Discussion
Laparoscopic and robot-assisted approaches may contribute to less invasive living-donor surgery in UTx in the same way that they have led to less invasive surgery for other diseases. Similarly, the use of the OV or UOV for drainage, without UV, may also contribute to less invasive living-donor surgery.
Although UTx is an option for treatment of AUFI, there are still some issues to be solved: UTx is a non-vital organ transplantation and can be considered a transplantation to improve quality of life; despite the fact that UTx is such a medical treatment, surgery for living donors takes a long time and causes a large amount of blood loss, which places a heavy burden on the living donor.
One of the reasons for the high invasiveness of donor surgery is the difficulty in handling the complex venous system around the uterus. As the veins around the uterus make a network surrounding the ureter, they are difficult to isolate in the narrow operative field of the pelvic floor without sustaining damage. As a solution to this challenge, techniques in which the OV and/or UOV are used, instead of the UV, as drainage veins have been developed. In the UTx cases included in this review, only the UOV and OV were used, instead of the UV in each approach of living-donor surgery. With the exception of the open approach, the blood loss tended to be lower in non-UV preserved cases than in the UV preserved cases. This suggests that not using UV may contribute to a less invasive living-donor surgery for UTx.
On the other hand, there are concerns about the use of the UOV and OV as drainage veins. The first is whether these veins are sufficient for blood flow in the gestational uterus. Many pregnancies and live births have been reported after radical trachelectomy (RT), a fertility preservation treatment for cervical cancer in which the venous blood flow of the uterus is dependent on the UOV and OV, as well as UTx, using the UOV and OV only.30 Considering this fact, the venous flow required by the gestational uterus is preserved even if only the UOV and OV are used as drainage veins. In addition, considering that there have already been reports of live births in UTx without using the UV as a drainage vein,8,20 the use of the UOV and OV should be considered as an option for living-donor surgery. The second concern is the effect of vascular anastomosis. In UTx, donor vessels are mainly anastomosed to the recipient’s external iliac vein, but it is unclear how the uterine enlargement caused by pregnancy affects the anastomosis sites and vessels. In particular, when the UOV is used, the effect of uterine augmentation during pregnancy is likely to be significant because of the short length of vessels that can be removed. It is hoped that more data about these points will be collected.
When the OV is used as a drainage vein, the impact of an enlarged gestational uterus may be lessened because a longer vessel can be removed than with UOV, but donor oophorectomy is unavoidable, and the associated complications must be considered. Bilateral oophorectomy in premenopausal patients results in the abolition of ovarian function and surgical primary ovarian insufficiency. Increased subjective symptoms, such as hot flashes and increased incidence of osteoporosis, cardiovascular disease, and non-alcoholic fatty liver, due to primary ovarian insufficiency have been reported.31 In addition, there have been some reports of an increase in all-cause mortality of about 28% in the absence of hormone replacement therapy for these patients.32,33 As UTx is performed to improve quality of life, complications in living donors should be avoided as much as possible, and a worsening living-donor prognosis is unacceptable. The use of the OV as a venous vessel on the premenopausal donor, where ovariectomy is inevitable, should be discussed.
Laparoscopic and robot-assisted approaches have advantages, such as improved magnification and small, minimally invasive wounds. These characteristics are being applied to clinical practice in UTx with the possibility of contributing to less invasive living-donor surgery. Previous reports comparing laparoscopic and open approaches for radical hysterectomy, in which the uterine artery and veins are handled as well as UTx living-donor surgery, have reported less intraoperative blood loss with laparoscopic approach than with open approach.34 In addition, robot-assisted approach has already been used in other organ transplant surgeries.35 It has already contributed to minimising invasive living-donor surgery and is, therefore, considered feasible. In this review, the laparoscopic and robot-assisted living-donor UTx operations also tended reduce blood loss compared to the open approach. There was also a tendency for patients to be discharged earlier with the robot-assisted approach than with the open approach. These findings suggest that the laparoscopic and robot-assisted approaches may contribute to less invasive UTx in the future.
On the other hand, the disadvantages and complications of laparoscopic and robot-assisted approaches need to be considered. Fourteen cases of robot-assisted surgeries were reported, but the average operative time was longer than that of the open approach. Temporary alopecia has been reported as a complication related to intraoperative positioning in robot-assisted approach.24 In addition, the main goal of UTx is to achieve live birth after transplantation. Although many live births have been reported for the open approach, partly because of the small number of procedures performed, only two live births have been reported for the laparoscopic and robot-assisted approach UTx. A long-term report on mental status after UTx17 found no clear results on how live birth affects mental status, but it is thought that live birth could affect the mental status of living donors. Although minimally invasive techniques for living donors are required, these need to be developed with the objectives of UTx in mind.
Open approach has a higher incidence of surgical complications and graft failure than minimally invasive approaches. However, the open approach has been performed since the inception of UTx, and surgical outcomes from that time are also included in this review. In addition, the robot-assisted approach is utilised in countries that perform more UTx by the open approach by surgeons who have sufficient experience with UTx surgery. The differences in clinical and operative outcomes between each approach may be influenced by these factors, which do not lead directly to the conclusion that the open approach is inferior to minimally invasive approaches. Further accumulation of data with regards the clinical outcomes of each approach is essential.
UTx from deceased donors has been clinically applied as a fundamental solution to the risks of living donors, and there are reports of live births after UTx from deceased donors.36,37 To investigate UTx from a deceased donor, basic research has also been conducted.38 However, this technique has challenges such as hormone replacement therapy for postmenopausal donors and difficulties in assessing the detailed uterine vasculature. The effects of these factors on graft implantation and live birth need to be examined. There are also many issues that need to be considered, such as what criteria are suitable for deceased donors for UTx and what surgical procedures for organ harvesting, such as hysterectomy, may be appropriate.
Limitations are present in this review. As this is a retrospective review, various confounding factors may be included, and it is not possible to say directly which approach is superior. Statistical comparisons with laparoscopic and robot-assisted approaches are particularly difficult to conduct because of the small number of procedures performed. In addition, this review only included original articles that met the inclusion criteria retrieved by PubMed. However, there are some articles that include unpublished data, such as live birth after laparoscopic UTx in India, and some press releases about the implementation of UTx in other countries.5,39,40 If such information is included, the results may differ from those of this review.
This literature review on UTx living-donor surgical approaches, preserved veins, and operative and clinical outcomes was conducted with a focus on the laparoscopic approach and robot-assisted approach. Laparoscopic and robot-assisted approaches may contribute to less invasive living-donor surgery in UTx in the same way that they have led to less invasive surgery for other diseases. Similarly, the use of the OV or UOV as a drainage vein, without UV, may also contribute to less invasive living-donor surgery. However, there are few reports of live birth—the ultimate goal of UTx—with these new techniques. The application of these techniques needs to be thoroughly discussed.