Transmuscular Quadratus Lumborum Block for Total Laparoscopic Hysterectomy.

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.

The TQL block is applied with the patient in the lateral position, with the side to be blocked turned upwards. The ultrasound transducer is placed in the transverse position at the posterior axillary line, just above the iliac crest, and adjusted to visualize the QL and psoas major (PM) muscles and the transverse process of vertebrae L3 or L4. The needle is subsequently inserted at the posterolateral end of the transducer and advanced in plane. The needle is advanced through the QL muscle until the tip of the needle penetrates the investing fascia of the QL muscle. The local anaesthetic is then injected in the interfascial plane, but posterior to the transversalis fascia (TF) and between the QL and PM muscles. Confirmation of correct application can subsequently be visualized when the two muscles are seen to spread apart on the ultrasound image.

The investigators want to perform evidence-based research using the USG TQL for patients undergoing TLH. The hypothesis is that the USG TQL block administered bilaterally and applied pre-operatively in the PACU or in the theatre for the TLH patients can reduce the postoperative morphine consumption by 50 % during the first 12 postoperative hours. It is considered a block with very little discomfort for the patient.

All patients scheduled for a TLH will be screened according to the inclusion and exclusion criteria. The suitable candidates will be asked prior to surgery, whether they want to participate in the trial. If so, before elective TLH, the patient will receive the block, allocated in a randomised fashion to either active LA or placebo. The block will be performed under standard perioperative monitoring by a trained and skilled physician from the department of anaesthesia. The active treatment will be a bilateral TQL block with 30 mL Ropivacaine 0.375% on each side, whereas the placebo group will receive the same volume of isotonic Saline, applied in the exact same way. The patients will all receive the same multimodal analgesic regimens, consisting of 1 g Acetaminophen, 400 mg Ibuprofen and 8 mg of Dexamethasone prior to surgery, and a regimen of 3 x Ibuprofen and 4 x Acetaminophen a day until discharge. An IV Morphine Patient-Controlled Analgesia (PCA) - pump will be used for 24 hours after instructions are given and the pump is set to begin in the PACU. In order to keep the pooled administration of local anaesthetic below the accepted maximum recommended dosage, neither local anaesthetic infiltration performed by the surgeon nor supplemental rescue regional techniques will be performed. Whenever pain exceeds an NRS of three despite the primary use of the PCA pump, the PACU nurses will administer additional Morphine or Sufentanil as they already do by the present standards.

Aim:

The aim with this study is to investigate the efficacy of the USG TQL block vs. Placebo in patients undergoing TLH.

The hypothesis is that the bilateral TQL block will significantly reduce the opioid consumption during the first 12 postoperative hours and significantly reduce the Numerical Rating Scale (NRS) pain score (0-10/10) and opioid related side effects.

Outcome:

Primary outcome:

The primary outcome of the study will be:

Morphine consumption in the first 12 postoperative hours (data from PCA pump and the patient's medical record).

The secondary outcomes will be:

(A) Pain intensity (NRS 0-10/10) in the study period at T0 (arrival in the PACU), after 15, 30 and 45 minutes. And again at 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 18, 21 and 24 hours postoperatively. In addition, NRS score will be recorded electronically in relation to all morphine administrations, since all patients must enter their NRS pain score on the PCA pump display in relation to administration of the PCA boluses.

(B) Total morphine consumption. Morphine consumption at 3, 6, 9, 12, 18 and 24 postoperative hours.

(C) Duration of block (time to first opioid). (D) Patient satisfaction with application of the block. (E) The degree of morphine-related side effects (PONV, itching, fatigue, etc.). (F) Time from operation to ambulation. The investigators regard these outcome parameters as essential for the selected patient group, and it is the investigators' hope that this could lead to a better amelioration of postoperative pain and reduced morphine consumption postoperatively.