Ultrasound-guided Transmuscular Quadratus Lumborum Block for Laparoscopic Hysterectomy. A Double Blind, Randomized, Placebo Controlled Trial.

Every year three hundred patients undergo hysterectomy at the department of obstetric and gynaecologic surgery at Zealand University Hospital, University of Copenhagen. The most common procedure is Total Laparoscopic Hysterectomy (TLH), which is the preferred technique in about four out of five hysterectomies at our facility. Multimodal analgesia consists of Paracetamol 1 g, Ibuprofen 400 mg and Dexamethasone 8 mg and Sufentanil 0.2 micrograms/kg for emergence if no contraindications are present. Standard general anaesthesia is total intravenous anaesthesia (TIVA) with an induction consisting of Remifentanil and Propofol infusions, a bolus of Propofol followed by muscle relaxation with Rocuronium. Patients are intubated in the trachea. Anaesthesia is maintained with Remifentanil and Propofol infusions and boluses of Rocuronium are administered whenever the surgeon requires it. Patients are always in Trendelenburg's position. Thirty minutes prior to emergence a bolus of Sufentanil 0.2 microg/kg is administered, as mentioned previously. Of interest: two other different opioid based regimens are currently used in the other two hospitals in Region Zealand where this procedure is performed. There is no national standards defined for dosages used for this kind of surgery. Additionally, no regional techniques are defined for this surgical procedure.

Our research group at Zealand University Hospital has conducted a thorough retrospective one-year survey for this patient group in order to define the quantity of the research problem. The electronic anaesthesia files, PACU files and ward files were meticulously reviewed. The survey revealed an accumulated morphine consumption in the first 12 postoperative hours of 44.1±30.8 mg of oral morphine equivalents in TLH patients. This dosage should be evaluated in relation to the standardized multimodal regimen described above.

Anaesthesiologists have primarily used either epidural catheters or long-lasting opioids as the basis for the postoperative pain management of expected or manifest moderate to severe pain. An epidural blockade can be contraindicated for some patients, and might cause bladder paralysis, lower extremity paralysis, hypotension etc. In addition, the epidural technique is labour-intensive in application as well as in its requirements for monitoring. Thus, the continuous epidural blockade is not a possibility of interest to the gynaecologists at our hospital. Therefore, until recently, opioids have been the sole treatment of pain, when over-the-counter medicine does not suffice. This presents a problem for the patients due to the well-known adverse effects of morphine including postoperative nausea and vomiting (PONV), itching, fatigue, constipation, confusion, respiratory depression and delayed mobilization.

Postoperative complications to surgery are more frequent in patients experiencing postoperative pain, and besides reducing the immediate postoperative pain perception, the investigators consider reduction of the total morphine consumption and the potential of reducing development of chronic pain through better treatment of the acute pain, as very interesting and promising for the patients in our study.

The investigators have the technical capability to improve perioperative pain management by taking advantage of USG peripheral nerve blocks (PNBs). The investigators' group of researchers have described the transmuscular quadratus lumborum (TQL) block and the mechanism by which the TQL block works has been proven in a major cadaveric study and some case reports.