Gastroschisis is a congenital abdominal wall defect that develops in early gestation and causes the fetal abdominal organs to herniate into the amniotic environment. A distinction is made between complex and simple gastroschisis (SG) to predict the outcome for affected fetuses. Complex gastroschisis (CG) is associated with significantly higher morbidity and mortality rates compared to SG.

Even though 90% of affected fetuses with gastroschisis survive, efforts have been made to decrease serious gut-related health problems with the development of fetoscopic repair methods after repositioning of the bowel. So far, no results have been published on a procedure demonstrating successful closure of the abdominal wall defect. Recently, an innovative new approach has been developed that expects to be able to close off the abdominal wall defect using a silicone ring with membrane. This method requires no sutures and therefore has great potential in lowering mortality rates for CG. This method still lacks an instrument for insertion into the uterus and direct placement into the abdominal wall defect. Therefore, the goal of this thesis was to provide a proof of principle for the design of an instrument that enables the insertion and placement of the silicone ring with membrane during a fetoscopic repair procedure for the swift closure of the abdominal wall defect in CG.

At the start of the development of this instrument, the future surgical procedure was mapped out and a list of requirements was compiled. Several concepts were generated and developed until a final concept was selected. The instrument was named Intrauterine Ring Insertion System (IRIS). Prototypes were made of the designed instrument and the developed silicone patches. These were used in validation experiments to test whether the concept met the set requirements.

The experiments demonstrated that the new patches were able to close off the abdominal wall defect during and immediately after fetal intervention similarly to the original silicone ring with membrane. The experiments also showed that most (80%) of the new patches could be deployed into the abdominal wall defect with the use of the developed instrument. These tests used a validation model of a 24-week-old fetus with CG. However, loading of the patches into the instrument has not yet been successful. With the results of the experiments, the most optimal patch was chosen.

The goal of thesis was partially achieved, with successful placement but failed insertion of the silicone patch. The instrument-patch compatibility needs to be improved to able to complete the whole goal. The patch and instrument must be developed together as a system to get the best results. Several improvements have been suggested such as thinner graspers with increased grip, a pull or push loading mechanism and a thinner, more flexible patch. Further testing is needed to be able to use the innovative method for treatment of CG. These studies include a material study, preclinical tests in a fetoscopic treatment environment and animal studies. Lastly, a clinical trial must be completed to evaluate if the procedure can be used in humans and if it has the intended outcomes.