How to perform standardized sonographic examination of uterine niche in non-pregnant women

Cesarean scar niche: comparison of transvaginal ultrasound findings and uterine tissue samples after hysterectomy

BACKGROUND

The cesarean scar niche, a consequence of incomplete wound healing, can lead to gynecological complications and affect future pregnancies. While internal niches have been well-studied, external and bidirectional niches are also important.

OBJECTIVE

We aimed to conduct a comparative analysis of the prevalence and measurements of different types of niches.

STUDY DESIGN

This cross-sectional study examined 200 patients with prior cesarean delivery undergoing hysterectomy due to abnormal uterine bleeding. It evaluated internal, external, and bidirectional niche prevalence, measurements (height, residual myometrial thickness, and adjacent myometrial thickness), and classification in hysterectomy specimens compared to prehysterectomy transvaginal sonography reports. The secondary outcome was to determine niche presence in uterine tissue samples based on the number of previous cesarean deliveries.

RESULTS

The mean age of the study participants was 48.19 years, with 30% having undergone only one cesarean delivery. Notably, 83.5% had niches detected via sonography, while 91% had niches identified in uterine tissue samples posthysterectomy (P value=.008). Internal niches were common, with significant associations between niche presence and the number of previous cesarean deliveries. 23.3% of patients with one cesarean delivery had internal niches. Additionally, external niches were detected in 4% of hysterectomy samples but not observed in ultrasound reports. Key parameters such as residual myometrium thickness and adjacent myometrial thickness differed notably between ultrasound and tissue samples, highlighting discrepancies in niche detection methods. Residual myometrium thickness ranged from 2.8 to 24 mm (7.68±3.09 mm) in ultrasound reports vs 0 to 25 mm (4.28±2.71 mm) in tissue samples (P<.001). Adjacent myometrial thickness ranged from 6 to 29 mm (17.08±4.53 mm) in ultrasound reports vs 7.5 to 30 mm (16±5.03 mm) in tissue samples (P<.001). This study underscores the importance of accurate niche assessment in patients with prior cesarean delivery.

CONCLUSION

We performed a comparative analysis of niche prevalence and measurements in gross specimens and transvaginal sonography reports. The results highlight the importance of considering external and bidirectional niches, in addition to internal niches. These niches can reduce residual myometrial thickness and increase future pregnancy complications. Furthermore, we demonstrated that niche formation can occur after a single cesarean delivery.

Diagnostic yield of transvaginal ultrasonography versus saline: infused sonohysterography in the evaluation of post-cesarean section uterine niche

BACKGROUND

Caesarean section (CS) defects, also known as niches, refer to the discontinuity in the myometrium at the site of a previous CS. These niches pose a complication in over 50% of CS performed on Egyptian women. The primary method used to diagnose uterine niches is transvaginal ultrasound (TVU). In recent times, the use of TVU with saline- infused sonohysterography (SISH) has significantly improved the detection of uterine niches. Our objective was to assess the diagnostic performance of SISH compared to TVU in diagnosing uterine niches among non-pregnant women with previous cesarean sections (CS), by integrating the findings and demographic features of the participants.

METHODS

For this purpose, we conducted a cross-sectional study involving 60 non-pregnant women with a history of CS but without any known systemic cause. Each participant underwent TVU followed by SISH. We recorded and analyzed the dimensions (depth, length and width) of the niche, as well as the residual myometrial thickness (RMT) adjacent to the niche in both TVU and SISH. Additionally, we collected data on the patients' age and the number of previous CSs.

RESULTS

Our results showed that women with a CS niche detected by SISH had a significantly lower age compared to those detected by TVU. We also found a significant association between the number of previous CSs diagnosed by either TVU or SISH and the rate of CS niche detection, which increased with an increasing number of previous CSs. Furthermore, there was a significant difference in the depth, width, and residual myometrial thickness adjacent to the niche between the two procedures. All niche dimensions were significantly higher among women examined by SISH.

CONCLUSION

Our study confirms that SISH is a superior tool for assessing uterine niches in non-pregnant women with a history of CS compared to TVU. Furthermore, the combined approach of using both SISH and TVU eliminates the need for costly hysteroscopy.

Caesarean section scar: Histological analysis on hysterectomy specimen. A pilot study

INTRODUCTION

In recent years, caesarean section (CS) rate has risen worldwide. Complications associated with CS scars have risen too, such as scar dehiscences and uterine ruptures. Uterine healing is a complex phenomenon still poorly understood. The aim of this study is to carry out a comparative histological analysis of healthy and scarred uterus.

MATERIAL AND METHODS

Women who underwent hysterectomy for benign pathology were included prospectively and divided into two groups: previous CS (group 1) versus control (group 2). Hysterectomy specimen were analyzed histologically and immunohistochemically.

RESULTS

Sixty women were included: 30 women per group. In group 1, only 19 women could be analyzed. Median total thickness at the thinnest site of the scar is significantly thinner (4.34 mm; IQR [2.76-9.45]) than that of adjacent healthy isthmus (12.70 mm; IQR [10.45-14.95]) (p < 0.001). It is also thinner than in group 2 (13.45 mm; IQR [11.03-16.90]) (p < 0.001). Median myometrial thickness within the scar in group 1 was also thinner (1.14 mm; IQR [0.30-2.69]) than that of the adjacent healthy isthmus (8.90 mm; IQR [8.18-10.08]) (p < 0.001) and that in group 2 (10.00 mm; IQR [8.38-13.35]) (p < 0.001). There was a significant increase in fibrosis in the scar (55.01 %; IQR [35.71-63.46]) compared with adjacent tissue (17.41 %; IQR [15.08-24.78]) (p < 0.001) and with healthy uterus (33.91 %; IQR [18.93-46.53]) (p = 0.006).

CONCLUSION

In uterus with previous CS scar, total thickness of the wall and thickness of the myometrium are reduced and proportion of fibrosis is significantly increased. This study shows that the thickness of the wall remains reduced in scarred uterus, even very long after CS. Further studies are currently in progress to understand its pathophysiology within the uterus using animal models.

Barbed vs conventional sutures for cesarean uterine scar defects: a randomized clinical trial

BACKGROUND

The role of barbed sutures in preventing myometrial defects and enhancing postpartum outcomes after cesarean section (C-section) is uncertain.

OBJECTIVE

This study compared clinical and ultrasonographic outcomes of uterine scar defects after C-section with barbed and conventional smooth thread sutures.

STUDY DESIGN

This was a multicenter, parallel-group, randomized, controlled clinical trial. Four obstetrics and gynecology departments across three Japanese healthcare regions were included. The participants were women requiring their first cesarean delivery between May 2020 and March 2023. Of the 1211 participants enrolled, 298 underwent C-section and 253 were followed up until July 2023. Participants with singleton pregnancies were randomly assigned (1:1 ratio) to receive either conventional or spiral thread sutures with a double-layer continuous suture. The study period comprised the time of consent to the 6- to 7-month examination. The primary endpoint was the rate of scar niches >2 mm evaluated using transvaginal ultrasonography at 6 to 7 months after surgery. Additional metrics included the total operative time, suture application time, operative blood loss, number of additional sutures required for hemostasis, maternal surgical complications, postoperative infections, surgeon's years of experience, and individual subscale scores.

RESULTS

All data of the 220 participants (barbed suture group: 110; conventional suture group: 110) were available, thus enabling a full analysis set. A comparison of the barbed and conventional suture groups, respectively, revealed the following: niche length, 2.45±1.65 mm (range: 1.0-6.7) vs 3.79±1.84 mm (range: 1.0-11.0) (P<.001); niche depth, 1.78±1.07 mm (range: 1.0-5.7) vs 2.70±1.34 mm (range: 1.0-7.3) (P<.001); residual myometrial thickness (RMT), 8.46±1.74 mm (range: 4.8-13.0) vs 7.07±2.186 mm (range: 2.2-16.2) (P<.001); and niche width, 1.58±2.73 mm (range: 0.0-14.0) vs 2.88±2.36 mm (range: 0.0-11.0) (P<.001), respectively. The barbed suture group exhibited no defects and an RMT <3 mm. Furthermore, the barbed suture group had a lower rate of uterine niches (29.1%; n=32/110) than the conventional suture group (68.2%; n=75/110). Secondary outcomes showed no significant differences in operative times, maternal surgical complications, or postoperative complications.

CONCLUSION

Double-layer barbed sutures during cesarean delivery may prevent C-section scar defects and postoperative complications. El resumen está disponible en Español al final del artículo.

Emerging data on diagnosis and management of uterine isthmoceles: a rapid review

PURPOSE OF REVIEW

With a rising number of cesarean sections, the prevalence of uterine isthmoceles is increasing. We performed a rapid review to assess the most recent data on the diagnosis and management of uterine isthmoceles over the past 18 months to identify current trends and directions for continued research.

RECENT FINDINGS

A comprehensive search was conducted in PubMed (NLM), Embase (Ovid), CINAHL (EBSCOhost) to find English written articles discussing the diagnosis or management of uterine isthmoceles published in the previous 18 months. Data extraction was performed on one hundred articles that met inclusion criteria.

SUMMARY

This rapid review highlights agreement regarding diagnostic methods, symptoms, and recommended treatment paths for patients with symptomatic uterine niches. However, the diversity in definitions hampers the capacity to formulate detailed conclusions regarding the features of uterine niches and their impact on women's health.

A common problem between gynecology, obstetrics, and reproductive medicine: Cesarean section scar defect

Approximately 60% of patients undergoing Cesarean sections may develop Cesarean Scar Defect (CSD), presenting a significant clinical challenge amidst the increasing Cesarean section rates. This condition, marked by a notch in the anterior uterine wall, has evolved as a notable topic in gynecological research. The multifactorial origins of CSD can be broadly classified into labor-related factors, patients' physical conditions, and surgical quality. However, conflicting influences of certain factors across studies make it challenging to determine effective preventive strategies. Additionally, CSD manifests with diverse symptoms, such as abnormal uterine bleeding, dysmenorrhea, chronic pelvic pain, dyspareunia, secondary infertility, and Cesarean scar pregnancy. Some symptoms are often attributed to other diagnoses, leading to delayed treatment. The quandary of when and how to manage CSD also adds to the complexity. Despite the development of various therapies, clear indications and optimal methods for specific conditions remain elusive. This longstanding challenge has troubled clinicians in both identifying and addressing this iatrogenic disease. Recent studies have yielded some compelling consensuses on various aspects of CSD. This review aims to consolidate the current literature on every facet of CSD. We hope to raise awareness among clinicians about this clinical problem, encouraging more relevant research to unveil the complete picture of CSD.

The effect of uterine closure technique on cesarean scar niche development after multiple cesarean deliveries

OBJECTIVES

To use saline infusion sonohysterography (SIS) to evaluate the effect of uterine closure technique on niche formation after multiple cesarean deliveries (CDs).

METHODS

Patients with at least one prior CD were evaluated for niche via SIS. Subgroups of any number repeat CD (>1 prior), lower-order CD (<4 prior), and higher-order CD (≥4 prior) were analyzed, stratifying by hysterotomy closure technique at last cesarean preceding imaging; techniques included Technique A (endometrium-free double-layer closure) and Technique B (single- or double-layer routine endo-myometrial closure). Niche defects were quantified (depth, length, width, and residual myometrial thickness). The primary outcome was clinically significant niche, defined as depth >2 mm. Statistical analysis was performed using chi-square, ANOVA, t-test, Kruskal-Wallis, and multiple logistic regression, with p-values of <0.05 were statistically significant.

RESULTS

A total of 172 post-cesarean SIS studies were reviewed: 105 after repeat CDs, 131 after lower-order CDs, and 41 after higher-order CDs. Technique A was associated with a shorter interval to imaging and more double-layer closures. Technique B was associated with more clinically significant niches across all subgroups, and these niches were significantly longer and deeper when present. Multiple logistic regression demonstrated a 5.6, 8.1, and 11-fold increased adjusted odds of clinically significant niche following Technique B closure in the repeat CD (p<0.01), lower-order CD (p<0.001), and higher-order CD (p=0.04) groups, respectively.

CONCLUSIONS

While multiple CDs are known to increase risk for niche defects and their sequelae, hysterotomy closure technique may help to reduce niche development and severity.

Value and influencing factors of preoperative MRI evaluation for previous cesarean scar defect associated abnormal uterine bleeding in patients undergoing laparoscopic surgery

OBJECTIVES

As the cesarean section rate increases year by year, the treatment of previous cesarean scar defects (PCSD) poses a significant challenge. This study aims to evaluate the clinical value of preoperative magnetic resonance imaging (MRI) technology and analyze relevant influencing factors for patients with abnormal uterine bleeding (AUB) associated with cesarean scar defects who underwent laparoscopic surgery.

METHODS

A retrospective cohort analysis was performed on women who underwent laparoscopic surgery for PCSD-related AUB at the Department of Gynecology, the Third Xiangya Hospital of Central South University from 2018 to 2022. A total of 57 patients who underwent laparoscopic surgery for the treatment of AUB associated with PCSD were divided into 2 groups based on their postoperative clinical cure status: The clinically-cured group (n=28, 49.1%) and the non-clinically-cured group (n=29, 50.9%). After a postoperative follow-up period of 3 months for all participants, logistic regression analysis was conducted to explore the correlation between the clinical cure rate of AUB associated with cesarean scar defects treated by laparoscopic surgery and various factors. These factors included patient age, clinical symptoms, obstetric history, history of cesarean section, basic clinical information, preoperative MRI parameters, and postoperative menstrual conditions.

RESULTS

There were no significant differences in many aspects, including the patient's age at the time of previous cesarean section, number of pregnancy, time since the previous cesarean section, the uterus position assessed by preoperative T2 signal MRI, defect length, defect width, residual muscle layer thickness, adjacent uterine muscle layer thickness, and distance from the defect to the external cervical os between the 2 groups (all P>0.05). However, the time of onset of AUB symptoms (P=0.036, OR=1.019, 95% CI 1.002 to 1.038) and the depth of the defect on the preoperative MRI (P=0.010, OR=5.793, 95% CI 1.635 to 25.210) were identified as risk factors affecting the clinical cure rate.

CONCLUSIONS

The time of onset of AUB symptoms and the depth of the defect on preoperative MRI are risk factors that influence the clinical cure rate of laparoscopic surgery for the treatment of AUB associated with PCSD, which could be helpful for evaluating the prognosis of disease.

A transvaginal ultrasound-based diagnostic calculator for uterus post-cesarean scar defect

BACKGROUND

A cesarean scar defect (CSD) is incomplete healing of the myometrium at the site of a prior cesarean section (CS), complicating more than half of all cesarean sections. While transvaginal ultrasound (TVU) is the most common modality for diagnosing this defect, hysteroscopy remains the gold standard. We aimed to develop an efficient diagnostic tool for CSD among women with abnormal uterine bleeding (AUB) by integrating TVU findings and participants' demographic features.

METHODS

A single-center cross-sectional study was conducted on 100 premenopausal and non-pregnant women with a history of CS complaining of AUB without a known systemic or structural etiology. Each participant underwent a hysteroscopy followed by a TVU the next day. The defect dimensions in TVU, patients' age, and the number of previous CSs were integrated into a binary logistic regression model to evaluate their predictive ability for a hysteroscopy-confirmed CSD.

RESULTS

Hysteroscopy identified 74 (74%) participants with CSD. The variables age, the number of CSs, defect length, and defect width significantly contributed to the logistic regression model to diagnose CSD with odds ratios of 9.7, 0.7, 2.6, and 1.7, respectively. The developed model exhibited accuracy, sensitivity, and specificity of 88.00%, 91.89%, and 76.92%, respectively. The area under the receiver operating curve was 0.955 (P-value < 0.001).

CONCLUSION

Among non-pregnant women suspected of CSD due to AUB, looking at age, the number of previous CSs, and TVU-based defect width and length can efficiently rule CSD out.

Incidence and ultrasonographic characteristics of cesarean scar niches after uterine closure by double-layer barbed suture: A prospective comparative study

OBJECTIVE

To compare the ultrasonographic features of uterine scars and clinical symptoms after cesarean delivery (CD) using barbed and conventional smooth sutures.

METHODS

This case-control study enrolled women who underwent primary CD at 37 weeks of pregnancy or later. The uterus was closed using either double-layer unidirectional barbed suture or conventional double-layer smooth suture. Ultrasound scans of the uterine scar and evaluations of menstrual patterns were performed at 6, 12, and 24 months after surgery.

RESULTS

In all, 102 patients underwent uterine closure with barbed suture, while 135 patients underwent smooth suture. At 6 months, patients in the barbed group had a lower incidence of uterine niches (20.2% vs 32.6%) that were also shallower in depth (P < 0.001). Lower incidence of niches was also observed in the barbed group at 12 and 24 months (P = 0.043 and 0.048, respectively). At these two follow-up times, the smooth group had a higher number of patients reporting postmenstrual spotting (P < 0.05) and more postmenstrual spotting days per month (P < 0.050).

CONCLUSION

The use of double-layer barbed suture during CD was associated with a lower incidence of scar niches and a more favorable menstrual pattern compared with the use of smooth suture.

Aetiology, risk factors and preventive strategies for niche development: A review

The increase in caesarean sections (CS) has resulted in an increase in women with a uterine niche. The exact aetiology of niche development has yet to be elucidated but is likely multifactorial. This study aimed to give a systematic overview of the available literature on histopathological features, risk factors and results of preventive strategies on niche development to gain more insight into the underlying mechanisms. Based on current published data histopathological findings associated with niche development were necrosis, fibrosis, inflammation, adenomyosis and insufficient approximation. Patient-related risk factors included multiple CS, BMI and smoking. Labour-related factors were CS before onset of labour, extended cervical dilatation, premature rupture of membranes and presenting part of the fetus at CS below the pelvic inlet. Preventive strategies should focus on the optimal level of incision, training of surgeons and full-thickness closure of the myometrium (single or double-layer) using non-locking sutures. Conflicting data exist concerning the effect of endometrial inclusion. Future studies without heterogeneity in population, using standardized performance of the CS after proper training and using standardized niche evaluation with a relevant core outcome set are required to allow meta-analyses and to develop evidence-based preventive strategies. These studies are needed to reduce the prevalence of niches and prevent complications in subsequent pregnancies such as caesarean scar pregnancies.

Effectiveness of laparoscopic niche resection versus expectant management in patients with unexplained infertility and a large uterine caesarean scar defect (uterine niche): protocol for a randomised controlled trial (the LAPRES study)

INTRODUCTION

A uterine niche is a defect at the site of the uterine caesarean scar that is associated with gynaecological symptoms and infertility. Promising results are reported in cohort studies after a laparoscopic niche resection concerning reduction of gynaecological symptoms in relation to baseline and concerning pregnancy outcomes. However, randomised controlled trials to study the effect of a laparoscopic niche resection on reproductive outcomes in infertile women are lacking. This study will answer the question if laparoscopic niche resection in comparison to expectant management improves reproductive outcomes in infertile women with a large uterine niche.

METHODS AND ANALYSIS

The LAPRES study is a randomised, non-blinded, controlled trial, including 200 infertile women with a total follow-up of 2 years. Women with the presence of a large niche in the uterine caesarean scar and unexplained infertility of at least 1 year or failed IVF will be randomly allocated to a laparoscopic niche resection within 6 weeks or to expectant management for at least 9 months. A large niche is defined as a niche with a depth of >50% of the myometrial thickness and a residual myometrium of ≤3 mm on transvaginal ultrasound. Those receiving expectant management will be allowed to receive fertility therapies, including assisted reproductive techniques, if indicated. The primary outcome is time to ongoing pregnancy, defined as a viable intrauterine pregnancy at 12 weeks' gestation. Secondary outcome measures are time to conception leading to a live birth, other pregnancy outcomes, received fertility therapies after randomisation, menstruation characteristics, patient satisfaction, quality of life, additional interventions, and surgical and ultrasound outcomes (intervention group). Questionnaires will be filled out at baseline, 6, 12 and 24 months after randomisation. Ultrasound evaluation will be performed at baseline and at 3 months after surgery.

ETHICS AND DISSEMINATION

The study protocol was approved by the medical ethics committee of the Amsterdam University Medical Centre. (Ref. No. 2017.030). Participants will sign a written informed consent before participation. The results of this study will be submitted to a peer-reviewed journal for publication. TRIAL REGISTRATION NUMBER DUTCH TRIAL REGISTER REF NO NL6350 : http://www.trialregister.nl.