Effect of barbed suture versus conventional suture in laparo‐endoscopic single‐site cystectomy for ovarian mature cystic teratoma: An ambispective cohort study

To compare the effects of barbed suture (BS) and conventional suture (CS) on perioperative conditions and ovarian function in the excision of ovarian mature cystic teratoma (MCT) by laparo‐endoscopic single‐site surgery (LESS).


| Study population and data collection
The inclusion criteria were women aged 18-40 years who underwent resection of unilateral ovarian MCT by LESS and agreed to participate in the study. Exclusion criteria were: (1) previous ovarian surgery, including ovarian cyst resection, oophorectomy, and ovarian drilling, or other similar gynecological procedures; (2) previous salpingectomy or hysterectomy; (3) endocrine disorders, such as thyroid disease; (4) pregnancy or hormone treatment within 3 months before or after surgery; (5) missing data or loss to follow up. Based on the type of suture applied during surgery, eligible women were divided into the BS or CS groups. The two groups were matched for age, body mass index (BMI, calculated as weight in kilograms divided by the square of height in meters) and ovarian cyst volume at a ratio of 1:1.
Data for all women meeting the inclusion criteria were collected retrospectively from the internal hospital database, including baseline data, operative video and report, and perioperative outcomes.
The collected data were checked by another two researchers to ensure that there were no inconsistencies or errors. In addition, we completed follow up through outpatient interviews to assess ovarian function and ultrasound measurements of ovarian volume at 3 and 12 months after surgery.

| Baseline data
The baseline characteristics, including age, BMI, menstruation, gravidity, parity, pelvic ultrasound findings (including MCT location and volume), serum levels of anti-Müllerian hormone (AMH), folliclestimulating hormone (FSH), luteinizing hormone (LH), and estrogen (E 2 ) were retrieved. These tests were performed on the day before surgery during the proliferative phase of the menstrual cycle.

| Treatment and follow up
Surgeries were performed by two gynecologists who were trained and experienced in LESS. All surgeries were performed under general anesthesia and women were placed in a bladder lithotomy position during the surgery. To establish a single-channel single-port site, a 2.0-cm vertical intraumbilical skin incision was made, a 2.0cm rectus fasciotomy was performed to open the peritoneal cavity, and a HangT Port double-ring wound retractor (HangTian KaDi Technology R&D Institute, Beijing, China) was inserted into the umbilical incision. Pneumoperitoneum was induced with a set pressure of 12-15 mm Hg. To perform the laparoscopic procedures, the ovarian cortex was cut using monopolar scissors and the teratoma was then removed along the space between the ovarian cortex and cyst wall. The specimen was put in a disposable endo-bag, taken out through the umbilical incision, and sent for pathologic examina- Surgical findings including the operating time (from first skin cut and removal of single trocar), resection time, suturing time (time for suturing the ovary cortex), intraoperative blood loss (assessed by the decrease in hemoglobin), perioperative complications (intestinal, ureteral, or bladder injury, large-vessel injury, blood transfusion), additional port and conversion to laparotomy, postoperative morbidity (temperature > 38°C at least twice from the first day after surgery to discharge) were also recorded. Health economic indices, referring to length of hospital stay and hospital costs were also extracted.
Serum levels of AMH, E 2 , FSH, and LH were measured on the first day after surgery, these hormone levels were checked also during the proliferative phase at 3 and 12 months postoperatively.

| Statistical analysis
All statistical analyses were performed using SPSS version 18.0.0 (SPSS). The normal distribution of continuous variables was tested by Kolmogorov-Smirnov test. Descriptive statistics were reported as means ± standard deviation. Categorical variables were compared by χ 2 test and Fisher exact test. Continuous variables within each group were compared using paired Student t test, whereas non-parametric variables were compared using Wilcoxon signed-rank test. The difference in AMH levels between groups at baseline, day 1, 3 months, and 12 months after surgery were adjusted for the women's age and cyst volume using multivariate linear regression analysis. Values of P less than 0.05 were considered statistically significant.

| RE SULTS
We initially identified 118 women who underwent cystectomy for unilateral ovarian MCT by LESS between May 2019 and October 2020. BS and CS were applied in 50 and 68 women, respectively.
A total of 19 women were excluded for incomplete perioperative data, additional gynecologic surgeries, or refusal to participate in the study. Ultimately, 40 women were included in the BS group and 40 women matched for age, BMI, and ovarian cyst volume were included in the CS group at a 1:1 ratio ( Figure 1). Included women were followed up for 13.1 months on average (range 12.5-16.3 months).
The demographic characteristics and ultrasound findings are shown in Table 1. There were no significant differences in baseline characteristics between the two groups.   Figure 2a). In the CS group, the serum E 2 levels decreased on day 1 after surgery (P < 0.001) but had returned to preoperative levels by 3 months and 12 months after surgery, while no significant changes in E 2 levels were observed (Figure 2b). No clear changes were observed in FSH or LH levels in either group (Figure 2c,d).
Analysis of ovarian volume showed a non-significant difference in operative side ovarian volume between the 3-month and 12month postoperative follow ups in each group (Figure 3).

| DISCUSS ION
The present study is an ambispective cohort study comparing the appli- cuff suturing that also found that the use of BS reduces operative time compared with CS. 18,19 In particular, the obvious improvement to suturing and knotting efficiency associated with BS is attributable to bypassing the requirement of knots at the beginning and end of suturing.
Due to the welded closed loop at the end of the suture, BS can reportedly reduce the number of knots that are necessary to tie by four to six times the number used in CS. 20,21 Furthermore, the barb prevents the suture from moving backward when suturing, even without assistance to fix the suture, thus highlighting its major advantages in LESS and when suturing high tension incisions. 22 Although many studies have demonstrated that the application of BS can help reduce intraoperative blood loss, 23,24 no significant difference in the volume of intraoperative blood loss was observed between the two groups in our study. Compared with myomectomy or hysterectomy, the size and tension of the incision, blood supply to the organ, and suturing time are much shorter in ovarian MCT resection, which could explain why BS can impact blood loss in myomectomy or hysterectomy, but not in MCT. Although different types of specimen retrieval are available, including transvaginal extraction, and have several advantages, such as less pain postoperatively. 25,26 In the present study, all specimens were in-bag and removed through the umbilical incision. As the incision is relatively large and the teratoma tissue is soft (except the nodule), there is no need to add an additional incision, thus reducing the chance of infection and injury.
Ovarian MCT mainly occurs in women of child-bearing age, so special attention should be paid to the ovarian reserve. Changes in serum AMH levels are currently used to assess the ovarian reserve after surgery. [27][28][29] In our study, serum AMH levels decreased in both groups at day 1, 3 months, and 12 months after the operation com- Consistent with the study by Chang et al., 36 both groups in our current study showed non-significantly higher AMH levels at 12 months compared with 3 months after surgery. This trend suggests that ovarian function can recover after surgery, which may be attributed to a compensatory mechanism of follicles (i.e. increased secretion of AMH from each follicle), reperfusion after ovarian vascular remodeling, and derivation of follicles from smaller, healthy follicles. 36 Furthermore, changes in other ovarian reserve markers, such as FSH and LH, were unremarkable in our study except for E 2 levels, which significantly decreased at day 1 postoperatively compared with baseline in the CS group, but showed no significant difference at the 3-and 12-month follow ups, possibly due to low sensitivity in detecting an early decrease in the ovarian reserve. 37 The barb of BS that is exposed to the tissue exterior can hook to the bowel and cause obstruction. 38 Segura-Sampedro et al. 39 performed a search of electronic databases and found that BS was responsible for 15 cases of small bowel obstruction. In the present study, no obstruction were reported because of the relatively small incision in the ovary and small contact surface between the ovary and intestine. Furthermore, the fallopian tube covers the ovary and prevents it from attaching to the barb. Cutting short the suture stump and wrapping the BS with anti-adhesive film is recommended to prevent intestinal obstruction and pelvic adhesions. Other researchers have proposed a laparoscopic clip such as the LAPRA-TY® device. 40 Although BS is more expensive than CS, the total hospitalization costs were the same between groups, possibly because operating time was significantly shorter and cost of anesthesia was reduced correspondingly in the BS group.
To the best of our knowledge, this is the first study comparing BS and CS in perioperative conditions and their impacts on ovarian function following ovarian MCT resection by LESS. Nonetheless, our conclusions are limited by the small sample size, and the lack of 6-month post-surgery follow-up data. Therefore, a larger cohort, multicenter, prospective randomized controlled study is needed for further validation.
In conclusion, application of BS in cystectomy for ovarian MCT by LESS can reduce the technical complexity of the procedure and shorten operating time, without increasing impacts on ovarian function compared with CS.

AUTH O R CO NTR I B UTI O N S
JZ and SY conceived and designed the study and supervised the research; data were collected by YL and JL; statistical analysis was by YL, JL, JS, and YY; data were interpreted and presented by YL, JL, JZ, and SY; the manuscript was drafted by YL, JL, JS, YY, SY, and JZ. All authors discussed the results, contributed to the final manuscript, and approved the version for publication.

FU N D I N G I N FO R M ATI O N
The study was supported by the Medical-Engineering Cross Fund from Shanghai Jiaotong University (No. ZH2018QNB17).

CO N FLI C T O F I NTE R E S T
All authors declare no competing interests.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data and materials are available from the corresponding author on reasonable requests.