stricture complications were related both to tissue difference and surgical method.The fistula rate was 11/21 (52.4%) in our method,similar to that reported in previous studies[16].

One of the main reasons for the low stricture rate of our method is similar tissue used for urethra reconstruction.Histologically similar tissues are the suitable options for reconstruction and tissue repairs;therefore,the skin tissue may not be the ideal option for urethra repair or reconstruction[17].Recently,many researchers have performed complex hypospadias and urethral stricture repair after multiple failed surgeries through grafting oral mucosa,including buccal and/or lingual mucosa.These studies implied that mucosa might be a better material than skin tissues[18-20].The vaginal and oral mucosa is non-keratinized stratified squamous epithelium and they share the same histological structure[21-22].Urethral reconstruction with vaginal mucosa had many advantages over other materials.The vaginal mucosa is relatively moist,hairless,and smoother than the skin.The microcirculation within the thick and porous lamina propria can provide more blood supply than the skin,which makes the mucosa easier to survive after free grafting[23-24].Moreover,the healing process of mucosa is quicker than skin tissue and will contribute to less scar formation in the operation region[25].Since the strictures were highly related to the healing process and scar,these benefits of mucosa brought lower stricture rates in our results.

The surgical method for urethra reconstruction also contributed to the low stricture rate.In the tube-in-tube RFFFP technique,the diameter of the urethra is usually 3-4 cm.The forearm flap has to be folded twice to reconstruct the urethra and shaft,which will increase tension within the tissue and cause an adverse effect on microcirculation.All these effects would increase the stricture rate[26].In our method,the mucosa was sufficient from vaginectomy and the diameter of the urethra could be increased to 5 cm.After 6-month prefabrication and sustaining support by a drainage tube,the neourethra had sufficient vascularization and good survival condition.Moreover,with sustaining support in 6 months,the neourethral orifice may reduce the contracture rate and also contribute to the low strictures rate.

Our method was able to save the donor site damage as well.The reuse of the vaginal mucosa is“the utilization of tissue waste”.Since the donor site for the urethra can be solved by free mucosa grafts,it provides more surgical options for phalloplasty.For example,phalloplasty with a relatively thin forearm flap might be the only choice in obese patients.Our method provides a prefabricated ALT flap as the second choice,even the lower abdominal pedicled fascia flap might be an available option[22].

Our results implied that a prefabricated ALT flap was one of the best options for phalloplasty in FTM transgender patients.All reconstructed phallus survived completely due to reliable blood supply from the descending branch of the lateral femoral circumflex artery.The tube-in-tube technique of ALT flap was seldom used in FTM transgender surgery because of thick subcutaneous fat.In the series of patients in our study,the average thickness of the subcutaneous fat in the femoral anterolateral region was 1.7 cm.The diameter of the reconstructed phallus could reach 6-7 cm if the tube-in-tube technique was performed,which is obviously not an acceptable option.A lower abdominal flap was the other option for the prefabricated mucosa technique[22];however,the blood supply of the flap and sensation of reconstructed phallus were not similarly satisfactory as the ALT flap.

Our prefabricated technique was based on a pedicled ALT flap,which saved the operation time and anastomose risk compared to the free flap technique.Moreover,the donor site was hidden compared to the forearm flap.The satisfactory rate related to scar was increased to 81.0%accordingly,so we suggested that the prefabricated ALT flap with vaginal mucosa could be widely used in phalloplasty in FTM transgender patients.

CONCLUSION

Prefabricated ALT flaps with vaginal mucosa have a lower stricture rate and less donor-site damage compared to RFFFP.This technique provides a simple,effective surgical option in FTM transsexuals.

ETHICS DECLARATIONS

Ethics Approval and Consent to Participate

The study was approved by the medical ethics committee of Shanghai Ninth People’s Hospital (IRB approval no.:SH9H-2020-T373-1).All participants provided written informed consent before study enrollment.

Consent for Publication

All the authors have consented to the publication of this article.

Competing Interests

The authors declare no conflicts of interest.The authors state that the views expressed in the article are their own and not the official position of the institution or funder.

AUTHORS’ CONTRIBUTIONS

YF Z and Y L designed the overall study.C C designed and carried out study,and collected and analyzed data with CY L and SX M YF Z,Y L,and KX C performed most cases in first stage.C C,CY L,SX M,and YF Z performed most cases in second stage.Several cases were cooperated with XH Z.All the authors were involved in drafting or revising the article and they all had final approval of the manuscript.