Which factor significantly increases the infection risk during surgeries?

Longer surgeries are associated with a significantly increased risk of infection due to several interconnected factors. The duration of a surgery plays a crucial role because the extended exposure of tissues and organs to the external environment can allow for more opportunities for bacteria to enter the surgical site. Prolonged surgical procedures can lead to increased tissue manipulation and potential damage, which further compromises the integrity of the skin and underlying tissues.

Additionally, longer surgeries often involve more extensive wound exposure, increasing the likelihood of contamination. The body's immune response can be affected during lengthy operations as well, as anesthesia, blood loss, and other factors may further reduce the patient’s ability to fight off infections.

The other factors mentioned, such as the use of sterile technique, are designed specifically to reduce infection risk. Minimally invasive procedures typically have the advantage of shorter recovery times and less tissue disruption, which usually correlate with a lowered risk of infection as compared to more extensive operations. In contrast, shorter surgeries can also have a reduced infection risk compared to longer ones due to less exposure time, making the selection of longer surgeries as a significant risk factor clear.