Comparison of ultrasound guided quadratus lumborum block and transversus abdominis plane block for post operative analgesia in patients undergoing elective caesarean section

Caesarean section is one of the most commonly performed surgeries in obstetrics, either as an elective or emergency procedure. With advancements in the anaesthesia management and improvement in the surgical techniques, the morbidity related to this procedure has reduced. However, post procedural pain remains one of the main concerns in patients undergoing any operative intervention.Surgical trauma leads to acute post operative pain that ends with tissue healing. In addition to the somatic and visceral components of pain in the early post-operative period, inadequate pain relief also has a propensity to progress to chronic pain syndromes that may have debilitating impact on the quality of life.1The Pfannenstiel incision which is most commonly employed in caesarean section and total abdominal hysterectomy (TAH) has also been associated with development of chronic pain syndromes if the acute pain of surgery is not managed adequately.Adequate analgesia helps in reducing the post operative stress response and morbidity, thereby improving the surgical outcome and facilitating rehabilitation. Females who have undergone caesarean section have even more compelling reasons to achieve optimal post operative analgesia compared to other surgical patients. Immobility due to inadequate pain relief may precipitate thromboembolic events in the parturients and can also hamper the mother-child bond. Effective pain control helps in early recovery, ambulation as well as breastfeeding and care of the newborn.Various analgesic modalities have been used to alleviate the pain associated with caesarean sections such as the use of oral analgesics which may be opioid or non-opioid, intravenous patient control analgesia system, local infiltration at the surgical site and neuraxial analgesia via epidural or intrathecal route. All of these modalities carry their own advantages and disadvantages. There is rising concern with the use of opioids as the sole analgesic modality as it can lead to significant amount of post-operative nausea and vomiting (PONV), pruritus, drowsiness, respiratory depression and other systemic side effects. Use of local infiltration or non-opioid preparations as the only analgesic modality are usually inadequate in providing pain relief. Neuraxial analgesia via epidural or intrathecal route for post-operative pain control may not be a convenient route as they need catheter based continuous infusion or repeated boluses to provide adequate effect. With increasing application of ultrasound in anaesthesia practice, interest in interfascial plane blocks has also increased. Ultrasound guided nerve blocks (ilio-inguinal nerve block) and inter-fascial plane blocks such as Transversus abdominis muscle plane block and Quadratus Lumborum Block have gained popularity as other modes of analgesia in postoperative cesarean section patients.Ultrasound guided nerve blocks have several advantages such as guidance of the needle under real time visualization, direct drug deposition as well as visualization of neural structures and related structures like blood vessels and tendons.The Transversus Abdominis Plane (TAP) block is a regional analgesic technique that blocks abdominal neural afferents by introducing local anesthetic into the neurofascial plane between the internal oblique and the transversus abdominis muscles thereby reducing the post operative pain in caesarean sections. A loss of resistance technique was used to locate the transversus abdominis plane. Hebbard et al described an ultrasound guided technique for the TAP block in 2007 which helped in overcoming the imprecision in the blind technique as accurate needle placement could be facilitated using ‘real-time’ imaging.Another interfascial plane block which has been shown to provide effective analgesia in patients undergoing caesarean sections is the ultrasound guided Quadratus Lumborum Block (QLB). Originally described by Blanco in 2007, QLB was further modified by Borglum, who deposited the drug in the inter-fascial plane between quadratus lumborum muscle and psoas major in a trans-muscular approach.Both these blocks have been shown to relieve post caesarean section pain, it may thus be reasonable to study their efficacy and compare them.Therefore, the present study is aimed at comparing the effectiveness of Ultrasound guided Quadratus Lumborum Block with Transversus Abdominis Plane block for adequate post operative analgesia in patients scheduled to undergo elective caesarean section.