The Quadratus Lumborum block (QLB) was first described by Blanco in 2007. The main advantage of QLB compared to the Transversus Abdominis Plane block (TAP) is the extension of local anesthetic agent beyond the TAP plane to the thoracic paravertebral space. The wider spread of the local anesthetic agents may produce extensive analgesia and prolonged action of the injected local anesthetic solution.

Previous studies showed that both TAP block and QLB may reduce morphine requirements in the postoperative period in patients who had cesarean section under spinal anaesthesia. However there are no published reports comparing the 2 techniques.

The aim of this randomised controlled, double blinded study is to compare the analgesic efficacy of QLB compared to TAP block in patients who had cesarean section under spinal anesthesia.

After ethical committee approval, informed written consent will be obtained from all patients. A Sample size of 72 patients (36 per group) was calculated based on 15% reduction in morphine consumption with 0.05% significance and a power of 0.8.

Consenting patients scheduled to have elective cesarean section under spinal anesthesia will be randomised to receive bilateral QLB or TAP at the end of surgery.The dose of local anaesthetic in both groups will be 0.2 ml/kg 0.125% Bupivacaine. Allocation to either group will be done using closed envelope technique.

All the blocks will be performed in operation theatre after the end of cesarean section with intravenous access, ECG, BP, oxygen saturation by pulse oximetry monitoring and full resuscitation equipment and medication ready.

All patients will be in the supine position . Under ultrasound guidance a 22 Gauge, two inch Pajunk Sonoplex needle will be used for both techniques. The calculated dose of local anaeshetic will be injected bilateraly with intermittent aspiration. The spread of injectate will be seed on ultrasound.

All patients will receive the routine postoperative analgesia, comprising patient-controlled IV morphine analgesia and regular diclofenac and paracetamol.

All patients will be assessed postoperatively by a blinded investigator: in the postanesthesia care unit and at 2, 4, 6, 12, 24, 36, and 48 h postoperatively.

Inclusion Criteria:

Elective caesarean sections ASA 1 to 3 Written informed consent.

Exclusion Criteria:

Patient refusal Local infection at the site of injection Allergy to study medications Sepsis Anatomic abnormalities Systemic anticoagulation or coagulopathy Inability to comprehend or participate in pain scoring system Inability to use intravenous patient controlled analgesia