Intraperitoneal gas insufflation will be required for laparoscopic visualization in space: a comparison of laparoscopic techniques in weightlessness.

Background: Laparoscopic surgery (LS) is contemplated during long duration space flight, but it typically necessitates intraabdominal hypertension (IAH) from insufflation to create a surgical domain. Because there are spontaneous changes in abdominal wall behavior in weightlessness (0g) that have been previously suggested to increase LS visualization, we studied the comparative laparoscopic visualization between gasless (noGAS), abdominal wall retraction (AWR), and standard 15 mmHg gas insufflation (GAS) during weightlessness.
Study Design: In-flight LS was performed on four anesthetized pigs during weightlessness obtained through parabolic flight in a research aircraft. GAS was studied during 27 parabolas and compared with 20 parabolas using AWR-LS and 12 with noGAS. Pelvic visualization was scored in real time during flight by 2 or 3 surgeons per parabola and postflight through review of compiled digital video disk (DVD) images by 29 independent reviewers. Physical measurements of the sagittal (anterior-posterior) and transverse dimensions of anesthetized pigs were recorded during 39 parabolas.
Results: Despite consistent increases in the sagittal abdominal dimension in weightlessness (GAS and noGAS), on-board scored visualization in 0g was unchanged for noGAS (p=0.78) and decreased during AWR (p=0.09), compared with 1g. Although AWR was considered feasible in 1g, spontaneous visceral movements reduced the surgical domain in 0g. Neither AWR nor noGAS was believed safe. But visualization during GAS in 0g was increased over that in 1g (p < 0.001).
Conclusions: Both noGAS and AWR are impractical in weightlessness. Gas insufflation will be required. With insufflation, visualization and perceived ability to perform LS was improved by weightlessness.