The purpose of the trial is to identify the "most simple non-inferior of three different methods", placebo, laparoscopic assisted transverse abdominal plane block (L-TAP) and ultrasound guided TAP block (US-TAP), using postoperative opioid consumption as a measure of efficacy in patients undergoing elective minimally invasive colon surgery in an ERAS setting. Postoperative pain scores and length of stay (LOS) will also be measured. The simplicity of the three methods is ranked as: 1) placebo, 2) L-TAP and 3) US-TAP.

Introducing laparoscopy in colorectal surgery and optimizing the postoperative care using the standardized protocols of enhanced recovery after surgery (ERAS) have significantly improved patient outcomes and LOS. Better pain management has the potential to further improve these outcomes. Since the introduction of ultrasound-guided abdominal wall blocks, much research has been done in that field, but no consensus has been reached concerning the optimal block technique; where to and when to inject the block, or which drug to use. Newly published randomized controlled trials show interesting results regarding the L-TAP which has several advantages to the US-TAP, including the ease of performance, less dependency on specialized skills or equipment and avoidance of intraperitoneal infiltration. but these results need to be solidified with multicentre trials. Besides optimizing postoperative pain management, better block techniques could potentially decrease LOS in patients after minimally invasive colorectal surgery.

Inclusion Criteria:

• Patients planned to receive curative elective minimally invasive colon surgery for colon cancer or adenoma without a planned ostomy. Colon cancer or adenoma is defined by a distance of more than 15 cm from the anal verge to the distal limitation of the tumour or adenoma as measured by rigid sigmoidoscope. The following procedural codes are included:
• Laparoscopic ileocecal resection
• Laparoscopic right hemicolectomy
• Other laparoscopic resection of both small and large bowel
• Laparoscopic resection of transverse colon
• Laparoscopic left hemicolectomy
• Laparoscopic resection of sigmoid colon
• Other laparoscopic colon resection
• Having given informed written consent.

Exclusion Criteria:

• Known allergy to local analgesics
• Known liver failure Class C according to the Child-Pugh Score
• Body weight of less than 40 kg
• History of being a chronic pain patient (weekly intake WHO step II or step III or adjuvant step I analgesic)
• Presence of concomitant painful conditions other than low back pain that could confound the subject's trial assessments or self-evaluation of the index pain, e.g., syndromes with widespread pain such as fibromyalgia
• Predictably non-compliant due to language barrier or psychiatric disease
• Patients rescheduled for open surgery, before the intervention has been administered
• Patients where the indication for surgery changes before the intervention has been administered
• Patients with known inflammatory bowel disease
• Patients who have previously undergone open major abdominal surgery defined by prior intraabdominal surgery with a midline or upper abdominal incision of more than 8 cm
• Incisional hernia
• Patients with a history of abdominal wall surgery including resection of the external oblique muscles, the internal oblique muscles, the transversus abdominis muscles, the rectus abdominis muscles or their fascial components
• Pregnancy (patients are screened using urine human chorionic gonadotropin upon admission if female and not postmenopausal).

After de-identification, individual participant data will be made available to investigators who provide a methodologically sound proposal for meta-analyses. Proposals should be directed to Claus A Bertelsen (cabertelsen@gmail.com). A Data Processing Agreement according to the EU General Data Protection Regulation has to be signed before data sharing.

For 15 years after publication

A methodologically sound proposal for meta-analyses