3. Association between menstruation duration or TRM and the
clinical characteristics of the patients and the measurement data of CSD
by univariate analysis.
Interestingly, we find that the thickness of the muscular layer of the
lower segment of the uterus in the menstruation ≤7 days group is
significantly lower than that in the menstruation >7 days
group (22.67±26.88 vs. 31.77±27.84, p < 0.05). The width of
the CSD via MRI of the menstruation ≤ 7 days group is 13.27±8.14 mm,
which is significantly lower than that of the
menstruation>7 days group (14.99±8.04 mm). 47.61%
(409/859) of the patients from the TRM≥5.39 mm group has an anterior
position of the uterus and only 23.46% (19/81) of patients from the
TRM<5.39 mm group had an anterior position of the uterus. When
TRM is≥5.39 in postoperative, the TRM is thicker in preoperative
(2.79±1.87 vs. 2.16±0.93, p < 0.05) (eTable 3 in the
Supplement).
4. Multivariable linear
regression models for the association of CSD parameters and optimal
healing/menstrual improvement/TRM
The multiple linear regression results based on the entire sample are
presented in
Table 1. There is a significant negative association between CSD width
and myometrial
layer thickness of the lower uterine segment in the optimal healing
group. Additionally,
there is a significant positive association between the length and depth
of the CSD in
the optimal healing group. However, there is no significant association
between CSD
width and TRM improvement; however, a significant positive association
between
CSD depth and TRM is observed, and the uterine position is significantly
associated
with TRM improvement. Even so, the width of the CSD is significantly
associated with menstrual improvement. Additionally, there is a
significant positive association
between menstrual cycle duration and CSD length or depth in favor of
menstrual
improvement.
5. A prediction
model for the optimal healing of CSD
Multivariable logistic regression analysis is used to assess the
individualized
prediction model, and the final nomogram bases on logistic regression
analysis in the
training cohort is built. Both the thickness and width of the CSD via
MRI are negatively associated withoptimal healing (p<0.05).
CSD depth,CSD length,the menstrual cycle after cesarean section, and the
timing of surgery in the cesarean section was positively associated with
optimal healing (p < 0.05). The model derived from the
estimated β-regression coefficients of twelve variables is developed as
a nomogram (Figure 2A, eTable 4 in the Supplement). The calibration
curve of the nomogram shows adequate agreement between observation and
prediction in the training cohort and internal validation cohort (Figure
2C-2E). The Hosmer‒Lemeshow test returned a nonsignificant value (P =
0.419 in the training cohort, P = 0.963 in the internal validation
cohort). This result represent no departure from a perfect fit. The
C-index for the prediction model is 0.790 for the training cohort. The
calibration curve depicted the calibration of the model in terms of the
agreement between the observed outcome of optimal healing and the
predicted risk of optimal healing. Furthermore, the prediction nomogram
yielded a C-index of 0.823 according to internal validation of the
nomogram. The decision curve analysis for the nomogram is presented in
Figure2B.The net benefit is comparable within this range based on the
nomogram. With the nomogram model, we can provide patient treatment
recommendations.
6. The
predictive score model
The predictive score of each predictor is assigned by dividing the beta
coefficient from the logistic regression model by 0.20 (eTable 5 in the
Supplement). Thickness is given the highest score of 9.0, and CSD length
is given the lowest score of 0.5. The menstrual cycle after C-sections
is given a score of 3.0. CSD width is given a score of 6.0, and the
timing of surgery in the cesarean section is given a score of 4.0. Total
scores range from 0 to 25 points with a cutoff point of 16.5 (Table 2).
When the score ≥16.5, the patient can be predicted to achieve optimal
healing. This suggests that we can improve the surgical protocol or
change the treatment plan if the score is <16.5.