Postoperative Analgesic Efficacy of Continuous Wound Infusion After Laparoscopy (PAIN)

Postoperative Analgesic Efficacy of Continuous Wound Infusion With Local Anesthetics After Laparoscopy (PAIN): a Randomized, Double-blind, Placebo-controlled Trial

Studies evaluating the effectiveness of continuous wound infusion (CWI) to manage postoperative pain following laparoscopy are markedly lacking. Especially, there was no study comparing CWI and placebo in treating gynecologic laparoscopy. Therefore, the investigators conducted this randomized, double-blind, placebo-controlled trial to investigate whether CWI of local anesthetics was an effective strategy for enhanced recovery after surgery (ERAS), compared with placebo in patients undergoing benign gynecologic laparoscopy.

Laparoscopic surgery has become an acceptable alternative for open surgery in treating benign gynecologic diseases. One of most important advantages of laparoscopy is a reduced postoperative pain compared with open surgery. Moreover, postoperative pain plays an important part in the enhanced recovery after surgery (ERAS) pathway. Although the length of hospitalization and recovery period after laparoscopy tends to be shorter, postoperative pain can still be an important issue. Recently, continuous wound infusion (CWI) providing a constant flow of local anesthetic directly a surgical wound postoperatively has been widely used to reduce pain after cesarean section and open surgery. Studies evaluating the effectiveness of CWI to manage postoperative pain following laparoscopy are markedly lacking. Especially, there was no study comparing CWI and placebo in treating gynecologic laparoscopy. Therefore, the investigators conducted this randomized, double-blind, placebo-controlled trial to investigate whether CWI of local anesthetics was an effective strategy for ERAS, compared with placebo in patients undergoing benign gynecologic laparoscopy.

Continuous wound infusion device used in this study was ON-Q Painbuster Silver Soaker (I-Flow Corporation, Lake Forest, CA, USA) comprised an elastomeric pump maintaining constant pressure to infuse 2ml/hour of analgesic to the wound through a catheter for 50 hours. In all participants, the surgeon inserted a 20-gauge, 6.5-cm, multi-holed soaker catheter through an introducer needle after closure of the transumbilical fascia. The catheter was located in the deep subcutaneous space, above the fascia near the skin incision. In the experimental group, an elastomeric pump filled with local analgesic solution (total volume 100ml) containing 750mg ropivacaine .

Continuous wound infusion device used in this study was ON-Q Painbuster Silver Soaker (I-Flow Corporation, Lake Forest, CA, USA) comprised an elastomeric pump maintaining constant pressure to infuse 2ml/hour of analgesic to the wound through a catheter for 50 hours. In all participants, the surgeon inserted a 20-gauge, 6.5-cm, multi-holed soaker catheter through an introducer needle after closure of the transumbilical fascia. The catheter was located in the deep subcutaneous space, above the fascia near the skin incision. In the control group, an elastomeric pump filled with filled with 100ml of 0.9% saline .

Continuous wound infusion device used in this study was ON-Q Painbuster Silver Soaker (I-Flow Corporation, Lake Forest, CA, USA) comprised an elastomeric pump maintaining constant pressure to infuse 2ml/hour of analgesic to the wound through a catheter for 50 hours. In all participants, the surgeon inserted a 20-gauge, 6.5-cm, multi-holed soaker catheter through an introducer needle after closure of the transumbilical fascia. The catheter was located in the deep subcutaneous space, above the fascia near the skin incision. In the experimental group, an elastomeric pump filled with local analgesic solution (total volume 100ml) containing 750mg ropivacaine . Ropivacaine is local analgesics.

Continuous wound infusion device used in this study was ON-Q Painbuster Silver Soaker (I-Flow Corporation, Lake Forest, CA, USA) comprised an elastomeric pump maintaining constant pressure to infuse 2ml/hour of analgesic to the wound through a catheter for 50 hours. In all participants, the surgeon inserted a 20-gauge, 6.5-cm, multi-holed soaker catheter through an introducer needle after closure of the transumbilical fascia. The catheter was located in the deep subcutaneous space, above the fascia near the skin incision. In the control group, an elastomeric pump filled with filled with 100ml of 0.9% saline .

The postoperative pain was measured using a visual analog scale (VAS) at 24 hours after surgery by several assessors who were blinded to the interventions. The scale was presented as a 10-cm line with verbal descriptors ranging from "no pain" to "worst imaginable pain".

Rescue analgesia (75 mg diclofenac sodium administered intramuscularly or 25mg pethidine intramuscularly) was provided upon participant request

Inclusion Criteria: age between 18 and 80 years, American Society of Anesthesiologists physical status (ASAPS) classification I-II the absence of pregnancy at the time of surgery Exclusion Criteria: allergy to amide local anesthetics including ropivacaine laparoscopic surgery needing ≥ 3 separate skin incisions history of ventral or incisional hernia pre-existing coagulopathy, neurologic or cognitive dysfunction systemic or regional (especially, umbilicus) infection previously taking opioids for acute or chronic pain inability to accurately express their pain.