Comparison of post-operative analgesia using Subfascial and Extrafascial approach of Transmuscular Quadratus lumborum block after lower segment Caesarean section.

Ultrasound guided Transmuscular Quadratus lumborum (TQL) block is a relatively new fascial plane block where local anaesthetic is injected adjacent to Quadratus lumborum muscle with the goal of anaesthetising thoracolumbar nerves. Multiple studies have demonstrated that TQL block is effective for post operative analgesia in parturients. Inadequate pain relief and lower limb weakness adversely affects the recovery of parturients who underwent Caesarean section, thus we found it worthwhile to assess the subfascial and extrafascial approaches of TQL block for post operative analgesia in this patient population.

Pregnant patients of age more than 18 years scheduled to undergo elective Caesarean section under spinal anaesthesia, fulfilling the inclusion criteria will be recruited under the study. After randomisation using computer generated random number table, parturients will be allocated either Group-I (Subfascial) or Group II (Extrafascial). In the operating room, all standard monitors will be attached and lactated Ringer’s solution will be started after taking IV access. Under all aseptic conditions, Subarachnoid block will be given at L3-4 or L4-5 using Quincke needle with 2-2.2ml of 0.5% Bupivacaine(H). After adequate sensory block is achieved, surgery will be started and rest of the intra-operative management will be as per protocol. After completion of surgery, dressing will be applied and TQL block will be given. A low frequency (5-8MHz) broadband convex probe is placed transverse to flank between lower costal margin and iliac crest to provide a view of Shamrock sign(transverse process of L4 and the three muscles Quadratus lumborum, Psoas major and Erector spine). A 21G 100mm Ultrasound block needle will be introduced in the plane of ultrasound beam and advanced till the anterior thoracic-lumbar fascia(ATLF). In Group I, needle tip will not puncture ATLF and drug will be deposited between Quadratus lumborum muscle and ATLF. In Group II, needle tip will puncture ATLF and drug will be deposited between Psoas major and Quadratus lumborum. 20 ml of 0.25% Bupivacaine will be given on each side in both the groups. Patients will be observed for 10-15 minutes and then transferred to post anaesthesia care unit (PACU). All patients will receive Injection Paracetamol 1g IV in PACU and the 8 hourly for 24 hours for pain control. Pain severity will be assessed using Numerical rating scale (NRS) at 0, 2, 4, 6, 12 and 24 hours after surgery. If NRS>3, Injection Diclofenac 75mg will be slow IV as First Rescue Analgesic and if pain still persists, Injection Tramadol 50mg slow IV will be given(Second Rescue Analgesic). Data will be checked for normality. Normally distributed continuous variables will be compared using Unpaired t test while Mann Whitney U test will be used for variables that are not normally distributed. Categorical variables will be analyzed by Chi square test or Fischer’s test. Statistical analysis will be performed by SPSS program for Windows, version 25.0.