Incidence of Caesarean Scar Defect in Cases of Cesarean Section With and Without Bladder Flap Dissection
Phase: PHASE2
Conditions: CS Scar Defect(Niche) How to Avoid
Sponsor: Alexandria University

 
 
INCIDENCE OF CESAREAN SCAR DEFECT IN CASES OF 
CESAREAN SECTION WITH AND WITHOUT BLADDER 
FLAP DISSECTION  
معدل حدو
ث ندبة الشق القيصري في حاالت الوالدة القيصرية 
 بتشريح و بدون تشريح
 المثانة 
Protocol of a thesis submitted to the 
 خطة بحث
مقدمة 
 إلى 
Faculty of Medicine 
 كلية الطب 
Alexandria University  
 جامعة اإلسكندرية 
Department of Obstetrics and Gynaecology 
 قسم التوليد وأمراض النساء 
In partial fulfillment of the 
  إيفاء جزئيا 
requirements of the degree of 
 لشروط الحصول على درجة 
Master of Obstetrics and Gynaecology 
 الماجستير في التوليد  و أ مراض 
 النساء 
 
 
By 
 من 
 
 
Ahmed Ebrahim Abd ElAziz Ebrahim Elatfy أ حمد ابراهيم عبدالعزيز
إ
براهيم العطفي 
MBBCh, Alex. 
 بكالوريوس الطب والجراحة ، اإلسكندرية 
Resident طبيب مقيم  
Alexandria University Maternity Hospital مستشفى الشاطب
ي 
 الجامع
ي باإل سكندرية 
Department of Obstetrics and Gynaecology قسم 
 التوليد 
 وأمراض 
 النساء 
Faculty of Medicine 
 كلية الطب 
Alexandria University 
 جامعة اإلسكندرية 
2023 ٣٢٠٢ 
 

2. 
 
SUPERVISORS المشرفون 
 
 
Dr. Tamer Ahmed Hosny Labib د/تامر احمد حسني لبيب  
Assistant Professor of Obstetrics and Gynaecology, 
 أستاذ 
 مساعد 
 التوليد أو مراض النساء 
Faculty of Medicine, 
 كلية الطب 
Alexandria University. 
 جامعة اإلسكندرية 
 
 
Dr. Hesham Mahmoud Adel 
 /د
هشام محمود عادل 
Assistant Professor of Obstetrics and Gynaecology, 
 أستاذ مساعد 
 التوليد 
 وأمراض النساء  
Faculty of Medicine, 
 كلية الطب 
Alexandria University. 
 جامعة اإلسكندرية 
 
 
 
 
 

3. 
 
INTRODUCTION 
Anatomically Uterine niche is an iatrogenic pouch-like defect at the site of 
previous caesarean scar due to defective tissue healing. Radiologically niche 
should be defined as an indentation at the site of the CS scar with a depth of at 
least 2 mm. A niche can be subclassified in: (1) simple niche; (2) simple niche 
with one branch; (3) complex niche (with more than one branch). (1-3) 
Uterine niche occurs in up to 70% women with previous cesarean of whom 
30% are symptomatic. Reported prevalence varies: 24–70% with transvaginal 
sonography (TVS) and 56–84% with gel/saline instillation sonohysterography 
(SHG).This may be an underestimation because many women are asymptomatic 
and also because clinicians may not recognize niche as a cause of symptoms due 
to unawareness. Prevalence of 45.6% was reported in a prospective 
observational study (n = 371) where sonohysterography was done six months 
post-cesarean. Prevalence increases with increasing number of previous 
cesareans. (1-5) 
Potential Risk Factors 
Niche forms due to poor healing of cesarean scar. Risk factors are: (5-8) 
1. Factors Affecting Lower Uterine Segment:  
Cervical dilatation of > 5 cm, > 5 h duration of labour and advanced fetal 
station predispose to large niche due to thinner or less vascularized myometrium 
resulting in inadequate healing.(5,6) 
2. Level of Uterine Incision 
Lower uterine incision towards the cervix results in poor healing, as mucus 
secreted by cervical glands interferes with myometrial approximation. Mucus 
accumulation gradually increases the niche size also.(5,7) 

4. 
 
Cesarean section done in advanced labour after cervical effacement and 
also creation of uterovesical fold of peritoneum influence the level of uterine 
incision. 
3. Uterine Closure Techniques 
Single-layer, decidua sparing closure technique predisposes to incomplete 
closure, compared to single full-thickness closure. A strong myometrial scar 
with proper anatomical approximation without tissue strangulation minimizes 
risk of niches. (1,8) 
If muscular edges are thick, they are best approximated by including deeper 
part in the first layer and the remaining superficial cut edges in the second layer. 
Non-perpendicular sutures leading to an irregular myometrial closure, 
locking sutures or very tight second layer leading to ischemic necrosis result in 
poorly healed scar predisposing to niche formation. 
Thus, double-layer uterine closure using non-locking sutures is the optimal 
closure technique that results in thicker residual myometrium and hence 
potentially lower risk of niches. 
Suboptimal surgical techniques: Inadequate haemostasis, tissue ischemia, 
devascularization and excessive tissue manipulation contribute to poor scar 
healing and adhesions, consequently forming niche. 
4. Adhesions 
Adhesion formation with abdominal wall pulls the uterine scar towards 
abdominal wall, exerting counteracting force opposite to the direction of 
retracting uterine scar tissue and causing impaired wound healing. This 
mechanism is encountered in non closure of peritoneum and creation of bladder 
flap that is not sutured. (7) 

5. 
 
5. Retroflexed Uterus 
Effect of gravity on uterine corpus also increases counteracting forces. 
Large niches are mostly found with retroflexed uterus. (6,7) 
6. Patient Factors 
Genetic predisposition contributes to impaired healing, inflammation, or 
adhesion formation, post-operative infection. (7) 
Gestational diabetes (odds ratio, 1.73), previous caesarean (OR, 3.14) and 
advanced body mass index (OR, 1.06) are independent risk factors. Risk 
increases by 6% for every additional unit increase in body mass index. (8) 
Diagnosis: 
Niche can be visualized in non-pregnant state using TVS, SHG, 3-D 
ultrasound, magnetic resonance imaging or hysteroscopy. An anechoic space at 
least 2 mm deep in the myometrium at caesarean scar site clinches the diagnosis. 
Niche Size and Residual Myometrium thickness are measured. 
Residual myometrial thickness (RMT) is the vertical distance between 
uterine serosa and apex of defect. Large niches are defined when RMT is < 50% 
of adjacent myometrium or ≤ 2.2 mm on TVS. Absent residual myometrium is 
termed a total defect. (9) 
 
 

6. 
 
AIM OF THE WORK 
The aim of this study is to compare Incidence of cesarean scar defect in 
cases of cesarean section with and without bladder flap dissection.  
 
 

7. 
 
PATIENTS 
This study will be prospectively conducted on 250 women recruited from 
ElShatby university maternity hospital delivery ward; They will be randomized 
into two groups group (A) and group (B) by closed envelop randomization. 
Group (A) will undergo cesarean section with bladder dissection and group (B) 
will undergo cesarean section without bladder dissection. 
Inclusion Criteria: 
1- Patients who will undergo cesarean section for the first time (primi section) 
Exclusion Criteria: 
1- Patient with excessive adhesion that necessitate bladder dissection 
2- Previous uterine surgery e.g. myomectomy 
3- Patient with comorbidities affecting wound healing e.g. diabetes, 
autoimmune diseases , immunosuppression  
4- Patient in active labour with cervical dilatation > 5cm  
 
 

8. 
 
METHODS 
The patients will be randomized into two groups by closed envelop 
randomization ; group (A) will undergo cesarean section with bladder dissection 
and group (B) will undergo cesarean section without bladder dissection. 
All patients will be subjected to the following: 
1- Complete history taking (gynecological, obstetric, medical, surgical) 
2- Cesarean section using Joel-Cohen incision (10) : 
•  Joel-Cohen skin incision(straight skin incision 3 cm below the line 
connecting the anterior superior iliac spines) 
• Blunt dissection of the subcutaneous layer 
• Blunt extension of the fascial opening 
• Blunt entry into the peritoneum 
• Sharp superficial then blunt entry into the uterus 
• Spontaneous removal of the placenta 
• Double layer closure of the uterus 
• Non-closure of the peritoneum 
• Continuous closure of the fascia 
• Continuous suture of the skin 
Group (A) will be subjected to bladder flap dissection after blunt entry to 
peritoneum and before sharp entry to uterus, while group (B) will undergo 
traditional steps with sharp and blunt entry into uterus directly after blunt entry 
into peritoneum 

9. 
 
After 3 and 6 months all patients will be subjected to Two-dimensional 
trans vaginal ultrasound : 
Women will be examined after emptying their bladder. The uterus and 
uterine scar will be examined in the mid sagittal plane. A niche is defined as an 
anechoic space at least 2 mm deep at the presumed site of the cesarean section 
scar. 
Methods of measurement according to modified Delphi procedure: 
Endometrium should be ignored; niche measurements are based only on 
myometrium. Best method to obtain correct sagittal plane for niche 
measurement is by starting in mid-sagittal plane, with good visualization of 
cervical canal, then moving transvaginal probe laterally to both sides. 
Best method to visualize niche in transverse plane is by starting in sagittal 
plane, keeping good visualization of niche while rotating transvaginal probe 
from sagittal to transverse plane. 
Best method to detect possible branches is in transverse plane, screening 
entire lower uterine segment from cervix to corpus . 
To measure uterine niche, there should be good visualization of lower 
uterine segment only; this applies to all uterine positions (anteversion, 
retroversion or stretched). 
It is useful to vary pressure with transvaginal probe in order to achieve best 
plane for niche measurement. 
For simple niches, all measurements can be done in a single plane, while, 
for complex niches, more than one plane may be necessary . 
The length, depth and width of the niche should each be measured in the 
plane in which it is largest. The distances between the niche and the VV 

10. 
 
fold, and the niche and the external os were considered not to provide additional 
value for basic niche evaluation. 
RMT should be measured in the sagittal plane in which the main niche has 
the smallest RMT.If visible, branches should be measured; measurements of the 
depth and the RMT should be made separately for the main niche and including 
any branch. (11) 
Outcome measures: 
1. Incidence of occurrence of cesarean scar (cs) niche in each group. 
2. Correlation between the depth of niche and the residual myometrium in 
each group. 
3. Comparison between the thicknesses of residual myometrium to adjacent 
normal myometrium in each group. 
4. Complains of niche if present.  
 
 

11. 
 
ETHICS OF RESEARCH 
Research on human or human products: 
 
Prospective study: Informed consent will be taken from patients. In case of 
incompetent patients, the informed consent will be taken from the 
guardians. 
 
Retrospective study: Confidentiality of records will be considered. 
 
DNA / genomic material: Informed consent for DNA / genomic test and for 
research will be taken from patients. No further tests will be carried out 
except with further approval of committee and patients. If the samples will 
travel outside Egypt the researcher will be responsible for transportation 
and security approval. 
 
All drugs used in the research are approved by the Egyptian Ministry of 
Health. 
 
Research on animal: 
 
The animal species are appropriate for the test. 
 
After test, if the animal will suffer, it will be euthanized and properly disposed. 
 
After operation, it will have a proper postoperative care. 
 
 
 سأقوم بتسليم الموافقات المبنية على علم المريض الخاصة بالدراسة عند االنتهاء منها أو
 عند طلبها من اللجنة 
 

12. 
 
RESULTS 
The results will be tabulated and statistically analyzed, using the standard 
statistical methods. 
 
 

13. 
 
DISCUSSION 
The results will be discussed in view of achievement of the aim and will be 
compared with available literature and published data. 
 
 

14. 
 
REFERENCES 
1. 
Bij de Vaate AJ, Brolmann HA, van der Voet LF, van der Slikke JW, 
Veersema S, Huirne JA, et al. Ultrasound evaluation of the cesarean scar: 
relation between a niche and postmenstrual spotting. Ultrasound Obstet 
Gynecol 2011;37:93–9.  
2. 
Naji O, Abdallah Y, Bij De Vaate AJ, Smith A, Pexsters A, Stalder C, , et 
el. Standardized approach for imaging and measuring Cesarean section 
scars using ultrasonography. Ultrasound Obstet Gynecol 2012;39:252–9. 
3. 
Van der Voet LF, Bij de Vaate AM, Veersema S, Brölmann HA, Huirne 
JA. Long-term complications of caesarean section. The niche in the scar: a 
prospective cohort study on niche prevalence and its relation to abnormal 
uterine bleeding. BJOG 2014;121(2):236–44. 
4. 
Setubal A, Alves J, Osório F, Guerra A, Fernandes R, Albornoz J, et al. 
Treatment for uterine isthmocele, a pouchlike defect at the site of a 
cesarean section scar. J Minim Invasive Gynecol  2018;25(1):38–46.  
5. 
Vikhareva Osser O, Jokubkiene L, Valentin L. Cesarean section scar 
defects: agreement between transvaginal sonographic findings with and 
without 
saline 
contrast 
enhancement. Ultrasound 
Obstet 
Gynecol 
2010;35:75–83. 
6. 
Bij de Vaate AJ, van der Voet LF, Naji O, Witmer M, Veersema S, 
Brölmann HA, et al. Prevalence, potential risk factors for development and 
symptoms related to the presence of uterine niches following Cesarean 
section: systematic review. Ultrasound Obstet Gynecol 2014;43(4):372–
82.  
 
 

15. 
 
7. 
Vervoort AJ, Uittenbogaard LB, Hehenkamp WJ, Brölmann HA, Mol BW, 
Huirne JA. Why do niches develop in cesarean uterine scars? Hypotheses 
on the aetiology of niche development. Hum Reprod 2015;30(12):2695–
702. 
8. 
Iannone P, Nencini G, Bonaccorsi G, Martinello R, Pontrelli G, Scioscia 
M, et al. Isthmocele: from risk factors to management. Rev Bras Ginecol 
Obstet 2019;41(1):44–52. 
9. 
Antila-Långsjö RM, Mäenpää JU, Huhtala HS, Tomás EI, Staff SM. 
Cesarean scar defect: a prospective study on risk factors. Am J Obstet 
Gynecol 2018;219(5):458. 
10. Ferrari AG, Frigerio LG, Candotti G, Buscaglia M, Petrone M, Taglioretti 
A, et al. Can Joel‐Cohen incision and single layer reconstruction reduce 
cesarean section morbidity? Int J Gynaecol Obstet 2001;72(2):135–43 
11. Jordans IPM, de Leeuw RA, Stegwee SI, Amso NN, Barri-Soldevila PN, 
van den Bosch T, et al. Sonographic examination of uterine niche in non-
pregnant women: a modified Delphi procedure. Ultrasound Obstet 
Gynecol 2019;53(1):107-15.