Biological
and functional basis of post-cesarean uterine healing
In
the uterus, healing of the post-caesarean hysterotomy does not occur in a
quiescent state, but in the midst of a biologically turbulent postpartum
period: the organ is involuting, the myometrium maintains sustained
contractions, the hormonal environment changes abruptly (estrogen and
progesterone levels drop) and the maternal metabolism tends towards a more
catabolic profile; all of which modifies the microenvironment of the wound and,
therefore, the quality of the repair. In their expert review, Bujold and Romero
emphasize that closing the uterus is not a routine step, but a surgical
procedure with long-term biological consequences: the scar must restore
continuity, perfusion and tissue alignment, but also preserve reproductive
function, where endometrial re-epithelialisation is key to avoiding defects
such as niches/isthmoceles [8]. Histologically, the scar tends to be more
fibrous (collagen) and with limited smooth muscle regeneration, which explains
why the scarred segment rarely regains the strength of the intact myometrium;
hence the remodeling phase lasts for months (even up to a year) and short
interpregnancy intervals are associated with a higher risk of complications,
because the collagen is still reorganizing and the scar has not yet "matured"
mechanically.
Risk
factors, pathophysiology, and surgical management of complicated post-cesarean
uterine dehiscence
Post-cesarean
scar dehiscence is a rare but serious cause of sepsis and secondary postpartum
hemorrhage, often characterized by an insidious and potentially
life-threatening clinical presentation. In exceptional cases, this condition is
associated with necrosis and infection of the uterine incision [1,5,7,9,10].
Several predisposing risk factors have been described, including diabetes,
emergency surgery, intraoperative infection, suture technique, hematoma at the
uterine incision site, and retrovesical hematoma formation [1,6,7]. Badr
reported a series of 23 cases of necrosis and infection of the post-cesarean
uterine incision, identifying endomyometritis and postoperative hematoma
formation as major risk factors, particularly after emergency cesarean deliveries
performed during labor and in the presence of ruptured membranes [8]. Shi
conducted a case-control study involving 408 women who underwent cesarean
delivery and identified independent risk factors associated with postoperative
sepsis. These included elevated body mass index (BMI) (OR = 2.06; 95% CI:
1.23–3.43; p = 0.006), surgical duration longer than 60 minutes (OR = 2.34; 95%
CI: 1.39–3.95; p = 0.001), and blood loss exceeding 400 mL (OR = 1.87; 95% CI:
1.12–3.13; p = 0.017) [10]. Similarly, rupture of membranes ?12 hours (OR =
2.01), labor duration ?8 hours (OR = 2.67), urinary catheter use ?24 hours (OR
= 2.79), and lack of antibiotic prophylaxis (OR = 2.16) were significantly
associated with increased risk of post-cesarean sepsis. Preoperative anemia (Hb
<100 g/L; OR = 2.08) and leukocytosis (>10 × 10?/L; OR = 2.31) were also
identified as contributing factors [10]. In the present case, the main
predisposing factors included emergency cesarean delivery performed in the
setting of ruptured membranes and active labor, conditions known to increase
the risk of postoperative infection and surgical complications. Some authors
have also suggested that rapid uterine involution in the immediate postpartum
period may negatively affect suture integrity, weaken the scar and predispose
to early dehiscence [11].
Among
surgical factors associated with postoperative complications, excessively tight
sutures during hysterorrhaphy may induce ischemia and focal myometrial
necrosis, triggering a localized inflammatory response that, particularly in
the presence of anemia, may progress to localized peritonitis. In this context,
locking or anchored sutures may increase the risk of tissue ischemia;
therefore, non-locking unidirectional sutures have been recommended, especially
in patients with predisposing conditions or early signs of tissue compromise
[4,6,9]. Ishikawa compared polydioxanone (PDS) sutures with polyglactin 910
barbed sutures in cesarean deliveries, evaluating uterine scar integrity using
three-dimensional ultrasound on postpartum day two in 54 women. Dehiscence
occurred more frequently in the PDS group (44%) than in the polyglactin group
(17.2%) (p = 0.035), with greater defect width (2.2 mm vs. 1.1 mm; p = 0.048),
suggesting increased scar vulnerability associated with barbed sutures [11].
Early dehiscence has also been linked to subsequent development of niches
(isthmoceles). Uterine dehiscence may create direct communication between the
uterine and peritoneal cavities, facilitating translocation of pathogenic
microorganisms from the upper genital tract into the peritoneal space and
increasing the risk of peritonitis and sepsis. Reported pathogens include
Escherichia coli, Klebsiella pneumoniae, Streptococcus spp., and Bacteroides
fragilis, among other Gram-negative, Gram-positive, and anaerobic organisms [4].
The clinical presentation may occur two to three weeks after delivery and, in
some cases, may be observed up to six weeks later [7,9,11]. In a review of 23
cases, the most frequent clinical manifestations were abdominal pain and
persistent fever despite antibiotic therapy for more than 48 hours, with
symptom onset occurring between 2 and 15 days after cesarean section in most
patients and between 6 and 10 weeks in a smaller proportion [3,9]. In the
present case, peritonitis and abdominal distension—findings consistent with
previously reported cases of uterine scar dehiscence and infection—developed
nine days after delivery. Several studies indicate that ultrasound is the
first-line imaging modality for the evaluation of suspected uterine rupture
[1,3-5,7,9,12]. In cases of uterine wound sepsis associated with necrosis and
endomyometritis, the indication for peripartum hysterectomy has been reported
in approximately 6% of patients. Given this clinical and surgical context,
hysterectomy was performed as a definitive intervention to control infection
and achieve adequate hemostasis [6-9]. Although surgical management is required
in patients with severe infection or peritonitis, conservative treatment with
broad-spectrum antibiotics and targeted drainage may be effective in
hemodynamically stable patients without active bleeding or advanced infection,
allowing progressive resolution and favorable clinical outcomes [13].
Physiopathological
analysis: rupture of previous uterine scar as a trigger for bacterial sepsis
Uterine
rupture over a previous cesarean section scar may represent not only a
mechanical event but also a trigger for systemic bacterial dissemination from a
previously contained focus. Recent studies have shown that the lower uterine
segment (LUS), particularly after cesarean delivery, has a vulnerable
anatomical and functional architecture characterized by reduced muscle fiber
density, decreased vascularization, and progressive thinning of the myometrium
in scarred areas [14-16]. This structure is especially prone to the formation
of defects such as niches or isthmoceles, which may act as reservoirs for
blood, mucus, or secretions, favoring an anaerobic microenvironment and
persistent bacterial colonization [17-19]. Microbiological evidence suggests
that the lower uterine segment, even in the absence of overt clinical
infection, may harbor significant bacterial colonization after delivery, with
predominance of Gram-positive cocci and Gram-negative bacilli [19-21]. These
findings are supported by histopathological analyses of uterine niches
demonstrating atrophic endocervical epithelium, chronic fibroblastic reaction,
and disorganized capillary networks without signs of acute inflammation,
supporting the hypothesis of latent uterine dysbiosis [18,19]. The type of
suture material used during cesarean section may also play a role. Absorbable
multifilament sutures, such as catgut or polyglycolic acid, have demonstrated
greater bacterial adherence and retention compared with monofilament materials
because of their capillarity and porosity [22,23]. Consequently, the scar line
within the lower uterine segment may become a surface susceptible to biofilm
formation on fibrotic tissue or foreign material, remaining clinically silent
but vulnerable to activation following structural disruption. In this context,
rupture of a sub clinically colonized uterine scar defect may act as a trigger
for massive bacterial release. Structural disruption may permit abrupt
translocation of microorganisms from the endometrial cavity into the peritoneal
space, triggering peritonitis and fulminant sepsis even in the absence of
preceding fever or clear clinical signs. Although this sequence has not been
validated in controlled clinical studies, converging anatomical,
microbiological, and histopathological evidence supports its biological
plausibility and highlights the need for targeted research. Future studies
analyzing peritoneal fluid, scar niche cultures, and bacterial typing could
help validate this hypothesis.
This
proposed mechanism may explain clinical scenarios in which no overt signs of
infection are initially identified but severe sepsis develops following uterine
rupture. It also underscores the importance of considering uterine microbiota,
surgical closure quality, and suture characteristics as key factors in the
prevention of post-cesarean infectious complications [17-20,22,23]. Comparative
analysis of published cases suggests that management of post-cesarean uterine
dehiscence exists along a therapeutic continuum primarily determined by the
extent of tissue damage and the degree of systemic infection. Patients with
localized infection and hemodynamic stability may benefit from conservative
strategies based on antibiotics and targeted drainage, whereas myometrial
necrosis, peritonitis, or severe sepsis generally require radical surgical
management following damage-control principles, including obstetric
hysterectomy. Moreover, the literature indicates that many cases evolve from
nonspecific initial presentations to septic abdomen, emphasizing the importance
of early clinical suspicion and timely imaging. Collectively, these findings
support the concept that outcomes are influenced not only by the presence of
dehiscence but also by the interaction between bacterial colonization, uterine
closure quality, and host inflammatory response—elements consistent with the
pathophysiological model proposed in the present case (Table 2).