Objective
This study aimed to evaluate the safety and efficacy of absorbable barbed sutures for midline fascia closure in minimally invasive surgery for colorectal and gastric cancers in comparison with conventional absorbable monofilament sutures.
Study design
The Barbed trial is a prospective, single-center, randomized trial comparing the clinical outcomes of absorbable barbed sutures and monofilament sutures. A total of 312 patients will be enrolled and randomly allocated to use absorbable barbed or monofilament sutures for midline fascia closure in a 1:1 ratio. The surgical procedure used to close the midline fascia was standardized for both types of suture material. The investigator will examine the patients until discharge and at 6, 12, 18, 24, and 36 months postoperatively (Fig. 1). This study is ongoing at Jeonbuk National University Hospital and will last 3 years for each patient. This trial was registered with the Clinical Research Information Service of Korea.
Participants
Inclusion criteria
The inclusion criteria were as follows: (1) patients who were diagnosed with colorectal or gastric adenocarcinoma, (2) patients who underwent laparoscopic and robotic radical surgery, and (3) patients who were older than 20 years of age.
Exclusion criteria
Patients would be excluded if they fulfil any of the following exclusion criteria:
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Patients who underwent open surgery
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Patients with possible distant metastasis in preoperative studies
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Patients who underwent past abdominal surgery
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Patients who had midline incision of less than 1 cm or longer than 10 cm
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Patients who had incision which is not located at the midline
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Patients who underwent emergency operation, palliative surgery, or ileostomy or colostomy formation
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Patients with cancer-related complications (perforation or abscess)
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Patients who participated in another clinical trial within the past six months
Randomization
Eligible patients will be randomly allocated to use absorbable barbed or monofilament sutures for midline fascia closure in a 1:1 ratio. Stratified randomization was used, with a varying block size of 4. This randomization is based on an independent, computer-based sequence generated from the implementation of the dynamic algorithm with the cancer types as the stratifying variables. Randomization will be performed by statisticians who do not participate in this study.
Intervention
Surgical procedures are performed under general anesthesia and by an experienced surgeon. The location of the midline incision, which is supra-, trans-, or infra-umbilical mini-laparotomy, is determined according to the surgeon’s preference. At the end of surgery, fascia closure is achieved with absorbable barbed sutures (Stratafix®, Ethicon Inc., USA) for the study group and absorbable monofilament sutures (Maxon®, Covidien Inc., USA) for the control group. In all cases, the suture-to-wound length ratio is at least 4:1 for closure of the midline incision, and the inter-suture spacing is less than 1 cm. We avoid mass closure, which is performed with a suture bite, including all layers of the abdominal wall, except the skin. A single aponeurotic closure is applied to the midline incision in both groups. Subcutaneous tissue closure is not mandatory in this study. The skin can be approximated by using staples.
Outcomes and measurement
Primary outcome
The primary outcome of this trial is the frequency of incisional hernia 3 years after surgery. We use the definition of incisional hernia according to the European Hernia Society: “any abdominal wall gap with or without bulge in the area of a postoperative scar perceptible or palpable by clinical examination or imaging” [20]. All patients will be examined using computed tomography to evaluate cancer recurrence during the study period. Therefore, the investigator will examine the occurrence of incisional hernia through physical examination and computed tomography scans at 6, 12, 18, 24, and 36 months after surgery in the outpatient clinic.
Secondary outcomes
Postoperative complications, including surgical site infection (SSI), pain, and quality of life, will be compared between the absorbable barbed suture and conventional absorbable suture groups.
Postoperative complications is defined as any adverse events that required additional pharmacological, interventional, or surgical management within 30 days after surgery. All postoperative complications were graded according to the Clavien-Dindo classification [21]. SSI is defined according to the criteria of the Centers for Disease Control and Prevention [22]. We divided SSI into superficial, deep incisional, and organ/space-related types occurring within 30 days after surgery. We will evaluate postoperative pain on postoperative days 1, 2, and 3 using a numeral rating scale. The verbal numeral rating scale ranged from 0 to 10 (0 = no pain and 10 = worst pain). To analyze the quality of life, the SF-36 and body image questionnaire will be used and documented by the patient 12 months postoperatively (Fig. 2).
Sample size determination
The hypothesis being tested is that the incidence of incisional hernia at 3 years after surgery will be lower in the barbed suture group than in the monofilament suture group. The sample size was calculated on the basis of this analysis plan, assuming that the incisional hernia rate of the barbed suture and monofilament groups at 3 years after surgery will be 5% and 15%, respectively. We calculated that 141 patients in the barbed suture and monofilament groups would provide 80% power to detect a difference between two groups, using a two-sided α of 0.05. Assuming a 10% loss to follow-up, it is necessary to recruit 312 patients. Finally, 156 patients were assigned to the barbed suture and monofilament groups.
Statistical analysis
A planned analysis will be performed after all patients have completed their 3-year follow-up. Categorical variables will be presented as numbers with percentages, and continuous variables will be presented as means with standard deviations or medians with interquartile ranges. The analysis will be performed using the intention-to-treat approach. The primary outcome will be analyzed using Chi-squared and Kaplan-Meier tests. Risk factors for incisional hernia will be analyzed using the Cox regression analysis. Secondary outcomes will be tested using the Chi-squared test for categorical variables and the t-test or Mann-Whitney test for continuous variables, as appropriate. The level of statistical significance will be set at p < 0.05.
Ethics
This study will be conducted in accordance with the Declaration of Helsinki and the International Conference on Harmonization-Good Clinical Practice E6 recommendations. This study was approved by the Institutional Review Board of Jeonbuk National University Hospital (CUH 2021-09-040). The study protocol was registered with the Clinical Research Information Service in Korea (KCT0007069). Informed consent will be obtained from all participants. Adverse events will be treated according to the standards of care. No biological specimens will be collected during the trial. Datasets will be anonymized, and only summary data, which cannot identify individual participants, will be presented in the manuscript. The findings will be published in peer-reviewed journals and disseminated through scientific and academic conferences.