Comparison with Existing Literature
Since the type of ovarian cyst may also impact the ovarian reserve29, 30, we categorized the studies into subgroups:
those focused exclusively on endometriomas and those that examined
various types of benign ovary cysts. Eight of the RCTs exclusively
included only endometriomas 3, 16, 17, 20, 21, 24, 25.
And the remaining five RCTs investigated patients with various types of
benign ovary cysts 2, 4, 19, 22, 23. Previous studies
indicated that endometriosis is also a risk factor for infertility,
which might decrease ovarian reserve since the endometriotic cyst wall
is formed by the invagination of the ovarian cortex31. A previous study found that the morphology pattern
of the ovarian tissue adjacent to the endometrioma wall did not display
standard follicular patterns. In contrast, the ovarian cortex
surrounding other benign ovarian cysts is usually normal32.
Furthermore, Park et al. presumed that the ovarian reserve is more
affected in patients with endometriomas, who tend to have pelvic
adhesion. The vascular system within the ovarian cortex or surrounding
the ovary could be injured during adhesiolysis 23.
This might explain why the decline in serum AMH levels was more
significant in the electrocoagulation group when comparing patients with
endometriomas.
On the other hand, we found that the patients with benign ovarian cysts
had a smaller decline in AMH and AFC after surgery, with no significant
difference between the electrocoagulation group and nonthermal
hemostasis group. We could surmise that if we exclude patients with
endometrioma from overall patients with non-specific benign ovarian
cysts, the result of the forest plot will show a shift to the left side,
indicating a decreased effect size in favor of the nonthermal group,
signifying no significant difference in AMH and AFC between the two
groups, even in the long-term follow-up extending to 12 months. Since
endometriomas inherently have an adverse impact on ovarian reserve,
coupled with the significant detrimental effect of electrocoaguation
during surgery in women with endometriomas, it is advisable to refrain
from employing electrocoagulation using bipolar current. Additionally,
surgeons should exercise caution to prevent injury to the ovarian cortex
injury during surgeries for endometriomas.
AMH production initiates with the growth of primordial follicles into
small antral follicles, a process that takes at least three months33. Thus, most studies 2-4, 16-20,
23, 24 measured AMH levels at the 3-month follow-up. We also compared
outcomes at 1, 6, 12 months 3, 16, 17, 19, 21, 22, 24,
25, since the longer follow-up time allows for a more comprehensive
understanding of the sustained change of AMH and AFC and addresses any
immediate postoperative concerns. Some studies 3presumed that more primordial follicles might have started to grow to
compensate for the acute ovarian damage after surgery. Therefore, the
secretion of AMH from those newly developed follicles might lead to
similar results in both treatment groups. Nonetheless, we didn’t find
the decline of AMH and AFC by electrocoagulation in endometrioma
patients to become normal after a long-term follow-up of 12 months. The
results of this present study found no significant difference in the
postoperative AMH and AFC between the two treatment groups at long-term
follow-up to postoperative 12 months for patients with benign ovarian
cysts 2, 4, 19, 23. However, the results showed the
beneficial effect of nonthermal hemostatic agents on preserving ovarian
reserve after surgery in endometrioma patients.
In order to investigate the long-term influence of the surgical
hemostatic method on the ovarian reserve, we also analyzed the outcomes
of postoperative 1, 3, 6, and 12 months. The impact on ovarian reserve
would change over time. The AMH levels might decrease transiently or
consistently after surgery 34. Previous papers have
found a significant reduction in AMH levels in patients at 1- and
3-months post-surgery 35. However, the AMH levels in
some of the patients might subsequently recover after a year36. Some studies3 presumed that more
primordial follicles might have started to grow to compensate for the
acute ovarian damage after surgery. The recovery of AMH is presumed to
be associated with reperfusion of treated ovaries 37and folliculogenesis from primordial follicles to preovulatory
follicles, which takes about 180 days 36. In
Zhang’s17 and Chung’s24 studies, the
mean AMH level of the two groups in endometrioma patients had not
decreased during 3-12 months. However, the AMH level in the
electrocoagulation group is still significantly lower than that of the
nonthermal group at 12 months post-operation. Thus, we consider that
electrocoagulation using bipolar current might have a sustained effect
on the ovarian reserve in patients with endometrioma, which may act
directly on destroying a substantial portion of primordial follicles.