Comparison of Analgesic Effect between Erector Spinae Plane Block and Transmuscular quadratus lumborum block after Elective Cesarean Section: A Prospective Randomized Double-Blind Study.

Patients after Caesarean section often suffer from significant postoperative pain. The multimodal analgesia  (MMA) regimen is the current standard of care which includes oral analgesic drugs and regional blocks. Trans-muscular Quadratus lumborum block (TQLB) and erector spinae plane blocks (ESPB) are relatively new block which has been used for pain relief in caesarean patients as an adjuvant to MMA. However, comparative studies are lacking. Therefore, we wish to evaluate and compare the analgesic efficacy of TQLB and ESPB in cesarean patients. After acquiring informed consent, we will select 60 pregnant females scheduled for routine lower segment caesarean section (LSCS) under spinal anaesthesia and will randomise them in two equal groups (Group-Q, and Group-E) by the computer-generated random table. Each patient will receive standard anaesthetic care as per hospital protocol. LSCS will be done under spinal anaesthesia. After completion of surgery patients will be positioned in the left lateral decubitus position and will receive either ultrasound-guided ESPB or TQLB with due aseptic precautions and sterile technique. ESPB will be given at the T9 level and using the transverse in-plane approach and TQLB will be given at the L4 level using the posterior in-plane approach. Each patient will receive a bilateral block with 20ml 0.25% bupivacaine mixed with 4 mg dexamethasone at each side. Regular postoperative analgesia will be given with an injection diclophenec 75 mg 12 hourly. Rescue analgesia will be given by patient-controlled analgesia (PCA) pump with tramadol. The pump setting will be, a bolus of 25mg, lock-out time 10 minutes and 4 hour limit of 100mg. The pain assessment will be done at 2,4, 8,12,24,48 hours with a visual analogue score (VAS) of 0 to 10 where 0=no pain and 10=most severe pain during rest and during active coughing. Time to first rescue dose will be considered the duration of analgesia. The primary objective is to compare the duration of analgesia and secondary objectives are a comparison of VAS scores, amount of tramadol used and the complications of the block. Quantitative data will be checked for normality and accordingly t-test or man-Whitney test will be used. Chai-square test or fisher-exact test will be used for qualitative data. The significant difference in the duration of pain relief will be assessed with the log-rank test and Kaplan-Meier graph will be drawn. The statistical analysis will be done with the help of statistical software SPSS version 21.