Objective: To test the preventive effect of the placement of an onlay mesh versus the use of a fascial closure device at the umbilical trocar site closure in order to prevent incisional hernia after laparoscopic surgery.

Methods: We designed a Two Center Randomized Controlled Trial were adult participants presenting for elective laparoscopic cholecystectomy, with or without an exploration of the common bile duct will be recruited, with allocation of each of them in 2 groups (prosthesis and control). Abdominal ultrasound scan focused on aponeurosis defects at the trocar sites will be performed at 12 postoperative months.

An ultrasound scan will be performed to avoid underdiagnosis bias since incisional hernia is frequently under detected by clinical examination.

Relevance: The prevalence of incisional hernia after laparoscopy might be as high as 30%, due to this reason is paramount to find a better closure technique.

There are few studies about incisional hernia including radiological exams in order to provide the exact prevalence of this pathology, even fewer literature exists about incisional hernia after laparoscopic procedures.

OBJECTIVE To test the preventive effect of the placement of an onlay mesh at the time of umbilical trocar site closure in order to prevent incisional hernia after laparoscopic surgery.

The estimated prevalence of incisional hernia after laparoscopy is 15- 25%, being even higher among patients with risk factors. Many different closure techniques exist, however few of them have been tested in Randomised Control Trials. Most of them lack an image technique to provide more accurate results.

METHODOLOGY

We designed a Two Center, Randomized Controlled Trial that will enroll patients undergoing laparoscopic cholecystectomy, with or without an exploration of the common bile duct. Participants will be randomized to 2 groups. The pneumoperitoneum technique will be achieved by Hasson technique. The closure procedure will take place at the end of the surgery, after the cholecystectomy is performed:

• Prosthesis: after suturing the aponeurosis with a J needle and 0 Polydioxanone, a lightweight, large-pore mesh made of PVDF monofilament (polyvinylidene fluoride - DynaMesh-CICAT, FEC Textiltechnik, Germany) will be placed onlay, overlapping 2cm in all directions from the edge of the aponeurosis incision at the umbilical trocar site. The mesh will be fixed to the aponeurosis with cyanoacrylate glue (Glubran®, GEM, Viareggio, Italy).
• Control: Closure of the aponeurosis will be performed by standard procedure: under direct vision, suturing the aponeurosis with a J needle and 0 Polydioxanone, with a stitch interval of ≤ 5mm.

An abdominal ultrasound scan focused on aponeurosis defects at the trocar sites will be performed at 12 postoperative months. Minimum follow-up will be 12 months.

All the adverse events will be registered and classified according to the Clavien Dindo classification.

An ultrasound scan will be performed to avoid underdiagnosis bias since incisional hernia is frequently under detected by clinical examination.

Relevance: The prevalence of incisional hernia after laparoscopy might be as high as 30%, due to this reason is paramount to find a better closure technique.

There are few studies about incisional hernia including radiological exams in order to provide the exact prevalence of this pathology, even fewer literature exists about incisional hernia after laparoscopic procedures.

Univariate descriptive analysis will present the results as means (with standard deviation and range) for the continuous variables and as numbers and percentages for the categorical variables. Bivariate analysis will be carried out among the variables of interest to describe their level of correlation and evaluate the possible differences between them. To evaluate the differences between the continuous variables we will use the comparison of means based on the T-Student and for the comparison of categorical variables the Chi-square test. Finally, linear regression models and generalized linear models (as appropriate depending on the response variable) will be used to study the dependence of the variables of interest, with other factors of study. Statistical analysis will be carried out using the SPSS (Statistical Package for the Social Sciences) Software (IBM SPSS Statistics 23). All tests will be bilateral with a level of significance of 5%. 100% of the data recorded will be analyzed, and the proportion of values lost in the variables of interest will be evaluated.

Inclusion Criteria:

• Patients undergoing elective laparoscopic cholecystectomy, with or without an exploration of the common bile duct, undergoing surgery in our hospital
• ASA (American Society of Anesthesiologists) \

The participant will not know if the umbilical incision has been close by standard technique or with the preventive mesh.

Also the radiologists performing the ultrasounds after 12 months will not have the information of Prosthesis/Control patient allocation