Low Versus Standard Intraabdominal Pressure in Robot-assisted Colorectal Cancer Surgery: A Double Blinded Randomized Clinical Trial

1. Introduction

Colorectal cancer is the third most frequent malignancy worldwide with an increasing incidence. Surgical resection is considered the gold standard for the cure of colorectal cancer. It is well recognized that an uneventful postoperative course is pivotal for a favorable prognosis. The length of stay (LOS) after colorectal cancer surgery has traditionally been between 1 and 2 weeks after surgery. This period has rightfully received considerable attention, and in the 2000s, Enhanced Recovery after Surgery (ERAS) protocols emerged as evidence-based perioperative practice guidelines designed to optimize the postoperative outcome and thereby shorten LOS. The ERAS principle is based on multimodal strategies, which collectively accelerates recovery and helps patients return to their baseline physical function more rapidly. ERAS has significantly reduced LOS without compromising patient safety or satisfaction. Minimally invasive surgery (MIS), including laparoscopic and robot-assisted techniques, is now an integral part of modern ERAS and a cornerstone of colorectal cancer surgery.

In general, MIS has been proven to reduce morbidity, postoperative pain and analgesic consumption, duration of hospital stay and patient satisfaction after colectomy. To ensure proper visceral exposure during minimal invasive surgery CO2 needs to be insufflated into the abdominal cavity. However, the insufflation and the inevitable increased intraabdominal pressure has been associated with postoperative shoulder pain and deep abdominal pain. The standard level of intraabdominal pressure is set around 12 mmHg in most situations and lowering the pressure could possibly decrease the morbidity associated with insufflation.

The first studies investigating the benefits and disadvantages of low-pressure laparoscopic surgery were performed in patients undergoing cholecystectomy and three major meta-analyses have suggested advantages in low-pressure surgery including reduced postoperative pain, analgesic use, and a slight reduction in length of stay.

There are only few studies on low pressure colorectal surgery and even fewer using the robotic platform, where the increased dexterity improves the surgical conditions in smaller confined spaces, which may be the result of lowering the pressure. Previously, Diaz-Cambronero et al. demonstrated that 78% of these procedures could safely be completed at 8 mmHg.