An abdominal spacer that does not require surgical removal and allows drainage of abdominal fluids in patients undergoing carbon ion radiotherapy.

Abdominal spacers are useful for maintaining the distance between the target tumors and surrounding tissues, such as the gastrointestinal tract, in patients treated with carbon ion radiotherapy. Surgical intervention to remove the spacers is sometimes necessary because of abdominal infections triggered by long-term spacer placement or intestinal perforation. Therefore, spacers that do not require surgical removal and provide effective drainage against abdominal infections are urgently needed. This study aimed to develop a spacer that could be removed non-surgically and one that provides the therapeutic effect of drainage in patients who receive carbon ion radiotherapy for abdominal tumors. A novel fan-shaped spacer was constructed from a film drain that was folded along the trigger line. Simple withdrawal of the trigger line caused the film drain to fold and the holding lines to become free. We performed laparoscopy-assisted insertion with pneumoperitoneum and blind removal of the spacer fourteen times using a porcine model. Saline in the abdominal cavity was effectively aspirated using the spacer. Our novel fan-shaped spacer could be removed safely without surgery and was able to drain fluid effectively from the abdominal cavity.