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.