Interpretation
Passing through decidua during suturing was deliberately avoided in all
operations performed in the context of this study. A previous study by
Roberge et al. (2011) found that the locking closure technique which
passes through the decidua produced better results in terms of tissue
combination and healing.11 However, niche development
was still possible. Additionally, it is not always possible to
completely avoid crossing the decidua during such operations. It was
thus emphasized that including the decidua in measurements less than 5mm
was acceptable, while crossing the decidua with full thickness leads to
fusion and may increase niche development.4,13
A previous randomized controlled trial compared three different uterine
closure techniques (locked single-layer including the decidua,
double-layer with locked first layer including the decidua, and
double-layer with unlocked first layer excluding the decidua) in terms
of RMT; while no differences were found between the single- and
double-layer closure techniques with locked first layers, double-layer
closures without locking resulted in thicker RMT when compared to locked
single-layer closures.14 These findings supported a
hypothesis suggested by Jelsema et al. (1993) in which the locking
suture technique was thought to develop ischemic necrosis in tissues due
to increased pressure.15 However, many surgeons prefer
sutures with locking because they provide good hemostasis. Participants
in this study who received double-layer closures also received
first-layer locking. For that reason, there were no specific findings
about locking effects. While more pronounced niches were observed in
participants with double-layer closures, these differences were not
statistically significant. This may be caused by the combination of
second-layer closures with first-layer locking may have increased tissue
stress and disrupted vascularization, the idea that this was caused by
differences in technique cannot currently be proven.
On the other hand, the 3-plane niche measurements revealed that
participants who received double-layer closures had significantly higher
niche widths. However, it is difficult to measure niche width in the
transverse plane in retrovert uteri. As no other published study has
compared transverse plane measurements in this regard, this finding
cannot be thoroughly discussed.
The current literature shows that SIS is a more reliable method of
assessing cesarean delivery scar defects than TV
USG.16,17 In this study, the rates of niche
determination were 21% in TV USG and 41% in SIS. This makes it clear
that SIS provides more accurate results. While the PMB rate was 32.1%
in cases where isthmocele was detected, the rate was 5.2% among those
without. Further, a previous broad-scoped study revealed more noticeable
PMB complaints among patients in whom isthmocele was determined at least
six months after CD when compared to others.18 The
lower than expected PMB rates found in this study may be because some
patients (60; 26.7%) had not yet begun to menstruate. As such, more
accurate results can be produced by assessing patients for PMB as much
as one year after the procedure.
While a previous study that randomly divided patients into three groups
(single-layer closure of the uterus without locking, single-layer
closure with locking, and double-layer closure) found no significant
intergroup differences in terms of niche development and RMT, a trend
was found in which thicker RMT was produced via double-layer closures;
however, as opposed to the 2mm depths considered in this study, niche
presence was accepted at 1mm and deeper, while participants with
multiple pregnancies and repeat CDs were included and all niche
assessments were conducted via TV USG.9
A previous study by Tekiner et al. (2018) found no significant
differences between single- and double-layer uterine closures based on
niche assessments at the third postoperative month.19However, their study was limited in that the double-layer group had
higher rates of emergency CD, in which there is a tendency for niches to
develop at an increased rate.19 As emergency cases
were similarly distributed between groups in this study, it may be seen
that similar results were produced.
While Di Spiezio Sardo et al. (2017) compared single- and double-layer
uterine closures between participants of nine randomized controlled
trials and found no intergroup differences in terms of isthmocele, RMT
was thinner among single-layer closure patients. However, different
uterine closure techniques were used between studies, which also
implemented different niche definitions and measurement methods. For
that reason, overall results were of the low-moderate evidentiary level.
This study also found no significant intergroup differences in terms of
RMT.10
A multi-centric study with a protocol that was published in 2019 divided
a total of 2,290 patients into single- and double-layer closure groups.
Symptoms were then assessed at the third month via TV USG/SIS, while
surveys were conducted to provide long-term data. Here, single-layer
closures were made without locking and without regards to crossing the
decidua, while double-layer closures were made by passing through the
endometrium, without locking in the first layer, and continuously
without locking in the second layer. Preliminary results show that niche
presence was significantly lower among participants with single-layer
closures (79.4% vs 83%), but no differences were found in terms of
PMB.20 Although the differences were not statistically
significant, this study found similar niche rates among the single-layer
closure group (37.7% vs %45.7%; p=0.22). However, this issue must be
clarified through future prospective studies that include greater
numbers of participants.