Efficacy of an Anterior Quadratus Lumborum Block vs. a TAP-block for Inguinal Hernia Repair

One of the most common complications after hernia repair is postoperative and chronic pain. Postoperative pain is an expected but undesirable effect after an operation, which can result in an prolonged hospital stay or longer time to return fully to normal daily activities. There are indications that an insufficient treatment of postoperative pain is a risk factor for persistent or chronic pain after open and laparoscopic inguinal hernia repair (Berndsen FH 2007) (Nienhuijs SW 2005).

TAP (transverse abdominis plain) block is a recommended multimodal method of reducing postoperative pain in laparoscopic and open surgery (El-Dawlatly AA 2009; 102). TAP block (Meyer A 2015) and an anterior Quadratus Lumborum Block (Adhikary, S.D. 2017) are both recommended for inguinal hernia repair. The objective of this study is to determine, whether the use of a perioperative echo guided unilateral TAP block has a superior effect on postoperative pain after laparoscopic inguinal repair compared to the anterior Quadratus Lumborum Block with a long acting local anesthetic. There will be no further analysis in this study regarding the evidence of open hernia inguinal repair and chronic pain.

The primary endpoint:

Opioid consumption measured in orale morphine equivalents four hours postoperative.

The secondary endpoints:

Opoioid consumption measured in orale morphine equivalents after 24 hours, 48 hours and seven days postoperative.

Postoperative nausea and vomiting measured on a NRS scale 0-3 at timepoints 1,2,3 hours, 24 hours, 48 hours and 7 days. Sedation scores measured on a NRS scale 0-3 at timepoints 1,2,3 hours, 24 hours, 48 hours and 7 days. .

There will be conducted a telephone interview by a blinded study nurse at 24 h, 48 h and 7 days, interviewing the patients as to their NRS score, nausea, sedation, level of activity and satisfaction with their overall treatment.

Power and Sample Size Calculator A pilot consisting of 12 patients was performed. The patients recieved a TAP block before a elective laparoscopic inguinal hernia repair. The mean oral morphine equivalents after four hours postoperative was 8.75 mg and the standard deviation 5.93 mg. With a significant clinical difference of 50%,an α = 0,05 and an effect size of 80% (β = 0,2) the total sample size is 60 patients with 30 patients in each group.

Premedication: Paracetamol by weight (2 grams (g)>70 kilos (kg) <70 years, 1,5 g <70 kg >70 years, 1 g <50 kg) , Diclofenac by weight (100 milligrams (mg) >70 kg <70 years, 50 mg <70 kg >70 years).

General anaesthesia: TCI (Target Control Infusion = Anesthesia protocol): Propofol and Remifentanil Surgical procedure: Laparoscopic inguinal hernia repair. 5 mg/ml 10 ml Ropivacaine in the ports peroperatively.

Postoperatively:

• Oral paracetamol 1000 mg every 6 h
• In case of insufficient analgesia (NRS≥4) oxycodon 2-5 mg will be administered by a postoperative nurse.
• When nausea and vomiting occurs postoperatively, ondansetron 4 mg IV administers as the drug of first choice followed by droperidol 0,625 mg IV if the nausea/vomiting persists.

Inclusion criteria

;

• Age > 18 years
• BMI (body mass index) 20-35
• ASA (American Association of Anesthesiologists Classification system for physical status) I-III.
• Scheduled for elective laparoscopic inguinal hernia operation

Exclusion criteria

• Allergy to latex, local anesthesia or opioids
• Chronic pain with daily opiate use
• Patients with severe renal and/or hepatic disease
• Local infection at the site of injection
• Systemic infection
• AV block 2-3
• Inability to understand written or spoken Norwegian
• Inability to cooperate
• Dementia
• Known abuse of alcohol or medication
• Coagulation disorder
• Pregnancy Previously operated with same side operation.