The goal of this observational study is to learn about the functioning of the abdominal wall in patients who underwent hybrid (open- and laparoscopic) incisional hernia repair. The main objective is to assess the anatomical restoration and function of the linea alba one year after surgery by ultrasonography and mean peak torque during trunk flexion using a BioDex machine.

Rationale: Abdominal wall functioning has been reported to be higher in patients that underwent open incisional hernia repair compared to laparoscopic incisional hernia repair. With the use of a recently developed hybrid approach, we aim for a functional anatomical restoration of the linea alba while also achieving the technical advantages of the hybrid approach.

Objective: The main objective is to asses functional anatomical restoration of the linea alba through functioning in mean peak torque, and ultrasound examination.

Study design: Multicentre prospective cohort study. Study population: Adult patients with a midline incisional hernia ≥4 cm and ≤10 cm.

Intervention: Not applicable. Main study parameters/endpoints: The primary objective of this study is to assess anatomical restoration and function of the linea alba one year after surgery by ultrasonography and measuring the mean peak torque during trunk flexion using a BioDex(trademark) machine.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: No risk is associated with participation other than known complications for incisional hernia repair. HYDRA is part of standard care in the Alrijne Hospital, and the technique has previously been published. The mesh used in this study is being used on a world-wide scale. We do not expect additional risks with this study. As participants have to visit the Erasmus Medical Center (Erasmus MC) an additional three times and have to fill in additional questionnaires, there is a burden for enrolled patients.

Inclusion Criteria:

• 18 years or older
• Scheduled for elective HYDRA-surgery
• Midline incisional hernia larger than 4 centimetres in mean width
• Sufficient knowledge of the Dutch language to be able to understand and fill in the questionnaires
• Signed informed consent form by patient

Exclusion Criteria:

• Pregnant at inclusion
• Inclusion in other trials with interference of the primary and secondary endpoints
• American Society of Anesthesiologists Classification (ASA Classification) > 3
• Hernia defect larger than 10 centimetres in mean width
• Incarcerated hernias or emergency procedure
• Unable to perform a trunk flexion
• Incapacitated patients

Patients scheduled for Hybrid repair of their incisional hernia

The data is partly retrieved from patient files and from questionnaires (after informed consent). Even though the data is pseudonymized, there is too much risk of confidentiality breach.