Current surgical treatment of uterine isthmocele: an update of existing literature.

The prevalence of uterine isthmocele, also known as a uterine niche, has risen in parallel with increasing cesarean section (CS) rates, affecting approximately 60% of women depending on their history of cesarean deliveries. This condition, now categorized as cesarean scar disorder (CSD) by the “Delphi consensus,” is characterized by one primary or two secondary symptoms. Diagnosis can be made through transvaginal ultrasound, sonohysterography, hysteroscopy, or magnetic resonance imaging (MRI). Management of isthmocele may involve pharmacological or surgical interventions. This review aims to provide a thorough analysis of the surgical management options, focusing on postoperative symptom relief, intraoperative and postoperative complications, length of hospital stay, and impact on secondary infertility. PubMed was comprehensively searched for observational studies from inception to 07.08.2024. Surgical treatments include hysteroscopic resection, laparo- scopic procedures, and vaginal approaches, all of which offer comparable symptom relief. However, the vaginal approach is associated with a longer hospital stay. The robotic-assisted approach shows promising results but lacks extensive data. Among surgical options, hysteroscopic treatment has the fewest complications but is generally avoided when residual myometrial thickness (RMT) is less than 3 mm. While many CSDs remain asymptomatic, and some women with uterine isthmocele may not wish to conceive, symptomatic patients or those desiring to conceive may benefit from surgical intervention. The choice of procedure should be based on individual patient characteristics, particularly RMT, to define the most appropriate surgical approach.

Niche · Isthmocele · Surgery · Management

A uterine niche, also known as isthmocele, cesarean scar defect, or uterine diverticulum can be observed after an incomplete healing of the cesarean scar. In 1969, Poivedin et al. first described a “uterine depression” at the site of a cesarean section (CS) [1 ]. In the years that followed, vari- ous terms were employed to describe this defect and various symptoms related to this disorder have been proposed. It is only recently that a “Delphi” consensus has been reached regarding the constellation of symptoms associated with a uterine niche, leading to the condition being formally named Cesarean Scar Disorder (CSD) [2 ]. CSD is defined as a uterine niche, combined with at least one primary or two secondary symptoms. The primary symptoms include postmenstrual spotting, pain during uterine bleeding, techni- cal issues with catheter insertion during embryo transfer and the secondary refer to unexplained infertility combined with intrauterine fluid [2]. The most prevalent method for diagnosing uterine defects is the conventional two-dimensional transvaginal ultrasound (TVUS), which may be performed with or without injection of contrast agents [3, 4]. Additionally, other research groups advocate for the utilization of three-dimensional transvaginal ultrasound (3D TVUS), sonohysterography, hysteroscopy, or Konstantinos Stavridis and Dimitrios Balafoutas joined first authorship. * Konstantinos Stavridis [email protected] 1 2nd Department of Obstetrics and Gynecology, “Aretaieion” University Hospital, Athens, Greece 2 Department of Obstetrics and Gynecology, Spital Männedorf, 8708 Männedorf, Switzerland 3 Department of Obstetrics and Gynecology, University Hospital of Würzburg, Josef-Schneider -Str. 4, 97080 Würzburg, Germany 14 Archives of Gynecology and Obstetrics (2025) 311:13–24 magnetic resonance imaging (MRI) as alternative diagnostic approaches for identifying unhealed uterine defects [2, 5, 6]. Currently, there are no specific guidelines for the diagno- sis of a uterine niche. However, Jordan et al., in their Del- phi consensus, proposed that the use of gel or saline might enhance the diagnostic accuracy for this defect. According to their research, sonographic characterization of the lesion involves identifying an anechoic defect within the myome- trium with a minimum depth of 2 mm [7]. Nonetheless, prior studies have employed lower cut-off values for defining this defect [8]. The prevalence of uterine isthmocele has risen notably with the increasing frequency of cesarean sections world- wide. Current estimates suggest that this condition affects between 19 and 88% of women, depending on the number of prior CS [8, 9]. Indeed after a CS, a niche can be observed in about 60% of women and 25% of them may present a large defect with a residual myometrium thickness (RMT) less than 3 mm. Between 30 and 40% of women with a uterine niche following a CS will exhibit symptoms, with postmen- strual spotting being the most prevalent [2, 8]. The management of CSDs can be addressed through either pharmacological or surgical methods [10]. Data on medical management remains limited. One study pro- vides evidence supporting the use of oral contraceptives [11], while a randomized trial advocates for the use of a levonorgestrel-releasing intrauterine system [ 12]. Thus, this paper aims to illuminate the surgical management of a uterine niche. Currently, several different methods of CSDs surgical repair are available, including hysteroscopy, vagi- nal repair, standard or robotic-assisted laparoscopy, and a combinational approach. Recent literature offers no specific guidelines recommending one approach over another for the management of CSDs [13, 14]. Therefore, this review aims to offer a thorough update on the surgical management of cesarean scar defects (CSDs), including an evaluation of the indications for each treatment method, surgical outcomes related to symptom relief, intraoperative and postoperative complications, and the incidence of subsequent pregnancies following repair.

PubMed (Medline) was searched to identify observational studies published from inception to 07.08.2024 that were related to uterine niche repair. The search was limited to English papers and human studies. The following search terms were used: ‘cesarean scar defect, OR ‘uterine niche, ‘cesarean scar dehiscence, OR ‘cesarean scar isthmocele, OR cesarean scar diverticulum’, OR ‘cesarean scar pouch’. We further hand-searched the citations of the retrieved eligi- ble papers to identify additional publications that might have been missed during the initial search. Case reports, case- series including less than 3 participants, editorials, reviews and conference papers were excluded. The primary outcome of this review was symptoms relief, defined as improvement in postmenstrual abnormal uterine bleeding (PAUB) or improvement in pelvic pain and second- ary outcomes included postmenstrual blood loss, length of hospital stay, secondary infertility improvement, and cesar- ean scar recurrence. From each study, the following information was abstracted: first author, publication year, study location, study type, sample size, age (mean ± SD), BMI, previous number of CSs, surgical outcomes in terms of patient relief of symptoms, intraoperative complication, postoperative complications, hospital length of stay (mean ± SD).

Hysteroscopic resection Technically, for bleeding control purposes, most studies reported resection of the inferior and posterior edge of the CSD, while the bottom part was fulgurated or electrocau- terized with a roller-ball electrode [15– 24]. Other research groups chose to resect only the inferior edge of the CSD, yet they achieved comparable intraoperative and postoperative outcomes [25–28]. The primary outcomes investigated in most studies were PAUB and secondary infertility improvement. The first hysteroscopic resection for the repair of a uterine niche was reported by Fernandez et al. In their study, hys- teroscopic resection of the abnormal uterine fibroid tissue successfully resolved postmenstrual bleeding in all patients. Notably, among the entire cohort, two of four patients who were infertile prior to the procedure subsequently achieved pregnancy, representing a 50% success rate in this subgroup [29]. In 2011, Wang et al. retrospectively studied 57 patients who were offered resectoscopic management of abnor - mal uterine bleeding following CS. While the mean dura- tion of preoperative menstrual bleeding was significantly longer than that of postoperative bleeding (12.9 ± 2.9 days vs. 9.4 ± 4.1 days, respectively; p < 0.001), only 59.6% of patients reported an improvement in symptoms after surgery. Notably, this improvement was more commonly observed in patients with an anteflexed uterus [30]. Similarly, a rand- omized trial by Vervoort et al. reported significant decrease in menstrual blood loss and improved quality of life after hysteroscopic resection, albeit intermenstrual bleeding and dysmenorrhea persisted even after surgery [24]. In 2014, a large prospective cohort study involving 120 patients found that 80% experienced complete relief from symptoms, 15Archives of Gynecology and Obstetrics (2025) 311:13–24 including uterine bleeding and chronic suprapubic pel- vic pain, while 7% saw improvement and 13% reported no change. The researchers concluded that the operative hysteroscopy strategy, defined as isthmoplasty, could be considered for symptomatic patients, although long-term outcomes, such as the risk of uterine rupture in future preg- nancies, remain inadequately studied [26]. In a recent large, randomized trial comparing the 26Fr resectoscope with the 16Fr miniresectoscope for isthmocele repair, the results demonstrated a low incidence of PAUB of only 2.9%, simi- lar in both groups. Additionally, pelvic pain was effectively managed in 92.6% of patients. Overall, the study found a low rate of postoperative complications, with only 1.9% of patients experiencing issues such as cervical laceration, nau- sea, or the need for hospitalization exceeding 4 h [31]. Overall, PAUB was effectively managed in 59,6% to 100% of patients (Table  1). Accordingly, secondary infer - tility due to the niche was resolved in 50% to 100% of the population studied [15– 17, 19–28, 30, 32] (Table  1). Fur- thermore, no intraoperative severe complications such as uterine perforation or bladder injury from the resectoscopic resection were reported by neither of all authors (Table  1). Most authors acknowledge that low residual myome- trial thickness (RMT) can limit the feasibility of hystero- scopic resection. Although the precise cut-off value remains debated, most studies include patients with an RMT of at least 2 mm to minimize the risks of uterine perforation and bladder injury. Laparoscopic repair Compared to hysteroscopic resection, laparoscopic repair enables complete excision of the cesarian-induced diver - ticulum and fibroid tissue, followed by one-layer or double- layer suturing of the remaining myometrium. Therefore, the laparoscopic approach not only alleviates symptoms associ- ated with the niche, but also increases the RMT. Indeed, a recent prospective cohort study indicated that median RMT increased from 1.0 mm to 6.2 mm in patients undergoing laparoscopic repair of the ceasarian scar defect [33]. Other research groups reported even higher post-laparoscopic RMT measurements of around 10.0 mm [5 , 21]. Therefore, most authors consider laparoscopic repair of the uterine niche in symptomatic patients with RMT ≤ 2.5–3 mm. Regarding the procedure, after pneumoperitoneum induc- tion, adhesiolysis between the bladder and the CSD could be performed, if adhesions are present. To avoid bladder injury, the visceral peritoneum above the anterior uterine wall is opened with a direction laterally to centrally, so blad- der injury could be avoided. Then, the complete CSD could be revealed and following bladder dissection, complete resection of the CSD could be performed. As mentioned above, after complete uterine niche resection, suturing of the remaining myometrium could be performed by single layer or double layer sutures. Most researchers opt for double layer suturing of the myometrium[5, 25, 34–38], while oth- ers believe that one layer is enough. This remains a subject of ongoing debate, as no study to date has directly compared the efficacy of the two methods. Additionally, in case of a retroflexed uterus, many practitioners recommend the bilat- eral shortening of the round ligaments at the end of the pro- cedure to minimize wound stretching forces and, therefore, enhance better healing [34, 37]. Overall, after laparoscopic repair, significantly improved symptoms associated with the CSD were reported in 46% to 100% of patients [17, 21, 25, 34, 35, 37–43] (Table  2). Interestingly, in the research group where 46% of patients experienced significant symptom improvement after surgery, overall symptom improvement was observed in 77.4% of cases [25]. This study compared combined laparoscopic and hysteroscopic repair with hysteroscopic repair alone in terms of postmenstrual bleeding relief and pregnancy rates. The combined laparoscopic approach demonstrated slightly better symptom relief, with median postmenstrual bleeding durations of 8 days compared to 9 days for the hysteroscopic approach (p < 0.05 for both). However, no statistically signif- icant differences in pregnancy rates were observed between the two methods. [25]. Regarding secondary infertility improvement, Karampe- las et al. [42]reported an 83.3% improvement rate. In con- trast, Tanimura et al. [ 21] and Donnez et al. [ 34]reported improvement rates of 55.6% and 44%, respectively. Addi- tionally, another study—whose details regarding the inclu- sion of infertile women are unclear—reported that 31% of women became pregnant within a maximum follow-up period of four years after surgery [36]. CSD recurrence was infrequent across the studies reviewed. Specifically, Nirgianakis et al. [40] reported a recurrence rate of 4.7%, while Zhang et al. [39] and Vervoort et al. [37] reported rates of 16% and 11.9%, respectively. Finally, intraoperative and postoperative complication rates were generally low across the studies reviewed. Nota- bly, only Vervoort et al. reported intraoperative complica- tions, including 2 cases of muscular bladder laceration, 2 instances of vessel injury, and 1 case of uterine perforation [37]. Robotic‑assisted repair Overall, four studies were identified reporting on robotic- assisted repair of CSD with [44, 45] or without [46, 47] simultaneous cesarean scar (CS) pregnancy management. Baseline characteristics and surgical outcomes are reported in Table  3. In 2009, Persson et al. described in a case-report the first robot-assisted Cesarean Scar (CS) ectopic pregnancy 16 Archives of Gynecology and Obstetrics (2025) 311:13–24 Table 1 Hysteroscopic repair: study characteristics and surgical outcomes Author, Year Location Sample size Age [mean ± SD] No. of CS [mean ± SD] Surgical outcomes Intra and postoperative complications, postopera- tive hospital stay (hours, mean ± SD) Fernandez et al., 1996 [20] Santiago, Chile 7 N/A N/A Resolution of PAUB, secondary infertil- ity treated in 50% of patients No complications reported, N/A Fabres et al., 2003 [22] Santiago, Chile 32 N/A N/A N/A No complications reported, N/A Gubbini et al., 2008 [23] Bologna, Italy 26 29–42 1–3 100% CSD treated, resolution of PAUB in 100% of patients, secondary infertility treated in 77,8% of patients [7/9] No complications reported, N/A Chang et al., 2009 [28] Taiwan 22 32.13 ± 4.86 1.82 ± 0.66 PAUB resolution in 64% of patients [14/22] No complications occurred, N/A Gubbini et al., 2011 [19] Italy 41 35,0 ± 4,1 1–3 Resolution of PAUB and suprapubic pain in 100% of patients, Secondary infertility treated in 100% of patients No complications reported, N/A Wang et al., 2011 [30] Taiwan 57 37.8 ± 5.6 2,1 ± 0,8 Improvement of symptoms in 59,6% of patients No complications occurred, N/A Feng et al., 2012 [27] China 57 34 ± 5,4 1,1 ± 0,8 PAUB resolution in 66,7% of patients, PAUB improvement in 35,1%, dysmenorrhea resolution in 12%, dys- menorrhea alleviation in 26,3% No complications occurred, N/A Li et al., 2014 [17] Beijing, China 24 34,8 ± 4,0 75% 1 CS 25% 2 CS Improved PAUB No complications occurred, 24 h Raimondo et al., 2015 [26] Bologna, Italy 120 39,2 ± 4,51 N/A CSD treated 100% of patients, PAUB and pelvic pain resolution in 80%, symptoms improved in 7% No complications occurred, N/A Tanimura et al., 2015 [21] Toyama, Japan 4 37,0 N/A Secondary infertility treated in 100% of patients No complications occurred, N/A Muzii et al., 2017 [15 Rome, Italy 23 39,7 ± 4,0 34% 1 CS 48% 2 CS 18% > 3 CS Shorter PAUB duration, secondary infertility treated No complications occurred, N/A Tsuji et al., 2017 [16] Shiga, Japan 18 34,8 N/A Secondary infertility treated in 40% of patients [4/10] No complications occurred, N/A Vervoort et al., 2017 [24] Denmark 52 36,6 ± 5,0 1 Improved PAUB, improved quality of life, sexual function No complications occurred, N/A Lv et al., 2018 [25] China 47 31,8 1,2 Significant improve- ment of menstruation duration in 23,4%, improvement in 46,8% No complications occurred, N/A 17Archives of Gynecology and Obstetrics (2025) 311:13–24 management and the same technique was followed by later researchers to repair the uterine diverticulum [44]. The researchers used a four-arm Da Vinci approach and two 12-mm assistant trocars. Following pelvic dissection, metal clips were applied to distal internal iliac arteries and the propria ligaments. Then, the myometrium around the defect was excised using single 2–0 Vicryl sutures [48]. Hoffmann et al. employed three Da Vinci trocars along with a 12 mm assistant trocar. Enhanced visualization of vascularized tis- sue was achieved through the periodic intravenous use of indocyanine green injection and the robotic firefly feature [45]. Similarly, three arm da Vinci plus one 10 mm assistant trocar was applied by Cardaillac et al. [47]. Hofgaard et al. reported the Da Vinci surgical CS preg- nancy management simultaneous with CSD repair of 14 patients. The researchers reported no perioperative com- plications. However, postoperatively, they noted three Cla- vien-Dindo II complications and one Clavien-Dindo IIIa complication, specifically recurrent minor vaginal bleeding attributed to isthmic synechiae [44]. Wang et al. performed three robot-assisted isthmocele repairs with no postopera- tive complications reported, albeit one bladder perforation was noted intraoperatively during adhesiolysis [46]. In a case series involving five patients, Hoffmann et al. reported successful cesarean scar pregnancy removal combined with uterine defect repair. There were no perioperative or postop- erative complications, and no recurrence of the defect was observed [45]. In a two-center retrospective study conducted by Cardaillac et al. in 2022, 33 isthmoceles were surgically repaired using the Da Vinci robotic platform. During the study, one case required conversion to laparotomy due to a vessel injury. Additionally, two patients developed pel- vic pain postoperatively and needed to visit the emergency department. Of these, one required a subsequent reoperation through laparotomy [47]. Among the studies, Hofgaard et al. [44] reported a 64% pregnancy rate following the procedure, while Cardaillac et al. [47] and Hoffmann et al. [45] reported subsequent pregnancy rates of 75% and 40%, respectively. However, the study of Hoffmann et al. did not clarify whether the follow- up period was sufficient for additional pregnancies to occur or whether all participants desired a subsequent pregnancy [45]. Furthermore, as indicated in Table 3, length of hospital stay is relatively low with the robotic approach. Vaginal repair The vaginal approach offers another well-established approach for repairing a CSD. The vesicovaginal space through the cervicovaginal junction must be opened and the bladder must be stripped to expose the anterior uterine wall. The defect may be closed using either one layer [49] or double layer sutures [38, 39, 50–53], albeit the superior- ity of one method to another is still a subject of debate. The characteristics and surgical outcomes of each study included in this surgical subgroup are presented in Table  4. Overall, symptom relief—such as alleviation of abnormal uterine bleeding or postmenstrual spotting—was achieved in 57–92.9% of patients, according to the studies reviewed [38, 39, 49–53] (Table  4). Collectively, no postoperative compli- cations were reported across the studies. Intraoperatively, Luo et al. [50] reported a single case of infection, Chen et al. [52] noted three hematomas and two bladder injuries, while Deng et al. [51] documented three bladder injuries and one hematoma. These findings suggest that the overall rate of intraoperative complications in the vaginal repair group is relatively low, especially considering the large number of patients included in each study. Regarding CSD recurrence, studies reported percent- ages ranging from 7.1 to 42.6%, suggesting a relatively high recurrence rate (Table  4). Furthermore, the length of hospital stay is generally longer for vaginal repair (Table  4) compared to other minimally invasive procedures, such as laparoscopic or robotic repair of the defect. Table 1 (continued) Author, Year Location Sample size Age [mean ± SD] No. of CS [mean ± SD] Surgical outcomes Intra and postoperative complications, postopera- tive hospital stay (hours, mean ± SD) Shapira et al., 2020 [32] Tel-Aviv, Israel 67 38,0 ± 5,5 24% 1 CS 76% > 1 CS PAUB treated in 63,4% of patients, secondary infertility treated in 52,6% of patients No complications occurred, N/A Casadio et al., 2021 [31] Italy 309 36 + 4.3 1–2 Uterine bleeding controlled in 97.1%, Pelvic pain controlled in 92.6% Cervical laceration 1.9%, Pain requiring hospital stay > 4 h 1.9%, Nausea 1.9%, Hospital stay: 3.68 ± 3.21 BMI body mass index, CS Caesarian Sectio, N/A not applicable 18 Archives of Gynecology and Obstetrics (2025) 311:13–24 Table 2 Laparoscopic repair: study characteristics and surgical outcomes Author, Year Location Sample size Age [mean ± SD] [patients receiving treatment] No. of CS [mean ± SD] Surgical outcomes Intra& Postop- erative Complica- tions, Postopera- tive hospital stay (days, mean ± SD) CSD recurrence Marotta et al., 2013 [36] Belgium 13 28–36 61% 1 CS 31% 2 CS 8% 3 CS Symptoms relief 100%, Improved fertil- ity No complications occurred, 2–3 No recurrence reported Li et al., 2014 [17] China 41 34,8 ± 4,0 75% 1 CS 25% 2 CS Symptoms relief, Caesarean scar defect repair in 100% of patients No complications occurred, N/A No recurrence reported Nirgianakis et al., 2015 [40] Switzerland 21 35 [median] [25–41] 3 Caesarean scar defect repair in 95% of patients No complications occurred, 3 4,7% [1/21] Tanimura et al., 2015 [21] Japan 22 37,0 N/A Secondary infer- tility treated in 55,6% of patients No complications occurred, N/A No recurrence reported Li et al., 2016 [41] China 40 30.7 ± 6.6 65% 1CS Improved men- strual cycles in 92,5% of patients No complications occurred, N/A No recurrence reported Liu et al., 2016 [35] China 49 33,5 ± 5,3 1,3 ± 0,5 Shorter menstrual periods No complications occurred, 4,1 ± 0,3 No recurrence reported Zhang, 2016 [39] China 124 32,0 ± 5,0 80% 1 CS 20% 2 CS Shorter PAUB duration in 86% of patients, Caesarean scar defect repair in 86% of patients No complications occurred, 6,5 ± 2,1 16% [8/59] Zhang et al., 2016 [38] China 86 N/A N/A Improved men- strual cycles No complications occurred, 7,0 ± 2,7 No recurrence reported Donnez et al., 2017 [34] Belgium 38 18–44 66% 1 CS 31% 2 CS 3% 3 CS Symptoms relief in 92% of patients, infertil- ity treated in 44%of patients No complications occurred, N/A No recurrence reported Dosedla et al., 2017 [43] Czech Republik 111 34 [median age] [26–39] 1 [median] 1–3 Shorter PAUB duration No complications occurred, N/A No recurrence reported Vervoort et al., 2017 [37] Netherlands 158 32,8 ± 10,8 1 Shorter PAUB duration, symp- toms slightly improved, improved qual- ity of life No complications occurred, N/A 11,9% [12/101] Lv et al., 2018 [25] China 82 31,2 1,2 46% significantly improved symptoms, 33% improved symptoms, 20% not improved No complications occurred, N/A No recurrence reported 19Archives of Gynecology and Obstetrics (2025) 311:13–24 Regarding obstetric outcomes, Deng et al. reported a 67% pregnancy rate in a cohort of 124 patients who underwent repair using the vaginal approach [51].

The current narrative review indicates that hysteroscopic and laparoscopic management of cesarean scar defects (CSDs) present similar surgical outcomes in terms of symptom relief, with rates ranging from 56,9% to 100%, and 40% to 100%, respectively. Vaginal repair also shows similar results, with a broad range of overall symptom relief, rates varying from 57% to 92.9%. However, it is associated with a longer postoperative hospital stay compared to the other methods (Table  4). Data on robot-assisted repair of an isthmocele is promising, though studies involving larger patient popula- tions are still limited. Hysteroscopic treatment, as expected, was associated with a lower rate of intraoperative and post- operative complications. A 2020 meta-analysis reported conclusions consistent with our findings. The study highlighted that hysteroscopic resection achieved an 85% (75.05–92.76%) rate of symptom relief, while the laparoscopic/robotic approach provided a 92.77% rate of symptom relief, and the vaginal approach resulted in 82.52% symptom relief. Additionally, hyst- eroscopic surgery was associated with the lowest odds of complications, at 0.76% (0.20–1.66%) [54]. However, the data should be interpreted with caution due to variations in diagnostic criteria for evaluating the defect, the scarcity of randomized trials, and differences in how outcome meas- ures were reported. Due to the considerable variability in diagnostic criteria and outcome reporting across studies, our team has chosen to provide a narrative update on the overall management of isthmoceles. In a head-to-head compari - son between the transvaginal and laparoscopic approaches, Zhang et al. reported that both methods achieved comparable Table 2 (continued) Author, Year Location Sample size Age [mean ± SD] [patients receiving treatment] No. of CS [mean ± SD] Surgical outcomes Intra& Postop- erative Complica- tions, Postopera- tive hospital stay (days, mean ± SD) CSD recurrence Karampelas et al., 2021 [42] Belgium 38 48–24 N/A 71.4% Improve- ment of abnor- mal uterine bleeding, 83.3% of chronic pelvic pain and 83.3% treatment of secondary infertility No complications occurred, N/A No recurrence reported BMI body mass index, CS Caesarian Sectio, N/A not applicable Table 3 Robot assisted CSD repair, characteristics and surgical outcomes N/A Not applicable, CS Caesarian Sectio Author, Year Location Sample size Age [median or mean ± SD] No. of CS No. of patients receiving treatment Perioperative complications [%] Postoperative complications Length of Hospital stay [days, mean ± SD] Subsequent pregnancy [%] Hofgaard et al. 2021 [44] Sweden 14 36 [median] 1–3 14 b 3 CD II, 1 CDIII-a 2 9/14 [64] Wang et al. 2021 [46] Taiwan 3 NA 2.0 ± 0.6 3 1/3 [33] No complica- tions 3.6 ± 1 NA Hoffmann et al. 2021 [45] USA 5 35 [Median] 1–3 5 No complica- tions No complica- tions NA 2/5 [40] Cardaillac et al. 2022 [47] France 33 32.6 ± 3.2 1–3 33 1/33 [33] Conversion to open 2/33 [6] 1.7 ± 1 15/20[75] 20 Archives of Gynecology and Obstetrics (2025) 311:13–24 Table 4 Vaginal repair: study characteristics and surgical outcomes N/A Not applicable, CS Caesarian Sectio Author, Year Location Sample size Age [mean ± SD] [patients receiving treat- ment] No. of cesarean deliveries [mean ± SD] Surgical outcomes Intra& Postoperative Complications, Postop- erative hospital stay (days, mean ± SD) CSD Recurrence Luo et al., 2012 [50] China 42 34 [20–40, median] 1 [1–2, median] Symptoms relief in 92,9% of patients infection in 1 patient, 4,0 ± 2,1 7,1% [3/42] Chen et al., 2014 [49] China 64 34,4 N/A Clinical improvement in 85,9% of patients, short- ened menstruation dura- tion in 82,8% of patients, guttate disappearance in 81,8% of patients No complications occurred, 6,0 ± 2,9 N/A Zhang et al., 2016 [38] China 124 31,0 ± 4,0 77% 1CS 23% 2 CS Improved prolonged men- strual bleeding syndrome in 89% of patients, repaired uterine defect in 87% No complications occurred, 4,8 ± 0,3 13% Zhang et al., 2016 [39] China 142 N/A N/A Shortened menstrual periods No complications occurred, 6,4 ± 2,3 N/A Zhou et al., 2018 [53] China 51 31.25 ± 3.36 1.04 ± 0.20 [96% 1 CS 4% > 1 CS] Significant decrease of menstrual duration, CSD disappearance in 68,63% of patients No complications occurred, N/A 31,4% Chen et al., 2018 [52] Shanghai, China 241 Anteflexion group: 33.2 ± 3.7 Retroflexion group: 32.8 ± 3.5 1,3 ± 0,5 Significantly shorter menstruation duration in 80,3% of patients 4 in the anteflexion group: 2 hematomas, 2 bladder injuries [4%], 1 in the retroflexion group: hema- toma [0,7%], 6,0 40% Deng et al., 2021 [51] China 183 34.14 ± 4.44 62% 1 CS 35% 2 CS 3% > 3 CS Complete CSD disap- pearance in 57,14% of patients, improved CSD in 88,95% of patients, significantly shorter men- struation duration [57% of patients], disappearance of pelvic pain in 81,08% of patients, 67% pregnancy rate Bladder injury in 3 patients [1,6%], anterior uterine hematoma in 1 patient [0,5%], 6,08 ± 1,89 42,6% 21Archives of Gynecology and Obstetrics (2025) 311:13–24 surgical outcomes regarding prolonged menstrual bleeding. Specifically, symptom improvement was noted in 89% of patients who underwent the vaginal approach, compared to 85% of those who received the laparoscopic approach. The authors concluded that the vaginal approach may be more cost effective and convenient for a symptomatic patient [39]. Regarding reproductive outcomes, the da Vinci approach showed rates ranging from 40 to 75%, the hysteroscopic resection indicated pregnancy rates in 50% to 100% of patients and the laparoscopic treatment achieved rates from 44 to 83.3%. In the vaginal group, one study reported preg- nancy rates of 67%[51]. A recent systematic review aimed at evaluating fertility outcomes in patients with isthmocele treated surgically reported an overall pregnancy rate of 65.4% across the 13 studies included. However, due to insufficient data, the review could not provide pregnancy rates for each treatment group for more precise comparison. The researchers did note that pregnancy rates were 21 of 28 (75%) for patients treated with hysteroscopy, compared to 9 of 28 (32%) for those who were untreated [55]. These find- ings are based on a robust randomized trial conducted by Abdou et al., which included 56 patients and demonstrated that hysteroscopic remodeling is both effective and low-risk in addressing CSD-induced secondary infertility, provided that the RMT is at least 2.5 mm [56]. Nonetheless, different systematic review and meta-analyses regarding the surgical management of CSDs for secondary infertility prevention reported lack of evidence to support surgical correction of an isthocele to improve fertility outcomes [54, 57]. Surgical intervention may be considered based on specific indica- tions. Clinicians should exercise caution when determin- ing whether CSD is the sole cause of infertility, as care- ful assessment is required to ensure accurate diagnosis and treatment planning. As previously mentioned, hysteroscopy is generally avoided by most authors when the RMT is less than 3 mm [10], as it is often considered more suitable for resection rather than complete repair in such cases. This limitation in patient selection could constitute bias, which is related with the improved reported outcomes for this method. Despite the encouraging success rates for secondary infertility treatment, ranging from 50 to 100%, women with an RMT of less than 3 mm who wish to conceive should typically be excluded from the hysteroscopic approach [58]. The decision to pursue surgery should be based on a comprehensive evaluation of various factors and should be thoroughly discussed with the patient. Key parameters to consider before deciding on the feasibility and type of surgical management include the severity of symptoms, the presence of infertility, the desire for future pregnancies, as well as the size of CSD and RMT. Isthmoceles are associ- ated with postmenstrual spotting, which negatively affects sexuality [59] and increases the use of oral contraceptives [60]. These both can result in decreasing rates of natural conception [3 ]. Furthermore, women with CSD have an increased risk of miscarriage in subsequent pregnancies [61], increased risk of CS pregnancy and severe bleeding [62], increased risk of placenta-related complications [63, 64] and uterine rupture in the third trimester [65]. The latter increases as RMT decreases post-surgery, with the hystero- scopic approach appearing less effective than laparoscopic or vaginal approaches in achieving optimal postoperative RMT results. Indeed, Rozenberg et al. reported no cases of uterine rupture or dehiscence when the postoperative RMT was above 4.5 mm in patients with a history of cesarean section [66]. Considering all the factors discussed, a patient with an asymptomatic CSD who does not wish to conceive may be managed with regular follow-up rather than undergoing sur- gery. Pharmacological treatment may be the initial option for symptomatic patients, although medical treatment options have been relatively underexplored. Tahara et al. reported on the effectiveness of oral contraceptives in a series of 11 patients with PAUB. After 3 to 6 cycles, symptoms resolved in all patients [11]. Furthermore, at the 6 month follow-up, 78.4% (80/102) of the women in the levonorgestrel-releas- ing intrauterine device (LNG-IUS) group showed a 50% decrease in spotting, according to a recent RCT. Signifi- cant reductions in spotting were observed in the LNG-IUS group as compared to the hysteroscopic remodeling group, with reductions of 90.2% versus 70.2% (RR: 1.29; 95% CI 1.12–1.48) at 12 months and 89.2% versus 72.1% (RR: 1.24; 95% CI 1.08–1.42) at 9 months [12]. These results imply that pharmacological treatment may be a reasonable first choice for symptomatic patients; nevertheless, more study is urgently required to corroborate these findings. Depend- ing on the severity of symptoms, surgical therapy may be considered for symptomatic patients. The choice of surgical approach should be determined by various patient charac- teristics, with RMT being a key factor. Women with less than 3 mm could not be offered a hysteroscopy as analyzed above. The decision between transvaginal, conventional lap- aroscopy, or robotic approaches can then be guided by the surgeon's experience and the patient’s preferences. Lastly, patients with CSD who wish to conceive may be considered for surgical repair of the defect due to the potential for severe complications. However, it is essential to thoroughly inves- tigate and address other potential causes of infertility prior to proceeding with surgery. Our study has several limitations. First, we opted for a narrative review of the existing literature to analyze surgical

for isthmocele repair, which may introduce some subjectivity due to the influence of the authors' opinions. This approach was chosen because of the considerable vari- ability in diagnostic criteria, treatment indications, and out- come measures reported in the original studies. Second, we 22 Archives of Gynecology and Obstetrics (2025) 311:13–24 did not conduct a risk of bias assessment for the included studies, as this is typically the focus of systematic reviews and meta-analyses. The strength of our study lies in its comprehensive search and analysis of the literature, further enhanced by a critical evaluation of the available evidence.

The rate of CS is increasing worldwide, leading to a corre- sponding rise in the occurrence of CSD. Many CSDs remain asymptomatic over the years and many women with uterine isthocele do not wish to conceive. In contrast, symptomatic women or those wishing to conceive may be offered surgical treatment for this complex condition. The choice of pro - cedure should be guided by various patient characteristics, particularly the RMT, which may determine whether hyst - eroscopic management is suitable or if alternative surgical

are more appropriate. To advance our understand- ing of the various surgical methods for isthmoceles, robust, multi-arm randomized trials or well-structured large obser - vational studies are essential. These studies should compare the efficacy of different approaches, considering not only symptom relief but also patient satisfaction, cost-effective- ness, and overall long-term benefits. Such research would pave the way for the development of more reliable clinical guidelines. Author contributions Stavridis Konstantinos: conceptualization, data collection and management, manuscript writing. Dimitrios Balafoutas: conceptualization, manuscript writing, review & editing. Nikos Vlahos: conceptualization, review & editing. Ralf Joukhadar: conceptualiza- tion, review & editing. Funding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Data availability Not applicable. Declarations Conflict of interest The authors declare no conflicts of interest related to this study. Ethical approval Not applicable.

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