Interpretation
At present, it is universally acknowledged that the laparoscopic
myomectomy (LM) is a safe treatment for patients and less invasive than
the abdominal approach.(20) LM has many benefits, such as reducing pain,
reducing intraoperative blood loss, and accelerating recovery. (21)These
studies on blood loss often refer to the visible blood loss such as
intra-operative blood loss and postoperative drainage, while ignoring
the existence of hidden blood loss and its impact. Understanding and
evaluating HBL can help to evaluate the hemodynamic stability of
patients more accurately and objectively during perioperative period.
HBL has been paid more and more attention in the study of orthopaedic
surgery, and its application in gynecological surgery is still
relatively rare. HBL is also becoming one of the indicators to evaluate
one operation or compare two surgical methods for the same disease. Lei
et al. compared open posterior lumbar interbody fusion (PLIF) and
transforaminal lumbar interbody fusion (TLIF) by Wiltse approach for
lumbar degenerative disease and spinal instability from the perspective
of HBL.(22) In the field of gynecology, Zhao et al. studied the
application of HBL in laparoscopic and laparotomy in the treatment of
cervical cancer.(23) Their research reveals that HBL is seriously
undervalued. However, no one has studied the comparison between LESS-M
and CLM from the perspective of HBL.
Kim et al. have compared LESS-M and CLM in terms of surgical outcomes.
Their research suggests that the surgical outcomes (operative time,
estimated blood loss, postoperative hemoglobin drop, postoperative
hospital stay, and postoperative pain scores) were not different
statistically between these 2 groups. There was no result of HBL in
their research. (24) Our study analyzed the difference of HBL between
the two procedures and their respective risk factors.
In this study, the mean VBL was 115.4±180.6 mL in the LESS-M group.
Surprisingly, our statistical analysis showed that the HBL was
364.3±252.6 mL, which was much greater than VBL. HBL is comprised up to
74.4% of TBL in the laparotomy group. These results were similar to
those observed in the CLM group. The mean VBL was 187.9±198.5 mL for the
CLM group, the HBL was 306.8±304.7 mL (HBL is comprised up to 58.9% of
TBL). It is not difficult to make out from these data that HBL is indeed
seriously underestimated. The source of HBL has not been conclusively
determined. The mainstream view is that HBL may be associated with blood
hemolysis, extravasation of the blood into the tissues during the
operation, and blood losses during postoperative hospitalization.(25-27)
Comparing these two groups, we found that LESS-M group had more HBL.
When we compared the results between the two groups, there was a
significant difference in postoperative drainage (p=0.000).
Postoperative drainage was 36.5±150.6 in the LESS-M group, but
107.8±142.3in the CLM group. Less postoperative drainage in the LESS-M
group may lead to accumulation of blood in the abdominal cavity, leading
to an increase in HBL.
Because HBL was different between LESS-M group and CLM group, we
respectively conducted multiple linear regression analysis, to analyzed
the risk factors affecting HBL. The result indicated that the BMI
(p=0.047), pre-operative value of Hct (p=0.011), degeneration of largest
removed leiomyoma in the uterus (p=0.003) and location of largest
removed leiomyoma in the uterus (p=0.024) were risk factors in LESS-M
group. And the age (p=0.046) and cell types of largest removed leiomyoma
in the uterus (p=0.023) might increase the HBL in the CLM group.
Studies have shown that obesity causes greater postoperative blood loss,
which might be related to deeper adipose tissue.(28) From our data
combined with previous studies, we can know that higher BMI may increase
HBL, however, the specific relationship remains to be further studied.
Higher level of pre-operative value of Hct may be involved in the
process of post-operative hyperfibrinolysis which increased accumulation
of HBL in the interstitial space. (29)This statement is consistent with
our conclusion and suggests that we should pay more attention to the
post-operative blood changes. Miao et al. pointed out that the value of
HBL was positively correlated with age in total hip arthroplasty.(30)
Zhao et al. conjecture that this might be related to the loose fibrous
tissue around the uterus caused by reproductive history and aging.(23)
Hsiao et al. demonstrated that the maximum myoma diameter was a risk
factor for blood loss in myomectomy.(31) Our study also indicates that
the largest removed leiomyoma in the uterus is a risk factor for HBL. We
speculate that a larger myoma means a wider dissection area, which might
lead to an increase in the bleeding area.
Our results show that the location of the largest removed leiomyoma in
the uterus was also a risk factor, and the HBL of uterine body
leiomyomas is higher. Although the cervical myometrium is weak and close
to the blood vessels of the uterus. This may be related to the
insufficient samples of cervical leiomyoma.
Moreover, according to our data, degeneration of the largest removed
leiomyoma and cellular leiomyoma might increase HBL. Degenerative
uterine leiomyomas are often accompanied by Uterine fibroids are often
accompanied by interstitial edema and vascular morphological changes,
which may cause more blood loss.(32, 33) Studies have pointed out the
possibility of malignant transformation of cellular leiomyoma to
leiomyosarcoma.(34) We speculate that cellular uterine fibroids may have
a potential invasive capacity, thereby increasing postoperative
bleeding.
However, our study still has limitations. In more in-depth studies, we
need to increase the sample size and further explore how to assess TBL
of patients more accurately.