Comparison of erector spinae plane block versus retrolaminar block using ultrasonography for postoperative analgesia in patients undergoing percutaneous nephrolithotomy.

Renal stones are a significant medical issue and percutaneous nephrolithotomy is the generally considered treatment for large or staghorn calculi. Even though it’s a minimally invasive endourological procedure, PCNL is associated with severe visceral and somatic pain which is attributed to various factors, including surgical incision, renal parenchymal injury, renal capsule stretch and nephrostomy tube insertion. Post operative pain is a complex condition that needs a multimodal approach and good pain management which can decrease hospital stay, rate of complications and decrease overall health cost. Thus, the Multimodal postoperative pain management approach helps in reducing opioid related side effects early recovery and helps to shorten the duration of hospital stay.  While appropriate post operative analgesic management in these patients involve various techniques such as intravenous systemic analgesics, regional techniques such as Epidural analgesia, Paravertebral Block and Quadratus lumborum Block and local anesthetic infiltrations, these systemic analgesics have found to have few side effects and various regional techniques are found to be invasive. Hence the interfascial plane blocks such as Erector Spinae Plane Block, Retrolaminar Block, Transverse abdominis plane block are found to be the safer alternatives and less invasive. Erector Spinae Plane Block is a newer approach of paraspinal fascial plane block which was first described by Forero et al., in 2016 in which local anesthetic is injected deep to the erector spinae muscle and superficial to the transverse process, to attain block in the dorsal and ventral rami of spinal nerves. This provides multilevel analgesia, is simple and safe far from pleura, major vessels, neuraxis and can be given bilaterally. Whereas Retrolaminar Block is a modified paravertebral technique with a local anesthetic injected at the vertebral lamina, deep to the erector spinae muscles but closer to the lamina. It is an easier technique than the ultrasound-guided paravertebral block that is technically challenging and time consuming. It is far from pleura and neuraxis and hence found to have minimal risk of pneumothorax. With this background, the present study is undertaken to determine and compare the efficacy of ultrasound guided Erector Spinae Plane Block versus Retrolaminar Block for postoperative pain management in patients undergoing PCNL.