Removal and transplantation of ovarian tissue
Detailed information and a list of references can be found in Chapter 3.3 of the FertiPROTEKT book, "Indications and fertility preservation methods for oncological and non-oncological disorders", which can be downloaded free of charge.
Ovarian tissue can be removed prior to chemotherapy or radiotherapy, cryopreserved (frozen) and retransplanted later to restore fertility if there is a loss ovarian function.
Since the amount of cryopreserved tissue is not large, the grafts are often only currently active for a few years. The transplant therefore does not serve to restore long-term ovarian function, which would replace hormone replacement therapy if it was necessary, but only the temporary resumption of follicular development to achieve a pregnancy.
In general, the higher the ovarian reserve (i.e. the ovarian follicle density) in frozen and transplanted ovarian tissue, the higher the chances of pregnancy. Cryopreservation of ovarian tissue is therefore ideal for younger women or even children. FertiPROTEKT recommends 35 as the upper age limit, although this limit may also be ca. 38 years in individual cases, depending on the ovarian reserve.
There is still limited data available to assess efficacy. According to the world’s two largest case series from Denmark and the FertiPROTEKT network, with transplantations in over 100 women by 2015, the birth rate was approximately 25-30%.
The removal and transplantation of ovarian tissue requires a laparoscopy under general anaesthesia. The surgical risk is very low.
There is a risk that tumour cells are present in the ovary which are cryopreserved and later retransplanted. The risk has been estimated for various diseases. Chapter 3.3 of the FertiPROTEKT book contains detailed information about this risk. A small sample of the tissue is examined histologically when the tissue is initially removed.
The costs of removal and transplantation of ovarian tissue vary according to hospital and surgical technique and can be broken down as follows:
- Ovarian tissue removal (as a day-case procedure): ca. 1000 - 1500 Euros
- Cryopreservation (freezing and storage for 1 year): ca. 400 - 800 Euros
- Transplantation of ovarian tissue: ca. 1000 – several thousand Euros.
The costs for the removal of ovarian tissue and transplantation are covered by the health insurance in some cases. The storage of the tissue must always be paid for by the patient.
Removal of ovarian tissue is performed laparoscopically under general anaesthesia, which takes about ½ hour. About half an ovary is removed (Figure), therefore fertility is not affected by the surgery. A small sample of the tissue is examined histologically to largely exclude tumour cells.
The tissue is frozen in the removal centre itself or is transported to one of the FertiPROTEKT central cryobanks Bonn, Erlangen, Bern or Innsbruck, where it is processed and frozen.
Transplantation at a later date is performed laparoscopically. The tissue is transplanted into the pelvic wall and/or the ovary (see Figure). At least 3 months usually pass until the tissue forms follicles. Pregnancy can occur then either naturally or by artificial insemination.