Robot-assisted orthotopic and heterotopic ovarian tissue transplantation techniques: surgical advances since our first success in 2000

Abstract

To demonstrate the technical advances since the time we reported the first successful case in 2000 and our modern approach to autologous transplantation of frozen-thawed human ovarian tissue. A step-by-step video demonstration of three surgical approaches was created by editing the surgical footage obtained during ovarian transplantation procedures. Academic. Three patients who previously underwent ovarian tissue harvesting and cryopreservation before gonadotoxic cancer treatments or radical cancer surgery are presented. The illustrated techniques include robot-assisted orthotopic (technique 1) and heterotopic (technique 2) approaches using the da Vinci Xi (Intuitive Surgical) robotic system and a decellularized human extracellular tissue matrix (Alloderm; LifeCell Corp.) as a tissue scaffold, as well as a percutaneous autotransplantation approach (technique 3). Successful completion of procedures without complications and ovarian graft function with demonstration of E2 production and follicle development. All cases were completed without complications. Ovarian graft function was confirmed by E2 production, follicle growth by 10-14weeks after transplantation, and later embryo development. Since our first report of successful restoration of ovarian function after orthotopic transplantation of frozen-banked ovarian tissue in 2000 (1), followed by our first reports of subcutaneous heterotopic transplantation techniques (2, 3), ovarian tissue cryopreservation followed by subsequent transplantation has become a promising fertility preservation option for young women with cancer who do not have sufficient time to undergo oocyte or embryo cryopreservation and for prepubertal girls (4, 5). The same approach also has the advantage of restoring ovarian endocrine function and fertility without a need for assisted reproduction (6, 7). In the very first successful procedure that we reported in 2000, we used conventional laparoscopy, and the tissues were reconstructed and mounted on a polycellulose scaffold (Surgicel) (1, 7). Since then, we have made significant modifications in our surgical approach with potential improvements in outcomes. Here we illustrate three main techniques of ovarian tissue transplantation resulting in the restoration of ovarian function in all cases. In the first two cases, we illustrated the robot-assisted orthotopic and heterotopic approaches using Alloderm. Robotic ovarian transplantation may increase precision, provide more delicate graft handling, and reduce the time from tissue thawing to transplantation (6, 8). Alloderm is regenerated de-epithelized human cadaver skin, which consists of several extracellular matrix components. It has been safely used in the surgery and dentistry fields for enhancing tissue regeneration and vascularization (9, 10). Furthermore, our earlier laboratory work indicated the critical role of extracellular matrix in primordial follicle growth initiation and preantral follicle growth (11, 12). Prior to our use of Alloderm as part of ovarian transplant procedures, we tested it in human ovarian xenograft models and found Alloderm to incorporate well with ovarian tissue (8). Only after that test did we adopt it for use in ovarian transplants. The utility of the extracellular tissue matrix may thus enhance our ovarian autotransplantation techniques by facilitating ovarian reconstruction and potentially improving neovascularization. In fact, we have seen improved follicle growth and response to ovarian stimulation with the use of Alloderm in our first cases (8). We use heterotopic ovarian transplantation when the pelvis is not suitable for autotransplantation due to past radiation or scarring or when there are other medical contraindications for transplantation in the pelvis. The third technique we illustrated was percutaneous heterotopic ovarian autotransplantation. This is a simple approach that can be used in surgically high-risk patients, as it is done with local anesthesia or IV sedation and without entering abdominal cavity. Additionally, same approach can be utilized when there is heightened concern that the ovarian tissue may harbor a disease that can recur, requiring close surveillance and easier removal of the ovarian graft. While ovarian endocrine function and follicle growth are restored with efficiency using the percutaneous ovarian transplants, our initial experience suggests that oocyte quality may be impaired in SC locations (2, 3, 13). Hence that technique may be more suitable when the only purpose is restoration of ovarian endocrine function. However, we have encountered recurrent live births from spontaneous conceptions following SC ovarian transplants, prompting the question of whether the grafted tissue can augment the function of in situ menopausal ovary (13, 14). While ovarian cryopreservation and transplantation may no longer be considered experimental, there are many exciting questions remaining to be answered on the full potential of this procedure.