# The Influence of Analgesic Wound Infiltration on Postoperative Pain and Inflammatory Cytokines in Open Colorectal Surgery: A Randomized Comparative Pilot Study

## TL;DR

This study shows that wound infiltration with analgesics reduces postoperative pain and affects inflammatory markers in colorectal surgery.

## Contribution

The study is the first to show how wound infiltration influences both pain and inflammatory cytokines in open colorectal surgery.

## Key findings

- Group 0 had significantly lower IL-6 levels than the control group.
- Group 3 had significantly higher IL-10 levels than the control group.
- Pain scores were significantly lower in all treatment groups compared to the control.

## Abstract

Background and Objectives: Surgical wound analgesia has been analyzed in many studies, but few have focused on its relationship with inflammatory markers. As such, we aimed to determine the influence of analgesic surgical wound infiltration in open colorectal surgery on the seric levels of pro- and anti-inflammatory markers and the associated efficacy in postoperative pain control. Materials and Methods: Forty patients who underwent open colorectal surgery were prospectively randomized: group 0, epidural analgesia; group 1, intravenous analgesia (control), group 2, preincision and prelaparoraphy infiltration; and, group 3, prelaparoraphy infiltration. Wound infiltration was performed with ropivacaine. We analyzed the levels of IL-6 and IL-10 cytokines before and 6 h after surgery and their correlation with pain scores. Results: The postoperative Il-6 levels were significantly lower in group 0 than in the control (p = 0.041). The postoperative Il-10 levels were significantly higher in group 3 (p = 0.029) than in the control. Six hours after the operation, the pain scores were significantly lower in all groups than in the control (p = 0.005, p = 0.022, and p = 0.017 for groups 0, 2, and 3, respectively). Pain scores were significantly correlated with Il-10 levels in group 2 (p = 0.047); in group 3, IL-10 levels directly correlated with those of Il-6 (p = 0.026). Conclusions: The analgetic effect of preincisional and prelaparoraphy analgetic infiltration was efficient. The analgetic infiltration of the surgical wound prior to closure stimulates both the inflammatory activator and regulator interleukins.