Procedure specific postoperative pain management (PROSPECT) guidelines for abdominal hysterectomy published in 2006 recommended laparoscopic or vaginal hysterectomy as a preferred surgical technique. Multimodal postoperative pain management plane includes cyclooxygenase-2 (COX-2) selective inhibitors, and/or conventional non-steroidal antiinflammatory drugs (NSAID) in combination with strong opioids for high-intensity pain or with weak opioids for moderate- or low-intensity pain. Paracetamol also was recommended in combination with COX-2 inhibitors or conventional NSAIDs. Epidural analgesia was recommended for high-risk patients. PROSPECT guidelines updated in 2018 discuss only perioperative approach for laparoscopic hysterectomy. However, hysterectomy technique has been switched from total abdominal to laparoscopic approach. In low resources settings, laparoscopic technique is nor well developed neither available to many patients. Furthermore, the majority of patients undergo total abdominal hysterectomy (TAH), that is very painful procedure. Quadratus lumborum block (QLB) is a regional analgesic technique described by Blanco in 2007. Society for Obstetric Anesthesiology and Perinatology (SOAP) and European Society for Regional Anaesthesia and Pain Therapy (ESRA) recommended QLB for post-Cesarean pain management in cases where intrathecal morphine could not be used or for breakthrough pain. Previous reports have shown that QLB is effective in providing pain relief after various abdominal operations. The effects of QLB for laparoscopic hysterectomy is controversial. We would like to see if QLB can provide analgesic benefits in multimodal pain management after TAH in our clinical settings.

Participants will be randomly allocated into two groups. Experimental group will have QLB type 2 at the end of surgery, before emergence from general anesthesia. Control group will not have QLB.

All cases will be done under general anesthesia. During the surgery, the patients will be monitored with 5-lead electrocardiography, pulse oximetry, non-invasive blood pressure and end-expiratory CO2.

Standardized general anesthesia include induction with a propofol bolus of 1.5-2.5mg/kg and rocuronium 0.6mg/kg. Fentanyl 2 mcg/kg will be given at induction, and repeated to keep the blood pressure and heart rate changes up to 20% of baseline. Sevoflurane in a 50% air/50% oxygen mixture with an end-tidal of 1.5 vol% will be used as the maintenance agent. Mechanical ventilation will be maintained to keep the end-expiratory CO2 values between 34 and 36 mmHg. Incremental dose of rocuronium (0.15 mg/kg) will be given every 30 min or when needed. At the end of the surgery, after partial recovery from neuromuscular blockade, patients will receive atropine 0.01 mg/kg and neostigmine: 0.02mg/kg before tracheal extubation. Participants will be referred to the post-anesthesia recovery room after extubation and adequate hemodynamic and respiratory recovery.

Postoperative pain management will include ketoprofen and morphine.

Inclusion Criteria:

1. endometrial carcinoma or uterine fibroids
2. American society of anesthesiologists (ASA) physical status 1-3,
3. Participant's body weight > 50 kg,
4. Written informed consent signed.

Exclusion Criteria:

1. Patient's refusal
2. Allergies to any study medication
3. Local skin infection on the site of QLB injection

3. Body mass index > 40 kg/m2 4. Inability to comprehend or participate in scoring scales 4. Deformations that could possibly affect the spread of the local anesthetic in the quadratus lumborum muscle plane 5. Quadratus lumborum muscle plane not seen in ultrasound examination 6. Patients on regular use of opioids 7. Psychiatric disorders

Participants undergo total abdominal hysterectomy.

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Data requests can be submitted starting 9 months after article publication and the data will be made accessible for up to 24 months. Extensions will be considered on a case-by-case basis.

Access to trial IPD can be requested by qualified researchers engaging in independent scientific research, and will be provided following review and approval of a research proposal and Statistical Analysis Plan (SAP) and execution of a Data Sharing Agreement (DSA). For more information or to submit a request, please contact nada.pejcic@gmail.com