Rationale: Incisional hernias (IH) are a frequent complication after abdominal surgery. Prevalence of an IH varies depending on the previous abdominal procedure but could be as high as 70% in high-risk patients after open surgery. To investigate different fascia closure techniques in the prevention of IHs, the STITCH trial (NCT01132209) was designed. The study compared two different closure techniques for closure of a midline incision in adult patients undergoing an elective abdominal laparotomy. Patients were randomly assigned to the intervention group (small bites 5 mm x 5 mm) or the control group (large bites 1 cm x 1 cm). The study showed that small bites are much more effective than large bites in the prevention of an incisional hernia when closing a midline incision.

So far, it has not been studied whether there is still a long-term difference in incidence of incisional hernia between the small bites and the large bites group.

Objective: The primary objective of this study is to determine the difference in incidence of IH between the small bites and the large bites group after 10 years of follow-up from time of randomization in the STITCH trial. The secondary objectives are to measure quality of life (QoL), body image and cosmetic results, and abdominal wall function through questionnaires and physical examination in those patients who are still alive.

Rationale: Incisional hernias (IH) are a frequent complication after abdominal surgery. Prevalence of an IH varies depending on the previous abdominal procedure but could be as high as 70% in high-risk patients after open surgery. To investigate different fascia closure techniques in the prevention of IHs, the STITCH trial (NCT01132209) was designed, a randomized controlled trial in which 560 patients were included between October 2009 and March 2012. The study compared two different closure techniques for closure of a midline incision in adult patients undergoing an elective abdominal laparotomy. Patients were randomly assigned to the intervention group (small bites 5 mm x 5 mm) or the control group (large bites 1 cm x 1 cm). It showed that small bites are much more effective than large bites in the prevention of an incisional hernia when closing a midline incision.

So far, it has not been studied whether there is still a long-term difference in incidence of incisional hernia between the small bites and the large bites group.

Objective: The primary objective of this study study is to determine the difference in incidence of IH between the small bites and the large bites group after 10 years of follow-up from time of randomization in the STITCH trial. The secondary objectives are to measure quality of life (QoL), body image and cosmetic results, and abdominal wall function through questionnaires and physical examination in those patients who are still alive.

Study design: Assessment of long-term follow-up (10-13 years) of a randomized controlled multicenter study based on retrospective review of patient files and relevant imaging of the entire trial population, as well as questionnaires and physical and radiological examination of patient who are still alive.

Study population: Of the 560 included patients in the original STITCH trial, 545 completed the 1-year follow-up.

Intervention (if applicable): Not applicable. Main study parameters/endpoints: The primary outcome measure is the 10-year midline incisional hernia rate. The primary endpoint will be determined for the 545 patients of the original intention-to-treat population using Kaplan Meier analysis. In patients who died during follow-up, this will be evaluated by reviewing the available medical charts and radiological studies. CT-scans of the abdomen will be evaluated by the study-team. If CT imaging is not available, documented findings during physical examination by the relevant medical specialist will be considered. Patients being still alive with written informed consent to be contacted will be approached for their willingness to participate in this follow-up study, and after consent, we will reassess CT scans for an incisional hernia. All patients who are still alive and want to participate in this study will be asked to visit the hospital once for physical examination and an ultrasound of the abdominal wall.

Secondary outcome parameters include QoL and cosmetic outcome, Patients still alive with consent for participation will be sent the following questionnaires: MOS SF-36 and EQ-5D (QoL), Dresden Body Image Questionnaire (body image), Body Image Questionnaire (cosmesis), Hernia-Related Quality of Life Survey (abdominal wall function). Furthermore, readmission and surgical intervention rates related to midline IH will be determined for the entire study population.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Undergoing an ultrasound, physical examination and completing several questionnaires may be considered burdensome for the patient.

In order to be eligible to participate in this study, a subject must meet the following criteria:

• Available signed informed consent form for the original STITCH trial of the patients who are still alive.
• Or if the patients has died, the medical records are reviewed.

A potential subject who meets the following criteria will be excluded from participation in this study:

- Patients that on the original informed consent form of the STITCH trial, checked the box that they did not want to be approached for future follow-up studies.

Outcome assessors of previous radiological imaging and imaging created during our Long-term follow up will be blinded to the assigned randomization arm.