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ROBOTICS The Role of Robotic-Assisted Peritoneal Flap Augmentation in Gender-Affirming Vaginoplasty

By: Andrew Zilavy, MD, University of California, Los Angeles; Ethan Manafi, BS, University of California, Los Angeles; Arnold Chin, MD, University of California, Los Angeles; Gladys Ng, MD, University of California, Los Angeles | Posted on: 20 Feb 2024

Genital gender-affirmation surgery is a well-established component of the affirmative treatment pathway of gender dysphoria which afflicts a portion of the transgender/nonbinary community.1 The goal of the standard gender-affirming vaginoplasty is to feminize the natal-male genitalia of the appropriately selected adult transgender/nonbinary patient.1 This goal is primarily achieved by creating a neovaginal canal of adequate dimension and by using genital tissue to create a vulva with good cosmesis and a sensate neoclitoris.1 Generally, surgeons have accomplished this with a perineal operation during which the newly dissected canal between the urinary organs and the rectum is lined with genital skin.1 With over 60 years of experience demonstrating safety and efficacy of this penile inversion vaginoplasty (PIV) operation, it is reasonably considered the gold standard.1 However, the depth of the neovaginal canal created by PIV is limited by the anatomic dissection boundary of the peritoneal reflection.1 These surgical concepts are illustrated in Figures 1 and 2.


Figure 1. Perineal surgeon performs the rectovesical canal dissection of penile inversion vaginoplasty; dissection terminates at the peritoneal reflection.


Figure 2. Perineal surgeon lines the neovaginal canal with genital skin.

In 2017, Dr Lee Zhao and Dr Rachel Bluebond-Langner, translated the existing concept of peritoneal flap for creation of a neovaginal canal from the cisgender population into the transgender population.2,3 Their novel robot-assisted, abdominoperineal operation was specifically designed to augment the depth of the neovaginal cavity beyond the limit of traditional PIV.2,3 This is achieved by bringing the inverted skin tube into continuity with the peritoneum of the rectovesical pouch.2,3 Peritoneal flaps are developed and coapted to create the neovaginal apex and exclude the neovagina from the abdomen.2,3 These peritoneal flaps become the deepest part of the canal and function to extend the length of the neovaginal canal.2,3 In contrast to PIV where the anatomic boundary is the peritoneal reflection, the limiting anatomic boundary of the canal in the robotic peritoneal flap augmentation (RPFA) operation is the sacral promontory.3 These concepts regarding RPFA are illustrated in Figures 3 and 4. Due to the demonstrated safety, efficacy, and several potential improvements on the traditional PIV operation, the RPFA has already been adopted by other centers where it is performed with the single-port or Xi robot platform.2,3 A distinct advantage of the single-port platform is the low profile over the perineal surgeon, allowing for seamless simultaneous abdominoperineal surgery.2 Though the perineal PIV operation can be performed by plastic surgeons or urologists, the abdominoperineal RPFA operation depends on the robotic surgical prowess and familiarity with the android deep pelvis that urologists possess. As the demand for gender-affirming vaginoplasty, specifically RPFA, continues to increase, so will the need for involvement of the urologic surgeon in this fascinating and life-altering surgery.1 It should be noted that variations of the RPFA vaginoplasty have been described.4


Figure 3. Abdominoperineal rectovesical canal dissection is performed with the abdominal surgeon using a single-port robot while open surgery is performed by the perineal surgeon.


Figure 4. Genital skin tube is brought into continuity with the peritoneum of the rectovesical pouch. Peritoneal flaps are developed and coapted. These peritoneal flaps become the deepest portion of the neovagina and the neovaginal apex. The depth of the neovagina is limited by the sacral promontory.

While RPFA potentially improves neovaginal canal length, it introduces increased operative time, cost, and potential morbidity associated with the robot-assisted abdominal approach.3 Given the established success of the PIV method, many in the genital gender-affirmation surgery community are asking the important question: Is abdominoperineal RPFA superior to standard perineal PIV?3 Certainly, there are data to suggest that RPFA performs better in primary operations where there is limited genital skin due to congenital or feminizing hormone–induced penoscrotal hypoplasia.5 Additionally, RPFA has emerged as a sensible revision approach in cases of mild or moderate loss of neovaginal depth after standard PIV, where historically the only legitimate revision option would have been intestinal substitution vaginoplasty.1 With these points in mind, the question is better phrased: Is RPFA superior to standard PIV as a primary operation in the index patient?

To begin to answer this question, it should be recognized that cosmesis of the vulva, erogenous sensation, and neovaginal canal dimensions, in variable order, are the top 3 surgical outcome priorities as defined by the majority of patients.6 There is no reason to suspect the PIV operation and the RPFA differ in their ability to create a neoclitoris with intact erogenous sensation. However, there is reason to suspect that the operations may differ as regards neovaginal canal dimensions and the cosmesis of the vulva.3,5 It is postulated that because the depth of the neovaginal canal of the RPFA operation is not as dependent on genital skin, more genital skin may be available externally for optimal reconstruction of the vulva.3 There is no high-level evidence available to answer this question currently. Large PIV cohorts have reported cosmetic revision rates ranging from 9% to 33%.7,8 Cosmetic revision rates in the largest RPFA cohorts range from 3% to 11%.2,5

Based on the more shallow anatomic boundary of the peritoneal reflection in PIV compared to the deeper boundary of the sacral promontory in RPFA, it is postulated that RPFA allows for creation of deeper neovaginal canals.2 A robust meta-analysis in 2021 of PIV revealed an average canal depth of 9.4 cm when considering all studies that reported this outcome.9 To date, sizable RPFA vaginoplasty cohorts are limited in the literature, and there are no legitimate systematic reviews.3 The best available data as regards RPFA neovaginal depth are from Dr Lee Zhao and Dr Rachel Bluebond-Langer’s cohort of 145 patients who underwent primary RPFA vaginoplasty.2 With an average of 1-year follow-up, the average neovaginal depth was 13.9 cm.2

Several important questions remain.3 Does RPFA allow creation of deeper neovaginas?3 If RPFA does allow for creation of deeper neovaginas, does this result in a measurable and clinically significant improvement in patient-reported outcomes?3 Even with legitimate meta-analysis of certain PIV outcomes, and with long-term follow-up and outcome reporting of sizable RPFA cohorts, these questions have not been definitively answered.3 Higher-level evidence in the coming years will be required to determine how the outcomes of PIV and RPFA differ and if that difference is worth the added operative time, cost, and potential morbidity of robotic abdominopelvic surgery.3

  1. Zilavy A, Santucci R, Gallegos M. The history of gender-affirming vaginoplasty technique. Urology. 2022;165:366-372.
  2. Dy G, Jun M, Blasdel G, Bluebond-Langner R, Zhao L. Outcomes of gender affirming peritoneal flap vaginoplasty using the da Vinci single port versus Xi robotic systems. Eur Urol. 2021;79(5):676-683.
  3. Peters B, Martin L, Butler C, Dugi D, Dy G. Robotic peritoneal flap vs. perineal penile inversion techniques for gender-affirming vaginoplasty. Curr Urol Rep. 2022;23(10):211-218.
  4. Smith S, Yuan N, Stelmar J, et al. An alternative option for gender-affirming revision vaginoplasty: the tubularized urachus-peritoneal hinge flap. Sex Med. 2022;10(6):1-10.
  5. Blasdel G, Kloer C, Parker A, Shakir N, Zhao L, Bluebond-Langner R. Genital hypoplasia before gender-affirming vaginoplasty: does the robotic peritoneal flap method create equivalent vaginal canal outcomes?. Plast Reconstr Surg. 2023;151(4):867-874.
  6. Watanyusakul S. Vaginoplasty modifications to improve vulvar aesthetics. Urol Clin North Am. 2019;46(4):541-554.
  7. Gaither TW, Awad MA, Osterberg EC, et al. Postoperative complications following primary penile inversion vaginoplasty among 330 male-to-female transgender patients. J Urol. 2018;199(3):760-765.
  8. Buncamper ME, van der Sluis WB, van der Pas RSD, et al. Surgical outcome after penile inversion vaginoplasty: a retrospective study of 475 transgender women. Plast Reconstr Surg. 2016;138(5):999-1007.
  9. Bustos S, Bustos S, Mascaro A, et al. Complications and patient-reported outcomes in transfemale vaginoplasty: an updated systematic review and meta-analysis. Plast Reconstr Surg Glob Open. 2021;9(3):1-11.