Barbed Double-Needle Suture for Cesarean Section Uterine Incision Closure: Postoperative Pain and 12-Month Scar Outcomes

Abstract

Background

The optimal suture technique for uterine incision closure during cesarean section remains debated due to concerns regarding long-term scar healing. This study aimed to compare postoperative pain and scar outcomes between barbed double-needle sutures (BDNS) and traditional sutures (TS).

Methods

This retrospective cohort study included women undergoing elective term cesarean delivery from September 2022 to September 2024, grouped by uterine closure suture type. Assessed parameters included uterine closure time, blood loss, postoperative visual analog scale pain scores, analgesic use, time to first flatus and ambulation, hospital stay, 12-month sonographic residual myometrial thickness and niche incidence, and long‑term pelvic symptoms.

Results

Overall, 236 patients were analyzed (TS group, 124; BDNS group, 112). BDNS group demonstrated significantly shorter uterine closure time (3.85±0.72 vs 4.76±1.34 min, P<0.001) and reduced blood loss (285.52±54.18 vs 302.45±68.32 mL, P=0.035). Postoperative resting and activity pain scores were lower (P<0.05), with decreased analgesic requirements (P=0.024). At 12-months, residual myometrial thickness was greater (6.25±1.28 vs 5.82±1.15 mm, P=0.008), niche incidence lower (10.71% vs 24.19%, P=0.007). At 12-months postoperatively, the BDNS group showed significant improvements in SF‑36 bodily pain (P<0.001) and physical function (P=0.014) scores, while chronic pelvic pain and deep dyspareunia (P>0.05) rates did not differ significantly between groups.

Conclusion

Barbed double-needle suture closure for cesarean section is associated with improved intraoperative efficiency, reduced postoperative pain, and better uterine scar morphology compared with traditional smooth suture closure.

Introduction

Cesarean section (CS) is one of the most common abdominal surgeries clinically, but the optimal technique for uterine incision closure remains a topic of ongoing debate due to long-term gynecological sequelae.^1,2 Impaired uterine scar healing can clinically manifest as uterine niche formation, abnormal uterine bleeding, and chronic pelvic pain, significantly affecting postpartum quality of life.^3,4 Advances in surgical techniques and suture materials aim to enhance myometrial recovery and hemostasis, but traditional smooth sutures have limitations, including uneven tension distribution, potential tissue strangulation, and prolonged surgical time.^5,6 Recently introduced barbed sutures offer a promising alternative, providing tissue anchoring without the need for knots.⁷

The process of uterine wound healing is a complex biological cascade involving acute inflammation, angiogenesis, and extracellular matrix remodeling.⁸ Emerging evidence suggests that the mechanical properties of suture materials may modulate the local tissue microenvironment, potentially influencing signaling pathways associated with fibrosis and collagen deposition.⁹ Excessive tension at the suture line or local ischemia due to traditional interrupted or continuous locking sutures are common issues that may predispose patients to defects in myometrial repair and subsequent niche development.¹⁰

In contrast, barbed sutures may distribute tension more evenly along the incision line, thereby reducing the risk of compromised microcirculation and promoting a more favorable anatomical repair of the lower uterine segment.¹¹ This even distribution of tension can help mitigate the risks associated with excessive tissue tension and ischemia, which are often seen with traditional smooth sutures.¹² Consequently, barbed sutures could offer improved outcomes in terms of both short-term recovery and long-term scar quality, potentially leading to better postpartum health and quality of life for patients.¹³

Despite theoretical advantages, current literature has three critical gaps that preclude definitive recommendations. Most studies report only short-term outcomes, lacking 12‑month objective scar morphology such as residual thickness and diverticulum dimensions.^14,15 Few integrate pain trajectories, ultrasound healing parameters, and quality of life in a unified analysis. Asian evidence is scarce, so generalizability from Western cohorts to Chinese women remains uncertain. To address these gaps, we conducted a retrospective cohort study with 12‑month ultrasound follow‑up to compare BDNS and TS for CS uterine closure. We hypothesized that, compared with TS, BDNS would be associated with superior 12‑month uterine scar morphology (greater residual myometrial thickness and lower niche incidence) and reduced postoperative pain, without increasing intraoperative complications or compromising safety outcomes. Our novel contribution is the integrated assessment of short‑term surgical performance and long‑term scar healing and quality of life, providing evidence to guide suture selection in Chinese obstetric practice.

Methods

Study Design and Ethics Statement

This study is a retrospective cohort study. Retrospective analysis was performed on the anonymized medical records of 236 parturients who underwent elective cesarean section at our hospital from September 2022 to September 2024, including 112 cases in the barbed double-needle suture (BDNS) group and 124 cases in the traditional suture (TS) group. The primary aim of this study is to compare the differences in postoperative pain and long-term scar healing between using barbed double-needle sutures versus traditional smooth sutures for uterine incision closure.

All data were extracted in a de-identified manner from the hospital’s electronic medical record system and the picture archiving and communication system. Given that this study involved a retrospective analysis of existing clinical data, no additional interventions were imposed on patients or influenced their diagnostic and treatment processes. Therefore, after review and approval by the Shijiazhuang People’s Hospital’s ethics committee (Approval No. 2021–006), this study was conducted in accordance with the tenets of the Declaration of Helsinki. The requirement for informed consent was waived.

Inclusion and Exclusion Criteria

Inclusion Criteria: (1) Patients with a singleton pregnancy who underwent elective cesarean section at ≥37 weeks of gestation; (2) Age ≥18 years old; (3) Complete follow-up data.

Exclusion Criteria: (1) Pregnant women <37 weeks of gestation; (2) Twin or multiple pregnancies, macrosomia, placenta previa, placental abruption, uterine fibroids complicating pregnancy, or other conditions likely to lead to uterine atony; (3) Hematologic diseases, or those with a tendency for bleeding and thrombosis; (4) Emergency cesarean section; (5) Incomplete follow-up data.

Surgical Procedure

All patients underwent elective cesarean delivery under combined spinal-epidural anesthesia, which is the routine anesthetic technique for elective cesarean sections at our institution. All participants were given an intravenous infusion of 1 g cefazolin sodium half an hour before the surgery to prevent infection. The surgical procedure involved a transverse lower uterine segment incision for cesarean section, and the uterine incision was closed using a continuous single-layer double-needle suture technique. After fetal delivery, all patients routinely received an injection of 10 U oxytocin injection into the uterine wall and 10 U oxytocin in 500 mL of 0.9% sodium chloride via intravenous infusion.

For the barbed double-needle suture group, the uterine incision was closed using a 48 mm half-round needle with a size 2 double-needle barbed suture (STRATAFIX™ Spiral PDO Knotless Tissue Control Device, SXPD2B405, Ethicon Inc., Somerville, NJ, USA), each segment being 36 cm long. The first layer of suturing began 1 cm lateral to the apex of the uterine incision on the operator’s opposite side (patient’s left side). After pulling the suture until resistance was felt, indicating that the barbs on the opposite side had engaged the tissue, another stitch was placed approximately 1 cm apart. Both ends of the suture were then pulled in opposite directions and secured using a continuous non-locking manner until reaching 1 cm lateral to the apex of the incision on the other side. Then, 2 to 3 additional stitches were made in the reverse direction, leaving 1 cm of suture exposed at the serosal layer as a marker. The second layer of suturing used the other needle of the barbed suture. It started from between the stitches of the first layer on the left side of the uterus and continued in a continuous non-locking manner up to the marker, followed by 2 to 3 more stitches for fixation. Finally, both barbed sutures were cut along the plane of the uterine serosa.

For the traditional suture group, the uterine incision was closed using a 48 mm half-round needle with a 90 cm long size 1 antimicrobial Vicryl suture. The first layer of suturing began with a stitch 0.5 to 1.0 cm lateral to the apex of the uterine incision on the operator’s near side (patient’s right side). Then, continuous suturing was started from 0.5 to 1.0 cm lateral to the apex of the uterine incision on the operator’s opposite side (patient’s left side) and continued until reaching the opposite side where the suture was tied off. The second layer of suturing started between the stitches of the first layer on the operator’s opposite side (patient’s left side), continuously suturing the myometrium and serosa layers until reaching the apex of the incision, where the suture was then tied off and cut.

Both BDNS and TS were routinely available throughout the study period. Before surgery, each patient received a balanced explanation from the attending obstetrician regarding the two suture techniques, including their benefits, risks, and current evidence. The final choice of suture was made through shared decision-making between the patient and the physician, based on the patient’s informed preference after consultation. All participating surgeons had completed standardized training on both techniques and demonstrated equivalent proficiency prior to the study, ensuring that surgeon skill did not confound the comparison.

All cesarean sections were performed by a dedicated obstetric surgical team consisting of six attending surgeons with at least 5 years of experience in cesarean delivery. To minimize inter‑surgeon variability, all participating surgeons completed a structured training program on both suture techniques prior to the study period. The training included didactic sessions, video‑based instruction, and supervised hands‑on practice on surgical models until proficiency was achieved. Throughout the study period, a standardized surgical protocol was followed for all cases, including uniform incision type, uterine incision location, layered closure technique, and perioperative management. Adherence to the protocol was monitored through regular audits of surgical records. All surgeons had equivalent experience with both suture materials, and the distribution of cases among surgeons was balanced between the two groups.

Data Collection

The primary outcome of this study was uterine scar healing at 12-months postoperatively, assessed by two complementary sonographic parameters: (1) residual myometrial thickness (RMT) at the scar site, and (2) the incidence of uterine scar diverticulum (niche). These parameters were selected as the primary outcome because they represent objective, quantifiable measures of long‑term anatomical repair that are directly relevant to subsequent pregnancy outcomes and gynecological health. Secondary outcomes included intraoperative indicators, postoperative pain, early recovery indicators, long‑term pelvic symptoms, and quality of life.

Baseline Characteristics

Baseline data of all eligible patients were retrospectively collected through the hospital’s electronic medical record system. The collected baseline characteristics included age, body mass index (BMI), gestational age at delivery, history of previous cesarean section, fetal presentation, newborn birth weight, and length. Pre-pregnancy obesity was defined as a pre-pregnancy BMI ≥ 28 kg/m².

Intraoperative Indicators

The uterine incision closure time was defined as the interval from the first needle puncturing the myometrium to the completion of the second layer of suturing and cutting of the suture. This time was recorded by the circulating nurse using the operating room timer and entered into the surgical nursing record sheet. The total surgery time was defined as the duration from skin incision to completion of skin closure, which was cross-verified and obtained from the surgical nursing record sheet.

The intraoperative blood loss was estimated by subtracting the volume of irrigation fluid used during the surgery from the total volume of liquid in the suction bottle, combined with the weight of the gauze used. This estimation was recorded on the anesthesia record sheet. Additional hemostatic sutures were defined as single or figure-of-eight sutures performed outside the double-layer continuous suturing due to persistent oozing or active bleeding from the incision. These additional hemostatic procedures were determined based on descriptions in the surgical records and the surgical nursing record sheets.

Postoperative Pain and Analgesia Assessment

Postoperative pain assessment was conducted using the Visual Analog Scale (VAS).¹⁶ Ward nurses evaluated patients at three specific time points: 12 hours postoperatively at rest, 24 hours postoperatively at rest, and 24 hours postoperatively during activity (defined as turning over in bed or getting out of bed). Patients were uniformly instructed that a score of 0 represented no pain, while a score of 10 represented the most severe pain.

All patients routinely received a patient-controlled intravenous analgesia (PCIA) pump containing sufentanil 50 μg, oxycodone hydrochloride injection 10 mg, plus 0.9% sodium chloride injection to a total volume of 100 mL. The background infusion rate was set at 2 mL/h, with a single bolus dose of 0.5 mL and a lockout time of 15 minutes.

In addition to the routine PCIA pump, patients who reported intolerable pain (VAS ≥ 4) despite using the bolus function received a rescue analgesic of intravenous flurbiprofen axetil 50 mg or tramadol 100 mg, at the discretion of the attending physician, with a minimum interval of 6 hours between additional doses. The number of such rescue analgesic administrations was recorded from ward nursing records and temporary medical orders. All VAS assessments were performed at the designated time points regardless of whether the patient had recently used the PCIA bolus, reflecting the actual analgesic status under the ongoing background infusion.

Early Postoperative Recovery Indicators

The time to first flatus was defined as the interval from the end of surgery to the patient’s first report of passing gas, as recorded by the ward nurse based on patient reports in the nursing record sheet. The time to first ambulation was defined as the interval from the end of surgery to the patient’s first instance of standing or walking with assistance, as documented in the nursing records. Postoperative hospital stay duration was calculated as the cumulative number of days from the day of surgery until the discharge order was issued. Poor wound healing was defined as any abnormal condition of the abdominal incision, including redness, swelling, exudate, fat liquefaction, dehiscence, or infection. This was assessed daily by the attending physician during rounds and recorded in the progress notes. Postoperative fever was defined as an axillary temperature ≥38°C measured at any point from 24 hours postoperatively until discharge, as documented on the nursing temperature chart.

Uterine Scar Ultrasound Assessment

All patients returned to the hospital for a transvaginal ultrasound examination 12-months postoperatively. The ultrasound assessment was performed using a GE Voluson E10 diagnostic ultrasound system with a vaginal probe frequency of 5–9 MHz. Patients were asked to empty their bladder and assume the lithotomy position. The probe was placed in the anterior fornix of the vagina, and images were frozen once the lower segment of the uterus and the scar area were clearly visualized.

The residual myometrial thickness was defined as the vertical distance of the thinnest part of the myometrium between the serosal layer and the endometrial layer at the scar site. The total scar thickness was defined as the full vertical distance from the serosal layer to the endocavitary surface at the scar site. The healing ratio was calculated as the residual myometrial thickness divided by the total scar thickness. Each parameter was measured three times, and the average value was recorded.

The diagnosis of a uterine scar diverticulum was based on the following criteria: discontinuity of the myometrial layer at the lower segment cesarean section incision site, presence of a fluid-filled hypoechoic area communicating with the uterine cavity, and a hypoechoic area depth of ≥2 mm.¹⁷ The diverticulum depth was defined as the vertical distance from the tip of the diverticulum to the line connecting to the uterine serosal layer. The diverticulum width was defined as the maximum anteroposterior diameter of the diverticulum communicating with the uterine cavity on the sagittal plane of the uterus. For patients with a diverticulum, these two parameters were measured three times by the same ultrasound technician on frozen images, and the average value was recorded.

All ultrasound examinations were performed by a single experienced sonographer who was blinded to patients’ clinical data and suture technique allocation. Intra‑observer reliability was assessed by measuring each parameter three times on frozen images, with intraclass correlation coefficients (ICC) > 0.85 for all parameters. Inter‑observer reliability was not formally assessed, as all examinations and measurements were performed by the same sonographer.

Long-Term Pelvic Symptoms Follow-up

At 12-months postoperatively, all patients were followed up via telephone or outpatient review. Chronic pelvic pain was defined as non-cyclic lower abdominal or pelvic pain lasting for at least 6 months, consistent with the American College of Obstetricians and Gynecologists (ACOG) definition of chronic pelvic pain.¹⁸ Abnormal uterine bleeding was defined according to the International Federation of Gynecology and Obstetrics (FIGO) PALM‑COEIN classification system, encompassing any bleeding from the uterine corpus that is abnormal in regularity, volume, frequency, or duration, including intermenstrual bleeding, heavy menstrual bleeding (excessive menstrual blood loss interfering with quality of life), and postcoital bleeding occurring after the cesarean section.¹⁹ Deep dyspareunia was defined as pain during deep vaginal penetration persisting for at least 6 months postoperatively, as per standard gynecological criteria.²⁰

Quality of Life Assessment

At the 12‑month follow‑up postoperatively, quality of life was assessed using the Short Form Health Survey (SF‑36).²¹ The Chinese version of the SF‑36 has been validated in Chinese populations with demonstrated good reliability and validity. Specifically, internal consistency reliability (Cronbach’s α) ranged from 0.72 to 0.88 for six of the eight dimensions. For each of the eight dimensions (physical functioning, role‑physical, bodily pain, general health, vitality, social functioning, role‑emotional, and mental health), raw scores were calculated by summing item scores after reverse‑coding specified items according to the standard SF‑36 scoring manual, and then transformed to a 0–100 scale using the formula: Transformed Score = [(Actual Raw Score − Lowest Possible Raw Score)/Possible Raw Score Range] × 100. Higher scores indicate better quality of life. The eight dimension scores can also be summarized into physical and mental component summary scores. Based on published MCID estimates for the SF‑36 in surgical populations (approximately 3–6 points for physical domains), the observed differences between groups were considered clinically meaningful.

Statistical Analysis

All data analyses were performed using R software (version 4.2.0, R Core Team, Vienna, Austria). Continuous variables were first evaluated for normality using the Shapiro–Wilk test before analysis. Normally distributed continuous variables were expressed as mean ± standard deviation (), and comparisons between two groups were conducted using independent samples t-tests. Non-normally distributed continuous variables were expressed as median (25th percentile, 75th percentile), and comparisons between two groups were performed using the Mann–Whitney U-test. Categorical variables were expressed as frequencies (percentages), and group comparisons were conducted using Pearson’s χ² test. When expected frequencies were less than 5, Fisher’s exact test was used. All tests were two-tailed, and a P-value of <0.05 was considered statistically significant.

No prospective sample size calculation was performed given the retrospective nature of this study. Post‑hoc power analysis was conducted based on the observed data using a two‑sided α of 0.05. For the primary outcome of residual myometrial thickness, the achieved power was 82.4% with the current sample sizes, and for niche incidence, the achieved power was 89.7%, indicating adequate statistical power to detect the observed differences in the main long‑term scar outcomes.

To account for potential confounding, multivariable linear regression was used for continuous outcomes (uterine closure time, blood loss, total operative time, VAS scores, RMT, and SF‑36 scores), adjusting for age, BMI, gestational age, previous cesarean section, fetal presentation, and neonatal birth weight. Multivariable logistic regression was used for binary outcomes (additional hemostatic sutures and uterine niche incidence) with the same adjustment set. Adjusted β coefficients or odds ratios with 95% confidence intervals are reported alongside P values.

Results

Baseline Characteristics

Baseline demographic and obstetric characteristics were comparable between the TS group and the BDNS group across all assessed parameters (Table 1). No significant differences were observed in age (P=0.362), BMI (P=0.135), gestational age at delivery (P=0.819), incidence of previous cesarean section (P=0.831), neonatal birth weight (P=0.680), infant length (P=0.682), prevalence of prepregnancy obesity (P=0.751), or distribution of fetal presentation (P=0.643), or history of previous myomectomy (P=0.929). The distribution of indications for cesarean delivery was also comparable between the two groups (P=0.964). Overall, the two cohorts were well matched with respect to these baseline variables.

Table 1.

Baseline Demographic and Obstetric Characteristics

Variable	TS Group (n=124)	BDNS Group (n=112)	t/χ2	P
Age (years)	29.56 ± 3.12	29.14 ± 3.85	0.914	0.362
BMI (kg/m2)	27.34 ± 2.18	27.78 ± 2.32	1.500	0.135
Gestational age (weeks)	39.04 ± 0.95	39.02 ± 0.98	0.229	0.819
Previous cesarean section history	28 (22.58%)	24 (21.43%)	0.045	0.831
Neonatal birth weight (g)	3355.48 ± 362.25	3375.65 ± 388.69	0.412	0.680
Infant length (cm)	49.39 ± 2.43	49.26 ± 2.55	0.411	0.682
Prepregnancy obesity	23 (18.55%)	19 (16.96%)	0.101	0.751
Fetal position (Head/Breech)	84 (67.74%)/40 (32.26%)	79 (70.54%)/33 (29.46%)	0.215	0.643
Previous myomectomy	2 (1.61%)	1 (0.89%)	0.008	0.929
Indications for CS			0.278	0.964
Previous cesarean section	28 (22.58%)	25 (22.32%)
Fetal malpresentation	40 (32.26%)	33 (29.46%)
Maternal request (social factors)	41 (33.06%)	40 (35.71%)
Other maternal indications	15 (12.10%)	14 (12.50%)

Abbreviation: BMI, body mass index.

Intraoperative Outcomes

Operative efficiency and hemostatic parameters differed significantly between the two suture techniques (Table 2). Uterine incision closure time was notably shorter in the BDNS group than in the TS group (P<0.001). Intraoperative blood loss was lower in the BDNS group relative to the TS group (P=0.035), and total operative time was correspondingly reduced with the use of barbed sutures (P=0.034). Moreover, the requirement for additional hemostatic sutures occurred less frequently in the BDNS group compared to the TS group (P=0.006). Collectively, these findings indicate that the BDNS technique conferred superior intraoperative efficiency and hemostatic control.

Table 2.

Operative Efficiency and Hemostasis

Variable	TS Group (n=124)	BDNS Group (n=112)	Difference (95% CI)	t/χ2	P
Uterine incision closure time (min)	4.76 ± 1.34	3.85 ± 0.72	−0.91 (−1.18, −0.64)	6.580	< 0.001
Intraoperative blood loss (mL)	302.45 ± 68.32	285.52 ± 54.18	−16.93 (−32.71, −1.15)	2.119	0.035
Total operative time (min)	48.64 ± 9.32	46.15 ± 8.45	−2.49 (−4.79, −0.19)	2.137	0.034
Need for additional hemostatic sutures	19 (15.32%)	5 (4.46%)	−10.86% (−17.60%, −4.12%)	7.595	0.006

Postoperative Pain and Early Recovery

Postoperative pain perception and analgesic requirements varied significantly according to the suture method employed (Table 3). Resting VAS scores at 12 hours postoperatively were lower in the BDNS group than in the TS group (P=0.011). Activity VAS scores at 24 hours were likewise reduced in the BDNS group relative to the TS group (P=0.023), and a similar pattern was evident for resting VAS scores at the 24‑hour assessment (P=0.027). In addition, the number of supplementary analgesic doses administered was lower among patients in the BDNS group compared with those in the TS group (P=0.024). These data demonstrate that the BDNS technique was associated with attenuated postoperative discomfort and diminished reliance on rescue analgesia.

Table 3.

Comparison of Postoperative Pain Scores and Analgesic

Variable	TS Group (n=124)	BDNS Group (n=112)	Difference (95% CI)	t/χ2	P
Postoperative 12-hour resting VAS	3.11 ± 0.88	2.84 ± 0.72	−0.27 (−0.48, −0.06)	2.561	0.011
Postoperative 24-hour activity VAS	4.43 ± 1.14	4.12 ± 0.95	−0.31 (−0.58, −0.04)	2.290	0.023
Postoperative 24-hour resting VAS	2.33 ± 0.68	2.15 ± 0.54	−0.18 (−0.34, −0.02)	2.227	0.027
Number of additional doses of analgesic medication (times)				9.440	0.024
0	13 (10.48%)	18 (16.07%)
1	63 (50.81%)	69 (61.61%)
2	41 (33.06%)	24 (21.43%)
3	7 (5.65%)	1 (0.89%)

Early postoperative recovery metrics revealed notable advantages for the barbed suture technique (Table 4). Time to first flatus was shorter in the BDNS group than in the TS group (P=0.007), and time to first out-of-bed activity was similarly reduced among patients in the BDNS group (P<0.001). Postoperative hospital stay was also briefer in the BDNS group relative to the TS group (P=0.001). In contrast, rates of incision healing disorders and postoperative fever did not differ significantly between the two groups (P>0.05). The BDNS approach was associated with accelerated gastrointestinal function recovery and earlier mobilization, culminating in a shortened postoperative hospitalization.

Table 4.

Comparison of Early Postoperative Recovery Indicators

Variable	TS Group (n=124)	BDNS Group (n=112)	t/χ2	P
First flatus time (h)	18.15 ± 5.34	16.45 ± 4.12	2.741	0.007
First out-of-bed activity time (h)	23.06 ± 4.88	21.24 ± 3.25	3.395	< 0.001
Postoperative hospital stay (days)	3.75 ± 0.92	3.42 ± 0.54	3.333	0.001
Incision healing disorders	5 (4.03%)	2 (1.79%)	0.399	0.528
Postoperative fever	3 (2.42%)	3 (2.68%)	0.083	0.774

Uterine Scar Integrity and Niche Formation

Sonographic evaluation of uterine scar integrity revealed measurable differences between the two closure techniques (Figure 1). RMT was greater in the BDNS group than in the TS group (mean difference: 0.43 mm, 95% CI: 0.11, 0.75; P=0.008), and the healing ratio, was correspondingly higher in the BDNS group (mean difference: 0.04, 95% CI: 0.02, 0.06; P<0.001). Total scar thickness did not differ significantly between the groups (mean difference: 0.27 mm, 95% CI: −0.14, 0.68; P=0.196). These findings suggest that the BDNS method yielded a more favorable muscular layer restoration at the uterine incision site.

Figure 1.

Sonographic assessment of uterine scar healing.

Abbreviation: RMT, Residual muscle layer thickness.

The incidence and morphological characteristics of uterine niche formation differed significantly between the two suture groups (Table 5). The diverticulum incidence was lower in the BDNS group than in the TS group (P=0.007). Among those with an identified niche, both diverticulum depth and width were reduced in the BDNS group relative to the TS group (P=0.008 and P=0.006, respectively). These data indicate that barbed suture closure was associated with a diminished frequency of uterine scar defects and, when present, a less pronounced anatomical deformity.

Table 5.

Incidence of Uterine Niche

Variable	TS Group (n=124)	BDNS Group (n=112)	Difference (95% CI)	t/χ2	P
Diverticulum incidence	30 (24.19%)	12 (10.71%)	−13.48% (−23.21%, −3.75%)	7.309	0.007
	(n=30)	(n=12)
Diverticulum depth (mm)	2.89 ± 0.58	2.38 ± 0.31	−0.51 (−0.89, −0.13)	2.871	0.008
Diverticulum width (mm)	5.54 ± 1.52	4.12 ± 1.15	−1.42 (−2.39, −0.45)	2.916	0.006

Long-Term Pelvic Symptoms

Long-term pelvic symptoms assessed at 12-months postoperatively are presented in Figure 2. The incidence of chronic pelvic pain was lower in the BDNS group compared to the TS group, but this difference did not reach statistical significance (P = 0.062). Similarly, the prevalence of deep dyspareunia was comparable between the BDNS group and the TS group, with no significant difference observed (P = 0.581). Both long-term pelvic symptoms showed no statistically significant association with the uterine closure technique.

Figure 2.

Comparison of long-term pelvic symptoms.

Quality of Life

Health-related quality of life scores demonstrated selective improvements in favor of the barbed suture technique (Table 6). PF scores were higher in the BDNS group than in the TS group (P=0.014), and BP scores were notably elevated in the BDNS group relative to the TS group (P<0.001). SF and MH scores did not differ significantly between the two groups (P>0.05). These results indicate that the BDNS closure method was associated with enhanced physical well-being and reduced pain perception in the postoperative period, without discernible effects on social or emotional health domains.

Table 6.

Comparison of Health-Related Quality of Life Scores

Variable	TS Group (n=124)	BDNS Group (n=112)	t	P
PF	87.15 ± 5.68	88.74 ± 4.12	2.472	0.014
BP	79.14 ± 7.82	84.66 ± 6.54	5.843	< 0.001
SF	80.45 ± 9.02	81.12 ± 8.15	0.595	0.553
MH	75.84 ± 8.12	76.56 ± 7.42	0.709	0.479

Abbreviations: PF, physical function; BP, physical pain; SF, social function; MH, mental health.

To account for potential confounding, multivariable linear and logistic regression analyses were performed for the key outcomes, adjusting for age, BMI, gestational age, previous cesarean section, fetal presentation, and neonatal birth weight. In the adjusted models, BDNS remained significantly associated with shorter uterine closure time (adjusted β = −0.88 min, 95% CI: −1.15, −0.61; P<0.001), reduced intraoperative blood loss (adjusted β = −15.82 mL, 95% CI: −31.50, −0.14; P=0.048), and lower 24‑hour activity VAS scores (adjusted β = −0.29, 95% CI: −0.56, −0.02; P=0.035) (Table 7). Regarding uterine scar healing, BDNS was independently associated with greater RMT (adjusted β = 0.41 mm, 95% CI: 0.09, 0.73; P=0.012) and a lower likelihood of uterine niche formation (adjusted OR = 0.38, 95% CI: 0.18, 0.78; P=0.008). For quality‑of‑life outcomes, the beneficial effects of BDNS on SF‑36 bodily pain (adjusted β = 5.38, 95% CI: 3.51, 7.25; P<0.001) and physical function (adjusted β = 1.52, 95% CI: 0.25, 2.79; P=0.019) also remained significant after multivariable adjustment. These adjusted estimates were consistent with the unadjusted findings, confirming the robustness of the observed associations.

Table 7.

Multivariable Regression Analysis for Key Outcomes

Variable	Adjusted β/OR	95% CI	P
Uterine closure time (min)	−0.88	−1.15, −0.61	<0.001
Intraoperative blood loss (mL)	−15.82	−31.50, −0.14	0.048
Total operative time (min)	−2.35	−4.65, −0.05	0.045
Postoperative 12h resting VAS	−0.25	−0.46, −0.04	0.019
Postoperative 24h activity VAS	−0.29	−0.56, −0.02	0.035
RMT (mm)	0.41	0.09, 0.73	0.012
SF-36 Bodily Pain	5.38	3.51, 7.25	<0.001
SF-36 Physical Function	1.52	0.25, 2.79	0.019
Need for additional hemostatic sutures	0.31	0.11, 0.85	0.023
Uterine niche incidence	0.38	0.18, 0.78	0.008

Discussion

This study, through a retrospective cohort analysis, evaluated the outcomes of using barbed double-needle sutures compared to traditional smooth sutures in the closure of uterine incisions during elective cesarean sections. The main findings indicate that the barbed double-needle suture technique offers substantial advantages over traditional smooth suturing methods for cesarean section uterine incision closure. These benefits include enhanced immediate surgical efficiency, improved postoperative recovery, and better long-term gynecological outcomes. The multi-dimensional advantages suggest that barbed suture technology not only helps optimize the immediate surgical experience but also promotes the long-term postpartum health of women undergoing cesarean sections.

The observed increase in intraoperative efficiency in the barbed suture group reflects the fundamental advantages of this suture design. Traditional smooth sutures require surgeons to continuously maintain tension manually and secure it with multiple surgical knots, a process that consumes considerable surgical time and can lead to uneven tissue approximation.²² In contrast, unidirectional barbed sutures anchor securely within the myometrium without the need for knots and are less likely to slip back.²³ This technical advantage directly translates into faster closure times. This finding is consistent with previous reports that have documented time savings with barbed sutures in uterine closure and myomectomy, emphasizing their practical efficiency in reducing anesthesia exposure duration and lowering healthcare resource consumption.²⁴ Additionally, the reduced intraoperative blood loss and lower need for additional hemostatic sutures in the barbed suture group can be attributed to the continuous and uniform tension distributed along the incision line. This mechanism may be due to the ability of barbs to anchor tissue without excessive compression, thereby protecting local microcirculation and preventing ischemia-related complications typically associated with traditional suturing techniques.²⁵

Reducing postoperative pain and the need for analgesia is another clinical advantage of barbed suture technology. The potential mechanism behind this analgesic-saving effect may lie in the avoidance of bulky suture knots and the elimination of focal tension points.²⁶ In traditional closure techniques, the knots themselves can act as foreign body irritants, inducing local myometrial spasms and peritoneal traction. Knotless continuous barbed sutures result in a smoother serosal surface and more physiologically distributed mechanical stress.²⁷ Previous studies have shown that continuous non-locking suture techniques distribute tension more evenly compared to interrupted or locking patterns.²⁸

The accelerated recovery of gastrointestinal function and earlier ambulation observed in this study are reasonable downstream effects of improved pain control. Pain reduction facilitates deeper breathing, early mobilization, and suppression of sympathetic nervous system activation, thereby promoting the return of bowel motility.²⁹ Consequently, the shortened postoperative hospital stay aligns with the principles of enhanced recovery after surgery (ERAS), suggesting that barbed sutures can serve as an effective adjunct in standardized cesarean section rehabilitation protocols.

The long-term integrity of the uterine scar after cesarean section, particularly concerning the formation of a uterine diverticulum which is closely associated with troubling gynecological symptoms, remains a central clinical concern.³ Ultrasound imaging in this study confirmed that barbed suture closure contributes to more robust myometrial healing. The barbed suture group showed better preservation of residual myometrial thickness and higher healing ratios, indicating more optimal repair of muscular structures at the uterine incision site.³⁰ This outcome is likely due to the avoidance of tissue strangulation. Traditional suturing techniques, which use locking stitches or overly tight knots for hemostasis, can impair microvascular perfusion at the incision edges, leading to local tissue necrosis and subsequent replacement with fibrous scar tissue rather than viable myometrium.³¹ Barbed sutures secure tissue without causing strangulation, thereby protecting the fragile blood supply necessary for cell regeneration and collagen deposition.³² The reduced rate of uterine niche formation and smaller defect sizes further support this observation.

Greater residual myometrial thickness is clinically relevant because it reflects better scar integrity. Previous studies have shown that a thinner residual myometrium is associated with an increased risk of uterine rupture in subsequent pregnancies.³³ Although the observed improvement suggests potential benefit for future obstetrical outcomes, prospective studies with extended follow‑up are needed to confirm this relationship.

Previous systematic reviews have highlighted that single-layer locking continuous sutures increase the risk of diverticulum formation compared to double-layer non-locking sutures.³⁴ Barbed suture techniques effectively mimic the benefits of tension-free double-layer closure without the time cost of knotting.³⁵ While the present study did not find significant differences in chronic pelvic pain or deep dyspareunia rates between groups, the more robust anatomical repair observed with barbed sutures could potentially reduce the risk of future niche-related complications. Further studies with larger sample sizes are needed to clarify the relationship between scar morphology and functional pelvic symptoms.

Health-related quality of life scores indicated selective improvements favoring the barbed suture technique, particularly in the domains of physical functioning and bodily pain. This is consistent with the observed advantages of reduced pain and earlier recovery, suggesting that the benefits of this technique extend beyond the immediate postoperative period. There were no differences noted in the domains of social and mental health, which may indicate that these aspects are influenced by broader psychosocial factors beyond surgical technique.

While our findings show clinical benefits of BDNS, practical considerations deserve mention. Barbed sutures are costlier than Vicryl, and formal cost‑effectiveness analyses are needed. Although no barb‑related complications occurred in our cohort, theoretical risks include tissue trauma and suture extrusion. Moreover, product availability varies across institutions, which may limit generalizability.

Several limitations of this study warrant acknowledgment. As a single-center retrospective analysis, the findings may be subject to selection bias and lack the generalizability afforded by multicenter prospective trials. While the retrospective design is suitable for such investigations, it limits the ability to control for all potential confounding variables. The 12-month follow-up provides valuable long-term outcome data, but extended follow-up beyond this period would be necessary to fully describe the durability of the observed benefits and their impact on future pregnancies. Long‑term pelvic symptoms were assessed via retrospective telephone or outpatient recall at 12-months, without a validated pain instrument, which may introduce recall bias. Future prospective studies using validated pain questionnaires at multiple time points are warranted to more accurately characterize these outcomes. In addition, quality of life was assessed only at 12-months postoperatively without a preoperative baseline SF‑36 score, which precludes within‑group longitudinal comparisons. However, the between‑group differences at 12-months remain clinically meaningful as they reflect the differential long‑term impact of the two suture techniques on patients’ physical and pain‑related outcomes. Future studies with baseline and serial postoperative assessments are warranted to further elucidate the trajectory of recovery. Given the exploratory nature of several secondary analyses, we did not adjust for multiple comparisons; therefore, findings in these domains should be interpreted cautiously. The primary outcomes (RMT and niche incidence) were prespecified, and their significance levels remained robust. The comparisons of diverticulum depth and width were limited to the niche‑positive subgroup, with only 12 patients in the BDNS group, which reduces the precision of these estimates; therefore, these findings should be interpreted with caution and require validation in larger cohorts. Some mechanistic interpretations rely on analogical evidence from non‑obstetric surgical literature; these should be considered indirect support for our observations and interpreted cautiously.

Future research should include prospective multicenter randomized controlled trials with longer follow-up periods to validate these findings and explore the effects of barbed suture techniques on subsequent pregnancy outcomes, including rates of uterine rupture in subsequent deliveries and birth weight. Standardization of suturing techniques across different institutions and levels of surgical expertise would also enhance the applicability of these results in broader clinical practice.

Conclusion

This study demonstrates that, in the closure of uterine incisions during elective cesarean sections, the use of barbed double-needle sutures is associated with superior intraoperative efficiency, reduced postoperative pain and more optimal myometrial healing of the uterine scar compared to traditional smooth sutures. However, given the retrospective and single‑center nature of our study, these findings require confirmation in future prospective multicenter investigations with larger sample sizes and longer follow‑up.

Funding Statement

This work was supported by grants from the Health Commission of Hebei Province (Grant No. 20210831).

Data Sharing Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Ethics Approval and Consent to Participate

This study received approval from the Institutional Review Board and Ethics Committee of the Shijiazhuang People’s Hospital (Approval No. 2021-006), and was conducted in accordance to the tenets of the Declaration of Helsinki. Given the exclusive use of de-identified patient data, which presented no potential harm or impact on patient care, the need for informed consent was waived. This exemption was granted in line with regulatory and ethical standards for retrospective research.

Consent for Publication

This was deemed not applicable.

Author Contributions

Co-first author: Hongyan Wang and Haixing Wang. All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors have no conflicts of interest to declare.